Mercedes C-Class

W203 since 2000 of release

Repair and operation of the car

Mercedes-Benz
+ Mercedes-Benz cars of class C (W-203)
+ Operation manual
+ Routine maintenance
+ Engine
+ Cooling system and heating
- Power supply system and release
   + Power supply system of the petrol and diesel engine
   + System of injection of fuel of the petrol engine
   + System of injection of fuel of the diesel engine. Turbocompressor
   - Systems of release and decrease in toxicity of the fulfilled gases. Turbocompressor
      System of production of the fulfilled gases - general information
      Removal, installation of system of release and check of tightness
      Systems of decrease in toxicity of release - the general information
      Catalytic converter
      Turbocompressor - the general information, removal and installation
      The compressor of the blown air with the belt drive
      The intercooler - the general information
+ Engine electric equipment
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment

Systems of decrease in toxicity of release - the general information

Scheme of an arrangement of components of systems of decrease in toxicity. C240 and C320 models


1 — the Valve of management of an adsorber purge 2 — the Valve of a cut-off of a coal adsorber 3 — the Coal adsorber	4 — pressure Sensor in the fuel tank 5 — the Fuel pump

The scheme of connection of vacuum lines (model with the engine 111 equipped with the air compressor)


1 — the Actuation mechanism of the gate of recirculation 2 — the Compressor of the given air 3 — the Intermediate cooler (Intercooler) 4 — the Control valve of admixture of secondary air 5 — the Valve switch of the air pump 6 — the Vacuum control valve 7 — the Valve of a cut-off of secondary air 8 — pressure Sensor	9 — the Control valve (a coal adsorber) 10 — the Valve of management of a purge of a coal adsorber 11 — the Valve of a cut-off of a coal adsorber 12 — the Coal adsorber 13 — the Ventilating valve 14 — the Valve of dumping of pressure (ORVR) 15 — the Fuel tank 16 — the Jellied mouth of the fuel tank with the socket of system of catching of fuel evaporations

The scheme of connection of vacuum lines (model with the V6 engine)


1 — Transdyuser of EGR valve pressure 2 — the EGR Valve 3 — the Vacuum control valve 4 — the Valve switch of geometry of the inlet pipeline 5 — the Block of switching of the inlet pipeline 6 — the Valve of a cut-off of secondary air with the built-in control valve 7 — the Electric air pump	9 — pressure Sensor 10 — To other consumers of depression 12 — the Jellied mouth of the fuel tank with the socket of system of catching of fuel evaporations 13 — the Valve of a cut-off of a coal adsorber 14 — the Coal adsorber 15 — the Fuel tank

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 which switched on the oxygen sensor. 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 composition 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

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 filter purge does not begin. Then vapors of fuel begin to move via the purge valve(s) 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. The system of ventilation of a case reduces leak 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 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 controlled by the control unit.