Development of a basis for control of combustion in an internal combustion engine.

摘要

This work is composed of several distinct sections however the focus is to effect engine control. The first effort represents quantification of flow during individual cycles and the development of a method which can be used to define the cycle-to-cycle variability in pre-combustion phase of a four stroke cycle. It was determined that one could uniquely describe this phase of the airflow or fuel-air mixing by evaluating the probability density function of normalized circulation. Of particular significance was the identification that cycle-resolved measurements are needed to accurately describe pre-combustion air motion and fuel-air mixing phenomena and that simulations which rely on ensemble-averaged Navier-Stokes equations cannot provide reliable indications necessary for combustion control in an internal combustion piston engine. It was the result of these experiments that inspired development of theoretically based methods which would provide insight into an algorithm for an engine control for the governor system.; This effort led to the two new concepts related to the events which occur during the conversion of reactants to products before and during the work producing segments of the four stroke cycle. We term these segments the dynamic stage of combustion and the exothermic stage of combustion. Mathematical analysis are constructed which uniquely define the bounds of these stages of combustion and provide a rational basis for developing future engine controls. The majority of the effort described in this dissertation is orientated to developing these potential control algorithms and of a description of what is termed the effectiveness of combustion. Based on these continuously differentiable algorithms, the rate of conversion of reactants to products and the rate of change of the conversion of reactants to products can be obtained. Results of this analysis have been applied to a stratified charge methanol fuelled engine. In the future, these methods can be integrated in microprocessor controls and will provide the feedback necessary to control the next generation of internal combustion engines.