单项选择题
Ring groove inserts are occasionally used on aluminum alloy piston to（）
A.reduce the ring groove wear rate
B.seal against crankcase vapors
C.lessen the wear on aluminum part of the cylinder
D.allow for the greater expansion rate of aluminum
相关考题
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单项选择题
A sudden drop in diesel engine cylinder compression pressure can be caused by（）
A.a leaking fuel injector nozzle
B.a clogged air filter
C.excessively early fuel injection
D.malfunctioning valves -
单项选择题
Which of the following statements is correct for the design and installation of diesel engine cooling water systems?（）
A.An alarm device with audible and visible signals is required for all cooling water systems
B.Propulsion engines with bores over 200 mm are to be fitted with cooling water jackets
C.Each totally enclosed cooling system shall be provided with a suitable head tank
D.Drain cocks are to be provided at the lowest points of all cylinder water jackets -
单项选择题
High exhaust back pressure will result in an increase in （）
A.turbocharger efficiency
B.engine power output
C.carbon deposits on fuel injectors
D.cylinder scavenging
