A Simple Method of Analysis and Modeling of Cycle-to-Cycle Variation of Engine Work - the Example of Indicated Pressure

The paper presents a simple method of analyzing and modeling the cycle-to-cycle variation of engine work. The method is based on the dependence between parameters of consecutive cycles. The author proposes applying an additional forgetting factor that defines to what extent the previous state of the object (i.e. the analyzed or modeled value) affects its present state. The paper outlines a method of determining this factor's value on the basis of signal analysis. A method of modeling a process of any configuration of three parameters: mean value, standard deviation and forgetting factor is described. Finally, the paper presents the results of cycle-to-cycle analysis of mean effective pressure variation in the function of spark advance of the IC engine working in idle speed. A method of interpreting the results is proposed, allowing for symmetry of the process analysis: forward and back in time.