单选题“This increase in charge air density is accomplished on most modern diesel engine types by use of exhaust gas turbo-charging, in which a turbine wheel driven by exhaust from the engine is rigidly coupled to a centrifugal type air compressor” According

A dry-type spark arrestor removes sparks from a diesel engine exhaust by ____.

A.increasing the linear velocity of the exhaust gases

B.changing directions of exhaust gas flow

C.decreasing the temperature of the exhaust gases

D.accelerating the exhaust gas through a reduced size orifice

The high air velocity leaving the compressor of an exhaust gas turbocharger is converted to pressure in the_______.

A.inlet nozzle ring

B.turbine wheel blade

C.diffuser passages

D.inlet volute

What is the function of the after-coolers installed in the diesel engine air intake system?

A.Decrease the air density

B.Increase the exhaust temperature

C.Decrease the lube oil temperature

D.Increase the air density

The relative air pressure in the inlet manifold of a turbocharged diesel engine is usually______.

A.greater than the average exhaust manifold pressure

B.less than the average exhaust manifold pressure

C.greater at the turbine wheel than at the impeller

D.greater at reduced engine speed

The closing of the exhaust valves used on a modern, large, low-speed, main propulsion diesel engine may be directly provided by_______.

A.large conical springs

B.compressed air pressure

C.hydraulic pressure

D.exhaust gas pressure

Which of the following conditions could contribute to the cracking of a diesel engine cylinder head?

A.Leaking seal ring

B.Insufficient heat transfer from the exhaust valves

C.Blocked cooling water passages to the head

D.Excessive scavenging air provided to the engine

Exhaust gases are generally removed from the cylinders of a two-stroke/cycle diesel engine by

A.natural aspiration

B.masked intake valves

C.air ceils

D.scavenging air