Power supply system for engines with fuel injection system «K-Jetronic»: 1 - fuel tank; 2 - fuel pump; 3 - fuel accumulator; 4 - fuel filter; 5 - control pressure regulator; 6 - dispenser-distributor of fuel; 7 - air flow meter; 8 - throttle body; 9 - connecting air duct; 10 - inlet pipeline; 11 - laying of the inlet pipeline; 12 - bracket for air filter and air flow meter; 13 - air filter; 14 - air filter housing; 15 - air supply hoses; 16 - thermostat
The location of the fuel injection system «K-Jetronic»: 1 - fuel filter; 2 - dispenser-distributor of fuel; 3 - control pressure regulator; 4 - air flow meter; 5 - starting nozzle; 6 - additional air supply valve
The principle of operation of the fuel injection system «K-Jetronic»
Pressurized fuel is continuously supplied to the injection nozzles located directly in front of the intake valves. The amount of fuel injected by the injectors is dosed by the pressure of the incoming fuel depending on the engine load (vacuum in the inlet pipeline) and coolant temperature. The amount of injected fuel is adjusted by a metering device, which operates under the influence of an air flow meter and a control pressure regulator. During engine warm-up, the latter regulates the control pressure depending on the vacuum in the intake manifold and on the temperature of the coolant.
The amount of air supplied is constantly measured by the air flow meter, and the amount of fuel injected is strictly proportional to the amount of air supplied (except for a number of engine operating modes, such as cold start, full load, etc.) and regulated by a fuel dispenser.
Work on load and idle modes
Fuel electric pump 1 (see diagram) takes fuel from the fuel tank and pumps it 2 under a pressure of about 5 kg / cm2 into the dispenser-distributor 2 through the fuel filter 4 and the fuel accumulator 3.
Fuel under supply pressure fills the lower chambers 5 of the dispenser-distributor and presses the diaphragms of the differential pressure valves 6 against the pipes 7 for supplying fuel to the injectors. Through the slots in the walls of the distribution plunger 8, 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.
Scheme of the injection system «K-Jetronic» on load and idle modes: 1 - fuel pump; 2 - dispenser-distributor of fuel; 3 - fuel accumulator; 4 - fuel filter; 5 - chamber of the dispenser-distributor; 6 - differential pressure diaphragm valve; 7 - tube for supplying fuel to the injection nozzle; 8 - distribution plunger; 9 - injection nozzle; 10 - pressure disk of the air flow meter; 11 - control pressure regulator; 12 - throttle valve; 13 - idle adjustment screw
Scheme of the injection system «K-Jetronic» when starting a cold engine: 1 - fuel pump; 8 - distribution plunger; 11 - control pressure regulator; 14 coolant temperature sensor; 15 starting nozzle; 16 - valve for additional air supply; 17 - diaphragm valve for control pressure adjustment; 18 - bimetallic spring for controlling the control pressure adjustment valve
Cat yes, the total fuel pressure in the upper chambers and the spring pressure exceed the fuel supply pressure in the lower chambers, the valve diaphragms 6 are lowered, opening the access of fuel through the tube to the injection nozzle 9 As soon as the pressure in the upper chambers of the dispenser-distributor decreases, the valve diaphragms 6 return 8 to the 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 10 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 regulated by the control pressure regulator 11.
The valve 16 additional air supply is installed in the air channel, made parallel to the throttle valve 12. It provides a minimum vacuum in the air flow meter when the engine is idling. The degree of opening of the additional air supply valve is regulated by the adjusting screw.
Starting a cold engine
The fuel electric pump 1 instantly 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 15 injects an additional amount of fuel into the intake manifold.
The duration of the starting injector is determined by a thermal timer depending on the temperature of the coolant. Valve 16 provides additional air to the engine to increase the idle speed of the cold engine. Additional enrichment of the air-fuel mixture when starting and warming up a cold engine is achieved due to a freer rise of the distribution plunger 8 of the dispenser-distributor due to the fact that the control pressure regulator 11 reduces the counteracting return pressure.
While the engine is not warmed up, the bimetallic spring 18 compresses the spring of the diaphragm valve 17, opening the fuel drain channel, which leads to a decrease in the opposing pressure on the distribution plunger.
Hot engine start
To completely eliminate fuel evaporation after the engine is stopped, the pressure in the injection system is maintained for some time by the fuel accumulator, which temporarily interrupts the flow of fuel into the tank.
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