单项选择题
What is the purpose of the intake/exhaust valves in a diesel engine? （）
A.They regulate the combustion cycle B.They supply cooling water C.They synchronize the ignition spark D.They supply and regulate the lubricant flow
单项选择题 What is the operating principal of a flash type evaporator?（）
单项选择题 What is the effect of heated intake air on a diesel engine? （）
单项选择题 What is one effect of running a diesel engine at too cool a temperature? （）
