E．xcessive oil foaming in the crankcase of a refrigeration compressor is most likely to occur when the compressor

A．has run continuously for a long period

B．suction pressure is below normal

C．oil level is below normal

D．starts after a long idle period

[单选题]A diesel engines crankcase oil level is found to be too high√ You should suspect that （）.A . the engine was over filledB . there might be a fuel leakC . there might be a water leakD . all of the above

[单选题]Before pumping up the crankcase oil,（） should be worked by hand to minimize corrosive action on the liners.A . the indicatorsB . the starting valvesC . the cylinder lubricatorsD . the turning gear

[填空题] LOW OIL LEVEL COMPR CRANKCASE LSLL-731表示（）。

[单选题]The lube oil to lubricate the surfaces of the cylinder liners is spread over by the （）.A . sliding piston ringsB . engines camshaftC . small pumpsD . forced feed system

[单选题]To prevent excessive __ in the transverse girders, the tie bolts are positioned as close to the center of the crankshaft as possibleA．thermal stressesB．bending momentsC．thermal loadsD．surface tensions

[单选题]To prevent excessive __ in the transverse girders, the tie bolts are positioned as close to the center of the crankshaft as possibleA．thermal stressesB．bending momentsC．thermal loadsD．surface tensions

[单选题]Excessive vibration of an automatically fired auxiliary boiler can be caused by （）A . air or water in the furnaceB . combustion pulsesC . fuel oil pump failureD . flame failure

[单选题]Excessive alkalinity of the water in an auxiliary boiler can cause （）.A . caustic embrittlement of the boiler metalB . acidic corrosion of the boiler metalC . hard scale deposits on the boiler tubesD . etching of the heat exchange surface

[单选题]C．rankcase explosions in propulsion diesel engines result fromA．the splashing of lubrication oil by the crankshaftB．the dilution of crankcase oil with particles of combustionC．broken fuel lines spraying oil on the crankcaseD．the ignition of unburned

[单选题]C．rankcase explosions in propulsion diesel engines result from ____.A．the splashing of lubrication oil by the crankshaftB．the dilution of crankcase oil with particles of combustionC．broken fuel lines spraying oil on the crankcaseD．the ignition of unb