Conventional Event Based Engine Control

Many existing production engine controllers use event (or constant crank angle increment) based sampling and computation systems. Because the engine events are synchronized to the internal physical processes of an engine, it is widely accepted that this is the most logical approach to engine control. It is the purpose of this paper to deal with this assumption in detail and to illuminate various failures of it in practical systems.

The approach of the paper is in terms of overall general control system design. That is to say that the problem of event based engine control is considered as a general control problem with its standard components: 1. modelling (engine plus actuator/sensor), 2. specification of desired performance goals, 3. control system design method selection and 4. experimental testing. It is shown that transport and computation delays, system pumping fluctuations (state noise), sensor/actuator characteristics and available design methods make event based systems somewhat less attractive than intuitive preconceptions would indicate. Moreover the insights obtained in the detailed study suggest that some improvements of conventional event based control systems are possible.