System for monitoring and/or controlling multiple cylinder engine

Abstract

Engine crankshaft speed signal, comprising pulses produced by a toothed wheel and sensor, has portions monitored to develop separate instantaneous cylinder associated power output vector signals for each engine cylinder. Engine knock is detected by comparing actual variations in each cylinder power signal with expected variations. Each vector cylinder power signal is multiplied by different first and second weighting vector signals to provide first and second scalar signals indicative of cylinder performance with respect to first and second different cylinder performance criteria, respectively. These scaler signals are compared to each other and a balancing of cylinder power is achieved by adjusting the amount of fuel delivered to each individual cylinder. Preferably, fuel adjustment is implemented such that the average fuel delivered to the cylinders prior to adjustment, determined in accordance with exhaust pollution level, will equal the average fuel delivered after adjustment. Knock detection is provided without using any additionall knock sensor since the existing crankshaft speed sensor signal is used. The generated individual cylinder power vector signals, by use of different weighting vectors, allow detection of several different faults or other performance criteria for each cylinder. Balancing cylinder power is achieved while fuel consumption is maintained in accordance with desired exhaust pollution levels.