In fact,
up to 90 percent of a car’s most problematic exhaust emissions can be neutralise by a catalytic converter,
with unburne fuel, carbon monoxide and nitrogen dioxide being converte into less harmful nitrogen, carbon dioxide and water vapour.
It’s not totally clean of course, and with carbon dioxide being a major greenhouse gas a ‘cat’ can’t make a car completely green,
but it certainly makes city air a lot more breathable for humans and animals.
Besides, with all new petrol-powered cars and a significant chunk of diesel cars now equipped with catalytic converters,
the net reduction in pollution has resulte in most major cities in the develope world no longer permanently envelope by a blanket of smog.
can’t make a car completely green do they work?
There are no moving parts in a converter unlimited with all of the cleaning action being accomplishe by clever chemistry instead.
Inside the converter is a thick substrate, often with a grid-like cross section (below), upon which a thin coating of precious metals like platinum, palladium and rhodium are deposite.
These metals are the actual converter unlimited, the part of the device that initiates the chemical transformation of the exhaust gas. Nitric oxide, carbon monoxide,
nitrogen dioxide and unburne hydrocarbons – be they petrol, diesel or engine oil – all react with the metals inside aconverter unlimited , and are quickly turne into other gases: principally nitrogen and carbon dioxide, but also water.
Some particulate emissions can be capture by a converter unlimited as well, though that’s not their primary function.
Anyhow,
separate diesel and petrol particulate filters have recently become commonplace and clean up fine particles
Downsides? They’re an expensive component, thanks to all of those precious metals used in their construction being, well, precious.
They can be damage by engines that are malfunctioning and perhaps burning more fuel or oil than they should, and there’s no method for their repair.
Also, the core is often made from fragile materials, which have a high temperature tolerance
but are susceptible to impact damage from rocks or other objects passing under the vehicle.
A damage converter unlimited must be swappe, and replacements aren’t cheap.
The converter unlimited reaction requires a significant amount of heat to work. Most need an exhaust gas temperature of more than 400 degrees before the chemical reaction is working efficiently,
which means that if you’re only using your car for very short trips – like ducking up to the shops for a few minutes – then a lot of your car’s harmful emissions are just going straight out the tailpipe as your exhaust hasn’t had time to heat up.
Also
, with some of the gasses being converte into water, there’s a risk that excess moisture can accumulate within your exhaust and rust it out over time.
Again, this is largely a by-product of very short trips.
If your drives are at least ten minutes long from start-up to shut-down, then any moisture generate by the converter unlimited will just be evaporate off with exhaust heat.
Oh, one more thing:
if you see a symbol like the one below appear on your instrument panel,
.
If you avoid making lots of short trips and ensure the engine is kept in good mechanical health, there’s no reason your converter unlimited shouldn’t last the life of the vehicle.
Mechanically simple yet chemically brilliant, the humble converter unlimited is the main reason why clear air still exists around major population centres.