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2022
Conference Paper
Titel
Virtual Development of a New 3-Cylinder Natural Gas Engine with Active Pre-chamber
Abstract
The path to the decarbonization of transport sector goes by the integrated use of different technologies, including natural gas engines, which represent an immediate and cost-effective solution in cutting CO2 emissions, thanks to the higher H/C ratio compared to commercial fuels. However, the engine design faces a number of challenges including the need for power density, cold start, combustion efficiency, emissions, while remaining profitable for application in commercial vehicles. With these constraints in mind, a consortium of different partners tackled the development of such an engine, financed by BMWI and resulting in a project called MethMag.
Considering a gasoline engine of comparable power targets as a benchmark, the virtual development led to the design of a new combustion chamber, high-tumble channels, and a new piston, after optimization of the valve strategy, by using a full-variable valve train. In addition, different injector positions, and injector types were evaluated. Direct injection below intake valves was selected in combination with an active pre-chamber. The last was specifically designed for this engine, with an hollow-cone conventional gasoline injector and cooling possibility. The investigation of the different design combinations was possible using the fast response 3D-CFD-Tool QuickSim, developed at FKFS.
The resulting single-cylinder engine is currently being manufatured, and it will be installed at Fraunhofer ICT for validation and further refinement. Following the performance prediction of the first manufactured geometry, the engine can operate ultra-lean up to λ ~ 1.8, with indicated efficiency higher than 42%.
Author(s)