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单选题
The burning of the fuel adds more heat to the air charge, causing it to expand and force the engine piston to do work on the crankshaftWhat does “it” mean in this sentence?（）
A
the burning
B
the fuel
C
the air charge
D
the engine piston
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更多 “单选题The burning of the fuel adds more heat to the air charge, causing it to expand and force the engine piston to do work on the crankshaftWhat does “it” mean in this sentence?（）A the burningB the fuelC the air chargeD the engine piston” 相关考题
考题
In the experiment, the burning inside the bottle can___.A. equalize the air pressure inside and outsideB. make a seal in the neck of the bottleC. finish up the oxygen inside the bottleD. produce more oxygen inside the bottle
考题
Passage ThreeHow can we get rid of garbage.9 Do we have enough energy sources to meet our future energy needs?These are two important questions that many people are asking today. Some people think that man might be able to solve both problems at the same time. They suggest using garbage as an energy source, and at the time it can save the land to hold garbage.For a long time, people buried garbage or dumped it on empty land. Now, empty land is scarce. But more and more garbage is produced each year. However, garbage can be a good fuel to use. The things in garbage do not look like coal, petroleum, or natural gas; but they are chemically similar to these fossil fuels. As we use up our fossil-fuel supplies, we might be able to use garbage as an energy source. Burning garbage is not a new idea. Some cities in Europe and the United States have been burning garbage for years. The heat that is produced by burning garbage is used to boil water. The steam that is produced is used to make electricity or to heat nearby buildings. In Paris, France, some power plants burn almost 2 million metric tons of the cities garbage each year. The amount of energy produced is about the same as would be produced by burning almost a half million barrels of oil.Our fossil fuel supplies are limited. Burning garbage might be one kind of energy source that we can use to help meet our energy needs.44. What two problems can man solve by burning garbage?A. The shortage of energy and air pollution.B. The shortage of energy and the land to hold garbage.C. Air pollution and the shortage of fossil fuel.D. Air pollution and the shortage of land to hold garbage.
考题
Air pollutionPeople and air pollution are often in the same places. This means that cities with large populations have the biggest problem of dirty air. Air pollution is caused by many different things. A major kind of air pollution is the gas from cars. Statistics(统计资料) show that 93 percent of all auto trips are within cities.Another major kind of dirty air is the burning of coal and oil for energy. This energy is needed to make electricity. Of course, much more electricity is used in the city than in the county.On the average, we throw away more rubbish than the year before. The burning of rubbish makes air pollution even worse. Many major industries are also responsible for the dirty air in the around cities. The fumes(烟)from iron, steel, chemical, and petrol production add particles(微粒)to the air.The effects of air pollution range from mild headaches to death. The levels of pollution found in heavy traffic may cause headaches for loss of clear vision. Wherever coal and oil are used for fuel, fumes may kill trees and plants and cause metal to corrode(腐蚀). In some of the larger cities, these fumes endanger the lives of human beings by contributing to lung diseases and causing early death.26. The key point of the passage is that().A. the cause of air pollution is peopleB. the causes and the effects of air pollution are both found in citiesC. the effects of air pollution range from headaches to death27. What is the purpose of this passage?A. to persuade people to stop polluting the air().B. to tell the causes of air pollutionC. to tell why cities are bad places to live28. Why is air pollution more grave in the city than in the country?().A. Because there are larger populations in cities.B. Because the air in the city is dirty.C. Because there are much more gas fumes from cars and burning of coal and oil for energy in the city than in the country.29. The fumes from coal and oil may cause metal().A. to corrodeB. to twistC. to turn black30. In larger cities, the fumes from coal and oil may contribute to().A. heart diseaseB. loss of clear visionC. lung diseases
考题
If the engine does not start on air, it may be due toA.low compression of the fuel pumpsB.incorrect timing of fuel pumpsC.the starting air valves stuckD.air-locks in fuel oil pipeline
考题
第一组： The Wartsila 50DF operates on the lean-bum principle: the mixture of air and gas in the cylinder has more air than is needed for complete combustion. Lean combustion reduces peak temperatures and therefore NOx emissions. Efficiency is increased and higher output is reached while avoiding knocking. Combustion of the lean air-fuel mixture is initiated by injecting a small amount of LFO (pilot fuel) into the cylinder. The pilot fuel is ignited in a conventional diesel process, providing a high-energy ignition source for the main engine. To obtain the best efficiency and lowest emissions, every cylinder is individually controlled to ensure operation at the correct air-fuel ratio and with the correct amount and timing of pilot fuel rejection. Wartsila has developed a special electronic control system to cope with the demanding task of controlling the combustion in each cylinder, and to ensure optimal performance in terms of efficiency and emissions under all conditions by keeping each cylinder within the operating window. Stable and well-controlled combustion also contributes to less mechanical and thermal load on the engine components. Current stringent emission regulations demand the reduction of NOx emissions. In an internal combustion engine this means controlling peak temperature and residence time, which are the main parameters governing NOx formations. In the Wartsila 50DF engine, the air-fuel ratio is very high (typically 2.2). Since the same specific heat quantity released by combustion is used to heat up a larger mass of air, the maximum temperature and consequently NOx formation are lower. The mixture is uniform. throughout the cylinder since the fuel and air are premixed before introduction into the cylinders, which helps to avoid local NOx formation points within the cylinder. Benefiting from this unique feature, NOx emissions from the Wartsila 50DF are extremely and comply with the most stringent existing legislation.What is the combustion feature of the Wartsila 50DF?A.Lean air in the cylinderB.Excessive fuel in the cylinderC.Excessive air in the cylinderD.Spark ignition
考题
Prior to burning or welding on a fuel tank on a ship，regulations require that an inspection be made. An entry in the unofficial logbook is required if this inspection is made by ______.A.a marine chemistB.the Officer in Charge，Marine InspectionC.the Master or person in charge of the shipD.the National Fire Protection Association
考题
The primary danger in helicopter fires is ______.A.burning jet fuel running on to quarters or other areasB.loss of stabilityC.rotating and flying debrisD.heat damage to helicopter structure
考题
Passage Four
How can we get rid of garbage?Do we have enough energy sources to meet our future energy needs?
These are two important questions that many people are asking today．Some people think that man might be able to solve both problems at the same time,They suggest using garbage as an energy source,and at the same time it can save the land to hold garbage．
For a long time,people buried garbage or dumped it on empty land．Now,empty land is scarce．But more and more garbage is produced each year．However,garbage can be a good fuel to use．The things in garbage do not look like coal,petroleum,or natural gas;but they are chemically similar to these fossil fuels．As we use up our fossil-fuel supplies,we might be able to use garbage as an energy source．Burning garbage is not a new idea．Some cities in Europe and the United States have been burning garbage for years．The heat that is produced by burning garbage is used to boil water．The steam that is produced is used to make electricity or to heat nearby,buildings．In Paris,France,some power plants burn almost 2 million metric tons of the cities garbage each year．The amount of energy produced is about the same as would be produced by burning almost a half million barrels of oil．
Our fossil fuel supplies are limited．Burning garbage might be one kind of energy source that we can use to help meet our energy needs．This method could also reduce the amount if garbage piling up on the earth．
The best title for the passage may be______A.Garbage and the Earth
B.Fossil Fuel and Garbage
C.Land and Garbage
D.Garbage?Energy Source
考题
Passage Four
How can we get rid of garbage?Do we have enough energy sources to meet our future energy needs?
These are two important questions that many people are asking today．Some people think that man might be able to solve both problems at the same time,They suggest using garbage as an energy source,and at the same time it can save the land to hold garbage．
For a long time,people buried garbage or dumped it on empty land．Now,empty land is scarce．But more and more garbage is produced each year．However,garbage can be a good fuel to use．The things in garbage do not look like coal,petroleum,or natural gas;but they are chemically similar to these fossil fuels．As we use up our fossil-fuel supplies,we might be able to use garbage as an energy source．Burning garbage is not a new idea．Some cities in Europe and the United States have been burning garbage for years．The heat that is produced by burning garbage is used to boil water．The steam that is produced is used to make electricity or to heat nearby,buildings．In Paris,France,some power plants burn almost 2 million metric tons of the cities garbage each year．The amount of energy produced is about the same as would be produced by burning almost a half million barrels of oil．
Our fossil fuel supplies are limited．Burning garbage might be one kind of energy source that we can use to help meet our energy needs．This method could also reduce the amount if garbage piling up on the earth．
According to the passage,using garbage is______A.for heating in France each year
B.a new way in a modern society
C.a good way to solve the problem of energy shortage
D.too expensive as an energy source
考题
Passage Four
How can we get rid of garbage?Do we have enough energy sources to meet our future energy needs?
These are two important questions that many people are asking today．Some people think that man might be able to solve both problems at the same time,They suggest using garbage as an energy source,and at the same time it can save the land to hold garbage．
For a long time,people buried garbage or dumped it on empty land．Now,empty land is scarce．But more and more garbage is produced each year．However,garbage can be a good fuel to use．The things in garbage do not look like coal,petroleum,or natural gas;but they are chemically similar to these fossil fuels．As we use up our fossil-fuel supplies,we might be able to use garbage as an energy source．Burning garbage is not a new idea．Some cities in Europe and the United States have been burning garbage for years．The heat that is produced by burning garbage is used to boil water．The steam that is produced is used to make electricity or to heat nearby,buildings．In Paris,France,some power plants burn almost 2 million metric tons of the cities garbage each year．The amount of energy produced is about the same as would be produced by burning almost a half million barrels of oil．
Our fossil fuel supplies are limited．Burning garbage might be one kind of energy source that we can use to help meet our energy needs．This method could also reduce the amount if garbage piling up on the earth．
What is the author's attitude?A.Delighte
B.Sad
C.Agree in
D.Disagree in
考题
Passage Four
How can we get rid of garbage?Do we have enough energy sources to meet our future energy needs?
These are two important questions that many people are asking today．Some people think that man might be able to solve both problems at the same time,They suggest using garbage as an energy source,and at the same time it can save the land to hold garbage．
For a long time,people buried garbage or dumped it on empty land．Now,empty land is scarce．But more and more garbage is produced each year．However,garbage can be a good fuel to use．The things in garbage do not look like coal,petroleum,or natural gas;but they are chemically similar to these fossil fuels．As we use up our fossil-fuel supplies,we might be able to use garbage as an energy source．Burning garbage is not a new idea．Some cities in Europe and the United States have been burning garbage for years．The heat that is produced by burning garbage is used to boil water．The steam that is produced is used to make electricity or to heat nearby,buildings．In Paris,France,some power plants burn almost 2 million metric tons of the cities garbage each year．The amount of energy produced is about the same as would be produced by burning almost a half million barrels of oil．
Our fossil fuel supplies are limited．Burning garbage might be one kind of energy source that we can use to help meet our energy needs．This method could also reduce the amount if garbage piling up on the earth．
What two problems can man solve by burning garbage?A.The shortage of energy and air pollutio
B.The shortage of energy and the land to hold garbag
C.Air pollution and the shortage of fossil fue
D.Air pollution and the shortage of land to hold garbag
考题
单选题In a diesel engine, offers the heat energy directly（）； works as working medium and changes the heat energy to mechanical energy（）A
the burning of the fuel； medium shaftB
fuel spray； fresh airC
fuel； fuel sprayD
the burning of the fuel； the burned gas mixture
考题
单选题The air supplied to a diesel engine is compressed to （） (1) provide heat for the ignition of the fuel (2) decrease injection delayA
(1) only is correctB
(2) only is correctC
both (1) and (2) are correctD
neither (1) or (2) are correct
考题
单选题The cylinder contains a great weight of air and is capable of burning a great quantity of fuel at（）.A
the beginning of the compression strokeB
the beginning of the suction strokeC
the end of the working strokeD
the end of the exhaust stroke
考题
单选题A diesel engine is supercharged in order to（）A
lower the no-load RPMsB
provide more air for combine with the fuelC
increase the no-load RPMsD
provide more fuel combine with the air
考题
单选题A diesel engine may fail to start due to （）A
low air charge temperatureB
high cranking speedC
excessive fuel dilution of lube oilD
high compression pressure
考题
单选题In an operating diesel engine, pre-ignition can be caused by （）A
excessively late fuel injectionB
oil in the air chargeC
water in the fuelD
injection continuing after the fuel charge is ignited
考题
单选题The burning of the fuel adds more heat to the air charge, causing it to expand and force the engine piston to do work on the crankshaftWhat does “it” mean in this sentence?（）A
the burningB
the fuelC
the air chargeD
the engine piston
考题
单选题The term diesel engine scavenging means（）A
delivering more air into the cylinder than it would normally receive during an ordinary charging processB
forcing the products of combustion out of the cylinder with the fresh air chargeC
collecting the air charge at the cleanerD
combustion and expansion of hot gas
考题
单选题Gas exchange, which is a basic part of the cycle of an internal combustion engine, is（）A
the supply of normal air and removal of compressed airB
the supply of fuel oil and combustion of the atomized oilC
the supply of fresh air and removal of exhaust gasesD
the supply of fresh air and removal of the extra heat
考题
单选题Increased air （） will raise scavenge efficiency and allow a greater mass of air to be compressed； more fuel may now be burned giving an increased power.A
specific volumeB
densityC
viscosityD
calorific value
考题
单选题The crankcases of many diesel engines are kept under a slight vacuum to （）A
improve fuel economyB
increase the air charge velocityC
reduce the risk of explosionD
all of the above
考题
单选题Early models of the flash-type evaporators used a separate shell-and-tube heat exchanger as the air ejector condenser.More recent models use a combined air ejector condenser with the（）A
distilling condenserB
salt water feed heaterC
distillate coolerD
flash chamber
考题
单选题（） the cylinder will contain a great weight of air and will be capable of burning a great quantity of fuel.A
At the beginning of the compression strokeB
At the beginning of the suction strokeC
At the end of the working strokeD
At the end of the exhaust stroke
考题
单选题Heat for igniting the fuel oil in the cylinder of a diesel engine is generated by the （）A
electronic ignition systemB
compression of air by the pistonC
friction in the fuel injectorD
fuel oil bearing system
考题
单选题The process of scavenging a two-stroke/cycle diesel engine serves to（）A
improve fuel flow volumeB
cool the exhaust valvesC
reduce the intake air charge densityD
increase the temperature of exhaust gases
考题
单选题Fuel injected into a diesel engines cylinder is ignited by （）.A
the heat compressed fuel/air mixture in the cylinderB
the fuel igniterC
the fuel injectorD
the fuel pump
考题
单选题How does the engine adjust itself to different formulas of fuel?A
By piping in more oxygen for ethanol.B
By sensing the amount of oxygen in a car’s exhaust.C
By burning in a less-than-optimal mode.D
By stopping and checking the fuel tank.
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