Starting device
Under the influence of a thermostatic bimetal spring of the automatic starter, air damper 1 (see diagrams) blocks the air flow into the carburetor duct. The throttle valve 2 of the 1st chamber is held in the slightly open position simultaneously by a three-pipe pneumatic actuator 3, the rod 4 of which is retracted by a spring from the stop of the throttle valve of the 1st chamber, and by a thermal force element 5 of the liquid heating system of the starting device, acting on the cam of the throttle valve of the 1st chamber. By slightly opening the throttle valve of the 1st chamber, a significant vacuum is created in the main metering system of the 1st chamber, which is necessary to start a cold engine and increase the idle speed of the crankshaft (see diagram «A»).
After starting the engine vacuum. arising in the intake pipeline, affects the pneumatic actuator 6 (see diagram «B»), which opens the air damper. With the transition to the operating mode, the thrust, driven by the throttle valve of the 1st chamber, open the air damper, as a result of which the fuel-air mixture is leaner and uninterrupted engine operation is ensured.
Idle system and transition system
After starting the engine, the thermal valve of the time relay blocks the communication of the pneumatic drive 3 of the throttle valve of the 1st chamber with atmospheric air, and its stem returns to the position corresponding to the idling of the warm engine. During the engine warm-up, the throttle valve of the 1st chamber is held in the slightly open position due to the smooth heating of the thermal power element of the liquid heating system of the automatic starting device.
Fuel from the float chamber enters through the main fuel jet 7 into the well of the emulsion tubes and the idle jet. Fuel is mixed with air entering through a hole regulated by a quality screw 2 (composition) mixtures. The fuel-air mixture exits under the throttle valve through slot 10 of the idle and transition system, which leads to a gradual increase in the engine speed.
The transition system of the 2nd chamber works similarly, providing an increase in the crankshaft speed as the throttle valve of the 2nd chamber opens.
Scheme of the idle system and the transition system of the 1st chamber of the Pierburg 2E2 carburetor: 2 - throttle valve of the 1st chamber; 3 - pneumatic actuator of the throttle valve of the 1st chamber; 7 - main fuel jet of the 1st chamber; 8 - idle fuel jet; 9 - quality adjusting screw (composition) mixtures; 10 - injection slot of the idle air-fuel mixture and the transition system; 11 - pneumatic valve of the mixture heating system with a thermal time switch
Scheme of the Pierburg 2E2 carburetor when starting a cold engine: 1 - air damper; 2 - throttle valve of the 1st chamber; 3 - pneumatic actuator of the throttle valve of the 1st chamber; 4 - rod of the pneumatic actuator of the throttle valve of the 1st chamber: 5 - heat-power element; 6 - pneumatic actuator of the air damper
Main dosing system
Fuel through a needle valve, the flow area of which is regulated by a float, fills the float chamber and is held here at a constant level. The needle valve is hooked to the float tongue.
From the float chamber under the action of vacuum, fuel through the main fuel jet 7 (see diagram) The 1st chamber enters the well of the emulsion tube, where it mixes with the air leaving the opening of the main air jet 12. The resulting emulsion is sprayed by the air flow passing through the small and large diffusers 13.
The power mode economizer is included in the main dosing system of the 1st chamber. When the vacuum drops in the throttle valve zone 2 of the 1st chamber, caused by a significant opening of the throttle valve, there is no vacuum in the diaphragm cavity of the power modes economizer housing 14, the valve 15 of which, under the action of a spring, opens the channel 16 for supplying additional fuel to the fuel jet of the main metering system 1 th camera.
The main dosing system of the 2nd chamber works similarly, in which an ecostat is included instead of an economizer for power modes. The enrichment of the fuel-air mixture at full load in the 2nd chamber is provided by spraying clean fuel under the action of a strong rarefaction through the injection tube 17 of the econostat, the outlet of which is located above the mixture formation zone.
Scheme of the main dosing systems of the Pierburg 2E2 carburetor: 2 - throttle valve of the 1st chamber; 7 - main fuel jet of the 1st chamber; 12 - main air jet of the 1st chamber; 13 - diffuser; 14 - housing of the pneumatic drive of the power modes economizer; 15 - economizer valve; 16 - fuel supply channel from the economizer; 17 - econostat injection tube
Accelerator pump
Opening throttle 2 (see diagram) Cam 18 of the 1st chamber actuates the lever 19 of the accelerator pump drive and the pump 20 pumps the fuel sucked into the float chamber into the mixture formation zone through the check valve and sprayer 21.
Pierburg 2E2 carburetor accelerator pump diagram: 2 - throttle valve of the 1st chamber; 16 - accelerator pump drive cam; 19 - drive lever; 20 - accelerating pump; 21 - atomizer
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