The pH value of water in a diesel engine closed cooling water system should be maintained between （）.

[单选题]The cooling water of the diesel engine should be treated with chemical, because it contains .A．alkaliB．acidityC．salinityD．impurity

[单选题]In a diesel engine cooling water system, a pH of 60 indicates a/an （）.A . slightly acidic conditionB . slightly alkaline conditionC . overtreatment of waterD . neutral condition of water

[单选题]A diesel engine cooling water system with a pH factor of 30 indicates a condition of （）.A . slight acidityB . slight alkalinityC . excessive alkalinityD . excessive acidity

[单选题]High diesel engine cooling water temperatures can be caused by （）.A . a worn water pumpB . not enough coolantC . air in the cooling systemD . all of the above

[单选题]Diesel engine jacket water is used in the distillation process as the （）.A . coolant for the distillateB . coolant for the brine coolerC . means of heating the feedwaterD . primary means of producing a vacuum within the distiller

[单选题]_____ the engines, the diesel engine is ____ used engine on boardA．Between / more commonlyB．Among / the most commonlyC．Between / not more commonlyD．Among / not the most commonly

[单选题]The heart of the diesel engine is the （） where the fuel is burnt and the power developed.A . crankcaseB . cylinderC . scavenge boxD . pisto

[单选题]The diesel engine is a type of （）.A . turbine engineB . gas turbineC . steam engineD . internal combustion engine

[单选题]D．iesel engine blow-by is the leakage of combustion gases past the( ).A．oil rings onlyB．compression and scraper ringsC．cylinder liner sealingD．cylinder liner ring grooves

[单选题]F．or a continuous operation diesel engine, a duplex filter unit would be the best arrangement becauseA．changing filter elements would not interrupt engine operationB．filtering occurs twice in each pass of oil through the systemC．clogging will not occ