Springs in fuel injectors will become not strong enough to work because______.A.the inject

Gear pumps are widely used to transfer any one of the following but .

A.fuel oil

B.lube oil

C.hydraulic oil

D.fresh water

viscosity ②cool the injector

A.①

B.②

C.①②

D.neither ① nor ②

What is the main problem lied in the ship recycling industry?

A.It lies in the sustainable development

B.It is about how to recycle the ship as they can as possible

C.It is a big problem concerning environment, safety and health

D.The big problem is that ship-recycling will violate the regulations made by IMO

hips"?

A.To withdraw a ship mid make it in a safe condition

B.To secure the life of a ship and recycle it

C.To break a wreck

D.To finish the service of a ship and break it without other problems

Which information is not given in the text?

A.Ship recycling contributes to sustainable development

B.The IMO believes that making an international instrument to regulate the ship recycling process is urgently in need

C.An international convention on ship recycling has been adopted

D.The IMO has taken action to develop an effective solution to the problem of ship recycling

第三组：

Ship recycling contributes to sustainable development and is the environmentally friendly way of disposing of ships with virtually every part of the hull, machinery, equipment, fittings and even furniture being re-used. However, while the principle of ship recycling is a sound one, the reported status of working practices and environmental standards in recycling facilities often leaves much to be desired. Such growing concerns about environmental safety, health and welfare matters in the ship recycling industry have resulted in a growing belief that an international instrument to regulate the ship recycling process is urgently needed.

Having become aware of the need to reduce the environmental, occupational health and safety risks related to ship recycling, as well as the need to secure the smooth withdrawal of ships that have reached the end of their operating lives, the International Maritime Organization (IMO) has taken action to develop a realistic and effective solution to the problem of ship recycling, which will take into account the particular characteristics of international maritime transport and the economic realities.

Which statement of the following is true?

A.Ship recycling is sustainable

B.Ship recycling is very friendly to our environment

C.Ship recycling is the best way to dispose the machinery, equipment, fittings and even furniture on board

D.Ship recycling brings many problems concerning environmental safety, health and______occupational safety

Which statement is NOT true?

A.While displacement pump works, volume of the working chamber will increase and decrease alternately

B.A gear pump always has two gears

C.Any vane pump will have a rotor within a ring

D.A balanced vane pump has two outlet ports and they are positioned symmetrically

Cooling water is circulated through______in some injectors.

A.the nozzle

B.the nozzle tip

C.the internal passages

D.the fuel re-circulated

第一组

Older loop scavenged engines may have a single injector mounted centrally in the cylinder head. Because the exhaust valve is in the center of the cylinder head on modern uniflow scavenged engines the fuel valves (2 or 3) are arranged around the periphery of the head. The pressure at which the injector operates can be adjusted by adjusting the loading on the spring. The pressures at which the injectors operate vary depending on the engine, but can be as high as 540 bar. Some injectors have internal cooling passages in them extending into the nozzle through which cooling water is circulated. This is to prevent overheating and burning of the nozzle tip. Injectors on modern engines do not have internal cooling passages. They are cooled by a combination of the intensive bore cooling in the cylinder head being close to the valve pockets and by the fuel which is re-circulated through the injector when the follower is on the base of the cam or when the engine is stopped. As well as cooling the injector, re-circulating the fuel when the engine is stopped keeps the fuel at the correct viscosity for injection by preventing it from cooling down. Fuel injectors must be kept in good condition to maintain optimum efficiency, and to prevent conditions arising which could lead to damage within the cylinder. Injectors should be changed in line with manufacturers&39; recommendations, overhauled and tested. Springs can weaken with repeated operation leading to the injector opening at a lower pressure than designed. The needle valve and seat can wear which together with worn nozzle holes will lead to incorrect atomization and dribbling.

Modern uniflow scavenged engines have______.

A.a single injector mounted in the center of the cylinder head

B.several injectors mounted around the external boundary of the cylinder head

C.a single injector mounted at the external boundary of the cylinder head

D.several injectors mounted in the center of the cylinder head

The fire drill must, as far as practicable, be conducted as if______.

A.there is a minor emergency

B.there is an actual emergency

C.there were a minor emergency

D.there were an actual emergency