Audi S4

since 2000 release

Repair and operation of the car



Audi S4
+ Introduction
+ Governing bodies and methods of safe operation
+ Current leaving and service
+ Engine
+ Cooling systems, heating and air conditioner
- Power supply systems, release and decrease in toxicity of the fulfilled gases
   + Power supply systems of petrol and diesel engines
   + System of injection of fuel of the petrol engine
   + System of injection of fuel of the diesel engine
   - Systems of release and decrease in toxicity of the fulfilled gases. Turbocompressor
      Removal and installation of system of release. Replacement of the central, additional muffler, trailer pipe
      Correction of laying of system of release / trailer pipe
      Systems of decrease in toxicity of release - the general information
      Catalytic converter
      Removal and installation of the catalytic converter and lambda probes
      Turbocompressor - the general information and precautionary measures
      The intercooler - the general information
+ Systems of electric equipment of the engine
+ Manual box of gear shifting
+ Automatic transmission
+ Coupling, power shafts and differential
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment





Systems of decrease in toxicity of release - the general information

Scheme of connection of vacuum lines. Engine of 1.8 l

1 — an EVAP system Adsorber
2 — From the fuel tank
3 — the Valve of management of EVAP adsorber purge
4 — the Control valve of depression in EVAP adsorber
5 — an air cleaner Casing
6 — the Turbocompressor
7 — the Valve of management of an additional admission of air
8 — the fuel pressure Regulator
9 — To the amplifier of brakes
10 — the Vacuum control valve
11 — the Vacuum amplifier
12 — To the pump of definition of leaks
13 — the Vacuum chamber
14 — the Vacuum T distributor
15 — the Vacuum control valve
16 — Em the valve of an additional admission of air

17 — Ventilation of a case
18 — the Vacuum control valve
19 — To the pump of definition of leaks
20 — the Vacuum control valve
21 — a turbocompressor Cooler
22 — the Module of control of the valve of a butterfly valve
23 — the Valve of recirculation of a turbocompressor
24 — the Inlet air duct
25 — Э / the motor of the pump of an additional admission of air
26 — the GUR Switch
27 — the Module of control of the valve of a butterfly valve
28 — the Valve of management of EVAP adsorber purge
29 — the Sensor of pressure of the forced air

Scheme of connection of vacuum lines. V6 engine

1 — the Amplifier of brakes
2 — the Vacuum control valve
3 — the Vacuum chamber (for the switching valve of an inlet air duct)
4 — the Vacuum control valve
5 — the throttle Case
6 — the Vacuum chamber
7 — an air cleaner Casing
8 — the Inlet air duct
9 — an EVAP system Adsorber
10 — the Valve of management of EVAP adsorber purge

11 — the fuel pressure Regulator
12 — the Vacuum T distributor to the EGR and K/V valve
13 — the Vacuum control valve
14 — the Vacuum T distributor to To/in
15 — TO K/B
16 — the Switching valve of an inlet air duct
17 — Э / the magnetic valve of management of EGR depression
18 — the Sound absorber
19 — the Control EGR valve

Petrol models

In power supply systems of all petrol models only unleaded gasoline has to be used. The control system of the engine functions so that to receive the maximum return from the engine at the minimum fuel consumption and toxicity of the fulfilled gases. The system of catching of vapors of fuel prevents hit them from the fuel tank in the atmosphere. The system of recirculation of the fulfilled gases is installed.

System of ventilation of a case

For elimination of leak of not burned down hydrocarbons in the atmosphere the engine is completely pressurized. The gases and vapors of oil which are formed in a case via the mesh filter get to the inlet pipeline and burn down in cylinders together with fuel.

Gases are removed from a case at the expense of pressure difference in a case and the inlet pipeline (pressure in a case is higher).

Catalytic converter

For decrease in number of harmful emissions in the atmosphere on all petrol models the three-functional catalytic converter is built in system of release. The control system of injection of fuel has feedback in which it is included a lambda probe. This sensor installed in system of release constantly informs the control unit on composition of the fulfilled gases. Depending on the obtained data, the control unit corrects quality of the mix given to combustion chambers and, thus, optimizes fuel combustion.

In a lambda probe the heating element which is switched on by the control unit via the special relay is built in. The working surface a lambda probe is sensitive to change of content of oxygen in gases. Depending on concentration of oxygen, the sensor sends signals of different tension. If mix of a pereobogashchen - the content of oxygen in the fulfilled gases very low, the sensor gives signals with low voltage. Tension increases in process of impoverishment of mix and increase in content of oxygen in gases. Most effectively the converter works at optimum quality of gas mixture (14.7 parts of air for 1 part of fuel). At optimum concentration of oxygen in the fulfilled gases there is a jump in tension on the sensor. This jump is a reference point for the control unit at correction of quality of mix.

About two sensors are installed. One - before, and the second — after the converter. It reaches more exact tracking of composition of the fulfilled gases.

System of recirculation of the fulfilled gases

The system of recirculation of the fulfilled gases allows to reduce the number of NOx in the fulfilled gases. For this purpose a small part of the fulfilled gases moves in the inlet pipeline via the special valve. The valve of system of recirculation is run by the control unit.

System of catching of vapors of fuel

Lines of system of catching of vapors of fuel. Engine of 1.8 l

1 — the Vacuum control valve
2 — the Valve of management of EVAP adsorber purge
3 — the Final pipeline from the valve of management of EVAP adsorber purge
4 — the Final pipeline from the gravitational valve
5 — an EVAP system Adsorber
6 — To the pump of definition of leaks
7 — the Casing of the air filter

8 — the Pump of definition of leaks
9 A vacuum hose of an inlet air duct to the pump of definition of leaks
10 — the Vacuum chamber
11 — the Control valve
12 — the Vacuum T distributor
13 — the Module of control of the valve of a butterfly valve

Lines of system of catching of vapors of fuel. V6 engine

1 — the Module of control of the activator of a butterfly valve
2 — the Valve of management of EVAP adsorber purge
3 — the Final pipeline from the valve of management of EVAP adsorber purge
4 — the Final pipeline from the gravitational valve
5 — an EVAP system Adsorber

6 — the Vacuum hose of an inlet air duct to the pump of definition of leaks
7 — the Casing of the air filter
8 — the Pump of definition of leaks
9 — the Vacuum hose of an inlet air duct to the module of control of the activator of a butterfly valve
10 — the Vacuum T connection

For decrease in emission in the atmosphere of not burned down hydrocarbons on all petrol models the system of catching of fuel is installed. The filling mouth of the fuel tank is hermetically closed by a cover, under the fuel tank the coal adsorber is established. In it the fuel vapors which are formed in a tank during the parking of the car gather and are stored there until on a signal of the control unit the adsorber purge does not begin. Then vapors of fuel begin to move via the purge valve in the inlet pipeline, there they mix up with working mix and further burn down usually in combustion chambers.

For ensuring normal operation of the engine on single turns and during warming up the control unit holds the valve closed. Thus hit of not burned down fuel in the converter (is prevented at the raised idling turns mix of a pereobogashchen). After warming up of the engine the valve begins to open and be closed, giving fuel vapors to an inlet path.

Diesel models

The control system of the engine functions so that to receive the maximum return from the engine at the minimum fuel consumption and toxicity of the fulfilled gases. For additional decrease in toxicity of gases on the car several additional systems are installed. System of ventilation of a case of a snizhayetutechka of gases in the atmosphere from the engine lubrication system. The catalytic converter reduces toxicity of the fulfilled gases. The system of recirculation of the fulfilled gases is installed.

System of the operated ventilation of a case

For elimination of leak of not burned down hydrocarbons in the atmosphere the engine is completely pressurized. The gases and vapors of oil which are formed in a case via the mesh filter get to the inlet pipeline and burn down in cylinders together with fuel.

Gases are removed from a case at the expense of pressure difference in a case and the inlet pipeline (pressure in a case is higher). On all diesel models the ventilation valve is installed. It is on a cover of a head of the block and operates a stream of gases from a case.

System of recirculation of the fulfilled gases

On all diesel models the system of recirculation of the fulfilled gases is also installed. This system allows to reduce the number of NO x in the fulfilled gases. For this purpose a small part of the fulfilled gases moves in the inlet pipeline via the special valve. The valve of system of recirculation is controlled by the control unit.