单项选择题
The main operating characteristic of diesel engines which distinguishes them from other internal combustion engines is the （）
A.method of supplying air B.cooling system C.method of igniting fuel D.valve operating mechanism
单项选择题 Turbulence is created in the cylinders of a diesel engine to （）
单项选择题 The ratio of the brake horsepower to the indicate of a diesel engine is its （）
单项选择题 In order to keep excess oil from the intake ports in two-stroke/cycle diesel engines, （）
