Catalyst: What is it? Why do I need a catalyst on my car?

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

Catalytic converter

This part has a simple design, but the role it plays in the car is very big and serious. The operation of any internal combustion engine is accompanied by the emission of a variety of very different and very harmful substances (all these substances and toxic gases through the vehicle output line are released directly into the atmosphere). The neutralizer allows to significantly reduce the level of emission toxicity, thereby improving the ecological 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, turn into less toxic gases, which are then discharged through the exhaust pipe.

In the exhaust system, in addition to the neutralizer, oxygen sensors also work . They control the quality of the fuel mixture and affect the operation of the catalytic converter. You can find this device in the exhaust path between the silencer and the engine. The device is additionally protected by a metal screen, because during operation the device heats up. Look at how the catalyst looks like - its photo is placed below.

History of creation

In the 60s, the government of all developed countries of the world paid attention to the level of ecology and concerned about the number of emissions from the exhaust pipes of numerous cars. And it must be said that the law then did not regulate emission levels.

In 1970, the very first standards were adopted, which brought to the attention of the management of automobile concerns. In these standards, a list of indications of the content and quantity of particularly hazardous substances in exhaust toxic gases was provided.

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

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

The device and the principle of operation

Often set this device after the engine output pipe or it can be fixed directly to the exhaust manifold flange .

The device consists of a special carrier unit, a metal casing and heat-insulating materials.

The carrier consists of a plurality of cells similar to honeycombs. He performs almost all the work in the device. These honeycombs have a special coating - the working composition. It is interesting that the detail begins to work not immediately, but only after the temperature in the exhaust tract rises to 200-300 degrees.

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

The neutralizer cells are coated with a very thin film based on a unique platinum-iridium alloy. Those residues of toxic substances that are not burnt in the engine, when touching the hot surface of small cells instantly burn out. For this process, the catalyst takes up the remainder of oxygen, which remains in the already used toxic gases. As a result of this part of the exhaust pipe no longer toxic substances.


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

There are also disadvantages for a ceramic catalyst. This is its fragility. The part is absolutely unstable to various kinds of mechanical damage, and since the device is located under the bottom of the machine, there is a considerable probability of meeting the device with a curb, a stone, with anything. Then the part will break. Analogues from metal are much stronger, but their price is very high due to platinum alloy. For example, the VAZ catalyst in the event of a breakdown is not repaired, and many do not buy a new one because of the high cost.

Catalysts on different brands of cars

Cars depending on their manufacturer can vary significantly. The same applies to neutralizers. They are also different from model to model. We will consider the most popular brands of cars.


The catalyst on VAZ does not differ in anything. They are all metal, often fail due to various damages. Find the device in the car can be under the bottom, near the exhaust pipe of the engine. Often, in the event of a failure, catalyst repair is not possible.


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

In order to regulate the volume of oxygen, a lambda probe is used for a qualitative chemical reaction in the device, which is integrated into the computer.

Thus, the "Focus" catalyst consists of one catalytic collector and two sensors. With powerful engines, there are two collectors, as well as four sensors. The latter can be found both before and after the device. The neutralizer can be controlled from the instrument panel.

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

The performance check can be done very simply, and it is also easy to understand that replacement is necessary. With a non-working catalyst, the power characteristics drop substantially. To check the operation of the device, it is necessary to perform measurements of harmful substances in the exhaust of the machine. If the filters are clogged, then the level of harmful toxins will go off scale.

Also, it can be checked by removing the sensor installed before the neutralizer.

Then, using a special adapter, you must connect a pressure gauge and perform pressure measurements at different engine loads. Even if the device is out of order, repair of the catalyst is not possible.

If the catalyst "Ford" is clogged, in this case the old device is removed, and in its place a new one with increased norms is installed. It is also possible to replace the catalyst with a flame arrester or a universal neutralizer.

Toyota accelerator

"Toyota" in this issue also does not differ anything remarkable. These are the same honeycomb with a gold plating or platinum-iridium alloy. In new cars of this brand there are three such devices - they are connected to each other in series. Each of them is intended for cleaning gases from one particular type of harmful substances.

Proper operation of the catalyst

To ensure that the device as long as possible protects the ecological situation, it is necessary to use it correctly. So, the first and most important recommendation, which will prolong the equipment life, is quality fuel from famous and popular brands. Low-quality fuel can contain substances that can easily destroy the spraying of honeycombs. Particularly bad influence on the catalyst ("Kalina" is not an exception) is a metal such as tetrosvitsev. This substance has long been banned in many developed countries.

It must also be remembered that the neutralizer works under very high temperatures, so do not park the car where flammable objects, leaves, paper or anything else are lying around.

The driver, if desired, to save the catalyst should not often turn on the starter, if the machine does not start.

It is better to pause. Also, do not turn the crankshaft, turning off the spark plugs. Do not also start the engine with a tug.

How to understand that it broke

If, for example, a catalyst is installed on the car (Chevrolet Aveo, among others) and it is necessary to understand whether it works or not, there are several ways for this.

When the machine is working normally, then under any conditions the lamp on the dashboard, reporting the problem of the catalyst, does not light up.

If the part is in semi-working condition, then there is a lack of engine thrust at high revs. In the morning the car gets worse. Also, the car loses speed and increases fuel consumption. All this signals that the part needs to be replaced.

Repair by own hands

At numerous service stations, motorists are told that repairs of these devices are impossible. In fact, it is. However, if the part is clogged, you can try to rinse it. If there are several neutralizers in the machine, then the first is removed, and the second is washed. You can see such a catalyst - a photo of it below. Rinse recommended mixture for cleaning carburettors. If the result is too much sediment, it is necessary to soak the part for one night 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 suitable for many cars.

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