Control method and control system for engine EGR (exhaust gas recirculation) and VGT (variable geometry turbocharger)

Abstract

The invention relates to a control method and a control system for engine EGR (exhaust gas recirculation) and VGT(variable geometry turbocharger), comprising the following steps of 1) arranging a sensor, a VGT executer, an EGR executer and an engine management system; 2) prearranging target values of supercharging pressure, a target value of single-cylinder air-feeding quantity, openness and default openness of open-loop control of a VGT and an EGR, PI (product improve) closed ring arithmetic parameters, upper limit and lower limit of oil quantity, and upper limit and lower limit of rotating speed under all working conditions; 3) according to a sensor signal, obtaining pressure target values and a air-feeding quantity target value by an optimum control target module, obtaining practical measurement values by a practical control target module, judging whether an engine is in the working condition applicable to or not applicable to the closed ring control by a state monitoring module, respectively outputting the VGT and the EGR default openness to control the executers, or obtaining the VGT and the EGR closed ring control openness by taking the difference of the pressure target values and the practical measurement pressure values and the difference of the gas-feeding quantity target value and the practical measurement value of the gas-feeding quantity; comparing the prearranged open ring control openness with the VGT and the EGR closed ring control openness; and respectively controlling the two executers. In the invention, the closed ring control arithmetic and the open ring control arithmetic can be adopted selectively, therefore, the application working conditions of the system and the control effect of the system is improved.

Description

technical field [0001] The invention relates to a method and system for controlling an electronically controlled engine of an automobile, in particular to a method and system for controlling EGR and VGT of an engine. Background technique [0002] Conventional engines use naturally aspirated technology, where atmospheric pressure forces air directly into the combustion chamber without passing through any supercharger. The supercharging and intercooling technology invented later uses the compressor to compress the air, and then cools the compressed air through a heat exchanger (intercooler), so as to increase the intake air density, air intake volume and engine power of the engine. For the exhaust gas turbocharging used in a large number of vehicle engines, the turbine placed in the exhaust pipe is driven by the exhaust gas to rotate at a high speed. Since the drive shaft of the compressor is the same as the output shaft of the turbine, the turbine can drive the compressor to ...

AI Technical Summary

Problems solved by technology

This control strategy has the advantages of simplicity and good steady-state control effect, but because the PID algorithm cannot achieve good control effects in all working conditions, especially in some transient working conditions and special environments, its application effect is limited. limit

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