1993年10月1日是执行欧洲一级标准规定的日期。也就是说,不久在欧洲将首次对碳黑微粒排放及固体和液体碳水微粒排放进行严格限制,同时对NO_x的排放限制到9.0g/(kW·h)。柴油机里燃料燃烤越充分,燃烧时间就越长,NO_x就越多,微粒也就越少。发动机制造厂家的麻烦在于,要降低NO_x的排放,就意味着产生更多的微粒,每千瓦小时燃料消耗就更多。奔驰公司的科研人员在不增加油耗、不 October 1, 1993 is the date of implementation of European standards. That is, for the first time in Europe it will be the first time that carbon black particulate emissions and solid and liquid carbon particulate emissions will be severely restricted while limiting NO x emissions to 9.0 g / (kW · h). Diesel fuel burn more fully, the longer burning time, the NO_x, the fewer particles. The trouble for the engine manufacturer is that reducing NOx emissions means generating more particles and more fuel per kilowatt-hour. Benz company’s researchers do not increase fuel consumption, no