A . should be gradually increased
B . should be gradually reduced
C . should be constantly kept
D . should be varied up and dow
[单选题]In the closed cooling system, the water （）.A . is made to circulate out of the systemB . is made to circulate within the systemC . is made circulate within the systemD . is made circulate out of the system
[单选题]There is （） in any water cooling system for a diesel engine allowing for expansion and water make-up in the system as well as air vent and chemicals addition.A . a setting tankB . a service tankC . a head tankD . an expansion joint
[单选题]______ the temperature, ______ water turns into steam.A． The high... the fastB． Higher... fasterC． The more higher... the fasterD． The higher... the faster
[单选题]C．ooling water is circulated through______in some injectors.A．the nozzleB．the nozzle tipC．the internal passagesD．the fuel re-circulated
[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]The cooling water jacket is common to all the cylinders but there are often （） to ensure that each cylinder receives the right amount and flow of water.A . dividing wallsB . divided wallsC . dividing linersD . divided jacket
[单选题]The cooling water is in direct contact with the outer surface of the liner as a result of which it is termed a （）.A . water linerB . wet linerC . dry linerD . drown liner
[单选题]Fresh water is used for the cooling of cylinder jackets and （） of the marine diesel engine.A . cylinder coversB . lubricating spaceC . crossheadD . exhaust manifold
[单选题]The jacket water temperature in a diesel engine closed freshwater cooling system is normally controlled by （）A . regulating the level of corrosion inhibitor in the primary cooling systemB . the level of the freshwater expansion tankC . varying the en