单项选择题
A.Crankshaft revolution
B.Type of engine (diesel or gasoline)
C.Distance a piston travels during a stroke
D.Number of pistons
单项选择题 Which of the factors listed has the greatest effect on the mechanical efficiency of a diesel engine?（）
单项选择题 A practical way of checking for excessive fuel injection in one cylinder of an operating diesel engine is to （）
单项选择题 If the compression ratio is increased on any diesel engine, （）