Engine exhaust gas recirculation (EGR) valve closed-loop control system

Abstract

The invention relates to the field of engine exhaust gas recirculation rate control, in particular to an engine exhaust gas recirculation (EGR) valve closed-loop control system which comprises an EGR valve, a target EGR rate selection module, an actual EGR rate measurement module and a proportion integration differentiation (PID) controller. The target EGR rate selection module stores target EGR rates under different work conditions, the actual EGR rate measurement module can measure the actual EGR rate of an EGR valve under the current work condition, the actual EGR rate measurement module can send the actual EGR rate under the current work condition to the PID controller, and the target EGR rate selection module can send a target EGR rate corresponding to the current work condition to the PID controller. If the actual EGR rate and the target EGR rate are identical, the EGR valve remains valve core opening degree. If the actual EGR rate and the target EGR rate are different, the valve core opening degree of the EGR valve is adjusted so as to adjust the EGR rate. The system can monitor the EGR rate in real time, guarantees that the actual EGR rate and the target EGR rate are identical, enables an engine to be in the best condition and improves gasoline combustion performance.

Description

technical field [0001] The invention relates to the field of engine exhaust gas recirculation rate control, in particular to an engine EGR valve closed-loop control system. Background technique [0002] Exhaust Gas Recirculation (Exhaust Gas Recirculation) is a technology (method or method) in which a small internal combustion engine for automobiles separates a part of the exhaust gas after combustion, and introduces it into the intake side for recombustion. The main purpose is to reduce nitrogen oxides (NOx) in the exhaust gas and improve fuel consumption when sharing part of the load. Take the prefix "EGR" of each English word as the generic term. The EGR rate of the engine is the ratio between the mass flow through the EGR valve and the total air volume of the engine cylinder, so the spool opening of the EGR valve determines the EGR rate. [0003] After the engine on the vehicle is used for a long time, a large amount of impurities will be deposited on the hole wall of ...

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Problems solved by technology

[0003] After the engine on the vehicle has been used for a long time, a large amount of impurities will deposit on the hole wall of the EGR valve. The accumulation of impurities will inevitably lead to the reduction of the hole diameter, resulting in the actual amount of exhaust gas passing through the engine on the vehicle being less than ideal. In other words, the actual EGR rate is lower than the ideal EGR rate, which reduces the gasoline combustion performance and seriously affects the vehicle performance.

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