Mercedes W124

since 1985-1995 of release

Repair and car operation



W124 Mercedes
+ Governing bodies and control devices
+ MAINTENANCE
+ 2. Maintenance (diesel engines)
+ ENGINE
+ 4. Repair of 6-cylinder petrol SOHC engines
+ 5. Repair of 6-cylinder petrol DOHC engines
+ 6. Repair of the diesel engine established in the car
+ 7. Major maintenance of engines
+ COOLING SYSTEM
+ FUEL SYSTEM
+ 10. System of injection of BOSCH CIS-E fuel (KE-JETRONIC)
+ 11. System of injection of BOSCH HFM fuel
+ 12. Fuel system of diesel engines
- 13. Fuel system of diesel engines
   13.2. General information
   13.3. Catching system паров fuels
   13.4. System of ventilation of a case
   13.5. Final collector
   13.6. System of repeated burning of exhaust gases (EGR)
   13.7. Turbonagnetatel
   13.8. Exhaust system
   13.9. Katalichesky converter
+ SYSTEMS OF START, IGNITION
+ 15. System of ignition of 4-cylinder petrol engines
+ 16. System of ignition of four-cylinder petrol engines
+ PRESTARTING HEATING
+ TRANSMISSION
+ 19. Mechanical transmission
+ 20. Automatic transmission
+ POWER SHAFTS
+ BRAKE SYSTEM
+ SUSPENSION BRACKET
+ BODY
+ ELECTRIC EQUIPMENT
+ CHECK OF MALFUNCTIONS






13.2. General information

System of fall of toxicity of exhaust gases

On all models with petrol engines it is possible to apply unleaded gasoline. Control systems of the engine choose an optimum mode for a combination of dynamic characteristics of the car, the minimum consumption of fuel and reduction of harmful substances in exhaust gases.

To reduce atmosphere pollution from short burned hydrocarbons and evaporating gases and to create optimum conditions for operation of the engine, the following systems of fall of toxicity of exhaust gases are applied:

– system of ventilation of the case, reducing emission of polluting substances from system of greasing of the engine (it is established on all models);
– the catalyst, neutralized harmful substances in exhaust gases (it is established on the majority of models);
– catching system паров the fuels, reducing an exit of gaseous hydrocarbons and a fuel tank (it is established on all models).

Besides, on some models the system of repeated burning of exhaust gases (EGR) and system of compulsory forcing of air which reduces amount of not burned down fuel in exhaust gases is established.

All diesel engines are also equipped with system of ventilation of a case. Also on some models the catalyst and system of repeated burning of exhaust gases (EGR) is established.

System of ventilation of a case

To reduce emission of not burned hydrocarbons from a case in the atmosphere, at the tight engine karterny gases and oil steam are delayed from a case to the highway of supply of air in the engine and дожигаются by the engine.

Catalytic converter on models with бензиновы ми engines

For reduction of emissions of harmful substances with exhaust gases on the majority of models establish каталитичес a cue the converter. On all models with the catalytic converter a power supply system fuel of the closed type, i.e. on the basis of a signal from a Lambda sensor, established in a reception exhaust pipe, the ECU block constantly optimizes structure fuel - an air mix.

For normal work of Lyambda-datchi it has a heater which copes the ECU block and via the relay the Lambda sensor maintains constant temperature the Lambda sensor. Depending on the content of oxygen in exhaust gases the Lambda sensor induces tension from 0,1 In (the high content of oxygen, a poor mix) to 0,9 In (the low content of the oxygen, a rich mix). On the basis of these data the control unit the engine changes time of opening of fuel nozzles and changes a fuel ratio in a fuel mix. Stekhiometri a chesky ratio of a fuel mix at which there is its complete combustion and in the exhaust there are no harmful substances, is 14,7 weight parts of air on 1 part of fuel.

Additional supply of air in an exhaust system reduces emission of harmful substances and WITH. The air pump put in action from an auxiliary driving belt, pumps up air under pressure in a final collector where fresh air mixes up with short burned-down particles of fuel. Fresh air makes final oxidation of not burned down substances, turning them into carbon dioxide and water vapor.

For reduction of emission of an oxide of nitrogen in the atmosphere together with exhaust gases the part of exhaust gases via the EGR valve arrives in an inlet collector and is repeatedly burned.

Catalytic нейтрализа Torahs of exhaust gases on models with diesel engines

On models with diesel engines in an exhaust system establish oxidizing catalyst which will neutralize gaseous hydrocarbons and WITH in exhaust gases. On some models in an exhaust system the special filter which catches firm particles of hydrocarbons is established.

On some models the system of repeated burning is established is fulfilled ny gases. At work of this system for reduction of emission of an oxide of nitrogen in the atmosphere together with exhaust gases, the part of exhaust gases via the valve of system of repeated burning of exhaust gases arrives in an inlet collector and is repeatedly burned. The electropneumatic system of repeated burning of exhaust gases copes the ECU block.

Catching system паров fuels on models with petrol engines

For a hit exception паров fuels in the atmosphere the catching system паров fuels with the canister filled with charcoal is used. Pairs of fuel from a fuel tank and the poplavkovy chamber of the carburetor gather in the canister with the charcoal, located under the left wing. Pairs of fuel from the canister with charcoal at the expense of a difference of pressure are delayed in the case of a throttle and burned in engine cylinders. Procrastination process паров fuels from the canister with charcoal via the valve of cleaning is regulated by the thermovalve which opens the cleaning valve only after engine warming up to a certain temperature. It is necessary to exclude mix reenrichment at operation of the cold engine.

Exhaust system

The exhaust system consists of a final collector, a reception exhaust pipe, exhaust silencers and connecting pipes, the catalytic converter and arms and rubber suspension brackets.

Turbonagnetatel established on model with diesel engines, is cooled with oil and has regulating valve of pressure. At failure of the regulating valve works the valve of protection of the engine from an overload and via the executive mechanism reduces supply of fuel by the fuel pump of a high pressure to level of the diesel engine without a turbo-supercharging.