D. cutting a square notch at each end of the crack
28. To anneal (退火)a copper gasket, you should heat the gasket _______.
A. and quench it in oil B. cherry red and quench in water
C. and let it cool slowly in the air D. and carbonize it
29. When a vessel is in dry-dock, the vessel's engineers should ______. A. examine the condition of the propeller B. chip and paint all hull protection zincs C. install new docking plugs in all cofferdams D. inspect the hull for hogging or sagging
30. We have stayed at Shanghai port for a long time. The fouling on the ship?s hull greatly increases her ______.
A. power B. speed C. resistance D. thrust force 31. Preventive maintenance _____.
A. should not be carried out during the watches B. can only be carried out in port
C. is a kind of maintenances carried out prior to the occurrence D. is a kind of maintenances carried out after the occurrence
Lesson 12
Marine Medium Speed Diesel Engine I
单项选择题：
1. Because the castings of smaller engines are not so big and heavy, _______ and cylinder block may be made in one piece. A. the column B. the jacket C. cylinder cover D. cylinder liner 2. Bridge gauge can be used to measure ________ of a diesel engine. A. diameters of journals B. deflections of crankwebs C. diameters of crankpins D. none of the above
3. Crankshafts of medium speed engines are _______ from a single piece of steel. A. unusually solid welded B. never be solid forged C. almost invariably solid forged D. almost invariably be welded
4. Doors are generally formed in the _______ of the both in-line and Vee engines to give maintenance access to the crankshaft main and connecting rod large end bearing. A. bedplates B. columns C. cylinder blocks D. safety caps 5. Each cylinder liner on the marine medium speed engines ________. A. is usually cooled by sea water B. can be replaced when worn out
C. is in direct contact with the water in the bore of the cylinder D. can?t expand when heated
6. For one or two types of engine, the piston and rod can be withdrawn downwards from the cylinder into the crankcase and then out through the _______. A. cylinder casing B. cylinder bore C. crankcase door D. aperture in the cylinder block
7. On the top of the cylinder is mounted the cylinder cover which is pressed onto ______ of the cylinder liner by means of nuts and studs. B 2 A. the camshaft B. the flange C. the ridge D. the bulge
8. Smaller engines can be made more rigid than large ones and may not have _______.
A. connecting rods B. crankshaft C. crankcase D. through bolts 9. The bore of each cylinder is formed in a liner which can be ________ when worn out.
A. welded B. replaced C. drilled again D. bored
10. The cap and new shell are tightened up and then removed and the thickness of the wire measured by ________. A. a bridge gauge B. a micrometer C. a thermometer D. an indicator 11. 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 liner B. wet liner C. dry liner D. drown liner
12. 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 walls B. divided walls C. dividing liners D. divided jackets
13. The crankshafts of medium speed engines are almost invariably solid _______ from a single piece of steel. A. forged B. cast C. made D. shrunk
14. The diameter of the crank pins should be measured with a ________. A. salinometer B. thermometer C. tachometer D. micrometer
15. The term medium speed diesel engine is currently taken to mean an engine with an operating rotational speed of _______ rpm. A. below 300 B. above 1200 C. between 300 to 1200 D. below 1200
16. When a crankshaft has to be handled outside the engine, it should be carefully supported in a manner which will ________ high bending moments on it. A. avoid imposing B. provide adequate C. avoid to impose D. provide with adequate
17. With the shell and cap assembled as for running, a check must be made that the clearance between the cap and the housing _______. A. has a nip B. is large enough C. is zero D. are suitable 18. For Vee-form engines, _______ is shaped to give two slopping surface on which _______ are placed at the correct relative angle to each other. A. the bottom of the column / the cylinder blocks B. the top of the column / the cylinder heads C. the top of the column / the cylinder blocks D. the bottom of the column / the cylinder heads
19. A distance piece, known as a ________ may be interposed between the rod and the bearing housing.
A. bearing shell B. bearing liner C. compression plate D. lead wire
20. A distance piece, with ground faces, known as a compression plate, may be interposed between the rod and the bearing housing, its thickness being chosen to ensure the correct _________ . A. compression pressure B. compression test C. compression ratio D. compression clearance 21. Adjust ________ by means of lead wire. A. the clearance of the main bearing B. the diameter of the main bearing C. the gap of the main bearing D. the tolerance of the main bearing
22. After ensuring that the _______ is correct the bearing clearance should be checked. A. nap B. gap C. nip D. deflection
23. Although the crankshafts of medium diesel engines appear to be robust, they rely on the support of ________ to develop their full strength. A. the piston rods B. the crank throws C. the thrust bearings D. the main bearings
24. __________ are generally formed in the frame of the both in-line and Vee engines to give maintenance access to the crankshaft main and connecting rod large end bearing. A. Doors B. Aspirate gauzer Coupling D. Blind
25. ________ are formed by abrasive particles entering the bearing and scoring the shaft.
A. Grooves B. Recesses C. Ridges D. Nips
26. A number of cylinder liners are enclosed in one cast iron casing to form a _______.
A. cylinder cover B. cylinder block C. cylinder frame D. bed plate
27. With the crank in position in the engine, some measurements can be taken by a special bridge gauge and _______.
A. a micrometer B. a bowel C. a feeler gauge D. a wrench
28. Vee-type engines have the connecting rods from two cylinders connected to each ______of the crankshaft.
A. throw B. web C. main bearing D. deflection
29. The bearing cap and shell are replaced and tightened up until ______. A. the “ nip “ is zero B. the “ nap “ is zero
C. the “ gap “ is correct D. the “ clearance “ is correct 30. The rotating range of the low speed diesel engine is usually lower than ______. A. 100 rpm B. 200 rpm C. 300 rpm D. 500 rpm
31. Excessive clearances in the main or crank-pin bearings will sometimes be indicated by ______ before any bearing knock is heard. A. loss of flow in the fuel system B. loss of pressure in the air system C. loss of flow in the lubricating system D. loss of pressure in the lubricating system
32. Medium speed engines have a ______power to weight ratio than the slow speed
two strokes, but due to the higher speeds tend to have ______maintenance intervals.
A. higher/reduced B. higher/increased C. lower/reduced D. lower/increased
33. A diesel engine which is rated for normal operation at a crankshaft speed of 800 RPM, is commonly classed as a ______.
A. slow-speed diesel B. medium-speed diesel C. high-speed diesel D. constant-speed diesel
Lesson 13
Marine Medium Speed Diesel Engine II
单项选择题：
1. As the plunger moves up, the ports are closed and the fuel ________ and delivered to the injector nozzle at very high pressure. A. being compressed B. to be pumped up C. is pressurized D. are built up 2. Piston may be made in _______ in order to keep the weight down for balancing purposes at high speed. A. cast iron B. forged steel C. stainless steel D. aluminum alloy 3. The _______ chamber is enclosed between the cylinder head and piston. A. lubrication B. injection C. cooling D. combustion
4. The bearing shell generally has ______ for location and oil grooves round the center of its axial length. A. tips B. tags C. lips D. keys
5. The bearing shells depend on the accuracy of ________ to held them in a true circular shape. A. the gap B. the clearance C. the bore D. the housing
6. The connecting rod large end bearing shell generally has tags for location and oil grooves round the center of its axial length which correspond with grooves in the ______ through which oil is transmitted up the rod to lubricate the small end. A. connecting rod B. piston rod C. bearing housing D. none of the above
7. The cooling of the piston is carried out by circulating _______ across the underside of the crown and inside the ring belt or through specially shaped passages. A. sea water B. scavenging air C. lubricating oil D. fuel oil
8. The correct tightening is obtained by use of _______ to measure the extension given to the bolts. A. pressure gauges B. stretch gauges C. thermometers D. bridge gauges
9. The crown is fairly thick with the cylindrical parts ________ to a thinner section. A. forged B. tapering C. drilling D. boring 10. The design of _______ is similar to that of the main bearing. A. the block bearing B. the camshaft bearing C. the connecting rod small end bearing D. the connecting rod large end
bearing
11. The external circumference of a pair of main bearing shells is slightly ________ that of the bore of the housing which receives them. What?s the meaning of “that” in the sentence above? A. less than B. lighter than C. larger than D. smaller than 12. The gudgeon pin is carried in ________ in the piston skirt. A. the bearing B. the crosshead C. bosses D. bridges
13. The main bearing shells are made of steel with a lining of bearing metal which may be white metal, copper-lead or aluminum-tin alloy. What?s the meaning of “which” in the sentence above? A. main bearing shellsB. main bearing C. steel D. bearing metal
14. The main bearing shells often have a thin _______ of lead or indium to provide a layer giving protection against corrosion. A. flange B. flash C. plate D. sheet
15. The pistons of high output engines are often made in two pieces _______ together to form precisely shaped cooling chambers. A. screwed B. bolted C. welded D. shrunk
16. The rim of the piston may contain cut-out portions to accommodate ________ when they open. A. the gases B. the air C. the valves D. the injectors
17. The two halves of connection rod large end bearing are held together by ______. A. bridges B. tap bolts C. jack bolts D. shims
18. When the follower is on the base circle of the cam with a normal shape, the pump plunger is at the _______ of its stroke. A. top B. nip C. bottom D. middle
19. A gudgeon pin in a trunk piston may be free to float and rotate, with ________ to limit axial movement.
A. split pins B crankpins C. dipsticks D. circlips
20. ________ is fully floating in both connecting rod small end and the piston skirt. A. The piston rod B. The cross head pin C. The gudgeon pin D. The crank-pin 21. In a diesel engine, an extremely leaking exhaust valve can cause ______.
A. misfiring B. pre-ignition C. interrupted scavenging D. reduced scavenging
22. A built-up exhaust valve is one in which ______. A. the stem and heads are made of different material B. low-alloy steel is used throughout
C. a replaceable valve disk is welded to the head
D. the self-centering action comes from motion of the valve stem in the guide 23. Fuel injection uses the jet pump system and a Woodward type hydraulic ______is used to control engine speed.
A. controller B. governor C. instrument D. apparatus
24. If fuel injection to a four-stroke/cycle diesel engine begins earlier than designed,