Control method for high-pressure exhaust gas recirculation cooling bypass valve

Abstract

The invention provides a control method for a high-pressure exhaust gas recirculation cooling bypass valve. The control method comprises the following steps that a first opening and closing request value of the bypass valve is output according to the opening degree of an exhaust gas recirculation valve, a second opening and closing request value of the bypass valve is output according to recirculation exhaust gas flow, and a logical or operation value of the first opening and closing request value of the bypass valve, the second opening and closing request value of the bypass valve and an opening and closing value of an existing bypass valve is taken as an opening and closing output value of the bypass valve. According to the control method for the high-pressure exhaust gas recirculation cooling bypass valve, coking pollution of a gas inlet pipeline caused during small-flow exhaust gas recirculation and closing of the exhaust gas recirculation valve can be effectively avoided; icing ofthe gas inlet pipeline after an internal combustion engine is shut down in a low-temperature environment can be effectively reduced; the combustion stability of the internal combustion engine duringsmall-flow exhaust gas recirculation and closing of the exhaust gas recirculation valve can be effectively improved; and particle emission of the internal combustion engine during small-flow exhaust gas recirculation and closing of the exhaust gas recirculation valve can be effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of valve control, and in particular relates to a control method for a high-pressure waste gas recirculation cooling bypass valve. Background technique [0002] Exhaust gas recirculation (EGR) is used to reduce the emission of nitrogen oxides in the exhaust gas of internal combustion engines. When the exhaust gas temperature is high, it needs to be cooled down, the EGR exhaust gas flow rate is increased, and the mixed gas temperature is lowered. However, when the exhaust gas temperature is too low (such as lower than 110°C), cooling the recirculated exhaust gas will easily lead to unstable combustion and coking pollution of the intake pipe. Therefore, it is necessary to recirculate the exhaust gas for cooling bypass. [0003] The existing control strategies fail to fully consider two special working conditions. Working condition 1, when the exhaust gas recirculation flow rate is very small, after passing thr...

AI Technical Summary

Problems solved by technology

[0007] The purpose of the present invention is to provide a high-pressure exhaust gas recirculation cooling bypass valve control method, which aims to solve the problems of the existing exhaust gas recirculation flow rate is very small and the bypass valve is controlled to open and close when the exhaust gas recirculation valve is closed

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