轮机英语期末考试试卷A卷.docVIP

《轮机英语》A卷 姓名： 成绩： 单项选择题（每题2分共100分） The diesel engine is similar to the gasoline engine in that _______. Both of them are ignited by compressed air B. Both of them are the forms of external combustion engines C. Both of them have spark plugs D. The power is developed by the piston in the cylinder The ratio of th brake horsepower to the indicated by the ______. Thermal efficiency B. Mechanical efficiency C. Brake thermal efficiency D. Volumetric efficiency The ignition quality, of diesel fuel oil is indicated by the ______. Specific gravity B. Cetane number C. Viscosity D. Calorific value How are the pressure and temperature affected in a diesel engine cylinder during compression? Pressure and temperature decrease Pressure and temperature increase Pressure decreases and temperature increases Pressure increases and temperature decreases An aluminium piston has lower inertia and higher coefficient of ____compared to that of cast iron Viscosity B. Twisting moments C. Inertia D. Thermal expansion Each cylinder is closed at the top by a _____,made of a special heat-resistant steel. Cylinder liner B. Coupling flange C. Cylinder cover D. Piston The amount of fuel delivered by a helical plunger type fuel injection pump is controlled by_______. Rotation of the pump plunger B. Rotation of the pump barrel C. Varying the pump supply pressure D. Varying the pump return pressure In a diesel engine lube oil system, which of the following parts should be lubricated first? Camshaft bearing B. Main bearing C. Piston crowns D. Cylinder Sacrificial zinc anodes are used on he saltwater side of diesel engine heat exchangers to______. Reduce electrolytic action on heat exchanger metals B. Keep heat transfer surfaces shiny and clean C. Prevent rapid accumulation of marine growth D. Provide a protective coating on heat exchanger surfaces In a turbocharger, inlet air velocity is in creased in the _____. Inlet nozzle ring