Control method for realizing precontrol EGR system

Abstract

The invention relates to a control method for realizing a precontrol EGR system. According to collected variation rate signals of rotation speeds and loads of an engine, an adjustment amount of an opening degree of a precontrol EGR valve of next cycle is determined, and a pre-adjustment amount of the opening degree of the precontrol EGR valve is added based on an actual opening degree of the EGR valve, so a pre-opening degree of the EGR valve can be computed; and during the current signal sampling cycle, an ideal target opening degree of the EGR valve is determined by a controller according tothe rotation speeds, loads and various amendment signals of the engine; and then, the target opening degree is compared with the determined pre-control opening degree of the EGR valve, and a PID adjustment parameter is determined through MAP table checking based on an error between the two opening degrees and an error rate, whereas the EGR opening degree error is not adjusted through setting of the PID parameter based on multiple computations. The precontrol EGR system provided by the invention has the beneficial effects that a problem about slow transient responding of the system can be solved effectively; oscillation and excessive adjustment of the system are effectively reduced; and transient responding of the EGR system is improved.

Description

technical field [0001] The invention relates to an energy recycling technology, in particular to a control method for realizing pre-control exhaust gas recirculation system. Background technique [0002] EGR (Exhaust Gas Recycle) exhaust gas recirculation, that is, part of the exhaust gas in the engine exhaust pipe is introduced into the intake manifold through the EGR system, re-mixed with fresh air and then enters the cylinder, because the exhaust gas has a high specific heat and can reduce combustion Therefore, the introduction of EGR system can effectively reduce the emission of NOx in engine exhaust. However, if the actual EGR rate is not properly controlled, not only will the effect of reducing engine emissions not be achieved, but it will affect the power and fuel economy of the engine. Therefore, it is very important to accurately control the EGR rate. In response to this problem, most of the current markets use electronically controlled EGR systems to control the f...

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Problems solved by technology

[0005] The invention aims at the problem that the traditional PID control method tends to overshoot and oscillate during the process of adjusting the time-varying nonlinear EGR system, which makes the response of the EGR system slow and causes inaccurate control of the actual EGR rate. The control method of the pre-control exhaust gas recirculation system, through the change rate of the engine load and speed, combined with the adjustment of the sequence, completes the pre-control of the EGR valve opening of the engine in the next signal sampling period based on the current EGR valve opening; To control the error between the determined EGR valve opening and the ideal EGR valve opening corresponding to the engine operating condition in the next signal sampling period, a MAP look-up table PID control is adopted

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