The crankcase of many diesel engines are kept under a slight vacuum by the （）.

[单选题]A diesel engines crankcase oil level is found to be too high√ You should suspect that （）.A . the engine was over filledB . there might be a fuel leakC . there might be a water leakD . all of the above

[单选题]The crankcases of many diesel engines are kept under a slight vacuum to （）A . improve fuel economyB . increase the air charge velocityC . reduce the risk of explosionD . all of the above

[单选题]Regarding a Diesel engine crankcase, the general arrangement and installation should preclude the possibility of （）A . free entry of air to the crankcaseB . water entering the crankcase while engine wash-downs are being performedC . excessive oil lea

[单选题]_____ the engines, the diesel engine is ____ used engine on boardA．Between / more commonlyB．Among / the most commonlyC．Between / not more commonlyD．Among / not the most commonly

[单选题]A diesel engine crankcase ventilation system （）A . prevents spark generationB . removes combustible gasesC . determines the level of combustible gasesD . provides inert gas generation in crankcase

[单选题]D．iesel engines are started by supplying into the cylinders in the appropriate sequence for the required direction.A．cooling waterB．compressing airC．compressed airD．cylinder oil

[单选题]（） the engines, the diesel engine is（） used engine on board.A . Between；more commonlyB . Among；the most commonlyC . Between；not more commonlyD . Among；not the most commonly

[单选题]Diesel engines are started by supplying （） into the cylinders in the appropriate sequence for the required direction.A . cooling waterB . compressing airC . compressed airD . cylinder oil

[单选题]Lubricating systems for diesel engines are usually designed to initially provide lube oil to the engine （）A . camshaft beatingsB . main bearingsC . piston crownsD . cylinder wall

[单选题]In diesel engines designed with a crosshead, the motion of the piston rod can be described as （）.A . reciprocating at the piston pin, rotary at the crank pinB . reciprocating at the crank pin, rotary at the piston pinC . straight reciprocationD . str