There are basis principles of K Jetronic system working are continuous fuel injection and direct air flow measurement. This mechanical system does not include an engine-driven fuel pump. The main goal of K Jetronic system is to continuously meter fuel in proportion to the amount of air at the intake stroke. The system measures and analysis the air flow and takes into account all changes in the engine’s operation to reduce the toxicity of the exhaust gases by the operation.
How K Jetronic system works
An air enters to the air filter, then it enters into the engine cylinders through the air flow sensor and throttle valve. Therefore, the rotary-type fuel pump with electric drive supplies fuel from the tank. The fuel enters to the fuel accumulator through the filter. The special pressure regulator supports a constant pressure in the system. The fuel directs from the fuel distributor to the injectors, and the rest fuel returns to the tank.
Elements of K Jetronic System
Now you will see the main elements of K Jetronic system and will know how it works.
Electronic mixture control unit
The electronic mixture control unit consists of a fuel distributor and an air flow sensor.
Air flow meter
The air flow meter consists of a swivel plate and a diffuser, a counterweight, a guide plunger. The position of the gauge plate indicates the air flow and this position transmits the force to the control plunger of the fuel distributor.
The amount of fuel can be adjusted by changing the areas of the metering holes in the fuel rail. The number of holes corresponds to the number of cylinders in the engine. The size of the metering holes affects the position of the control plunger. The fuel distributor consists of:
Fuel distributor anatomy:
1 – diaphragm; 2 – to the nozzle; 3 – control plunger; 4 – dispensing hole; 5 – differential pressure regulator.
Air assist valve
The air assist valve supplies additional air to the engine as the engine warms up. This is necessary to compensate for frictional power losses, maintain normal engine idling, and increase engine speed to warm up the engine quickly.