单项选择题
A.seal the space between the piston and liner
B.transmit heat from the piston to the cylinder liner
C.reduce the amount of combustion gas blow-by
D.all of the above
单项选择题 What determines the number of events occurring in a cycle of operation in an internal combustion engine?（）
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 （）