Test method of universal characteristic of diesel engine

Abstract

The invention relates to a test method of a universal characteristic of a diesel engine. A particle trapping device matching a to-be-calibrated engine is selected and the particle trapping device with the particle trapping device tail dismounted is connected to an exhaust gas circuit; and then the following steps are implemented for a universal characteristic of an engine: the engine is started at a speed changing from a starting rotating speed to a highest rotating speed by using a rotating speed test step length as a step length, data of all working condition points are measured and then the engine is turned off; and the engine is started under a pressure changing from a starting average effective pressure to a largest pressure by using an average effective pressure step length as a step length, data of all working condition points are measured and then the engine is turned off. According to the test method provided by the invention, because the particle trapping device with the particle trapping device tail dismounted is applied to the universal characteristic test, no extra simulated testing device needs to be added and characteristics of the practical working condition can be simulated precisely, so that the calibration work efficiency of the engine can be improved substantially and the research and development cost can be lowered.

Description

technical field [0001] The invention relates to the field of vehicle engine calibration, in particular to an engine universal characteristic test method. Background technique [0002] Diesel engines are becoming more and more popular in vehicle engines because of their advantages such as high thermal efficiency and low fuel consumption. However, with the stricter emission regulations, some aftertreatment devices are also widely used in diesel engines. At present, the after-treatment device for solving the diesel engine emission problem includes a diesel engine exhaust particulate filter. Diesel particulate filter The diesel particulate filter can capture particulate matter in the exhaust through the internal filter device, but as the number of particulate matter collected in the diesel particulate filter increases, the exhaust back pressure also increases. During the diesel engine universal characteristics and original emission test, the basic test is generally completed b...

AI Technical Summary

Problems solved by technology

During the diesel engine universal characteristics and original emission test, the basic test is generally completed based on the back pressure of the fresh aftertreatment system. During the engine test, the exhaust particulate filter is used to capture the particles generated after combustion in the exhaust Meet the requirements of national emission regulations. When more and more particles are trapped in the particle filter, it will cause local blockage and poor exhaust. The data shows that the exhaust pressure increases, which will reduce the supercharging efficiency of the supercharger. , After supercharging, the pressure is too small and the intake air volume is too small, which makes the overall intake model of the engine inaccurate and cannot meet the test requirements, which brings great troubles to the basic calibration work;

[0003] In the existing calibration process, two methods are generally used to solve the clogging problem of the diesel particulate filter. Method 1: Once the exhaust pressure is found to be higher than the normal value during the test, the measure of forced engine post-injection is adopted to make the fuel enter the diesel engine quickly. When the exhaust pipe is burned, the temperature of the exhaust gas is raised to cause the particles to be burned and discharged; the advantage of this method is that no additional test equipment is required, and the disadvantage is that it takes a lot of time and fuel to remove the particles and this abnormal combustion will have a bad effect on the engine; Method 2: Use a valve-type pressure simulation device to replace the normal diesel particulate filter. The advantage of this method is that it avoids the problem of increased exhaust pressure due to particle clogging. The rotation speed and the exhaust pressure under the average effective pressure are close to the normal value, which wastes a lot of time and prolongs the development cycle

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