Audi 80/Avant (B4)
since 1991-1995 release
Repair and operation of the car
+ Technical specification
+ System of production of the fulfilled gases
+ Cooling system
+ Fuel tank and fuel pump
+ Air filter and airintaking channels
- System of injection
+ System of injection Mono-Motronic
+ System of injection Digifant
- System of injection KE-III-Jetronic
Malfunctions and independent diagnostics
Check of separate elements
Search of malfunctions
Removal of components
Check of the mode of idling and analysis of exhaust gases
List of malfunctions
+ Systems of injection of MPI and MPFI
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Signaling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ Body elements
+ Search of malfunctions
Scheme of action of system of injection KE-III-Jetronic. Red fuel is shown, the arriving air is emitted light pink.
Look on the proofreader of composition of gas mixture of system of injection of KE-III-Jetronic
For the best understanding of full functioning of our system of injection for a start it is necessary to explain the major details and concepts:
In a final collector in a branch pipe there are two butterfly valves. Smaller of these gates it is connected by a cable of the drive of "gas" with a pedal in salon. It doses a stream of inlet air in the engine. If the pedal of an accelerator is squeezed out stronger, then draft opens the second, big gate. In the provision of full "gas" both gates are open.
Proofreader of composition of gas mixture
It represents the main component of system of injection and consists of a flowmeter of air and the batcher of fuel. They act so:
Pressure in system
The fuel pump in the fuel tank pumps over fuel under pressure in system of injection. The first instance is the regulator of system pressure in the separate case here. It reduces elevated pressure and leaves for fuel system only from 6,1 to 6,5 bars. This pressure, pressure in system, works in the batcher, a fuel-supply line and vpryskny nozzles.
The regulator of pressure is responsible for composition of mix. It occurs as follows: intake of fuel to the lower cameras (via which it is possible to affect amount of mix) happens via pressure regulator. If it passes a lot of fuel in the lower cameras, then pressure increases in the lower cameras. Investigation: membranes of so-called valves of pressure differences cave in towards valvate openings – towards vpryskny nozzles less fuel gets. On the contrary it, of course, works in the same way.
The regulator of pressure receives commands from the control unit. It occurs depending on a lambda regulation, temperatures of the engine and load of it.
As soon as pressure of fuel reached 4,3 — 4,6 bars, nozzles give gasoline to the canal in front of the valve of the corresponding cylinder. At the same time they open to 2000 times a second thanks to what gasoline is sprayed especially thinly.
The control unit regulates composition of mix of the engine via pressure regulator. In order that this management was based on something, the control unit obtains data on engine temperature, rotation frequency, starting processes, the provision of a valvate lock (from idling to full loading). Here the signal a lambda probe, and also additional data from system of ignition, the sensor of atmospheric pressure and from the automatic transmission is added.
Distributive valve of stabilization of idling
Function: the valve opens the air channel bypassing a butterfly valve. Effect at the same time following: because of the increased amount of air the flowmeter of air "believes" that the butterfly valve was a little slightly opened and therefore provides respectively the increased intake of fuel. Desirable result: increase in frequency of rotation. How many will in addition arrive air, defines the control unit of system of injection KE-III-Jetronic, namely according to rotation frequency of time at present. Thereby electronics seeks to return rotation frequency to standard range.
Starting fuel valve
It is a nozzle with the electromagnetic drive which depending on engine temperature at start gives additional amount of small sprayed fuel to an inlet collector. Duration of injection defines the control unit of system of injection KE-III-Jetronic.
Sensor of angular movement of a butterfly valve
In Audi 80 two sensors of angular movement of a butterfly valve are mounted. They signal the following data:
Interruption in supply of fuel in the mode of compulsory idling (the movement by a setup)
Already mentioned regulator of pressure stops fuel supply if the car is operated in the mode of compulsory idling. The control unit distinguishes this mode according to information "the frequency of rotation higher, than rotation frequency in the idling mode" and "is closed a butterfly valve".