100-410: Disi may refer to: Defence & International Security Institute , a non-profit, non-partisan, semi-public institution dedicated to informing the public about science and policy issues affecting international security and defence. Direct Injection Spark Ignition , an engine fuel management technology by Mazda Emilio Disi , an Argentine actor Disi
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
300-515: 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
600-656: 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
800-442: A direct-injected engine refers to how the fuel is distributed throughout the combustion chamber: In the homogeneous charge mode , the engine operates on a homogeneous air/fuel mixture ( λ = 1 {\displaystyle \lambda =1} ), meaning, that there is an (almost) perfect mixture of fuel and air in the cylinder. The fuel is injected at the very beginning of the intake stroke in order to give injected fuel
900-475: 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
1000-496: 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
1100-545: A major cause of pollution for the region. Three-way catalyst A catalytic converter 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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#17327727956491200-710: 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
1300-405: 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
1400-418: A richer air-fuel ratio at higher loads. In theory, a stratified charge mode can further improve fuel efficiency and reduce exhaust emissions, however, in practice, the stratified charge concept has not proved to have significant efficiency advantages over a conventional homogeneous charge concept, but due to its inherent lean burn, more nitrogen oxides are formed, which sometimes require a NOx adsorber in
1500-657: 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
1600-421: A spark-plug (due to a lack of fuel), the charge needs to be stratified (e. g. a small zone of fuel/air mixture around the spark plug needs to be created). To achieve such a charge, a stratified charge engine injects the fuel during the latter stages of the compression stroke. A "swirl cavity" in the top of the piston is often used to direct the fuel into the zone surrounding the spark plug . This technique enables
1700-512: A special swirl or tumble movement in order to direct the fuel towards the spark plug. This swirl or tumble movement must be retained for a relatively long period of time, so that all of the fuel is getting pushed towards the spark plug. This however reduces the engine's charging efficiency and thus power output. In practice, a combination of air-guided and wall-guided injection is used. There exists only one engine that only relies on air-guided injection. In engines with spray-guided direct injection,
1800-565: A study published in January 2020 in the journal Environmental Science and Technology , a team of researchers at the University of Georgia (USA) predicted that the increase in black carbon emissions from GDI-powered vehicles will increase climate warming in urban areas of the U.S. by an amount that significantly exceeds the cooling associated with a reduction in CO 2 . The researchers also believe
1900-438: A very high air ratio at its edges. The fuel can only be ignited in between these two "zones". Ignition takes place almost immediately after injection to increase engine efficiency. The spark plug must be placed in such a way, that it is exactly in the zone where the mixture is ignitable. This means that the production tolerances need to be very low, because only very little misalignment can result in drastic combustion decline. Also,
2000-427: Is a mixture formation system for internal combustion engines that run on gasoline (petrol), where fuel is injected into the combustion chamber . This is distinct from manifold injection systems, which inject fuel into the intake manifold (inlet manifold). The use of GDI can help increase engine efficiency and specific power output as well as reduce exhaust emissions. The first GDI engine to reach production
2100-410: Is achieved in two-stroke GDI engines by injecting oil into the crankcase, resulting in a lower oil consumption than the older method of injecting oil mixed with fuel into the crankcase. Two types of GDI are used in two-strokes: low-pressure air-assisted, and high-pressure. The low-pressure systems—as used on the 1992 Aprilia SR50 motor scooter—uses a crankshaft-driven air compressor to inject air into
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#17327727956492200-569: Is an improved version of the Ficht system, which was released in 2003 and won an EPA Clean Air Excellence Award in 2004. Envirofit International , an American non-profit organisation, has developed direct injection retrofit kits for two-stroke motorcycles (using technology developed by Orbital Corporation Limited ) in a project to reduce air pollution in Southeast Asia. The 100-million two-stroke taxis and motorcycles in Southeast Asia are
2300-439: 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
2400-406: Is more limited for GDI, since there is a shorter period of time available to inject the required quantity of fuel. In manifold injection (as well as carburetors and throttle-body fuel injection), fuel can be added to the intake air mixture at any time. However a GDI engine is limited to injecting fuel during the intake and compression phases. This becomes a restriction at high engine speeds (RPM), when
2500-462: 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,
2600-575: Is the 10th chakra (group) of 6 musical scales, into which the seventy two basic scales, or Melakarta rāgas, of Carnatic music are classified. Disi aquifer is a vital source of water in the arid southern region of Jordan. The aquifer is shared with the Kingdom of Saudi Arabia. In the past this non renewable source was used to irrigate wheat in the Saudi desert in largely in the Tabuk region. More recent
2700-407: 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
2800-499: 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,
2900-404: 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
3000-617: 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
3100-484: 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
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3200-404: 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
3300-510: 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
3400-470: The 1970s, the United States manufacturers American Motors Corporation and Ford developed prototype mechanical GDI systems called Straticharge and Programmed Combustion (PROCO) respectively. Neither of these systems reached production. The 1996 Japanese-market Mitsubishi Galant was the first mass-produced car to use a GDI engine, when a GDI version of the Mitsubishi 4G93 inline-four engine
3500-451: 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
3600-459: 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
3700-566: The air, as would be the case in a conventional Otto cycle engine, but is instead injected during the compression stroke a little in advance of the spark. Hesselman engines could use a wide variety of fuels, including gasoline, but generally ran on conventional diesel fuels. During World War II, most of the German aircraft engines used GDI, such as the BMW 801 radial engine, the German inverted V12 Daimler-Benz DB 601 , DB 603 and DB 605 engines, and
3800-399: 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
3900-468: 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
4000-479: 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
4100-412: 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
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4200-523: 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
4300-409: 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
4400-850: 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
4500-528: The cylinder head. A low-pressure injector then sprays fuel into the combustion chamber, where it vaporizes as it mixes with the compressed air. A high-pressure GDI system was developed by German company Ficht GmbH in the 1990s and introduced for marine engines by Outboard Marine Corporation (OMC) in 1997, in order to meet stricter emissions regulations. However, the engines had reliability problems and OMC declared bankruptcy in December 2000. The Evinrude E-Tec
4600-444: The cylinder, which can force the ignitable parts of the mixture so far away from the spark plug, that it cannot ignite the air/fuel mixture anymore. Other devices which are used to complement GDI in creating a stratified charge include variable valve timing , variable valve lift , and variable length intake manifold . Also, exhaust gas recirculation can be used to reduce the high nitrogen oxide (NOx) emissions that can result from
4700-400: The desired distribution of fuel throughout the combustion chamber are either spray-guided , air-guided , or wall-guided injection. The trend in recent years is towards spray-guided injection, since it currently results in a higher fuel efficiency. In engines with wall-guided injection, the distance between spark plug and injection nozzle is relatively high. In order to get the fuel close to
4800-413: The distance between spark plug and injection nozzle is relatively high. However, unlike in wall-guided injection engines, the fuel does not get in contact with (relatively) cold engine parts such as cylinder wall and piston. Instead of spraying the fuel against a swirl cavity, in air-guided injection engines the fuel is guided towards the spark plug solely by the intake air. The intake air must therefore have
4900-425: The distance between spark plug and injection nozzle is relatively low. Both the injection nozzle and spark plug are located in between the cylinder's valves. The fuel is injected during the latter stages of the compression stroke, causing very quick (and inhomogeneous) mixture formation. This results in large fuel stratification gradients, meaning that there is a cloud of fuel with a very low air ratio in its centre, and
5000-458: The duration of each combustion cycle is shorter. To overcome this limitation, some GDI engines (such as the Toyota 2GR-FSE V6 and Volkswagen EA888 I4 engines) also have a set of manifold fuel injectors to provide additional fuel at high RPM. These manifold fuel injectors also assist in cleaning carbon deposits from the intake system. Gasoline does not provide the same level of lubrication for
5100-605: 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
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#17327727956495200-427: 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,
5300-432: 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
5400-418: The engine, therefore Junkers developed a GDI system to prevent this issue. A demonstration of this prototype engine to aviation officials was performed shortly before development ceased due to the end of World War I. The Hesselman engine is a hybrid engine design which was in production by various manufacturers from 1925 to 1951. In a Hesselman engine fuel is not injected during the suction stroke along with
5500-583: 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
5600-513: The exhaust system to meet emissions regulations. The use of NOx adsorbers can require low sulphur fuels, since sulphur prevents NOx adsorbers from functioning properly. GDI engines with stratified fuel injection can also produce higher quantities of particulate matter than manifold injected engines, sometimes requiring particulate filters in the exhaust (similar to a diesel particulate filter ) in order to meet vehicle emissions regulations. Therefore several European car manufacturers have abandoned
5700-533: 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
5800-524: The first successful prototype in 1894. An early prototype of a GDI engine was built in Germany in 1916 for the Junkers airplane. The engine was initially designed as a diesel engine, however it switched to being designed for gasoline when the German ministry of war decreed that aircraft engines must run on either gasoline or benzene. Being a crankcase-compression two-stroke design, a misfire could destroy
5900-465: The following years. The Mitsubishi GDI technology was also licensed by Peugeot, Citroën, Hyundai, Volvo and Volkswagen. The 2005 Toyota 2GR-FSE V6 engine was the first to combine both direct and indirect injection. The system (called "D-4S") uses two fuel injectors per cylinder: a traditional manifold fuel injector (low pressure) and a direct fuel injector (high-pressure) and is used in most Toyota engines. In Formula One racing, direct injection
6000-443: The fuel cools down the spark plug, immediately before it is exposed to combustion heat. Thus, the spark plug needs to be able to withstand thermal shocks very well. At low piston (and engine) speeds, the relative air/fuel velocity is low, which can cause fuel to not vaporise properly, resulting in a very rich mixture. Rich mixtures do not combust properly, and cause carbon build-up. At high piston speeds, fuel gets spread further within
6100-494: The fuel on the relatively cold piston cool down so much, that they cannot combust properly. When switching from low engine load to medium engine load (and thus advancing the injection timing), some parts of the fuel can end up getting injected behind the swirl cavity, also resulting in incomplete combustion. Engines with wall-guided direct injection can therefore suffer from high hydrocarbon emissions. Like in engines with wall-guided injection, in engines with air-guided injection,
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#17327727956496200-417: 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,
6300-401: The gasoline fuel separately pressurised to 1000psi and admitted into the cylinder 'at the moment of highest compression' by a small rotary valve, with simultaneous ignition by a spark plug and trembler coil allowing sparking to continue throughout the combustion phase. The fuel being injected was described as being in vapour phase having been heated by the engine cylinder. The pressure of the fuel
6400-491: The government of Jordan embarked on the Disi Water Conveyance Project to provide drinking water to the largest population in the capital Amman. Dorsal intercalated segment instability deformity of the hand Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title Disi . If an internal link led you here, you may wish to change
6500-597: The homogeneous charge mode. The stratified charge mode creates a small zone of fuel/air mixture around the spark plug, which is surrounded by air in the rest of the cylinder. This results in less fuel being injected into the cylinder, leading to very high overall air-fuel ratios of λ > 8 {\displaystyle \lambda >8} , with mean air-fuel ratios of λ = 3...5 {\displaystyle \lambda =3...5} at medium load, and λ = 1 {\displaystyle \lambda =1} at full load. Ideally,
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,
6700-574: The injector components as diesel, which sometimes becomes a limiting factor in the injection pressures used by GDI engines. The injection pressure of a GDI engine is typically limited to approximately 20 MPa (2.9 ksi), to prevent excessive wear on the injectors. While this technology is credited with boosting fuel efficiency and reducing CO 2 emissions, GDI engines produce more black carbon aerosols than traditional port fuel injection engines. A strong absorber of solar radiation, black carbon possesses significant climate-warming properties. In
6800-443: The intake and exhaust ports open during the exhaust stroke, in order to improve the flushing of exhaust gases from the cylinder. This results in some of the fuel/air mixture entering the cylinder and then exiting the cylinder, unburned, through the exhaust port. With direct injection, only air (and usually some oil) comes from the crankcase, and fuel is not injected until the piston rises and all ports are closed. Crankcase lubrication
6900-463: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Disi&oldid=1190622894 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Direct Injection Spark Ignition Gasoline direct injection ( GDI ), also known as petrol direct injection ( PDI ),
7000-562: The misleading title of Forced Induction Engine whereas it was only the admission of the fuel that was forced. He revealed details of his prototype engine early in 1912, and the design was further developed by the large scale engine builder F. E. Baker Ltd during 1912 and the results displayed on their stand at the Olympia Motor Cycle show in November 1912. The engine was a high compression four-stroke motorcycle engine, with
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
7200-439: The most time to mix with the air, so that a homogeneous air/fuel mixture is formed. This mode allows using a conventional three-way catalyst for exhaust gas treatment. Compared with manifold injection, the fuel efficiency is only very slightly increased, but the specific power output is better, which is why the homogeneous mode is useful for so-called engine downsizing . Most direct-injected passenger car petrol engines use
7300-582: 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
7400-404: 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
7500-414: 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
7600-417: 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
7700-474: 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
7800-468: 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
7900-418: 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
8000-415: The shift from traditional port fuel injection (PFI) engines to the use of GDI technology will nearly double the premature mortality rate associated with vehicle emissions, from 855 deaths annually in the United States to 1,599. They estimate the annual social cost of these premature deaths at $ 5.95 billion. One of the early inventors trying gasoline direct injection was Dr Archibald Low who gave his engine
8100-510: The similar-layout Junkers Jumo 210 G, Jumo 211 and Jumo 213 inverted V12 engines. Allied aircraft engines that used GDI fuel injection systems were the Soviet Union Shvetsov ASh-82 FNV radial engine and the American 54.9 litre displacement Wright R-3350 Duplex Cyclone 18-cylinder radial engine. The German company Bosch had been developing a mechanical GDI system for cars since the 1930s and in 1952 it
8200-516: The spark plug, it is sprayed against a swirl cavity on top of the piston (as seen in the picture of the Ford EcoBoost engine on the right), which guides the fuel towards the spark plug. Special swirl or tumble air intake ports aid this process. The injection timing depends upon the piston speed, therefore, at higher piston speeds, the injection timing, and ignition timing need to be advanced very precisely. At low engine temperatures, some parts of
8300-400: 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
8400-476: The stratified charge concept or never used it in the first place, such as the 2000 Renault 2.0 IDE petrol engine ( F5R ), which never came with a stratified charge mode, or the 2009 BMW N55 and 2017 Mercedes-Benz M256 engines dropping the stratified charge mode used by their predecessors. The Volkswagen Group had used fuel stratified injection in naturally aspirated engines labelled FSI , however, these engines have received an engine control unit update to disable
8500-434: The stratified charge mode. Turbocharged Volkswagen engines labelled TFSI and TSI have always used the homogeneous mode. Like the latter VW engines, newer direct injected petrol engines (from 2017 onwards) usually also use the more conventional homogeneous charge mode, in conjunction with variable valve timing, to obtain good efficiency. Stratified charge concepts have mostly been abandoned. Common techniques for creating
8600-434: The throttle valve remains open as much as possible to avoid throttling losses. The torque is then set solely by means of quality torque controlling, meaning that only the amount of injected fuel, but not the amount of intake air is manipulated in order to set the engine's torque. Stratified charge mode also keeps the flame away from the cylinder walls, reducing the thermal losses. Since mixtures too lean cannot be ignited with
8700-442: 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
8800-617: The ultra lean combustion. Gasoline direct injection does not have the valve cleaning action that is provided when fuel is introduced to the engine upstream of the cylinder. In non-GDI engines, the gasoline traveling through the intake port acts as a cleaning agent for contamination, such as atomized oil. The lack of a cleaning action can cause increased carbon deposits in GDI engines. Third party manufacturers sell oil catch tanks which are supposed to prevent or reduce those carbon deposits. The ability to produce peak power at high engine speeds (RPM)
8900-476: 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
9000-515: The use of ultra-lean mixtures that would be impossible with carburetors or conventional manifold fuel injection. The stratified charge mode (also called "ultra lean-burn" mode) is used at low loads, in order to reduce fuel consumption and exhaust emissions. However, the stratified charge mode is disabled for higher loads, with the engine switching to the homogeneous mode with a stoichiometric air-fuel ratio of λ = 1 {\displaystyle \lambda =1} for moderate loads and
9100-426: Was automatically added to the fuel mixture, obviating the need for owners to mix their own two-stroke fuel blend. The 1955 Mercedes-Benz 300SL also used an early Bosch mechanical GDI system, therefore becoming the first four-stroke engine to use GDI. Up until the mid-2010s, most fuel-injected cars used manifold injection, making it quite unusual that these early cars used an arguably more advanced GDI system. During
9200-422: 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
9300-521: 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
9400-1158: 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
9500-489: Was introduced in 1925 for a low-compression truck engine. Several German cars used a Bosch mechanical GDI system in the 1950s, however usage of the technology remained rare until an electronic GDI system was introduced in 1996 by Mitsubishi for mass-produced cars. GDI has seen rapid adoption by the automotive industry in recent years, increasing in the United States from 2.3% of production for model year 2008 vehicles to approximately 50% for model year 2016. The 'charge mode' of
9600-481: Was introduced on the two-stroke engines in the Goliath GP700 and Gutbrod Superior. This system was basically a high-pressure diesel direct-injection pump with an intake throttle valve set up. These engines gave good performance and had up to 30% less fuel consumption over the carburetor version, primarily under low engine loads. An added benefit of the system was having a separate tank for the engine oil which
9700-518: Was introduced. It was subsequently brought to Europe in 1997 in the Carisma . It also developed the first six-cylinder GDI engine, the Mitsubishi 6G74 V6 engine, in 1997. Mitsubishi applied this technology widely, producing over one million GDI engines in four families by 2001. Although in use for many years, on 11 September 2001 MMC claimed a trademark for the acronym 'GDI'. Several other Japanese and European manufacturers introduced GDI engines in
9800-437: Was made compulsory for the 2014 season , with regulation 5.10.2 stating: "There may only be one direct injector per cylinder and no injectors are permitted upstream of the intake valves or downstream of the exhaust valves." There are additional benefits of GDI for two-stroke engines , relating to scavenging of the exhaust gases and lubrication of the crankcase. The scavenging aspect is that most two-stroke engines have both
9900-399: Was regulated at the fuel pump, and the amount of fuel admitted was controlled by mechanical means at the rotary admission valve. It seems this radical design wasn't taken further by F. E. Baker. Although direct injection has only become commonly used in gasoline engines since 2000, diesel engines have used fuel directly injected into the combustion chamber (or a pre-combustion chamber) since
10000-543: 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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