NOx emission control method and device

Abstract

The invention provides a NOx emission control method and device. The current working condition information of an engine is obtained, the working condition information meets the low original emission switching condition, oil injection advance angle negative correction information of the engine is determined according to the working condition information, and the first oil injection advance angle of the engine is calculated; the fuel injection advance angle of the engine is adjusted based on the first fuel injection advance angle, and the engine is controlled to enter a low-original-emission operation mode so that the NOx emission of the engine can be reduced; if the working condition information does not meet the low original exhaust switching condition and meets the plateau exhaust switching condition, oil injection advance angle forward correction information of the engine is determined according to the working condition information, and a second oil injection advance angle of the engine is calculated; and adjusting the fuel injection advance angle based on the fuel injection advance angle forward correction coefficient scheduling, and controlling the engine to enter a plateau emission operation mode so as to increase the NOx emission of the engine. According to the invention, the NOx emission can be reduced, and the risk of urea crystallization and post-treatment crystallization blockage can be reduced.

Description

technical field [0001] The present application relates to the technical field of engines, and more specifically, to a NOx emission control method and device. Background technique [0002] Diesel engine after-treatment systems of China VI emission standards usually require selective catalytic reduction (Selective Catalytic Reduction, SCR) to inject urea to eliminate NOx emission pollutants. Too much will not only increase the cost, but also increase the risk of urea crystallization and reduce the conversion efficiency of SCR. [0003] In the prior art, since the fuel consumption of vehicles has a trade-off relationship with NOx emissions, the NOx emissions are usually increased in order to reduce fuel consumption, but after the NOx emissions increase, the injection amount of urea needs to be increased, and In winter, due to the low temperature, the risk of urea crystallization will increase, which will easily lead to after-treatment crystallization blockage and excessive NOx...

AI Technical Summary

Problems solved by technology

[0002] Diesel engine after-treatment systems of China VI emission standards usually require Selective Catalytic Reduction (SCR) to inject urea to eliminate NOx emission pollutants. Too much will not only increase the cost, but also increase the risk of urea crystallization and reduce the conversion efficiency of SCR

[0003] In the prior art, since the fuel consumption of the vehicle has a trade-off relationship with NOx emissions, the NOx emissions are usually increased in order to reduce the fuel consumption, but after the NOx emissions increase, it is necessary to increase the injection amount of urea, and In winter, due to the low temperature, the risk of urea crystallization will increase, which will easily lead to after-treatment crystallization blockage and excessive NOx emissions

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