BMW 5 Series E39

since 1996-2001 release

Repair and operation of the car

+ Introduction
+ Maintenance instruction
+ Current leaving and service
+ Engine
+ Cooling systems, heating
- Power supply system and release
   + Power supply system
   + System of injection of the petrol engine
   + Power supply system of the diesel engine
   - System of production of the fulfilled gases
      Operation of the catalytic converter
      Security measures for cars with the catalytic converter
      Removal and installation of system of release
      Replacement of the main muffler
      Removal and installation of the sensor of oxygen
      Check of tightness of system of release
+ Engine electric equipment
+ Manual transmission
+ Automatic transmission
+ Coupling and power shafts
+ Brake system
+ Suspension bracket and steering
+ Body
+ Onboard electric equipment
+ Schemes of electric equipment
+ System of onboard diagnostics


Operation of the catalytic converter

All engines are equipped with the catalytic converter for purification of the fulfilled gases.

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.

Petrol engines

The electronically controlled system of injection in combination with the sensor of oxygen allows to dose precisely amount of injectable fuel that in turn reduces harmful emissions in the atmosphere. 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 result of measurement a 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 in view of continuous change of service conditions (idling, full gas), on the other hand, since optimum reburning of fuel in the catalytic converter happens only in this case if final gases contain enough gasoline.

That in the catalytic converter at a temperature of 300 - 800 °C there was a fuel reburning, in fuel mix it is necessary to have the bigger content of fuel, than for pure burning.

The used catalytic converter represents the so-called three-functional catalytic converter. It means that thanks to existence of process of regulation oxidation of carbon monoxide (SO) of and hydrocarbon (NANOSECOND), and also reduction of concentration of oxides of nitrogen (NOx) is carried out. Address an accompanying illustration.

Diesel engines

Cars with diesel engines are also equipped with the catalytic converter. However adjustment of composition of mix is impossible here. The catalytic converter reduces emission of carbon monoxide, harmful to the environment, and hydrocarbon to value considerably smaller, than at the petrol engine. Besides, catalytic converter reduces a smell of exhaust gases, characteristic of the diesel engine. Higher concentration of oxides of nitrogen at the diesel engine decreases by means of system of recirculation of the fulfilled gases.