Method for accurately judging ammonia leakage phenomenon of diesel vehicle

Abstract

The invention discloses a method for accurately judging the ammonia leakage phenomenon of a diesel vehicle. The method for accurately judging the ammonia leakage phenomenon of the diesel vehicle comprises the following steps: 1, determining the ammonia leakage phenomenon of the diesel vehicle; the method comprises the steps that firstly, under the conditions that a whole vehicle runs normally, the road working condition is good and overspeed does not occur, a large accelerator opening degree is selected, the vehicle is accelerated to a certain speed, the circulating fuel injection quantity of an engine reaches 20 mg / hub or above, and at the moment, upstream NOx has an obvious ppm peak value; secondly, after the speed is increased to the maximum speed, an accelerator is immediately and thoroughly released, at the moment, no injection amount exists in an engine, and the ppm value of upstream NOx reaches about 0 within a certain time; thirdly, delay time T is calculated according to the fresh air inflow of the current working condition. Compared with the prior art, the method has the advantages that the operation is simple and convenient, the ammonia leakage phenomenon of the whole diesel vehicle can be accurately detected and judged through a simple positioning method, and then the development of the whole diesel engine at the national sixth stage can be promoted.

Description

technical field [0001] The invention relates to the technical field of ammonia leakage detection of diesel vehicles, in particular to a method for accurately judging the phenomenon of ammonia leakage in diesel vehicles. Background technique [0002] During the development stage of the National VI diesel engine vehicle, diesel vehicles generally adopt the SCR (Selective Catalytic Reduction Technology) route. In the post-processing, the work of SCR needs to inject urea to consume NOx in the exhaust gas. However, if the amount of urea injection is unreasonable, it will easily cause NH3 leaks, which in turn affects engine emissions. [0003] In the general SCR calibration test process, it is first necessary to perform engine bench calibration in the laboratory, then carry out the vehicle plain test, and finally carry out the vehicle test in three high (high temperature, plateau, and high cold) environments. [0004] In the bench test stage of the laboratory, due to the professi...

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Problems solved by technology

[0004] In the bench test stage of the laboratory, due to the professional measuring equipment, NH3 leakage can be easily measured. However, there is no mature method for detecting NH3 leakage on the whole vehicle, especially on batch production vehicles.