Catalytic Converters The term Catalytic Converter covers the stainless steel box mounted in the exhaust system. Inside the cover is the catalyst, a ceramic or metallic base with an active coating incorporating alumina, ceria and other oxides and combinations of the precious metals platinum, palladium and rhodium. The base can be protected from vibration and shock by a resilient ceramic or metallic ‘mat’img”>images/news/icons/source.gif[/img”> News source: About Auto Repair The main by-products of combustion are: Nitrogen gas (N2): Our atmosphere is 78 percent nitrogen gas, and most of this passes right through the car engine. Carbon Dioxide (CO2): A harmless, odorless gas composed of carbon and oxygen. It is also a greenhouse gas that contributes to global warming. Water vapor (H2O): Another by-product of combustion. Sponsored LinksScrap Converter BuyersTop prices paid for any quantity of used catalytic converters.[url”>www.adccatalyticconverters.comBuy a Catalytic ConverterCatalytic Converters on Sale now We Match or Beat any Price![url”>www.autopartswarehouse.comFree Catalytic ConverterMagnaflow Universal Catalytic Converter. Submit Offers.automotive-offer.comThe hydrogen in the fuel bonds with the oxygen in the air. These three emissions are mostly harmless, although carbon dioxide emissions are believed to contribute to global warming. However since the combustion process is never perfect, other more harmful emissions are produced in the process. Carbon monoxide (CO): A colorless, odorless gas. It is poisonous and extremely dangerous in confined areas, building up slowly to toxic levels without warning if adequate ventilation is not available. Hydrocarbons or volatile organic compounds (VOCs): Any chemical compound made up of hydrogen and carbon. Oxides of nitrogen (NOx): Chemical compounds of nitrogen, they combine with hydrocarbons to produce smog. These are the three main regulated emissions, and also the ones that catalytic converters are designed to reduce. Catalytic converters can either be an oxidation or three-way type. Oxidation catalysts convert carbon monoxide (CO) and hydrocarbons (HC) to carbon dioxide (CO2) and water, but have little effect on nitrogen oxides (NOx) and particulate matter. Three-way catalysts operate in a closed-loop system together with a lambda, or oxygen, sensor to regulate the air/fuel ratio on Fuel engines. The catalyst can then at the same time oxidize CO and HC to CO2 and water while reducing NOx to nitrogen. Most cars today are equipped with a three-way catalytic converter. The term Three-way refers to the three emissions it helps to reduce, carbon monoxide, hydrocarbons or volatile organic compounds (VOCs) and NOx molecules. The converter uses two different types of catalysts, a reduction catalyst and an oxidization catalyst. Both types consist of a base structure coated with a catalyst such as platinum, rhodium and/or palladium. The scheme is to create a structure that exposes the maximum surface area of the catalyst to the exhaust flow, while also minimizing the amount of catalyst required. The inside of the catalytic converter is a honeycomb set of passageways or small ceramic beads coated with catalysts. A chemical reaction takes place to make the pollutants less harmful. There are many passages for the exhaust gases to flow, to allow for the maximum amount of surface area for the hot gases to pass. In order to reduce emissions, modern car engines carefully control the amount of fuel they burn. They try to keep the air-to-fuel ratio very close to the stoichiometric point, which is the calculated ideal ratio of air to fuel. Theoretically, at this ratio, all of the fuel will be burned using all of the oxygen in the air. For Fuel engines the stoichiometric ratio is about 14.7:1. This means that for every pound of Fuel, 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.The Reduction Catalyst: The reduction catalyst is the first stage of the catalytic converter. 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.Oxidation Catalysts: Palladium (Pd) and platinum (Pt) metals in very small amounts convert the hydrocarbons of unburned Fuel and carbon monoxide to carbon dioxide and water. This catalyst aids the reaction of the CO and hydrocarbons with the remaining oxygen in the exhaust gas. But where did this oxygen come from?The third stage is a control system that monitors the exhaust stream, and uses this information to regulate the air/fuel mixture. There is an oxygen sensor mounted in front of the catalytic converter, meaning it is between the engine and the converter. The O2 sensor tells the engine ECU how much oxygen is in the exhaust.The ECU can increase or decrease the amount of oxygen in the exhaust by adjusting the air/fuel mixture. In this way the ECU can make sure that the engine is running as close to the stoichiometric point, and also ensure there is enough oxygen in the exhaust to allow the oxidization catalyst to burn the unburned hydrocarbons and CO.The catalytic converter does an efficient job of reducing the vehicle emissions, but there are ways it can be improved. Sponsored LinksBuy a Catalytic ConverterCatalytic Converters on Sale now We Match or Beat any Price![url”>www.autopartswarehouse.comCatalytic ConvertersOEM and Aftermarket Converters VW, Audi, Honda, Volvo and others.[url”>www.performancecatalytic.comFree Catalytic ConverterMagnaflow Universal Catalytic Converter. Submit Offers.automotive-offer.comOne of the biggest drawbacks is that it only works at a fairly high temperature. When you start your car cold, the catalytic converter does next to nothing to reduce the vehicle emissions. The catalytic converter does an efficient job of reducing the vehicle emissions, but there are ways it can be improved. One of the biggest drawbacks is that it only works at a fairly high temperature. When you start your car cold, the catalytic converter does next to nothing to reduce the vehicle emissions. The simplest solution is to move the catalytic converter closer to the engine. This allows hot exhaust gases to get to the converter and it heat it up faster. This could also reduce the life of the converter by exposing it to extremely high temperatures. Most carmakers position the converter under the front seats, just far enough from the engine to keep the temperature at a level that will not damage it.The simplest solution is to move the catalytic converter closer to the engine. This allows hot exhaust gases to get to the converter and it heat it up faster. This could also reduce the life of the converter by exposing it to extremely high temperatures. Most carmakers position the converter under the front seats, just far enough from the engine to keep the temperature at a level that will not damage it.Why do converters go bad? There are two ways a converter can fail, it can become clogged or it can be poisoned. When catalytic converters fail they normally clog up with debris and block the flow of exhaust gas from getting out of the system. This will cause tremendous performance problems. In extreme cases it will prevent the vehicle from starting at all. Most of the time it just limits engine performance by choking the flow through the engine. So how do you check a catalytic converter without removing it from the car?? Sometimes an indication that a converter is clogged is that you don’t go any faster when you push the gas pedal down. In addition there usually is a noticeable drop in fuel economy associated with a clogged catalytic converter. A totally clogged converter will cause the engine to die because of the increased backpressure. There is no way for anyone to actually see a clog in a converter. Usually the only way to tell if a catalytic converter is clogged is to remove it and check the change in engine performance. When a mechanic suspects a clogged converter they may remove the O2 sensor from the exhaust pipe and see if there is a change in performance. A catalytic converter relies on receiving the proper mix of exhaust gases at the proper temperature. Some engine oil additives or engine problems that cause the mixture or the temperature of the exhaust gases to change reduce the effectiveness and life of the catalytic converter. Leaded Fuel and the over-use of fuel additives can shorten the life of a catalytic converter considerably. Even some gasket sealers and cements can poison a converter. A catalytic converter can also fail because of certain other factors. A number of problems could occur to the catalytic converter as the result of an engine that is out of tune. Any time an engine is operating outside proper specifications, unnecessary wear and damage may be caused to the catalytic converter as well as the engine itself. The damage is often the result of an incorrect air/fuel mixture, incorrect timing, or misfiring spark plugs. Any of these conditions could lead to a catalytic converter failure or worse.Fouled plugs can cause unburned fuel to overheat the converter and melt the catalyst to a solid mass. If the O2 Sensor is not functioning properly it will give the ECU incorrect readings of exhaust gasses. The faulty sensor can cause an excessively rich or excessively lean condition. If the mixture is too rich, the catalyst can melt down. If the mixture is too lean, the converter is unable to convert the hydrocarbons into safe elements.Oil or antifreeze entering the exhaust system can block the air passages by creating heavy carbon soot that coats the catalyst. These heavy carbon deposits will cause two problems. First, the carbon deposits prevent the catalytic converter from reducing harmful emission in the exhaust flow. And second, the carbon deposits clog the pores in the ceramic catalyst and block exhaust flow, increasing backpressure and causing heat and exhaust to back up into the engine compartment. Sponsored LinksBuy a Catalytic ConverterCatalytic Converters on Sale now We Match or Beat any Price![url”>www.autopartswarehouse.comFree Catalytic ConverterMagnaflow Universal Catalytic Converter. Submit Offers.automotive-offer.comCatalytic Converters?Brief and Straightforward Guide to Catalytic Converterswisegeek.comYour engine may actually draw burnt exhaust gasses back into the combustion chamber and dilute the efficiency of the next burn cycle. The result is a loss of power and overheated engine components.Catalytic converters can be physically damaged as well. The catalyst contained inside a catalytic converter is made from a lightweight, thin-walled, fragile material. It is protected by a dense, insulating mat. This mat holds the catalyst in place and provides moderate protection against damage. Broken support hangers can cause the converter to bounce around and the result can be breakage of the mat. Rocks or other road debris can also hit the converter, causing the internal mat to break also. Off road vehicles often suffer this type of converter failure. Once this mat starts to break up, it will collect in the smaller passages and clog the converter.The catalytic converter should last the lifetime of the vehicle it is installed in. if it does fail, it is most often a symptom of another problem. This problem must be identified and repaired or the new converter will fail in the same manner. You can keep it running well by keeping the ignition system in top shape and to prevent any unburnt fuel from entering the catalytic converter.Here is an important safety reminder: Do not park your car over tall grass or piles of dry leaves. Your cars perfectly running catalytic converter gets very hot… enough to start fires!