国内外汽车发动机的技术现状及发展趋势外文文献翻译.doc

PAGE \* MERGEFORMAT PAGE \* MERGEFORMAT 1 Domestic and foreign automobile engine technology status and development trend ??????From the invention of the internal combustion engine development to one hundred years later, the relevant technical innovation and mature. However, the internal combustion engine as vehicle power still faces many problems, mainly thermal efficiency is not high enough (especially gasoline), relies diminishing oil resources, atmospheric pollution emissions, and difficulty concentrating governance. Therefore, the advanced engine technology in the automotive energy-saving, environmental protection, technological development plays a key decisive role. First, the diesel engines status and development trend 1.1 diesel engine performance characteristics 1) there is a high energy density (large low-speed supercharged diesel engine thermal efficiency over 50%), low fuel consumption, which saves energy and improve economic efficiency are important. 2) good fuel economy; 3) less greenhouse gas emissions, the CO2 emissions than its gasoline low around 30-35%, but the exhaust gases contain harmful ingredients (NO, particulate matter, etc.) are more noisy, environmental aspects in the environment has attracted attention. 4) a great range of power and speed (power 1-65580KW, speed 54-5000r/min), so wide application area. 5) structure is more complex, parts materials and processes are higher, higher manufacturing costs, higher quality compared with gasoline. There are three major advantages: ????a. economy. Firstly, the energy content of diesel fuel per unit than gasoline; secondly, a compression ignition engine characteristics, so that the thermal efficiency higher than gasoline. Average fuel consumption of diesel gasoline lower than 30% to 40%. ????b. environmental protection. In general, the main vehicle emissions of carbon monoxide, hydrocarbons, carbon dioxide, particulate matter and nitrogen oxides. In contrast, the engine of the carbon monoxide,