单项选择题
A.a combination of constant volume and constant pressure
B.a combination of constant temperature and constant pressure
C.entirely constant pressure
D.entirely constant volume
单项选择题 The function of the piston compression rings used in a diesel engine is to （）
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?（）