Patent ID: 7440841
Filing Date: 2008-10-21
Classification: F02D,G01M

Abstract:
1. A method of determining a pressure-based combustion parameter for a cylinder of an IC engine, comprising the steps of: pre-calculating engine crank angle dependent volume data for said cylinder and storing said volume data as a function of engine crank angle for later retrieval; measuring pressure in said cylinder at scheduled engine crank angles during a combustion cycle of said engine; retrieving stored volume data for said cylinder based on said scheduled engine crank angles; calculating the pressure-based combustion parameter using the measured pressures and the retrieved cylinder volume data; and calibrating the scheduled engine crank angles such that a resolution of the pressure measurements has relatively low resolution of pressure measurement during intake and exhaust strokes of the combustion cycle, and relatively high resolution of pressure measurement during the compression and power strokes of the combustion cycle.