Calibration method of engine SCR post processor

Abstract

The invention relates to a calibration method of an engine SCR post processor. The calibration method comprises the following steps of collecting working condition data in an engine rack to obtain gasparameter data and temperature parameter data; inputting the obtained temperature parameter data into an SCR temperature model for calculation, and obtaining the temperatures of an SCR carrier at different positions in the gas flow direction and the SCR downstream temperature; sequentially inputting the obtained gas parameter data, the obtained temperatures of the SCR carrier at the different positions in the gas flow direction and the SCR downstream temperature into an SCR kinetic parameter model and an SCR downstream gas content and SCR ammonia leakage calculation model for calculation to obtain the composition of each gas component at the SCR downstream; judging the obtained temperature and concentration and actually measured temperature and gas concentration; and finishing calibrationif both the temperature and component judgment results meet preset values. By means of the calibration method, the SCR calibration efficiency can be greatly improved, the rack and whole vehicle testtime is shortened, the development cost is saved, and the product research and development efficiency is improved.

Description

technical field [0001] The invention relates to the field of engine calibration, in particular to a calibration method for an engine SCR post-processor. Background technique [0002] At present, with the upgrading of diesel vehicle emission regulations, the National VI regulations NO x The requirements are more stringent. From the downstream NO of the national five ETC cycle (transient cycle: European transient cycle) x The limit value is 2.0g / kW·h, to the downstream NO of the National VI WHTC cycle (transient cycle: World harmonized transient cycle) x Limit 0.46g / kW·h, NO x While the limit value is lowered, the requirements for cycle conditions are also more stringent. Currently, diesel NO x There are two typical technical routes to meet China VI emission regulations: 1. EGR (Exhaust gas recirculation) route; 2. High-efficiency SCR route without EGR. Both technical routes require higher NO in SCR x Conversion efficiency, especially the high-efficiency SCR technology ...

AI Technical Summary

Problems solved by technology

[0006] Disadvantages of the existing technology: the traditional calibration method is based on the bench test, and it is necessary to repeatedly adjust the chemical kinetic calibration parameters through universal characteristic sweep point calibration, WHTC and WHSC verification

The calibration process takes a long period of time and high cost, and requires high professional requirements for calibration personnel

Existing simulation models can only consider limited test inputs, cannot cover the entire universal characteristics of the engine, and have the disadvantage of large simulation errors

In addition, many simulation models are based on the known ammonia-nitrogen ratio to reversely calculate the urea injection amount, and do not have the ability to calculate the urea injection amount forward

In addition, in different models, when the SCR temperature and the upstream input boundary of the SCR change, the bench calibration work needs to be performed again. The process is cumbersome, the calibration cycle is further extended, and the calibration cost is high.

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