METHOD OF ESTIMATING STATE QUANTITY OR TEMPERATURE OF GAS MIXTURE FOR INTERNAL COMBUSTION ENGINE

摘要

The present apparatus calculates a mass ma (mass ratio ma/mf) of mixing-gas-forming cylinder interior gas, which is a portion of cylinder interior gas to be mixed with a forefront portion of injected fuel vapor having a mass of mf, on the basis of a predetermined empirical formula. Subsequently, under the assumption that heat exchange with the outside does not occur, the apparatus calculates an adiabatic gas mixture temperature Tmix of the gas mixture forefront portion on the basis of the heat quantity of the fuel vapor having a mass of mf and the heat quantity of the mixing-gas-forming cylinder interior gas having a mass of ma. Subsequently, in consideration of an amount of heat that the gas mixture forefront portion receives from peripheral cylinder interior gas mainly via a circumferential surface thereof, the apparatus estimates a final gas mixture temperature Tmixfin of the gas mixture forefront portion (i.e., the temperature of the gas mixture) in accordance with the equation Tmixfin=Tmix (1-Kex) + Ta Kex, where Ta represents cylinder interior gas temperature, and Kex represents a heat exchange coefficient (0 < Kex < 1).