Catalytic converter, or catalyst – what is it used for and why is it sometimes stolen?

The increasingly stringent exhaust emission standards applied to cars mean that modern cars are full of solutions designed to reduce emissions of harmful substances. One of them is a catalytic converter, i.e. a catalyst purifying the exhaust gas.

What is a catalytic converter, commonly called a “catalyst”?

The catalyst (converter or catalytic converter) is part of the exhaust system. Inside, there is a metal or ceramic honeycomb insert that allows the exhaust fumes to flow and at the same time purifies them. The catalyst reduces the carbon monoxide content in the exhaust gas, as well as reduces nitrogen oxides in diesel engines.

 

 

Catalysts make modern vehicles characterized by low emissions of harmful substances, including nitrogen oxides, carbon oxides and hydrocarbons. It is worth remembering that substances show varying degrees of harm to the environment. Carbon dioxide is not directly harmful to humans. A much bigger problem pose nitrogen oxides, which as a pollutant do not occur in the exhaust gases emitted in gasoline engines, but only in diesel units.

Catalysts installed in diesel engines are different from those used in gasoline engines. Catalytic converters vary depending on which Euro standard they meet. They come with a metal insert or a ceramic block. They usually last at least 150.000-200.000 km.

 

How does the catalytic converter work?

In a heated catalyst, nitrogen oxides and other harmful substances are reduced. The catalyst controls the content of nitrogen oxides and other substances, such as carbon monoxide. Nitrogen occurs only in the case of diesel engines and the catalyst is responsible for reducing its emissions. In order to reduce nitrogen oxides in diesel engines, manufacturers install additional converters using urea solution (the Adblue liquid) as a reaction catalyst.

The device operates at a high temperature – at least 300 degrees Celsius. It is heated by exhaust fumes. In order for the catalyst heating process to be fast, these devices use insulated covers, additional heaters, as well as air blowing to the exhaust manifold.

 

 

The smooth operation of the catalyst is possible thanks to the lambda probes. Both behind and in front of the catalytic converter there are special probes that control the air content in the exhaust fumes. Their readings are used to control the operation of the engine and select the right combustion mixture. Correct operation of the engine translates into effective operation of the catalyst, where reduction and oxidation processes occur as a result of the reaction.

 

Where is the catalytic converter located?

The catalytic converter is located in the chassis and is part of the exhaust system. Due to its location, it is susceptible to mechanical damage and theft due to the content of rare elements – platinum, palladium and rhodium. 

 

 

What is the catalyst made of and is it resistant to damage?

Catalysts used in cars are divided according to the inserts used in them into the following groups:

• metallic
• ceramic

The converter with a catalytic metal block is characterized by greater resistance than an analogous device with a ceramic block. The metal insert is more durable and unlikely to be damaged by, for example, impacts or shocks. However, mechanical damage is not everything. 

 

 

Is the theft of catalysts still a big problem?

Catalytic converters are one of the parts of the car that are quite easy to remove and then sell. Due to the rising prices of rare metals, catalysts are now often stolen.

 

How much is a catalytic converter worth?

Used catalysts used in cars cost even more than a thousand euros. The main factor influencing the cost of the catalyst are the rising prices of the precious metals included in the catalyst, such as platinum.

 

 

Is the catalytic converter a replacement part?

Yes, the catalyst can be replaced with a new one, but most often only the cartridge is replaced due to the cost. An even cheaper way is to clean the catalyst so that it can work efficiently again and reduce exhaust emissions, including, for example, hydrocarbons.

There are several methods for cleaning catalysts:

• washing in ultrasonic cleaners
• burning off the insert
• cleaning with chemicals and water under high pressure

 

What are the most common problems with the catalytic converter?

The most common problems with the catalytic converter are:

• Pollution: Catalysts can be contaminated by various substances, such as poor quality fuel, engine oil, heavy metals or pollutant deposits in exhaust gases. These impurities may limit the performance of the catalyst and lead to its damage.
• Mechanical damage: Catalysts are placed under the car and exposed to various mechanical damage, such as damage done by stones, damage when driving on uneven roads or bumps. Such damage may cause catalyst cracks or fractures.
• Effect of high temperatures: Catalysts must operate at the right temperature to efficiently convert harmful substances in the exhaust fumes. If the engine is improperly designed or operates in conditions where the exhaust gas temperature is too high, this may lead to overheating of the catalytic converter and its damage.
• Effects of toxic substances: Incorrect fuel or fuel additives containing toxic substances such as lead or some engine oil additives may damage the catalyst. These substances may deposit on the surface of the catalyst and reduce its performance.
• Accident damage: Serious car accidents can damage the catalytic converter, especially if the car hits an obstacle with great force. In such cases, it may be necessary to replace the catalyst.

The most common symptoms of catalyst failure include:

• engine start problems
• waving turnover after starting the engine
• lake of power
• driving noise coming from the exhaust system
• increase in combustion

 

Since when have cars been equipped with the catalytic converter?

Catalytic converters have been installed in cars since the early 1980s while they have been used serially since the 1990s. Some decide to uninstall the catalytic converter and insert a cap, which is illegal and such a car should not be bought.

 

Why are catalytic converters installed in cars?

All internal combustion engines produce harmful substances during operation. High engine operating temperatures mean that poisonous substances – nitrogen oxides and hydrocarbons – appear in the exhaust gas. Thanks to the work of the catalytic converter – if it is properly heated – there is a reduction of nitrogen oxides in the flue gas. Due to the strict exhaust emission standards applied to cars, the content of nitrogen oxides in the exhaust must be at a sufficiently low level. In the engine, as a result of the reaction, hydrocarbons and carbon monoxide are excreted externally in the flue gas. A heated catalyst is able to significantly reduce the emission of this type of substance.