Effect of Jet Ignition on Lean Methanol Combustion Using High Compression Ratio

Significant reductions in vehicle carbon dioxide (CO2) emissions are required to meet fleet targets and this is increasing the interest in new combustion concepts for internal combustion engines. There is also an increased focus on the use of renewable fuels to reduce environmental impact. This study focusses on the use of methanol as an internal combustion engine fuel. Methanol is a liquid fuel that is readily produced from waste bio-matter, as well as synthetically using renewable energy, and is proposed as a primary energy vector in hard-to-decarbonise sectors, such as Marine, but could be equally applicable to road transportation.In this study, the MAHLE Di3 engine, which is a highly boosted 3-cylinder gasoline direct injection engine capable of operating at over 30 bar BMEP, has been modified to include MAHLE Jet Ignition technology, in both passive and active configurations, as well as utilising a very high compression ratio to maximise thermal efficiency. The paper will compare the performance and emissions of the engine using a spark ignition baseline and both passive and active jet ignition configurations.The technology combinations described enable brake thermal efficiencies of over 42% at lambda 1 and over 44% when operating lean. Measurements are presented showing thermal efficiency and engine out emissions using all three ignition technologies, relative to a gasoline baseline. It is concluded that the resulting combination of technologies, when used with methanol, represents a cost-effective route to achieving very high engine efficiency and a significant reduction in engine-out emissions compared to gasoline operation combustion engine.