Technical Paper
A Study of a Gasoline-fueled Compression Ignition Engine ∼ Expansion of HCCI Operation Range Using SI Combustion as a Trigger of Compression Ignition ∼
2005-04-11
2005-01-0180
A new combustion concept, called spark-ignited compression ignition (SI-CI) combustion, is proposed for expanding the operation range of homogeneous charge compression ignition (HCCI) combustion. The authors previously showed that raising the mixture temperature before compression so as to induce auto-ignition near top dead center reduces the quantity of trapped gas, resulting in a lower maximum indicated mean effective pressure (IMEP). With the newly proposed combustion concept, auto-ignition of a homogeneous lean mixture is accomplished by the additional compression resulting from SI combustion of a small quantity of stratified mixture instead of raising the intake air temperature. This SI-CI combustion process reduced the necessary increase in intake air temperature compared with conventional HCCI combustion. A higher maximum IMEP was achieved with SI-CI combustion than with conventional HCCI combustion, as was planned.