Audi 100/A6

1990-1997 of release

Repair and car operation

Audi 100/A6
+ 1. Maintenance instruction
+ 2. Maintenance
+ 3. Engines
+ 3.2. Diesel engines
+ 3.3. Removal and partition of engines
+ 4. Cooling system
+ 5. Heating and ventilation
- 6. Fuel system
   + 6.1.2. Technical characteristics
   + 6.2. Multipoint system of injection of fuel
   - 6.3. System of injection of MPI/MPFI (6-cylinder engines)
      6.3.2. Technical characteristics
      6.3.3. Distinctions of systems of injection
      6.3.4. Sensors
      6.3.5. Idling regulation
      6.3.6. Removal and installation of klapanny nozzles
      6.3.7. Check of klapanny nozzles
      6.3.8. Oxygen sensor
   + 6.4. Power supply system of diesel engines
   6.5. Device of service of heating
   6.6. Diagnostics of malfunctions of system of heating
   6.7. Conditioner: not only "pluses", but also "minuses"
   6.8. Rules of service of the conditioner
+ 7. Exhaust system
+ 8. Systems of start, ignition
+ 9. Transmission
+ 10. Brake system
+ 11. Suspension brackets, steering
+ 12. Body
+ 13. Electric equipment
+ 14. Good advice


6.3.3. Distinctions of systems of injection


The system of injection of MPI has a switched inlet collector, two-piece whereas the MPFI system is equipped with not switched plastic inlet collector consisting of three parts. Besides, the MPFI system any more does not need a measuring instrument of a mass consumption of air.

Fuel is soaked up from a fuel tank by the electric pump and via the fuel filter moves to the batcher which is executed in the form of ring топливопровода, and then to klapanny nozzles. The pressure regulator on the end of the batcher supports to constants pressure of fuel in system.

Klapannye nozzles consistently inject fuel into an inlet collector in front of inlet valves. Injection is carried out not at the same time. It means that nozzles are disconnected, cope separately and inject fuel according to sequence of flashes in front of inlet valves of the engine. Thanks to a choice of the beginning of injection in relation to the moments of opening of inlet valves moshchnostny and ecological qualities of the engine can be regulated better. Acceleration performance of the engine Besides, improves.

Unlike system of injection of KE in MPI system instead of a measuring instrument of a volume expense the measuring instrument of a mass consumption of air is built in. Such measuring instrument has the following advantages: insignificant dimensions, automatic alignment of influence of temperature and height above sea level, lack of mobile details and consequently insignificant wear.
In a measuring instrument of a mass expense the thread heated up by an electric current is cooled with a stream of soaked-up air proceeding by. To maintain temperature of a hot thread of a constant, the current of heat changes according to proceeding amount of air. The control unit determines a loading mode of the engine by change of a current of heat and according to it regulates amount of injected fuel. To avoid distortion owing to pollution, after each switching off of the engine the thread is heated automatically.

The control unit according to a signal of a measuring instrument of a mass consumption of air and frequency of rotation of a cranked shaft regulates duration of injection, and thereby and amount of injected fuel. At longer opening of a klapanny nozzle of fuel it is injected more. Additional sensors and converters in any road situation care of the correct otmerivaniye of amount of injected fuel.