When direct injection diesel engines running from cold start or on low load, they will emitted a lot of blue smoke containing unburned hydrocarbons (HC) which are harmful to environment.

• 柴油机在冷起动和暖车以及低负荷运转时会排出大量含有未燃碳氢(HC)的蓝烟,给周围环境带来很大的危害。