8.2. Catalytic converter
On all cars catalytic converters for reduction of amount of the harmful substances released into the atmosphere with the fulfilled gases are established.
Inlet and final cones with branch pipes and fixing flanges, and also the heatreflectors holding a ceramic covering are welded on the converter case made of stainless steel. All internal volume of the case is busy with a ceramic porous monolith – the catalyst fixed by rings or a grid from stainless steel. The catalyst represents the filter in which all internal and external surface of the time contacting to gases is covered with very thin layer of alloy which contains platinum, rhodium and palladium. The porous catalyst has big surface area, covered with this alloy from very expensive metals that generally and determines the high price of catalytic converters.
In converter there is a reaction as a result of which potentially dangerous hydrocarbon and carbon monoxide in the fulfilled gases turn into safe gases and water vapor.
On all models with converter a power supply system fuel – the closed type, that is on the basis of the signal from a lambda sensor established in system of release, the control unit constantly optimizes composition of fuel-air mix. Depending on the content of oxygen in the fulfilled gases the lambda sensor induces tension from 0,1 B (high content of oxygen, poor mix) to 0,9 B (low content of oxygen, rich mix). On the basis of these data the control unit of the engine changes time of opening of nozzles and a ratio of fuel in fuel-air mix. In order that there was a full combustion of gas mixture and in the fulfilled gases there were no harmful substances, 1 part of fuel has to fall on 14,7 weight parts of air.
Catalytic converter works effectively at a temperature of +300 … +800 °C.
Operation I cars with catalytic converter
Converter is a reliable and simple device which does not need service. In order that the term of its service was maximum, it is necessary to observe the following requirements.
Do not use ethylated gasoline in the car equipped with catalytic converter as lead will cover precious metals in a catalyst lattice, reducing their efficiency and as a result will put converter out of action.
Always you contain systems of ignition and food in good repair.
Do not operate the car with faulty system of ignition before malfunction elimination.
If during the operation of the engine the control lamp of engine management lights up, it is necessary to address as soon as possible on service station. If the control system of the engine is damaged, then except increase in fuel consumption and deterioration in dynamic characteristics of the engine catalytic converter can fail.
Do not launch the engine by means of towage.
Do not switch off ignition with a high frequency of rotation of the engine.
Do not use additive to fuel and engine oil as they may contain the substances capable to damage catalytic converter.
Do not use the car if from an exhaust pipe smoke of blue color is emitted.
After an engine stop the system of release a long time continues to radiate heat therefore it is necessary to avoid the parking of the car on a grass and dry leaves.
Remember that converter is fragile therefore avoid blows at removal it or other elements of system of release.
Service life of catalytic converter on well adjusted car makes 100–160 thousand km of a run of the car.