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High efficiency engine r&d on combustion with ultra low emissions for ships (Hercules)

Final Report Summary - HERCULES (High efficiency engine R&D on combustion with ultra low emissions for ships)

The 'High Efficiency Engine R&D on Combustion with Ultra Low Emissions for Ships' (HERCULES I.P.) project developed new technologies to drastically reduce gaseous and particulate emissions from marine engines and concurrently increase engine efficiency and reliability, hence reduce specific fuel consumption, CO2 emissions and engine lifecycle costs. The focus of the HERCULES I.P. was on the development of future generation of optimally efficient, clean and reliable marine powerplants.
The I.P. HERCULES specific objectives were defined in terms of percentage changes related to current Best-Available-Technology in-service (BAT-IS), for shipboard prime movers, with at least one marine engine installation reference worldwide in 2003.

The project objectives were approached through interrelated developments in thermodynamics and mechanics of 'extreme' parameter engines, advanced combustion concepts, multistage intelligent turbocharging, 'hot' engines with energy recovery and compounding, internal emission reduction methods and advanced aftertreatment techniques, new sensors for emissions and performance monitoring, adaptive control for intelligent engines. Advanced process models and engineering software tools were developed, to assist in component design. Prototype components were manufactured and rig-tested. Engine experimental designs were assessed on testbeds to validate the new technologies and confirm the achieved objectives. Full-scale shipboard testing of chosen systems demonstrated the potential benefits of next-generation marine engines.

Integrated work has been performed in the following areas:
- Thermo-fluid dynamics of combustion engine processes.
- Internal (in-engine) measures for emissions reduction as well as external measures (aftertreatment of exhaust gases).
- New methods for high pressure air charging with multistage intelligent units, allowing engines with extreme values of operating parameters, to increase engine efficiency.
- Use of microelectronics and advanced control for engines, optimally adaptive to different conditions, including adverse operation and failure compensation over the lifetime of the powerplant.
- New primary sensors and signal analysis software, allowing much more detailed research investigations in engine processes, as well as increased precision and fidelity for continuous realtime monitoring in service.
- Powerplants for extremely emissions-sensitive shipboard applications (ports with minimum NOx and smoke emissions).

The Consortium included engine makers, component suppliers and equipment manufacturers, compounded by renowned universities and research institutions, as well as, world-class shipping companies. From the participants 60% were industrial partners, 19% were universities, 12% were research institutions and 9% were shipping companies. Substantial social engineering was required to enable the joint participation of all these organizations and especially the two engine maker Groups MAN and Wärtsilä, who were leading the project. Proper arrangements in information flow had to be in place to ensure that the tactical development aims of each company would be preserved. The Management of the project ensured that while the R&D work of each engine manufacturer remained confidential so as not to compromise competitiveness and market position, the compliance to project objectives and project final results were jointly evaluated.

The project was structured into several work packages (WP), as follows:

WP 1: Extreme design parameters
This work package included a study of the influence of advanced working cycles on engine performance and emissions, finding design and material solutions for engine components operating under extreme conditions and performing full-scale and rig tests to evaluate the technologies.

WP 2: Advanced Combustion Concepts
To examine new concepts and methods for improved combustion requires the development of sufficiently accurate combustion and chemical kinetics sub-models, accounting for the larger length and time scales and the lower error tolerance of large combustion chambers of low rpm engines. Fundamental experimental investigations including in-cylinder measurements are also needed to validate such models, to extend currently available CFD tools, so that they can be used with confidence in design of combustion chambers and prediction of emissions. Thus, Workpackage 2: Advanced Combustion Concepts included model development, validation experiments and simulation of combustion processes and emission formation.

WP 3: Multistage / Intelligent turbocharging
To obtain charging pressures beyond today's state-of-art, presupposes developments in turbochargers. The requirements are higher pressure ratios and wider flow range, with higher turbocharger efficiency. To that effect, variable geometry compressors and turbines were examined in Workpackage 3: Multistage/Intelligent turbocharging. Multiple stage turbocharging with intercooling, power-take out (at high loads) power-take-in (at low loads), electrical compounding systems and very high pressure ratio single stage compressors, were the technologies examined. Prototypes were designed and tested on test rigs and on test engines. New concepts for variable - geometry turbocharging were also studied and developed.

WP 4: Turbocompound engine / hot engine
Engine compounding seeks to optimise the overall efficiency by better utilisation (recovery) of exhaust gas energy. Several types of compounding systems were installed onboard ships in the early eighties. The increased capital investment for the recovery systems and the added complexity, made the option unattractive in periods of cheap fuel. Compounding involves not only steam combined cycles, but also power take in/out systems and the use of engines with limited cooling so as to increase exhaust gas energy. In Workpackage 4: Turbocompound engine/hot engine, the concepts were revisited in view of several recent technological developments.

WP 6: Emission reduction methods (internal-water)
Internal engine emission reduction methods relate to influencing the closed cycle process and affecting the in-cylinder temperatures. Two broad technological approaches are considered in the WP6 and WP7 which can provide good cost-effectiveness: Water introduction and Exhaust Gas Recirculation.

WP 7: Emission reduction methods (Internal-EGR)
The exhaust gas recirculation has been used for many years in smaller engines for NOx reduction, since the larger heat capacity of the exhaust gas leads to reduced mean cycle temperatures. However the heavy fuel used in marine engines leads to substantial difficulties when considering EGR. Workpackage 7: Emission reduction methods (Internal-EGR) considered the viability of using EGR in marine engines operating on variable quality fuel. Prototype systems were developed for two- and four-stroke test engines. Models of particulate formation in heavy fuel combustion were developed, to be used in simulation tools supporting the hardware design and development. Particulates and soot measurement methods for marine engines were developed and used to characterise exhaust gases.

WP 8: Emissions aftertreatment
After treatment of exhaust gases can be considered either as a standalone option for engine emissions reduction or in conjunction with various internal methods. The whole package must be appropriate for the engine operating profile and fuels used and must comply with the cost effectiveness and reliability requirements for marine engines. Several advanced exhaust gas aftertreatment methods were studied in Workpackage 8: Emissions aftertreatment. Additionally, enhanced emissions measurement technologies have been studied resulting in prototype systems developed and tested on laboratory test-engines.

WP 9: Reduced friction engine
A means to increase the engine overall efficiency is to reduce parasitic losses. Reduction of engine friction requires developments in tribology, components and lubrication. In Workpackage 9: Reduced friction engine, rig tests and fired engine tests with extensive instrumentation, together with elastohydrodynamic bearing calculations, provided appropriate background information. New designs for piston rings, liners and bearings, valve trains and fuel injection system components have been developed, supported by advanced calculation methods. New 'smart' materials (shape-memory alloys, magnetic-shape-memory, piezoelectric, magneto-restrictive materials and coatings) are of interest here for applications to both today's conventional engines and in future extreme parameter engines.

WP 11: Adaptive engine
The computer controlled marine engine dispenses with mechanical camshaft driven units for fuel injection and cylinder valve systems, introducing instead independent servo units. Thus the engine has wide adjustment and performance optimisation potential, since operational characteristics can be adapted to prevailing engine operational conditions and component wear. Workpackage 11: Adaptive engine, aimed at the realisation of adaptive engine controllers and systems. This requires firstly an advanced monitoring system with reliable sensors for sampling and handling many parameters, so as to serve the feedback loop of control. A self-learning system with parameter evaluation procedures has been developed to provide control schemes enabling goaloriented engine performance. The complete system has been tested on test bed engines as well as on an electronic engine on-board ship. Appropriate engine electronics and actuators for engine operating mode changes have been developed.

Throughout its lifetime, the HERCULES project demonstrated excellent progress and cooperation between the partners, despite the size and complexity of its structure.
The HERCULES project 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.
Regarding results from the HERCULES project, several prototypes were completed and are already running and several onboard demonstrations have been completed. Some impressive results have been attained. A wide portion of the marine diesel engine R&D spectrum is addressed in the project and the results show that the project goals were fully met by the end of the project. The Project has resulted in more than 30 patent applications.