The catalytic converter has a central ceramic part of a honeycomb structure -3- coated with a carrier layer. On the carrier layer are noble metal salts that act as converters. The catalytic converter is fixed in the housing -1- by means of an insulating support layer -2-, which simultaneously compensates for the thermal expansion of the catalytic converter.
Gasoline engines
In order to reduce harmful emissions with a catalytic converter, injection systems must accurately dose the amount of injected fuel required for combustion. The oxygen sensor is located in the exhaust pipe before the catalytic converter and is washed by the exhaust gas flow. The oxygen sensor is an electronic sensor that measures the oxygen content in exhaust gases and presents it as a voltage fluctuation. Information from the oxygen sensor is transmitted to the injection system control unit. The obtained value allows you to adjust the composition of the air-gasoline mixture. On the one hand, this is necessary, since operating conditions are constantly changing (idle, full throttle), on the other hand, since the optimal post-combustion of the fuel in the catalytic converter occurs only in this case, if the exhaust gases contain a sufficient amount of fuel.
In order for the afterburning of fuel to occur in the catalytic converter, it is necessary to have a temperature of 300-800°C. This requires a higher fuel content in the mixture than for clean combustion.
The catalytic converter of a gasoline engine is a so-called three-function device. In a regulated conversion process, carbon monoxide is oxidized (SO) and hydrocarbon (NS), as well as a reduction in the concentration of nitrogen oxides (NOx).
Safety Precautions to Avoid Damage to the Catalytic Converter
To avoid damage to the oxygen sensor and catalytic converter, the following requirements must be met:
Gasoline engines
Be sure to use only unleaded gasoline.
Starting a warm gasoline engine by pushing or towing is allowed only in one attempt and at a distance of not more than 50 m. It is better to use a starter cable for this purpose. Unburned fuel, if ignited, can overheat the catalytic converter and destroy it.
Note. Starting vehicles with AT towing is not possible.
If it is difficult to start the engine, do not turn on the starter for too long. In this case, continuous fuel injection is performed. It is necessary to identify and eliminate the cause of the malfunction.
If malfunctions occur with the ignition system, when determining their nature, it is necessary to exclude fuel injection when the starter is turned on. To do this, turn off the fuel pump relay.
Never run out of fuel in a gas tank.
If misfiring occurs, do not increase the engine speed and repair the problem immediately.
Use only recommended spark plugs.
Do not perform spark tests with the spark plug connector disconnected.
It is not allowed to test the operation of the cylinder by disconnecting the ignition wire from its spark plug. In this case, unburned fuel enters the catalytic converter.
Gasoline and diesel engines
Do not park your vehicle over dry leaves or grass. The exhaust system around the catalytic converter is very hot and radiates heat even after the engine has stopped.
Do not apply any underbody protector to the exhaust system components.
It is not allowed to change the design of heat shields.
When filling the engine with oil, pay particular attention not to exceed the level indicated on the gauge as Max. Excess oil from incomplete combustion enters the catalytic converter and can damage its alloy metal coating or completely destroy the catalytic converter.