catalytic converter


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catalytic converter:

see internal-combustion engineinternal-combustion engine,
one in which combustion of the fuel takes place in a confined space, producing expanding gases that are used directly to provide mechanical power.
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catalytic converter

[¦kad·əl¦id·ik kən′vərd·ər]
(chemical engineering)
A device that is fitted to the exhaust system of an automotive vehicle and contains a catalyst capable of converting potentially polluting exhaust gases into harmless or less harmful products.

Catalytic converter

An aftertreatment device used for pollutant removal from automotive exhaust. Since the 1975 model year, increasingly stringent government regulations for the allowable emission levels of carbon monoxide (CO), hydrocarbons (HC), and oxides of nitrogen (NOx) have resulted in the use of catalytic converters on most passenger vehicles sold in the United States. The task of the catalytic converter is to promote chemical reactions for the conversion of these pollutants to carbon dioxide, water, and nitrogen.

For automotive exhaust applications, the pollutant removal reactions are the oxidation of carbon monoxide and hydrocarbons and the reduction of nitrogen oxides. Metals are the catalytic agents most often employed for this task. Small quantities of these metals, when present in a highly dispersed form (often as individual atoms), provide sites upon which the reactant molecules may interact and the reaction proceed.

Two types of catalyst systems, oxidation and three-way, are found in automotive applications. Oxidation catalysts remove only CO and HC, leaving NOx unchanged. Platinum and palladium are generally used as the active metals in oxidation catalysts. Three-way catalysts are capable of removing all three pollutants simultaneously, provided that the catalyst is maintained in a “chemically correct” environment that is neither overly oxidizing nor reducing. In both oxidation and three-way catalyst systems, the production of undesirable reaction products, such as sulfates and ammonia, must be avoided.

Maintaining effective catalytic function over long periods of vehicle operation is often a major problem. Catalytic activity will deteriorate due to two causes, poisoning of the active sites by contaminants, such as lead and phosphorus, and exposure to excessively high temperatures. To achieve efficient emission control, it is thus paramount that catalyst-equipped vehicles be operated only with lead-free fuel and that proper engine maintenance procedures be followed. See Automotive engine

catalytic converter

a device using three-way catalysts to reduce the obnoxious and poisonous components of the products of combustion (mainly oxides of nitrogen, carbon monoxide, and unburnt hydrocarbons) from the exhausts of motor vehicles
References in periodicals archive ?
But those metals are difficult to extract from the device, and local scrap dealers say they typically won't pay more than about $30 for a used catalytic converter.
Inside the suspect's car, deputies found four stolen catalytic converters, including the one that had just been reported stolen, Cambra said.
Honda's new catalytic converter efficiently reduces NOx in a lean-burn atmosphere, enabling diesel engines to rival gasoline engines in cleanliness.
auto industry has been transitioning to a greater proportion of palladium in the manufacture of new catalytic converters," says Ashok Kumar, director of A-1 Specialized Services & Supplies, Inc.
Environmental Protection Agency standards, catalytic converters would reduce emissions more, Westerholm says.
This program will require 380,000 manifolds and 190,000 catalytic converter containers annually.
There are at least three North American makers of catalytic converter panels: Infrared Technologies, CIS-CAN Industries Ltd.
have become victims of catalytic converter theft since 2006, when the rise in global commodity prices made automobile catalytic converters, which filter exhaust fumes using precious metals such as platinum, the target of a new type of vehicle accessory crime.
com/research/qgfznm/automotive) has announced the addition of the "Automotive Catalytic Converter Market by Type (TWC, SCR, DOC, LNT and LNC), by Region (North America, Europe, Asia-Oceania, and RoW), by Material (Platinum, Palladium, Rhodium, & Others) - Global Forecast & Analysis to 2019" report to their offering.
Det Insp Jim Griffiths from KirKlees CID said: "I would urge anyone who is offered a catalytic converter to contact police.
Or they can mark their catalytic converter - etching the part and spraying with heat-resistant paint.
They have been bailed pending further inquiries and officers are keen to hear from anyone who may have had a catalytic converter stolen from their Mercedes to come forward.