Estimation of Cylinder Compression Using the Transient Rotational Speed of Flywheel

In this paper authors propose a new method for estimation of cylinder compression. Under motoring condition, when the transient rotational speed fluctuation of flywheel within a working cycle has been measured, the Max. compressive pressure of each cylinder were calculated based on the principle of inertia acceleration.

The testing results of 4 and 6 cylinder engines show that, the measured errors were within ±3%, so it is a proper tool for fast estimation the compression of engine mounted on vehicles especially.