An On-Line Engine Roughness Measurement Technique

Engine roughness may be characterized by nonuniform torque production among the cylinders of a multicylinder reciprocating internal combustion engine. This paper presents a technique for the on-line measurement of engine roughness based on fluctuations in engine crankshaft speed resulting from variations in torque production from cylinder to cylinder. The resulting roughness measure is suitable for use in a variety of engine control or diagnostic applications. The use of engine crankshaft speed information as the basis for the roughness measurement technique eliminates the need for any additional hardware beyond that found on conventional microprocessor-based engine control systems.