Audi 80/Avant (B4)

Since 1991-1995 of release

Repair and car operation



Audi 80/Avant
+ The description
+ Engines
+ System of release of the fulfilled gases
+ Cooling system
+ Fuel tank and the fuel pump
- The air filter and воздухозаборные channels
   Removal of a replaceable element of the air filter
   Purge of a replaceable element of the air filter
   Replacement of a replaceable element of the air filter
   Heating of inlet air
   Heating of an inlet collector
   Inlet collector with changeable length of a path
+ Injection system
+ Coupling
+ Transmission and transmission
+ Suspension bracket and steering
+ Brake system
+ Antiblocking system of brakes
+ Wheels and tyres
+ Kuzovnaja electrosystem
+ Ignition system
+ Illumination
+ Signalling devices
+ Devices and auxiliary devices
+ Heating and ventilation
+ Body elements
+ Search of malfunctions
+ Specifications



Heating of inlet air

The device of automatic heating of inlet air is on the entrance party of the case of the air filter. Its problem – to maintain the necessary temperature of air which is soaked up by the engine.

It is important for the following reason: in cold weather the gas mixture is formed better if inlet air moves warmed up. However at higher external temperatures giving of preliminary warmed-up air is not necessary to the engine: the same quantity of warm air has больший volume, than cold. As the engine can let in only certain quantity of air at the included preliminary heating of inlet air it receives less air and the gas mixture becomes reenriched, the expense raises. So the preliminary heating is necessary for uniform work of the engine only at low temperatures.

Work principle

Models with 4-cylinder engines: small engines have a vacuum regulation of preliminary heating of inlet air. Depression gathers at the engine for throttle заслонкой and operates on мембранный the mechanism of a vacuum regulator of an advancing of ignition which in turn opens the valve of heating of inlet air in an inlet branch pipe of the air filter.

In the vacuum pipeline conducting to the valve of the warmed-up air, in the case of the air filter the temperature regulator interrupting free passage in this sleeve if the temperature of external air has reached temperatures from +35 to +45С (Mono-Motronic) or +20 to +30С (Digifant) is in addition included.

Malfunctions

  • Models with 5 and 6-cylinder engines: at these engines the valve of heating of inlet air copes through the thermostat providing full access of warm air at–20C. At the raising temperature the valve slowly is closed, until then while it at +5C will not block completely access of warm air.
    If the heating of inlet air does not function how should, it is fraught with operation disturbances. In the winter:
  • Bad work of the engine after start during the so-called period of warming up.
  • The engine works roughly, with faults.
    In a warm season:
  • Insufficient capacity, it is impossible to develop the maximum speed.
  • The raised expense of fuel.

Check of heating of inlet air

Models with 4-cylinder engines

 PERFORMANCE ORDER

  1. The temperature regulator is in the case of the air filter. Its tips of sleeves are accessible at the engine with system of injection Mono-Motronic from the bottom party of the air filter.
  2. To disconnect a sleeve from a brass tip, or a tip with a mark.
  3. Mouth strongly to involve air from a sleeve: заслонка hot air it should open or be closed with a sound.
  4. If it has not occurred: to check up the valve on ease of a course, a sleeve and мембранный the mechanism of a vacuum regulator of an advancing of ignition on tightness.
  5. Then to check up a temperature regulator. At check air temperature should be more low +20C.
  6. To remove a sleeve tip to air заслонке at a temperature regulator or at the valve of hot air.
  7. To remove a sleeve tip to the engine on the block of preparation of a gas mixture or on the case of throttle knot.
  8. Mouth strongly to involve air from a sleeve: the sleeve should be "passed".
  9. The hair dryer to warm up a temperature regulator to more 45C. Again strongly to involve air from a sleeve: now it should be closed.
  10. Otherwise to replace a temperature regulator.

Models with 5 and 6-cylinder engines

 PERFORMANCE ORDER

  1. To remove an air inlet sleeve behind a headlight cap
  2. To look in a sleeve branch pipe, if necessary to illuminate a small lamp.
  3. Depending on an ambient temperature (the previous section see) air заслонка should close access of cold or hot air.

After removal of a sleeve of giving of air at the 5-cylinder engine the valve (2) preliminary heatings of inlet air is visible. At once near to it the thermoelement (1) setting it in motion is located. The position (3) shows a sleeve of the warmed-up air, the leader to a final collector.

At the left: on an illustration the case of the air filter removed and postponed in a motor compartment is shown. The membrannyj mechanism of a vacuum regulator of an advancing of ignition with заслонкой hot air (2) will turn out from the filter case, the vacuum sleeve (arrow) is still connected:

1 – an inlet branch pipe of cold air;
3 – a sleeve of warm air.

On the right: the temperature regulator (2) heatings of inlet air is located at the engine by capacity of 85 kw in a cover of the case of the air filter. The position (1) designates the vacuum sleeve approaching from the engine.