抄録
Homogeneous Charge Compression Ignition (HCCI) engine has attracted attention for its high heat efficiency and low emissions. But the fuel research is necessary because the ignition timing relies heavily on fuel. Additionally octane number cannot be applied for HCCI engine because of broad operation condition such as intake air temperature, engine speed and intake O_2 concentration. Wherein index of HCCI engine (HCCI index) is developed and confirmed that it can be applied for variety operation conditions.
