单项选择题
A.pressure B.temperature C.viscosity D.density
On engines having oil cooled pistons the lubricating oi...
单项选择题On engines having oil cooled pistons the lubricating oil pre-heater must be put into operation and the rate of heating so () that the temperature of the piston cooling oil returns are 32℃ to 35℃ over a period of at least two hours.
A.slow B.quick C.arranged D.high
Too much excess air is ()because the heat generated is ...
单项选择题Too much excess air is ()because the heat generated is being lost through the exhaust trunking instead of being made used of in heating the water to produce steam.
A.not good B.good C.better D.the best
() the oxygen content in the exhaust gas, () the combus...
单项选择题() the oxygen content in the exhaust gas, () the combustion is.
A.The lower;the worse B.The higher;the better C.The lower;the better D.The highest;the worst