Gm Global Technolgoy Operations, Inc.

Robert M Storwick

Mark K Krage

John H Lienesch

A method and apparatus for determining diesel engine fuel injection timing. While a diesel engine is running a microwave signal is supplied to the combustion chamber thereof and the reflected signal is detected. The combustion chamber is supplied with fuel by an outwardly opening poppet type injector. The reflected microwave signal has an asymmetric portion which is produced when the injector poppet opens to inject fuel. The method and system of this invention detects the occurrence of the asymmetric waveform and relates it to the top dead center position of the engine.

Means for establishing timing in diesel engines using microwave

While the crankshaft of an internal combustion engine is rotating, an encoder device produces a reference signal pulse and a series of encoder signal pulses during each crankshaft revolution and a microwave signal of a substantially constant amplitude and frequency is coupled through a microwave probe into the combustion chamber of a selected reference cylinder of the engine. The microwave signal waveform reflected from the reference cylinder combustion chamber while the reference cylinder piston approaches, passes through and moves away from the top dead center position during the compression and power strokes is processed to determine the encoder signal pulse count at which the line of symmetry thereof, the piston top dead center position, occurs. Initial ignition timing angle is then set relative to the encoder signal pulse count corresponding to the piston top dead center position.

Growing community of inventors

Rochester, MI, United States of America

Robert M Storwick