| With the rapid development of the domestic economy,the vehicle ownership is escalating at present,and a large portion of the increment is devoted by private cars.With the increase of mileage and service life of vehicles,there will be a mass of carbon deposit in the intake valve of the port-fuel-injected gasoline engine which is widely used in the vehicles.The carbon deposit will cause many issues including power shortage,fuel consumption increasing and excessive emission.Consequently,in order to ensure the port-fuel-injected gasoline engine working in a good working conditions,the research of the generation mechanism of carbon deposit and prevent methods is imporant.Firstly,the research status of the engine carbon deposit and prevent methods had been investigated.Then a series of experiments including thermogravimetric analysis,infrared spectrometry,elemental analysis and scanning electron microscope are used to analysis the composition and morphology of the intake valve carbon deposit.To the composition of the carbon deposit,the relationships between the carbon deposit and other influence factors including gasoline,engine oil,soot particle and inorganic ash were analyzed.And the influence of the engine temperature on the intake valve carbon deposit was also discussed in the article.In the side of morphology,the effect of the different working conditions on the shape of deposit was studied in the thesis.Beside,according to the principle of port-fuel-injected gasoline engine,the generation mechanism of intake valve carbon deposit formation was analyzed theoretically.Finally,according to the generation mechanism of the carbon deposit formation,the prevent methods for carbon deposit were proposed including active prevent methods and inactive methods.The active methods include decreasing the idle time and using clean fuels,and the inactive methods include using of cleaning agent and mechanical shaving.All of the methods were verified in experiments. |
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