单项选择题
Diesel engine air start system check valves are opened by （）
A.an air start cam B.cylinder compression pressure C.starting air pressure D.valve springs
单项选择题 The cetane rating of diesel fuel is an indication of the （）
单项选择题 The condensers located in various stages of a flash evaporator are cooled by（）
单项选择题 Which of the diesel engine components listed increase air density and helps to improve engine operating efficiency?（）
