|
With the increase of gasoline engines and the application of unleaded gasoline widely, the pollution of aromatic hydrocarbons from gasoline engine, which are harmful to environment and organisms, is getting more and more serious. And benzenes and phenyl of aromatics are of concern due to their higher risk of causing carcinogen. Therefore, we need to do research on the exhaust emissions and the model of gasoline engine with three-way catalyst (TWC), and then control the pollutant emissions. But, at present, few researches on the aromatic hydrocarbons emission characteristics of gasoline engine with TWC has been carried out in our country, especially on benzene, toluene, p-xylene emission characteristics and modeling.In this paper, the test has been done with the HL495IQ gasoline engine manufactured by Yuci Shanxi Gasoline Engines Company Ltd. When the exhausts from the gasoline engine passing by TWC, the regulated and unregulated pollutants were collected pre-catalyst and post-catalyst. The unregulated pollutants were analyzed by Gas chromatography Analysis to get the benzene, toluene, p-xylene emissions.After comparing the regulated and unregulated pollutants under different situations, we can know about the benzene emission characteristics.(1) The gasoline engine test we designed and the regulated and unregulated pollutants collecting method with active carbon tube are good, simply, and effective.(2) From the he benzene emission characteristics, we conclude that when the engine is working at 2600rpm with the load of 75% and 100%, TWC induces the benzene formation.(3) A net benzene formation window, ranging fromλ-values of 0.83-0.95, and pre-catalyst exhaust gas temperatures of 600-730℃, was observed. Dealkylation reactions of aromatic hydrocarbons are assumed to be the major pathway leading to benzene. But, the disciplinarian between temperature,λand the benzene formation in the catalyst is not very obvious.In order to illuminate the mechanism of the benzene formation in TWC, in the paper, we use Monte Carlo Method to model the aromatic hydrocarbons emission characteristics from gasoline engine with TWC, and do some simulation study on the aromatic hydrocarbons oxidation and benzene formation. We use the fomers’test data to proof the model, and find that the simulation is according to our test result.
|