Fuel Delivery and Air Induction: Description and Operation

Fig. 59 Bosch K-Jetronic fuel injection system:

With the Bosch K-Jetronic (CIS) injection system, air flow through the intake manifold is measured by the air sensor which controls the fuel distributor.
Fuel from the tank is delivered to the fuel distributor by the electric fuel pump via an accumulator and filter, Fig. 1.
The fuel distributor controls the quantity of fuel delivered through the injectors to each cylinder.
The control pressure regulator provides fuel enrichment during engine warm-up by changing fuel pressure on top of the control plunger inside the fuel distributor.
The cold start valve provides additional fuel during cold starting.
The auxiliary air regulator supplies additional air during engine warm-up as a fast idle provision.
The oxygen sensor system was introduced which controls the amount of fuel delivered to the engine. The oxygen sensor, located in the exhaust pipe, sends a variable voltage signal to the electronic control unit depending on the amount of oxygen in the exhaust. The electronic control unit then causes the frequency valve to vary the amount of fuel delivered to the engine.