Main dosing system (see diagram)
Scheme of the main dosing system: (1) — fuel intake; (2) - supply of main air; (3) — air supply for pressure compensation; 33 - main air jet; 36 - emulsion tube; 37 - spray jet; 38 - diffuser; 39 - throttle valve; 40 - main fuel jet.
The diffuser jet outlet is located in the narrowest part of the diffuser. The spray jet is connected in the upper part to the hole into which the emulsion tube is pressed. The cross channel connects the emulsion tube with the main air jet.
Through the main fuel jet located in the float chamber (which can be accessed from the outside by unscrewing the screw plug), the fuel enters the well of the emulsion tube. When the engine is not running, the fuel in the float chamber and the well of the emulsion tube is at the same level.
Under the action of vacuum in the inlet pipeline, fuel is sucked through the main fuel jet and supplied to the spray jet. There is a small hole at the top of the spray jet to prevent the siphon effect.
When the vacuum increases, some air enters through the main air jet and the pressure equalizes. The incoming air passes through the holes in the emulsion tube, mixes with the fuel going through the main fuel jet, forming an air-fuel mixture (emulsion), while the composition of the mixture is regulated depending on the operating mode of the engine.
Idle system (see diagram)
Scheme of the carburetor at idle: (1) — fuel intake; (2) - supply of main air; (3) — an air intake of system of idling; (5) - the supply of an air-fuel emulsion of an additional idling system; (6) - block of the electromagnetic shut-off valve (7) - solenoid shut-off valve in the open position; 4 - carburetor cover; 9 - idle fuel jet; 13 - adjusting screw for the amount of mixture of the additional idling system; 14 - quality adjusting screw (composition) idle mixtures; 16 - electromagnetic shut-off valve; 32 - idle air jet; 39 - throttle valve; 40 - main fuel jet; 49 - fitting.
The primary idle system is designed to prepare only part of the air-fuel mixture necessary for the engine to operate at a well-defined idle speed. The adjusting screws of this system are locked during assembly to ensure that the factory setting is not violated. Another part of the fuel-air mixture necessary to ensure the engine is idling is created in an additional circuit.
Fuel for the primary idle system is drawn behind the main jet (normal idle /ode) from the well of the emulsion tube, is dosed by the idle fuel jet, after which it mixes with the air entering through the idle air jet, and forms an emulsion. This part of the emulsion is brought down and combined with the fuel-air mixture created in an additional circuit in the channel in front of the electromagnetic jet.
The additional idle circuit also directs the fuel-air mixture to the slots of the transition system. This ensures smoother carburetor operation during the transition from idle to the main metering system.
Fuel for the formation of a combustible mixture in an additional idle circuit comes from the float chamber through a calibrated tube and is dosed with a special jet.
The necessary air is sucked into the mixing chamber, where a fuel-air mixture is formed. An additional portion of the emulsion enters through the hole, the diameter of which is regulated by the adjusting screw for the amount of mixture of the additional idling system. The working mixture, the amount of which depends on the position of the adjusting screw, is added to the emulsion flowing through the idle channel, and the entire volume of the mixture enters the mixing chamber. Air is added to the combustible mixture thus obtained through the throttle valve gap, the value of which is finely adjusted. The process of preparing the idle mixture is thus completed.
When the ignition is turned off, the electromagnetic shut-off valve closes the channel for supplying the working mixture common to the primary and additional idling systems. This prevents the engine from running after the ignition is turned off.
When the adjusting screw for the amount of the mixture of the additional idling system is unscrewed, the flow of the fuel-air mixture increases and, as a result, the engine speed increases. Accordingly, when the adjusting screw is turned in, the flow of the fuel-air mixture of the additional idle system is reduced and the idle speed of the crankshaft is reduced.
When adjusting the idle speed of the engine using the adjusting screw for the amount of mixture of the additional system, the ratio of fuel and air in the working mixture formed in this circuit remains unchanged. Violation of the adjustment does not affect the CO content in the exhaust gases when the engine is idling. This makes it much easier to adjust the idle speed of the engine.
Accelerator pump (see diagram)
Scheme of the accelerator pump: (1) — fuel intake; (2) - supply of main air; (3) - air supply for pressure compensation; 31 - needle valve float; 33 - main air jet; 34 - spray tube; 36 - emulsion tube; 37 - tip of the spray jet; 39 - throttle valve; 40 - main fuel jet; 41 - check ball valves (top in open position, bottom in closed position); 42 - adjusting nut; 43 - accelerator pump diaphragm.
With a sharp opening of the throttle valve, the accelerator pump of the carburetor provides the injection of such an amount of fuel that will be enough to ensure smooth activation of the main fuel jet.
The cavity of the accelerator pump is filled with gasoline injected into the float chamber. In the non-working position, the accelerator pump diaphragm is pressed against the drive lever under the action of a spring. When the throttle is opened, the diaphragm moves forward, forcing fuel through the atomizer tube into the mixing chamber. The performance of the accelerator pump depends on the amount by which the drive lever deviates during acceleration.
The non-return ball valve prevents fuel from returning to the float chamber during the injection period. Another ball valve at the outlet of the channel of the accelerating pump blocks the access of air from the mixing chamber to the pump cavity while fuel is pumped into it.
At a certain vacuum in the mixing chamber, an additional amount of fuel enters here through the channel of the accelerator pump, enriching the combustible mixture.
Solex 35 POSIT carburetor in section: 1 - throttle valve; 2 - quality adjusting screw (composition) idle mixtures; 3 - adjusting screw for the amount of mixture of the additional idling system; 4 - economizer valve power modes; 5 - ball valves; 6 - idle jet; 7 - needle valve; 8 — economizer piston; 9 - idle air jet; 10 - ventilation channel of the float chamber; 11 - main air jet; 12 - spray accelerator pump; 13 - air damper; 14 - econostat injection tube; 15 - tip of the spray jet; 16 - econostat valve; 17 - air damper control cam; 18 - stock; 19 - restrictive screw of the throttle actuator; 20 - main fuel jet; 21 - emulsion tube; 22 - vacuum supply channel; 23 - diffuser.
The main details of the Solex 35 POSIT carburetor: 1-6 - details of the automatic starting device; 7 - carburetor cover; 8 - gasket; 12, 14 - air damper actuators; 16, 17 - needle valve and gasket; 18 - float; 19, 20 - seat and needle valve of the power mode economizer; 21 - main air jet; 22 - main fuel jet; 23 - thrust screw; 24 - carburetor body; 25 - spring; 26 - accelerator pump diaphragm; 27 - cover; 28 - diffuser; 29 - spacer; 32 - quality adjusting screw (composition) idle mixtures; 34 - adjusting screw for the amount of the mixture of the additional idling system; 36 - throttle body.
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