Mercedes S-class W202

1993-2000 of release

Repair and car operation

Mercedes W202
+ 1.2. The general data
+ 2. Maintenance service
+ 3. Engines
+ 4. Greasing system
+ 5. Cooling system
+ 6. Heating, ventilation
+ 7. Ignition system
- 8. Fuel system
   + 8.1.1. Introduction
   + 8.2. System of injection of petrol engines
   + 8.3. System of injection and a food of diesel engines
   - 8.4. System of release of the fulfilled gases
      8.4.2. The basic and average mufflers
      8.4.3. Cars with the catalyst
      8.4.4. The device of neutralisation of the fulfilled gases of the diesel car
      8.4.5. Three in one – or how to save the catalyst
+ 9. Transmission
+ 10. A running gear
+ 11. A steering
+ 12. Brake system
+ 13. A body
+ 14. An electric equipment
+ 14.2. Electroschemes

8.4.3. Cars with the catalyst

Engines which устанавлены on the S-class are serially equipped by the adjustable catalyst. This catalyst demands, that the petrol engine was essentially maintained on неэтилированном fuel. Besides, cars with the adjustable catalyst should have an adjustable carburettor.

The adjustable carburettor is understood as the carburettor or system of injection of fuel at which the relation of fuel to air can constantly change depending on modes of movement and from the oxygen maintenance in the fulfilled gases. It cannot be carried out at use of the traditional carburettor as it is not equipped by the corresponding block of management. For this reason come back or to the carburettor regulated by means of electronics, or to system of injection of fuel.

The carburettor receives commands of management from the oxygen gauge which is established in the final pipeline in front of the catalyst or in a final collector is here again washed by a stream of final gases. The oxygen gauge is a sensitive element and signals about the residual maintenance of oxygen in the fulfilled gases by means of fluctuation of pressure and promotes conclusion delivery about structure топливовоздушной to a mix. In fractions of a second the oxygen gauge can transmit corresponding electric signals on the block of management of the carburettor and, thanks to it, the parity fuel-air constantly changes. It, on the one hand, is required, as in any case service conditions (the idling, full opening throttle заслонки), and, on the other hand, as well constantly change because only in this case on the catalyst there is a reburning as in the fulfilled gases of the engine still there is a sufficient share of gasoline.

Hence, that at temperature from 300 to 800 With on the catalyst in general there could be a reburning, the gas mixture should have больший fuel percent, than it it would be required for pure combustion. Thus, at catalyst application it is necessary to reckon with the raised expense of fuel reaching from one to five percent.

The catalyst is established under the basis of a body of the car instead of the additional muffler. The catalyst consists of the porous ceramic monolith covered with a layer of platinum or rhodium. For installation of a ceramic body sensitive to pushes the elastic and heat resisting metal fabric is used.

In this case it is a question of the so-called three-functional catalyst. It means that on this catalyst, on the basis of the data received from the oxygen gauge, oxidation окиси carbon (WITH) and hydrocarbons (NANOSECOND) to СО2 and Н2О, and also simultaneous restoration of oxides of nitrogen (NOх) to nitrogen is spent.

Care of the cars equipped with the catalyst

To avoid damage of the oxygen gauge and the catalyst, necessarily follow following instructions:

 – Essentially fill the car only неэтилированным with gasoline. If you have by mistake refuelled этилированным gasoline it is necessary to replace an exhaust pipe in front of the catalyst, and also the catalyst. Before installation of new details of the catalyst it is necessary выездить not less than two fuel tanks filled неэтилированным with gasoline. Start of the engine by means of pushing or towage can be made only in that case when the engine is started at once. Not burnt down fuel at ignition can lead to a catalyst overheat and by that to its destruction. Use start of a starter from the auxiliary storage battery.

 – It is necessary to avoid frequent start-up of the cold engine following one after another. In this case on the catalyst not burnt down fuel which at the subsequent heating suddenly ignites gathers, and thus to the catalyst harm is done.

 – At occurrence of difficulties at engine start it is not necessary to press long time a starter. During start fuel is continuously injected. Define and eliminate a cause of defect.

 – Apply only the spark plugs of firm Mercedes resolved to operation.

 – Do not inspect presence of the spark category on tips of wires to spark plugs.

 – If faults искрообразования are observed, avoid high frequency of rotation of a shaft of the engine and urgently eliminate defect.

 – Do not stop the car over the dried up foliage or a grass. The system of release of the fulfilled gases becomes very hot in a zone of the catalyst and radiates residual heat even after an engine stop.

 – At pouring or доливке some engine oil especially pay attention to that the maximum mark in the index of level of oil has not been exceeded at all. Otherwise superfluous oil because of incomplete combustion gets on the catalyst and can damage precious metal or completely destroy the catalyst.