What is a Catalytic Converter : Types & Its Working

In worldwide, there are billions of different cars on the roads which cause air pollution. So this is the major issue in every city. To overcome this issue, here is a device namely catalytic converter after so many modifications to fuel systems and car engines. This device is used to reduce harmful pollutants to less harmful emissions before leaving the exhaust system of the car.

The main emissions produced by car engines are N2, CO2 & H20, so this converter will reduce all these emissions. This article discusses an overview of a catalytic converter and its working.

What is a Catalytic Converter?

A catalytic converter (Cat-Con) is an essential part of the exhaust system of automobiles. It takes very dangerous pollutants like carbon monoxide and converts them chemically to less dangerous pollutants like carbon dioxide. The harmful compounds mainly include nitrogen gas, carbon monoxide, hydrocarbons, nitrogen oxides, etc. The catalytic converter device in automobiles will reduce overall harmful emissions.

Catalytic Converter
Catalytic Converter

The catalytic converter history is; the first catalytic converter was developed by engineers like Carl D. Keith & John J. Mooney @ the Engelhard Corporation in 1973. In the 1970s, Dr. William C. Pfefferle was introduced a catalytic combustor to use in gas turbines by letting combustion without major formation of CO & NiO2.

In the year 1975, the first converter was introduced because of the demand in-laws on exhaust from the government. So this device was considered essential to meet up regulations without decreasing the performance of the vehicle.


The construction of the catalytic converter includes a honeycomb core that is covered with different metals like rhodium & platinum. The main reason to use these metals is, it responds very quickly with the exhaust gases of the engine.


They decrease the toxic contents within the gases & switch them into CO2 & H2O. In the beginning, it responds to the carbon monoxide which is produced by gasoline combustion, and also through the hydrocarbons produced by unburned fuel & other NIO2 emissions. So, this converter will convert these harmful emissions into less harmful ones.

Construction of Catalytic Converter
Construction of Catalytic Converter

Catalytic converter needs 400 °C of temperature or 752 °F to function efficiently. Thus, they are arranged near to the car engine otherwise one or more tiny catalytic converters like pre-cats are located instantly behind the exhaust manifold.

In a catalytic converter, the catalyst is made generally from platinum otherwise a related metal like palladium/ rhodium. Gases will supply throughout a ceramic honeycomb and that is arranged in the cat housing. Here, honeycomb is lined through metals to reduce emissions. The catalysts available in automobiles are mainly two types like reduction catalysts and oxidation catalysts.

The main function of the reduction catalyst is to assist in reducing the pollution of nitrogen oxide by eliminating oxygen. These are divided into two separate gases like nitrogen & oxygen. Oxidation catalysts are mainly used for changing the gases from carbon monoxide (CO) to carbon dioxide (CO2) with a reverse method of including oxygen.

An oxygen sensor is placed near the converter to inform an ECU (electronic control unit) regarding how much O2 is discovered within the exhaust gases. So this assists an automobile vehicle to run more efficiently by allowing the engine of the car to supply the converter through sufficient oxygen to finish the process of oxidation.

Types of Catalytic Converter

Catalytic converters are available in different types like oxidation catalyst, dual bed catalyst, and three-way.

Oxidation Catalyst

The first type of catalytic converter is an oxidation catalyst. This type of catalyst decreases harmful pollutants like CO (carbon monoxide) & HC (fuel hydrocarbon) within the exhaust. At the same time, it frequently utilizes an inferior air injection. But, this type of catalyst simply decreases a part of the pollutants.

Dual-bed Catalyst

This is the second type of catalyst which provides more perfection. This type of catalyst mainly works within two stages where the first stage assists in decreasing the emission quantity from NiO2. The second phase responds through the hydrocarbons which are formed through unburned carbon mono oxide & fuel. In two stages, the manufacturers will provide the secondary air injection.

Three-Way Catalytic Converter

This is the last type of converter which aids in changing the dangerous gases into harmless generated from the car engine.

The car engine will exhaust different gases which include hazardous substances that cause harm to the atmosphere like NiO2, CO, CO2, etc. These converts mainly change them into less harmful CO2, nitrogen & water.

This device simply decreases all the 3 pollutants and it performs more economically. So, most of the designers use this type of converter within their cars which requires them to meet harsh emission values.

What does a Catalytic Converter Do?

These are mainly accountable for reducing harmful compounds to less like O2, CO2, Ni, & H2O water. This can be done through a chemical procedure that quickly reduces the compounds before they go away from the car.

These converters include catalysts that convert the harmful compounds. Generally, the normal method takes too much time. Catalysts within the converter will make the procedure very quicker & reduces different compounds in very little time. In modern cars, 3 stage converters are majorly used.

In catalytic converters, both the stages like the first and second mainly involve both reduction & oxidation catalysts. Generally, the reduction catalyst comes from platinum & radium whereas the oxidation comes from platinum & palladium. As you can observe, platinum is mainly used in different areas through catalytic converters which reduce harmful compounds.

The last phase comprises the engine with an oxygen sensor & it detects how much oxygen is within the exhaust system. Here, fuel injection mainly depends on this procedure when the engines increase/decrease then how much fuel is infused into the gas chambers.

For instance, if the oxygen is presently less and the converter needs more time, then low fuel will be infused until the levels of oxygen are superior. This balances the complete pollutants which are generated from the exhaust system. There is also a two-phase catalytic converter that performs differently. The primary phase is particularly decreased NiO2 whereas the secondary phase decreases CO & hydrocarbons.

Bad Catalytic Converter Symptoms

The signs of a clogged catalytic converter mainly include the following.

  • Waning fuel efficiency
  • Verify warning light
  • Car Smells like rotten eggs
  • Engine issues
  • Less acceleration
  • The emission test will be failed
  • Engine Light will be ON
  • A Rattling Noise within the Engine
  • Getting fewer miles for each gallon
  • Car Jerks ahead
  • Fuel loss throughout acceleration
  • The engine will be misfired

Changing a bad catalytic converter is the main repair in cars which is related to a check engine warning light. Generally, this converter replacement mainly takes hours and is also expensive based on the cars. When catalytic converter damages then it causes on poor performance, fuel bill will be high & potential inside damage.

How to Clean a Catalytic Converter?

The catalytic converter can be cleaned in two ways like without cleaning it and cleaning it but the following things must be considered before cleaning this converter.

  • The converter is packed full or not
  • Need to check the slack parts
  • Purify catalyst
  • Consumption of oil

The required equipment to clean the catalytic converter are; hand gloves, goggles for eyes safety, tub, degreaser, oil, Jack stand, wrenches, pressure washer, oxygen sensor wrench, shop towels, etc.

Clean Catalytic Converter without Removing It

  • This converter mainly functions as a cleaner to obtain all cleaned up. If you believe that it is an extended task for cleaning your converter without detaching it.
  • At first, safety checks are very significant if you want to clean the converter without detaching it from the car & if you believe the whole thing is okay then you can attempt the following techniques.
  • Make sure that the cleaner is best or not
  • Stay until the converter tank includes the correct quantity of fuel
  • The cleaner should add to the converter tank
  • Ride your car
  • Refill converter tank when almost empty

Clean Catalytic Converter by Removing It

These are used as a cleaner to get it all cleaned up. Provided the cleaner for this converter does not function correctly, then the other cleaning technique will command by removing & soaking it.

  • Let the car get cool & jack It
  • Place the converter
  • Eliminate oxygen sensor
  • Detach converter
  • Clean the converter
  • Soak it
  • Wash it & dry
  • Again reinstall it & go for a test drive

Catalytic Converter Theft

This converter is an extremely special type of filter used in the exhaust system of cars that decreases dangerous emissions. This kind of converter is bolted under the car & it’s susceptible to thieves as it includes different expensive metals. So day by day, the converter robberies have been increasing & the devices are costly to put back. The following steps might assist you in protecting your vehicle from stealing a catalytic converter.

  • Robbers mainly focusing on catalytic converters as they include valuable metals
  • These devices are in danger as they are easy to steal.
  • These are costly to put back.
  • The following methods are used to defend against this converter theft
  • Need to fetch the car’s license plate number onto the converter.
  • The car must be parked in lighting areas.
  • Fix an anti-theft appliance.

Catalytic Converter Lock

These are mainly used in cars to stop dangerous emissions from exhaust systems through rotating pollutants into safe gasses. The theft rates of these devices are very high as they include expensive metals such as palladium, platinum, rhodium, etc.

So to take appropriate action on the converter theft, there are different catalytic converter locks are available from different manufacturers. This is one kind of security device used to give protection for the converter. The designing of this security device can be done by using stainless steel with marine grade to stop the robbery of catalytic components in vehicles.

Generally, catalytic converter lock is used in expensive vehicles like vans, pick-up trucks, the Toyota Prius. & Honda Jazz.

How to Choose a Catalytic Converter?

The catalytic converter device controls the emission which is connected to the exhaust system of a car. In many countries, a yearly inspection for emission is necessary to renovate the registration of your vehicle. If your car is failed annual inspection for emission, so there is a chance to replace the unit of the catalytic converter.

Selecting the correct catalytic converter can be hard for your vehicle. So to make it simple, the following points need to follow for the replacement of a catalytic converter for your car.

  • Check the model, making year and model
  • Recognize the level of emission for your vehicle
  • Recognize the exact converter grade
  • Choose the configuration for the installation
  • Check the oxygen sensor

Advantages & Disadvantages

The advantages of catalytic converter mainly include the following. If we remove the catalytic converter then there are some benefits like the following.

  • Catalytic converters reduce 87% of hydrocarbon emissions, 85% carbon monoxide & 62% nitrous oxide throughout the expected car life.
  • The catalytic converter is an essential device in gas-fueled cars. If the car generates emissions, it requires this converter.
  • It reduces harmful emissions from the cars
  • Once a catalytic converter is removed, then the horsepower in some cars will be increased. As a result, we can produce more horsepower without it.
  • This converter should work very hard to get similar energy. If we remove this, it will reduce the burden & you can attain better gas mileage.
  • Exhaust sounds can be removed once it is removed.
  • Engine performance can be enhanced

The disadvantages of catalytic converter mainly include the following.

  • In some countries like the USA, removing a catalytic converter is illegal without reason otherwise you have to follow some procedure to remove this. Otherwise, you will get some fines.
  • The fault code may be activated within your vehicle by detaching a catalytic converter.
  • Harmful gases can be leaked within the atmosphere, so they can affect your health.
  • The catalytic converter reduces fuel consumption. If we remove this, you have to pay for the fuel.
  • Detaching this converter may cause low-end torque loss while operating the car.
  • Noise can be generated while driving
  • Without a catalytic converter, you can utilize more gasoline
  • Visual inspection can be failed for cars

Thus, this is all about an overview of a catalytic converter which is used in exhaust systems of automobiles, electrical generators, mining equipment, forklifts, buses, trucks, locomotives, on ships & motorcycles. These are also utilized on some wood-based stoves to manage emissions. Here is a question for you, what is a high flow catalytic converter?