Patent ID: 8078389

Claim:
A method of determining a combustion characteristic for an internal combustion engine from an accelerometer signal, said method comprising the steps of: (a) operating a calibration engine, equipped with a calibration sensor and a reference accelerometer sensor, at a predetermined operating condition and using said calibration sensor to detect said combustion characteristic and said reference accelerometer sensor to collect a reference accelerometer signal; (b) correlating said combustion characteristic with said reference accelerometer signal and storing correlated data in a calibration table where it is associated with said predetermined operating condition; and (c) equipping an engine with an accelerometer sensor, said calibration table, and an electronic engine controller, whereby when said engine is operated at said predetermined operating condition, said electronic engine controller can determine a real-time combustion characteristic by collecting a real-time accelerometer signal from said accelerometer and cross correlating with said correlated data stored in said calibration table.