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1.前言社会上对保护环境和空气质量越来越重视。因此,许多国家规定了公路车辆汽油机废气中允许有害物质的极限值,对一氧化碳、氧化氮和碳氢化合物的含量实行了限制。因为柴油机废气中所含有害物质的浓度要比汽油机的低(图1),所以至今只有美国的加利福尼亚,根据13级试验规定了极限值。目前,在欧洲共同体范围内,对公路车辆有害物质的排放作出了法律上的规定。
1. Introduction There is a growing emphasis in the community on the protection of the environment and air quality. As a result, many countries have set limits on the amount of harmful substances that may be allowed in the exhaust of gasoline engines for road vehicles, limiting the levels of carbon monoxide, nitrogen oxides and hydrocarbons. Because diesel engine exhaust contains less harmful substances than gasoline engines (Figure 1), so far only California in the United States has set limits based on a Class 13 test. At present, within the European Community, the law sets out the emission of harmful substances on road vehicles.