Catalytic Converter Case Study

9732 Words 39 Pages
CHAPTER 1
INTRODUCTION

1.1 BACKGROUND
The catalytic converter was invented by Eugene Houdry, a French mechanical engineer and skilled in catalytic oil refining who lived in the United States around 1950. The invention of catalytic converter has a major role in controlling harmful emissions. When the paper of smog in Los Angeles was published, Houdry became anxious about the role of smoke stack and automobile exhaust in air pollution and established a company, Oxy-Catalyst. Houdry primary developed catalytic converters for smoke stacks, he then manufactured catalytic converters for warehouse fork lifts which uses low grade non leaded gasoline. Then he began his research to progress catalytic converters for gasoline engines that became used
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After the catalytic action, carbon dioxide, oxygen, vapor and NOX will remains as the byproduct leading to the exhaust end. This type of catalytic converter is widely used in diesel engines to reduce hydrocarbon (HC) and carbon monoxide (CO) emissions. These are also used on gasoline engines in American and Canadian market automobiles until 1981. Because of their failure to control oxides of nitrogen, they were outdated by invention of three-way catalytic converters.
3.1.2 Three - way catalytic converter
Since 1981, three-way catalytic converters are used in vehicle emission control systems in the U.S and Canada. The reduction and oxidation catalysts are normally contained in a common housing, however in some occasions they may be housed individually in case of three-way converters. A three-way catalytic converter will perform the three simultaneous tasks:
 Reduction of nitrogen oxides to nitrogen and oxygen: 2NOX → xO2 + N2
 Oxidation of carbon monoxide to carbon
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The main drawback of platinum is its low activity for the conversion of NOX and its high price relative to palladium. In addition, platinum is sensitive to the high temperatures which may occur in the catalytic converter during high engine loads. Palladium, which is presently the inexpensive among the three metals, has admirable activity for the oxidation of hydrocarbons as well as very good thermal durability. In addition, with the use of a well-designed wash coat, palladium can have very good activity for the removal of NOX. The drawbacks of palladium include its sensitivity to poisons. Rhodium, which is now the most expensive among the three, has the highest activity for the removal of NOX from the exhaust. Rhodium has weighty activity for the oxidation of HC and CO and very virtuous resistance to the poisons present in the exhaust stream. The main limitation of rhodium is its high

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