VW Passat B5

since 1996 release

Repair and operation of the car



Foltsvagen Passat B5
+ Maintenance instruction
+ 1. Maintenance
+ 2. Engines
+ 3. Cooling system
+ 4. Fuel system
- 5. Engine management
   5.2. Work of a control system of the engine
   5.3. Check of system of injection of fuel
   5.4. Sensors and executive mechanisms of a control system of the engine
   + 5.5. System of ignition
   + 5.6. Fuel highway and fuel nozzles
   5.7. Main malfunctions of a control system of the engine
+ 6. Exhaust system
+ 7. Transmission
+ 8. Running gear
+ 9. Steering
+ 10. Brake system
+ 11. Body
+ 12. Heating, ventilation
+ 13. Electric equipment






5.2. Work of a control system of the engine

GENERAL INFORMATION

Arrangement of the tape conductor (1) in the air stream measuring instrument


Elements of management of a butterfly valve

1 – control lever butterfly valve;
2 – idling switch;
3 – potentiometer of provision of a butterfly valve. The potentiometer reports to the control unit about the provision of a butterfly valve;
4 – servomotor of a butterfly valve;
5 – spring. At interruption in supply of tension the spring moves a butterfly valve to a basic position. In this situation the cable of an accelerator does not move a butterfly valve;
6 – potentiometer of provision of an executive element of a butterfly valve. The potentiometer of provision of an executive element of a butterfly valve transfers to the control unit data on the provision of an executive element of a butterfly valve.

The control system of the engine is a joint system of ignition and injection of fuel.

The fuel pump shipped in the fuel tank gives fuel to the fuel highway via the fuel filter. Fuel pressure in system is run by pressure regulator. The regulator allows excess fuel to come back to the fuel tank at excess of pressure in fuel system. The fuel highway is the tank for four fuel nozzles which make injection of fuel to inlet canals of cylinders of the engine. The consecutive system of injection of fuel at which nozzles inject fuel independently from each other is used. The control unit operates a fuel nozzle, changing the impulse width, that is an interval of time when the nozzle is open to provide richer or poorer fuel mix.

Air passes through the air filter, the measuring instrument of a stream of air and a butterfly valve to inlet channels of cylinders. The sensor of a stream of air represents the tape conductor which is energized (1) see rice. An arrangement of the tape conductor (1) in the air stream measuring instrument. Constant temperature of a tape is maintained by electric current which changes depending on the mass of the passing air. Current which needs to be given for maintenance of constant temperature of a tape is proportional to the mass of a stream of air. On the basis of information from the measuring instrument of a stream of air and other sensors the control unit regulates time and amount of injectable fuel according to the measured amount of air and speed of the engine. The longer the nozzle is open, the more fuel is injected.

Additional sensors transfer information to the control unit about temperature of cooling liquid, temperature of the air coming to the engine, and on models with the catalyst about the content of oxygen in exhaust gases.

The filter of absorbent carbon interferes with that harmful vapors of fuel got from the fuel tank into the atmosphere. Vapors of fuel collect in the container with absorbent carbon and during the operation of the engine are burned up in engine cylinders.

The memory device in the control unit distinguishes the appeared malfunction and writes down it. At failure of the important sensor the control unit switches to the emergency program in order that the engine continued to work, though with smaller efficiency.