Patent ID: 8549900

Claim:
A device for estimating the state of gas in a gas passage provided in an internal combustion engine, comprising: first estimation means for estimating a time-course change in the mass of gas in the gas passage through application of a mass conservation law to the gas in the gas passage; second estimation means for estimating a time-course change in the temperature of the gas in the gas passage through application of an energy conservation law to the gas in the gas passage; and third estimation means for estimating the pressure of the gas in the gas passage on the basis of the mass of the gas obtained through iterative integration of the estimated time-course change in the mass of the gas with respect to time, the temperature of the gas obtained through iterative integration of the estimated time-course change in the temperature of the gas with respect to time, and a gas state equation which is applied to the gas in the gas passage and which includes a term regarding the volume of the gas passage.