For an ordinary four-stroke diesel eng

1、Directional intake ports in diesel eng

Directional intake ports in diesel engines are used to （）.Areduce air charge turbulenceBinduce air swirlCdeflect hot combustion gas away from the valvesDoppose the effects of piston induced squish

2、For an ordinary four-stroke engine the

For an ordinary four-stroke engine the exhaust valves open （）.Aafter TDCBbefore TDCCafter BDCDbefore BDC

3、In a four-stroke cycle diesel engine t

In a four-stroke cycle diesel engine the intake valves open （）Abefore TDC and close after BDCBafter TDC and close after BDCCbefore TDC and close before BDCDafter TDC and close before BDC

4、For an ordinary modem marine four-stro

For an ordinary modem marine four-stroke engine the inlet valves close （）.Aafter TDCBbefore TDCCafter BDCDbefore BDC

5、Turbocharged four-stroke/cycle diesel

Turbocharged four-stroke/cycle diesel engines utilize valve overlap for（）.Aimproving cylinder scavengingBpreheating the combustion chamberCreducing air charge densityDpreventing valve wear

6、Marine four-stroke diesel engines are

Marine four-stroke diesel engines are mainly （）.Aof crosshead typeBof trunk piston typeCof low speed typeDall the above