单项选择题
A.increase thermal efficiency
B.cause clogging of the fuel system
C.increase the ability of the engine to start in cold weather
D.produce corrosion in the cylinder and exhaust system at low loads
单项选择题 Leaking oil seals on a diesel engine turbocharger can cause（）
单项选择题 If the back clearance of a piston ring is excessive,（）
单项选择题 Corrosion and grooving on the blade of an exhaust driven turbocharger is caused by certain components of residual fuel oilsThese components are vanadium,sodium, and（）