The catalytic converter has a honeycomb ceramic core coated with a layer of noble metal salts that act as a converter. The catalytic converter is fixed in the housing by means of an insulating support layer, which simultaneously compensates for the thermal expansion of the catalytic converter.
The EFI system, in combination with a lambda probe, precisely regulates the amount of fuel injected so that the catalytic converter can reduce the amount of harmful substances in the exhaust gases. The lambda probe is located in the exhaust pipe before the catalytic converter and is washed by the exhaust gas stream. The lambda probe is an electrical measuring element that determines the oxygen concentration in the exhaust gases by changing the voltage and thus allows you to adjust the quality of the air-fuel mixture. Within a fraction of a second, the lambda probe can transmit the appropriate signals to the ECM, which allows you to continuously adjust the quality of the air-fuel mixture depending on changing operating conditions (idle, full throttle). In this way, optimum afterburning of the fuel in the catalytic converter is achieved.
So that in the catalytic converter at a temperature of 300 ÷ 800 degrees. afterburning of the fuel could occur, the air-fuel mixture should be slightly depleted of air.
Gasoline engines use a three-way catalytic converter to reduce carbon monoxide levels in exhaust gases (SO), hydrocarbon (NS), as well as nitrogen oxides (NO x).
On diesel engines, an oxidation catalytic converter is used, because. oxygen regulation is not required. Such a catalytic converter reduces the concentration of carbon monoxide and hydrocarbon contained in the exhaust gases. In addition, it reduces the smell of exhaust gases characteristic of diesel engines.
Catalytic converter and EGR system
Nitrogen oxide concentrations (NO x) in exhaust gases engines 1.0 and 1.2 l, as well as DOHC 1.4 and 1.6 l from 09.1994 release is maintained at a low level before the catalytic converter due to the presence of the EGR system.
EGR valve on engines DOHC 1.0 and 1.2 l located on the front side of the cylinder head; on other engines it is located on the exhaust manifold and controlled by the ECM. The task of EGR is to divert part of the exhaust gases into the combustion chambers of the engine in order to reduce the combustion temperature and, thereby, reduce the concentration of harmful substances.
Exhaust gas cleaning with additional air supply
The task of supplying additional air to engines DOHC 1.4 and 1.6 l from 09.1994 release is a decrease in the concentration of harmful substances in the exhaust gases of the engine when the engine warms up. The electric pump supplies fresh air to the engine exhaust ducts to ensure the afterburning of unburned compounds in the exhaust gases. This reduces the concentration of harmful hydrocarbons and carbon monoxide. In addition, the temperature of the exhaust gases rises, so that the catalytic converter warms up faster and oxygen control begins to take effect. The ECM turns off the supplemental air supply with oxygen control activated after about 1 ÷ 2 minutes. after cold start.
Safety measures for the operation of vehicles equipped with a catalytic converter
To avoid damage to the lambda probe and the catalytic converter, be sure to follow the following recommendations:
Gasoline engines
Use only unleaded gasoline. In case of mistaken refueling with leaded petrol, the catalytic converter and downpipe upstream of it must be replaced. Before installing new elements, at least two fills of unleaded gasoline must be used in the fuel tank.
Starting a warm gasoline engine by pushing or towing is best avoided. Use an auxiliary battery for this purpose. Unburned fuel, if ignited, can overheat and destroy the catalytic converter.
Avoid frequent consecutive cold starts. Otherwise, unburned fuel accumulates in the catalytic converter, which, when heated, burns out and, detonating, damages the catalytic converter.
If it is difficult to start the engine, do not turn on the starter for a long time, because. while continuously injecting fuel. Find and eliminate the cause of the malfunction.
If there are faults in the ignition, to identify the source of the fault, exclude fuel injection during starter engagement. To do this, disconnect the fuel pump relay located in the front passenger's footwell, in front of the A-pillar, behind the side trim.
Do not test spark plugs for sparks with their connector disconnected.
Do not disconnect the ignition from any cylinder, as while unburned fuel enters the catalytic converter.
If misfiring occurs, do not increase the engine speed and repair the problem immediately.
Gasoline and diesel engines
Do not park the vehicle over dry grass or foliage as the exhaust system heated in the area of the catalytic converter can cause a fire.
Make sure that the engine oil level does not exceed the MAX mark on the dipstick. Incomplete combustion can cause oil to enter the catalytic converter and cause it to malfunction.
Visitor comments