Evaluation and Correction Method of Diesel Engine Emission Cycle Test Results

Abstract

The invention provides a diesel engine emission circulation testing result evaluating and correcting method used for evaluating the treatment effect for diesel engine exhaust pollutants through an SCRcatalysis silencer. The evaluating method comprises the steps that the specific emission result of various pollutants is obtained, and the pollutant treatment effect is evaluated according to the specific emission result. The correcting method comprises the steps that firstly, the urea utilization rate of a catalyst adopted in the ith work condition point under different ammonia nitrogen ratios,different emission temperatures and different air speeds is obtained through sample or bench test calculation; secondly, according to the different ammonia nitrogen ratio, emission temperature and airspeed conditions during development and verification testing, the urea utilization rate and the correction coefficient at the ith work condition point during development and verification are obtainedaccording to the catalyst urea utilization rate; and thirdly, according to the correction coefficient, the NOx emission concentration of the ith work condition point after SCR posttreatment system treatment during verification testing is corrected. By means of the diesel engine emission circulation testing result evaluating and correcting method, the treatment effect on the diesel engine exhaustpollutants through the SCR catalysis silencer can be objectively evaluated.

Description

technical field [0001] The invention relates to the technical field of engine SCR post-processing, in particular to a method for evaluating and correcting diesel engine emission cycle test results. Background technique [0002] When carrying out bench verification of SCR injection system, packaging and other post-processing related assessment parts, it is often caused by different bench systems or different prototypes that the original NOx There are still differences between the concentration and the development status. These differences will directly affect the NOx emission results after the aftertreatment system, which is not conducive to making accurate judgments on the catalytic muffler, injection system and other related aftertreatment assessment parts. [0003] At present, there is no unified technical solution, and there are two common processing methods: one is to compare the NOx conversion efficiency of the two tests before and after the two test results, and then j...

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Problems solved by technology

[0007] The above two methods do not take into account the impact of the actual NOx conversion efficiency and urea utilization rate after the change of the ratio of ammonia gas to NOx gas (ammonia-nitrogen ratio) that actually participates in the reaction after the NOx change of the original machine, and cannot accurately and comprehensively evaluate the emission results. evaluation of

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