汽油機燃料供給系 （Gasoline engine fuel supply system ）

1、汽油機燃料供給系 2（Gasoline engine fuel supply system 2）Gasoline engine fuel supply system 2.txt upwind direction, more suitable for flying. I am not afraid of all obstacles, but I am afraid I surrender. You lose 60 minutes of happiness when youre angry for a minute. Busy is a kind of happiness, so that we

2、do not have time to experience pain; running is a pleasure, let us truly feel life; fatigue is a kind of enjoyment, so that we have no time to empty. Life is like breathing, call is for a breath, suck is for a breath. The gasoline engine fuel supply system 2.txt33 to learn tolerance, means growth, s

3、how the wood can absorb more sun Fenghua, stretch strong and more mature power. Endurance is a significant hill dew clinging; a fear of wind defying rain perseverance; is not a title not mercenary loyalty. Untitled DocumentThe fourth chapter gasoline engine fuel supply systemFirst, the multiple-choi

4、ce question:Answer: 1.a, 2.d, 3.d, 4.a, 5.d, 6.b, 7.c, 8.b, 9.c, 10.a, 11.a, 12.b, 13.c, 14.d15.bTwo 、 judgment questions:Answer: 1.F, 2.F, 3.T, 4.T, 5.F, 6.T, 7.F, 8.F, 9.T, 10.F, 11.T, 12.T, 13.T, 14.F15.F, 16.F, 17.F, 18.F, 19.T, 20.T, 21.T, 22.F, 23.T, 24.F, 25.F, 26.F, 27.T28.T, 29.F, 30.F31.F,

5、 32.F, 33.F, 34.F, 35.T, 36.F, 38.T, 37.TThree. Questions and answers:What is the function of the fuel supply system of the 4-1. gasoline engine?Answer: gasoline engine fuel supply system function is according to the different working condition of the engine, with a certain quantity and concentratio

6、n of combustible gas mixture, and supplied to the cylinder in the near TDC on the spark ignition of complete power, the exhaust gas in the cylinder exhaust.What are the carburetor fuel supply systems for the 4-2. gasoline engine?A: the carburetor fuel supply system consists of four parts, the gasoli

7、ne supply device, the air supply device, the gas mixing device and the intake and exhaust device.What is the composition and function of the 4-3. float mechanism?A: the float mechanism consists of a float, a needle valve, and a float chamber. The function of the float chamber is to store the gasolin

8、e from the gasoline pump. The float and needle valve work together to maintain a suitable oil level in the float chamber.4-4. what is the function of the metering hole in the simple carburetor?Answer: control the amount of gasoline supplied.How does the 4-5. mixture form?A: when the engine is workin

9、g, the piston in the intake stroke runs from the TDC to the TDC. As the cylinder volume increases, there is a certain degree of vacuum, so that the air is sucked into the carburetor through the air filter. At the same time, in the float chamber and nozzle opening pressure difference, the float chamb

10、er in gasoline by volume ejected from the nozzle hole, and then by the high speed air flow away, the size of the particles become mist (fog). The atomized gasoline starts mixing with the air in the mixing chamber and enters the cylinder through the intake pipe and intake valve. From the gasoline to

11、the air, until it is burned, the gasoline continues to absorb heat, vaporize, and mix with the air.4-6: gasoline engine combustion process is how to carry out?A: when the gasoline engine is near the end of the compression stroke, the spark plug between the spark plugs located in the cylinder ignites

12、 the mixture immediately near the electrode to form a flame core. From then on, from the flame core, flames spread from side to side until the entire combustion chamber is swept, and most of the mixture is burned.4-7. what is excess air factor?Answer: the excess air factor is the ratio of the actual

13、 air quality to the air mass required for the complete combustion of the fuel in the combustion process.4-8. what is the air-fuel ratio?Answer: the air-fuel ratio is the ratio of air mass (kg) to fuel mass (kg) in the mixture.What is the effect of 4-9. mixture concentration on engine performance?Ans

14、wer: when the engine works, the theoretical mixture gas (alpha =1 or air-fuel ratio is 14.7:1) it is only theoretically possible to guarantee complete combustion. In fact, due to the limitation of time and space conditions, it is impossible for gasoline to mix with the air in a timely manner, and it

15、 is impossible to achieve complete combustion. Use alphaWhen the mixture of =1.05 to 1.15 is diluted, all gasoline molecules can be assured of sufficient air to achieve complete combustion, so that the engine is of the best economy. Using alpha =0.85 !Zero point nine fiveThe concentration of mixed g

16、as combustion, the fastest, the average working pressure of the cylinder top, can make the engine more power, the engine power is good, but due to the incomplete burning of fuel, the engine efficiency is poor. Gas mixture is too dilute (alpha)1.15) or mixed gas is too dense (alpha 0.88 =), because t

17、he amount of fuel in the mixture is too little or too much, will slow down the rate of combustion, leading to lower power and economy of the engine.When the mixture is dilute to alpha 1.3 to 1.4 or concentrated to alpha 0.4 to 0.5, it will not ignite and the engine will not work.4-10: what is the en

18、gine working condition? How to express?Answer: engine conditions are the abbreviation of their working conditions, usually expressed by engine speed and load.4-11: what is the engine load? How to express?Answer: the engine load refers to the engine external load, the engine output power varies with

19、the external load, and engine output power depends on the solar term door opening, so the opening load of the engine is available to represent the solar term door. The size of the load is generally expressed as a percentage, such as the throttle valve is fully closed, load0. Full throttle with load

20、of 100%.4-12: when the engine works, whats the requirement for the gas mixture concentration?Answer: in small load and medium load, it is necessary to supply the mixture which is thinner and thinner with the increase of load. When entering the heavy load until the full load condition, but also requi

21、res mixed gas as the load increases, from dilute to thicken, and finally concentrated to ensure that the engine to send the maximum power. In the starting, warming and accelerating transition conditions, the stronger mixing gas is required.4-13: what valves are there on the lid of the gasoline tank?

22、 What is its function?Answer: the gasoline tank lid is provided with an air valve and a steam valve. When the gasoline in the tank decreases, the pressure drops to a predetermined value (approx. 98kPa)When the air valve is opened, the air enters the tank to prevent the low pressure in the tank from

23、affecting the normal suction of the gasoline pump. When the ambient temperature is higher, the gasoline vapor in the tank is too high, and the pressure exceeds the predetermined value(110kPa) when the steam valve is pushed away, the gasoline vapor in the tank is discharged, thus preventing the press

24、ure in the tank from too high.What is the function of the 4-14. gasoline filter? How many kinds are there?Answer: the function of the gasoline filter is to filter the moisture and impurities in the gasoline to ensure the normal operation of the gasoline pump and carburetor. There are two types of ga

25、soline filters: detachable and integral.What is the function of the 4-15. gasoline pump?A: the function of the gasoline pump is to suck the gasoline out of the tank and pump the gasoline into the carburetors float chamber at a certain pressure through the line and the gasoline filter.Why is there a

26、vent in the lower part of the 4-16. gasoline pump?Answer: when the gasoline pump diaphragm is damaged, the gasoline is discharged from the oil drain hole so as not to leak the gasoline into crankcase contamination oil. In addition, the diaphragm pressure oil or oil under the arch, beneath the diaphr

27、agm air can enter or discharged from the oil drain hole in a timely manner, so as to avoid the diaphragm below the vacuum or air is compressed and increases resistance to motion. According to whether the oil drain hole out of the gasoline, it can also diagnose the failure of the gasoline pump diaphr

28、agm.How does the 4-17. gasoline pump adjust the fuel supply automatically?Answer: gasoline pump and carburetor float room work together, according to the work needs of the engine to achieve automatic adjustment of fuel supply. When the engine works, the actual amount of oil required gasoline pump, a

29、lways make the float chamber oil remain close to the specified height; the gasoline pump pressure in the process of oil, the oil surface float chamber to reach the required height so that the oil inlet valve is closed when the pump chamber is not completely out of gasoline, the diaphragm can not arc

30、hed upward to the highest position. The diaphragm down when the suction stroke while decreases, the amount of oil pump is reduced; the float chamber oil decreased when the float chamber oil inlet valve opening, the diaphragm arched upward pressure oil elevated position, when the suction stroke incre

31、ases, increase the amount of oil pump.Whats the function of the 4-18. air filter?Answer: the function of the air filter is to filter out impurities in the air to reduce engine wear. At the same time, the air filter can also reduce engine intake noise.What types of air filters are used in 4-19. at pr

32、esent? How does it filter out impurities in the air?Answer: at present the automobile engine widely uses the paper dry air filter.When the engine is in operation, the air inlet flows through the gap between the filter cover and the shell, and other small particles in the air are filtered out through

33、 the filter core.What are the advantages and disadvantages of the 4-20. paper dry air filter?Answer: dry paper air filter has the advantages of light weight, low cost, convenient use, high filtering efficiency of the filtering efficiency (up to 99.5%Above) advantages. The disadvantage is that the fi

34、lter is very sensitive to oil pollution. Once it is infiltrated by oil, it will lead to a sharp increase in intake resistance, which will affect the normal operation of the engine.What is the function of the main oil supply device of the 4-21. carburetor? How to achieve its function in structure?Ans

35、wer: the main oil supply device is to ensure that the engine in the small and medium-sized work around the work, to provide with the opening of the valve opening and gradually dilute the mixture.The main oil supply device usually adopts the method of reducing the vacuum at the main measuring hole to

36、 meet the requirement that the mixture becomes thinner when the opening of the valve increases. The vent pipe and air hole in the nozzle, so that a small amount of air infiltration to the main nozzle of the oil flow, and reduce the amount of pressure difference inside and outside the main hole, ther

37、eby reducing the flow velocity and flow rate of gasoline, the mixture with the throttle opening increases gradually thinning. The main fuel supply device can supply the required alpha in the middle and small load range as long as the proper sized main bore and the air measuring hole are selected=0.8

38、1.1s mixture. In addition, the air permeates the gasoline, makes the gasoline foam, foam gasoline is easier to be blown away by the air, atomization and evaporation.What is the function of the 4-22. idle device? How does it work?Answer: idle device is to ensure that the engine in idle and very small

39、 load conditions, the supply of less dense mixture. The working process of the idle device can be divided into the following four stages:(1) in low idle, solar term door opening the door in between the minimum solar term idle jet nozzle and the transition, the carburetor throat vacuum is very small,

40、 and the solar term under the door vacuum degree is large, only idle jet fuel, idling transition nozzle located above the door is the second solar term idle air hole, which not only can limit the idle jet out of fuel, and thus into the air also can make gasoline again bubble.(2When the door opened a

41、 solar term), the amount of air supply increases, the transition into the hole below the solar term door, and at the same time the ferry idle jet injection, the idle speed of the oil amount, mixed gas for instant thinning, in order to ensure smooth transition.(3When the opening of the throttle valve

42、 is further opened, the vacuum at the throat of the carburetor increases, and when the main oil supply device starts to work, the situation of three port injection is formed. At this point, the main nozzle oil quantity is less, and low gas velocity, the gas atomization is poor, only by working alone

43、 can not meet the requirements of load increase, the two oil supply device in a short period of time can work at the same time, due to the increase in the amount of air to prevent thinning caused by the transition of mixed gas.(4) when the throttle opening to enter the small increase engine load con

44、dition, idling jet hole and transition hole vacuum has been reduced to be sucked out of gasoline, the idle device stops working, and from the main supply device to work alone.What is the function of the 4-23. enrichment unit? Why are there two sets of condenser installed on the carburetor?Answer: Ca

45、rburetor plus device is used when the engine load increased to 80% to 85More than%, additional gasoline is supplied to ensure that the engine has the maximum power required for the stronger mixture.According to the structural principle, the time of the action of the mechanical concentration device i

46、s only related to the opening of the throttle valve, which is related to the load of the engine,It has nothing to do with engine speed. In actual use, before the mechanical enrichment device plays a role, because the mixed gas supply is the main supply device with the increase of load and thinning,

47、acceleration (solar term door opening will increase because of the mixed gas) thinning caused bad acceleration; in addition, a mechanical enrichment device plays a role after loading increase the speed of the engine falls, should also be further enriched gas mixture to increase the engine power, oth

48、erwise the engine flameout may have. A vacuum concentration device is added on the carburetor to overcome the shortcoming that the mechanical concentration device works at any time and has nothing to do with the rotating speed.What is the function of the 4-24. acceleration device?Answer: acceleratin

49、g device function when the vehicle is traveling to acceleration or overtaking, the door suddenly opened the instantaneous solar term will be a certain amount of fuel injected into a venturi, mixed gas which temporarily add thick, in order to meet the need for speed.What is the function of the 4-25.

50、starter? What is the usual starting device?Answer: the function of the starter is to provide a very strong mixture when the engine starts. The common starting device is the choke type.What types of 4-26. carburetor do you have?Answer: according to the throat of the airflow direction is different, ca

51、n be divided into modern carburetor suction, suction suction under the peace three; according to the number of different pipes, the modern carburetor can be divided into single pipe and multi venturi carburetor two; according to the number of the mixing chamber, the modern carburetor can be divided

52、into single cavity and multi cavity two.What are the main control mechanisms for the 4-27. carburetor? What is its function?Answer: carburetor control mechanism includes throttle control mechanism and choke control mechanism. The door control mechanism of general solar term foot control mechanism an

53、d hand control mechanism two, their function is: when the engine is working, opening by the drivers door to change the solar term gas supply, thereby changing the number of the engine, to achieve the purpose of changing the engine speed and the output power of the. The choke valve has only one hand

54、operated mechanism driven by a pull button and a wire rope. Its function is to control the opening of the choke.What is the function of the 4-28. intake and exhaust manifold?A: the function of the intake manifold is to distribute the mixture from the carburetor (gasoline engine) or the air from the

55、air filter (diesel engine) to the cylinders. The function of the exhaust manifold is thatWhat is the function of the 4-29. exhaust muffler?Answer: the function is to exhaust the exhaust energy, balance the pressure fluctuations of the air flow, thereby reducing exhaust noise, and eliminate the flame

56、 and Mars in the exhaust gas.How does the 4-30. check and adjust the height of the oil level in the float chamber?Answer: in use, if you find the engine in a variety of conditions, mixed gas too thick or too thin, check and adjust the carburetor float chamber oil surface height. The oil level of the

57、 float chamber can be observed at the oil window, and the oil level should be in line with the mark in the center of the observation window. The distance between the oil level and the plane on the body of the carburetor is approximately equal to that of the plane17mm.If the oil level does not meet t

58、he requirements, can be adjusted by the oil transfer mechanism of oil level adjusting screw. Adjust the engine to normal operating temperature and maintain idle operation.Turn the adjusting screws clockwise to lower the oil level of the float chamber. Turn the adjusting screws counterclockwise, and the oil level in the float chamber rises. After the adjustment is finished, after the engine has been working for a period of time, the oil face adjustment shall be checked for