Pistons of marine medium speed diesel engines may be made of （） in order to keep the weight down for balancing purpose at high speed.

[单选题]On a medium-speed main propulsion diesel engine, the crank-pin or crank journal bearings receive lubricating oil from （）.A . a spindle lubricatorB . an oil jetC . internal splashingD . drilled passages in the crankshaft

[单选题]On a turbo-charged, medium-speed diesel engine, which of the following problems is an indication of a restricted air intake passage?（）A . Engine is hard to startB . Engine missesC . Surges at governed RPMD . Coolant temperature is too low

[单选题]Crankshafts of medium speed engines are （） from a single piece of steel.A . unusually solid weldedB . never be solid forgedC . almost invariably solid forgedD . almost invariably be welded

[单选题]E．ach cylinder liner on the marine medium speed engines _____.A．is usually cooled by sea waterB．can be replaced when worn outC．is in direct contact with the water in the bore of the cylinderD．can t expand when heated

[单选题]Each cylinder liner on the marine medium speed engines （）.A . is usually cooled by sea waterB . can be replaced when worn outC . is in direct contact with the water in the bore of the cylinderD . can t expand when heated

[单选题]Turbocharging of marine diesel engine is achieved by two distinct methods, （） termed the constant pressure and the pulse system.A . respectableB . respectfulC . respectiveD . respectively

[单选题]On a medium-speed main propulsion diesel engine, the crank-pin or crank journalbearings receive lubricating oil from( ).A．a spindle lubricatorB．an oil jetC．internal splashingD．drilled passages in the crankshaft

[单选题]The majority of medium speed and high speed marine diesel engines for main or auxiliary drive operate on the （） cycle.A . two-strokeB . four-stokeC . long-strokeD . short-stroke

[单选题]Before a marine diesel engine is started the cylinders and pistons must be （）.A . cooled to appropriate temperatureB . warmed up gradually to appropriate temperatureC . opened up and renewedD . ground and polished

[单选题]The marine diesel engine is a type of diesel engine used on ships The （） of its operation is not very difficult to understand.A . principleB . principalC . causeD . case