DME HCCI 엔진에서 분사방식에 따른 연소 특성

Abstract

Intake/exhaust valve timing and exhaust cam lift were changed to control the internal exhaust gas recirculation (IEGR) and homogeneous charge compression ignition (HCCI). To measure the IEGR rate, in-cylinder gas was sampled during from intake valve close to before ignition start. The lower exhaust cam made shorter valve event than higher exhaust cam and make IEGR increase because of trapping the exhaust gas. IEGR rate was more affected by exhaust valve timing than intake valve timing and increased as exhaust valve timing advanced. In-cylinder pressure was increased near top dead center due to early close of exhaust valve timing. Ignition timing is more affected by intake valve timing than exhaust valve timing in case of exhaust valve lift 8.4㎜ while ignition timing is affected by both intake and exhaust valve timing in case of exhaust valve 2.5㎜.