COMBUSTION CONDITION DETERMINATION DEVICE FOR INTERNAL COMBUSTION ENGINE

PROBLEM TO BE SOLVED: To provide a combustion condition determination device for an internal combustion engine capable of more accurately determining combustion condition. SOLUTION: The combustion condition determination device for the internal combustion engine is provided with a means detecting cylinder pressure of a combustion chamber, a means detecting crank angle, a calculation means calculating volume of the combustion chamber based on the detected crank angle, an intake air quantity detection means detecting quantity of intake air flowing in from an outside as fresh air, a means estimating internal intake air quantity not detected by the intake air quantity detection means, and an estimation means estimating motoring pressure by an operational expression including the calculated volume, the detected intake air quantity, and the estimated internal intake air quantity. The device determines combustion conditions based on a relation between pressure estimated by the estimation means and the detected pressure corrected by the correction means in combustion stroke, and by the correction means correcting detected cylinder pressure according to a correction expression and a means identifying parameters of the correction expression to minimize error of pressure estimated by the estimation means and the detected pressure corrected by the correction means in compression stroke. COPYRIGHT: (C)2009,JPO&INPIT