Marine four-stroke diesel engines are mainly （）.

[单选题]With four-stroke engines, it takes four revolutions of the crank shaft to make （） power stroke(s).A . 1B . 2C . 4D . 8

[单选题]In a four-stroke engines the camshaft rotates at （）.A . half the engine rotational speedB . twice the engine rotational speedC . the engine rotational speedD . four times the engine rotational speed

[单选题]For an ordinary modem marine four-stroke engine the inlet valves close （）.A . after TDCB . before TDCC . after BDCD . before BDC

[单选题]On a four-stroke diesel engine, when the piston is driven downwards by the expanding gas, it delivers power to the crankshaft through the （）.A . thrust blockB . sounding rodC . connecting rodD . push rod

[单选题]For an ordinary four-stroke diesel engine the exhaust valves close （）.A . after TDCB . before TDCC . after BDCD . before BDC

[单选题]Scavenging in a four-stroke/cycle diesel engine occurs during the （）.A . last part of the exhaust stroke, and the first part of the intake strokeB . last part of the intake stroke onlyC . early part of the injection stroke onlyD . early part of the p

[单选题]If a four-stroke/cycle diesel engine is running at 1550 RPM, the speed of the camshaft will be（）.A . 525 RPMB . 775 RPMC . 1550 RPMD . 1800 RPM

[单选题]In a four-stroke/cycle diesel engine, the camshaft rotates at （）A . twice the crankshaft speedB . half the crankshaft speedC . the same speed as that of the crankshaftD . a speed independent of that of the crankshaft

[单选题]Large marine diesel engines of crosshead construction generally have two systems of lubrication: a total loss system feeding the （） and a recirculation system lubricating the running gear and cooling the piston.A . cylinder liners and piston ringsB .

[单选题]In large marine diesel engines cylinder oils usually contain additives formulated to impart the （） to clean the rings and grooves.A . inefficiencyB . oilinessC . detergencyD . purity