Closed-loop control of a diesel engine

摘要

The method involves generating a fuel command for an engine cylinder in accord with an operator fuel request, determining a desired air inlet rate to the engine cylinder responsive to the fuel command as the air inlet rate estimated to provide the beneficial air/fuel ratio for the generated fuel command, and generating air inlet rate error as the difference between the desired air inlet rate and an estimated actual air inlet rate. An open-loop desired EGR quantity is determined in response to the fuel command as an estimate of the quantity of recirculated engine exhaust gas needed to dilute air admitted to the engine cylinder to provide the beneficial air/fuel ratio. The method also involves sensing a predetermined set of engine parameters indicative of an engine operating level, selecting an EGR gain value from a stored schedule of gain values as the one of the stored schedule of gains values corresponding to the sensed predetermined set of engine parameters, determining an EGR gain adjustment value as a predetermined function of the air inlet rate error and of the open-loop desired EGR quantity, varying the selected EGR gain value by the determined EGR gain adjustment value, and generating an EGR command.