AIR-FUEL MIXTURE STATE QUANTITY ESTIMATING METHOD OF INTERNAL COMBUSTION ENGINE AND AIR-FUEL MIXTURE TEMPERATURE ESTIMATING METHOD

摘要

PROBLEM TO BE SOLVED: To provide an air-fuel mixture temperature estimating device (a method) of an internal combustion engine for accurately estimating the air-fuel mixture temperature constituted of injected fuel (fuel vapor) and a part of cylinder gas mixed with the fuel.;SOLUTION: This device calculates mass ma (the mass ration ma/mf) of an air-fuel mixture forming cylinder gas being a part of the cylinder gas mixed with a forefront part of the fuel vapor of injected mass mf based on a prescribed empirical formula, and calculates the adiabatic air-fuel mixture temperature Tmix of the air-fuel mixture forefront part, on the assumption that there is no heat exchange with an external part, based on a quantity of heat of the fuel vapor of the mass mf and the quantity of heat of the air-fuel mixture forming cylinder gas of the mass ma. By taking into consideration heat transfer mainly received to the air-fuel mixture forefront part via an outside surface A from peripheral cylinder gas existing in its periphery, the final air-fuel mixture temperature Tmixfin (that is, the temperature of an air-fuel mixture) of the air-fuel mixture forefront part, is estimated from an expression composed of Tmixfin = Tmix × (1-Kex)+Ta × Kex, using the adiabatic air-fuel mixture temperature Tmix, the peripheral cylinder gas temperature Ta, and a prescribed heat exchange factor Kex (0 Kex 1).;COPYRIGHT: (C)2005,JPO&NCIPI