Optimization cooperative control method for discharge of nitrogen oxides and particles of high-pressure common-rail diesel

Abstract

An optimization cooperative control method for discharge of nitrogen oxides and particles of a high-pressure common-rail diesel belongs to the technical field of diesel optimization control. A multi-input multi-output execution dependence heuristic dynamic-similar planning method is provided for optimization cooperative control of control variables such as rail pressure, EGR (exhaust gas recirculation) rate, oil jet quantity and oil jet timing which affect NOx (nitrogen oxides) and PM (particle matters) discharge of the high-pressure common-rail diesel. The method includes designing a utility function, designing an evaluation network, designing an execution network, offline study and online study. The problem of 'dimensionality disaster' in dynamic planning and control discharge of the diesel is solved, no mathematical model of a controlled object is needed during online application, and NOx and PM discharge can be synchronously optimized under all operating conditions. Further, potentials of purification in a cylinder of the high-pressure common-rail diesel are fully explored, load and requirements on a tail gas post-treating device are reduced, and accordingly the tail gas emission standard of the high-pressure common-rail diesel is raised with low cost.

Description

technical field [0001] The present invention relates to a method for optimizing and synergistically controlling nitrogen oxides and particle emissions of a high-pressure common-rail diesel engine, in particular to a high-pressure common-rail diesel engine nitrogen oxide (NO X ) and particulate (PM) emission optimization and synergistic control method. The invention belongs to the technical field of diesel engine optimal control. Background technique [0002] Analysis and test results show that the emission performance of high-pressure common rail diesel engine is mainly determined by four parameters, namely rail pressure, exhaust gas recirculation (EGR) rate, fuel injection quantity and fuel injection timing; the emission index that is difficult to control is nitrogen oxide ( NOx) and particulates (PM), because NO X It is often a contradictory relationship with the control of PM emissions: reducing NO X Emission measures often lead to an increase in PM emissions, and meas...

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Problems solved by technology

[0002] Analysis and test results show that the emission performance of high-pressure common rail diesel engine is mainly determined by four parameters, namely rail pressure, exhaust gas recirculation (EGR) rate, fuel injection quantity and fuel injection timing; the emission index that is difficult to control is nitrogen oxide ( NOx) and particulates (PM), because NO X It is often a contradictory relationship with the control of PM emissions: reducing NO X Emission measures often lead to an increase in PM emissions, and measures to reduce PM emissions often lead to NO X Increased emissions

[0003] In the past, people usually used the PID method to control the diesel engine, but the PID method can only be used in a single-input single-output system. For a nonlinear multiple-input multiple-output coupling system such as a diesel engine, it is often necessary to use multiple PID controllers. not effectively

In the existing technology, Kang from the University of Michigan and Kolmanovsky from the Ford Motor Company jointly adopted a dynamic programming method to control engine exhaust emissions. However, the dynamic programming method has the problem of "curse of dimensionality", and the amount of calculation is very large, so it is difficult to apply it to diesel engines. complex system of

Kheir from the University of Oakland in the United States and Salman from General Motors jointly used a fuzzy logic controller to optimize the fuel economy and exhaust emissions of the engine, but the fuzzy control method is still relatively rough, and it is difficult to optimize the fuel of the engine simultaneously under various operating conditions Economy and exhaust emissions

After searching the existing patents, it is found that the application number is: CN201010555816.2, and the invention patent titled: "Method and Implementation Device for Realizing Low Emissions of Heavy-duty Diesel Engines by Controlling Exhaust Temperature" proposes to use physical and chemical methods to control emissions, that is, adopt More expensive Selective Catalytic Reduction (SCR) units are more expensive to manufacture and operate

The application number is: CN201020613927.X, and the utility model patent titled "Passenger Car Engine Emission Control Device Based on In-Cylinder Fuel Dual Injection" uses a fuel dual injection device to control engine emissions, and its manufacturing and use costs are also relatively high

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