2010级下学期期末试卷

2010级下学期期末试卷A卷

1.______ scavenge means both exhaust ports and scavenge ports are arranged to the same side.

A. Uniflow

B. Cross

C. Loop

D. Straight

2. An increase in load on a diesel engine results in _____ of speed of the crankshaft.

A. a reduction

B. an increase

C. an outing

D. a downwards

3. For an ordinary four-stroke engine the exhaust valves open _____.

A. after TDC

B. before TDC

C. after BDC

D. before BDC

4. A piston in a four-stroke/cycle diesel engine makes four strokes during each _____.

A. crankshaft revolution

B. mechanical cycle of operation

C. period of two combustion cycles

D. cycle of two events

5. The highest pressure in a diesel engine cylinder normally occurs _____.

A. at TDC

B. before TDC

C. after TDC

D. during air starting

6. A-frames are mounted on the bed plate and support ____ and cylinder blocks.

A. the main bearing

B. the cylinder cover

C. the entablature

D. the sump

7. In each cylinder cover there are two or three holes for _____.

A. the exhaust valves

B. the fuel valves

C. indicator cocks

D. the fuel pumps

8. The joint face between the cylinder cover and the liner is arranged _____ the combustion process as possible

A. such far away from

B. such near by

C. as far away from

D. as near by

9. Which of the diesel engine cylinder liners listed has internal cooling water passages?

A. Internally finned liner

B. Externally finned liner

C. Wet liner

D. Integral water-jacket liner

10. In order to improve the working conditions of the crosshead bearings, the bearing pressure is made _____and the peripheral

speed is made _____ in later designs.

A. smaller, higher

B. higher, smaller

C. smaller, smaller

D. higher, higher

11. ______or air venting arrangement is fitted to the fuel supply passage.

A. An air pump

B. A compressor

C. A fuel pump

D. A priming

12. If there is water in fuel oil , the revolution of the engine will ____.

A. decrease

B. increase

C. be dismantled

D. be reassembled

13. During the fuel injection period, fuel pressure must exceed cylinder gas pressure to _____.

A. ensure penetration and distribution of the fuel in the combustion chamber

B. ensure the needle valve is flushed clean during each injection

C. prevent combustion gas blowback into the open needle valve

D. prevent reflected pressure waves when the needle valve closes

14. Maintaining the proper fuel oil temperature will result in ______.

A. the elimination of valve wear

B. improved atomization

C. a decrease in cylinder blow-by

D. an increase in cylinder blow-by

15. When the heavy fuel oil is heated to achieve the viscosity of 10-15 cSt, _____ may occur. To avoid this,

a _____ system is used in most occasions.

A. boiling and cavitations; low temperature

B. boiling and cavitations; pressurized

C. leaking and boiling; low temperature

D. leaking and boiling; pressurized

16. The space between cylinder liner and jacket is called _____.