单项选择题
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
Which of the following may cause that an engine doesnt ...
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
Poor combustion in a diesel engine can be caused by （）....
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
A built-up exhaust valve is one in which （）.A.the stem ...
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
