Feasibility study on the introduction of SEMS technology to motor vehicle emission testing

There is a big gap between the motor vehicle emission laboratory test and the actual road test, and the actual road test generally uses portable emission measurement system (PEMS) technology, but PEMS test has the disadvantages of complicated operation and heavy test equipment, and there is an urgent need for simple and easy actual road emission test technology. Smart Emission Measurement System (SEMS), based on sensor technology for motor vehicles emission test, has a simple system structure and convenient operation, and it is very necessary to introduce it into the actual driving emission testing of motor vehicles. There was a lack of SEMS technology testing and application research in China. By studying the current research status of SEMS technology, and carrying out comparative test experiments, the feasibility of introducing SEMS technology into motor vehicle emission testing and the problems were studied. The results showed that the difference between the particle number (PN) tested by SEMS and PEMS technologies was in the range of 10%-30%. The actual road comparison test results of nitrogen oxides (NO_x) emission had a large deviation, especially in the case of intense driving, and the maximum deviation was as high as 369%. The instantaneous distribution and cumulative distribution trends of PN and NO_x emission test results were relatively agreeable. Based on the test experiments and result analysis, the feasibility of introducing SEMS technology into vehicle emission testing was explored, which had certain feasibility and could be used for NO_x and PN high-emission vehicle screening.