Volume estimating method for combustion chamber of variable compression ratio internal combustion engine e.g. petrol engine, of motor vehicle, involves estimating volume of chamber based on rotation angle of crankshaft

摘要

The method involves estimating compression ratio by a measuring units, and estimating a volume of a combustion chamber (3) based on rotation angle of a crankshaft (6), for given compression ratio, by decomposition of the volume into a Fourier series. Fourier series coefficients are calculated or estimated based on the estimated compression ratio or vertical position of the crankshaft. A variation of the compression ratio is realized by an actuator (13). An independent claim is also included for a device estimating a volume of a combustion chamber of a variable compression ratio internal combustion engine comprising an estimating unit.