Catalytic converter

Legislators have been working hand in hand with vehicle manufacturers for some time to reduce noxious gas emissions from cars. The advent of more fuel-efficient cars has gone some of the way in dealing with this problem, but the compulsory fitment of catalytic converters on vehicles has made the most significant contribution to reducing harmful emissions.

What is a catalytic converter?

• The catalytic converter is a steel box mounted on the exhaust system between the exhaust manifold and the muffler.
• Inside the box is a ceramic honeycomb, which is coated with chemicals such as aluminium oxide, platinum, palladium and rhodium.
• These chemicals act as a catalyst.
• Some vehicles use ceramic beads coated with the same substances.
• It is usually fitted as close to the manifold as possible because the catalytic converter only functions at high temperatures.

How does it work?

• The catalytic converter was designed to deal with harmful pollution causing gases that are produced in the combustion chamber a vehicle's engine.
• The catalytic converter turns gases such as carbon monoxide, hydrocarbons and nitrogen oxides into non-toxic emissions such as carbon dioxide and water vapour.
• The toxic gases pass over the catalytic converter's chemical coated ceramic honeycomb and the resultant chemical reaction renders the gases harmless.
• The catalytic converter only works at high temperatures, by mounting it near the manifold the converter heats up quickly.
• When the engine is cold, noxious gases are getting through to the atmosphere.
• It is important to have your car in top mechanical condition with the cooling and fuel systems working efficiently to minimise harmful emissions.
• If you drive your car on short journeys all the time and your car doesn't get to its correct working temperature then you are probably contributing to the pollution problem.
• You cannot use leaded fuel with a catalytic converter as the lead coats the chemicals on the honeycomb and the gases can no longer come into contact with them, which renders it ineffective.
• While the catalytic converter requires no maintenance and would be expected to last the life of the vehicle with normal use, it can be damaged by impact.