Audi 80/Avant (B4)

since 1991-1995 release

Repair and operation of the car

Audi 80/Avant
+ Technical specification
+ Engines
+ 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 of Mono-Motronic
   + System of injection of Digifant
   - System of injection of KE-III-Jetronic
      Basic elements
      Operating procedure
      Lambda regulation
      Malfunctions and independent diagnostics
      Independent repair
      Visual check
      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
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Anti-blocking system of brakes
+ Wheels and tires
+ Body electrical system
+ System of ignition
+ Lighting
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ body Elements
+ Search of malfunctions
+ Specifications

Lambda regulation

Plug connections to a lambda probe:

1 – heating lambda probe;
2 – signal lambda probe.

Catalytic converter can correctly work only if the coefficient of excess of air l is perhaps closer to 1 that corresponds to a fuel/air 14,7/1 ratio. In order that it was carried out in practice, the system of injection of KE-III-Jetronic is supplied so-called a lambda regulation.

Thus the lambda probe measures amount of oxygen in the fulfilled gases – comparative size for composition of mix of fuel/air. If the indicator deviates from ideal, the control unit gives an assignment to pressure regulator in the proofreader of composition of gas mixture immediately to change composition of mix. Regulation works (any kolebatelno because only in this case catalytic converter copes with almost full transformation of harmful substances) in the range from l = 0,8 to l = 1,2.

The lambda probe transmits a signal only after temperatures exceeding 350 °C therefore it electrically is warmed (in addition to temperature of the fulfilled gases). Until it does not reach the working temperature, the system is lagged behind unregulated and is guided by the set average coefficient. In the same way regulation happens if enrichment of gas mixture in the conditions of full loading is activated.