Mercedes S-Class W-220
since 1998 release
Repair and operation of the car
+ Mercedes-Benz cars of the class S (W220)
+ Operation manual
+ Routine maintenance
+ Cooling system and heating
- Power supply system and release
+ Power supply system and fuel injection
+ System of injection of fuel of the diesel engine. Turbocompressor
- Systems of release and decrease in toxicity of the fulfilled gases
Systems of decrease in toxicity of release - the general information
System of production of the fulfilled gases
+ Engine electric equipment
+ Automatic transmission
+ Power shafts
+ Brake system
+ Suspension bracket and steering
+ Onboard electric equipment
+ Schemes of electric equipment
The catalytic converter has the central ceramic part of a cellular design-3-covered with a carrier layer. On a layer of the carrier there are salts of precious metals operating as converters. The catalytic converter is fixed in the case-1-by means of the insulating basic layer-2-compensating at the same time thermal expansions of the catalytic converter.
To reduce harmful emissions by means of the catalytic converter, systems of injection has to dose precisely amount of the injectable fuel necessary for combustion. The sensor of oxygen is in a reception pipe in front of the catalytic converter and is washed by a stream of the fulfilled gases. The sensor of oxygen represents the electronic sensor measuring the content of oxygen in final gases and representing its type of fluctuations of tension. Information from the sensor of oxygen is transferred to the control unit of system of injection. The received value allows to regulate composition of air-petrol mix. On the one hand it is necessary as service conditions constantly change (idling, full gas), on the other hand, as optimum reburning of fuel in the catalyst happens only in this case if final gases contain enough fuel.
That in the catalyst there was a fuel reburning, it is necessary to have temperature of 300 - 800 °C. For this purpose the bigger content of fuel in mix, than is necessary for pure burning.
The used catalytic converters of petrol engines represent so-called three-functional devices. In adjustable process of transformation oxidation of carbon monoxide (SO) and hydrocarbon (NANOSECOND), and also reduction of concentration of nitrogen oxides (NOx) is carried out.
Security measures for an exception of damages of the catalytic converter
For an exception of damages of the sensor of oxygen and the catalytic converter it is necessary to fulfill the following requirements: