What makes a catalytic converter work, heat?
- Thread starter zach1900
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Chemistry.
http://auto.howstuffworks.com/catalytic-converter.htm
Catcons do work better when hot (and actually generate heat when working), but its the presence of a rare metal catalyst that enables chemical reactions to happen more easily. CO and partially-burned hydrocarbons will "burn" to CO2 and water, but not very readily in an exhaust system. Adding a catalyst to make that reaction "easier" is what makes it work.
Some of the other reactions (like the reduction stage where nitrogen oxides are broken down) won't readily happen at all without a catlyst.
http://auto.howstuffworks.com/catalytic-converter.htm
Catcons do work better when hot (and actually generate heat when working), but its the presence of a rare metal catalyst that enables chemical reactions to happen more easily. CO and partially-burned hydrocarbons will "burn" to CO2 and water, but not very readily in an exhaust system. Adding a catalyst to make that reaction "easier" is what makes it work.
Some of the other reactions (like the reduction stage where nitrogen oxides are broken down) won't readily happen at all without a catlyst.
There is a complex chemical process going on in a catalytic converter, but it does require that the catalytic converter to get hot to achieve the best efficiency.
In a perfect world, hydrocarbon would burn to water and CO2, but in the heat of a combustion chamber, there are another bunch of side reactions, that produce CO, NOx, and HC...these reactions are "fast" in forming the reaction products, and "slow" in breaking down, in terms of the combustion cycle...an infinitely slow exhaust stroke, and they'd break down eventually.
(These reactive species are what IMO drives oil antioxidant consumption when blowby hits the oil in the piston/bore).
The catalyst reduces the activation energy on these breakdown reactions so that they too can occur quickly.
The NOx, breaks back into N2 and O-, the CO picks up an O, and goes to CO2, and the HC gets back to H20 and CO2.
They are (IMO) a godsend, as the old pollution controls strangled engines, wasted fuel, and added ridiculous complexity.
(These reactive species are what IMO drives oil antioxidant consumption when blowby hits the oil in the piston/bore).
The catalyst reduces the activation energy on these breakdown reactions so that they too can occur quickly.
The NOx, breaks back into N2 and O-, the CO picks up an O, and goes to CO2, and the HC gets back to H20 and CO2.
They are (IMO) a godsend, as the old pollution controls strangled engines, wasted fuel, and added ridiculous complexity.
Back in the day I had friends and we would talk about breaking the porcelain in it to free it up.
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