单项选择题
When fuel is injected in a diesel engine cylinder too early, （）
A.ignition may be delayed B.fuel economy is not affected C.exhaust gas temperature will be unchanged D.the exhaust will be clear
单项选择题 The purpose of an after-cooler is to（）
单项选择题 Early fuel injection timing is indicated by the cylinder pressure being（）
单项选择题 Critical speeds occurring within the operating speed range of a main propulsion diesel engine may be changed, or have their damaging effects reduced by a/an （）
