Depending on the model of the car, different types of carburetors are mounted.
In models with carburetor engines, carburetors such as Sofex, Zenith, Pferburg are installed, depending on the volume and power of the engine. The carburetor type designation is located on the side of the body.
The carburetor is used to form a mixture of fuel and air in the appropriate proportion, as well as to regulate the amount of mixture entering the combustion chamber (at all engine speeds).
Engine power at a given time depends on the amount of mixture supplied.
The ideal would be a carburetor that would form the optimal mixture in all conditions. Of course, this is impossible, but carburetors are equipped with an increasing number of systems, both mechanical and electronic, to optimize the composition of the mixture.
Main carburetor systems:
- Launch system.
- idle system.
- Main fuel system.
- Accelerator pump.
- enrichment system (at full load).
These systems only work at a certain moment (starting system or accelerating pump) or at a certain rotation speed (as idle system or main fuel system). Since this is not enough, additional auxiliary systems are also used to obtain the optimal mixture composition.
These are systems that enrich or lean the mixture, depending on the ambient temperature, engine temperature, rotation speed, throttle angle, etc. The injection system of gasoline performs the same functions as the carburetor. The main differences are in the device. The operating element of the injection system is a solenoid valve that opens under the influence of pulses from the electronic control module.
The feed pump generates pressure in front of the valve. To inject the appropriate amount of fuel, it is enough to open the valve for a longer and shorter period of time. How long the valve will be open is decided by the microprocessor, which determines the portion of fuel, depending on even more parameters than given for the carburetor. Among other things, this is the ignition timing, the composition of the exhaust gases in the exhaust pipe, the amount of air passing through the drive manifold, the gear currently engaged, etc. This allows much more precise control of the fuel supply.
Mechanical type fuel pump in models with 1.1 and 1.3 dm engines3 mounted on the engine head and actuated by a pusher from the camshaft.
In engines 1.6 and 1.8 dm3 the fuel pump is attached to the engine housing and is driven directly through the countershaft cam. Its main task is to suck fuel from the tank and supply it to the carburetor float chamber.
The carburetor consists of a housing in which two return valves are installed. One makes it impossible to move back the column of fuel located in the pipe between the pump and the carburetor. The second makes it impossible for fuel from the pump to enter the fuel tank during the compression stroke. The fuel tank is located at the rear of the car, under the trunk floor. The filler funnel is located in the rear right fender. The air is removed by means of an external air removal system.
The fuel system includes a return pipe, which is connected either to a tee located between the carburetor and the fuel pump, or directly to the carburetor float chamber. The narrowing in the return pipe regulates the supply of fuel to the tank.
The passage of fuel through the return pipe must be under pressure, because. otherwise, the fuel will go into the tank instead of the float chamber.
The return pipe is used to eliminate pressure in the pipe between the fuel pump and the needle valve after the engine has started. In engines without a return pipe, pressure remains in the pipe after the engine is started. Even a small leakage of the needle valve contributes to the ingress of fuel into the carburetor neck, from there, evaporating, it gets out, polluting the environment.
An ordinary fuel filter is mounted in the supply pipe in front of the fuel pump, which serves to trap debris and prevent it from entering the carburetor. Vehicle models with fuel injection have a Bosch K-Jetronic fuel injection system instead of a carburetor. In this case, an electric fuel pump is mounted at the rear of the vehicle near the fuel tank. The fuel tank supply assembly includes a feed pump and a fuel filter. Carburetor (or injection) The power supply system is the most important node of the engine, which determines its performance and fuel use.
The carburetor is finely tuned for the engine it is running on and should not be adjusted unnecessarily.
Since most carburetor adjusting bolts are protected with nozzles, plugs, or paint to make it impossible to change their setting, adjustment is not possible without destroying these protections. Therefore, it is recommended that the adjustments described in this section be made only when necessary. All other work should only be left to a specialist. For most carburetors, repair kits are available that include all the necessary parts, In the case of a carburetor that has a significant mileage (over 150,000 km) it would be better to replace the entire carburetor with a new one or a remanufactured one with a warranty.
Attention: When working on any part of the power system, you must first always disconnect the wire clamp to the battery ground. All components of the power system must be kept clean. Before removing the elements of the power system or fuel pipes, it is necessary to carefully clean the places around these elements or connections before dismounting them. Where necessary, install new washers, O-rings, flexible tubes, clamps, etc
The air filter assembly includes a replaceable paper filter insert as well as an automatic temperature controller. The temperature regulator is used to switch the valve located in the air filter housing. At low temperatures, this valve opens a channel through which warm air near the exhaust manifold is sucked into the air filter. This improves the conditions for fuel evaporation. The exhaust system in all car models is divided into sections in order to facilitate the replacement of its individual components.
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