单项选择题
Combustion knock can occur in the cylinders of a diesel engine under any condition permitting （）.
A.a shortened ignition delay period
B.a lean fuel/air mixture
C.excess fuel in the combustion chamber
D.rapid vaporization of injected fuel droplets
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相关考题
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单项选择题
Which of the following may cause that an engine doesnt turn on starting air?（）
A.too low starting air pressure
B.main starting valve closed
C.neither A nor B
D.A and B -
单项选择题
Poor combustion in a diesel engine can be caused by （）.
A.high compression pressure
B.low intake air temperature
C.low exhaust pressure
D.high scavenge air temperature -
单项选择题
A built-up exhaust valve is one in which （）.
A.the stem and heads are made of different material
B.low-alloy steel is used throughout
C.a replaceable valve disk is welded to the head
D.the self-centering action comes from motion of the valve stem in the guide
