单项选择题
The exhaust valve opens before bottom dead center in a four stroke engine to（） Ⅰ.allow for blow down Ⅱ.Reduce pumping losses
A.Ⅰ only B.Ⅱ only C.both Ⅰ and Ⅱ D.neither Ⅰ nor Ⅱ
Which of the turbo-charging systems listed operates wit...
单项选择题Which of the turbo-charging systems listed operates with the least average back pressure in the exhaust manifold?（）
A.Constant volume B.Constant pressure C.Pulse pressure D.Radial flow
Which of the following conditions indicates the dilutio...
单项选择题Which of the following conditions indicates the dilution of diesel engine lube oil by fuel oil?（）
A.Water discharging from the water outlet of the lube oil purifier B.Fuel oil discharging from the water outlet of the lube oil purifier C.Lube oil discharging from the water outlet of the lube oil purifier D.A change in the lube oil viscosity
If a single cylinder relief valve on a diesel engine li...
单项选择题If a single cylinder relief valve on a diesel engine lists frequently while the engine is running, the cause may be an （）
A.excessively late injection timing for each cylinder B.incorrectly adjusted intake valve timing C.incorrectly adjusted fuel injector D.incorrectly adjusted intake valve clearance
