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Gas-Only internal combustion engines

Periodic Reporting for period 3 - GasOn (Gas-Only internal combustion engines)

Periodo di rendicontazione: 2018-05-01 al 2019-04-30

Sustainable mobility in Europe for more efficient road transport by 2020+ can be achieved improving vehicle aerodynamics, weight reduction and influencing driving patterns but also a considerable contribution is expected by powertrain efficiency improvement.
The use of Low Carbon Alternative Fuels, such as Renewable Natural Gas, plays a fundamental role to accelerate the process of decarbonisation of the transportation sector that in Europe is targeted for 2050. Natural Gas / Methane has the potential to play a major role as automotive transportation fuel of the future passenger cars, trucks & buses, being environmentally friendly energy carrier easily produced by different renewable pathways. Furthermore, the fuel characteristics of methane allow to achieve significantly increased engine efficiency by means of optimized dedicated CNG-only.
A 100 % CO2 free mobility is also possible with CNG vehicles by a simple replacement of fossil CNG by renewable types of methane (e.g. e-methane or bio-methane). Since all of these fuels are fully miscible, the replacement can occur in a smooth transition, without the limitation of blend limits (as e.g. occurring for ethanol in fossil gasoline or bio diesel in fossil diesel).

Conclusion of action
The development of advanced technologies dedicated for CNG-only engines was successfully completed as scheduled. The call action was executed demonstrating a reduction of 20% of Green House Gases (vs 2014-2015 best in class CNG vehicles) by means of vehicle demonstrators tested by JRC in Real Driving tests. All the gaps (performance and driving range) were removed versus conventional propulsions. The developed technologies are fully compatible with renewable methane and show lower total cost of ownership compared with conventional and electrified propulsions.
The following results are achieved:
• Stoichiometric & high structural integrity small TC VVA CNG DI engine: direct injectors prototypes have been realized and installed on the 3-cylinder CNG engine; the engine was fully characterized and calibrated at test bench with excellent results (gasoline-like performance). Finally, a demo vehicle equipped with the new engine and the new storage system was able to comply with ~600km driving range on NEDC/WLTC. JRC witness tests confirmed the capability to reduce 20% CO2 emissions vs best in class B-segment vehicle on WLTC and drastically reducing PN23nm & PN10nm emissions on RDE (30 times less than Euro6d final limit) and simultaneously complying with Euro 6d limits.
• Super downsized CNG engine with advanced boosting and VCR: in order to demonstrate 20% CO2 emissions reduction (NEDC) vs. the best-in-class CNG vehicles 2014, EU6+ emission capability and 600 km mileage range, a new developed 1.0l-3-cylinder dedicated CNG engine was developed, installed in a prototype vehicle and fully calibrated. All new engine subsystems were designed for high pressure CNG combustion conditions. Robustness was validated and largely confirmed for all new components. The maximum power and torque objectives were achieved. 6 CNG tanks were installed on the prototype vehicle to ensure the targeted 600 km range. Finally, JRC witness tests confirmed the capability to reduce 20% CO2 emissions on NEDC and drastically reducing PN emissions (30 times less than Euro6d final limit) in NEDC, WLTC and RDE and simultaneously complying with Euro 6d limits.
• Charge dilution & exhaust gas temperature management was applied by means of VVT coupled to VVL and Low Pressure cooled EGR to extend stoichiometric operation and reducing fuel consumption at part load. Efficiency-improving technologies were introduced to reduce CO2, like high compression pistons, variable valve timing, 2 step variable lift, variable nozzle turbocharger and low pressure EGR. The results confirmed 20% CO2 gain compared to best in class CNG van as reference.
• Non-DI CNG lean burn combustion process: the focus is to develop an active pre-chamber concept fuelled by CNG. The best designed pre-chamber geometry allows engine operation between lambda = 1.4 – 1.7 in this area prototype engine reached brake engine efficiency up to 45% vs today best value of 38% with still low NOx values while a stable engine running and stable ignition are guaranteed.
• On-board gas quality CNG sensor: two concept were developed thermal-base and optical base. The optical sensor resulted the solution for further development and series production. This sensor will help to increase the engine efficiency of all CNG light duty vehicles, through the possibility to set ignition timing for all gas qualities to maximum efficiency and enable a predictive engine control parameters optimisation.
Dissemination: 60 actions were carried out along the project timeframe.
Exploitation: GasOn Consortium is interested to make a big step with this project to the market introduction of best gas-only CNG passenger cars and foreseen a considerable share of gas-only vehicles within the next years. The aim to develop new CNG technologies will help to increase the acceptance of gas vehicles by considerable efficiency, significantly decreased CO2 and reduced real driving emissions. Pre-series and series development will follow the GasOn project.
The GasOn project technologies & results (increased range, gasoline-like performance, EU6+ emission compliance and lower fuel consumption) can lead to further market penetration of clean vehicles attracting new customers supported by appropriate incentives and sufficient CNG station infrastructures.
After a basic simulation (e.g. up to 4% market share) the CNG market can then grow on itself. Moreover CNG can simply be replaced with sustainable fuel of the highest available land use and CO2 avoidance efficiency, as bio-methane and PtG (power-to-gas) methane (made by renewable hydrogen and CO2 captured from the environment). This is the basis for a 100% sustainable mobility.
The applicability of GasOn technologies to CNG products for European market as well as to abroad markets will strengthen the competitiveness and growth of European companies, which own the technology significantly. Europe can come out as the leading driver for automotive CNG/methane technologies.
Therefore a new deal has to be considered for energy and fuels for transportation sector. The greenhouse gas reduction effect of renewable types of methane is not considered by the European legislation, because vehicles are accounted based on their TtW (Tank to Wheel) CO2 emissions, while the legislation for fuel production process misses to account the CO2 emissions emitted during the combustion of a fuel.
It is recommended to account the CO2 emission caused by burning the fuel, as well as their compensation by sustainable e-fuel production, as “Life Cycle WtT-CO2 target” in the RED II+, which consist of 3 CO2 parts (g/MJ): emitted during fuel production/transportation, emitted by burning the fuel and captured during production process of renewable types of methane.
With such a regulation, renewable types of methane production can be triggered. Finally, at 100 % renewable types of methane use, the tailpipe CO2 of a CNG vehicle would not be harmful anymore, since a fully closed CO2 cycle had been established. In that case vehicle CO2 targets are becoming obsolete and it can be considered to replace them by efficiency class targets (A, B C,...) as already established for vehicles in the EU.
On board gas quality sensor
Demo car PN measurements
Super downsized CNG engine with advanced boosting and VCR
Charge dilution and exhaust gas temperature management
Non-DI CNG lean burn combustion engine
Life cycle CO2 emissions
Stoichiometric & high structural integrity small TC VVA DI engine