Patent ID: 6595043
Filing Date: 2003-07-22
Classification: F02D,G01M

Abstract:
A method for diagnosing an engine, the method comprising the steps of:(a) linking manifold absolute pressure (MAP) to in-cylinder pressure during calibration of the engine such that a table results; (b) collecting a single in-cylinder pressure measurement during real-time operation of the engine; (c) determining combustion quality for the engine based on the real-time in-cylinder pressure measurement and the table; (d) determining a real-time ratio based on the real-time in-cylinder pressure measurement and a real-time MAP measurement; (e) matching the real-time MAP measurement to an entry in the table having a calibration MAP measurement that is approximately equal to the real-time MAP measurement; and (f) dividing the real-time ratio by a calibration ratio corresponding to the entry, the calibration ratio being based on a calibration in-cylinder pressure measurement and the calibration MAP measurement such that a combustion quality calculation results.