The mechanical efficiency of an engine （） because losses occur in the form of friction.

[单选题]Mechanical lubricators for diesel engine cylinders are usually small reciprocating pumps which are （）.A . operated manually once an hourB . operated until the engine has startedC . placed into operation only at maximum loadD . adjustable to meet lubr

[单选题]The conclusion that mechanical efficiency is always （） 100 percent is correct.A . small thanB . more thanC . little thanD . less tha

[单选题]In a simple mechanical governor, the （）.A . centrifugal force rotates the ball-headB . flyweight centrifugal force is balanced by spring forceC . flyweight centrifugal force is balanced by hydraulic pressureD . speeder spring alone actuates the fuel

[单选题]The efficiency of turbocharge system is increased by fitting a charge air cooler （） the compressor.A . insideB . beforeC . afterD . against

[名词解释] 机械性损伤（mechanical injury）

[单选题]（） are commonly used in mechanical-hydraulic governor（调速器） to sense engine speeds.A . BulbsB . BulksC . FlyweightsD . Flywheel

[试题]Iwasimpressed_______theefficiencyoftheworkdoneinthecompanyA．)inB)aboutC)withD)for

[主观题]配置效率Allocative efficiency

[主观题]静态效率（Static efficiency）

[主观题]经济效率（Economic efficiency）