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Pic. 9. Carburetor operation 2107-1107010-20.
1. Accelerator pump lever; 2. Screw for adjusting the fuel supply of the accelerator pump; 3. Check valve plug of the accelerator pump; 4. Float chamber; 5. Fuel jet of the transition system of the second chamber; 6. Economizer air jet (econostat); 7. Air jet transition system; 8. Economizer fuel jet; 9. Main air jet of the second chamber; 10. Economizer emulsion jet; 11. Economizer atomizer; 12. Atomizer of the main dosing system of the second chamber; 13. Small diffuser of the second chamber; 14. Accelerator pump spray valve; 15. Accelerator pump atomizer; 16. Small diffuser of the first chamber; 17. Air damper; 18. Connecting sleeve of the carburetor channels; 19. The main air jet of the first chamber; 20. Air jet launcher; 21. Rod connecting the lever of the air damper axis with the rail of the starting device; 22. Case of the starting device; 23. Launcher rail; 24. Diaphragm of the starting device; 25. Trigger adjustment screw; 26. Air jet of the idle system; 27. Needle valve seat; 28. Needle valve; 29. Fuel filter; 30. Float bracket with stop and tongue; 31. Needle damper ball; 32. Float; 33. Fuel jet of the idle system; 34. The main fuel jet of the first chamber; 35. Emulsion tube of the first chamber; 36. Composition adjusting screw (quality) idle mixtures; 37. Adjusting screw for the amount of idle mixture; 38. Saddle of the adjusting screw; 39. Throttle valve of the first chamber; 40. First mixing chamber; 41. Second mixing chamber; 42. Throttle valve of the second chamber; 43. Fixed openings of the transition system; 44. Emulsion tube of the second chamber; 45. The main fuel jet of the second chamber; 46. Check valve accelerator pump; 47. Bypass jet of the accelerator pump; 48. Accelerator pump diaphragm; 49. Pneumatic jet located in the second chamber; 50. Pneumatic jet located in the first chamber; I. Scheme of carburetor operation at maximum engine power; II. Scheme of operation of the pneumatic actuator of the throttle valve of the second chamber; III. Scheme of the accelerator pump; IV. Scheme of operation of the starting device; V. Diagram of carburetor operation in throttling modes; VI. Scheme of the carburetor at idle.
1. Accelerator pump lever; 2. Screw for adjusting the fuel supply of the accelerator pump; 3. Check valve plug of the accelerator pump; 4. Float chamber; 5. Fuel jet of the transition system of the second chamber; 6. Economizer air jet (econostat); 7. Air jet transition system; 8. Economizer fuel jet; 9. Main air jet of the second chamber; 10. Economizer emulsion jet; 11. Economizer atomizer; 12. Atomizer of the main dosing system of the second chamber; 13. Small diffuser of the second chamber; 14. Accelerator pump spray valve; 15. Accelerator pump atomizer; 16. Small diffuser of the first chamber; 17. Air damper; 18. Connecting sleeve of the carburetor channels; 19. The main air jet of the first chamber; 20. Air jet launcher; 21. Rod connecting the lever of the air damper axis with the rail of the starting device; 22. Case of the starting device; 23. Launcher rail; 24. Diaphragm of the starting device; 25. Trigger adjustment screw; 26. Air jet of the idle system; 27. Needle valve seat; 28. Needle valve; 29. Fuel filter; 30. Float bracket with stop and tongue; 31. Needle damper ball; 32. Float; 33. Fuel jet of the idle system; 34. The main fuel jet of the first chamber; 35. Emulsion tube of the first chamber; 36. Composition adjusting screw (quality) idle mixtures; 37. Adjusting screw for the amount of idle mixture; 38. Saddle of the adjusting screw; 39. Throttle valve of the first chamber; 40. First mixing chamber; 41. Second mixing chamber; 42. Throttle valve of the second chamber; 43. Fixed openings of the transition system; 44. Emulsion tube of the second chamber; 45. The main fuel jet of the second chamber; 46. Check valve accelerator pump; 47. Bypass jet of the accelerator pump; 48. Accelerator pump diaphragm; 49. Pneumatic jet located in the second chamber; 50. Pneumatic jet located in the first chamber; I. Scheme of carburetor operation at maximum engine power; II. Scheme of operation of the pneumatic actuator of the throttle valve of the second chamber; III. Scheme of the accelerator pump; IV. Scheme of operation of the starting device; V. Diagram of carburetor operation in throttling modes; VI. Scheme of the carburetor at idle.
Starting a cold engine
When starting a cold engine, close the air damper 17 by pulling the control handle towards you until it stops. In this case, the rod 21 will take the leftmost position in the slot of the rail 23, and the rod 44 (see fig. 8), going down, under the action of turning the three-arm lever 38, it will turn the lever 46 and slightly open the throttle valve of the first chamber by the required amount. In this case, the resulting vacuum is transmitted both to the holes of the autonomous idle system, and through the ajar throttle valve 39 (see fig. 9) from the first chamber to the sprayer of the main dosing system.
Under the action of rarefaction, the fuel begins to intensively flow out of the holes of the idle system and the atomizer. From the openings of the idle system, the fuel enters in the form of an air-fuel emulsion. Air is mixed with the fuel through the air jet 26. Simultaneously, through the communication channel with the throttle space, the vacuum is transmitted to the working cavity of the diaphragm 24 of the starting device, but it is not enough to overcome the resistance of the diaphragm return spring. When steady flashes appear, the vacuum increases, the diaphragm 24 with the rail 23 retracts, and the rod 21 slightly opens the air damper 17. This compresses the spring located in the telescopic rod. The starting device, automatically opening or closing the air damper, does not allow excessive enrichment or depletion of the mixture.
Engine idle
The throttle valves are closed, the system vias are located just above the upper edge of the dampers, the air damper is fully open. The vacuum from under the throttle valve of the first chamber is transmitted through the holes of the idle system to the channels of the system. Under the action of vacuum, the fuel entering the emulsion well from the float chamber through the main fuel jet 34 rises to the fuel jet 33, mixes with the air entering through the air jet 26, and additionally mixes with the air entering through the vias and through the hole regulated by the screw 37, goes under the throttle valve. In this mode, the vacuum in the small diffuser is insignificant, and no fuel is supplied to the engine from the atomizer of the main dosing system.
The idle fuel jet 33 has a shut-off solenoid valve. When the voltage is removed from the solenoid valve, the valve needle closes the fuel jet 33, and the fuel supply stops, which excludes the possibility of the engine running with the ignition off.
Small and medium loads
The first mixing chamber works mainly, the required composition of the combustible mixture is ensured by the joint operation of the main dosing system and the idle system. When the throttle valve of the first chamber is opened, the vacuum in the atomizer increases, the fuel in the emulsion well rises, mixes with the air entering through the jet 19, and is carried into the atomizer. The vacuum in the mixing chamber is sufficient, so the fuel also comes from the holes of the idle system. Fuel consumption by both systems is limited by the main fuel jet 34.
When the throttle valve is opened approximately at an angle of 48°, the pneumatic actuator begins to open the throttle valve of the second chamber. Fuel begins to flow out of the sprayer of the main dosing system of the second chamber. The absence of failures in the operation of the engine' at the moment of the beginning of the opening of the throttle valve of the second chamber is provided by the openings 43 of the transition system, which comes into operation from this moment. In the future, the second chamber works similarly to the first.
Maximum engine power
The throttle valves of both chambers are fully open: the main dosing systems, the idling system, the transition system, and when the required vacuum is reached, the econostat are working. Due to some decrease in vacuum in the channels of the idle system and the transitional system at fully open throttle valves, the outflow of fuel from these systems is insignificant.
When sufficient rarefaction is reached in the small diffuser of the second mixing chamber, the econostat comes into operation, enriching the combustible mixture at full load. The fuel from the float chamber enters through the jet 8 of the econostat, mixes with the air coming from the jet 6, and then through the emulsion jet 10 and the atomizer 11 is sucked into the mixing chamber.
Accelerator pump
The accelerator pump operates in the engine load increase mode; while the necessary enrichment of the mixture is carried out by injecting an additional portion of fuel into the air flow of the first mixing chamber.
With a sharp increase in load (throttle valve opens abruptly) the accelerator pump drive cam on the damper axis acts on the lever 1, which compresses the spring placed inside the telescopic cup of the working diaphragm 48. Expanding, the spring moves the diaphragm, providing a smooth prolonged injection of fuel through the atomizer 15.
The operation of the pneumatic actuator of the throttle valve of the second chamber
At low engine loads, when the throttle valve of the first chamber is slightly open, the vacuum in the diffusers is not enough to operate the pneumatic drive, and under the action of the spring, the pneumatic drive rod is lowered down. As the load increases and the throttle valve of the first chamber opens, the vacuum in it increases and at a certain moment leads to the movement of the diaphragm mechanism up to its full stroke with simultaneous twisting of the spring on the axis of the throttle valve of the second chamber. However, the throttle valve of the second chamber remains closed until the throttle valve of the first chamber is opened at an angle of approximately 48°. With a wide open throttle valve of the first chamber and a large air flow (high speed crankshaft) throttle valve of the second chamber is fully opened. The throttle position of the second chamber is adjusted automatically, depending on the speed of the engine.
When the throttle valve of the first chamber is abruptly closed, the throttle valve of the second chamber is forcibly closed.