A+-+Catalytic+Converters

· In mid 1970’s, automakers started making changes to car engines and fuel systems to keep up with the new laws that restrict the amount of pollution that cars can produce. · The function of the catalytic converter is to convert harmful pollutants into less harmful emissions before they leave the car’s exhaust system. · Modern cars engines monitor the amount of fuel they burn and try to match it with the stoichiometric point, which is the ideal ratio of fuel to air. · The stoichiometric point for gasoline is 14.7 : 1, meaning for every pound of gasoline, 14.7 pounds of air will be burned. This ratio could be changed slightly during driving. · Modern cars are equipped with three-way catalytic converters, which stands for the three emissions it reduces. · Once your catalytic converter reaches its operating temperature (known as "light off temperature") which is usually between 200 and 315 degrees Celsius the catalyst compound coating the inner ceramics start to convert the three regulated harmful emissions into less harmful emissions. The three EPA harmful emissions are: v __carbon monoxide (CO) __- deadly, odourless (combustion of gasoline) v __hydrocarbons or VOCs __- Volatile Organic Compounds- smog build up (unburned gasoline) v __Nitrogen Compounds __- smog and acid rain (heat in the engine forces nitrogen in the air to combine with oxygen) · A catalytic converter consists of three stages, a reduction catalyst and an oxidation catalyst, and a monitor system. 1) Reduction Catalyst -uses platinum and rhodium to help reduce NOx emissions. When an NO and NO 2 <span style="font-family: 'Times New Roman','serif'; font-size: 11.5pt;"> comes in contact with the catalyst, the catalyst rips the nitrogen atom out of the molecule, freeing the oxygen in the form of O <span style="font-family: 'Times New Roman','serif'; font-size: 8pt;">2 <span style="font-family: 'Times New Roman','serif'; font-size: 11.5pt;">. The remaining nitrogen atoms bond with other nitrogen atoms, forming N2.    ** 2NO => N2 + O2 **** or **** 2NO2 => N2 + 2O2 **  <span style="font-family: 'Times New Roman','serif'; font-size: 11.5pt; line-height: normal; margin: 0cm 0cm 0pt;">2) Oxidation Catalyst <span style="font-family: 'Times New Roman','serif'; font-size: 11.5pt; line-height: normal; margin: 0cm 0cm 0pt;">-reduces the unburned hydrocarbons and carbon monoxide by burning (oxidizing) them over a platinum and palladium catalyst, then combines it with the Oxygen gas inside the exhaust gas.
 * <span style="font-family: 'Times New Roman','serif'; font-size: 11.5pt; line-height: 115%;">How does a Catalytic Converter in a Car Work? **

2CO + O2 => 2CO2 3) After the reduction catalyst and oxidation catalyst, a control system monitors the exhaust stream. An oxygen sensor located close to the engine monitors how much oxygen is in the exhaust. The engine computer can then increase or decrease the oxygen level in the exhaust to match it with the stoichiometric point, and to make sure there is enough oxygen in the exhaust to allow the oxidization catalyst to burn the unburned hydrocarbons and CO. Improvements/Techniques <span style="background: white; font-family: Times New Roman; font-size: 11.5pt; margin: 0cm 0cm 1pt 36pt; text-indent: -18pt;">1) Move catalytic closer to engine <span style="background: white; font-family: Times New Roman; font-size: 11.5pt; margin: 0cm 0cm 1pt 36pt; text-indent: -18pt;">2) Preheat catalytic converter before turning your car on Interesting Facts <span style="background: white; font-family: Times New Roman; font-size: 11.5pt; margin: 0cm 0cm 1pt 36pt; text-indent: -18pt;">- Catalytic converters can vary in prices (based on the quality of the metals) but some can cost up to $1000, thieves can dismantle this piece within 60 seconds. <span style="background: white; font-family: Times New Roman; font-size: 11.5pt; margin: 0cm 0cm 1pt 36pt; text-indent: -18pt;">- The Emission Test checks catalytic converter to see if it is working properly. <span style="background: white; font-family: Times New Roman; font-size: 11.5pt; margin-left: 36pt; text-indent: -18pt;">- A normal catalytic converter is capable of destroying 98% of the harmful emissions.

<span style="background: white; font-family: Times New Roman; font-size: 11.5pt; margin-left: 36pt; text-indent: -18pt;">Citations

<span style="font-family: 'Times New Roman','serif'; font-size: 12pt; line-height: normal; margin: 0cm 0cm 10pt;"> · NSLS Everyday Science | Catalytic Converters. (n.d.). //National Synchrotron Light Source//. Retrieved November 24, 2010, from http://www.nsls.bnl.gov/about/everyday
 * <span style="line-height: normal; margin: 0cm 0cm 10pt; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Anglin, D. L. (2010). Catalytic Converter. //Grolier Multimedia Encyclopedia.// Retrieved November 25, 2010, from Grolier Online http://gme.grolier.com/article?assetid=0054700-0
 * <span style="line-height: normal; margin: 0cm 0cm 10pt; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Wright, M. (n.d.). How Does A Catalytic Converter Work - Understanding Catalytic Converter Repair. //DIY Auto Repair Help - Car Maintenance, Troubleshooting, How To Tutorials//. Retrieved November 24, 2010, from http://autorepair.about.com/od/glossary/ss/how-it_catalyti.htm
 * <span style="line-height: normal; margin: 0cm 0cm 10pt; mso-list: l0 level1 lfo1; mso-margin-bottom-alt: auto; mso-margin-top-alt: auto;"><span style="font-family: 'Times New Roman','serif'; font-size: 12pt;">Nice, K. (n.d.). HowStuffWorks "How Catalytic Converters Work". //HowStuffWorks - Learn How Everything Works!//. Retrieved November 24, 2010, from http://www.howstuffworks.com/catalytic-converter.htm