Decoupling control method based on composite disturbance-rejection diesel engine VGT-EGR system

Abstract

The invention discloses a decoupling control method based on a composite disturbance-rejection diesel engine VGT-EGR system. The method mainly comprises the steps of static feedforward control, dynamic feedforward control and active disturbance-rejection control (ADRC). According to the VGT-EGR system, a two-input two-output system is converted into two single-input single-output channels; the coupling influence between the two channels, changes of dynamic characteristics of each channel along with changes of the working condition of an engine, and disturbance of the external environment are totally regarded as the total disturbance. The ADRC is used for performing real-time observation and compensation on the total disturbance, and precise modeling is not needed; however, the bandwidth of the ADRC is limited by the sampling frequency and noise, and transient tracking is slow. Therefore, the static feedforward control is added into the method, and the simple and efficient dynamic feedforward control based on a model is specially designed. A simulation result and an experimental verification result show that control parameters of the method are easy to calibrate, and rapid tracking of the boost pressure and the air input in the whole working condition can be achieved only through one set of parameters.

Description

technical field [0001] The invention relates to the control of the air system of diesel engines, especially designed for diesel engines equipped with variable geometry turbine (VGT) and external exhaust gas recirculation (EGR) systems, decoupling control of boost pressure and fresh air intake. Background technique [0002] The air system of a diesel engine is an important link to control the composition of intake air (mainly including fresh air and recirculated exhaust gas), intake pressure and temperature, and plays a vital role in improving the combustion process of diesel engines and reducing fuel consumption and emissions. With the increasingly stringent requirements of emission regulations, the structure of the air system is becoming more and more complex, and the requirements for control accuracy and response speed are also increasing, which makes the control of the air system face more and more challenges. There are various hardware configuration schemes for the air s...

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Problems solved by technology

Among them, robust control (X.Wei and L.del Re. "Gain scheduled H-infinity control for air path systems of diesel engines using LPV techniques". IEEE Trans.Control Syst.Technol, vol.15, no.3, pp.406–415, May 2007.) has been adopted by researchers, however, in order to reduce the sensitivity to model accuracy, the design of robust control is usually conservative, at the expense of response speed

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