Q: How Does a Catalytic Converter Work?

asked by on

How does a catalytic converter work?

A catalytic converter is a device used to reduce the emissions of an automotive engine. Not enough oxygen is available to oxidize the carbon fuel in these engines completely into carbon dioxide and water; thus toxic by-products are produced. Catalytic converters are used in exhaust systems to provide a site for the chemical reaction of oxidation and the reduction of toxic by-products.

A catalytic converter uses basic chemical reactions to reduce the pollutants a car makes. It converts around 98% of the harmful fumes produced by a car engine into less harmful gases. It is composed of a metal housing with a ceramic honeycomb-like interior with insulating layers. This honeycomb interior has thin wall channels that are coated with a layer of aluminum oxide. This coating is porous and increases the surface area, allowing more reactions to take place and containing precious metals such as platinum, rhodium, and palladium. The construction requiring these precious metals is the cause of the consistent reports of recent catalytic converter thefts.

The fuel-injection system introduces the sensors needed to maintain the control of the exhaust environment within the converter required for a proper chemical reaction. This control system comprises oxygen sensors that monitor how much oxygen is in the exhaust stream, and in turn tells the engine computer to adjust the air-to-fuel ratio, keeping the catalytic converter running at the stoichiometric point (14:1 air-to-fuel) required and near 100% efficiency.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. How Does a Catalytic Converter Work?

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: Rattle/vibration on start up

Noises like this can be due to exhaust system faults such as loose pipes or hangers. If the noise is occurring at idle in park, if you securely set the parking brake, you may be able to walk around the...

Q: how many catalytic converters do it have

Your vehicle has two catalytic converters. These two converters are assembled, along with a muffler and some pipe, as one integral piece. The OEM Infiniti part number, if you require replacement of these converters, is 20020-CR91A. If you do a...

Q: White smoke coming from exhaust.

White smoke is an indication of coolant burning, especially if you having to add coolant frequently. If the white smoke is coming out the exhaust pipe then it is most likely being consumed in the combustion chamber. A common cause...

Related articles

Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...