SCR (Selective Catalytic Reduction) system of electrical control diesel engine and control method of SCR system

Abstract

The invention discloses a control method of an SCR (Selective Catalytic Reduction) system of an electrical control diesel engine. The control method comprises the following steps of: obtaining injection quantity of urea under the steady-state working condition by taking two-dimensional grids of rotation speed and torque and two-dimensional grids of exhaust temperature and air speed as base points and corresponding to NOX (Nitric Oxide) emission and NOX conversion efficiency of the original engine; and, based on an SCR steady-state control policy, correcting the injection quantity of the urea in the steady-state working condition by utilizing a correction model composed of an ammonia quantity storage function and adsorption and desorption functions of NH3, and obtaining the SCR control policy in the instantaneous-state working condition. Based on the model, the control method is nearly applied to all diesel engines; subsequent works of manufactures are only that corresponding calibration tests are carried out aiming at different types, therefore, the cost can be reduced, the research and development period can be shortened, and the research and development efficiency of the SCR system and a complete diesel engine factory can be greatly increased. The invention further discloses an SCR system of the electrical control diesel engine adopting the control method.

Description

technical field [0001] The invention relates to the technical field of engine emission treatment, in particular to a control method for an electronically controlled diesel engine SCR system. Background technique [0002] At present, energy shortage and environmental pollution are two major problems that plague the rapid development of the automobile industry. Therefore, the emission reduction technology used in automobiles has always been the target of widespread concern by the government and society. [0003] Since the mid-1970s, various internal purification technologies that mainly improve the combustion process of diesel engines have been rapidly developed and applied, especially the optimization and improvement of combustion methods, electronically controlled fuel injection, air intake supercharging and intercooling, The application of advanced technologies such as multi-valve has played a great role in reducing exhaust pollutants. [0004] However, with the implement...

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Problems solved by technology

[0008] Most of the existing SCR control strategies are formulated for each specific model. For different models, the control strategy may need to be greatly changed, which will make the strategy less scalable and lead to a longer development cycle. long, expensive

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