A control system for self-adaptive correction of urea injection based on nox sensor

Abstract

The invention discloses a control system for self-adaptive correction of urea injection on the basis of a NOx sensor. The control system comprises an input signal module, the input signal module is connected with a NOx / NH3 rationality verification and calculation module, a correction coefficient adjustment module and a urea injection amount calculation module separately, the NOx / NH3 rationality verification and calculation module is connected with the correction coefficient adjustment module, the urea injection amount calculation module and an output signal module separately, the correction coefficient adjustment module is connected with the urea injection amount calculation module and the output signal module separately, and the urea injection amount calculation module is connected with the output signal module. Therefore, the urea injection amount can be precisely controlled according to the flow of NOx in a catalyst, and the robustness of an SCR closed-loop system can be enhanced.

Description

technical field [0001] The invention belongs to the technical field of engines, in particular to a control system for self-adaptive correction of urea injection based on a NOx sensor. Background technique [0002] Selective Catalytic Reduction (SCR) is currently the mainstream technology for diesel engine emissions. For diesel engines that use SCR post-treatment technology to meet National IV and National V emissions, the formulation of control strategies is based on MAP diagrams, that is, based on empirical values. . On heavy-duty diesel engines, the SCR open-loop control strategy can meet the National IV emission standards, but if you want to meet the National V and above emission standards, you must choose the SCR closed-loop control strategy. Currently commonly used closed-loop control strategies are: based on NOx sensors and based on NH 3 Closed-loop control strategy for sensors. [0003] The closed-loop control effect is subject to the linearization degree, accuracy...

AI Technical Summary

Problems solved by technology

If too much urea is injected, too much ammonia will volatilize into the environment, causing secondary pollution to the environment

If the amount of urea injection is too small, the catalytic conversion efficiency of NOx in the catalyst will be too low, and the emission of nitrogen oxides in the exhaust gas cannot be effectively reduced

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