System and method for cooperatively controlling supercharged diesel engine EGR valve, VGT and throttle valve

Abstract

The invention discloses a diesel engine air inlet and outlet control system. The diesel engine air inlet and outlet control system comprises an exhaust gas recirculation (EGR) valve, a variable geometry turbocharger (VGT) and a throttle valve to adjust the mass air flow (MAF) flowing into an engine. The engine control system comprises a first module and a second module, wherein the first module is a working condition state monitoring module based on position signals of an accelerator pedal and is used for judging whether the engine is in an urgent acceleration condition or not, the second module is used for adopting a transient open-loop control strategy under the urgent acceleration condition or an EGR valve, VGT and throttle valve cooperative control strategy with the difference of the MAF target value and the measured value as the control input according to the judgment result of the working condition of the first module, wherein the transient open-loop control strategy can improve the air inlet system reaction speed and optimize the transient smoke exhausting, and according to the EGR valve, VGT and throttle valve cooperative control strategy, the EGR valve is taken as the principal thing, VGT flow area adjusting is taken as the secondary thing, throttle valve control is taken as the auxiliary thing, and an MAF is accurately controlled. By means of the method, the complete opening state of the throttle valve can be kept as much as possible, the throttling loss can be reduced, and the purposes of improving the fuel economy and reducing standardized workloads are achieved.

Description

technical field [0001] The invention belongs to the technical field of intake and exhaust feedback control of diesel engines, and in particular relates to a system and method for cooperative control of an exhaust gas recirculation (EGR) valve, a variable geometry supercharger (VGT) and a throttle valve. Background technique [0002] The Exhaust Gas Recirculation (EGR) system can improve the operation of diesel engines and reduce NOx emissions. Supercharging technology can increase the intake air density, mass air flow (MAF) and power of diesel engines, and exhaust gas turbocharging is widely used in automotive diesel engines. In addition to effectively solving the problems of insufficient low-speed torque, poor part-load economy, and slow transient response that exist in the matching of ordinary turbochargers and diesel engines, VGT can also effectively solve the problem of exhaustion in some working conditions. To solve the problem of air pressure deficit, increase the rang...

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Problems solved by technology

[0003] The cooperation between EGR valve, VGT and throttle valve can solve this problem, but the three have cross-effects on MAF, backflow exhaust gas volume and boost pressure, and the coupling relationship is very complicated

The traditional single-input single-output strategy is very difficult to control MAF and return exhaust gas at the same time. As a result, most of the currently available VGT, EGR valve, and throttle joint controllers are highly complex systems that require extremely laborious calibration.

In addition, the optimal application of EGR and VGT technology under the rapid acceleration condition of a supercharged diesel engine is still a difficult problem

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