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Executive Summary:
In the year 2004, the Integrated Project HERCULES-A (High Efficiency Engine R&D on
Combustion with Ultra Low Emissions for Ships) was initiated by the major engine makers MAN & Wärtsilä, which together hold 90% of the world market. It was the Phase I of the HERCULES R&D programme on large engine technologies (Figure 1). HERCULES-A involved 42 industrial & university partners, with a budget of 33M€, partly funded by the European Union. The project was broad in the coverage of the various R&D topics and considered a range of options and technologies in improving efficiency and reducing emissions.
HERCULES-B was the Phase II of the Programme, from 2008 to 2011, with 32 participant organisations and 26 M€ budget, partly funded by European Union. The general targets for emissions and fuel consumption were retained in HERCULES-B. However, based on the developed know-how and results of HERCULES-A, it was possible to narrow down the search area, to focus on potential breakthrough research and to further develop the most promising techniques for lower specific fuel consumption (and CO2 emissions) and ultra-low gaseous and particulate emissions.
The HERCULES-C project (2012-2015) was the Phase III of the HERCULES programme and adopted a combinatory approach, with an extensive integration of the multitude of new technologies identified in Phase I and Phase II, for engine thermal processes optimization, system integration, as well as engine reliability and lifetime (Figure 2). The HERCULES-C was supported by the European Union within FP7, with 22 participant organizations and 17 M€ budget. The Consortium included engine makers, component suppliers and equipment manufacturers, compounded by renowned universities and research institutions. The HERCULES-C was a large scale project, integrating technologies in ALL the significant areas of marine diesel engine development (Figure 3). The integrated RTD work in the Project included analysis, simulations, design, development and prototype testing, as well as selected full scale testing. The Project structure of work comprised 10 RTD Work Packages, as well as 3 managerial Work Packages (Figure 4).
- The First Objective of HERCULES-C was to further reduce fuel consumption of marine engines by 3% (over the Best Available Technology 2010) and thus reduce the CO2 emissions further. Achieved within the project was 1% from Low temperature Combustion (WP1), 1% from DF-engine optimizations (WP1), 2% from Combustion optimization (WP2) and 1.5% from Intelligent engine / Advanced plant control (WP7) as well as from Pressure based cylinder-individual control, health monitoring technologies (WP8).
- The Second concurrent Objective was to reduce marine diesel engine exhaust emissions by 80% over the IMO Tier I limits, towards near-zero levels. To achieve the emissions objective, the best technologies developed in the preceding projects I.P. HERCULES (A) and HERCULES-B were combined and integrated. Achieved within the project was 50% reduction for Particulate Matter (PM), 50% reduction for Total Hydrocarbon (THC) and 80% for NOx, through contributions from DF-engine optimizations (WP1), EGR - Gas operation on EVE (WP1), Combustion optimization / multi-fuel (WP2), Aftertreatment (DPF, EGR) (WP6) and Charging (VGT) (WP6).
- The Third Objective was to retain the marine engine powerplant performance at the almost “As-New” level, allowing only 5% divergence over the lifetime (20 years) of the plant. To achieve the objective of maintaining the as – new engine performance, developments in sensors, condition assessment and adaptive control methods were used, in conjunction with materials tribology and lubrication improvements. This objective can only be assessed a priori in a qualitative way. Thus, important contributions were achieved in new turbocharger technologies (WP1), Sensors, Monitoring, Adaptive Control (WP7) and more modest contribution from Tribology improvements (WP9) and (WP10).
The Hercules-C project objectives, targets and achievements are listed in Figure 5.

Project Context and Objectives:
HERCULES was conceived in 2002 as a long-term R&D Programme (Figure 1), to develop new technologies for marine engines:
• To increase engine efficiency, thus reduce fuel consumption and CO2 emissions.
• To reduce gaseous & particulate emissions.
• To increase engine reliability.
The R&D Programme HERCULES is the outcome of a joint vision by the two major European engine manufacturer Groups MAN & WARTSILA, which together hold 90% of the world’s marine engine market. It was the first time that these two Groups participated together in a project with commonly defined Research Areas.
Phase I of the Programme HERCULES materialized as the FP6 Integrated Project “I.P. HERCULES” jointly funded by the E.C. and Swiss Government. The I.P. HERCULES (A) Consortium had 42 partners (participant organisations) with a total budget of 33M€.
The I.P. HERCULES (A) was broad in the coverage of the various R&D topics and considered a range of options and technologies in each Work Package. Several cutting-edge test arrangements were designed and manufactured. Some highlights of achievements are shown below:
HERCULES- B was the Phase II of the original Programme concept. The project HERCULES-B run from 2008 for 3 years with 32 partners and 26 M€ budget. The general targets for emissions and fuel consumption were retained in HERCULES-B. However, based on the developed know-how and results of I.P. HERCULES (A), it was possible to narrow down the search area, to focus on potential breakthrough research and to further develop the most promising techniques for reduction in specific fuel consumption (and CO2 emissions) and Ultra-low gaseous and particulate emissions.
The technological themes of the HERCULES initiative have, since its inception in 2002, been higher efficiency, reduced emissions, and increased reliability for marine engines. However, for taking marine engine technology a step further towards improved sustainability in energy production and total energy economy, an extensive integration of the multitude of new technologies identified in Phase I and Phase II is required.
The HERCULES-C project was the Phase III of the HERCULES programme and addressed this challenge by adopting a combinatory approach for engine thermal processes optimization, system integration, as well as engine reliability and lifetime (Figure 2). In this way, HERCULES-C aimed for marine engines that are able to produce cost-effectively, the required power for the propulsion of ships throughout their lifecycle, with responsible use of natural resources, and respect for the environment.
The first objective of HERCULES-C was to achieve further substantial reductions in fuel consumption, while optimizing power production and usage. This was achieved through advanced engine developments in combustion and fuel injection, as well as through the optimization of ship energy management, and engine technologies supporting transport mission management.
A second specific objective of HERCULES-C is to achieve near-zero emissions by integrating the various technologies developed from the previous collaborative research efforts.
Furthermore, green product lifecycle technologies were introduced and the third objective was to maintain the technical performance of engines throughout their operational lifetime. This included advanced materials and tribology developments to improve safety and reliability, as well as sensors, monitoring and measurement technologies to improve the controllability and availability of marine power plants.
The HERCULES-C was a large scale project, integrating technologies in ALL the significant areas of marine diesel engine development (Figure 3). The Project structure of work comprised 10 RTD Work Packages, as well as 3 managerial Work Packages (Figure 4). Besides the above general objectives, specific measurable/verifiable objectives were set, related to each Work Package, to serve as Indicators of accomplishment. These objectives are outlined below, with respect to each Work Package.

Objective of Work Package 1 (“Advanced Combustion”) was first to evaluate a direct injection gas combustion system concept allowing improved emissions, and eventually efficiency, compared to current state-of-art gas engines. The second objective was to make improvements of multi-fuel engines efficiency and fuel switching technologies beyond current state-of-art, i.e. going for efficiencies η >47%. The third objective was to investigate partially pre-mixed combustion concepts with advanced fuel injection and air management systems included for control of the combustion process in order to reach IMO Tier 3 NOx as well as decrease in also other emissions mainly at part loads. The last objective was to make optimization of cool combustion systems for extreme Miller cycles in combination with exhaust gas re-circulation (EGR) to support the targets of Work Package 5.

The objective of Work Package 2 (“Computer Aided Combustion Optimization”) for both two- and four-stroke engines was to develop an optimized combustion layout and overall engine process to fulfill future emission standards. This aim was reached by using and developing innovative numerical models and optimization algorithms, which include both process calculation tools and CFD models. The effort in this Work Package was to clearly formalize the optimization scenarios of interest, find appropriate optimization strategies, interface with available software portfolio and automate the entire workflow. A significant part was also performed on model development, to be adaptable to upcoming optimization requests, as well as to preparing existing models for general purpose optimization routines. Subsequently, the optimal designs were evaluated and validated against engine tests to ensure that the design tool was trustworthy.

The overall objectives of Work Package 3 ("Injection, Spray Formation and Combustion") can be summarized as follows:
• CFD investigations of the flow inside the fuel injector and the impact of design and operational details.
• Experimental studies of the subsequent spray and fuel/air mixing processes at typical operating conditions.
• Characterization of the combustion process and its dependence on the injection, spray and fuel (in particular LFO vs. HFO).
• Further development, validation and application of CFD-based tools, techniques, and methods.

The objectives of Work Package 4 (“Experimental and Modelling Studies of Fuel Injection Systems”) were:
• To develop and apply both experimental and computational techniques to the study of fuel injection systems for large engines.
• To develop advanced laser optical methods for characterizing in-nozzle flow together with the near-nozzle spray flow field. Furthermore, this gained knowledge was used to enable visualization of sprays inside the T50ME-X test engine.
• To develop CFD tools for describing the fuel injection system. One tool developed predicted the discharge coefficient for individual atomizer nozzle holes. The CFD models were also developed such that they are applicable for optimization of other components in the fuel injection system.

Objectives of Work Package 5 (“Integrated Emission Control Technologies”) were first to investigate options for further optimization, integration and flexibility of key components of advanced turbocharging and emission control technologies. Second objective was to develop and test prototype(s) of integrated advanced turbocharging and emission reduction systems for IMO Tier III NOx emissions and best efficiency. Third objective was to develop a sequential aftertreatment concept which enables SCR operation on high sulphur fuel and makes SCR integration with scrubber feasible allowing near zero emission level (>90% reduction in NOx and SOx emissions). The fourth objective was to develop a scrubber concept capable of particulate reduction, up to70% with specific focus on pre-treatment based on novel electrostatic precipitator.

The objectives of Work Package 6 (“Near Zero Emission Combustion and DPF Technologies”) were as follows:
• To provide advanced turbocharging systems including exhaust gas recirculation (EGR) for low- and medium-speed Diesel engines to achieve International Maritime Organisation (IMO) Tier-III nitrogen oxide (NOx) limits.
• Modelling of turbocharger compressor surge and investigation on a medium-speed Diesel engine to achieve enhanced turbocharger operational stability.
• Achieve particulate matter (PM) reduction on medium speed Diesel engines by sequential Diesel particulate filter (DPF) after-treatment to United States Environmental Protection Agency (US-EPA) Tier-4 equivalent 0.04 g/kWh limits and adaptation and integration of advanced DPF technologies with optimal regeneration strategy for higher fuel efficiency.
• Develop a method and control strategy for mixing water and fuel just in time (JiT-WiF) before injection and combining it with EGR to achieve minimal NOx emissions at minimal efficiency and combustion deterioration.

The overall objectives of the Work Package 7 (“Advanced System and Plant Control”) were:
• Development of integrated computer-based optimization methods and systems to improve the total control quality of ship propulsions systems
• Development of model-based diagnostic and health monitoring methods to increase system availability.
• Development of adaptive and advanced control applications for extreme operating conditions to eliminate the need for manual tuning.
• New concept for thermal process adaption and control of total energy production, usage and storage.
• New concepts for ship propulsion supporting vessel asset management system and data management infra-structure.

The Work Package 8 (“Intelligent Engine”) was concentrated in the development of techniques for optimization of engine performance though implementation of control strategies and health & performance monitoring technologies. Three main areas of work were addressed to reach these goals. One the one hand, a system for controlling the engine was to be developed and validated based on a cylinder-individual pressure-based control scheme (ACC – Adaptive Combustion Control), thereby assuring that the engine is always running in an optimal condition with regards to consumption and emissions. On the other hand, sensor based health monitoring approaches were to be explored in order to be able to better assess the condition of the engine. A sensor for wear detection was to be developed and tested on an engine. Lastly, algorithms for the prediction of engine performance based on thermodynamic modelling were to be developed. These would allow a check of the engine condition through comparison of simulated with measured data and would also give indications for faulty behaviour.

The main objective of Work Package 9 (“Cylinder Lubrication Concept for Optimized Emissions”) was the development of an emission optimized lubrication concept. Dedicated measurement technologies were utilized to address a clear determination of lube oil losses and contribution to exhaust emission. Elaborated results targeted to clearly demonstrate a correlation between lubrication system parameter variations and the exhaust gas composition. Another objective in this context was t the development of a new cylinder lubrication concept incorporating the application of substantially modified engine components related to the lubrication system. The new approach in lubricating the cylinder liner – piston ring interface yielded a reduction of lubrication losses by 30% as well as the application of a lube oil property monitoring system to determine system parameter settings on basis of operational requirements.
The objectives of Work Package 10 (“Advanced Bearing and Combustion Chamber Technology“) are listed below:
• Reduce the piston ring wear by 10% and reduce piston ring-cylinder liner friction by 10% (2-stroke) and 20% (4-stroke).
• Identify new piston ring - cylinder liner materials and surface technologies suitable for large marine diesel engines.
• Development of low friction piston skirt with 20% lower frictional loss.
• Optimize main bearing design for increased reliability by the use of advanced optimization, fluid-structure, thermal modelling tools and in ‘engine-like’ test rig validation.
• Lower the frictional loss in the main bearings of two-stroke engines by 10-15%.
• Investigate the possibilities to reduce heat loss from combustion chamber components.

Project Results:
In order to achieve the general objectives of the Project, as well the individual objectives of each Work Package, as described in the previous chapter, upon completion of the Hercules-C project many important scientific and technological results were obtained. These are described in the paragraphs that follow, with respect to each related Work Package.

Outline of work performed in WP1: Advanced Combustion
Direct injection gas combustion system calculation studies were performed at Aalto University for optimizing injector type and geometry, piston geometry, injection timing and pressure. In Wärtsilä Switzerland the studies focused on comparison of gas admission concepts regarding mixture quality. After the theoretical studies, designs and rig tests were done, followed by real engine tests on the 2-stroke uni-flow scavenged RT-flex50D and 4-stroke 6L34SG test platforms in Trieste and Vaasa Laboratories respectively. Multi-fuel engine efficiency optimization tests were done on the Vaasa Laboratory test platforms W6L34DF and W9L20DF. Options investigated included testing of a turbine without lacing wire, part-load optimized turbo charger setup, use of a by-pass valve, as well as use of an optimized piston top and combustion setup. Partially pre-mixed and cool combustion concept evaluations started with simulation studies to optimize the fuel injection timing, nozzle hole size, spray angle, fuel injection pressure and piston top shape for the new concept to work optimally. After the studies, partially pre-mixed combustion experimental investigations were started on 4-stroke gas engines utilising the Vaasa Laboratory engines W6L20DF and W6L34SG as test platforms. Cool combustion tests on diesel engines together with an EGR system were performed at Aalto University where an EGR system was planned and built on the single-cylinder EVE engine. Cool combustion tests on 2-stroke engines were focused on designing and utilising a high pressure water injection system on the RTX-5 test engine in Trieste, Italy.

WP1 Achievements and Final Results
Low-temperature combustion tests done on both lean-burn gas engines (SG) and Dual Fuel (DF) gas engines resulted in improved engine efficiencies of about 0.5%-units and lower Total Hydrocarbon (THC) emissions. Cool combustion tests on the single-cylinder EVE engine at Aalto University including an Exhaust Gas Recirculation (EGR) system (visualised in Figure 6) and strong Miller cycle proved that the IMO Tier 3 NOx level is within reach also for diesel engines. CIMAC paper #288 in the CIMAC Shanghai Congress 2013 was written as an outcome of the cool combustion simulations performed. Objectives of the multi-fuel engine optimization tests were fulfilled with at the most 0.54%-units better engine efficiency. A part load optimized turbocharger (TC) setup was also proven to improve part load smoke emissions and fuel consumption due to the increased turbine efficiency achieved as seen in Figure 7. Use of control valves, an optimized fuel injection system setup, as well as an optimized piston top and appropriate combustion setup, resulted in an additional decrease in THC emissions of 50%. Advanced emission measurement equipments were needed for accurate screening of engine exhaust emissions (Figure 8). Regarding the gas direct injection tests, a Wärtsilä in-house design of a hydraulically actuated gas admission valve was finalized for the 2-stroke DF test engine. Validation of the same was completed at a test rig in Wärtsilä Switzerland. A successful demonstration of functionality of hardware was finally proven in engine tests. An overview of the test platforms is seen in Figure 9. Preliminary tests on the 4-stroke side were done on a 6L34SG engine (Figure 10) and utilising latest emission measurement technology as viewed in Figure 8 for accurate results verification and confirming potential of a direct gas injection technology.

Outline of work performed in WP2: Computer Aided Combustion Optimization
High numerical effort was undertaken in order to develop engine optimization strategies, starting from single part optimizations up to whole engine cycle. Heavy validation work was performed using single-cylinder and full engines, as well as test benches for special investigations. The testing included optical methods using Particle Image Velocimetry (PIV) / scattering on a flow-bench to investigate port flow and gas mixing on real engine size models. The investigations were performed by the project partner KIT. On a single-cylinder engine in MAN Diesel & Turbo (MDT) Augsburg, first optical images on a large-scale medium speed dual-fuel engine were performed in order to validate pilot ignition combustion models. Further on, investigations of multiple injections, extreme miller timings with advanced turbocharging, and cool combustion methods have been prepared and performed delivering insight into new combustion process strategies. The engine was used as well to validate the optimized engine parts. The MDT numerical work was performed mainly in Copenhagen and Augsburg. Numerous optimization strategies were developed for engine parts like ports, gas mixers, piston and nozzle configuration, combustion process etc. (Figure 11). Partner TUG developed a predictive 0-D combustion model for pilot-ignited gas engines including emission and knocking prediction. The models were validated using data from the single-cylinder engine in MDT Augsburg showing good model quality.

WP2 Achievements and Final Results
The newly developed optimization models have been tested on single-cylinder and full engines, showing significant reduction in testing time and improvement in engine specification (efficiency, emissions). For example, the on-site engine optimizer has been used to configure a fuel booster injection valve. The optimal engine setting was found fairly quickly having several g/kWh better specific fuel consumption than the reference from initial best guess (Figure 12). All investigated measures from four-stroke development (engine tests and numerical optimizations) were finally tested on the single-cylinder engine in MDT Augsburg (except PCCI). The outcome was a reduction of fuel consumption by roughly 2 %-points in gas mode under IMO Tier III emission legislation limits. As already mentioned, a high improvement potential comes from the extreme Miller timings in combination with the new turbochargers to come in near future.

Outline of work performed in WP3: Injection, Spray Formation and Combustion
Diesel combustion processes are strongly dependent on the rate of introduction of fuel and hence the quality of the atomization process, which in turn is significantly influenced by effects caused by the geometry of the fuel injection equipment itself, as well as the potential occurrence of cavitation. CFD investigations of the nozzle internal flow have been conducted with different simulation tools (considering cavitation) for different injector configurations, in particular taking nozzle eccentricities of actual large two-stroke engine injectors into account. Various laser measurement techniques have been applied for investigations of these injector configurations in an unique optically accessible test facility (spray combustion chamber) in order to allow the isolated study of the effect of key design parameters on fuel spray characteristics (evolution, morphology, droplet size and velocity) at relevant operating conditions. In addition, investigations of the subsequent ignition (delay, location) and combustion (flame lift-off) processes for various fuels (including HFO's) have been performed by means of the application of other advanced optical methods. Finally, the acquired experimental data was used in order to further develop and validate CFD-based tools with regard to spray and combustion modelling. The various experimental investigations performed yield in a comprehensive reference data set with regard to injection, spray formation and combustion based on which enhanced simulation capabilities could be established.

WP3 Achievements and Final Results
The CFD investigations of the nozzle internal flow have been conducted for different injector configurations as exemplarily shown in Figure 12. The results obtained with a custom tool using an advanced cavitation model in terms of velocity magnitude at the nozzle exit and flow recirculation intensity are different from those of incompressible single-fluid simulations performed with standard software – even though predicting general trends quite well. Various spray investigations have been performed in an optically accessible experimental test facility (spray combustion chamber – Figure 13) by means of optical techniques (shadow-imaging, Mie scattering) to the study the influence injector of in-nozzle flow and impact of design parameters in regard to spray evolution (penetration, deflection, angles). Furthermore, the advanced laser measurement technique Phase Doppler Anemometry has been applied which enables the acquisition of droplet velocity and size, notably also for lower fuel qualities (HFO's). The further use of combined chemiluminescence, incandescence and shadow-imaging measurements enabled investigations of the subsequent ignition (delay, location) and combustion (flame lift-off) processes for various fuels (including HFO's), as indicated in Figure 14. Combustion modeling (e.g. ignition, heat release, flame structure, soot distribution) has been carried on towards marine engine specific requirements. Benchmarking of preferred combustion models (ECFM) and comparison with a transient interactive flamelet model (DARS-TIF) were performed for different auto-ignition as well as liquid HFO properties (Figure 15, upper).A new method was introduced to identify and extract droplets in LES simulations of the primary breakup (Figure 16, left) which enables an enhanced analysis of the impact of geometric and thermodynamic boundary conditions on the spray formation. The influence of the atomizer nozzle and droplet disintegration was analyzed and major differences to existing assumptions were pointed out. The resulting influence on the spray – also according to experimental reference data – was directly considered in spray and combustion process simulations which led to a fundamental modification of the prediction of the thermal load on the combustion chamber components and the engine performance optimization (Figure 15, right; Figure 16, lower). Combustion modeling (e.g. ignition, heat release, flame structure, soot distribution) has been carried on towards marine engine specific requirements. Benchmarking of preferred combustion models (ECFM) and comparison with a transient interactive flamelet model (DARS-TIF) were performed for different auto-ignition as well as liquid HFO properties (Figure 16, upper).

Outline of work performed in WP4: Experimental and Modelling Studies of Fuel Injection Systems
Experimental rigs for visualization and measurements of two-stoke marine injection systems have either been modified or constructed from scratch. The rigs support visualizations and measurements of in-nozzle cavitation and flow as well as the visualization of the near-nozzle liquid spray. Momentum rate measurements on a hole-by-hole basis are also supported measured using force transducers. Together with efforts in designing optical transparent injector geometries different optical techniques were adapted to support near-nozzle and in-nozzle visualizations and measurements. The techniques used were shadowgraphy (Figure 17) and ballistic imaging for visualizing near-nozzle sprays and in-nozzle cavitation. The particle image velocimetry (PIV) technique (Figure 18) was used for measuring interior injector flow fields. Parallel to the experimental efforts, work has been performed in constructing a numerical model for the prediction of flow coefficients of injector nozzle holes. The model has been evaluated used experimental data acquired from the rigs. A prototype of an automated simulation pipeline with a minimum of user intervention has been developed.

WP4 Achievements and Final Results
Advanced optical techniques have been adapted to characterize near-nozzle sprays and in-nozzle flow. The techniques were used to
• estimate flow coefficients on a hole by hole basis using force sensors
• measure in-nozzle flow and visualizing cavitation using Particle Image Velocimetry and shadowgraph techniques, respectively
• visualize near-nozzle spray pattern utilizing ballistic imaging and shadowgraphy.
The experimental work showed that upstream geometry in the injector and the hole layout influences the produced spray, its deflection from its geometrical injection direction as well as the produced spray cone angle. A CFD model applicable for estimating flow coefficients in fuel valves on a hole by hole basis has been developed. The favourable evaluation of the model gives confidence that the model can be used in future injector development.

Outline of work performed in WP5: Integrated Emission Control Technologies
Concept studies and related simulations for flexible and integrated emission control were performed at Wärtsilä Finland (4-stroke engines) and at ABB TurboSystems (2-stroke engines). As result of the most promising future technologies towards future emission legislations were identified for realisation, as technology demonstrators. Development of flexible, integrated emissions control systems for 4-stroke engines, performed at Wärtsilä Finland, resulted in a technology demonstrator unit which combines SCR technology with 2-stage turbocharging(Figure 19). This technology demonstrator unit was designed and realized for a large bore medium speed engine based on the know-how collected from the earlier smaller scale tests with W6L20 2-stage engine. In parallel with the SCR tests feasibility testing of several EGR systems was performed, both at Wärtsilä Finland and at PSI. Development of flexible, integrated emissions control systems for 2-stroke engines, performed at Wärtsilä Switzerland, resulted in a technology demonstrator unit which combines 2-stroke DF-engine technology with 2-stage turbocharging (Figure 20). Power turbine was included in the design to improve fuel efficiency. Development of a new SCR control valve was done at Wärtsilä Finland. Development included intensive application of CFD and FEM. Technology demonstration tests were performed simultaneously with the testing of the SCR combined with 2-stage turbocharging, in order to have as realistic test conditions as possible. For investigation and testing of SCR operation with high sulphur fuel, test equipment was developed and realized at Wärtsilä Finland. Test equipment utilises side stream exhaust gases from laboratory engines, and includes exhaust gas flow measurement and CEMS. Work for the improved particulate reduction of scrubbers was done at Wärtsilä Finland. Field test equipment, including the novel ESP was successfully constructed during early phases of Hercules-C, targeting on collection of long term operation experience. Due to the lack of permission for operation from authorities, the tests never commenced.

WP5 Achievements and Final Results
During the concept study phase, vast amount of engine simulations were performed. As result, the most promising future technologies towards future emission legislations were identified for realization, as technology demonstrators. Simulations were later on validated with hardware tests, with good agreement. Testing of the large medium speed 4-stroke engine running SCR combined with 2-stage turbocharging first of all proved the system to fulfill IMO Tier III requirements, combined with practically no ammonia slip. Valuable test results have also been achieved from the effect of SCR on engine load acceptance. By optimising the SCR set-up and TC specification the time required to achieve engine full output could be reduced by a factor of 2~3. Major purpose of the tests was to gain experience of long term SCR operation with low quality fuels. Several alternative catalyst types were tested to collect information on fouling sensitivity. Tests proved that the current soot blowing equipment needs to be further developed to allow operation with increased catalyst densities. Testing 2-stroke DF-engine with 2-stage turbocharging proved the system to fulfill IMO Tier III requirements. Tests showed ultra low emissions combined with unchanged THC but reduced fuel consumption i.e. reduced CO2. Power turbine was implemented to further improve engine fuel efficiency. For the DF engine running in low-pressure gas mode 2-staged turbocharging offers a possibility to run with higher engine outputs and higher overall Mean Effective Pressure values without running risks of e.g. knocking. In diesel mode which normally suffers from the low compression ratio available, the higher scavenge air pressures allow compression pressures and thus firing pressures similar to what is run on normal 2-stroke diesel engines, which brings down the BSFC levels considerably without sacrificing IMO Tier II NOx compliance. Several EGR lay-outs were tested to validate simulations and to enable ranking of the various alternatives. As one example, the “semi-short” route EGR system was tested at PSI (Figure 21). Test showed that IMO Tier III emission limits can be achieved for the weighted 4 load point average, by applying charge air and EG management simultaneously. Tests duplicated however also the results from simulations, reduction in NOx comes with a remarkable increase in both fuel consumption and soot formation. The compact SCR control valve testing confirmed the expectations from CFD-calculations to be true, single compact valve can replace the traditional 3-valve system. Flow characteristics of the valve are adequate for proper control of the flow. In addition, the single valve system is safer from the system and engine operation point of view, since it deletes risks originating from erratic operation sequence when controlling several valves. An SCR bench has been developed for the purpose of validating the SCR process for high sulphur fuels (Figure 22, 23). The needed minimum exhaust temperature has been investigated with the SCR bench. Based on the test results, the minimum SCR temperature for high sulphur fuels is to be above 330°C for avoiding deactivation in long term operation. Operation with high sulphur fuel requires periodic turbocharger washing, SCR reactor soot blowing and SO3 formation determines catalyst optimization. These properties were examined together with ITSCR testing on the 6L46F engine. Testing proved that soot blowing needs to be further developed and during turbine washing the SCR has to be bypassed.

Outline of work performed in WP6: Near Zero Emission Combustion and DPF Technologies
In Subproject (SP) 6.1 MAN Diesel & Turbo SE, Augsburg, and PBS Turbo s.r.o. developed and delivered electrically driven EGR blowers with speed control by a frequency converter for both, 2- and 4-stroke diesel engines. A turbocharging system involving compressor map width enhancement and variable turbine geometry has been further advanced and delivered. Several inlet valve alloys, coatings on charge air piping and other corrosion protection measures such as exhaust gas piping made of high-alloy steel regarding their suitability for an EGR engine have been tested. Finally tests on 6L32/44 common rail (CR) two stage (TS) engine featuring an electric turbo blower (ETB)12 blower running at variable speeds with constant EGR flap position as well as variable EGR flap position at constant blower speeds have been performed (Figure 24).
In SP6.2 the Laboratory of Marine Engineering (LME) at the National Technical University of Athens (NTUA) modified a turbocharged medium speed marine diesel engine, in order to trigger compressor surge during steady state engine operation, by injecting compressed air inside the engine intake manifold, downstream of the compressor. Instrumentation for fast measurements of compressor and engine operating parameters during surge cycles, including hot wire anemometry at compressor inlet wheel for measurement of air velocity to the compressor has been developed and installed (Figure 25). A surge model has been developed and incorporated into a detailed engine simulation code for the prediction of total powertrain performance during compressor surge.
In SP6.3 MAN Diesel & Turbo SE, Augsburg, and Tehag Engineering AG, conducted a DPF concept study under consideration of exhaust gas, fuel and lube oil parameters typical for marine medium speed diesel engines. A test matrix for DPF substrates and coatings was set up for substrate variant selection and pre-evaluation of coatings on a synthetic hot gas test bench. The pre-evaluation revealed a performance ranking for suitable coating variants as well as for the substrate variants. From these results the final layout of an advanced DPF test system could be determined. The test engine has been further optimized for minimal PM emissions. The DPF test system was manufactured and installed at the engine test bed. DPF engine tests, measurement of stationary cycle points as well as off-cycle and transients have been performed and the performance of a long term DPF technology prototype could be assessed (Figure 26).
In SP6.4 MAN Diesel & Turbo SE, Copenhagen, and Danfoss IXA A/S, matured an in-situ CO2 and H2O EGR sensor technology and developed and designed an application of the system directly on the engine. The system was tested at a test engine with special regards to the vibration isolated application technique for sensitive electronic control technology. A Just-in-Time Water-in-Fuel (JiT WiF) pump system was designed manufactured and tested on both, test rig and test engine. For the development of a new engine running mode for electronically controlled engines with challenging technologies like EGR and WiF the pressure rise (Prise) as design limit was challenged and evaluated through tests of pressure behind and between piston rings. The new engine running mode has been developed and tested at the test engine with EGR and WiF for maximum emission reduction of NOx along with other pollutants.

WP6 Achievements and Final Results
By the provision of advanced two-stage turbocharging in SP6.1 with enhanced compressor stability involving optimized variable turbine area geometry at the high-pressure turbocharger and with EGR blower with speed control achieved by a frequency converter (Figure 24 & 27 left), a switch between IMO Tier-II and -III yielded >80% NOx reduction (Figure 24 right). A definition of engine involving two-stage turbocharging and switchable EGR blower for IMO Tier II-III compliance could be validated.
In SP6.2 a fully instrumented experimental arrangement (Figure 25 left) for investigations of compressor surge and a detailed thermodynamic engine simulation code for prediction of compressor and engine performance during compressor surge (Figure 25 right) was delivered. The surge model in conjunction with the engine simulation code can now be used for the design of control systems for surge avoidance.
In SP6.3 the US-EPA PM limit of 0.04 g/kWh could be met (Figure 26 left) for operation according to US-EPA conditions with ultralow sulphur diesel (ULSD) fuel, while a PM reduction of 50% mass was achieved by the advanced DPF system. A gravimetric PM reduction efficiency >95% as reported from automotive/NRMM could never be achieved when DPF was applied to marine medium speed diesel engines. The performance of a DPF technology prototype was assessed even under transient operation (Figure 26 right) and key issues for the layout of a long-term DPF technology prototype have been identified.
In SP6.4 NOx emissions could be lowered drastically by the use of combined EGR and WiF technologies (Figure 27 right), but with fuel penalties. The in-situ CO2 and H2O sensors (Figure 28 middle & right) showed the potential for controlling the EGR process as well as JiT-WiF (Figure 28 left) was found a potential technology for fast mixing of fuels. Improved system and technology understanding through tests of mechanical boundary conditions yielded to a combined use of EGR + WiF with a new engine control strategy.

Outline of work performed in WP7: Advanced System and Plant Control
The focus of this work package has been to study how to control and diagnose engine processes and systems utilizing the latest advances in process control and diagnostic theory. NTUA has been looking at hybrid engine tests and their control. Both adaptive and model-based control approaches have been studied for the control of an engine/water brake/electrical motor in a Power Take In – Power Take Out (PTI/PTO) setup. The results from the engine tests showed significant improvements during extreme transient conditions when utilizing the electric motor, both with respect to emissions and torque response. The adaptive control approach, specifically the Model Reference Adaptive Control (MRAC) approach, proved to have its benefits, but is still not suitable for general industrial use.
At Aalto University a set of adaptive control methods have been studied with the aim to find robust adaptive control methods that can be applied on production engines without the need of support from experts. The control methods were adopted for the control of the EGR valve. The control methods have been validated in simulations tests and the intension was to also perform here full-scale engine validations. However, due to mechanical issue on the EVE engine at Aalto University, these tests were not done. Validation of the set of controller was performed in simulations which anyway provides us with a fundamental understanding of the behaviour and needs of these controllers. At ETH, the issue of knock modeling and control has been studied. Based on literature studies existing models of the knock phenomenon have been used and further developed in order to enable a better understanding of the process. The developed knock models have been first of all tested on automotive engines and then in full-scale engine tests on a medium-speed W34DF engine with promising results. Due to some changes in the organization, the final tests using the models for control were left undone. Cylinder pressure based fault diagnostics and control have been in focus at Wärtsilä. Robust calculation of Indicated Mean Effective pressure (IMEP) have been studied and developed, especially with respect to truncation errors and sensor biases. Based on the calculated IMEP, methods for identification misfire and control of consecutive misfires has been developed and tested in full-scale engine tests. IMEP has been moreover used for balancing the cylinder-wise outputs in order to get the engine running as smoothly as possible. The developed algorithms have been tested extensively at the engine laboratory in Vaasa with good results. The main application is for cycle-to-cycle misfire detection, but can also be applied on cylinder balancing. In additional to this, control of an engine-SCR system has been studied where the questions has been, how the total system should be controlled optimally. By combination of both exhaust-gas temperature and SCR control, optimal operation of the total system can be achieved. This approach has been tested in the engine laboratory with good results.

WP7 Achievements and Final Results
Main achievements for the WP 7 are development and evaluation of:
• various adaptive controller schemes for industrial use
• controls from a system perspective
• fuel combustion diagnostics and control
Adaptive control schemes have been available for many years, but despite this, adaptive control has not been widely adopted for industrial use. The main reason is the issue of guaranteeing stability in all operating points. To investigate this issue and the current state of the art on internal combustion engines, an effort has been made to evaluate various adaptive controller approaches to better understand their potential. In Figure 29 an example of model-reference adaptive control scheme applied on the control of the manifold air pressure is depicted. The conclusions from these tests are that adaptive control can be applied but not without considering the specifics of the process to be controlled. Usually it is beneficial to – instead of controlling each sub-process individually – considering the whole system. The idea is that by considering the limits and dynamics of the various sub-processes, it is possible to optimally control the total system. In this work package two systems have been considered
; 1) engine + SCR and 2) hybrid engine with PTI, cf. Figure 30. The studies have not been considering the control of the whole system, but on multiple sub-processes. The argument for this is the time limitation of the project and that this anyway addresses the overall question and will anyhow indicate on the benefits. Full-scale engine tests showed on significant results especially for the hybrid engine system during transients (Figure 31). Here the emission and smoke peaks normally seen could be almost eliminated during extreme transients. Regarding fuel combustion diagnostics and control, a method for detecting abnormal situations, such as weak and misfiring, in the cylinders has been developed. The method is based on calculation of the Indicated Mean Effective Pressure (IMEP). In addition to this, a cylinder knock model has been developed and validated in full-scale engine tests.

Outline of work performed in WP8: Intelligent Engine
Regarding the development of a cylinder individual control setup, a comprehensive analysis of pressure data was performed by FEV in cooperation with MDT. The goal was the definition of the requirements for the pressure based control algorithms. Based on these results, an engine model was set up in GT Power and various control approaches were tested. In a final step, the control setup was implemented on a test engine at MDT and validated.
For the development of health monitoring technologies, a market study was performed and compared with requirements for health monitoring of marine diesel engines. Together with MDT, a sensor for cylinder liner wear detection was developed by TU Graz and tested in the laboratory as well as on a running test engine. Finally, algorithms for the prediction and assessment of engine performance were developed by NTUA. A marine two-stroke engine was modelled in the software MOTHER and various tests run, for example whether the simulation yields plausible results, whether the simulation can help to optimize the running parameters of the engine and how engine faults may be detected through these methods.

WP8 Achievements and Final Results
The cylinder individual control algorithms were successfully implemented and tested on a 6L32/44CR engine at MDT Augsburg. The tests showed a good behaviour of the control system with fast reaction times and good stability (Figure 32). A significant reduction of fuel consumption of up to 3g/kWh was shown to be attainable. A rollout of this technology as a serial product is planned. Furthermore a sensor for measuring cylinder liner wear based on ultrasound technology was developed and also tested in the project (Figure 33). The sensor demonstrated the ability to perform liner thickness measurements with good repeatability even under adverse conditions (temperatures, vibrations of engine at full load). Further long term field tests are planned in order to fully validate the capabilities of the sensor.
The performance prediction algorithms developed in the project showed that the selected test engine could be modelled reliably with the simulation environment. Results from the simulation were in good accordance with field measurements. It was demonstrated that these simulations can be used to optimize engine performance, for example by determining optimal Start-of-Injection-timings. Furthermore, the effects of certain engine faults were modelled and their influence on engine performance quantified (Figure 34).

Outline of work performed in WP9: Cylinder Lubrication Concept for Optimized Emissions
This Work Package focuses on enhancing tribosystem performance and at the same time reduce lubrication system related contributions to the exhaust gas composition of large two stroke marine diesel engines.
During the project efforts were undertaken in disciplines such as
- Rig testing
- Computational simulation tool development and validation
- Measurement technology development
- Full scale engine testing
The first phase of the project focused on theoretical investigations to address lube oil consumption mechanisms. For this purpose, investigations on possible contributors to this topic nominated major contributors which were investigated in detail as a prerequisite to most effectively enhance tribosystem performance. The determination of single contributors of the lube oil balance comprises detailed analyses with regards to piston ring pack design, lubricator design and the introduction of lube oil re-circulation cycle. The validation of the new lubrication concept was performed utilizing the RTX-4 test engine in a full scale engine test. An overview of performed work is given in Figure 35.

WP9 Achievements and Final Results
Lube oil consumption reduction, being the key driver for this project discloses the optimization potential of single tribosystem components. Intensive investigations on theoretical aspects related to the establishment of a lube oil balance reveal main contributors to focus on. This report thus describes tribosystem component optimizations on basis of technology development in general, comprising intensive rig as well as engine testing, computational simulation tool development and the development of monitoring technologies to address an appropriate performance of the new lube oil re-circulation concept. Lube oil evacuation grooves were introduced to reduce lubrication losses due to the piston ring pack spray which expands a flow consisting of combustion gas and accumulated lubricant into the piston underside in a highly uncontrolled way. Testing of lube oil evacuation groove performance was conducted to quantify related lubrication losses and at the same time validate the assumptions which were made in designing a simulation tool to predict the evacuation process which initiates the main process of the lube oil re-circulation cycle. A typical lube oil evacuation groove performance simulation result is shown in Figure 36. A comparison between measured and predicted results show very good correlation which indicates that the assumptions made in setting up the simulation model are applicable for further design optimizations. The development of a lube oil property monitoring system is based on an optical measurement approach to quantify relevant lube oil parameters related to lube oil degradation. The general approach of designing such a system comprises:
- Lab-testing, utilizing a FTIR-spectrometer to perform reference measurements of several oil-samples
- To derive correlations between spectral ranges and typical lube oil properties
- To reduce the spectral range down to corresponding wavelength of interest
- Develop an oil-flow-cell with dedicated optical transmission characteristics
Characteristic effects on parameters related to lube oil degradation were found in mass concentrations of soot and sulfates of the lube oil. Concentrating on a certain wavelength allows designing a lube oil flow cell comprising the application of an optical filter to simplify the procedure of accessing relevant lube oil properties in real time.
The purpose of investigating on lube oil injectors and the lubrication system in general, is based on the requirement of injecting the lubricant in a highly flexible and accurate manner. The lubrication system is designed to comply with tribosystem requirements to reduce lubrication losses to the minimum. Lab experiments support the development of a lube oil spray simulation tool taking into consideration lubrication system boundary conditions and their influence on lube oil spray pattern and impingement on the cylinder liner surface. Results of this investigation clearly demonstrate the possibility to create a lube oil spray in the desired shape by continuously adjusting the injection pressure. The dataset which was elaborated during this investigation is used to further enhance the predictive capability of the spray model which is applied on the lube oil spray simulation tool. Piston ring pack optimization is based on results from extensive rig testing, as well as full scale engine tests and the consequent application of the piston ring pack simulation tool, which was further developed during this project. The main focus of recent investigations was laid on piston ring profile effects on hydrodynamics as well as on lube oil transportation characteristics. Rig testing focuses on the determination of:
- Hydrodynamic boundary conditions as a function of lube oil properties and piston ring profiles
-Piston ring profile effects on lube oil transportation and distribution characteristics
Results of this investigation yield a clear determination of hydrodynamic limitations with regards to piston ring profile effects on the lube oil film build up. Furthermore investigations clearly demonstrate the possibility to control lube oil transportation characteristics. Shaping piston ring profiles hence, must be considered a crucial design parameter when looking at designing piston ring packs. The key validation approach which is used to quantify lubrication concept effects on the exhaust gas composition of a full scale engine test is based on the real time acquisition of SO2 concentrations in the exhaust gas following oxidation mechanisms of sulfur species originating from fuel and lubricant. The application of this measurement system shows a highly sensitive response to lubrication system parameter variations and therefore can be considered a very precise tool to determine the impact of the new lubrication concept on the exhaust gas. Figure37 shows a comparison between the standard lubrication concept with the modified one that was evaluated in a full scale engine test. Tribosystem performance of the new lubrication concept was intensively tested in order to determine single contributors to a total sulfur balance over the engine which can directly addressed to lubricant fractions in the exhaust gas. Results in this context clearly demonstrate a superior functionality of lube oil distribution in vertical direction which reduces the amount of lubrication losses by app. 40%.

Outline of work performed in WP10: Advanced Bearing and Combustion Chamber Technology
New combinations for liner- and piston ring surfaces to reduce friction and particulate matter emissions (PM) and to increase reliability were tested. For the piston rings new coatings made with physical vapour deposition (PVD), thermal spray (HVOF) and galvanic coating were chosen. For the liners new honing surfaces and coatings made with Plasma Transferred Wire Arc (PTWA) – technique were developed. For these candidates pre-validation on test-rigs were carried out (Figure 38).
Candidates determined during pre-evaluation were evaluated in a full engine test. A test procedure was defined considering both running-in and the necessary measurements for friction and particulate matter emissions. After the measurements were conducted, the results were evaluated. The new combinations were compared with the standard installation (Figure 39). The emission behaviour was rated by the PM-emission which were measured on a fully equipped engine at different load points (Figures 40, 41, 42). The Main bearing power loss was investigated using numerical tools and the characteristic values were extracted. In order to do more realistic simulations some new features were added to the simulation package. The new tools were developed and implemented into the standard simulation package of predicting bearing performance. The incorporation of these advanced tools was validated using a new test rig (Cavitation Test Rig - Figure 43) and an existing test rig (Fatigue Test Rig – Figure 44). A simulation of the power loss for a 12G80ME-C9.2 was carried in order to show the potential of the new design.
Thermally insulating the combustion chamber components may be beneficial from a performance point of view and this was investigated. It was found that insulation of the cylinder cover was the most desirable in relation to lowering the thermal loss and ensuring that SFOC was kept as low as possible. A literature survey followed by a sample study revealed the most promising (Thermal Barrier Coating) TBC candidate. The TBC was applied to a cylinder cover for the 4T50ME-X research engine located at MDT (Figure 45). An experimental program was carried out in order to investigate whether TBC could be a future way to lower the heat loss from the combustion process. The measurements conducted were compared to a reference measurement which was conducted prior to the installation of the TBC-cover. The results showed that the thermal loss could be lowered by 5%.

WP10 Achievements and Final Results
Suitable candidates for low friction and wear operation of piston ring-cylinder liner contact were determined by laboratory testing. The laboratory tests showed that piston ring friction could be lowered by >10% (2-stroke) and 20% (4-stroke) using a new combination of piston ring and cylinder liner materials and treatments. These candidates also showed a reduction in PM up to 2/3 and SFOC was lowered in an engine test verification.
Theoretical parametric studies of piston ring geometry revealed a optimization potential >8% and piston skirt investigation revealed a 21% potential (simulation). The journal bearings were thoroughly investigated from both an experimental and a theoretical point of view. The implementation of new advanced simulation tools (TEHD and MC add-on) revealed that the main bearing power loss could be reduced by 11 % in average without exceeding the capabilities of the bearing coating, which was also investigated. The fatigue properties of selected bearing coatings were established. Finally the average cylinder cover temperature was reduced by about 5% at maximum load (~ 15°C).

Potential Impact:
Contribution towards impacts listed in the Workprogramme.
The overall vision of the HERCULES research programme is for sustainable and safe energy production from marine power plants. The technological themes of the HERCULES initiative, since its inception in 2002, have been “higher efficiency”, “reduced emissions” and “increased reliability” for marine diesel engines. The HERCULES programme aims to push the limits of marine engine know-how. The focus of the HERCULES programme is on the development of future generation of optimally efficient, clean and reliable marine powerplants.
In I.P. HERCULES (A) (2004-2007) ( large-scale research platforms were established, with the main objective on screening the potential of a broad range of emission reduction technologies, in which area great improvements were achieved. In HERCULES-B (2008-2011) ( the quest for reduction in emissions was retained, focusing on several specific novel technologies, but at the same time more importance was placed on improved efficiency, hence reduced fuel consumption and CO2 emissions.
For a further step in marine engine technology towards improved sustainability in energy production and total energy economy, an extensive integration of the multitude of identified new technologies is required. The Project HERCULES-C (2012-2015), addressed this challenge by adopting a combinatory approach for engine thermal processes optimisation, system integration as well as engine reliability and lifetime. HERCULES-C aimed towards marine engines able to produce cost-effectively the required power for ships throughout their lifecycle, with responsible use of the natural resources and respect of the environment.
The HERCULES-C objectives for the year 2015 (i.e. by the end of the project) are depicted in Figure 5.

- The First Objective of HERCULES-C was to further reduce fuel consumption of marine engines by 3% (over the BAT 2010) and thus reduce the CO2 emissions further. HERCULES-C targeted the improvement of engine efficiency through the deeper understanding of the fuel injection and combustion processes and optimal engine control. Modelling tools were further developed and validated through specialized experimental facilities providing optical access to full scale operating marine engines.
- The Second concurrent Objective was to reduce marine diesel engine exhaust emissions by 80% over the IMO Tier I limits, towards near-zero levels. To achieve the emissions objective the best technologies developed in the preceding projects I.P. HERCULES (A) and HERCULES-B were combined and integrated.
- The Third Objective was to retain the marine engine powerplant performance at the almost “As-New” level, allowing only 5% divergence over the lifetime (20 years) of the plant. To achieve the objective of maintaining the as – new engine performance, developments in sensors, condition assessment and adaptive control methods were used, in conjunction with materials tribology and lubrication improvements.
The scope of the Project included the technology interrelations needed for a holistic approach to marine engine efficiency improvement, emissions reduction and reliability increase. Specifically, work was performed in the following areas:
• Multi-fuel switching and direct gas injection technologies
• Partially premixed combustion
• Low temperature, cool combustion with extreme Miller valve timing plus Exhaust Gas Recirculation
• Visualization methods for flow inside fuel injection nozzles
• Laser optic methods for fuel spray field investigation inside full scale working engine
• Combustion analysis and modelling tools validated through full scale experiments.
• Sequential Aftertreatment Units including SCR, Scrubber and Electrostatic Precipitator.
• Advanced multistage sequential turbocharging schemes.
• Combination of Exhaust Gas Recirculation and Water-in-Fuel Techniques.
• Engine Thermal Process adaptation with adaptive control for extreme operating conditions.
• Overall engine adaptive control combining individual cylinder controls
• Operating behaviour evaluation algorithms and model based diagnostic methods.
• Emission optimised lubrication.
• Methods of friction reduction in bearings, piston rings, skirts
• Vessel powerplant monitoring and asset management.
The integrated RTD work in these areas including analysis, simulations, design, development and prototype testing, as well as selected full scale testing, allowed the above HERCULES-C objectives to be achieved concurrently i.e. to be obtained simultaneously.
Therefore, the Project HERCULES-C addressed very well the challenges of Workprogramme ACTIVITY 7. 2. 1. “The greening of surface transport in the area of maritime transport.”
In specific, the HERCULES-C project contributed directly to individual Expected Impacts included in the Workprogramme for the AREA: “The greening of products and operations.”

(1… Contribution to CO2 reduction emissions from surface transport operations aligned with new policy targets as set out in the Climate and Renewable Energy Package of 2009. In the short to medium term (before 2020) reducing greenhouse gas emissions by 10% compared to 1990 levels. Beyond 2050, reducing greenhouse gas emissions through domestic and complementary international efforts by 25 to 40% by 2020 and by 80 to 95% by 2050 compared to 1990 levels …)
The First Objective of HERCULES-C was to further reduce fuel consumption of marine engines by 3% (over the Best Available Technology 2010) and thus reduce the CO2 emissions further. Achieved within the project was 1% from Low temperature Combustion (WP1), 1% from DF-engine optimizations (WP1), 2% from Combustion optimization (WP2) and 1.5% from Intelligent engine / Advanced plant control (WP7) as well as from Pressure based cylinder-individual control, health monitoring technologies (WP8).

(2… Reduction of exhaust and local emissions to reach near-zero-emission levels in view of the compliance with future legislation at European and international levels and to allow national and local authorities meet their air quality engagements …)
- The Second concurrent Objective was to reduce marine diesel engine exhaust emissions by 80% over the IMO Tier I limits, towards near-zero levels. To achieve the emissions objective, the best technologies developed in the preceding projects I.P. HERCULES (A) and HERCULES-B were combined and integrated. Achieved within the project was 50% reduction for Particulate Matter (PM), 50% reduction for Total Hydrocarbon (THC) and 80% for NOx, through contributions from DF-engine optimizations (WP1), EGR - Gas operation on EVE (WP1), Combustion optimization / multi-fuel (WP2), Aftertreatment (DPF, EGR) (WP6) and Charging (VGT) (WP6).

(3…Proposals must ensure at least a neutral impact on climate change …)
To the extent that CO2 production and emissions from thermal powerplants contribute to climate change and the performance of plants generally deteriorates with age, then all HERCULES-C Work Packages were related to this Expected Impact.

European Added Value and Strategic Significance
Marine diesel engine developments require a multidisciplinary approach and has traditionally been an area where Europe leads the world. Based on the successful results of the FP6 Integrated Project I.P. HERCULES (A), by a consortium of 42 organizations and the FP7 Project HERCULES-B with 32 organizations, led by the two world leading European marine engine manufacturer company groups, MAN and Wärtsilä, it was agreed to proceed to Phase III of the work, as already conceived in 2002, retaining the technological themes of higher efficiency reduced emissions and increased reliability for marine engines, taking technology a step further towards improved sustainability in energy production and total energy economy, aiming also for an extensive integration of the multitude of new technologies identified in the previous Phases I and II.
In the HERCULES-C consortium, the two major partner groups MAN Diesel & Turbo (Augsburg), MAN Diesel & Turbo (Copenhagen), Wärtsilä (Finland), Wärtsilä (Switzerland), cover together about 90% of the world’s marine engine market (medium- and low-speed engines). All the other industrial partners are top companies in the world market, with several of these industrial partners being the world’s leader in their field. The participating Research Institutes and University Laboratories are renowned worldwide for research excellence in their field.
The HERCULES programme has shown that market competition does not preclude common approaches towards issues of world significance such as the environment, the sharing of aims and the cooperation to tackle such issues. The participation in common meetings of persons at the highest management level in the two groups, the presentation of achievements in plenary technical sessions, the re-appraisal of common targets based on all results, has served to foster mutual respect and understanding of different views.
At the same time, the economical aspect of keeping European industry competitive is a shared concern of both leading participants.
The tie-up of these European world-leading Organisations and the integration of research capacities, in a research Programme of such magnitude and long term scope, aiming at specific objectives with strategic impact of global significance, exemplifies the European dimension of cooperative R&D research excellence.
The main European added value of the HERCULES Programme is that in no previous occasion a grouping of this magnitude has ever been assembled in marine engine RTD, pooling scientific / technological capacity and material resources and large-scale experimental facilities, with a common vision in developing ultra-low emissions efficient reliable marine engines. In the majority of cases there have been previous bilateral cooperation links between partners, but it is important to note that 10% of the partners participated for the first-time in a shared-cost RTD proposal for European Community support. Cutting edge research networking was inherent in the project, since there are 7 large-scale engine test facility sites, 7 University Laboratories and 3 Research Institutes taking part in the Project.
It must be stressed that the HERCULES Programme has been the de facto world reference R&D activity in marine diesel engines for the past 11 years (2003-2014) with wide coverage in the Mass Media (Technical Press, TV, web) and was also presented in the “Star Projects” category of the series “Success Stories” of EC/Research/Info. Centre.
The Programme HERCULES has already liaised with the following National and International authorities and organisations directly contributing to the Emissions Standards formation procedure:
EUROMOT: The European Association of Internal Combustion Engines is a non-profit Organisation of ICE manufacturers in Europe. EUROMOT is in dialogue with legislators in Europe and worldwide.
CIMAC: The International Council on Combustion Engines, is a worldwide Association of manufacturers, users such as ship-owners, utilities, classification and research institutes in 19 Countries in Europe, Asia and America and publishes CIMAC Recommendations, which reflect common industry positions.
EPA: The mission of the U.S. Environmental Protection Agency is to protect human health and the environment. EPA works to develop and enforce environmental regulations.
MEPC/IMO: The Marine Environment Protection Committee is part of the International Maritime Organization (IMO) that is the United Nation specialized agency with responsibility for the safety and security of shipping and the prevention of marine pollution by ships.

The strategic significance of HERCULES was primarily in three areas:
• Preserving and improving the competitiveness in an area of European Industrial supremacy and success, namely marine propulsion engines.
The participation of the two major European Marine Engine manufacturing groups which together hold 90% of the world marine engine propulsion market, cooperating with major component suppliers, will reinforce the position of these companies in the world market. By collaborating in R&D both with competitors and cooperating firms, within an appropriate structure and with management systems in place to guarantee control over the outcome, firms can derive large mutual benefit.
• Reducing air pollution from ships, benefiting society in general.
(… In the world there are 53,000 ships of size larger than 2,000 tons, and about 1000 new-built ships per year. Diesel engines account today for 99% of ship powerplants. A ship’s life is 20+ years. A typical large marine engine on a merchant ship will operate during this period for more than 150,000 hrs. A ship will achieve approximately 0.02 KWh/( energy consumption which is 10 times more efficient than road transport of the same goods. During the same period this typical single marine engine of assumed output 25,000 KW, with a maximum efficiency of about 50%, the highest of all thermal powerplants, will consume 500,000 tons of fuel and will produce 60,000 tons of NOx, 2,000 tons of CO and 3,500 tons of particulates, all from the lifetime of a single powerplant…)

The vision of HERCULES, of drastically reducing emissions and at the same time increasing of engine efficiency and thus reducing of CO2 emissions (as well as retaining the engine performance in the as-new condition over the lifetime of the powerplant), will potentially affect the vast majority of ships (new-buildings and through possible retrofit technology also existing ships). It will therefore have a significant societal implication of worldwide effect.
Improving shipping industry competitiveness through marine engines of reduced fuel consumption and increased reliability
Europe is both the greatest user and the most important provider of shipping services, with a beneficially owned fleet representing around 30% of world tonnage. The functioning of international shipping is therefore of major importance to the European shipping industry and to Europe as a competitor and consumer in world services and products markets. In terms of external trade, 90% of total exports of the European Union is transported by sea. One major ship operating cost is in the engine fuel cost, which may be 60-80% of the total life cycle cost of an engine. It must be noted that for an average size containership, 1% reduction in Specific Fuel Consumption means 300,000 USD lower fuel costs per year. Therefore specific fuel consumption will remain a strong selling point. Thus, the vision of HERCULES to increase marine engine efficiency, hence reduce fuel cost as well as increase reliability, retaining lifetime powerplant performance, complies with the users demands and will improve the shipping industry’s competitiveness.

Main dissemination activities of the HERCULES-C Project

HERCULES-C web-site
The HERCULES-C official website ( has been the main gateway for publication and dissemination of the results and progress of the Project. General information about the programme can be gained through the Public Area of the website, which consists of the following categories: Structure, Partners’ details, News, Progress updates and publicity information, such as articles, presentations, publications etc. The Progress updates section was refreshed every 6 months with summaries of developments in every Work Package of the Project. In addition, access to Public Deliverables is open to the public through the HERCULES-C website. A table with the public Deliverables can be found in Figure 46.

As depicted in the table of Figure 47, 28 scientific publications have been produced from the work of HERCULES-C. These papers refer to important achievements of the Project and have been presented in Congresses, Conferences and Meetings worldwide.

HERCULES - C in Press and Media
Before the official start and throughout the HERCULES-C Project, several articles have been published in the international press about the Project, its partners and its aims. A list of these articles is found beneath in Figure 48.

Presentations of the overall Project Results
Apart from the presentations that describe achievements of separate objectives in individual Work Packages, there have also been general presentations that offer an overview of the progress of the Project. A presentation, titled "HERCULES A-B-C, A 10-year Major R&D Effort Towards the Next Generation Large Marine Diesel Engines" was delivered in the Transport Research Arena 2012 (TRA2012). TRA is an event that aims at exploring the most advanced research works and innovations, the latest technological and industrial developments and implementations, and innovative policies in Europe and worldwide. In September 2012, a similar presentation, describing the overall aims and progress of the project was delivered by the Project Coordinator in the Future Combustion Engine PowerPlant (FCEP) – Seminar, which took place in Helsinki, Finland. An overview of the HERCULES R&D programme was also presented in the 27th World CIMAC Congress, which took place in Shanghai, May 2013. This event, which takes place every 3 years, is of great importance, as it has worldwide recognition and is attended by more than 1000 international experts in the field of large engine research. The paper referred to all the milestones that have been achieved during the whole HERCULES Project, as well as the latest accomplishments of the HERCULES-C programme. A presentation, titled "HERCULES-1: The long term (2004-2014) R&D programme on large engine technologies for ships" was delivered in the Transport Research Arena 2014 (TRA2014).

Final Partners’ Forum - Conference
In the Final Partners’ Forum, the Plenary session, which included presentations by the Coordinator and the Work Package Leaders, was webcasted to the public in order to disseminate the results and achievements of the Project. In addition, a Round table panel discussion on the subject “Limits to marine engine efficiency” was webcasted as well. The round table discussion offered insights into the subject of marine engine efficiency and emissions and the Project’s contribution.
The Plenary Session and the Round table panel discussion can be accessed in the following link

Exploitation of HERCULES-C project results
HERCULES-C was an interdisciplinary RTD project of wide thematic spectrum, since engine development requires parallel progress in many technological fronts. The project consolidated the breakthroughs and the technologies proven successful in I.P. HERCULES (A) and HERCULES-B, considered further potential breakthroughs in several technologies as well as integration of identified new technologies. In all cases, the aim was to go beyond the state-of-art and by definition this could only be achieved through innovations.
Such innovations within HERCULES can be widely classified in 3 categories and relate to all Work Package Groups:
1) Basic scientific concepts or primary technology
2) Component or system prototypes
3) Prototype application experimental test installations

The overall Project expected outputs, suitable for commercial exploitation, were the following:
• Complete next-generation marine engines of higher efficiency and ultra low emissions, encompassing the successful technologies developed during the project.
• Components and subsystems reaching test prototype form during the project, which can be further developed as commercial products for the new-building or retrofit market in ships.
• Design methodologies and software tools to be incorporated into computer-aided engineering products for engines and processes.

The major partners, engine makers and component suppliers, are in the business of manufacturing and selling engines as well as licensing engine and component designs. The commercial exploitation of all successful developments within the HERCULES-C is therefore assured.

The table included in Figure 49 provides an overview of the potential Exploitation Items as included in Annex 1of the Grant Agreement, stemming from the RTD work within the various Work Packages and also an indication of the time span (short/medium/long) to exploitation. In relation to this table, HERCUES-C Project achieved to produce the following items for potential exploitation, categorized on a per Work Package Group (WPG) basis:

For WPG1 “New Combustion Concepts”, Advanced dual fuel gas engines with low temperature and partially premixed combustion and valving strategies for IMO Tier III have been developed; the “cool combustion” concept for the 4-stroke EVE engine is depicted in Figure 50, while the “low temperature combustion” concept which was realized for a 2-stroke engine with Direct Water Injection (DWI) is shown in Figure 51. Optical probes in a multi-fuel single-cylinder engine have also been developed and tested as shown in Figures 52 and 53. Combustion strategies compatible with aftertreatment methods (SCR, DPF) were achieved by model-based combustion optimization (Figure 54).

For WPG2 “Fuel Injection Models & Experiments”, a large series of models for flow and cavitation applicable to large engine injectors have been developed and tested, as presented in Figures 55 to 58.

WPG3 “Near–Zero Emission engine technologies” has produced a large series of items suitable for commercial exploitation i.e. combined SCR and scrubber units (Figure 20 and Figure 59, showing the sequential SCR concept with 2-stage turbocharging), complete variability of turbocharging system combined with EGR equipment (Figures 20, 22, 24 and 27), Particulate Filters (DPF) and regeneration techniques for marine fuel including desulfurization & ash handling (Figures 60 and 61) achieving substantial reduction of PM emission (Figures 26 and 61), as well as combined WIF (water-in-fuel) and EGR as shown in Figures 27, 28 and 62.

WPG4 “Adaptive engine control & lifetime reliability”, aimed for the combination of individual engine subsystem controllers to overall adaptive control, as shown in Figures 29 and 32, as well as for sensors for wear detection integrated in health monitoring system, a prototype of which is depicted in Figures 33 and 63.
WPG5 “New Materials & Tribology” has also produced a large series of items suitable for commercial exploitation i.e. Low friction and wear engine piston rings, for example modified piston ring packs (Figure 64), new lube oil injectors (Figure 65) and lube oil re-circulation grooves (Figure 66). Further, Increased performance main engine bearings have been developed and tested as shown in Figures 43, 44 and 67. Thermal Barrier Coatings for piston crowns have also been developed and tested (Figure 45).

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