Throttle valves
In one of the intake pipes there are two throttle valves. The smaller of these dampers is connected by a cable to the pedal "gas" inside the car. With its help, the air supply to the engine is regulated to about half the pedal travel "gas". Further pressing the pedal "gas" the actuator opens a second, larger flap. When the pedal is fully depressed, both throttles are fully open.
Mixture regulator
This is one of the main parts of the injection system, it includes an air quantity meter and a fuel dispenser. They function like this:
- The light metal plate of the air quantity meter is located in the direction of the air flow to the engine. This plate rises with the stroke of the piston during the intake stroke and the more, the more air needs to be brought to the throttle. With the help of a system of levers, the amount of rotation of the plate is transmitted to the fuel dispenser.
- The fuel dispenser mainly consists of a control piston and a slotted housing. For each cylinder of the engine in the body there is a slot through which fuel enters the corresponding injector. The control piston closes or opens the slot more or less and, according to the position of the air-measuring plate, passes the required amount of fuel.
- System pressure: The fuel pump delivers pressurized fuel to the injection system. Here is the first stage of the pressure regulator in a separate housing. It relieves excess pressure and leaves a pressure of 6.6 bar in the fuel system. This pressure is present in the dispenser, fuel lines and injectors.
Pressure regulator
The pressure regulator, together with the vacuum chambers, determines the amount of mixture. This is done with differential pressure valves, which usually perform a different task. Fuel supply to rarefaction chambers (from which the required amount of the mixture comes out) carried out using a pressure regulator. If it passes a lot of fuel to the vacuum chambers, the pressure inside the chambers increases, as a result of which the differential pressure valve membranes sag in the direction of the valve openings. In this case, less fuel is supplied to the injectors. The reverse action happens in the same way. The pressure regulator receives control signals from the control unit. This takes into account lambda control, temperature and engine load. The pressure regulator is located on the side of the mixture regulator.
Injectors
They inject fuel into the fuel passage before the intake valve of the corresponding cylinder until the fuel pressure reaches 3.7-4.8 bar (depending on engine type) At the same time, they open up to 200 times per second, so that the fuel can be atomized especially finely.
Pressure regulator
The pressure regulator, together with the vacuum chambers, determines the amount of mixture. This is done with differential pressure valves, which usually perform a different task. Fuel supply to rarefaction chambers (from which the required amount of the mixture comes out) carried out using a pressure regulator. If it passes a lot of fuel to the vacuum chambers, the pressure inside the chambers increases, as a result of which the differential pressure valve membranes sag in the direction of the valve openings. In this case, less fuel is supplied to the injectors. The reverse action happens in the same way. The pressure regulator receives control signals from the control unit. This takes into account lambda control, temperature and engine load. The pressure regulator is located on the side of the mixture regulator.
Injectors
They inject fuel into the fuel passage before the intake valve of the corresponding cylinder until the fuel pressure reaches 3.7-4.8 bar (depending on engine type) At the same time, they open up to 200 times per second, so that the fuel can be atomized especially finely.
Scheme of the KE-Motronic injection system
1 injector
2 Cold start valve
3 Mixture adjuster
4 Pressure regulator
5 Diaphragm pressure regulator
6 Fuel tank
7 Electric fuel pump
8 Filter
9 Idle speed stabilization valve
10 Fuel cell
11 Control unit
12 Throttle shaft switch
13 Coolant temperature sensor
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