The exhaust system is one of the key elements of a car’s construction. Its primary function is to remove the exhaust gases produced during fuel combustion. While it may seem that this system is simple and mainly consists of a muffler and exhaust pipe, it actually also includes an extremely important component – the car catalytic converter.
What is a car catalytic converter?
Although the exhaust system has a relatively simple construction, its operation is more complex. One of the key elements is the catalytic converter, also called a reactor or catalytic converter. Its main function is to reduce the amount of harmful substances in the exhaust gases. It acts as a filter that traps harmful chemical compounds and neutralizes them before they leave the exhaust system.
Modern vehicles also use fuel vapor absorbers and DPF filters in diesel-powered cars, which serve a similar function as the catalytic converter in gasoline engines. The current Euro 6D emissions standard requires every vehicle to be equipped with an effective exhaust reduction system. Otherwise, the vehicle will not pass homologation and will not be allowed for sale.
If, during a periodic technical inspection, the diagnostician detects the absence of a catalytic converter, the vehicle will not receive a positive assessment and will not be allowed on the road.
Structure of a catalytic converter
The catalytic converter is located at the beginning of the exhaust system and resembles a muffler. It consists of three main elements:
Housing – a metal canister connected to the collector in the exhaust system, through which the exhaust gases flow.
Carrier – a honeycomb structure element consisting of numerous channels that filter the exhaust gases. It can be made of ceramic or metal.
Coating – a layer covering the carrier, made of precious metals such as platinum, palladium, or rhodium. These elements react chemically with the exhaust gases, neutralizing harmful substances.
It’s worth adding that the presence of precious metals makes catalytic converters a target for theft. Their value on the secondary market is so high that this practice has become widespread.
How does a catalytic converter work?
The catalytic converter purifies the exhaust gases by reducing the amount of toxic substances, such as carbon monoxide, hydrocarbons, and nitrogen oxides. This process occurs at high temperatures (400–800°C), when catalytic reactions take place. Therefore, the catalytic converter reaches its full efficiency only after warming up.
Modern vehicles are often equipped with multiple catalytic converters, which allow for even more effective emission reduction. There are also special fuel additives that can support the catalytic converter’s operation, but they do not replace the exhaust filtration process itself.
Symptoms of a faulty catalytic converter
The catalytic converter is a wear item and may degrade or break over time. Its failure manifests in the following symptoms:
- A characteristic rattling noise coming from the exhaust system.
- The check engine light turning on.
- A drop in engine power.
- Increased fuel consumption.
- Uneven engine operation.
- Excessive smoke from the exhaust pipe.
Not all symptoms need to occur simultaneously, and the check engine light may also indicate other issues, such as a lambda sensor or DPF filter failure.
Causes of catalytic converter failure
The most common causes of catalytic converter failure include:
- Frequent short-distance driving, which prevents the catalytic converter from reaching the proper temperature.
- Damage to the ignition system components.
- Engine wear and the entry of unburned fuel into the exhaust system.
- Improper adjustment of the LPG system.
- Mechanical damage, such as the exhaust system hitting an obstacle.
