單項選擇題When fuel enters the crankcase of a diesel engine, it （）

A.dilutes the lube oil and reduces its viscosity
B.forms sulfuric acid in the lube oil
C.causes pitting and failure of the bearings
D.causes sludge deposits on valve stems


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1.單項選擇題In the construction of a diesel engine, what is the purpose of end plates?（）

A.To provide accessibility to the cylinder liners
B.To add stability to the engine block
C.To add rigidity to the block and a surface for attaching other parts
D.To make a surface for the base

2.單項選擇題A turbocharged, four-stroke/cycle diesel engine has a larger valve overlap than a naturally aspirated four-stroke/cycle diesel engine, in order to in crease the （）.

A.temperature of the exhaust gases
B.energy supplied to the turbocharger
C.air pressure to the intake manifold
D.purge of exhausted gases from the cylinders

3.單項選擇題A change in the quality of fuel atomization by a diesel engine fuel injector would be caused by a/an （）

A.increase in engine speed
B.increase in cylinder turbulence
C.leaking needle valve
D.reduction in cylinder turbulence

4.單項選擇題While maneuvering, you discover heavy smoke coming from the turbocharger casing, you should （）

A.check the air filter for dirt
B.check for an exhaust leak
C.check the cooling water temperature
D.notify the bridge that you are going to shut the engine down

5.單項選擇題Operating a diesel engine under light loads and at low temperatures for an exhaust for an extended period can result in（）

A.formation of carbon on the intake and exhaust ports
B.high water jacket temperatures
C.overheated pistons and cylinders
D.an increase in lube oil viscosity due to fuel dilution