Catylytic converters

Sometimes the mixture can be lean an air-to-fuel ratio higher than These emissions are mostly benign, although carbon dioxide emissions are believed to contribute to global warming.

Because the combustion process is never perfect, some smaller amounts of more harmful emissions are also produced in car engines. Catalytic converters are designed to reduce all three:. Gallon for gallon, new lawn mower engines contribute 93 times more smog-forming emissions than new cars. It's no wonder that the EPA and the state regulators of California are trying hard to get golf ball-sized catalytic converters into lawn mower and other small engines.

However, just like in the s, the lawmakers are being met with a powerful lobby. Four smaller lawn mower engine manufacturers have refuted this charge. California democrats and the EPA think it has more to do with the bottom line. Pending regulations proposed in California could reduce emissions by the equivalent of , cars per day [source: Barringer ].

In chemistry, a catalyst is a substance that causes or accelerates a chemical reaction without itself being affected. Catalysts participate in the reactions, but are neither reactants nor products of the reaction they catalyze.

In the human body, enzymes are naturally occurring catalysts responsible for many essential biochemical reactions [source: Chemicool ]. In the catalytic converter, there are two different types of catalyst at work, a reduction catalyst and an oxidation catalyst. The idea is to create a structure that exposes the maximum surface area of catalyst to the exhaust stream, while also minimizing the amount of catalyst required, as the materials are extremely expensive.

Some of the newest converters have even started to use gold mixed with the more traditional catalysts. Most modern cars are equipped with three-way catalytic converters. This refers to the three regulated emissions it helps to reduce. It uses platinum and rhodium to help reduce the NOx emissions.

When an NO or NO2 molecule 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 O2. The nitrogen atoms bond with other nitrogen atoms that are also stuck to the catalyst, forming N2.

For example:. The oxidation catalyst is the second stage of the catalytic converter. It reduces the unburned hydrocarbons and carbon monoxide by burning oxidizing them over a platinum and palladium catalyst. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas.

There are two main types of structures used in catalytic converters -- honeycomb and ceramic beads. Most cars today use a honeycomb structure. In the next section, we'll look at the third stage of the conversion process and how you can get the most from your catalytic converter. The third stage of conversion is a control system that monitors the exhaust stream, and uses this information to control the fuel injection system. There is an oxygen sensor mounted upstream of the catalytic converter, meaning it is closer to the engine than the converter.

This sensor tells the engine computer how much oxygen is in the exhaust. The engine computer can increase or decrease the amount of oxygen in the exhaust by adjusting the air-to-fuel ratio. This control scheme allows the engine computer to make sure that the engine is running at close to the stoichiometric point, and also to make sure that there is enough oxygen in the exhaust to allow the oxidization catalyst to burn the unburned hydrocarbons and CO.

The catalytic converter does a great job at reducing the pollution, but it can still be improved substantially. Currently, the scrap catalytic converters for this vehicle are the fourth most expensive. Ford is reputed for equipping its vehicle with high-quality catalytic converters. The GM vehicles come in a variety of sizes.

The range of vehicles usually comes equipped with two sizes of catalytic converters. This range of vehicles equips the small foreign category catalytic converters and the sizeable foreign Honda converters. However, you can opt. This amount excludes labor charges. The Toyota Prius series is reputed for being a victim of thefts of scrap catalytic converters.

Since it is a hybrid vehicle, the equipment corrodes less and is very accessible to thieves. Save my name, email, and website in this browser for the next time I comment. Courtesy of Costa Mesa Police Department. Cars lined up at ExperTec Automotive in Huntington Beach on Saturday, November 13, where police were sponsoring a catalytic converter etching event to prevent thefts. The free public service, sponsored by local police departments, aimed to deter thefts.

Converters are increasingly being stolen for the precious metals they contain. Catalytic converters, like this one, are being stolen for the precious metals they contain. Police were able to return one etched catalytic converter to its owner after it was found, Costa Mesa Police Chief Ron Lawrence said. Catalytic converters are coveted by thieves because they contain honeycomb structures coated with precious metals such as platinum, palladium and rhodium, which could net criminals hundreds of dollars at a metal recycler for each one.

Among the targeted types, Capt.