Final Report Summary - GASTONE (New powertrain concept based on the integration of energy recovery, storage and re-use system with engine system and control strategies)
Executive Summary:
The final goal of the project GASTone has been the high efficient energy conversion for a natural gas heavy duty engine, namely the FPT Cursor8 NG Euro VI installed in the IVECO Stralis NG Euro VI MY2014.
The energy recovery strategy is based on two mainstreams:
• Recovery of a portion of the kinetic energy thanks to the adoption of a belt driven generator (BSG).
• Recovery of the waste heat with an energy cascading approach: thermoelectric generator operating at high temperature (TEG) and a subsequent turbo-generator (TBG).
The Project most important outcome has been a new powertrain concept based on a combined energy recovery, storage and re-use system integrated and optimized with the engine system and controls.
The above mentioned functions were integrated into a multilevel board net architecture, created comprising e-auxiliaries, e-generation and energy storage, with a central control unit integrating all control and power electronic, to achieve an effective, overall electric energy management within a beltless engine concept.
The operation strategies for all e-components, following typical heavy duty truck drive cycles demand were defined and a control software was developed and implemented into the e-system controller.
In the end the experimental activity enabled the bench testing of both the reference engine and the GASTone power pack; the 6 cylinders CNG engine was equipped with e-auxiliaries and mounted at test bench after metrological measurements for configuration sign off. Afterwards new engine components were integrated together with control system to manage e-devices.
The engine characterization in n. p. configuration and in GASTone configuration was executed in terms of performance, fuel consumption, emissions, heat rejection, friction and pumping losses and turbocharger performance (boost, flow rate), the measurements were done at fixed point representative of relevant engine speed/load of real mission and then a dynamic behavior was assessed at dynamic engine test bench according to WHTC and real life conditions (ACEA cycle). The results yielded by the experimental activity were the basis and input data for the benefit estimation at vehicle level and applicability study on a diesel engine, carried out using the dynamic model of the engine and its energy balance developed at the beginning of the project.
The total electric production generated by the TEG, TBG and BSG was estimated: the BSG in deceleration periods is the main producer while the TEG and the TBG contribute to the system approximately in the same percentage; the best combination apparently is the BSG system used as a producer as well. Nevertheless, the combination of the BSG system with the TEG and TBG results also very attractive being able to achieve a considerable fuel saving rate. In the investigated case, the average exhaust gas mass flow in the Diesel engine resulted to be double than in the CNG engine. Among the inquired technologies, the generation of electricity by the TBG is controlled by the mass flow as the dominant variable and therefore this latter technology is likely to be more adequate to Diesel engine applications. In this case, the average temperature over the cycle by the CNG engine is 22% higher than by the Diesel engine. Therefore, recovery technologies which control factor is the temperature, as the TEG, show a greater potential in CNG engines.
In conclusion the most versatile technology used in the GASTone approach is the BSG system, able to produce electricity at any time ensuring the availability of the electricity even though it is not always for free.
The GASTone engine system was analyzed as well as its on-board integration so to split the costs per function and to estimate the overall cost, based on different market scenarios; the cost issue was considered both from user point of view and industrial point of view taking into account direct costs as well as indirect costs.
In the GASTone project, the total cost of ownership was evaluated with the purpose to compare the current production heavy duty truck IVECO Stralis Natural Gas Euro VI to the same vehicle equipped with all the new GASTone technologies, resulting that the purchase cost of GASTone concept vehicle would be significantly higher than a comparable heavy-duty NG Euro VI vehicle, resulting in a not favorable payback time.
Project Context and Objectives:
The heavy-duty vehicle manufacturers are a paramount chain link of an efficient freight transport in Europe, with the sector generating over 5 billion € trade surplus for the European Union in 2014.
In 2015, more than 350,000 heavy commercial vehicles (HCV) were produced in the EU, more than 150,000 of which in the countries participating to the project GASTONE, while over the first three quarters of 2016 EU exports of light and heavy commercial vehicles summed up to around 7.6 billion €, generating a trade surplus of about 2 billion €.
Trucks are economic goods, what makes fuel efficiency a key element in the purchase decision; because of the competition among freight transport service providers, final customers will continue to be very sensitive to indirect costs and will be interested in technologies that help reduce operative costs and Total Cost of Ownership (TCO).
Fuel, reaching 30% of the running costs in the transport sector, is one of the most important competitive factors in the heavy-duty vehicle market.
With the annual average travelled distance likely to remain above 100,000 km, the introduction of a new-generation of fuel-efficient engines and trucks is expected to improve fleet efficiency, thereby contributing to curb fuel costs.
Thanks to the availability of large worldwide reserves, natural gas (LNG/CNG) benefits from favorable and stable pricing, resulting in lower fuel costs and making it a truly viable alternative to Diesel fuel.
Carbon soot, NOx, and GHG emission reduction and fuel efficiency enhancement will drive global regulations, both Euro VII and EPA until year 2025, thus EU VI and potentially EU VII compliance and lifecycle cost are expected to remain a serious concern for fleets in the close future.
Of all emissions standards, Euro VI had the greatest impact on vehicle design, as it required combining a high number of technologies in order to achieve near-zero levels of emissions.
IVECO overcame this challenge with a unique breaking through solution with no exhaust gas recirculation (EGR) for its whole range of trucks from 7.5 to 50 t Gross Vehicle Weight.
Since the late 90s, IVECO has developed a wide range of engines, ranging in power from 136 hp to 330 hp, that run either on natural gas or bio-methane (in its renewable version), whether compressed to 200 bar (CNG) or in liquid form (LNG) at -130 °C.
Twenty years of experience built IVECO's status as leader in alternative natural gas-powered propulsion, with more than 24,000 engines produced.
FPT Industrial developed a proprietary multi-point CNG engine for low consumption that meets Euro VI/EPA 10 standards and adopted a zeolite-based unique Selective Catalytic Reduction (SCR) technology to achieve Euro VI emission standards; without EGR, SCR or particulate filters, the latest-generation Cursor 8 CNG Euro VI engine requires no additive and is 100% compatible with bio-methane. Thanks to its particularly efficient "stoichiometric" combustion, its pollutant emissions are much lower than those mandated by the Euro VI Directive as of 1st January 2014, with significantly less fine particulate matter and NO2 which are responsible for respiratory diseases in urban locations.
Entrusting the entire anti-emission process to the HI-SCR system, IVECO escaped the trend for increasing complexity of Diesel engines too, while improving reliability and, ultimately, bringing reductions in the total cost of ownership (TCO).
However, as Heavy-duty vehicles account for roughly 5% of Europe’s greenhouse gas emissions (GHG), with the future EU legislation on CO2 from trucks requiring a declaration of CO2 values for each truck produced based on all vehicles sold every year, natural gas is expected to achieve a noticeable penetration rate among different powertrain fuels, with CNG/LNG rapidly emerging as a key fuel expected to attain a global market share of up to 8.5% by 2022 when global sales are forecast to reach over 390,000 units.
Moreover, today not only natural gas engines, but also hybrid powertrain adoption is expected to increase in the years to come; at the same time downsizing, down speeding, in-cylinder improvements, reduction of friction losses, fast warm up and waste heat recovery are emerging as most important R&D topics for the next generation of powertrains, besides hybridization.
However when the project GASTone started in year 2013, full hybrid solutions of the powertrains for the heavy commercial vehicles were not feasible due to economic and technical constraints and consequently the research work was focused on the electrification of the auxiliaries with an outlook to an advanced starter generator solution with possible mild hybrid functions.
Turbocharging technologies will also play an increasing role in powertrain strategies as power density requirements in major commercial vehicle markets increase, demanding very high compression ratio, while electrically assisted turbocharging is effective in transient response.
In the end the project objectives have been pursued mainly through three different approaches:
1. The energy recovery from the exhaust gases heat with a cascade approach thanks to the adoption of an advanced thermoelectric generator and a turbo- generator.
2. The integration of a smart kinetic energy recovery system to substitute the alternator and generate decarbonized electric energy during decelerations.
3. The electrification and control of the main auxiliaries (coolant pump, auxiliary e-supercharger, etc.) by using the produced electric energy.
The above mentioned functions were integrated into a multilevel board net architecture, created comprising e-auxiliaries, e-generation and energy storage, with a central control unit integrating all control and power electronic, including a DC/DC-converter to achieve an effective, overall electric energy management within the beltless engine concept.
The operation strategies for all e-components, following typical heavy duty truck drive cycles demand were defined and, based on this operation strategies, a control software was developed and implemented into the e-system controller.
Furthermore, the thermoelectric generator (TEG) required specific integration into the exhaust system of the selected CNG internal combustion engine, minimizing any negative influences on the exhaust after-treatment and the pumping losses, on one side and the integration of the cold side heat exchanger into the engine cooling system on the other side, also considering the interaction of the thermoelectric generator and its produced energy with the power grid of the power pack.
In the end the experimental activity enabled the testing of both the reference engine and the GASTone power pack.
Project Results:
Reference engine, vehicle and assessment methodology definition.
The reference engine and vehicle were defined to be the FPT Cursor8 NG Euro VI installed in the IVECO Stralis NG Euro VI MY2014, and their working conditions and vehicle energy balance (fuel consumption thermal, electric,...) were identified in order to define a real world mission, which was chosen to be the WHTC and ACEA cycles.
A specific assessment procedure to show the improvement of the proposed GasTone Concept with respect to state of the art engine was defined. The main performance parameter chosen were the energy efficiency.
Model based system benefit estimation
A dynamic model of the system was developed, to simulate all the occurring interactions among systems, engine and vehicle and to estimate the electrical balance, the heat rejection demand and temperature levels and estimate the overall fuel economy.
The system concept design was drafted identifying the most promising configuration.
An advanced concept with a central control unit integrating all control and power electronic for each e- auxiliaries, generators and e-storage including a DC/DC-converter and an overall control strategy were established to ensure the energy efficient system operation management among e-generation, energy consumption and storage within the beltless engine concept.
The overall system architecture and the individual components were defined and sized and their technical specification identified. A smart board net architecture was created comprising e-auxiliaries, e-generation and storage using a beltless engine concept based of a 48-volt electrification.
Thermoelectric Generator (TEG)
Thermoelectric modules were combined in a system level design optimizing their positioning, orientation and configuration in the thermoelectric generator; the TEG consists of 32 cartridges which are electrically connected in series.
Since it is necessary to regulate the temperature and mass flow of the exhaust gas reaching the cartridges to avoid their overheating, a bypass system was implemented to reduce the overall exhaust gas flow into the TEG system, in case of high load operating points; the bypass was realized as a rotary valve; a control strategy for operating the bypass system and a power point tracker are developed and implemented in the TEG system.
Based on appropriate simulation models of the thermo-electrical behavior of the TEG modules, a Matlab/Simulink model was developed for the control of the TEG system.
Compiled software-models for the internal control of the TEG system were implemented onto rapid prototyping hardware (dspace-AutoBox).
The TEG system was validated on a functional test bench in terms of power output.
The functional test bench was designed to simulate the gas engine used in the project in terms of exhaust gas temperature and mass flow. As the engine has very high values of gas temperature and mass flow it was not possible to reach those maximum values with the functional test bench, the limits of the test bench being about 510°C gas temperature at 300kg/h mass flow, close to the design point.
The TEG system was functionally tested and the system validation was done with steady state points of 300°C up to 500°C in steps of 50°C; the coolant inlet temperatures were 10°C, 20°C and 40°C with a mass flow of 1L/min/cartridge, 2L/min/cartridge and 3L/min/cartridge.
Results of these measurements showed that the middle sector of the TEG tends to overheat and the bypass system has an increased gas leakage, which influences the energy output of the TEG system in a negative way.During the second experimental session at the engine test bench the TEG showed a very low performance (around 50% of the output power recorded during the first testing campaign), due to short-circuits between cartridges and external case, causing a dispersion of the generated current to ground and therefore it was replaced with a proprietary TEG (GEN4 - drawing n. TEG12-11595) supplied by Gentherm.
Electrification of components
An innovative multi-phase design of an electrical water pump and an electrical oil pump as 48V application was executed and then the 48V electronic approach was transferred to all other e-auxiliaries (e.g. alternator, e-hydraulic power steering, climate compressor, brake air compressor....); however the 48V electrification of the water-pump showed no energetic positive result, because the electrical production of energy as well as the
conversion to mechanical actuating power came along with electrical losses. Based on component behavior simulation it has been concluded that 48V is less cost efficient in comparison to 12V versions.
The simulation also showed that the electrification of the oil pump can be seen as a potential application for an
energy efficient powertrain solution, in fact over the ACEA cycle the energy balance of the electrified pump, under the condition of a lower pressure, is positive; nevertheless it was not implemented to give priority to the kinetic energy recuperation out of a belt driven starter generator, since the energy generated of the TEG and the Turbo-Generator is not even sufficient for the electrical base load (700W) for which reason an electrical generator is necessary.
Electrical Architecture with Storage System and PMU
Due to the need of energy harvesting and a high energy demand of the beltless engine concept a multi voltage architecture was set up which shows best performance to fulfill these requirements.
Taking into account the simulation results and the components specifications out of the consortium, to ensure the greatest possible flexibility and a high failure security a 48V and 24V main net and 12 V part net was set up inside the chosen E/E architecture.
Inside this concept the central regulation of the energy distribution takes over the Power Management Unit (PMU) which communicates via CAN-Bus with the electrical components.
The energy balance between the three nets (48V / 24V / 12V) was solved on the use of a 48V/24 DC/DC converter and a 48V/12 DC/DC converter. Therefore an efficient DC/DC converter was developed and implemented as multi stage approach to fulfil the need of the overall system.
An innovative e-storage concept was developed using a battery / DLC capacitor stack for 48 V board net level to deal with basic electric load coupled with the need of high energy peaks.
Then to ensure the failure security of 24V main net two 12 V AGM (Absorbent-Glass-Mat-Battery) are integrated, while to fulfill the requirement of energy harvesting out of recuperation during short time (fast energy storage) coming from the BSG a Double Layer Capacitor (DLC) was implemented into the E/E architecture; such a system gives the possibility to use the battery for storing the energy (e.g. provided by the E-generator or the TEG-generator) as base load and the DLC stack for high energy peaks (e.g. in case of drag moments of the e auxiliaries).
This e-storage system gives the options of transferring the energy in between the two storage systems according to overall system energy demand. In parallel, this approach is used for board net stabilization.
Subsystems control strategies development
Out of the overall E/E system design, the subsystem operation strategies for all e-components, including storage system of the beltless engine concept following typical heavy truck drive cycles demand were defined. Based on this operation strategy, a controller software was developed and implemented in E-system controller. A concept approval was done with a small test bench battery prototype, building up a dedicated E/E system test bench, to validate the subsystem control strategy.
Water Cooled Electric Supercharger and Turbo-generator
The COBRA C80 24V unit from CPT was chosen as the e-Booster, while the 48V Integrated Gas Energy Recovery System TIGERS from the same supplier was selected as turbo-generator.
Virtual power pack and system integration
Among the advanced innovative contents of the power pack, only the BSG is installed directly on the engine, replacing the normal production alternator.
The integration of the BSG had a deep impact on the engine auxiliaries driving belt system, requiring an accurate design of a brand new dedicated auxiliaries driving belt layout, pulley, double belt tensioner, for motor/alternator modes, and support on the crankcase.
A new Poly-V belt has been installed, while the standard production belt has been shortened.
In order to increase the efficiency and optimize the performance of the BSG, the latter has been connected to the low temperature coolant loop through dedicated water hoses.
Subsequently a complete packaging study was realized (CAD) to assess in detail the constraint and opportunities related to the integration of the GASTone power-pack at vehicle level.
Three other devices (TEG, TBG and e-Booster) are installed on the chassis; the virtual installation took into account all the constraints related not just to geometrical location, but also referred to the working condition of the vehicle equipped with the new concept engine.
The 3D model definition of the definitive subsystems themselves was the first step, than they all were integrated on the vehicle according to the following criteria:
- optimized engine behavior
- the optimization of the performance of the devices themselves
- Vehicle layout constraints;
- the device installation constraints given by the supplier/producer
- Regulation for CNG fuel systems.
The target was to fully implement the established schematic layout with the lowest possible impact on the normal production vehicle; the most modified subsystems of the n. p. vehicle were: the front radiator module, the air intake loop, the exhaust line and the fuel supply line.
A concept for the integration of the thermo-electric generator into the exhaust system, considering the optimal location of the TEG as well as the optimal performance of the exhaust system was developed, as well as a concept for the integration of the cold side heat exchanger of the TEG into a cooling system of the power pack. In order to maximize the available heat from the exhaust gas, the TEG integration on the new exhaust pipe line has entrained a major impact on the current vehicle layout; the TEG was installed as close as possible to the ATS outlet. According to specifications and once verified the best achievable performance with simulations, the TEG has been connected to the low temperature cooling loop. The fixing brackets were already available on the chassis, namely being those originally supporting the CNG tanks that needed to be moved away from that area in which both the TEG and TBG were installed; the TBG was installed directly downstream the TEG.
The TEG’s outlet goes directly to the TBG’s inlet port by a dedicated interface with a conical shape, creating a convergent pipe branch and causing a considerable increase of the pressure drop. The electric turbo generator (TBG) is a passenger-car derived component that was adapted to the current engine. The device is cooled down by connecting it to the high temperature cooling loop, according to CPT’s cooling specifications, parallel connected to the transmission oil cooler.
The e-booster (electric compressor) is a passenger-car derived component that was adapted to the current engine and is placed downstream the current air filter and upstream the turbocharger inlet in a separate air pipe to be by-passed when needed, by means of a dedicated by-pass valve that has been integrated in the standard production charge air pipe.
According to the supplier specifications, the integration required a new support bracket, connected to the vehicle chassis, that guarantees the correct impeller axle orientation and the suitable coolant connection positioning; the device is connected to the low temperature coolant loop.
This installation deeply modifies the charge air system layout: the blow-by and pop-off pipes have been moved before the e-Booster by-pass valve, in order to prevent the pressurized air from the e-Booster to go upstream these pipes routing, bringing about critical conditions for the engine performance. The installation of the device on the chassis allowed to decouple relative shaking between the engine and the component itself.
The n. p. cooling system is not designed to satisfy all the different requirements of the new users that, according to their specifications, need an optimized mass flow and working temperature range, that may be very different from those determined by the ICE operation: therefore a dedicated thermal management system with a new thermal module has been implemented; the new thermal module was designed taking into account the performance optimization activity carried out with dedicated simulations, and has been fully integrated in the virtual layout.
The low temperature (LT) cooling loop handles the heat rejection by the e-booster, TEG, BSG and WCAC (Water Charge Air Cooler); all the devices in the LT cooling loop have been connected in parallel with a dedicated brand new conveyor. The implementation of such a dedicated thermal system required the introduction of:
- A new LT radiator in the front module;
- A new dedicated coolant tank;
- Two dedicated conveyors;
- A 12 V electrical pump.
All the electronic devices dedicated to the electrical power management, storage and control (DC/DCs, dual layer capacitor – DLC - and control unit) were installed inside the longitudinal members of the chassis, in the rear of the vehicle, with no impact on the rear part of the chassis that would involve the reduction of the available cargo volume.
All clearance prescriptions have been complied with, according to internal design standards.
System physical integration and experimental validation
A 6 cylinders CNG engine was equipped with e-auxiliaries and mounted at test bench after metrological measurements for configuration sign off.
Afterwards new engine components were integrated together with control system to manage e-devices.
The Engine characterization in current production configuration in terms of performance, fuel consumption, emissions, heat rejection, friction and pumping losses and turbocharger performance (boost, flow rate) was performed.
After characterization of the baseline and engine updating with e-devices, the characterization and validation of the new adopted technical solution was performed as follows:
- Behavior measurement of e-water pump and calibration of related control management.
- Calibration of e-boost.
- Full comprehensive calibration of all e-devices.
Since a new thermoelectric generator type was introduced to replace the previous TEG setup, which was damaged due to short-circuits between cartridges and the external case, causing a dispersion of the generated current to ground, two different TEG prototypes were tested: the new TEG Gen4 demonstrated a better efficiency, even more without an external by-pass valve, which was necessary for operation of the first proto.
- Engine characterization with updated configuration in terms of performance, fuel consumption, emissions,
heat rejection, friction and pumping losses and turbocharger performance (boost, flow rate).
The measurements were done at fixed point representative of relevant engine speed/load of real mission and then a dynamic behavior was assessed at dynamic engine bench test according to WHTC and real life conditions (ACEA cycle).
The experimental validation was intended to assess the benefit of GASTone power pack in increasing vehicle/engine efficiency, during both steady-state condition and real life conditions (ACEA cycle).
The first validation testing activity was carried out with the aim to validate the e-Booster only.
The base engine, with the e-Booster installed in the air inlet line, was assessed on the ACEA reference driving cycle, in terms of inlet/outlet pressure upstream the current turbocharger and in terms of e-Booster power absorption, considering its impact on fuel consumption; some benefit on time to torque reduction has been verified, but with a negative effect on fuel consumption, due to electrical absorption.
The second validation testing activity was carried out with the aim of validating the TEG (Gen4 -2 modules in series) only. The Thermoelectric Generator (TEG) was preliminary assessed in terms of electrical power output on engine map and then the base engine, with the TEG installed in the exhaust line, was assessed during the ACEA reference driving cycle, in terms of backpressure increase and in terms of TEG energy production, considering its impact on fuel consumption: TEG effect on backpressure is limited, then negligible effect on fuel consumption is measured.
The third validation testing activity was carried out with the aim of validating the configuration with the TEG and the TBG. The base engine, with the TEG and TBG installed in the exhaust line, was assessed during the ACEA reference driving cycle, in terms of backpressure increase and in terms of electrical energy production, considering their impacts on fuel consumption: the addition of TBG causes an high backpressure increase that in its turn leads to a fuel consumption increase.
The fourth validation testing activity was carried out with the aim of validating the configuration with the BSG, with the presence of the TEG in the exhaust line. The base engine, with the BSG integrated on engine and the TEG installed in the exhaust line, was assessed during the ACEA reference driving cycle, in terms of BSG energy production and in terms of energy absorption, considering their impacts on fuel consumption also: when battery state of charge is > 50%, BSG can be used as motor and fuel consumption reduction is achieved.
Different strategies of energy recuperation were tested for the BSG, confirming that the most efficient one is to
have the BSG produce energy during deceleration periods (fuel cut-off) of the reference ACEA driving cycle, because of the friction increase during electrical energy production; the BSG efficiency was assessed to be around 60-70%, depending on the engine speed.
Benefit estimation at vehicle level and applicability study on diesel engine
An applicability study was carried out using the dynamic model of the engine and its energy balance.
The analysis considered at first only CNG engine while in a second phase the benefit and limit of a diesel GASTone power pack was also assessed.
The total electric production generated by the TEG, TBG and KERS was estimated: the KER in deceleration periods is the main producer while the TEG and the TBG contribute to the system approximately in the same percentage; the most important electric consumers are the pump of the high temperature cooling loop and the oil pump, followed by the accessories consumption, accounting in the whole for 90% of the total electric consumption.
The best combination apparently is the BSG system used as a producer as well. Nevertheless, the combination of the KERs system with the TEG and TBG results also very attractive being able to achieve a considerable fuel saving rate.
Each single device alone or even the combination of the TBG with the TEG do not generate enough electric energy to supply the auxiliaries, the same applying to the BSG in deceleration periods only.
In the investigated case, the average gas mass flow in the Diesel engine resulted to be double than in the CNG engine. Among the inquired technologies, the generation of electricity by the TBG is controlled by the mass flow as the dominant variable and therefore this latter technology is likely to be more adequate to Diesel engine applications.
In this case, the average temperature over the cycle by the CNG engine is 22% higher than by the Diesel engine, this latter being around 300ºC lower than by CNG engines. Therefore, recovery technologies which control factor is the temperature, as the TEG, show a greater potential in CNG engines.
Therefore, from the point of view of potential energy recuperation, the quality of the wasted thermal energy of the exhaust gas is lower in Diesel engines. The consumption share of the electrified auxiliaries remains very similar to the one observed in the CNG engine. Nevertheless, in this case the highest consumer is the electric oil pump, while the high temperature water pump requires less water mass flow through the cooling loop thanks to the lower combustion temperatures of the DIESEL engine, resulting in a lower consumption by this component.
The maximum fuel saving along the ACEA cycle is 18% lower for Diesel engines than for CNG engines for the GASTone proposed configuration.
In conclusion the most versatile technology used in the GASTone approach is the BSG system, able to produce electricity at any time ensuring the availability of the electricity even though it is not always for free.
The new generation TEG does not have a high temperature limitation as the old generation but its power production generate is lower result than expected at the beginning of the project but still very interesting for its application.
The TBG shows the highest potential for energy recuperation, however, it causes too much backpressure on the engine side. Therefore, only upon solution of this issue, this technology would definitely turn out to be one of the most promising and cost-effective.
Cost and investment estimation
The GASTone engine system was analyzed as well as its on-board integration so to split the costs per function and to estimate the overall cost, based on different market scenarios (1000 vehicles/year vs. 5000 vehicles/year); to this purpose a complete and detailed bill of material was defined of the GASTone system taking into account mechanical fitting, piping and wiring, besides the major components, adding also the normal production vehicle and engine interfaces.
Once defined the BoM, the costs of each item has been evaluated in terms of variable costs and investments.
Make or buy elements were classified in different categories: in the first case it was also necessary to evaluate the investment costs related to the dedicated workstations, required at the vehicle assembly line for the completion of semi-finished products delivered by suppliers.
The cost issue was considered both from user point of view and industrial point of view taking into account direct costs as well as indirect costs; the production, usage, maintenance and dismantling related cost were be also considered in the frame of the estimation of the total cost of ownership and the dismantling issue was also included. The TCO estimation represents the overall expenditure, including both fixed and variable costs, from the one-off purchase price of the vehicle, to the annual operational expenses, up to the reuse/recycle/landfilling of the dismantled vehicular components.
In the GASTone project, the TCO estimation has been carried out with the purpose to compare the current production heavy duty truck IVECO Stralis Natural Gas Euro VI to the same vehicle updated with all the new GASTone technologies, resulting that the purchase cost of GASTone concept vehicle would be significantly higher than a comparable heavy-duty NG Euro VI vehicle.
The annual maintenance and repair cost of the GASTone vehicle is estimated as slightly higher than current NG vehicle, due to the installation of new components that are not present in the current vehicle.
Fuel cost is consistently the highest driver of the TCO calculation and it is addressed by the adoption of the GASTone technologies. The simulation model developed by the Polytechnic of Valencia predicts a fuel reduction during the ACEA cycle and this fuel consumption reduction means a lower expense on annual fuel cost. The taxes, insurance, tolls referred to the GASTone vehicle are assumed equal to the current one, since it is uncertain if in the near future the legislation could reward the vehicle with a waste energy recuperation system. The payback time of the incremental cost strongly depends on the fuel consumption reduction in comparison to the reference vehicle and its annual mileage. The business case, based on a mileage of 120 000 km/year, shows a not favorable payback time.
System technology feasibility
The system technology feasibility of the GASTone system has been demonstrated taking into account all the impacts that the introduction in a series production vehicle reflects.
A risk assessment wasbe carried out to identify any potential issue that might become a barrier for the desired implementation of GASTone system and A SWOT analysis (strength, weakness, opportunities and threads) was carried out, aimed at identifying the internal and external key factors influential to the successful achievement of the project’s targets. The following risk drivers have been identified:
- Customer Expectation Risk:
o Subsystem/ Component Content.
o Customer Usage.
o Functional Objectives.
o Reliability/Quality Prediction.
- Technical Execution Risk:
o System Interaction.
o Design Practice.
o Core Documents Integrity.
o Validation Testing.
o Vehicle Diagnostic Capability.
- Program Risk:
o Supplier Sourcing.
o Program Timing.
The risk can be evaluated as:
- High, if the component is brand new or a first application.
- Medium, if the specific application can be handled according to already available experience.
- Low, if the component is a carry over or a consolidated and already known technology.
Based on the output of the risk analysis and the SWOT analysis a system validation plan and a Risk Mitigation Plan were be generated. This plan resume all the mitigation actions needed to properly handle and reduce the risk down to the lowest level possible, with the indication of the begin and the ending of the activity required.
According to the project’s purpose and limitations the consortium agreed to edit the mitigation plan only for the components and systems that were rated with an HIGH risk, this means that the plan have to be integrated and completed in case of industrialization of the system.
The object of the SWOT analysis (strength, weakness, opportunities and threads) aimed at outlining the strengths of the GASTONE efficient power-pack to be leveraged in view of a possible industrialization phase of the relevant technologies to ensure its successful introduction into series production.
Even more, the intrinsic weaknesses of the developed system are investigated in order to anticipate any unsolved issue or open point which might hamper the penetration of the GASTONE enhanced power pack in the market, because of a lack of economic sustainability or insufficient reliability or simply because of a low acceptance of its novelty by the final customers.
Threats arising because of a changing legislative and regulatory scenario, competition from alternative emerging or better established technologies which might hinder the extensive adoption of the GASTONE approach in massive production are also taken into consideration, with the purpose of contributing to remove every possible road block towards the achievement of the sale of more efficient and cleaner power trains.
The same applies to the competing environment represented by alternative transport modalities and different options in long distance freight transportation which might be gaining ground, based on economic and environmentally related reasons.
The SWOT analysis has been executed by means of several brain storming sessions held separately at both CRF and FPT with different discipline specialists on the basis of internal know how and experience, then the related outcomes have been integrated into a single matrix; in CRF the brainstorming sessions were leaded by an expert in innovation methodologies in the role of facilitator.
The system key properties were grouped in the following main categories for internal or external factors:
• System layout interactions & controls.
• Production & service.
• Novelty & maturity.
• Innovative technology introduction in current vehicle.
• Dismantling.
• Verification & validation concepts.
• Market.
• Legislation.
• Economics.
• Supplier chain.
In the end it was reckoned that the GASTone system has a great potential for environmental and economic sustainability increase of the long haulage freight transport, which could make it an attractive and
successful product on the marketplace.
Nevertheless its introduction into series production would require managing and overwhelming the issues originated by its relatively high complexity and the important costs required by the technical and technological efforts and the associated capital investments.
The competition from other freight transport modalities (waterborne and railway mostly) and the general macroeconomic scenario, together with the changing legislative framework, add to the uncertainty surrounding the success chances of the initiative, which pay back to the OEM still needs to be demonstrated.
Potential Impact:
The project GASTone has substantially achieved its expected results, having accomplished the design, development, prototypal construction and testing at the dynamic bench of an enhanced CNG power-pack for a long haulage heavy commercial vehicle.
The final testing has singled out some limitations in the operation of the overall GASTone system, which hampered the achievement of the efficiency gain originally expected, mostly due to an increased counter-pressure caused by the turbo-generator, entraining a higher fuel consumption (BSFC) over the ACEA driving cycle, which being a standard component available on the market couldn’t be conveniently sized to match the engine displacement and power. Nevertheless the feasibility of harvesting and storing free electrical energy by means of the waste heat recuperation approach was demonstrated and the design of a suitably dimensioned turbo-generator would be a straightforward engineering problem.
However the most promising configuration - in terms of fuel consumption reduction – proved to be without the turbo-generator and the e-booster, since any benefit in using the e-booster is a reduction in turbo lag effect and time to torque, at the expense of an even higher fuel consumption increase associated with an electrical energy absorption.
The thermo-electric generator offers good potentials for energy production with negligible effects on fuel consumption, thanks to low counter-pressure.
The best performing strategy for the kinetic recovery system (BSG) proved to be producing electrical energy during deceleration periods and when the battery state of charge is < 50%; when the battery state of charge is > 50%, the belt starter generator (BSG) can be used as motor granting a fuel consumption reduction, which is achieved during the first 1500 seconds of the ACEA cycle.
In the whole during the project several different technologies aimed at improving the long haulage truck efficiency could be developed and assessed and the holistic approach to the engine and powertrain energy management could be explored.
Simulation tools to support the development of the system management and control strategies and the evaluation of the adaptation of such a system to the various power trains were designed and implemented.
The different technologies aimed at the production of decarbonized energy, by the re-use of the waste energy, researched during the project will have a significant and positive impact on the long distance truck energy efficiency and CO2 emission reduction, irrespectively whether they will be applied either severally or integrated into a last generation CNG engine and in combination with electrified auxiliary systems to implement the beltless engine concept and to realize an highly efficient power pack.
In fact, despite Diesel engines having long been the most applied solution in the road transport sector for their high efficiency and power, and being expected to remain the dominant fuel for commercial vehicles beyond 2020, thanks to the availability of large worldwide reserves, natural gas benefits from more favorable and stable pricing, resulting in lower fuel costs and making it a truly viable alternative to Diesel.
Considering that the fuel burnt in a natural gas engine mainly consists of methane and that several countries in
Europe use bio-methane together with natural gas, and taking into account bio-methane life cycle emissions with its CO2 closed cycle, it’s clear that bio-methane proves to be a carbon neutral fuel.
The production potential for bio-methane is very significant, and would allow thousands of de-carbonized vehicles, fossil fuel-free driving resulting in a neutral carbon footprint.
Moreover synthetic gas is generated via gasification of surplus electricity (wind or solar), where renewable electricity is converted into hydrogen (through electrolysis) and then, by adding CO2, into synthetic methane.
As heavy-duty vehicles account for roughly 5% of Europe’s greenhouse gas emissions, assuming that 10% to 20% of the methane mix will come from renewable sources (bio-methane and power-to-gas) by 2030, when natural gas will account for over 26% of global energy demand, total reductions of up to 70% in CO2 emissions should be achievable compared to conventional vehicles, making methane the most cost-effective way to reduce CO2 from transport in the short to medium term.
The heavy-duty vehicle manufacturers contributed 550 billion € in gross value added (GVA) to the European economy in 2011; moreover, heavy-duty vehicles generated over 5 billion € trade surplus for the European Union in 2014.
In 2015, more than 350,000 heavy commercial vehicles were produced in the EU, and over the first three quarters of 2016 EU exports of light and heavy commercial vehicles summed up to around 7.6 billion €.
All the above statements give a precise dimension of the importance for the EU economy to keep its commercial vehicle sector highly competitive worldwide by the introduction of more efficient technical advanced products into the marketplace.
Rising manufacturing costs and greater utilization of rail networks (especially high-speed rail and inland waterborne transport ) are likely to exacerbate OEM competition even more in the future.
Therefore demand for low-cost trucks is expected to increase in medium- to long-term, fostering Turkey, India, Russia, and Indonesia as major low-cost manufacturing platforms.
Since the opportunities offered by the developed advanced technologies and their integration into a single system under a central control to implement optimized operation strategies are also pointed out as a possible unique selling product, comprising high added value and extending the OEM’s product range to compete on the global marketplace, the development of the concepts proposed in GASTOne provides many chances for the European industry to remain competitive and to gain market share in the area of technologies for energy efficiency in road vehicles. European vehicle manufacturers will be able to produce vehicles that meet exacting standards for energy efficiency whilst retaining the attributes of safety, comfort and performance that make European vehicles attractive to purchasers worldwide.
IVECO is predicted to take advantage of its China-based platform strategy, especially in South American and African markets, with China-made SAIC-IVECO trucks targeted to reach 65% of their total African sales.
While engine platform development is still focused on diesel engines, the rapid introduction of natural gas as heavy duty truck fuel (more than 8% penetration in new trucks by 2022) is boosting global natural gas engine development.
FPT developed a proprietary multi-point CNG engine for low consumption that meets Euro VI/EPA 10 and adopted a zeolite-based unique Selective Catalytic Reduction (SCR) technology to achieve Euro VI emission standards; without EGR, SCR or particulate filters, the latest generation Cursor 8 CNG Euro VI engine requires no additive and is 100% compatible with bio-methane. Thanks to its particularly efficient "stoichiometric" combustion, its pollutant emissions are much lower than those mandated by the Euro VI Directive as of 1st January 2014, with significantly less fine particulate matter and NO2 which are responsible for respiratory diseases in urban locations.
FPT, will exploit the outcomes of GASTone at first to strengthen its leadership in the domain of heavy duty CNG engines and then to improve the competiveness of the diesel engine range offering the opportunity to originate new innovative products.
Of all emissions standards, Euro VI had the greatest impact on vehicle design, as it required combining a high number of technologies in order to achieve near-zero levels of emissions.
IVECO overcame this challenge with a unique breaking through solution with no exhaust gas recirculation (EGR) for its whole range of trucks from 7.5 to 50 t Global Vehicle Weight.
Entrusting the entire anti-emission process to the HI-SCR system , IVECO escaped the trend for increasing complexity of diesel engines, while improving reliability and, ultimately bringing reductions in the Total Cost of Ownership (TCO).
Since the late 90s, IVECO has developed a wide range of engines, ranging in power from 136 hp to 330 hp, that run either on natural gas or bio-methane (in its renewable version), whether compressed to 200 bar (CNG) or in liquid form at -130°C (LNG). Twenty years of experience builds IVECO's status as leader in alternative natural gas-powered propulsion, with more than 24,000 engines produced.
Nowadays, since FPT acts as the major engine/powertrain components product development and supplying partner for IVECO trucks, the strong relationship of FPT with IVECO will allow to exploit the results in the domain of large truck and medium commercial vehicles with the overall goal to reduce CO2 emissions and fuel consumption and to increase vehicle fuel economy.
Furthermore, the concept of an integrated thermal system and the use of the thermal energy in rational way based on advanced components and sophisticated algorithms provides many global business opportunities for the European component supply industry thus further contributing to European competitiveness.
From the beginning of the project a website was made available and continuously updated throughout the project in order to diffuse basic information of the project (e.g. objectives, partners, publications...).
Moreover the project results were published in the automotive sector and scientific community along the whole project duration, disseminating them in the most relevant events of the automotive industry.
Following presentations were given:
“GASTone: New Powertrain Concept based on integration of Waste Energy Recovery, Storage and Re-use”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi, Daniela Magnetto
European Conference - Thermal Systems and Aerodynamic Solutions for Ground Vehicles – Trends and Challenges for New Levels of Comfort and Energy Efficiency ATA – Associazione Tecnica dell’Automobile, Torino June 17th – 19th 2015.
“Development of a new powertrain concept based on the integration of electric generation, energy recovery and storage”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi, Daniela Magnetto
“Model of a new powertrain concept based on the integration of electric generation, energy recovery and storage”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Corberán Salvador, Alex Rinaldi, Daniela Magnetto
International Conference and Exhibition on Automobile Engineering, Valencia September 1st – 3rd 2015
“GASTone: Nuova concezione di propulsione basata sull’integrazione dei sistemi di recupero e riutilizzo dell’energia”
E. HERVÁS-BLASCO, E. NAVARRO-PERIS, J.M. CORBERÁN, D. MAGNETTO, A. RINALDI
Giornata di Studio Tecnologia Termoelettrica per il Recupero di Calore Disperso - Fondamenti e Applicazioni, Milan October 8th 2015
“Dynamic Model of a New Powertrain Concept Based On Energy Recovery from Exhaust Gases and Kinetic Losses to Electrify the Main Auxiliaries Oriented To Reduce Fuel Consumption”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi
“ GASTONE: New Powertrain Concept for CNG Engines”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi
SAE World Congress & Exhibition, Detroit (MI) April 12th – 14th 2016
“GASTONE – Development of a New Powertrain Concept Based on the Integration of Electric Generation, Energy Recovery and Storage Efficiency”
Alex Rinaldi, Alberto Maria Merlo, Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador
6th Transport Research Arena Warsaw, April 18th - 21st 2016.
“Optimal configuration of a thermoelectric generator to recover wasted heat”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador
VIII Congresso Ibérico – VI Congresso Ibero-Americano – Ciencias E TECNICAS DO FRIO
May 3rd – 6th 2016 Coimbra, Portugal.
“Gastone: an integral approach to maximize efficiency in heavy duty CNG engines”
Alberto Maria MERLO, José M. CORBERAN, Stefano GOLINI, Shaun MCBRIDE, Roland ÖLLER, Andreas SCHIESSL
CO2 reduction for Transportation Systems ATA - SAE Conference in Turin on June 29th - July 1st 2016.
“GASTone: an integral approach to maximize efficiency in heavy duty CNG engines”
Alberto M. Merlo, Alex Rinaldi, Stefano Golini, Francesco Tucci, Rainer Gietl, Andreas Schiessl, Estefania Hervas Blasco, Emilio Navarro Peris
EGVIA workshop on Heavy-Duty Vehicles held in Brussels on May 31st 2017.
In the whole the project has been presented in 9 International Conferences with a total of 12 contributions in 6 different countries, including the United States of America.
A special session dedicated to the GASTone project was organized within the International “Congress on Transport Infrastructure and Systems (TIS)” held in Rome by the Italian Association for Traffic and Transport Engineering in the headquarters of the “Automobile Club d’Italia”, on the 12th of April 2017.
Eleven presentations were given, reflecting the work-package brake-down structure and summarizing the most meaningful results of the project.
Besides the training of young engineers and scientists, and in the dissemination of the project in the academic sector
Two workshop sessions addressed to the students in the UPVLC were given on April 28th and May 12th 2016:
1. Next technologies to increase the efficiency of heavy duty vehicles. Un ejemplo de ingeniería integral
Speakers: Estefanía HERVAS-BLASCO, Emilio NAVARRO-PERIS, José M. CORBERÁN
Conference given at the UPV as a training for new engineers and scientists form the mechanical, electronic, electric, automatic engineers on April 28th 2016.
2. Next technologies to incresase the efficiency of heavy duty vehicles. An example of integral engineering
Speaker: José M. CORBERÁN
Conference given at the UPV as a training for new engineers and scientists form the Energy, Chemical, industrial organization and industrial engineers on May 12th 2016.
An introduction of the main objectives and achievements of the project GASTone was given on March 28th 2017 to FCA Product Development engineers during the professional training “Corso PD Architetture elettriche modulo 1 - i veicoli ibridi” (Electric Architectures module 1 – Hybrid Vehicles).
Gentherm presented a stand at the IAA Commercial Vehicles 2016 exhibition in Hanover (Germany) on the 22nd- 29th of September in 2016.
A screen with the project presentation was placed in the stand, thus disseminating the existence of the GASTone project within a commercial automotive sector.
The exploitation plan for the commercial exploitation of the scientific and technical results was developed.
As automotive research and innovation center, CRF works on different technologies in order to jointly achieve the fuel economy targets and environmental sustainability goals, consistently with the standards in force and by the expectations of the wider society, which are the R&D major drivers in current product development, in the field of passenger cars.
In particular waste heat recovery is one of the topic in which CRF is investing its efforts and the thermo-electric generation is one of the technologies investigated.
Therefore CRF aims at consolidating its knowledge on thermal and kinetic energy recovery systems in order to foster the development and design of a series of devices to be installed on different applications, accordingly with the company mission of its parent company FCA to widely implement these technologies in passengers cars.
Moreover the GASTONE project is interesting for CRF, having allowed to investigate several other implemented technologies such as the 48V electrical architecture and the electrification of different auxiliaries, in particular the electrical coolant pump for the dual level cooling system and in replacement of the mechanical engine coolant pump.
The higher power level of these auxiliaries means a higher specific performance and efficiency, staying in a voltage range not requiring any galvanic insulation of the specific electric board-net, which would be needed for voltages higher than 60V.
Engineering Center Steyr GmbH & Co KG (ECS) is a world leading engineering service provider for development and engineering, in the following areas:
- Commercial vehicles
- Powertrain systems
- Non-road-mobility
- Alternative mobility and transportation
- Thermal management
- Railway systems
- Fluid and pressure technologies
- Sports cars
- Leisure and marine vehicles
- Technology & software
- And system integration.
The main interest of ECS regarding the GASTone program is to become an engineering partner providing a complete service of TEG system and components integration from concept to series application, by the integration of TE modules to get a complete TEG system.
Opportunities for using the gained knowledge during the program will be:
- Development of simulation models for optimal TEG system sizing
- Integration of TE modules available on the market
- Application of TEG systems on gas powered commercial vehicles:
- Testing of TEG systems on engine test bed and on complete vehicles:
- Development of DC/DC converter for high current and low voltage area.
- Development of a TEG control unit as MPPT (maximum power point tracker) including control of bypass systems to provide an intelligent TEG system component.
- Development of an overall TEG system operating strategy.
Due to a strategic shift in the scope of MAGNA as parent company, ECS is focusing more on passenger cars than on commercial vehicles in the future.
GENTHERM designs, develops and markets innovative thermal management technologies based on advanced, proprietary, efficient thermoelectric device technologies for a broad range of global markets and heating and cooling and temperature control applications.
GENTHERM’s advanced technology team is developing more efficient thermoelectric materials and systems for waste heat recovery and electrical power generation for automotive, industrial and other markets.
With approaching global requirements for vehicle carbon emissions and calls for cleaner vehicles, the Thermoelectric Generator (TEG) is at the technological forefront as a solution for meeting changing market demands.
Focusing on the development of advanced, high temperature, scalable thermoelectric modules, GENTHERM are driven to cement their position as the world’s leading supplier of high performance integrated thermoelectric modules for power generation. The benefit of the proprietary knowledge and know-how developed during the GASTone project is twofold, in that it helps to further GENTHERMs’ opportunities to develop and engage in the heavy duty market, while also analyzing the potential for thermoelectric power generation in CNG applications.
The knowledge gained will be used in future projects examining heavy duty applications as well as passenger vehicle and light commercial vehicle applications to provide further optimized and improved technical and economical solutions.
Since IVECO (CNH Industrial group) is very well positioned in LNG/CNG market, in all vehicle segments, the market entry is a very crucial point and has to be correctly exploited to reach the maximum impact and to possibly increase the actual sale volumes of long haul truck.
FPTI plan for the exploitation of the GASTone project results is a roadmap towards full implementation of the concept within 2020, bringing the technologies through to series production after having completed the industrialization of new systems in the Cursor Natural gas engines: the main marketing message would be
- The availability of an innovative product for the existing market of fleet operators
- The confirmation of the advanced energy recovery approach combined with a reduced fuel consumption, focusing on the reuse of the waste heat of exhaust gas and the partial kinetic energy recovery
Main goals to be reached and communicated would be:
- Engine improved performances
- Turbo-lag reduction (with e-booster implementation)
- Fuel saving (thanks to BSG contribution as a motor).
With its innovative products, Continental helps vehicle manufacturers to meet regulatory requirements, which are stricter in the field of commercial vehicles than anywhere else. That`s how the company is paving the way for tax benefits or reductions in road use fees for especially clean vehicles.
When developing components for commercial vehicle drive systems, Continental focuses on profitability for fleet operations and offers various solution strategies and existing technologies around the world, in order to fulfill the goals of the markets as needed.
The propulsion and energy system investigated within the GASTone project plays an important role to clarify how far electrification and energy recovery will penetrate the commercial vehicle market. Potential savings in fuel consumption and subsequent CO2 emissions are known to be strongly dependent on system efficiency and energy losses within the primary and secondary propulsion and powertrain components. In particular, the energy management and board net (based on 12V/24V/48V multi-level voltage) has been proven to be crucial for efficient energy generation, distribution and partitioning of the whole system. Therefore, Continental is developing a specially tailored power management unit to monitor, control and distribute electrical power flows within the complex E/E architecture.
In addition the electrification of the oil-pump is seen as benefitting CO2 reduction at system level. That´s why Continental is considering to start developing such an auxiliary for commercial vehicle application.
The development of this multi voltage E/E architecture will allow to implement in a next step newly developed even bigger auxiliaries with significant participation of electric power consumption (>1kW peak), e.g. AC-compressors, e-Booster or bigger liquid pumps.
One key role for fulfilling the need of CO2 reduction within the new developed multi voltage approach in GASTone is played by a belt starter generator, which will act as major contributor on the energy generation side. Peak performance of more than 12kW can be handled efficiently only within a 48V stage, in combination with DLC (double layer capacitor) and rapidly controlled DC/DC converter. Therefore these components are in focus for future developments and potential products that could be provided by Continental to commercial vehicle OEMs.
Control strategies as well as energy generation, consumption, storage and distribution of electrical power have been developed and advanced during Continental´s contribution to this project and will be further in future. Results and performance potentials will enter future product developments and facilitate functional assessment of emission-optimized powertrain systems. Such systems will furthermore enter the multi-voltage as well as the single-voltage board stages for commercial and passenger vehicles under consideration of the GASTone project results and the current research of the consortium partners.
List of Websites:
http://gastone-project.webs.upv.es/
Alberto M. Merlo
Senior Specialist Public Funding
Interiors Systems Department
Vehicle Research & Technologies
C.R.F. S.C.p.A.
Corso Luigi Settembrini, 40
10135 Torino, Italy
Tel. +39 011 00 42 7 24
ALBERTOMARIA.MERLO@CRF.IT
Sede legale e amministrativa, Strada Torino 50
10043 Orbassano (TO), Italia
The final goal of the project GASTone has been the high efficient energy conversion for a natural gas heavy duty engine, namely the FPT Cursor8 NG Euro VI installed in the IVECO Stralis NG Euro VI MY2014.
The energy recovery strategy is based on two mainstreams:
• Recovery of a portion of the kinetic energy thanks to the adoption of a belt driven generator (BSG).
• Recovery of the waste heat with an energy cascading approach: thermoelectric generator operating at high temperature (TEG) and a subsequent turbo-generator (TBG).
The Project most important outcome has been a new powertrain concept based on a combined energy recovery, storage and re-use system integrated and optimized with the engine system and controls.
The above mentioned functions were integrated into a multilevel board net architecture, created comprising e-auxiliaries, e-generation and energy storage, with a central control unit integrating all control and power electronic, to achieve an effective, overall electric energy management within a beltless engine concept.
The operation strategies for all e-components, following typical heavy duty truck drive cycles demand were defined and a control software was developed and implemented into the e-system controller.
In the end the experimental activity enabled the bench testing of both the reference engine and the GASTone power pack; the 6 cylinders CNG engine was equipped with e-auxiliaries and mounted at test bench after metrological measurements for configuration sign off. Afterwards new engine components were integrated together with control system to manage e-devices.
The engine characterization in n. p. configuration and in GASTone configuration was executed in terms of performance, fuel consumption, emissions, heat rejection, friction and pumping losses and turbocharger performance (boost, flow rate), the measurements were done at fixed point representative of relevant engine speed/load of real mission and then a dynamic behavior was assessed at dynamic engine test bench according to WHTC and real life conditions (ACEA cycle). The results yielded by the experimental activity were the basis and input data for the benefit estimation at vehicle level and applicability study on a diesel engine, carried out using the dynamic model of the engine and its energy balance developed at the beginning of the project.
The total electric production generated by the TEG, TBG and BSG was estimated: the BSG in deceleration periods is the main producer while the TEG and the TBG contribute to the system approximately in the same percentage; the best combination apparently is the BSG system used as a producer as well. Nevertheless, the combination of the BSG system with the TEG and TBG results also very attractive being able to achieve a considerable fuel saving rate. In the investigated case, the average exhaust gas mass flow in the Diesel engine resulted to be double than in the CNG engine. Among the inquired technologies, the generation of electricity by the TBG is controlled by the mass flow as the dominant variable and therefore this latter technology is likely to be more adequate to Diesel engine applications. In this case, the average temperature over the cycle by the CNG engine is 22% higher than by the Diesel engine. Therefore, recovery technologies which control factor is the temperature, as the TEG, show a greater potential in CNG engines.
In conclusion the most versatile technology used in the GASTone approach is the BSG system, able to produce electricity at any time ensuring the availability of the electricity even though it is not always for free.
The GASTone engine system was analyzed as well as its on-board integration so to split the costs per function and to estimate the overall cost, based on different market scenarios; the cost issue was considered both from user point of view and industrial point of view taking into account direct costs as well as indirect costs.
In the GASTone project, the total cost of ownership was evaluated with the purpose to compare the current production heavy duty truck IVECO Stralis Natural Gas Euro VI to the same vehicle equipped with all the new GASTone technologies, resulting that the purchase cost of GASTone concept vehicle would be significantly higher than a comparable heavy-duty NG Euro VI vehicle, resulting in a not favorable payback time.
Project Context and Objectives:
The heavy-duty vehicle manufacturers are a paramount chain link of an efficient freight transport in Europe, with the sector generating over 5 billion € trade surplus for the European Union in 2014.
In 2015, more than 350,000 heavy commercial vehicles (HCV) were produced in the EU, more than 150,000 of which in the countries participating to the project GASTONE, while over the first three quarters of 2016 EU exports of light and heavy commercial vehicles summed up to around 7.6 billion €, generating a trade surplus of about 2 billion €.
Trucks are economic goods, what makes fuel efficiency a key element in the purchase decision; because of the competition among freight transport service providers, final customers will continue to be very sensitive to indirect costs and will be interested in technologies that help reduce operative costs and Total Cost of Ownership (TCO).
Fuel, reaching 30% of the running costs in the transport sector, is one of the most important competitive factors in the heavy-duty vehicle market.
With the annual average travelled distance likely to remain above 100,000 km, the introduction of a new-generation of fuel-efficient engines and trucks is expected to improve fleet efficiency, thereby contributing to curb fuel costs.
Thanks to the availability of large worldwide reserves, natural gas (LNG/CNG) benefits from favorable and stable pricing, resulting in lower fuel costs and making it a truly viable alternative to Diesel fuel.
Carbon soot, NOx, and GHG emission reduction and fuel efficiency enhancement will drive global regulations, both Euro VII and EPA until year 2025, thus EU VI and potentially EU VII compliance and lifecycle cost are expected to remain a serious concern for fleets in the close future.
Of all emissions standards, Euro VI had the greatest impact on vehicle design, as it required combining a high number of technologies in order to achieve near-zero levels of emissions.
IVECO overcame this challenge with a unique breaking through solution with no exhaust gas recirculation (EGR) for its whole range of trucks from 7.5 to 50 t Gross Vehicle Weight.
Since the late 90s, IVECO has developed a wide range of engines, ranging in power from 136 hp to 330 hp, that run either on natural gas or bio-methane (in its renewable version), whether compressed to 200 bar (CNG) or in liquid form (LNG) at -130 °C.
Twenty years of experience built IVECO's status as leader in alternative natural gas-powered propulsion, with more than 24,000 engines produced.
FPT Industrial developed a proprietary multi-point CNG engine for low consumption that meets Euro VI/EPA 10 standards and adopted a zeolite-based unique Selective Catalytic Reduction (SCR) technology to achieve Euro VI emission standards; without EGR, SCR or particulate filters, the latest-generation Cursor 8 CNG Euro VI engine requires no additive and is 100% compatible with bio-methane. Thanks to its particularly efficient "stoichiometric" combustion, its pollutant emissions are much lower than those mandated by the Euro VI Directive as of 1st January 2014, with significantly less fine particulate matter and NO2 which are responsible for respiratory diseases in urban locations.
Entrusting the entire anti-emission process to the HI-SCR system, IVECO escaped the trend for increasing complexity of Diesel engines too, while improving reliability and, ultimately, bringing reductions in the total cost of ownership (TCO).
However, as Heavy-duty vehicles account for roughly 5% of Europe’s greenhouse gas emissions (GHG), with the future EU legislation on CO2 from trucks requiring a declaration of CO2 values for each truck produced based on all vehicles sold every year, natural gas is expected to achieve a noticeable penetration rate among different powertrain fuels, with CNG/LNG rapidly emerging as a key fuel expected to attain a global market share of up to 8.5% by 2022 when global sales are forecast to reach over 390,000 units.
Moreover, today not only natural gas engines, but also hybrid powertrain adoption is expected to increase in the years to come; at the same time downsizing, down speeding, in-cylinder improvements, reduction of friction losses, fast warm up and waste heat recovery are emerging as most important R&D topics for the next generation of powertrains, besides hybridization.
However when the project GASTone started in year 2013, full hybrid solutions of the powertrains for the heavy commercial vehicles were not feasible due to economic and technical constraints and consequently the research work was focused on the electrification of the auxiliaries with an outlook to an advanced starter generator solution with possible mild hybrid functions.
Turbocharging technologies will also play an increasing role in powertrain strategies as power density requirements in major commercial vehicle markets increase, demanding very high compression ratio, while electrically assisted turbocharging is effective in transient response.
In the end the project objectives have been pursued mainly through three different approaches:
1. The energy recovery from the exhaust gases heat with a cascade approach thanks to the adoption of an advanced thermoelectric generator and a turbo- generator.
2. The integration of a smart kinetic energy recovery system to substitute the alternator and generate decarbonized electric energy during decelerations.
3. The electrification and control of the main auxiliaries (coolant pump, auxiliary e-supercharger, etc.) by using the produced electric energy.
The above mentioned functions were integrated into a multilevel board net architecture, created comprising e-auxiliaries, e-generation and energy storage, with a central control unit integrating all control and power electronic, including a DC/DC-converter to achieve an effective, overall electric energy management within the beltless engine concept.
The operation strategies for all e-components, following typical heavy duty truck drive cycles demand were defined and, based on this operation strategies, a control software was developed and implemented into the e-system controller.
Furthermore, the thermoelectric generator (TEG) required specific integration into the exhaust system of the selected CNG internal combustion engine, minimizing any negative influences on the exhaust after-treatment and the pumping losses, on one side and the integration of the cold side heat exchanger into the engine cooling system on the other side, also considering the interaction of the thermoelectric generator and its produced energy with the power grid of the power pack.
In the end the experimental activity enabled the testing of both the reference engine and the GASTone power pack.
Project Results:
Reference engine, vehicle and assessment methodology definition.
The reference engine and vehicle were defined to be the FPT Cursor8 NG Euro VI installed in the IVECO Stralis NG Euro VI MY2014, and their working conditions and vehicle energy balance (fuel consumption thermal, electric,...) were identified in order to define a real world mission, which was chosen to be the WHTC and ACEA cycles.
A specific assessment procedure to show the improvement of the proposed GasTone Concept with respect to state of the art engine was defined. The main performance parameter chosen were the energy efficiency.
Model based system benefit estimation
A dynamic model of the system was developed, to simulate all the occurring interactions among systems, engine and vehicle and to estimate the electrical balance, the heat rejection demand and temperature levels and estimate the overall fuel economy.
The system concept design was drafted identifying the most promising configuration.
An advanced concept with a central control unit integrating all control and power electronic for each e- auxiliaries, generators and e-storage including a DC/DC-converter and an overall control strategy were established to ensure the energy efficient system operation management among e-generation, energy consumption and storage within the beltless engine concept.
The overall system architecture and the individual components were defined and sized and their technical specification identified. A smart board net architecture was created comprising e-auxiliaries, e-generation and storage using a beltless engine concept based of a 48-volt electrification.
Thermoelectric Generator (TEG)
Thermoelectric modules were combined in a system level design optimizing their positioning, orientation and configuration in the thermoelectric generator; the TEG consists of 32 cartridges which are electrically connected in series.
Since it is necessary to regulate the temperature and mass flow of the exhaust gas reaching the cartridges to avoid their overheating, a bypass system was implemented to reduce the overall exhaust gas flow into the TEG system, in case of high load operating points; the bypass was realized as a rotary valve; a control strategy for operating the bypass system and a power point tracker are developed and implemented in the TEG system.
Based on appropriate simulation models of the thermo-electrical behavior of the TEG modules, a Matlab/Simulink model was developed for the control of the TEG system.
Compiled software-models for the internal control of the TEG system were implemented onto rapid prototyping hardware (dspace-AutoBox).
The TEG system was validated on a functional test bench in terms of power output.
The functional test bench was designed to simulate the gas engine used in the project in terms of exhaust gas temperature and mass flow. As the engine has very high values of gas temperature and mass flow it was not possible to reach those maximum values with the functional test bench, the limits of the test bench being about 510°C gas temperature at 300kg/h mass flow, close to the design point.
The TEG system was functionally tested and the system validation was done with steady state points of 300°C up to 500°C in steps of 50°C; the coolant inlet temperatures were 10°C, 20°C and 40°C with a mass flow of 1L/min/cartridge, 2L/min/cartridge and 3L/min/cartridge.
Results of these measurements showed that the middle sector of the TEG tends to overheat and the bypass system has an increased gas leakage, which influences the energy output of the TEG system in a negative way.During the second experimental session at the engine test bench the TEG showed a very low performance (around 50% of the output power recorded during the first testing campaign), due to short-circuits between cartridges and external case, causing a dispersion of the generated current to ground and therefore it was replaced with a proprietary TEG (GEN4 - drawing n. TEG12-11595) supplied by Gentherm.
Electrification of components
An innovative multi-phase design of an electrical water pump and an electrical oil pump as 48V application was executed and then the 48V electronic approach was transferred to all other e-auxiliaries (e.g. alternator, e-hydraulic power steering, climate compressor, brake air compressor....); however the 48V electrification of the water-pump showed no energetic positive result, because the electrical production of energy as well as the
conversion to mechanical actuating power came along with electrical losses. Based on component behavior simulation it has been concluded that 48V is less cost efficient in comparison to 12V versions.
The simulation also showed that the electrification of the oil pump can be seen as a potential application for an
energy efficient powertrain solution, in fact over the ACEA cycle the energy balance of the electrified pump, under the condition of a lower pressure, is positive; nevertheless it was not implemented to give priority to the kinetic energy recuperation out of a belt driven starter generator, since the energy generated of the TEG and the Turbo-Generator is not even sufficient for the electrical base load (700W) for which reason an electrical generator is necessary.
Electrical Architecture with Storage System and PMU
Due to the need of energy harvesting and a high energy demand of the beltless engine concept a multi voltage architecture was set up which shows best performance to fulfill these requirements.
Taking into account the simulation results and the components specifications out of the consortium, to ensure the greatest possible flexibility and a high failure security a 48V and 24V main net and 12 V part net was set up inside the chosen E/E architecture.
Inside this concept the central regulation of the energy distribution takes over the Power Management Unit (PMU) which communicates via CAN-Bus with the electrical components.
The energy balance between the three nets (48V / 24V / 12V) was solved on the use of a 48V/24 DC/DC converter and a 48V/12 DC/DC converter. Therefore an efficient DC/DC converter was developed and implemented as multi stage approach to fulfil the need of the overall system.
An innovative e-storage concept was developed using a battery / DLC capacitor stack for 48 V board net level to deal with basic electric load coupled with the need of high energy peaks.
Then to ensure the failure security of 24V main net two 12 V AGM (Absorbent-Glass-Mat-Battery) are integrated, while to fulfill the requirement of energy harvesting out of recuperation during short time (fast energy storage) coming from the BSG a Double Layer Capacitor (DLC) was implemented into the E/E architecture; such a system gives the possibility to use the battery for storing the energy (e.g. provided by the E-generator or the TEG-generator) as base load and the DLC stack for high energy peaks (e.g. in case of drag moments of the e auxiliaries).
This e-storage system gives the options of transferring the energy in between the two storage systems according to overall system energy demand. In parallel, this approach is used for board net stabilization.
Subsystems control strategies development
Out of the overall E/E system design, the subsystem operation strategies for all e-components, including storage system of the beltless engine concept following typical heavy truck drive cycles demand were defined. Based on this operation strategy, a controller software was developed and implemented in E-system controller. A concept approval was done with a small test bench battery prototype, building up a dedicated E/E system test bench, to validate the subsystem control strategy.
Water Cooled Electric Supercharger and Turbo-generator
The COBRA C80 24V unit from CPT was chosen as the e-Booster, while the 48V Integrated Gas Energy Recovery System TIGERS from the same supplier was selected as turbo-generator.
Virtual power pack and system integration
Among the advanced innovative contents of the power pack, only the BSG is installed directly on the engine, replacing the normal production alternator.
The integration of the BSG had a deep impact on the engine auxiliaries driving belt system, requiring an accurate design of a brand new dedicated auxiliaries driving belt layout, pulley, double belt tensioner, for motor/alternator modes, and support on the crankcase.
A new Poly-V belt has been installed, while the standard production belt has been shortened.
In order to increase the efficiency and optimize the performance of the BSG, the latter has been connected to the low temperature coolant loop through dedicated water hoses.
Subsequently a complete packaging study was realized (CAD) to assess in detail the constraint and opportunities related to the integration of the GASTone power-pack at vehicle level.
Three other devices (TEG, TBG and e-Booster) are installed on the chassis; the virtual installation took into account all the constraints related not just to geometrical location, but also referred to the working condition of the vehicle equipped with the new concept engine.
The 3D model definition of the definitive subsystems themselves was the first step, than they all were integrated on the vehicle according to the following criteria:
- optimized engine behavior
- the optimization of the performance of the devices themselves
- Vehicle layout constraints;
- the device installation constraints given by the supplier/producer
- Regulation for CNG fuel systems.
The target was to fully implement the established schematic layout with the lowest possible impact on the normal production vehicle; the most modified subsystems of the n. p. vehicle were: the front radiator module, the air intake loop, the exhaust line and the fuel supply line.
A concept for the integration of the thermo-electric generator into the exhaust system, considering the optimal location of the TEG as well as the optimal performance of the exhaust system was developed, as well as a concept for the integration of the cold side heat exchanger of the TEG into a cooling system of the power pack. In order to maximize the available heat from the exhaust gas, the TEG integration on the new exhaust pipe line has entrained a major impact on the current vehicle layout; the TEG was installed as close as possible to the ATS outlet. According to specifications and once verified the best achievable performance with simulations, the TEG has been connected to the low temperature cooling loop. The fixing brackets were already available on the chassis, namely being those originally supporting the CNG tanks that needed to be moved away from that area in which both the TEG and TBG were installed; the TBG was installed directly downstream the TEG.
The TEG’s outlet goes directly to the TBG’s inlet port by a dedicated interface with a conical shape, creating a convergent pipe branch and causing a considerable increase of the pressure drop. The electric turbo generator (TBG) is a passenger-car derived component that was adapted to the current engine. The device is cooled down by connecting it to the high temperature cooling loop, according to CPT’s cooling specifications, parallel connected to the transmission oil cooler.
The e-booster (electric compressor) is a passenger-car derived component that was adapted to the current engine and is placed downstream the current air filter and upstream the turbocharger inlet in a separate air pipe to be by-passed when needed, by means of a dedicated by-pass valve that has been integrated in the standard production charge air pipe.
According to the supplier specifications, the integration required a new support bracket, connected to the vehicle chassis, that guarantees the correct impeller axle orientation and the suitable coolant connection positioning; the device is connected to the low temperature coolant loop.
This installation deeply modifies the charge air system layout: the blow-by and pop-off pipes have been moved before the e-Booster by-pass valve, in order to prevent the pressurized air from the e-Booster to go upstream these pipes routing, bringing about critical conditions for the engine performance. The installation of the device on the chassis allowed to decouple relative shaking between the engine and the component itself.
The n. p. cooling system is not designed to satisfy all the different requirements of the new users that, according to their specifications, need an optimized mass flow and working temperature range, that may be very different from those determined by the ICE operation: therefore a dedicated thermal management system with a new thermal module has been implemented; the new thermal module was designed taking into account the performance optimization activity carried out with dedicated simulations, and has been fully integrated in the virtual layout.
The low temperature (LT) cooling loop handles the heat rejection by the e-booster, TEG, BSG and WCAC (Water Charge Air Cooler); all the devices in the LT cooling loop have been connected in parallel with a dedicated brand new conveyor. The implementation of such a dedicated thermal system required the introduction of:
- A new LT radiator in the front module;
- A new dedicated coolant tank;
- Two dedicated conveyors;
- A 12 V electrical pump.
All the electronic devices dedicated to the electrical power management, storage and control (DC/DCs, dual layer capacitor – DLC - and control unit) were installed inside the longitudinal members of the chassis, in the rear of the vehicle, with no impact on the rear part of the chassis that would involve the reduction of the available cargo volume.
All clearance prescriptions have been complied with, according to internal design standards.
System physical integration and experimental validation
A 6 cylinders CNG engine was equipped with e-auxiliaries and mounted at test bench after metrological measurements for configuration sign off.
Afterwards new engine components were integrated together with control system to manage e-devices.
The Engine characterization in current production configuration in terms of performance, fuel consumption, emissions, heat rejection, friction and pumping losses and turbocharger performance (boost, flow rate) was performed.
After characterization of the baseline and engine updating with e-devices, the characterization and validation of the new adopted technical solution was performed as follows:
- Behavior measurement of e-water pump and calibration of related control management.
- Calibration of e-boost.
- Full comprehensive calibration of all e-devices.
Since a new thermoelectric generator type was introduced to replace the previous TEG setup, which was damaged due to short-circuits between cartridges and the external case, causing a dispersion of the generated current to ground, two different TEG prototypes were tested: the new TEG Gen4 demonstrated a better efficiency, even more without an external by-pass valve, which was necessary for operation of the first proto.
- Engine characterization with updated configuration in terms of performance, fuel consumption, emissions,
heat rejection, friction and pumping losses and turbocharger performance (boost, flow rate).
The measurements were done at fixed point representative of relevant engine speed/load of real mission and then a dynamic behavior was assessed at dynamic engine bench test according to WHTC and real life conditions (ACEA cycle).
The experimental validation was intended to assess the benefit of GASTone power pack in increasing vehicle/engine efficiency, during both steady-state condition and real life conditions (ACEA cycle).
The first validation testing activity was carried out with the aim to validate the e-Booster only.
The base engine, with the e-Booster installed in the air inlet line, was assessed on the ACEA reference driving cycle, in terms of inlet/outlet pressure upstream the current turbocharger and in terms of e-Booster power absorption, considering its impact on fuel consumption; some benefit on time to torque reduction has been verified, but with a negative effect on fuel consumption, due to electrical absorption.
The second validation testing activity was carried out with the aim of validating the TEG (Gen4 -2 modules in series) only. The Thermoelectric Generator (TEG) was preliminary assessed in terms of electrical power output on engine map and then the base engine, with the TEG installed in the exhaust line, was assessed during the ACEA reference driving cycle, in terms of backpressure increase and in terms of TEG energy production, considering its impact on fuel consumption: TEG effect on backpressure is limited, then negligible effect on fuel consumption is measured.
The third validation testing activity was carried out with the aim of validating the configuration with the TEG and the TBG. The base engine, with the TEG and TBG installed in the exhaust line, was assessed during the ACEA reference driving cycle, in terms of backpressure increase and in terms of electrical energy production, considering their impacts on fuel consumption: the addition of TBG causes an high backpressure increase that in its turn leads to a fuel consumption increase.
The fourth validation testing activity was carried out with the aim of validating the configuration with the BSG, with the presence of the TEG in the exhaust line. The base engine, with the BSG integrated on engine and the TEG installed in the exhaust line, was assessed during the ACEA reference driving cycle, in terms of BSG energy production and in terms of energy absorption, considering their impacts on fuel consumption also: when battery state of charge is > 50%, BSG can be used as motor and fuel consumption reduction is achieved.
Different strategies of energy recuperation were tested for the BSG, confirming that the most efficient one is to
have the BSG produce energy during deceleration periods (fuel cut-off) of the reference ACEA driving cycle, because of the friction increase during electrical energy production; the BSG efficiency was assessed to be around 60-70%, depending on the engine speed.
Benefit estimation at vehicle level and applicability study on diesel engine
An applicability study was carried out using the dynamic model of the engine and its energy balance.
The analysis considered at first only CNG engine while in a second phase the benefit and limit of a diesel GASTone power pack was also assessed.
The total electric production generated by the TEG, TBG and KERS was estimated: the KER in deceleration periods is the main producer while the TEG and the TBG contribute to the system approximately in the same percentage; the most important electric consumers are the pump of the high temperature cooling loop and the oil pump, followed by the accessories consumption, accounting in the whole for 90% of the total electric consumption.
The best combination apparently is the BSG system used as a producer as well. Nevertheless, the combination of the KERs system with the TEG and TBG results also very attractive being able to achieve a considerable fuel saving rate.
Each single device alone or even the combination of the TBG with the TEG do not generate enough electric energy to supply the auxiliaries, the same applying to the BSG in deceleration periods only.
In the investigated case, the average gas mass flow in the Diesel engine resulted to be double than in the CNG engine. Among the inquired technologies, the generation of electricity by the TBG is controlled by the mass flow as the dominant variable and therefore this latter technology is likely to be more adequate to Diesel engine applications.
In this case, the average temperature over the cycle by the CNG engine is 22% higher than by the Diesel engine, this latter being around 300ºC lower than by CNG engines. Therefore, recovery technologies which control factor is the temperature, as the TEG, show a greater potential in CNG engines.
Therefore, from the point of view of potential energy recuperation, the quality of the wasted thermal energy of the exhaust gas is lower in Diesel engines. The consumption share of the electrified auxiliaries remains very similar to the one observed in the CNG engine. Nevertheless, in this case the highest consumer is the electric oil pump, while the high temperature water pump requires less water mass flow through the cooling loop thanks to the lower combustion temperatures of the DIESEL engine, resulting in a lower consumption by this component.
The maximum fuel saving along the ACEA cycle is 18% lower for Diesel engines than for CNG engines for the GASTone proposed configuration.
In conclusion the most versatile technology used in the GASTone approach is the BSG system, able to produce electricity at any time ensuring the availability of the electricity even though it is not always for free.
The new generation TEG does not have a high temperature limitation as the old generation but its power production generate is lower result than expected at the beginning of the project but still very interesting for its application.
The TBG shows the highest potential for energy recuperation, however, it causes too much backpressure on the engine side. Therefore, only upon solution of this issue, this technology would definitely turn out to be one of the most promising and cost-effective.
Cost and investment estimation
The GASTone engine system was analyzed as well as its on-board integration so to split the costs per function and to estimate the overall cost, based on different market scenarios (1000 vehicles/year vs. 5000 vehicles/year); to this purpose a complete and detailed bill of material was defined of the GASTone system taking into account mechanical fitting, piping and wiring, besides the major components, adding also the normal production vehicle and engine interfaces.
Once defined the BoM, the costs of each item has been evaluated in terms of variable costs and investments.
Make or buy elements were classified in different categories: in the first case it was also necessary to evaluate the investment costs related to the dedicated workstations, required at the vehicle assembly line for the completion of semi-finished products delivered by suppliers.
The cost issue was considered both from user point of view and industrial point of view taking into account direct costs as well as indirect costs; the production, usage, maintenance and dismantling related cost were be also considered in the frame of the estimation of the total cost of ownership and the dismantling issue was also included. The TCO estimation represents the overall expenditure, including both fixed and variable costs, from the one-off purchase price of the vehicle, to the annual operational expenses, up to the reuse/recycle/landfilling of the dismantled vehicular components.
In the GASTone project, the TCO estimation has been carried out with the purpose to compare the current production heavy duty truck IVECO Stralis Natural Gas Euro VI to the same vehicle updated with all the new GASTone technologies, resulting that the purchase cost of GASTone concept vehicle would be significantly higher than a comparable heavy-duty NG Euro VI vehicle.
The annual maintenance and repair cost of the GASTone vehicle is estimated as slightly higher than current NG vehicle, due to the installation of new components that are not present in the current vehicle.
Fuel cost is consistently the highest driver of the TCO calculation and it is addressed by the adoption of the GASTone technologies. The simulation model developed by the Polytechnic of Valencia predicts a fuel reduction during the ACEA cycle and this fuel consumption reduction means a lower expense on annual fuel cost. The taxes, insurance, tolls referred to the GASTone vehicle are assumed equal to the current one, since it is uncertain if in the near future the legislation could reward the vehicle with a waste energy recuperation system. The payback time of the incremental cost strongly depends on the fuel consumption reduction in comparison to the reference vehicle and its annual mileage. The business case, based on a mileage of 120 000 km/year, shows a not favorable payback time.
System technology feasibility
The system technology feasibility of the GASTone system has been demonstrated taking into account all the impacts that the introduction in a series production vehicle reflects.
A risk assessment wasbe carried out to identify any potential issue that might become a barrier for the desired implementation of GASTone system and A SWOT analysis (strength, weakness, opportunities and threads) was carried out, aimed at identifying the internal and external key factors influential to the successful achievement of the project’s targets. The following risk drivers have been identified:
- Customer Expectation Risk:
o Subsystem/ Component Content.
o Customer Usage.
o Functional Objectives.
o Reliability/Quality Prediction.
- Technical Execution Risk:
o System Interaction.
o Design Practice.
o Core Documents Integrity.
o Validation Testing.
o Vehicle Diagnostic Capability.
- Program Risk:
o Supplier Sourcing.
o Program Timing.
The risk can be evaluated as:
- High, if the component is brand new or a first application.
- Medium, if the specific application can be handled according to already available experience.
- Low, if the component is a carry over or a consolidated and already known technology.
Based on the output of the risk analysis and the SWOT analysis a system validation plan and a Risk Mitigation Plan were be generated. This plan resume all the mitigation actions needed to properly handle and reduce the risk down to the lowest level possible, with the indication of the begin and the ending of the activity required.
According to the project’s purpose and limitations the consortium agreed to edit the mitigation plan only for the components and systems that were rated with an HIGH risk, this means that the plan have to be integrated and completed in case of industrialization of the system.
The object of the SWOT analysis (strength, weakness, opportunities and threads) aimed at outlining the strengths of the GASTONE efficient power-pack to be leveraged in view of a possible industrialization phase of the relevant technologies to ensure its successful introduction into series production.
Even more, the intrinsic weaknesses of the developed system are investigated in order to anticipate any unsolved issue or open point which might hamper the penetration of the GASTONE enhanced power pack in the market, because of a lack of economic sustainability or insufficient reliability or simply because of a low acceptance of its novelty by the final customers.
Threats arising because of a changing legislative and regulatory scenario, competition from alternative emerging or better established technologies which might hinder the extensive adoption of the GASTONE approach in massive production are also taken into consideration, with the purpose of contributing to remove every possible road block towards the achievement of the sale of more efficient and cleaner power trains.
The same applies to the competing environment represented by alternative transport modalities and different options in long distance freight transportation which might be gaining ground, based on economic and environmentally related reasons.
The SWOT analysis has been executed by means of several brain storming sessions held separately at both CRF and FPT with different discipline specialists on the basis of internal know how and experience, then the related outcomes have been integrated into a single matrix; in CRF the brainstorming sessions were leaded by an expert in innovation methodologies in the role of facilitator.
The system key properties were grouped in the following main categories for internal or external factors:
• System layout interactions & controls.
• Production & service.
• Novelty & maturity.
• Innovative technology introduction in current vehicle.
• Dismantling.
• Verification & validation concepts.
• Market.
• Legislation.
• Economics.
• Supplier chain.
In the end it was reckoned that the GASTone system has a great potential for environmental and economic sustainability increase of the long haulage freight transport, which could make it an attractive and
successful product on the marketplace.
Nevertheless its introduction into series production would require managing and overwhelming the issues originated by its relatively high complexity and the important costs required by the technical and technological efforts and the associated capital investments.
The competition from other freight transport modalities (waterborne and railway mostly) and the general macroeconomic scenario, together with the changing legislative framework, add to the uncertainty surrounding the success chances of the initiative, which pay back to the OEM still needs to be demonstrated.
Potential Impact:
The project GASTone has substantially achieved its expected results, having accomplished the design, development, prototypal construction and testing at the dynamic bench of an enhanced CNG power-pack for a long haulage heavy commercial vehicle.
The final testing has singled out some limitations in the operation of the overall GASTone system, which hampered the achievement of the efficiency gain originally expected, mostly due to an increased counter-pressure caused by the turbo-generator, entraining a higher fuel consumption (BSFC) over the ACEA driving cycle, which being a standard component available on the market couldn’t be conveniently sized to match the engine displacement and power. Nevertheless the feasibility of harvesting and storing free electrical energy by means of the waste heat recuperation approach was demonstrated and the design of a suitably dimensioned turbo-generator would be a straightforward engineering problem.
However the most promising configuration - in terms of fuel consumption reduction – proved to be without the turbo-generator and the e-booster, since any benefit in using the e-booster is a reduction in turbo lag effect and time to torque, at the expense of an even higher fuel consumption increase associated with an electrical energy absorption.
The thermo-electric generator offers good potentials for energy production with negligible effects on fuel consumption, thanks to low counter-pressure.
The best performing strategy for the kinetic recovery system (BSG) proved to be producing electrical energy during deceleration periods and when the battery state of charge is < 50%; when the battery state of charge is > 50%, the belt starter generator (BSG) can be used as motor granting a fuel consumption reduction, which is achieved during the first 1500 seconds of the ACEA cycle.
In the whole during the project several different technologies aimed at improving the long haulage truck efficiency could be developed and assessed and the holistic approach to the engine and powertrain energy management could be explored.
Simulation tools to support the development of the system management and control strategies and the evaluation of the adaptation of such a system to the various power trains were designed and implemented.
The different technologies aimed at the production of decarbonized energy, by the re-use of the waste energy, researched during the project will have a significant and positive impact on the long distance truck energy efficiency and CO2 emission reduction, irrespectively whether they will be applied either severally or integrated into a last generation CNG engine and in combination with electrified auxiliary systems to implement the beltless engine concept and to realize an highly efficient power pack.
In fact, despite Diesel engines having long been the most applied solution in the road transport sector for their high efficiency and power, and being expected to remain the dominant fuel for commercial vehicles beyond 2020, thanks to the availability of large worldwide reserves, natural gas benefits from more favorable and stable pricing, resulting in lower fuel costs and making it a truly viable alternative to Diesel.
Considering that the fuel burnt in a natural gas engine mainly consists of methane and that several countries in
Europe use bio-methane together with natural gas, and taking into account bio-methane life cycle emissions with its CO2 closed cycle, it’s clear that bio-methane proves to be a carbon neutral fuel.
The production potential for bio-methane is very significant, and would allow thousands of de-carbonized vehicles, fossil fuel-free driving resulting in a neutral carbon footprint.
Moreover synthetic gas is generated via gasification of surplus electricity (wind or solar), where renewable electricity is converted into hydrogen (through electrolysis) and then, by adding CO2, into synthetic methane.
As heavy-duty vehicles account for roughly 5% of Europe’s greenhouse gas emissions, assuming that 10% to 20% of the methane mix will come from renewable sources (bio-methane and power-to-gas) by 2030, when natural gas will account for over 26% of global energy demand, total reductions of up to 70% in CO2 emissions should be achievable compared to conventional vehicles, making methane the most cost-effective way to reduce CO2 from transport in the short to medium term.
The heavy-duty vehicle manufacturers contributed 550 billion € in gross value added (GVA) to the European economy in 2011; moreover, heavy-duty vehicles generated over 5 billion € trade surplus for the European Union in 2014.
In 2015, more than 350,000 heavy commercial vehicles were produced in the EU, and over the first three quarters of 2016 EU exports of light and heavy commercial vehicles summed up to around 7.6 billion €.
All the above statements give a precise dimension of the importance for the EU economy to keep its commercial vehicle sector highly competitive worldwide by the introduction of more efficient technical advanced products into the marketplace.
Rising manufacturing costs and greater utilization of rail networks (especially high-speed rail and inland waterborne transport ) are likely to exacerbate OEM competition even more in the future.
Therefore demand for low-cost trucks is expected to increase in medium- to long-term, fostering Turkey, India, Russia, and Indonesia as major low-cost manufacturing platforms.
Since the opportunities offered by the developed advanced technologies and their integration into a single system under a central control to implement optimized operation strategies are also pointed out as a possible unique selling product, comprising high added value and extending the OEM’s product range to compete on the global marketplace, the development of the concepts proposed in GASTOne provides many chances for the European industry to remain competitive and to gain market share in the area of technologies for energy efficiency in road vehicles. European vehicle manufacturers will be able to produce vehicles that meet exacting standards for energy efficiency whilst retaining the attributes of safety, comfort and performance that make European vehicles attractive to purchasers worldwide.
IVECO is predicted to take advantage of its China-based platform strategy, especially in South American and African markets, with China-made SAIC-IVECO trucks targeted to reach 65% of their total African sales.
While engine platform development is still focused on diesel engines, the rapid introduction of natural gas as heavy duty truck fuel (more than 8% penetration in new trucks by 2022) is boosting global natural gas engine development.
FPT developed a proprietary multi-point CNG engine for low consumption that meets Euro VI/EPA 10 and adopted a zeolite-based unique Selective Catalytic Reduction (SCR) technology to achieve Euro VI emission standards; without EGR, SCR or particulate filters, the latest generation Cursor 8 CNG Euro VI engine requires no additive and is 100% compatible with bio-methane. Thanks to its particularly efficient "stoichiometric" combustion, its pollutant emissions are much lower than those mandated by the Euro VI Directive as of 1st January 2014, with significantly less fine particulate matter and NO2 which are responsible for respiratory diseases in urban locations.
FPT, will exploit the outcomes of GASTone at first to strengthen its leadership in the domain of heavy duty CNG engines and then to improve the competiveness of the diesel engine range offering the opportunity to originate new innovative products.
Of all emissions standards, Euro VI had the greatest impact on vehicle design, as it required combining a high number of technologies in order to achieve near-zero levels of emissions.
IVECO overcame this challenge with a unique breaking through solution with no exhaust gas recirculation (EGR) for its whole range of trucks from 7.5 to 50 t Global Vehicle Weight.
Entrusting the entire anti-emission process to the HI-SCR system , IVECO escaped the trend for increasing complexity of diesel engines, while improving reliability and, ultimately bringing reductions in the Total Cost of Ownership (TCO).
Since the late 90s, IVECO has developed a wide range of engines, ranging in power from 136 hp to 330 hp, that run either on natural gas or bio-methane (in its renewable version), whether compressed to 200 bar (CNG) or in liquid form at -130°C (LNG). Twenty years of experience builds IVECO's status as leader in alternative natural gas-powered propulsion, with more than 24,000 engines produced.
Nowadays, since FPT acts as the major engine/powertrain components product development and supplying partner for IVECO trucks, the strong relationship of FPT with IVECO will allow to exploit the results in the domain of large truck and medium commercial vehicles with the overall goal to reduce CO2 emissions and fuel consumption and to increase vehicle fuel economy.
Furthermore, the concept of an integrated thermal system and the use of the thermal energy in rational way based on advanced components and sophisticated algorithms provides many global business opportunities for the European component supply industry thus further contributing to European competitiveness.
From the beginning of the project a website was made available and continuously updated throughout the project in order to diffuse basic information of the project (e.g. objectives, partners, publications...).
Moreover the project results were published in the automotive sector and scientific community along the whole project duration, disseminating them in the most relevant events of the automotive industry.
Following presentations were given:
“GASTone: New Powertrain Concept based on integration of Waste Energy Recovery, Storage and Re-use”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi, Daniela Magnetto
European Conference - Thermal Systems and Aerodynamic Solutions for Ground Vehicles – Trends and Challenges for New Levels of Comfort and Energy Efficiency ATA – Associazione Tecnica dell’Automobile, Torino June 17th – 19th 2015.
“Development of a new powertrain concept based on the integration of electric generation, energy recovery and storage”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi, Daniela Magnetto
“Model of a new powertrain concept based on the integration of electric generation, energy recovery and storage”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Corberán Salvador, Alex Rinaldi, Daniela Magnetto
International Conference and Exhibition on Automobile Engineering, Valencia September 1st – 3rd 2015
“GASTone: Nuova concezione di propulsione basata sull’integrazione dei sistemi di recupero e riutilizzo dell’energia”
E. HERVÁS-BLASCO, E. NAVARRO-PERIS, J.M. CORBERÁN, D. MAGNETTO, A. RINALDI
Giornata di Studio Tecnologia Termoelettrica per il Recupero di Calore Disperso - Fondamenti e Applicazioni, Milan October 8th 2015
“Dynamic Model of a New Powertrain Concept Based On Energy Recovery from Exhaust Gases and Kinetic Losses to Electrify the Main Auxiliaries Oriented To Reduce Fuel Consumption”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi
“ GASTONE: New Powertrain Concept for CNG Engines”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador, Alex Rinaldi
SAE World Congress & Exhibition, Detroit (MI) April 12th – 14th 2016
“GASTONE – Development of a New Powertrain Concept Based on the Integration of Electric Generation, Energy Recovery and Storage Efficiency”
Alex Rinaldi, Alberto Maria Merlo, Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador
6th Transport Research Arena Warsaw, April 18th - 21st 2016.
“Optimal configuration of a thermoelectric generator to recover wasted heat”
Estefanía Hervás-Blasco, Emilio Navarro-Peris, José Miguel Coberán Salvador
VIII Congresso Ibérico – VI Congresso Ibero-Americano – Ciencias E TECNICAS DO FRIO
May 3rd – 6th 2016 Coimbra, Portugal.
“Gastone: an integral approach to maximize efficiency in heavy duty CNG engines”
Alberto Maria MERLO, José M. CORBERAN, Stefano GOLINI, Shaun MCBRIDE, Roland ÖLLER, Andreas SCHIESSL
CO2 reduction for Transportation Systems ATA - SAE Conference in Turin on June 29th - July 1st 2016.
“GASTone: an integral approach to maximize efficiency in heavy duty CNG engines”
Alberto M. Merlo, Alex Rinaldi, Stefano Golini, Francesco Tucci, Rainer Gietl, Andreas Schiessl, Estefania Hervas Blasco, Emilio Navarro Peris
EGVIA workshop on Heavy-Duty Vehicles held in Brussels on May 31st 2017.
In the whole the project has been presented in 9 International Conferences with a total of 12 contributions in 6 different countries, including the United States of America.
A special session dedicated to the GASTone project was organized within the International “Congress on Transport Infrastructure and Systems (TIS)” held in Rome by the Italian Association for Traffic and Transport Engineering in the headquarters of the “Automobile Club d’Italia”, on the 12th of April 2017.
Eleven presentations were given, reflecting the work-package brake-down structure and summarizing the most meaningful results of the project.
Besides the training of young engineers and scientists, and in the dissemination of the project in the academic sector
Two workshop sessions addressed to the students in the UPVLC were given on April 28th and May 12th 2016:
1. Next technologies to increase the efficiency of heavy duty vehicles. Un ejemplo de ingeniería integral
Speakers: Estefanía HERVAS-BLASCO, Emilio NAVARRO-PERIS, José M. CORBERÁN
Conference given at the UPV as a training for new engineers and scientists form the mechanical, electronic, electric, automatic engineers on April 28th 2016.
2. Next technologies to incresase the efficiency of heavy duty vehicles. An example of integral engineering
Speaker: José M. CORBERÁN
Conference given at the UPV as a training for new engineers and scientists form the Energy, Chemical, industrial organization and industrial engineers on May 12th 2016.
An introduction of the main objectives and achievements of the project GASTone was given on March 28th 2017 to FCA Product Development engineers during the professional training “Corso PD Architetture elettriche modulo 1 - i veicoli ibridi” (Electric Architectures module 1 – Hybrid Vehicles).
Gentherm presented a stand at the IAA Commercial Vehicles 2016 exhibition in Hanover (Germany) on the 22nd- 29th of September in 2016.
A screen with the project presentation was placed in the stand, thus disseminating the existence of the GASTone project within a commercial automotive sector.
The exploitation plan for the commercial exploitation of the scientific and technical results was developed.
As automotive research and innovation center, CRF works on different technologies in order to jointly achieve the fuel economy targets and environmental sustainability goals, consistently with the standards in force and by the expectations of the wider society, which are the R&D major drivers in current product development, in the field of passenger cars.
In particular waste heat recovery is one of the topic in which CRF is investing its efforts and the thermo-electric generation is one of the technologies investigated.
Therefore CRF aims at consolidating its knowledge on thermal and kinetic energy recovery systems in order to foster the development and design of a series of devices to be installed on different applications, accordingly with the company mission of its parent company FCA to widely implement these technologies in passengers cars.
Moreover the GASTONE project is interesting for CRF, having allowed to investigate several other implemented technologies such as the 48V electrical architecture and the electrification of different auxiliaries, in particular the electrical coolant pump for the dual level cooling system and in replacement of the mechanical engine coolant pump.
The higher power level of these auxiliaries means a higher specific performance and efficiency, staying in a voltage range not requiring any galvanic insulation of the specific electric board-net, which would be needed for voltages higher than 60V.
Engineering Center Steyr GmbH & Co KG (ECS) is a world leading engineering service provider for development and engineering, in the following areas:
- Commercial vehicles
- Powertrain systems
- Non-road-mobility
- Alternative mobility and transportation
- Thermal management
- Railway systems
- Fluid and pressure technologies
- Sports cars
- Leisure and marine vehicles
- Technology & software
- And system integration.
The main interest of ECS regarding the GASTone program is to become an engineering partner providing a complete service of TEG system and components integration from concept to series application, by the integration of TE modules to get a complete TEG system.
Opportunities for using the gained knowledge during the program will be:
- Development of simulation models for optimal TEG system sizing
- Integration of TE modules available on the market
- Application of TEG systems on gas powered commercial vehicles:
- Testing of TEG systems on engine test bed and on complete vehicles:
- Development of DC/DC converter for high current and low voltage area.
- Development of a TEG control unit as MPPT (maximum power point tracker) including control of bypass systems to provide an intelligent TEG system component.
- Development of an overall TEG system operating strategy.
Due to a strategic shift in the scope of MAGNA as parent company, ECS is focusing more on passenger cars than on commercial vehicles in the future.
GENTHERM designs, develops and markets innovative thermal management technologies based on advanced, proprietary, efficient thermoelectric device technologies for a broad range of global markets and heating and cooling and temperature control applications.
GENTHERM’s advanced technology team is developing more efficient thermoelectric materials and systems for waste heat recovery and electrical power generation for automotive, industrial and other markets.
With approaching global requirements for vehicle carbon emissions and calls for cleaner vehicles, the Thermoelectric Generator (TEG) is at the technological forefront as a solution for meeting changing market demands.
Focusing on the development of advanced, high temperature, scalable thermoelectric modules, GENTHERM are driven to cement their position as the world’s leading supplier of high performance integrated thermoelectric modules for power generation. The benefit of the proprietary knowledge and know-how developed during the GASTone project is twofold, in that it helps to further GENTHERMs’ opportunities to develop and engage in the heavy duty market, while also analyzing the potential for thermoelectric power generation in CNG applications.
The knowledge gained will be used in future projects examining heavy duty applications as well as passenger vehicle and light commercial vehicle applications to provide further optimized and improved technical and economical solutions.
Since IVECO (CNH Industrial group) is very well positioned in LNG/CNG market, in all vehicle segments, the market entry is a very crucial point and has to be correctly exploited to reach the maximum impact and to possibly increase the actual sale volumes of long haul truck.
FPTI plan for the exploitation of the GASTone project results is a roadmap towards full implementation of the concept within 2020, bringing the technologies through to series production after having completed the industrialization of new systems in the Cursor Natural gas engines: the main marketing message would be
- The availability of an innovative product for the existing market of fleet operators
- The confirmation of the advanced energy recovery approach combined with a reduced fuel consumption, focusing on the reuse of the waste heat of exhaust gas and the partial kinetic energy recovery
Main goals to be reached and communicated would be:
- Engine improved performances
- Turbo-lag reduction (with e-booster implementation)
- Fuel saving (thanks to BSG contribution as a motor).
With its innovative products, Continental helps vehicle manufacturers to meet regulatory requirements, which are stricter in the field of commercial vehicles than anywhere else. That`s how the company is paving the way for tax benefits or reductions in road use fees for especially clean vehicles.
When developing components for commercial vehicle drive systems, Continental focuses on profitability for fleet operations and offers various solution strategies and existing technologies around the world, in order to fulfill the goals of the markets as needed.
The propulsion and energy system investigated within the GASTone project plays an important role to clarify how far electrification and energy recovery will penetrate the commercial vehicle market. Potential savings in fuel consumption and subsequent CO2 emissions are known to be strongly dependent on system efficiency and energy losses within the primary and secondary propulsion and powertrain components. In particular, the energy management and board net (based on 12V/24V/48V multi-level voltage) has been proven to be crucial for efficient energy generation, distribution and partitioning of the whole system. Therefore, Continental is developing a specially tailored power management unit to monitor, control and distribute electrical power flows within the complex E/E architecture.
In addition the electrification of the oil-pump is seen as benefitting CO2 reduction at system level. That´s why Continental is considering to start developing such an auxiliary for commercial vehicle application.
The development of this multi voltage E/E architecture will allow to implement in a next step newly developed even bigger auxiliaries with significant participation of electric power consumption (>1kW peak), e.g. AC-compressors, e-Booster or bigger liquid pumps.
One key role for fulfilling the need of CO2 reduction within the new developed multi voltage approach in GASTone is played by a belt starter generator, which will act as major contributor on the energy generation side. Peak performance of more than 12kW can be handled efficiently only within a 48V stage, in combination with DLC (double layer capacitor) and rapidly controlled DC/DC converter. Therefore these components are in focus for future developments and potential products that could be provided by Continental to commercial vehicle OEMs.
Control strategies as well as energy generation, consumption, storage and distribution of electrical power have been developed and advanced during Continental´s contribution to this project and will be further in future. Results and performance potentials will enter future product developments and facilitate functional assessment of emission-optimized powertrain systems. Such systems will furthermore enter the multi-voltage as well as the single-voltage board stages for commercial and passenger vehicles under consideration of the GASTone project results and the current research of the consortium partners.
List of Websites:
http://gastone-project.webs.upv.es/
Alberto M. Merlo
Senior Specialist Public Funding
Interiors Systems Department
Vehicle Research & Technologies
C.R.F. S.C.p.A.
Corso Luigi Settembrini, 40
10135 Torino, Italy
Tel. +39 011 00 42 7 24
ALBERTOMARIA.MERLO@CRF.IT
Sede legale e amministrativa, Strada Torino 50
10043 Orbassano (TO), Italia