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Figure 15. Carburetor operation diagram: 1. Starter adjustment screw; 2. Diaphragm of the starting device; 3. Starter rod; 4. Shut-off electromagnetic valve; 5. Idle fuel jet; 6 Main air jet of the first chamber; 7. Idle air jet; 8. Idle flow channel; 9. Air damper; 10. Sprayer of the main dosing system of the first chamber; 11. Accelerator pump nozzles. 12. Second chamber main metering system nozzle: 13. Econostat injection tube; 14. Main air jet of the second chamber; 15. Air jet of the transition system of the second chamber. 16. Carburetor cover; 17 Float chamber balancing hole; 18. Needle valve; 19. Calibrated fuel bypass hole into the tank; 20. Fuel drain pipe into the tank; 21. Fuel filter; 22. Fuel supply pipe; 23. Diaphragm of the power mode economizer; 24. Air channel of the power mode economizer, 25. Fuel jet of the power mode economizer; 26. Ball valve of power mode economizer; 27. Float; 28. Fuel channel of the power mode economizer; 29. Fuel jet of economizer with tube; 30. Fuel jet of the transition system of the second chamber with a tube; 31. Emulsion tube of the second chamber; 32. Main fuel jet of the second chamber; 33. Carburetor body; 34. Output openings of the transition system of the second chamber; 35. Second chamber throttle valve; 36. Air channel of the starting device; 37. Idle air duct opening; 38. Throttle valve of the first chamber; 39. Slit of the transition system of the first chamber; 40. Idle mixture quality adjusting screw; 41. Carburetor heating unit; 42. Crankcase gas suction pipe; 43. Pipe for supplying vacuum to the vacuum regulator of the ignition distributor; 44. Main fuel jet of the first chamber; 45. Emulsion tube of the first chamber; 46 Idle Emulsion Channel; 47. Accelerator pump ball valve; 48. Accelerator pump diaphragm; 49. Accelerator pump drive lever; 50 Air damper drive handle rod; 51. Bracket for fastening the air damper drive rod casing; 52. Adjusting screw for opening the throttle valve of the first chamber; 53. Throttle actuator lever; 54. Air damper control lever; 55. Ball valve for fuel supply to the accelerator pump; 56. Accelerator pump drive cam; I. Carburetor operation at maximum engine power; II. Operation of the starting device; III. Operation of the carburetor at engine idle speed; IV. Operation of the carburetor when switching to medium engine loads; V. Operation of the accelerator pump.
The main metering system is fed from the float chamber, into which fuel enters through the needle valve 18. Through the main fuel jets 44 and 32, the fuel enters the emulsion wells. At sufficient vacuums in the sprayers of the main metering systems, the fuel mixes in the emulsion wells with air entering through the main air jets 6 and 14, and is sucked into the diffusers of the mixing chambers in the form of an emulsion. In the throttling mode, only the main metering system of the first chamber operates. The second chamber begins to open and operate when the throttle valve of the first chamber opens more than two-thirds.
The idle system provides the required composition of the combustible mixture at idle. In this case, throttle valves 38 and 35 are closed. Fuel from the emulsion well of the main metering system rises along the fuel channel, passes fuel jet 5, mixes with air from air jet 7 and the flow channel and then goes under the mixture quality screw 40 and into the throttle space.
The transition system of the first chamber ensures a smooth transition of the engine operation from idle to throttle modes. At the moment of opening the throttle valve of the first chamber, the gap 39 of the transition system falls under vacuum. Emulsion will also flow from it, ensuring a smooth transition.
The transition system of the second chamber ensures a smooth transition of the engine operation at the moment of the beginning of the opening of the throttle valve of the second chamber. At this moment, the holes 34 fall under vacuum; fuel from the float chamber rises up the tube through jet 30, air is mixed in from air jet 15, and the emulsion enters through the emulsion channel through the outlet openings under the throttle valve.
The economizer enriches the combustible mixture with the throttle valves fully open at speeds close to maximum. With the throttle valves open, the vacuum in the mixing chambers and tube 13 of the economizer increases significantly. Fuel from the float chamber enters through the jet 29 of the economizer and the injection tube 13 into the second mixing chamber.
The power mode economizer prevents a change in the enrichment degree of the mixture due to the pulsation of the vacuum under the throttle valve, especially when the crankshaft speed decreases, when the pulsation increases and the vacuum decreases. The economizer ball valve 26 is closed while the diaphragm 23 is held by the vacuum under the throttle valve. When the throttle valve 38 is significantly opened, the vacuum decreases somewhat, and the diaphragm spring opens the valve. Fuel passes through the valve, the economizer jet 25, is added to the fuel passing through the main fuel jet 44, and equalizes the enrichment of the mixture.
The diaphragm-type accelerator pump is driven by a cam on the axis of the first chamber throttle valve. When the throttle valve is opened sharply, the cam presses the lever 49 and through the spring in the pusher acts on the diaphragm 48, overcoming the resistance of the return spring. The diaphragm supplies fuel through the supply ball valve and injects it through the sprayers 11 into the mixing chambers. During the return stroke of the diaphragm, under the action of the return spring, fuel is sucked from the float chamber through the check ball valve 47 into the working cavity of the accelerator pump.
The starting device ensures the preparation of a rich combustible mixture when starting a cold engine. When turning the air damper control lever 54 counterclockwise by the rod 50, the throttle valve 38 of the first chamber opens slightly with its outer edge by the adjusting screw 52. At the same time, the expanding groove of the lever 54 releases the pin of the air damper lever, and it will be held completely closed by the return spring. The axis of the air damper is offset, so the air damper after starting the engine can open slightly by the air flow, stretching the spring, which ensures the leaner mixture.
The vacuum from the throttle space acts on the diaphragm 2 and can open the air damper slightly via the rod 3. The adjusting screw 1 allows you to regulate the amount of damper opening.
The forced idle economizer disables the idle system at forced idle (when braking the car with the engine, when driving downhill, when changing gears), excluding carbon monoxide emissions into the atmosphere.
The economizer includes a limit switch mounted on the adjusting screw 18 (see figure 12) the amount of idle mixture, electromagnetic shut-off valve 10, electronic control unit and electrical wires connecting the instruments.
At forced idle, if the rotation speed begins to increase, then the voltage on the winding of the electromagnetic shut-off valve 4 (see figure 13) is supplied by the electronic control unit until the crankshaft speed exceeds 2100 rpm, although the limit switch is closed to ground. At a higher speed, the electronic control unit turns off the power to the electromagnetic shut-off valve, as a result of which the fuel supply to the idle system is stopped.
When the engine crankshaft speed decreases at forced idle speed to 1900 rpm, the electronic control unit again begins to supply power to the valve winding, and it opens the fuel supply through the idle jet, the engine gradually enters idle mode, although the limit switch is closed to ground.