Logo carsalmanac.com

Catalyst: what is it? Why do you need a catalytic converter in your car?

Table of contents:

Catalyst: what is it? Why do you need a catalytic converter in your car?
Catalyst: what is it? Why do you need a catalytic converter in your car?

There is one detail in modern cars that has been the cause of very hot battles for motorists for many years. But in these disputes it is difficult to understand the arguments of each side. One part of motorists is "for" and the other is "against". This part is the catalytic converter. Why do we need a catalyst, what is it that is so important in the design of a car, why are they always arguing about it? Let's try to figure it out.

Catalytic Converter

This part has a simple design, but the role it plays in the car is very large and serious. The operation of any internal combustion engine is accompanied by the release of many different and very harmful substances (all these substances and toxic gases are released directly into the atmosphere through the vehicle's exhaust tract). The converter allows you to significantly reduce the level of toxicity of emissions, thereby improving the environmental situation.

So, with the help of special chemical reactions, especially toxic substances that do not have the best effect on the state of the atmosphere are converted into less toxic gases, which are then removed throughexhaust pipe.

photo catalyst
photo catalyst

In the exhaust system, in addition to the converter, oxygen sensors also work. They control the quality of the combustible mixture and affect the operation of the catalytic converter. You can find this device in the exhaust path between the muffler and the engine. The device is additionally protected by a metal screen, because the device heats up during operation. See what the catalyst looks like - a photo of it is posted below.

History of Creation

In the 60s, the governments of all developed countries of the world paid attention to the level of ecology and attended to the amount of emissions from the exhaust pipes of numerous cars. And I must say that the law did not regulate emission levels at that time.

In 1970, the very first standards were adopted, which were brought to the attention of the management of automobile concerns. These standards provided a list of guidelines on the content and quantity of especially harmful substances in toxic exhaust gases.

catalytic converter repair
catalytic converter repair

This standard indicated that a catalyst must be used in new cars, that such a device would significantly reduce the volume of carbon monoxide and hydrocarbon combustion products.

Since 1975, all cars produced have been equipped with catalysts. This part has become mandatory.

Design and principle of operation

This device is often installed after the engine outlet pipe, or it can be mounted directly on the exhaust manifold flange.

The device consists ofspecial carrier unit, metal case and thermal insulation materials.

The carrier consists of many cells, similar to a honeycomb. It does almost all the work in the device. These honeycombs have a special coating - the working composition. Interestingly, the part does not start working immediately, but only after the temperature in the exhaust tract rises to 200-300 degrees.

The converter burns out carbon monoxide, which is contained in the combustion products of fuel, as well as hydrocarbons. There are also other substances that neutralize the catalyst. What are these substances? This is NOx. The gas is highly toxic and harmful. It destroys human mucous membranes.

Cells-neutralizers are coated with a very thin film based on a unique platinum-iridium alloy. Those residues of toxic substances that did not burn out in the engine burn out instantly when touching the hot surface of small cells. For this process, the catalyst takes the rest of the oxygen that remains in the already exhausted toxic gases. As a result of the work of this part, non-toxic substances come out of the exhaust pipe.


Catalyst cartridges can be made of ceramic materials or metal. Among motorists, ceramic products are more common and popular. They perfectly withstand high temperatures, and they are not affected by corrosion. Among the advantages is the low price of such a catalyst (experts know that such a substance as ceramics has a low cost).

ford catalyst
ford catalyst

I haveceramic catalyst and cons. This is his fragility. The part is absolutely unstable to all sorts of mechanical damage, and since the device is located under the bottom of the car, there is a considerable probability that the device will meet a curb, a stone, or anything. Then the part will break. Metal analogues are much stronger, but their price is very high due to the platinum alloy. For example, a VAZ catalyst cannot be repaired in the event of a breakdown, and many do not buy a new one because of the high cost.

Catalysts on different car brands

Cars depending on their manufacturer can vary significantly. The same applies to neutralizers. They also vary from model to model. We will look at the most popular car brands.


The catalyst on VAZs is no different. They are all metal, often fail due to various damages. You can find the device in the car under the bottom, near the engine exhaust pipe. Often, in the event of failure, repair of the catalyst is impossible.


Unlike domestic automakers, Ford took care of the drivers. So, the device for neutralizing toxic gases in cars of this brand is made on the basis of ceramics.

To regulate the volume of oxygen, for the qualitative passage of a chemical reaction, the device uses a lambda probe, which is integrated into the ECU.

So, the "Focus" catalyst consists of one catalytic manifold and two sensors. Two collectors work with powerful engines, as well as 4 sensors. The latter can be found both before and after the device. The operation of the neutralizer can be controlled from the dashboard.

The device is designed for 120 thousand kilometers. If you use low-quality fuel with the engine, this part can fail much faster. In the event of a failure, it is impossible to repair the Ford catalyst. In this case, only the replacement is performed.

Checking the functionality is very simple, and it is also easy to understand that a replacement is needed. With a non-working catalyst, power characteristics drop significantly. To check the operation of the device, it is necessary to measure the harmful substances in the exhaust of the machine. If the filters are clogged, then the level of harmful toxins will go off scale.

You can also check the performance by removing the sensor installed before the converter.

chevrolet catalyst
chevrolet catalyst

Then, using a special adapter, you need to connect a pressure gauge and take pressure measurements at various engine loads. Even if the device is out of order, it is not possible to repair the catalyst.

If the Ford catalyst is clogged, in this case, the old device is removed, and a new one with increased rates is installed in its place. You can also install a flame arrester or a universal converter instead of a catalyst.

Toyota catalyst

"Toyota" in this matter also does not differ in anything remarkable. These are the same honeycombs coated with gold or a platinum-iridium alloy. There are three such devices in new cars of this brand - they are connected to each other.with a friend in series. Each of them is designed to clean gases from one specific type of harmful substances.

Correct operation of the catalyst

In order for the device to protect the ecological situation as long as possible, it is necessary to use it correctly. So, the first and most important recommendation that will extend the life of the equipment is high-quality fuel from well-known and popular brands. Poor-quality fuel may contain substances that can easily destroy honeycomb coating. Particularly bad effect on the catalyst ("Kalina" is no exception) is a metal such as tetralead. This substance has long been banned in many developed countries.

You must also remember that the converter works at very high temperatures, so you should not park the car where flammable objects, leaves, paper or something else are lying around.

The driver, if he wants to save the catalyst, should not often turn on the starter if the car does not start.

catalyst on vases
catalyst on vases

Better pause. Also, do not rotate the crankshaft while turning off the spark plugs. You should also not start the engine with a tug.

How to understand that it is broken

If, for example, a catalyst is installed on a car (including a Chevrolet Aveo) and you need to understand whether it works or not, then there are several ways to do this.

When the car is running normally, then under all modes, the lamp on the dashboard indicating the problem of the catalyst will not light up.

viburnum catalyst
viburnum catalyst

If the part is in a semi-working state, then there is a lack of engine thrust at high speeds. In the morning the car starts worse. Also, the car loses momentum and increases fuel consumption. These are all signals that the part needs to be replaced.

DIY Repair

At numerous service stations, motorists are told that the repair of these devices is impossible. In fact, it is. However, if the part is clogged, you can try to rinse it. If there are several neutralizers in the car, then the first one is removed and the second one is washed. You can see such a catalyst - its photo is below.

what is a catalyst
what is a catalyst

Flushing is recommended with a mixture for cleaning carburetors. If the result is too much deposits, soak the part overnight in a bucket of diesel fuel.

Then the device can be assembled and enjoy the result. However, for full-fledged work, it is still recommended to purchase a new device. There are universal models that fit many vehicles.

Popular topic