Efficient engines and catalytic converters
Catalytic converters by Chris Woodford.
Catalytic converter efficiency calculation
Although cats turn most nitrogen oxides into nitrogen and oxygen, they also produce small amounts of nitrous oxide N2O in the process, a greenhouse gas that's over times more potent than carbon dioxide. During a long oxygen-rich period the generated NOx is stored in the barium component. Ammonia is supplied to the catalyst system by the injection of urea into the exhaust, which then undergoes thermal decomposition and hydrolysis into ammonia. Let's take a closer look at these brilliant gadgets and how they work! Chemistry : An Introduction to General, Organic, and Biological Chmi Problems What are the potential hazards of the toxic substances emitted by a car without a catalytic converter? Catalytic converters are used in exhaust systems to provide a site for the oxidation and reduction of toxic by-products like nitrogen oxides, carbon monoxide, and hydrocarbons of fuel into less hazardous substances such as carbon dioxide, water vapor, and nitrogen gas. Even so, while catalytic converters have certainly helped us to tackle short-term air pollution, there are concerns that, when it comes to long-term climate change, they could be making matters worse. Once the catalysts in a catalytic converter heat to an optimal temperature, they begin burning the partially and unburned hydrocarbons that naturally occur in the exhaust. Smog is a pollutant and has adverse effects on children's lungs. This technique reduces the engine runtime needed for the catalytic converter to reach its "light-off" or operating temperature. Why Catalytic Converters are Necessary and Differ from Fuel Catalysts August 30, Why Catalytic converters are necessary is because fossil fuels — particularly gasoline — do not combust efficiently without combustion-enhancing technologies. How a catalytic converter works Before catalytic converters were developed, waste gases made by a car engine blew straight down the exhaust tailpipe and into the atmosphere. Odorless and colorless, this gas does not have many useful functions in everyday processes.
Unwanted reactions[ edit ] Unwanted reactions can occur in the three-way catalyst, such as the formation of odoriferous hydrogen sulfide and ammonia. Additionally, laboratory tests indicate that in this new configuration, the metals degrade by approximately four percent afterkm 62, miles of use — by contrast, over the same distance, the metals in a regular converter degrade by about 35 percent.
In general, engines fitted with 3-way catalytic converters are equipped with a computerized closed-loop feedback fuel injection system using one or more oxygen sensors ,[ citation needed ] though early in the deployment of three-way converters, carburetors equipped with feedback mixture control were used.
Some, less-effective converters carry out only the second two oxidation reactions, so they're called two-way catalytic converters.
Catalytic converter function
They were also used on gasoline engines in American- and Canadian-market automobiles until Lead does not ignite nor combust, so the compression resistance of gasoline increases when supplemented with lead. No more than grams of these precious metals are used in a single converter. Although cats turn most nitrogen oxides into nitrogen and oxygen, they also produce small amounts of nitrous oxide N2O in the process, a greenhouse gas that's over times more potent than carbon dioxide. Early on in the manufacturing history of gasoline engines, engineers realized the importance of compression ratio. Let's take a closer look at these brilliant gadgets and how they work! Vehicles equipped with OBD-II diagnostic systems are designed to alert the driver to a misfire condition by means of illuminating the "check engine" light on the dashboard, or flashing it if the current misfire conditions are severe enough to potentially damage the catalytic converter. And, since the compression ratios of engines dropped, so did gasoline engine fuel efficiency. Not only does the failure of a gasoline engine to completely burn gasoline means the engines are less fuel efficient, unburned and partially burned hydrocarbons result in many of the most toxic and dangerous emissions. When catalytic converters were first introduced, most vehicles used carburetors that provided a relatively rich air-fuel ratio. Because of their inability to control oxides of nitrogen , they were superseded by three-way converters. It's essentially a set of concentric metal tubes blue through which the exhaust gases flow. The difference is the three-way containing an oxygen sensor. A fuel catalyst, on the other hand, both reduces emissions and increases fuel efficiency.
A catalytic converter is a post-combustion emissions reduction device. Unlike diesel engines, gasoline engines are not compression engines. It is most frequently used in catalytic converters to clean auto emissions in conjunction with its fellow PMG metals Platinum and Palladium.
It's essentially a set of concentric metal tubes blue through which the exhaust gases flow. Three-way[ edit ] Three-way catalytic converters TWC have the additional advantage of controlling the emission of nitric oxide NO and nitrogen dioxide NO2 both together abbreviated with NO x and not to be confused with nitrous oxide N2Owhich are precursors to acid rain and smog.
This breaks up nitrogen oxides into nitrogen and oxygen gases which are harmless, because they already exist in the air around us.
Catalytic converter material
The keys to combustion efficiency are compression ratio and air-to-fuel ratio. Oxygen O2 levels in the exhaust stream were therefore generally insufficient for the catalytic reaction to occur efficiently. When catalytic converters were first introduced, most vehicles used carburetors that provided a relatively rich air-fuel ratio. Manganese and silicon: Manganese is primarily found in the organometallic compound MMT methylcyclopentadienyl manganese tricarbonyl. Another commonality between catalytic converters and fuel catalysts is that purpose of both — or at least in part in the case of a fuel catalyst — is to reduce emissions. Athens is one of the world's most traffic-polluted cities. Additionally, laboratory tests indicate that in this new configuration, the metals degrade by approximately four percent after , km 62, miles of use — by contrast, over the same distance, the metals in a regular converter degrade by about 35 percent. For this so-called NOx Storage Reduction NSR catalytic converter the fuel is alternately combusted in the engine under oxygen-rich lean and fuel-rich rich conditions.
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