Audi A3

Since 1997 of release

Repair and car operation


Audi A3
+ The maintenance instruction
+ Current leaving and service
+ The engine
+ Systems of cooling, heating
- The power supply system and release of the fulfilled gases
   + The power supply system
   + System of injection of fuel
   + System of injection of the diesel engine
   - System of release of the fulfilled gases
      Work каталитического the converter
      Security measures for an exception of damages каталитического the converter
      Removal and installation of system of release
      Checking of system of release
      Replacement of the central/additional muffler
      Check of system of release on tightness
      Replacement of the gauge of oxygen
+ Engine electric equipment
+ Manual box of a gear change
+ Automatic transmission and models with a full drive
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Electroschemes

Work каталитического the converter
THE GENERAL DATA

All engines are equipped one or several catalyticи by converters for clearing of exhaust gases.
The Katalitichesky converter has the central ceramic part of a cellular design–3 covered with a layer of the carrier. On a carrier layer there are the salts of precious metals operating as converters. The Katalitichesky converter is fixed in the case by-1 means изоляционного the basic layer–2 compensating simultaneously thermal expansions каталитического of the converter.

The Katalitichesky converter
1 case
2 consolidation
 3 honeycomb каталитического the converter

Petrol engines

To reduce with the help каталитического the converter harmful emissions, injection systems should dose out precisely quantity of the injected fuel necessary for combustion. The oxygen gauge is in a reception pipe before catalytic the converter and is washed by a stream of the fulfilled gases. The oxygen gauge represents the electronic gauge measuring the maintenance of oxygen in final gases and representing its kind of fluctuations of pressure. The information from the oxygen gauge is transferred to the block of management of system of injection. The received value allows to regulate structure of an air-petrol mix. On the one hand it is necessary, as service conditions (the idling, full gas), on the other hand, constantly change as optimum reburning of fuel in the catalyst occurs only in this case if in final gases fuel enough contains.

That in the catalyst there was a fuel reburning, it is necessary to have temperature 300 – 800°С. For this purpose it is necessary большее the fuel maintenance in a mix, than for pure burning.

Applied каталитические converters of petrol engines represent so-called three-functional devices. In adjustable process of transformation oxidation oxide carbon (WITH) and hydrocarbon (NANOSECOND), and also concentration reduction оксидов nitrogen (NOx) is carried out.

Gases on an input каталитического the converter and products on its exit

The Katalitichesky converter and system recycling the fulfilled gases of the diesel engine

The fulfilled gases of the diesel engine also are cleared in каталитическом the converter. Thus it is a question about noncontrollable oxidising каталитическом the converter. Such каталитический the converter transforms containing in the fulfilled gases оксиды carbon and hydrocarbonic connections in СО2 and Н2О.

Concentration decrease in the fulfilled gases of the diesel engine оксидов nitrogen (NOx) is reached thanks to presence of additional system of regeneration of the fulfilled gases (system EGR).

On a final collector of the engine the system valve recycling, operated vacuum is located. Its problem is the direction of a part of the fulfilled gases in chambers of combustion of the engine that promotes decrease in temperature of the fulfilled gases and by that to decrease in concentration of harmful substances.


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