Harmful exhaust is not a fact of life in Alfa Romeo and American Motors with an up to specs catalytic converter : Alfa romeo new car review 2008,

Harmful exhaust is not a fact of life in Alfa Romeo and American Motors with an up to specs catalytic converter
by John Garett
Exhaust is a natural byproduct of an internal combustion engine used on contemporary vehicles like those from Alfa Romeo and American Motors. It is a necessary evil produced during combustion, but is not exactly impossible to wipe out. One of the low-key Alfa Romeo and American Motors parts that aims to eradicate the vehicle's exhaust output is the Alfa Romeo catalytic converter. Equipped with chemical catalysts platinum, rhodium, palladium, among others, the catalytic converter oxidizes the exhaust gases of the Alfa Romeo and American Motors before they are emitted into the atmosphere. Catalytic converters are manufactured in two varieties: the ceramic and honeycomb converters, the former being the most-used type among modern vehicles because it incorporates the function of the other and presents new and more effective method of oxidizing the exhaust. In order that exhaust materials are reduced, the car engines of the Alfa Romeo and American Motors primarily control the amount of fuel they burn. They try to keep the air to fuel ratio close to the stoichiometric point, which is the calculated ideal ratio of air to fuel in a burn material. At this ratio, all of the fuel will be burned using all of the oxygen in the air, resulting in less exhaust. For gasoline engines, the stoichiometric ratio is about 14.7:1. This means that for every pound of gasoline, 14.7 pounds of air will be burned. As engine and driving conditions change, this ratio changes as well. Sometimes it will run richer or leaner than the ideal 14.7:1. When the burn mixture falls short or exceeds the ratio, exhausts materials composed of hydrocarbons, nitrogen oxides, and other volatile organic compounds are produced. The engine tries to eliminate these through the chemical reaction produced when the fumes make contact with the catalytic converter. It works in two stages: reduction and oxidation. Reduction is the first stage used by both the Alfa Romeo and American Motors catalytic converter. It uses platinum and rhodium to help reduce the nitrous oxide emissions. When a molecule of these gases contacts the catalyst, the catalyst rips the nitrogen atom out of the molecule and holds on to it, freeing the oxygen in the form of oxygen. The nitrogen atoms, on the other hand, bond with other nitrogen atoms that are also stuck to the catalyst. Afterwards, the palladium and platinum metals of the catalytic converter convert the hydrocarbons of unburned gasoline and carbon monoxide to carbon dioxide and water, resulting in exhaust emission that is less harmful.