Work on load modes
The fuel electric pump takes fuel from the fuel tank and pumps it under a pressure of about 5 kgf/cm2 into the dispenser through the fuel filter and pressure accumulator.
Fuel under supply pressure fills the lower chambers of the dispenser-distributor and presses the diaphragms of the differential pressure valves to the fuel supply pipes to the injectors. Through the slots in the walls of the distribution plunger, fuel under pressure penetrates into the upper chambers of the dispenser-distributor. The amount of fuel entering the upper chambers of the dispenser-distributor varies depending on the vertical movement of the distribution plunger. When the total fuel pressure in the upper chambers and the spring pressure exceeds the fuel supply pressure in the lower chambers, the valve diaphragms are lowered, opening the access of fuel through the tube to the injection nozzle. As soon as the pressure in the upper chambers of the dispenser-distributor decreases, the valve diaphragms return to their original position. Due to the uniform frequency of opening and closing of the fuel supply channels to the injectors, a constant fuel pressure is established. The displacement of the pressure disk of the air flow meter is transmitted through the lever to the distribution plunger, which returns to its original position due to the counteracting fuel pressure in the upper part of the dispenser-distributor.
The counter pressure is generated by the supply pressure and is controlled by the pilot pressure regulator. A bypass valve installed in the throttle area provides a minimum vacuum in the air flow meter when the engine is idling. The degree of opening of the valve is regulated by a needle.
Starting a cold engine and idling
The fuel electric pump creates the operating pressure of the fuel in the system. At the moment of starting a cold engine and for a certain time, the starting injector injects an additional amount of fuel into the intake pipe. The duration of operation of the starting injector is determined by the thermal timer depending on the temperature of the coolant.
The idle speed solenoid valve is installed in the air duct parallel to the throttle valve. The valve provides additional air to the engine to increase the idle speed of the cold engine and maintain the idle speed within the specified limits (950-1050 rpm). The degree of valve opening is set by the electronic idle stabilization and forced idle control unit, depending on the temperature of the coolant and the engine speed. Additional enrichment of the air-fuel mixture when starting and warming up a cold engine is achieved due to a greater rise in the distribution plunger of the dispenser-distributor due to the fact that the control pressure regulator reduces the back pressure.
While the engine is not warmed up, the bimetal spring compresses the diaphragm valve spring, opening the fuel drain channel, which leads to a decrease in the control pressure on the distribution plunger.
Hot engine start
In order to completely eliminate fuel evaporation after the engine is stopped, the pressure in the injection system is maintained for some time by a pressure accumulator, which temporarily interrupts the flow of fuel into the tank.
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