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100-595: Michael Bannon, a wealthy but bored businessman and candymaker, issues the code word "Gumball" to his fellow automobile enthusiasts, who gather in a garage in New York City to embark on a coast-to-coast race "with no catalytic converter and no 55-mile-per-hour speed limit" in the shortest amount of time. There is only one rule: "There are no rules". Their longtime nemesis, Los Angeles Police Department Lieutenant Roscoe, who has been trying for years to arrest Bannon and his group, has flown in specially to attempt to shut down

200-585: A computerized closed-loop feedback fuel injection system using one or more oxygen sensors (also known as Lambda Sonds or sensors). Other variants combined three-way converters with carburetors equipped with feedback mixture control were used. An unregulated three-way converter features the same chemical processes but without the oxygen sensor, which meant higher NO x emissions, particularly under partial loads. These were low-cost solutions, typically used for retrofitting to older cars or for smaller, cheaper cars. Three-way converters are effective when

300-512: A reagent such as ammonia to reduce the NO x into nitrogen and water. Ammonia is supplied to the catalyst system by the injection of urea into the exhaust, which then undergoes thermal decomposition and hydrolysis into ammonia. The urea solution is also referred to as diesel exhaust fluid (DEF). Diesel exhaust contains relatively high levels of particulate matter. Catalytic converters remove only 20–40% of PM so particulates are cleaned up by

400-420: A catalytic combustor for gas turbines in the early 1970s, allowing combustion without significant formation of nitrogen oxides and carbon monoxide. Four-way catalytic converters have also been developed which also remove particulates from engine exhaust; since most of these particulates are unburned hydrocarbons, they can be burned to convert them into carbon dioxide. The catalytic converter's construction

500-454: A catalytic converter for any reason other than its direct and immediate replacement. Nevertheless, some vehicle owners remove or "gut" the catalytic converter on their vehicle. In such cases, the converter may be replaced by a welded-in section of ordinary pipe or a flanged "test pipe", ostensibly meant to check if the converter is clogged by comparing how the engine runs with and without the converter. This facilitates temporary reinstallation of

600-637: A catalytic converter was patented by Eugene Houdry , a French mechanical engineer. Houdry was an expert in catalytic oil refining, having invented the catalytic cracking process that all modern refining is based on today. Houdry moved to the United States in 1930 to live near the refineries in the Philadelphia area and develop his catalytic refining process. When the results of early studies of smog in Los Angeles were published, Houdry became concerned about

700-408: A common housing; however, in some instances, they may be housed separately. A three-way catalytic converter does three simultaneous tasks: Reduction of nitrogen oxides to nitrogen (N 2 ) Oxidation of carbon, hydrocarbons, and carbon monoxide to carbon dioxide These three reactions occur most efficiently when the catalytic converter receives exhaust from an engine running slightly above

800-622: A federal criminal offense. NOx In atmospheric chemistry , NO x is shorthand for nitric oxide ( NO ) and nitrogen dioxide ( NO 2 ), the nitrogen oxides that are most relevant for air pollution . These gases contribute to the formation of smog and acid rain , as well as affecting tropospheric ozone . NO x gases are usually produced from the reaction between nitrogen and oxygen during combustion of fuels, such as hydrocarbons , in air; especially at high temperatures, such as in car engines. In areas of high motor vehicle traffic, such as in large cities,

900-468: A head gasket leak, can also cause high unburned hydrocarbons. Emissions regulations vary considerably from jurisdiction to jurisdiction. Most automobile spark-ignition engines in North America have been fitted with catalytic converters since 1975, and the technology used in non-automotive applications is generally based on automotive technology. In many jurisdictions, it is illegal to remove or disable

1000-492: A limit of phosphorus concentration in engine oils was adopted in the API SM and ILSAC GF-4 specifications. Depending on the contaminant, catalyst poisoning can sometimes be reversed by running the engine under a very heavy load for an extended period of time. The increased exhaust temperature can sometimes vaporize or sublimate the contaminant, removing it from the catalytic surface. However, removal of lead deposits in this manner

1100-533: A molecular species that is required to carry away energy from the exothermic reaction 2 . Equation 4 relates the concentrations of NO x and ozone, and is known as the Leighton relationship . The time τ {\displaystyle \tau } that is needed to reach a steady state among NO x and ozone is dominated by reaction ( 3 ), which reverses reactions ( 1 )+( 2 ): for mixing ratio of NO, [NO] = 10 part per billion (ppb),

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1200-460: A power station boiler , during the combustion of a mixture of air and fuel, and naturally in a lightning flash. In atmospheric chemistry , the term NO x refers to the total concentration of NO and NO 2 since the conversion between these two species is rapid in the stratosphere and troposphere. During daylight hours, these concentrations together with that of ozone are in steady state , also known as photostationary state (PSS);

1300-690: A pre-cat, a small catalytic converter upstream of the main catalytic converter which heats up faster on vehicle start up, reducing the emissions associated with cold starts. A pre-cat is most commonly used by an auto manufacturer when trying to attain the Ultra Low Emissions Vehicle (ULEV) rating, such as on the Toyota MR2 Roadster. Catalytic converters have proven to be reliable and effective in reducing noxious tailpipe emissions. However, they also have some shortcomings in use, and also adverse environmental effects in production: Because of

1400-405: A precisely controlled air-fuel mixture that quickly and continually cycles between lean and rich combustion. Oxygen sensors monitor the exhaust oxygen content before and after the catalytic converter, and the engine control unit uses this information to adjust the fuel injection so as to prevent the first ( NO x reduction) catalyst from becoming oxygen-loaded, while simultaneously ensuring

1500-475: A ratio greater than or equal to the stoichiometric combustion requirement. Water Injection technology, whereby water is introduced into the combustion chamber, is also becoming an important means of NO x reduction through increased efficiency in the overall combustion process. Alternatively, the water (e.g. 10 to 50%) is emulsified into the fuel oil before the injection and combustion. This emulsification can either be made in-line (unstabilized) just before

1600-654: A soot trap or diesel particulate filter (DPF). In the U.S., all on-road light, medium, and heavy-duty diesel-powered vehicles built after 1 January 2007, are subject to diesel particulate emission limits, and so are equipped with a 2-way catalytic converter and a diesel particulate filter. As long as the engine was manufactured before 1 January 2007, the vehicle is not required to have the DPF system. This led to an inventory runup by engine manufacturers in late 2006 so they could continue selling pre-DPF vehicles well into 2007. For lean-burn spark-ignition engines, an oxidation catalyst

1700-447: A source of NO x over the ocean. Then, photolysis of NO 2 leads to the formation of ozone and the further formation of hydroxyl radicals (·OH) through ozone photolysis. Since the major sink of methane in the atmosphere is by reaction with OH radicals, the NO x emissions from ship travel may lead to a net global cooling. However, NO x in the atmosphere may undergo dry or wet deposition and return to land in

1800-568: A special formulation of diesel fuel to produce less NO x relative to diesel fuel used in the other 49 states. This has been deemed necessary by the California Air Resources Board (CARB) to offset the combination of vehicle congestion, warm temperatures, extensive sunlight, PM, and topography that all contribute to the formation of ozone and smog. CARB has established a special regulation for Alternative Diesel Fuels to ensure that any new fuels, including biodiesel, coming into

1900-485: A third molecule required to stabilize the addition product. Nitric acid ( HNO 3 ) is highly soluble in liquid water in aerosol particles or cloud drops. NO 2 also reacts with ozone to form nitrate radical During the daytime, NO 3 is quickly photolyzed back to NO 2 , but at night it can react with a second NO 2 to form dinitrogen pentoxide . N 2 O 5 reacts rapidly with liquid water (in aerosol particles or cloud drops, but not in

2000-551: A tradeoff exists as high temperature combustion produces less PM or soot and results in greater power and fuel efficiency . Selective catalytic reduction (SCR) and selective non-catalytic reduction (SNCR) reduce post combustion NO x by reacting the exhaust with urea or ammonia to produce nitrogen and water. SCR is now being used in ships, diesel trucks and in some diesel cars. The use of exhaust gas recirculation and catalytic converters in motor vehicle engines have significantly reduced vehicular emissions . NO x

2100-446: Is an exhaust emission control device which converts toxic gases and pollutants in exhaust gas from an internal combustion engine into less-toxic pollutants by catalyzing a redox reaction . Catalytic converters are usually used with internal combustion engines fueled by gasoline or diesel , including lean-burn engines, and sometimes on kerosene heaters and stoves. The first widespread introduction of catalytic converters

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2200-439: Is as follows: Upon failure, a catalytic converter can be recycled into scrap . The precious metals inside the converter, including platinum, palladium, and rhodium, are extracted. Catalytic converters require a temperature of 400 °C (750 °F) to operate effectively. Therefore, they are placed as close to the engine as possible, or one or more smaller catalytic converters (known as "pre-cats") are placed immediately after

2300-609: Is associated with a number of factors such as combustion temperature. As such, it can be observed that the vehicle drive cycle, or the load on the engine have more significant impact on NO x emissions than the type of fuel used. This may be especially true for modern, clean diesel vehicles that continuously monitor engine operation electronically and actively control engine parameters and exhaust system operations to limit NO x emission to less than 0.2 g/km. Low-temperature combustion or LTC technology may help reduce thermal formation of NO x during combustion, however

2400-563: Is associated with the combustion of nitrogen present in the feed material of cement rotary kilns, at between 300 °C and 800 °C, where it is considered a minor contributor. Thermal NO x refers to NO x formed through high temperature oxidation of the diatomic nitrogen found in combustion air. The formation rate is primarily a function of temperature and the residence time of nitrogen at that temperature. At high temperatures, usually above 1300 °C (2600 °F), molecular nitrogen ( N 2 ) and oxygen ( O 2 ) in

2500-616: Is emitted during its application, it is then reacted in atmosphere to form nitrogen oxides. This third source is attributed to the reaction of atmospheric nitrogen, N 2 , with radicals such as C, CH, and CH 2 fragments derived from fuel, rather than thermal or fuel processes. Occurring in the earliest stage of combustion, this results in the formation of fixed species of nitrogen such as NH ( nitrogen monohydride ), NCN ( diradical cyano nitrene ), HCN ( hydrogen cyanide ), H 2 CN ( dihydrogen cyanide ) and CN ( cyano radical) which can oxidize to NO. In fuels that contain nitrogen,

2600-430: Is highly temperature dependent, is recognized as the most relevant source when combusting natural gas. Fuel NO x tends to dominate during the combustion of fuels, such as coal, which have a significant nitrogen content, particularly when burned in combustors designed to minimise thermal NO x . The contribution of prompt NO x is normally considered negligible. A fourth source, called feed NO x

2700-438: Is intensifying global warming. There are also other indirect effects of NO x that can either increase or decrease the greenhouse effect. First of all, through the reaction of NO with HO 2 · radicals, OH radicals are recycled, which oxidize methane molecules, meaning NO x emissions can counter the effect of greenhouse gases. For instance, ship traffic emits a great amount of NO x which provides

2800-462: Is permitted and a rich mixture is commanded to increase power and prevent exhaust gas temperature from exceeding design limits. This presents a challenge for control system and catalyst design. During such operations, large amounts of unburnt HC are produced by the engine, well beyond the capacity of the catalyst to release oxygen. The surface of the catalyst quickly becomes saturated with HC. When returning to lower power output and leaner air–fuel ratios,

2900-591: Is reduced to nitrite, then NO, then N 2 O and finally nitrogen. Through these processes, NO x is emitted to the atmosphere. A recent study conducted by the University of California Davis found that adding nitrogen fertilizer to soil in California is contributing 25 percent or more to state-wide NO x pollution levels. When nitrogen fertilizer is added to the soil, excess ammonium and nitrate not used by plants can be converted to NO by microorganisms in

3000-407: Is used in the same manner as in a diesel engine. Emissions from lean burn spark ignition engines are very similar to emissions from a diesel compression ignition engine. Many vehicles have a close-coupled catalytic converter located near the engine's exhaust manifold . The converter heats up quickly, due to its exposure to the very hot exhaust gases, allowing it to reduce undesirable emissions during

3100-495: Is usually in response to government regulation, either through environmental regulation or through health and safety regulations. Catalytic converter prototypes were first designed in France at the end of the 19th century, when only a few thousand "oil cars" were on the roads; these prototypes had inert clay-based materials coated with platinum , rhodium , and palladium and sealed into a double metallic cylinder. A few decades later,

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3200-404: Is usually not possible because of lead's high boiling point. Any condition that causes abnormally high levels of unburned hydrocarbons (raw or partially burnt fuel or oils) to reach the converter will tend to significantly elevate its temperature bringing the risk of a meltdown of the substrate and resultant catalytic deactivation and severe exhaust restriction. These conditions include failure of

3300-651: The NO z compounds produced from the oxidation of NO x which include nitric acid , nitrous acid (HONO), dinitrogen pentoxide ( N 2 O 5 ), peroxyacetyl nitrate (PAN), alkyl nitrates ( RONO 2 ), peroxyalkyl nitrates ( ROONO 2 ), the nitrate radical ( NO 3 ), and peroxynitric acid ( HNO 4 ). Because of energy limitations, oxygen and nitrogen do not react at ambient temperatures. But at high temperatures, they undergo an endothermic reaction producing various oxides of nitrogen. Such temperatures arise inside an internal combustion engine or

3400-599: The European Union and the United Kingdom since January 1, 1993 in order to comply with the Euro 1 emission standards . Faulty catalytic converters as well as undamaged early types of converters can restrict the flow of exhaust, which negatively affects vehicle performance and fuel economy. Modern catalytic converters do not significantly restrict exhaust flow. A 2006 test on a 1999 Honda Civic, for example, showed that removing

3500-484: The U.S. Environmental Protection Agency 's new exhaust emissions regulations, most gasoline-powered vehicles manufactured from 1975 onwards are equipped with catalytic converters. Early catalytic converters were "two-way", combining oxygen with carbon monoxide (CO) and unburned hydrocarbons (HC, chemical compounds in fuel of the form C m H n ) to produce carbon dioxide (CO 2 ) and water (H 2 O). These stringent emission control regulations also resulted in

3600-404: The alternator , wiring or fuel lines, with potentially dangerous consequences. In 2023, bipartisan legislation to combat catalytic converter theft was introduced in the U.S. Senate . The Preventing Auto Recycling Thefts Act (PART Act) would mandate catalytic converters in new vehicles to come with traceable identification numbers. Additionally, the legislation would make catalytic converter theft

3700-510: The stoichiometric point. For gasoline combustion, this ratio is between 14.6 and 14.8 parts air to one part fuel, by weight. The ratio for autogas (or liquefied petroleum gas LPG), natural gas , and ethanol fuels can vary significantly for each, notably so with oxygenated or alcohol based fuels, with E85 requiring approximately 34% more fuel, requiring modified fuel system tuning and components when using those fuels. Engines fitted with regulated 3-way catalytic converters are equipped with

3800-407: The U.S. added catalytic systems to their vehicles to meet federal emissions requirements. Two techniques have been developed for the catalytic reduction of NO x emissions under lean exhaust conditions, selective catalytic reduction (SCR) and the NO x adsorber . Instead of precious metal-containing NO x absorbers, most manufacturers selected base-metal SCR systems that use

3900-455: The air pump, which led to the development of the three-way catalytic converter. The two-way catalytic converter also continued to be used on certain, lower-cost cars in some markets such as Europe, where NO x emissions were not universally regulated until the introduction of the Euro 3 emissions standard in 2000. The three-way catalytic converters have the additional advantage of controlling

4000-459: The air. Elevated production of NO x from lightning depends on the season and geographic location. The occurrence of lightning is more common over land near the equator in the inter-tropical convergence zone (ITCZ) during summer months. This area migrates slightly as seasons change. NO x production from lightning can be observed through satellite observations. Scientists Ott et al. estimated that each flash of lightning on average in

4100-444: The air–fuel mixture is brought back to slightly rich, at a small penalty in CO and HC oxidation efficiency, and the cycle repeats. Efficiency is improved when this oscillation around the stoichiometric point is small and carefully controlled. Closed-loop control under light to moderate load is accomplished by using one or more oxygen sensors in the exhaust system. When oxygen is detected by

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4200-468: The car. Vehicles fitted with catalytic converters emit most of their total pollution during the first five minutes of engine operation; for example, before the catalytic converter has warmed up sufficiently to be fully effective. In the early 2000s it became common to place the catalyst converter right next to the exhaust manifold, close to the engine, for much quicker warm-up. In 1995, Alpina introduced an electrically heated catalyst. Called "E-KAT", it

4300-479: The catalyst at reducing NO x is good, and the production of NO x by the engine decreases. To maintain catalyst efficiency, the air–fuel ratio must stay close to stoichiometric and not remain rich or lean for too long. Closed-loop engine control systems are used for effective operation of three-way catalytic converters because of this continuous rich-lean balance required for effective NO x reduction and HC+CO oxidation. The control system allows

4400-412: The catalyst to release oxygen during slightly rich operating conditions, which oxidizes CO and HC under conditions that also favor the reduction of NOx. Before the stored oxygen is depleted, the control system shifts the air–fuel ratio to become slightly lean, improving HC and CO oxidation while storing additional oxygen in the catalyst material, at a small penalty in NO x reduction efficiency. Then

4500-435: The combustion air dissociate into their atomic states and participate in a series of reactions. The three principal reactions (the extended Zel'dovich mechanism ) producing thermal NO x are: All three reactions are reversible. Zeldovich was the first to suggest the importance of the first two reactions. The last reaction of atomic nitrogen with the hydroxyl radical , HO, was added by Lavoie, Heywood and Keck to

4600-416: The combustion of the char portion of the fuels. This reaction occurs much more slowly than the volatile phase. Only around 20% of the char nitrogen is ultimately emitted as NO x , since much of the NO x that forms during this process is reduced to nitrogen by the char, which is nearly pure carbon. Nitrogen oxides are released during manufacturing of nitrogen fertilizers. Though nitrous oxide

4700-411: The concentration of ozone and peroxide compounds, especially peroxyacetyl nitrate (PAN). Children, people with lung diseases such as asthma , and people who work or exercise outside are particularly susceptible to adverse effects of smog such as damage to lung tissue and reduction in lung function. NO 2 is further oxidized in the gas phase during daytime by reaction with OH where M denotes

4800-520: The control system must prevent excessive oxygen from reaching the catalyst too quickly, as this will rapidly burn the HC in the already hot catalyst, potentially exceeding the design temperature limit of the catalyst. Excessive catalyst temperature can prematurely age the catalyst, reducing its efficiency before reaching its design lifetime. Excessive catalyst temperature can also be caused by cylinder misfire, which continuously flows unburnt HC combined with oxygen to

4900-409: The conversion of HC and CO is very efficient due to the available oxygen, oxidizing to H 2 O and CO 2 . Slightly rich of stoichiometric, the production of CO and unburnt HC by the engine starts to increase dramatically, available oxygen decreases, and the efficiency of the catalyst for oxidizing CO and HC decreases significantly, especially as stored oxygen becomes depleted. However, the efficiency of

5000-850: The converter in order to pass an emission test. In the United States, it is a violation of Section 203(a)(3)(A) of the 1990 amended Clean Air Act for a vehicle repair shop to remove a converter from a vehicle, or cause a converter to be removed from a vehicle, except in order to replace it with another converter, and Section 203(a)(3)(B) makes it illegal for any person to sell or to install any part that would bypass, defeat, or render inoperative any emission control system, device, or design element. Vehicles without functioning catalytic converters generally fail emission inspections. The automotive aftermarket supplies high-flow converters for vehicles with upgraded engines, or whose owners prefer an exhaust system with larger-than-stock capacity. xxx Catalytic converters have been mandatory on all new gasoline cars sold in

5100-601: The countryside and in suburbs, while in central London and on major roads NO emissions are able to "mop up" ozone to form NO 2 and oxygen. NO x also readily reacts with common organic chemicals, and even ozone, to form a wide variety of toxic products: nitroarenes , nitrosamines and also the nitrate radical some of which may cause DNA mutations . Recently another pathway, via NO x , to ozone has been found that predominantly occurs in coastal areas via formation of nitryl chloride when NO x comes into contact with salt mist. The direct effect of

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5200-487: The eastern United States can expect to see increases in NO x and in turn, changes in the types of trees which predominate. Due to human activity and climate change , the maples , sassafras , and tulip poplar have been pushing out the beneficial oak , beech , and hickory . The team determined that the first three tree species, maples, sassafras, and tulip poplar, are associated with ammonia-oxidizing bacteria known to "emit reactive nitrogen from soil." By contrast,

5300-522: The emission of NO x has positive contribution to the greenhouse effect. Instead of reacting with ozone in Reaction 3, NO can also react with HO 2 · and organic peroxyradicals ( RO 2 · ) and thus increase the concentration of ozone. Once the concentration of NO x exceeds a certain level, atmospheric reactions result in net ozone formation. Since tropospheric ozone can absorb infrared radiation, this indirect effect of NO x

5400-605: The emission of nitric oxide (NO) and nitrogen dioxide (NO 2 ) (both together abbreviated with NO x and not to be confused with nitrous oxide (N 2 O) ). NO x are precursors to acid rain and smog . Since 1981, the three-way (oxidation-reduction) catalytic converters have been used in vehicle emission control systems in the United States and Canada; many other countries have also adopted stringent vehicle emission regulations that in effect require three-way converters on gasoline-powered vehicles. The reduction and oxidation catalysts are typically contained in

5500-427: The engine is operated within a narrow band of air–fuel ratios near the stoichiometric point. Total conversion efficiency falls very rapidly when the engine is operated outside of this band. Slightly lean of stoichiometric, the exhaust gases from the engine contain excess oxygen, the production of NO x by the engine increases, and the efficiency of the catalyst at reducing NO x falls off rapidly. However,

5600-432: The engine warm-up period. This is achieved by burning off the excess hydrocarbons which result from the extra-rich mixture required for a cold start. When catalytic converters were first introduced, most vehicles used carburetors that provided a relatively rich air-fuel ratio . Oxygen (O 2 ) levels in the exhaust stream were therefore generally insufficient for the catalytic reaction to occur efficiently. Most designs of

5700-578: The exhaust manifold. A 2-way (or "oxidation", sometimes called an "oxi-cat") catalytic converter has two simultaneous tasks: The two-way catalytic converter is widely used on diesel engines to reduce hydrocarbon and carbon monoxide emissions. They were also used on gasoline engines in American and Canadian automobile markets until 1981. Because of their inability to control oxides of nitrogen , manufacturers briefly installed twin catalyst systems, with an NO x reducing, rhodium/platinum catalyst ahead of

5800-533: The external location and the use of valuable precious metals including platinum , palladium and rhodium , catalytic converters are a target for thieves. The problem is especially common among late-model pickup trucks and truck-based SUVs , because of their high ground clearance and easily removed bolt-on catalytic converters. Welded-on converters are also at risk of theft, as they can be easily cut off. The Toyota Prius catalytic converters are also targets for thieves. The catalytic converters of hybrids need more of

5900-405: The extreme heating and cooling within a lightning strike. This causes stable molecules such as N 2 and O 2 to convert into significant amounts of NO similar to the process that occurs during high temperature fuel combustion. NO x from lightning can become oxidized to produce nitric acid ( HNO 3 ), this can be precipitated out as acid rain or deposited onto particles in

6000-653: The finishers celebrate their arrival and the defeated Roscoe sulks off to one side – until a fleet of police cars and tow trucks, summoned by Roscoe, arrive to impound the Gumball vehicles. Roscoe had contrived a plan to see to it that all of them were guaranteed to be illegally parked once the post-race party in the parking lot ran past 11 p.m. Bannon congratulates Roscoe on his final victory (final because Roscoe, who has been after Bannon and Smith since they were in high school, has reached mandatory retirement age). Contemplating how they will all return home without cars, he again utters

6100-680: The first moving car into moving tractor-trailer stunt later to become a trademark of Knight Rider , the typical sequence of workers carrying a large glass window only to have it shattered by a speeding vehicle, and a race in the Los Angeles River at the same location where Greased Lightning would defeat the Scorpions' Mercury in Grease . The race ends at the Queen Mary in Long Beach , California where

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6200-670: The form of HNO 3 / NO − 3 . Through this way, the deposition leads to nitrogen fertilization and the subsequent formation of nitrous oxide ( N 2 O ) in soil, which is another greenhouse gas. In conclusion, considering several direct and indirect effects, NO x emissions have a negative contribution to global warming. NO x in the atmosphere is removed through several pathways. During daytime, NO 2 reacts with hydroxyl radicals (·OH) and forms nitric acid ( HNO 3 ), which can easily be removed by dry and wet deposition. Organic peroxyradicals ( RO 2 · ) can also react with NO and NO 2 and result in

6300-790: The formation of organic nitrates . These are ultimately broken down to inorganic nitrate, which is a useful nutrient for plants. During nighttime, NO 2 and NO can form nitrous acid (HONO) through surface-catalyzed reaction. Although the reaction is relatively slow, it is an important reaction in urban areas. In addition, the nitrate radical ( NO 3 ) is formed by the reaction between NO 2 and ozone. At night, NO 3 further reacts with NO 2 and establishes an equilibrium reaction with dinitrogen pentoxide ( N 2 O 5 ). Via heterogeneous reaction, N 2 O 5 reacts with water vapor or liquid water and forms nitric acid ( HNO 3 ). As mentioned above, nitric acid can be removed through wet and dry deposition and this results in

6400-411: The gas phase) to form HNO 3 , These are thought to be the principal pathways for formation of nitric acid in the atmosphere. This nitric acid contributes to acid rain or may deposit to soil, where it makes nitrate , which is of use to growing plants. The aqueous phase reaction is too slow to be of any significance in the atmosphere. Nitric oxide is produced during thunderstorms due to

6500-417: The gasoline additive MMT ), and silicon , which can enter the exhaust stream if the engine has a leak that allows coolant into the combustion chamber. Phosphorus is another catalyst contaminant. Although phosphorus is no longer used in gasoline, it (and zinc , another low-level catalyst contaminant) was widely used in engine oil antiwear additives such as zinc dithiophosphate (ZDDP). Beginning in 2004,

6600-416: The hot catalyst, burning in the catalyst and increasing its temperature. Unwanted reactions result in the formation of hydrogen sulfide and ammonia , which poison catalysts. Nickel or manganese is sometimes added to the washcoat to limit hydrogen-sulfide emissions. Sulfur-free or low-sulfur fuels eliminate or minimize problems with hydrogen sulfide. For compression-ignition (i.e., diesel ) engines,

6700-673: The incidence of prompt NO x is comparatively small and it is generally only of interest for the most exacting emission targets. There is strong evidence that NO x respiratory exposure can trigger and exacerbate existing asthma symptoms, and may even lead to the development of asthma over longer periods of time. It has also been associated with heart disease, diabetes, birth outcomes, and all-cause mortality, but these nonrespiratory effects are less well-established. NO x reacts with ammonia , moisture, and other compounds to form nitric acid vapor and related particles. NO x reacts with volatile organic compounds in

6800-408: The initial stages of combustion. During the release and before the oxidation of the volatiles, nitrogen reacts to form several intermediaries which are then oxidized into NO. If the volatiles evolve into a reducing atmosphere, the nitrogen evolved can readily be made to form nitrogen gas, rather than NO x . The second pathway involves the combustion of nitrogen contained in the char matrix during

6900-455: The market do not substantially increase NO x emissions. The reduction of NO x emissions is one of the most important challenges for advances in vehicle technology. While diesel vehicles sold in the US since 2010 are dramatically cleaner than previous diesel vehicles, urban areas continue to seek more ways to reduce the formation of smog and ozone. NO x formation during combustion

7000-404: The mechanism and makes a significant contribution to the formation of thermal NO x . It is estimated that transportation fuels cause 54% of the anthropogenic (i.e. human-caused) NO x . The major source of NO x production from nitrogen-bearing fuels such as certain coals and oil, is the conversion of fuel bound nitrogen to NO x during combustion. During combustion,

7100-596: The most commonly used catalytic converter is the diesel oxidation catalyst (DOC). DOCs contain palladium or platinum supported on alumina . This catalyst converts particulate matter (PM), hydrocarbons, and carbon monoxide to carbon dioxide and water. These converters often operate at 90 percent efficiency, virtually eliminating diesel odor and helping reduce visible particulates. These catalysts are ineffective for NO x , so NO x emissions from diesel engines are controlled by exhaust gas recirculation (EGR). In 2010, most light-duty diesel manufacturers in

7200-427: The nitrogen bound in the fuel is released as a free radical and ultimately forms free N 2 , or NO. Fuel can contribute as much as 50% of total NO x emissions through the combusting oil and as much as 80% through the combusting of coal Although the complete mechanism is not fully understood, there are two primary pathways of formation. The first involves the oxidation of volatile nitrogen species during

7300-448: The nitrogen oxides emitted can be a significant source of air pollution. NO x gases are also produced naturally by lightning . NO x does not include nitrous oxide ( N 2 O ), a fairly inert oxide of nitrogen that contributes less severely to air pollution, notwithstanding its involvement in ozone depletion and high global warming potential . NO y is the class of compounds comprising NO x and

7400-438: The number of lightning strikes occurring on Earth. Therefore, space weather can be a major driving force of lightning-produced atmospheric NO x . Atmospheric constituents such as nitrogen oxides can be stratified vertically in the atmosphere. Ott noted that the lightning-produced NO x is typically found at altitudes greater than 5 km, while combustion and biogenic (soil) NO x are typically found near

7500-582: The oxidation reactions. An upstream air injection point, ahead of the catalytic converter, is also sometimes present to provide additional oxygen only during the engine warm up period. This causes unburned fuel to ignite in the exhaust tract, thereby preventing it reaching the catalytic converter at all. This technique reduces the engine runtime needed for the catalytic converter to reach its "light-off" or operating temperature . Most newer vehicles have electronic fuel injection systems, and do not require air injection systems in their exhausts. Instead, they provide

7600-404: The precious metals to work properly compared to conventional internal combustion vehicles because they do not get as hot as those installed on conventional vehicles, since the combustion engines of hybrids only run part of the time. Pipecutters are often used to quietly remove the converter but other tools such as a portable reciprocating saw can damage other components of the car, such as

7700-518: The presence of sunlight to form ozone . Ozone can cause adverse effects such as damage to lung tissue and reduction in lung function mostly in susceptible populations (children, elderly, asthmatics). Ozone can be transported by wind currents and cause health impacts far from the original sources. The American Lung Association estimates that nearly 50 percent of United States inhabitants live in counties that are not in ozone compliance. In South East England, ground level ozone pollution tends to be highest in

7800-622: The race. He is unsuccessful, and the race begins early the next morning in spite of his momentary interference. Most of the film is devoted to the adventures of the various driving teams and Roscoe's ineffectual attempts to apprehend them. A number of running gags ensue – the Jaguar that will not start (and never even makes it off the starting line); the silent (and somewhat-psychotic) motorcyclist Lapchik's numerous mishaps; Italian race driver Franco Bertollini's frequent detours to seduce beautiful women – as well as some stunts and driving sequences, including

7900-403: The ratio of NO to NO 2 is determined by the intensity of sunshine (which converts NO 2 to NO) and the concentration of ozone (which reacts with NO to again form NO 2 ). In other words, the concentration of ozone in the atmosphere is determined by the ratio of these two species. The symbol M {\displaystyle {\ce {M}}} represents a "third body",

8000-659: The removal of NO x from the atmosphere. Biodiesel and its blends in general are known to reduce harmful tailpipe emissions such as: carbon monoxide ; particulate matter (PM), otherwise known as soot ; and unburned hydrocarbon emissions. While earlier studies suggested biodiesel could sometimes decrease NO x and sometimes increase NO x emissions, subsequent investigation has shown that blends of up to 20% biodiesel in USEPA-approved diesel fuel have no significant impact on NO x emissions compared with regular diesel . The state of California uses

8100-414: The removal of the antiknock agent tetraethyl lead from automotive gasoline, to reduce lead in the air. Lead and its compounds are catalyst poisons and foul catalytic converters by coating the catalyst's surface. Requiring the removal of lead allowed the use of catalytic converters to meet the other emission standards in the regulations. To lower harmful NO x emissions, a twin-catalyst system

8200-417: The role of smokestack exhaust and automobile exhaust in air pollution and founded a company called Oxy-Catalyst. Houdry first developed catalytic converters for smokestacks , called "cats" for short, and later developed catalytic converters for warehouse forklifts that used low grade, unleaded gasoline. In the mid-1950s, he began research to develop catalytic converters for gasoline engines used on cars and

8300-474: The second (HC and CO oxidation) catalyst is sufficiently oxygen-saturated. Catalyst poisoning occurs when the catalytic converter is exposed to exhaust containing substances that coat the working surfaces, so that they cannot contact and react with the exhaust. The most notable contaminant is lead , so vehicles equipped with catalytic converters can run only on unleaded fuel. Other common catalyst poisons include sulfur , manganese (originating primarily from

8400-491: The second three tree species, oak, beech and hickory, are associated with microbes that "absorb reactive nitrogen oxides," and thus can have a positive impact on the nitrogen oxide component of air quality. Nitrogen oxide release from forest soils is expected to be highest in Indiana, Illinois, Michigan, Kentucky and Ohio. The three primary sources of NO x in combustion processes: Thermal NO x formation, which

8500-468: The sensing of the changed air–fuel ratio by the sensor, as well as the sigmoidal response of the oxygen sensors. Typical control systems are designed to rapidly sweep the air–fuel ratio such that it oscillates slightly around the stoichiometric point, staying near the optimal efficiency point while managing the levels of stored oxygen and unburnt HC. Closed loop control is often not used during high load/maximum power operation, when an increase in emissions

8600-418: The sensor, the air–fuel ratio is lean of stoichiometric, and when oxygen is not detected, it is rich. The control system adjusts the rate of fuel being injected into the engine based on this signal to keep the air–fuel ratio near the stoichiometric point in order to maximize the catalyst conversion efficiency. The control algorithm is also affected by the time delay between the adjustment of the fuel flow rate and

8700-543: The several mid-latitude and subtropical thunderstorms studied turned 7 kg (15 lb) of nitrogen into chemically reactive NO x . With 1.4 billion lightning flashes per year, multiplied by 7 kilograms per lightning strike, they estimated the total amount of NO x produced by lightning per year is 8.6 million tonnes. However, NO x emissions resulting from fossil fuel combustion are estimated at 28.5 million tonnes. A recent discovery indicated that cosmic ray and solar flares can significantly influence

8800-482: The soil, which escapes into the air. NO x is a precursor for smog formation which is already a known issue for the state of California. In addition to contributing to smog, when nitrogen fertilizer is added to the soil and the excess is released in the form of NO, or leached as nitrate this can be a costly process for the farming industry. A 2018 study by the Indiana University determined that forests in

8900-427: The sources at near surface elevation (where it can cause the most significant health effects). Agricultural fertilization and the use of nitrogen fixing plants also contribute to atmospheric NO x , by promoting nitrogen fixation by microorganisms. The nitrification process transforms ammonia into nitrate. Denitrification is basically the reverse process of nitrification. During denitrification, nitrate

9000-400: The stock catalytic converter netted only a 3% increase in maximum horsepower; a new metallic core converter only cost the car 1% horsepower, compared to no converter. Carburetors on pre-1981 vehicles without feedback fuel-air mixture control could easily provide too much fuel to the engine, which could cause the catalytic converter to overheat and potentially ignite flammable materials under

9100-453: The time constant is 40 minutes; for [NO] = 1 ppb, 4 minutes. When NO x and volatile organic compounds (VOCs) react in the presence of sunlight, they form photochemical smog , a significant form of air pollution. The presence of photochemical smog increases during the summer when the incident solar radiation is higher. The emitted hydrocarbons from industrial activities and transportation react with NO x quickly and increase

9200-442: The time therefore included secondary air injection , which injected air into the exhaust stream. This increased the available oxygen, allowing the catalyst to function as intended. Some three-way catalytic converter systems have air injection systems with the air injected between the first ( NO x reduction) and second (HC and CO oxidation) stages of the converter. As in two-way converters, this injected air provides oxygen for

9300-476: The upstream components of the exhaust system (manifold or header assembly and associated clamps susceptible to rust, corrosion or fatigue such as the exhaust manifold splintering after repeated heat cycling), ignition system (e.g., coil packs, primary ignition components, distributor cap, wires, ignition coil and spark plugs) or damaged fuel system components (e.g., fuel injectors, fuel pressure regulator, and associated sensors). Oil and coolant leaks, perhaps caused by

9400-506: The word "Gumball" to the assembled group to indicate a race back to New York. Lapchik, the last contestant to finish the race, roars through the parking lot with a stuck throttle and is launched out into the water. Most of the filming took place in Arizona. Opening scenes of the race were filmed in downtown New York City early on a Sunday morning on closed roads (including Broadway and Park Avenue). The George Washington Bridge and Lincoln Tunnel

9500-422: Was awarded United States Patent 2,742,437 for his work. Catalytic converters were further developed by a series of engineers including Carl D. Keith , John J. Mooney , Antonio Eleazar, and Phillip Messina at Engelhard Corporation, creating the first production catalytic converter in 1973. The first widespread introduction of catalytic converters was in the United States automobile market. To comply with

9600-521: Was developed in the 1970s – this added a separate (rhodium/platinum) catalyst which reduced NO x ahead of the air pump, after which a two-way catalytic converter (palladium/platinum) removed HC and CO. This cumbersome and expensive system was soon made redundant, after it was noted that under some conditions the initial catalyst also removed HC and CO. This led to the development of the three-way catalyst, made possible by electronics and engine management developments. William C. Pfefferle developed

9700-1158: Was in the United States automobile market. To comply with the U.S. Environmental Protection Agency 's stricter regulation of exhaust emissions, most gasoline-powered vehicles starting with the 1975 model year are equipped with catalytic converters. These "two-way" converters combine oxygen with carbon monoxide (CO) and unburned hydrocarbons (HC) to produce carbon dioxide (CO 2 ) and water (H 2 O). Although two-way converters on gasoline engines were rendered obsolete in 1981 by "three-way" converters that also reduce oxides of nitrogen ( NO x ), they are still used on lean-burn engines to oxidize particulate matter and hydrocarbon emissions (including diesel engines, which typically use lean combustion), as three-way-converters require fuel-rich or stoichiometric combustion to successfully reduce NO x . Although catalytic converters are most commonly applied to exhaust systems in automobiles, they are also used on electrical generators , forklifts , mining equipment, trucks , buses , locomotives , motorcycles , and on ships. They are even used on some wood stoves to control emissions. This

9800-532: Was the main focus of the Volkswagen emissions violations . Other technologies such as flameless oxidation ( FLOX ) and staged combustion significantly reduce thermal NO x in industrial processes. Bowin low NO x technology is a hybrid of staged-premixed-radiant combustion technology with major surface combustion preceded by minor radiant combustion. In the Bowin burner, air and fuel gas are premixed at

9900-674: Was used for the exit from New York into New Jersey. The final duel between the Cobra and Ferrari was filmed at (and in) the Los Angeles River and the closing scene was shot at the Queen Mary in Long Beach. Additional filming was done in the City of Orange, California, specifically around the downtown Plaza area (approximately 1:07 - 1:10). The film holds a rating of 29% on Rotten Tomatoes from 14 reviews. Catalytic converter A catalytic converter

10000-536: Was used in Alpina's B12 5,7 E-KAT based on the BMW 750i . Heating coils inside the catalytic converter assemblies are electrified just after the engine is started, bringing the catalyst up to operating temperature very quickly to qualify the vehicle for low emission vehicle (LEV) designation. BMW later introduced the same heated catalyst, developed jointly by Emitec, Alpina, and BMW, in its 750i in 1999. Some vehicles contain

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