The appearance of the carburetor 2BE:
2 - throttle potentiometer of the 1st chamber; 3 - air damper servo; 4 - throttle servo of the 1st chamber; 12 — throttle actuator of the 2nd chamber; 20 - carburetor cover; 21 - carburetor body; 22 - throttle body; 24 - idle switch connector; 29 - air damper.
Device Features
Carburetor emulsion type, two-chamber, with sequential opening of throttle valves. It features a compact design and low height. Each chamber has a float chamber and a separate float, as a result of which the carburetor is insensitive to the action of the centrifugal force that occurs during turns and inertia during sharp accelerations and decelerations. The carburetor can be installed along the longitudinal or transverse axis of the vehicle. Thanks to the use of flooded jets (those. they are located below the fuel level) and the special arrangement of fuel channels 8 in the carburetor completely excludes the possibility of the formation of gasoline vapors. The carburetor has two independent economizers with flooded jets. This ensures optimal adaptation of the carburetor to all engine operating conditions. The following is a description of the design and operation of the main parts of the carburetor.
Throttle body (pos. 22 see pictures)
Throttle valve axes are located in the throttle body, each of which rotates in two bearings, levers, return springs and stops of the throttle valve axes, as well as a quality adjusting screw (composition) idle mixture. Emulsion channels of the idle system, channels of the transition systems of the 1st and 2nd chambers and holes for the shut-off (blocking) valves of the 2nd chamber are made directly in the body of the throttle body. Holes for vacuum sampling for the vacuum corrector of the ignition distributor sensor and for the electro-pneumatic drive of the throttle valve of the 1st chamber are connected to them by hoses.
In the opening zone of the throttle valve of the 1st chamber, a hole was drilled for vacuum sampling to control the air valve of the engine braking system.
Carburetor body (pos.21)
In addition to two float chambers, diffusers and corresponding holes, a fuel jet of the transition system of the 2nd chamber is located in the carburetor body. The connecting tube of the control system of the 2nd chamber is pressed into the carburetor body. The housing is equipped with a pneumatic actuator of the diaphragm type throttle valve of the 2nd chamber and servomotors of the air damper and throttle valve of the 1st chamber.
Throttle valve potentiometer 1st chamber (pos.2)
The potentiometer is designed to correct the position and track the movements of the throttle valve of the 1st chamber. Information from the potentiometer is sent to the controller. The potentiometer rotates around its axis and has a built-in return spring to compensate for the gap. In order to account for variations due to manufacturing tolerances, the potentiometer is mechanically linked to the first chamber throttle valve axis.
Air damper servo (pos. 3)
The choke servo is controlled by the controller and determines the composition of the air-fuel mixture during cold start, warm-up, acceleration and partial engine load. The enrichment of the combustible mixture is provided by a pressure drop due to the closing of the air damper and the movement of the needle of the idle air jet depending on the position of the air damper (thereby reducing the flow area of the idle air jet).
Air-fuel mixture adjustment (and depending on the amount of incoming air and the position of the air damper) mainly depends on the available torque in the area of the air damper, the axis of which is offset, so its servo works as a torque motor. The torque produced by the engine, in turn, depends on the angular position of the air damper and on the electrical voltage supplied to it.
The reaction torque is generated by the intake air pressure deflecting the choke and the action of the idle air jet needle spring. The servo drive uses an electric motor with a bell-shaped armature, which has a small moment of inertia and provides high accuracy in regulating the speed of movement of the servo drive and the air damper itself. The moment from the servo drive to the axis of the air damper is transmitted by thrust.
Throttle actuator 1st chamber with idle switch (pos. 4)
The throttle valve actuator of the 1st chamber is an electro-pneumatic actuator that controls the filling of the engine cylinders. The servo pusher is moved by means of a diaphragm that is subjected to vacuum and overcomes the resistance of the return spring. The necessary working pressure is generated by two solenoid valves, one of which operates depending on atmospheric pressure, and the other - on the vacuum in the intake manifold.
A signal about the position of the servo pusher is taken from the potentiometer built into the servo drive. The pusher moves the throttle valve using a lever mounted on its axis.
The controller constantly adjusts the filling of the cylinders. This allows you to maintain a constant idle mode under any operating conditions and control the operation of the carburetor during a cold start, correction of the engine operation immediately after starting, during warm-up and when the fuel supply is cut off when the engine speed drops and the engine stops.
An idle switch is built into the pusher of the throttle servo of the 1st chamber. When pressing the idle switch with the throttle control lever of the 1st chamber (circuit breaker open) the controller receives information on the basis of which the idle speed of the engine is regulated. After the throttle control lever of the 1st chamber moves away from the idle switch, the controller receives information about an increase in the crankshaft speed.
In the part of the throttle valve servo drive of the 1st chamber, which is exposed to the intake manifold vacuum, a check valve is built into its body. To prevent contamination of the servomotor, a filter is installed in the atmospheric pressure supply hose.
Carburettor cover (pos. 20)
Unlike the cover of conventional carburetors, a large number of parts are placed in the 2BE carburetor cover, the main of which are:
- fuel supply pipe with filter;
- sprayers of the 1st and 2nd chambers;
- two needle valves;
- two floats;
- shut-off (blocking) 2nd chamber valve (in the fuel supply channel to the 2nd chamber).;
- air damper with an offset axis and a lever for controlling the needle of the idle air jet of the 1st chamber;
- idle air jet of the 1st chamber with an idle air supply adjustment needle depending on the position of the air damper;
- idle fuel jet with emulsion tube;
- main fuel jets of the 1st and 2nd chambers;
- main air jets with emulsion tubes of the 1st and 2nd chambers;
- transitional system of the 2nd chamber;
- calibrated tubes of economizers for power modes of the 1st and 2nd chambers and tubes for enriching the combustible mixture.
The appearance of the carburetor 2BE:
1 - throttle body; 2 - float chambers; 3 - carburetor cover; 4 - air damper; 5 - idle air jet needle; 6 - throttle servo of the 1st chamber; 7 - idle switch; 8 - idle switch connector; 9 - throttle potentiometer of the 1st chamber; 10 - air damper servo; 11 - shut-off (blocking) valve of the 2nd chamber; 12 - pneumatic drive of the 2nd chamber.
Section of the carburetor 2BE:
18 - fuel supply pipe with filter; 52 - float of the float chamber of the 1st chamber; 53 - needle valve of the 1st chamber; 56 - needle valve of the 2nd chamber; 57 — float of the float chamber of the 2nd chamber; 59 - shut-off valve of the 2nd chamber; 60 - aperture; 61 - spring of the shut-off valve of the 2nd chamber.