The catalytic converter of exhaust gases has a stainless steel housing, to which the inlet and outlet cones with pipes and fastening flanges, as well as heat reflectors holding the ceramic lining, are welded. The entire internal volume of the housing is filled with a ceramic porous monolith or a wire mesh made of heat-resistant stainless steel, which are fixed with rings. The structure of the monolith is a conventional filter, the internal and external surface of the pores of which, in contact with gases, are covered with a very thin molecular layer of an alloy of an active catalytic substance containing platinum, rhodium and palladium. The porosity of the monolith has a large surface area covered with this alloy of very expensive metals, which mainly determines the high price of the catalytic converter.
The catalytic converter causes a reaction that converts hazardous hydrocarbons and carbon monoxide in the exhaust gases into harmless gases and water vapor.
On vehicles with a catalytic converter, the fuel supply system is closed-loop, i.e. based on the signal from the lambda sensor installed in the exhaust system, the control unit constantly optimizes the composition of the fuel-air mixture. Depending on the oxygen content in the exhaust gases, the lambda sensor induces a voltage of 0.1 V (high oxygen, lean mixture) up to 0.9 V (low oxygen, rich mixture). Based on this data, the engine control unit changes the opening time of the fuel injectors and changes the fuel ratio in the fuel-air mixture. The stoichiometric ratio of the fuel mixture, at which its complete combustion occurs and there are no harmful substances in the exhaust gases, is 14.7 parts by weight of air to 1 part of fuel.
The catalytic converter operates effectively at temperatures of +300... +800°C.
Operation of vehicles with a catalytic converter
The catalytic converter is a reliable and simple device that does not require any maintenance, but there are some facts that the owner should know to ensure its maximum service life.
Do not use leaded gasoline in a vehicle equipped with a catalytic converter, as the lead will coat the precious metals in the converter grid, reducing the efficiency of their conversion and eventually causing damage to the converter.
Always keep the ignition and fuel system in good order.
If misfiring is observed while the engine is running, do not operate the vehicle until the problem is corrected.
If the engine control indicator lamp lights up while the engine is running, you should contact a service station as soon as possible. If there is damage to the engine control, then in addition to increased fuel consumption and reduced engine performance, the catalytic converter may fail.
Do not tow start the engine.
Do not turn off the ignition at high engine speeds.
Do not use fuel or motor oil additives as the additives may contain substances that can damage the catalytic converter.
Do not operate the vehicle if blue smoke is visible from the exhaust pipe.
After the engine has stopped, the exhaust system continues to emit a significant amount of heat for a long time, so you should avoid parking your car on grass and dry leaves.
Remember that the catalytic converter is fragile, so avoid impacts when removing the catalytic converter or exhaust system.
A catalytic converter used on a well-adjusted vehicle should last more than 100,000 km.
