An Experimental Study of Dieseline Combustion in a Direct Injection Engine

Abstract

The differences between modern diesel and gasoline engine configurations are now becoming smaller and smaller, and in fact will be even smaller in the near future. They will all use moderately high compression ratios and complex direct injection strategies. The HCCI combustion mode is likely to lead to the merging of gasoline and diesel engine technologies to handle the challenges they are facing, offering a number of opportunities for the development of the fuels, engine control and after-treatment. The authors' recent experimental research into the HCCI combustion quality of gasoline and diesel blend fuels has referred to the new combustion technology as 'Dieseline'. It is found that this kind of fuel blend provides some unexpected benefits to the expansion of the operating window and reduction of hydrocarbon emissions in HCCI engines, and these benefits include extended low misfire limit, increased engine stability, reduced peak cylinder pressures and reduced emissions within the whole HCCI operating window. It was shown that the lean limit of lambda can almost reach up to 2.0 when the engine is operated with moderate compression ratios. It is shown that the combustion of the blended fuel offers promise to the desired ignition quality, which reduces the dependence of HCCI on EGR trapping or intake heating for a wide range of CR. The HCCI operating region for the unheated NVO can be significantly extended into lower IMEP values and the audible knocking is restrained to the highest values of air fuel ratio at high load boundary for the highest mixture temperatures. Copyright ©2009 SAE International.