一辆捷达柴油轿车,在运行过程中出现排气管向外严重冒黑烟的故障。柴油发动机工作时冒黑烟说明燃料燃烧不完全,分析其原因有以下几点:发动机超负荷工作;喷油泵供油量过多;供油时间太迟,使得燃料后燃期过长;气门间隙不对、气门粘滞或气门与气门座配合不好;空气滤清器漏气;排气背压过高;燃油品质太差;喷油器 A Jetta diesel sedan, the exhaust pipe in the course of serious black smoke out of the fault. Black smoke diesel engine work shows incomplete combustion of fuel, analysis of the reasons for the following: Engine overload; fuel injection pump too much fuel supply time is too late, making the fuel after the combustion period is too long; valve clearance Wrong, valve sticking or valve and valve seat with poor; air filter leaks; exhaust back pressure is too high; poor fuel quality; fuel injector