Exhaust Measuring And Experimental Study Of Benzene And Its Analogies From The Diesel Engine

The present study on engine emissions just stresses on the regulated pollutions (CO, NOx, HC and PM), quite few to the unregulated ones, especially on benzene and its analogies (benzene, toluene and xylene) emissions. Benzene, toluene and xylene in new houses, vehicles and in atmosphere are of special concern due to their carcinogenic impact. But in the atmospheric environment, most of the benzene and its analogies comes from the vehicle exhaust; therefore the emissions of benzene and its analogies from traffic exhaust should be worth to studying.The study covers an investigation of the trends of pollution levels of benzene, toluene and xylene from diesel engine. According to national emission standards, the sample system which simultaneously satisfies with the regulated pollutions and the benzene and its analogies emissions is established. Benzene and toluene are measured by gas chromatograph under optimizing operating conditions. External standards method is used for quantitative determination of benzene and toluene with Changchai ZS195. The experiments point out that the gas chromatography can be used as the qualitative and quantitative analysis method of the benzene and toluene, because it has the very high selectivity, the sensitivity and the repeatability. The same sample is also determined by Fourier transform infrared spectrometry(FTIS). It has good qualitative analysis function at present with good selectivity to benzene, toluene and xylene, but it is deficiency in quantitative analysis since the emission complex of diesel engine.The analysis results and characters of the two examination methods are discussed, as well as the primary factors that affect the veracity of the two methods. The examination results show that the pollution level of the benzene and its analogies emissions in turn is the toluene, benzene and xylene from high to low. Their exhaust values are concerned with the related parameters and operating mode of the diesel engine.An orthogonal test has been designed,which is 4 factors, including speed, load, fuel supply advance angle and the needle-value opening pressure, and different dimensions, and has been carried out.In order to get the basic rules of them from the diesel engine, the variance statistical analysis on the test result according to the orthogonal test table is done to obtain the remarkable factors that affect the exhaust emissions and determines the most superior working condition of them. The remarkable factors got consistent estimate both by the variance statistical analysis and test result.