Results-driven Hercules research project in third phase

16 Oct 2013
Hercules-C will benefit advanced medium speed engine design as well as two-stroke development

Hercules-C will benefit advanced medium speed engine design as well as two-stroke development

With the European marine engine research project Hercules well into its third phase, David Tinsley looks at how it can achieve its goals of near-zero emissions and further significant drops in fuel consumption.

With the third phase of the largest and most ambitious collaborative research programme ever conducted into marine engine technology development now underway, the EU-sponsored Hercules-C project complements the drive for further major reductions in fuel consumption and attainment of ‘near-zero’ emissions with goals relating to lifecycle performance.

The pan-industry Hercules endeavour started in 2004 with the Alpha project, and was continued from 2008 until 2011 under the Beta phase. Securing quantifiable advances in the efficiency and environmental standard of marine diesels have been the overarching themes from the outset. One of the main arguments for prolonging the studies into Hercules-C, with its three-year timescale to 2015, was the need for integration of the wealth of different engine technologies identified under Hercules-A and Hercules-B, and for the development of new optimisation techniques and solutions.

Hercules-B is widely credited with having brought selected technologies along the path towards product applications, and Hercules-C is taking that process further while drawing the various strands of work together into optimal solutions and integrated systems.

Key aims of the C project are to achieve a 3% reduction in engine fuel consumption by 2015 and 5% by 2020 in relation to best available technology (BAT) in 2010, and an 80% diminution in emissions by 2015 and 95% by 2020, as compared with BAT for 2010. A companion objective is for engine performance to diverge by no more than 5% from ‘as new’ over a 20-year plant lifetime. The latest stage accordingly gives added pragmatism to the undiminished scientific goals.

With 22 partners from industry and academia, plus three shipowners serving as ‘external associates’, Hercules-C has an overall budget of €17m($22.5m), with €9m($12m) being contributed from public funds via the EU’s Seventh Framework Programme. As before, overall technical leadership in the latest phase is being provided by MAN Diesel & Turbo and Wärtsilä, with the co-ordinating role retained by Professor Nikolaos Kyrtatos, director of the Laboratory of Marine Engineering at the National Technical University of Athens (NTUA), one of the partner organisations represented in Hercules from the beginning.

In a presentation (Ten Years After: Results from the major programme Hercules A-B-C on marine engine R&D”, by Nikolaos Kyrtatos (NTUA), Lars Hellberg (Wärtsilä), and Christian Poensgen (MAN Diesel & Turbo), to the 2013 CIMAC Congress in Shanghai, it was explained that the current research phase adopts a combinatory approach, integrating the multitude of new technologies identified in Phase I and Phase II, with the accent on engine thermal process optimisation and system integration, as well as engine reliability and sustained through-life performance. Information from the paper is used here with permission of CIMAC.

The building blocks of Hercules-C are the various sub-projects, numbering 47, each of which is further divided into several activities. A cluster of related sub-projects makes up a Work Package (WP), whereby 10 cover the various technical tasks, three serve administrative needs, and a pair of related WPs constitutes a Work Package Group(WPG).

The project encompasses five WPGs spanning a broad spectrum of marine engine R&D. The WPGs conduct R&D in parallel and exchange high-level information throughout the project. The partner companies, organisations, institutes and universities work in groups at sub-project level, with specific targets. Work is consolidated into WPs, and reported with written deliverables or presented as machinery prototypes. Dissemination of results is the function of one of the project’s three non-technical WPs.

The main thematic areas under Hercules-C, and reflected in the WPG structure, are new combustion concepts, fuel injection and fuel spray models and experiments, near-zero emission control technologies, adaptive engine control and lifetime reliability, and new materials and tribology (friction and lubrication) optimisation.

Investigations into advanced combustion strategies and computer-aided combustion optimisation embrace a wide range of tasks and tests including direct injection gas combustion, multi-fuel engine efficiency and fuel switching, combustion improvement at low temperatures, partially pre-mixed concepts, new design tools, optimised engine components and, for four-strokes, innovative combustion strategies to meet IMO Tier III limits.

Another of the WPGs is concerned with the development and application of experimental and computational techniques to the study of fuel injection systems in large marine diesels. This encompasses laser optical methods for examining in-nozzle and near-nozzle flow fields, the visualisation of fuel spray under engine operating conditions, and the validation of CFD (computational fluid dynamics) models. Key tasks for the research partners include the development of transparent fuel equipment and associated test rigs, optical in-nozzle diagnostics of flow and cavitation, optical diagnostics of fuel jets, and related numerical tools.

Among the expected results of this sphere of Hercules-C research is a greater understanding of fuel spray characteristics, propagation and cavitation at conditions relevant to marine two-stroke diesels, and a CFD model capable of predicting cavitation in atomisers and other parts of the fuel and hydraulic systems.

The research consortium’s drive for emissions abatement to an unprecedented level of effectiveness is expressed in work on the development and integration of advanced control technologies systems. This encompasses diesel particulate filter (DPF), selective catalytic reduction (SCR), scrubber, water-in-fuel and exhaust gas recirculation (EGR) methods, and combinations of different techniques. Anticipated results include further emission reductions through the use of two-stage turbocharging in conjunction with the latest flexible fuel injection and air introduction systems, the viability of various system combinations and assessment of the ultimate emission reduction potential from the integration of technologies, and the applicability of automotive DPF concepts to large medium-speed diesel engines.

The complex area of studies addressing advanced engine control and ‘intelligent’ systems to foster lifetime reliability features the development of on-line optimisation methods and health monitoring, model-based diagnostic tools, thermal management, and adaptive control applying individual cylinder algorithms. The level of the self-imposed challenges represented in the project is implicit in a set of expected outcomes which include engine performance prediction algorithms and the development of an integrated sensor for wear detection.

Eight of the Hercules-C participants are engaged in studies relating to new materials and cylinder friction, lubrication and wear. Research is directed at reducing lube oil losses and related emissions, developing low friction bearings and piston rings, and a lube oil recirculation concept with health monitoring.

Among the raft of anticipated results is the development for two-stroke applications of a piston ring pack and lubrication system as a single coherent unit, for optimised lubrication and reduced particulate emissions. Also sought is a model of the temperature distribution in the lubrication oil film, to assist in future main bearing design, and the introduction of automotive technologies to large-bore four-stroke diesel engines to reduce friction and wear.

The scheduled completion of the C project in 2015 will represent the culmination of about 11 years of studies and total financial resourcing of €76m ($101m) under the Hercules programme.

The Hercules-A project, conducted between 2004 and 2007, set a new benchmark for cooperation in marine engine technology research, drawing in 42 participants from 10 countries. The Alpha phase had a total budget of €3m ($44m), of which €15m ($20m) was covered by the EU under the Sixth Framework Programme, together with €2.5m ($3.3m) provided by the Swiss government. The 2008-implemented Hercules-B project, initiated in 2008 with a three-year timescale, was fulfilled by 32 partners on a budget of €26m ($34.5m). Authorised for support under the Seventh Framework Programme, this also received €15m ($20m) in EU funding.

Although less in actual amount, the public money allocated to Hercules-C is of a similar proportional order to that invested in the Beta project, at more than 55%. EU sponsorship is predicated on the potential long-term environmental contribution resulting from improved engine design and on issues relating to the maintenance of European technological and industrial competitiveness.

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