Manifold injection is a mixture formation system for internal combustion engines with external mixture formation. It is commonly used in engines with spark ignition that use petrol as fuel, such as the Otto engine , and the Wankel engine . In a manifold-injected engine, the fuel is injected into the intake manifold, where it begins forming a combustible air-fuel mixture with the air. As soon as the intake valve opens, the piston starts sucking in the still forming mixture. Usually, this mixture is relatively homogeneous, and, at least in production engines for passenger cars, approximately stoichiometric ; this means that there is an even distribution of fuel and air across the combustion chamber, and enough, but not more air present than what is required for the fuel's complete combustion. The injection timing and measuring of the fuel amount can be controlled either mechanically (by a fuel distributor), or electronically (by an engine control unit ). Since the 1970s and 1980s, manifold injection has been replacing carburettors in passenger cars. However, since the late 1990s, car manufacturers have started using petrol direct injection , which caused a decline in manifold injection installation in newly produced cars.
65-520: MPFI may refer to: Multi-Point Fold Injection Modern Pentathlon Federation of India , an Indian sports federation Max Planck Florida Institute for Neuroscience , a research facility located in Jupiter, Florida Topics referred to by the same term [REDACTED] This disambiguation page lists articles associated with the title MPFI . If an internal link led you here, you may wish to change
130-489: A lambda sensor . Only electronically controlled systems can form the stoichiometric air-fuel mixture precisely enough for a three-way catalyst to work sufficiently, which is why mechanically controlled manifold injection systems such as the Bosch K-Jetronic are now considered obsolete. As the name implies, a single-point injected (SPI) engine only has a single fuel injector. It is usually installed right behind
195-456: A continuously injecting system, the fuel is injected continuously, thus, there are no operating modes. In intermittently injecting systems however, there are usually four different operating modes. In a simultaneously intermittently injecting system, there is one single, fixed injection timing for all cylinders. Therefore, the injection timing is ideal only for some cylinders; there is always at least one cylinder that has its fuel injected against
260-436: A known technology since the 1960s, but has long been considered inferior to carburettors, because it requires an injection pump, and is thus more complicated. Only with the availability of inexpensive digital engine control units ( ECUs ) in the 1980s did single-point injection become a reasonable option for passenger cars. Usually, intermittently injecting, low injection pressure (70...100 kPa) systems were used that allowed
325-440: A mechanic "analogue" engine map was used. This allowed injecting fuel intermittently, and relatively precisely. Typically, such injection pumps have a three-dimensional cam that depicts the engine map. Depending on the throttle position, the three-dimensional cam is moved axially on its shaft. A roller-type pick-up mechanism that is directly connected to the injection pump control rack rides on the three-dimensional cam. Depending upon
390-419: A multi-point injected engine has one fuel injector per cylinder, an electric fuel pump, a fuel distributor, an airflow sensor, and, in modern engines, an engine control unit . The temperatures near the intake valve(s) are rather high, the intake stroke causes intake air swirl, and there is much time for the air-fuel mixture to form. Therefore, the fuel does not require much atomisation. The atomisation quality
455-446: A multi-point injected engine, every cylinder has its own fuel injector, and the fuel injectors are usually installed in close proximity to the intake valve(s). Thus, the injectors inject the fuel through the open intake valve into the cylinder, which should not be confused with direct injection. Certain multi-point injection systems also use tubes with poppet valves fed by a central injector instead of individual injectors. Typically though,
520-406: A petrol-fuelled Otto engine. However, they were not successful. In 1930 Moto Guzzi built the first manifold injected Otto engine for motorcycles, which eventually was the first land vehicle engine with manifold injection. From the 1930s until the 1950s, manifold injections systems were not used in passenger cars, despite the fact that such systems existed. This was because the carburettor proved to be
585-458: A proper air-fuel mixture is formed, the injection control system needs to know how much air is sucked into the engine, so it can determine how much fuel has to be injected accordingly. In modern systems, an air-mass meter that is built into the throttle body meters the air mass, and sends a signal to the engine control unit, so it can calculate the correct fuel mass. Alternatively, a manifold vacuum sensor can be used. The manifold vacuum sensor signal,
650-613: A simpler and less expensive, yet sufficient mixture formation system that did not need replacing yet. In ca. 1950, Daimler-Benz started development of a petrol direct injection system for their Mercedes-Benz sports cars. For passenger cars however, a manifold injection system was deemed more feasible. Eventually, the Mercedes-Benz W ;128 , W 113 , W 189 , and W 112 passenger cars were equipped with manifold injected Otto engines. From 1951 until 1956, FAG Kugelfischer Georg Schäfer & Co. developed
715-494: A three-way converter. Two-way converters were common until the 1980s, when three-way converters replaced them on most automobile engines. See the catalytic converter article for further details. Evaporative emissions are the result of gasoline vapors escaping from the vehicle's fuel system. Since 1971, all U.S. vehicles have had fully sealed fuel systems that do not vent directly to the atmosphere; mandates for systems of this type appeared contemporaneously in other jurisdictions. In
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#1732787797154780-499: A typical system, vapors from the fuel tank and carburetor bowl vent (on carbureted vehicles) are ducted to canisters containing activated carbon . The vapors are adsorbed within the canister, and during certain engine operational modes fresh air is drawn through the canister, pulling the vapor into the engine, where it burns. Some US states are also using a technology which uses infrared and ultraviolet light to detect emissions while vehicles pass by on public roads, thus eliminating
845-408: Is an injection every half crankshaft rotation, so that at least in some areas of the engine map no fuel is injected against a closed intake valve. This is an improvement over a simultaneously injecting system. However, the fuel evaporation times are still different for each cylinder. In a sequentially injecting system, each fuel injector has a fixed, correctly set, injection timing that is in sync with
910-417: Is both more reliable and more precise than a three-dimensional cam. The engine control circuitry uses the engine map, as well as airflow, throttle valve, crankshaft speed, and intake air temperature sensor data to determine both the amount of injected fuel, and the injection timing. Usually, such systems have a single, pressurised fuel rail, and injection valves that open according to an electric signal sent from
975-462: Is desired, the amount of injected fuel has to be changed along with the intake air throttling. To do so, manifold injection systems have at least one way to measure the amount of air that is currently being sucked into the engine. In mechanically controlled systems with a fuel distributor, a vacuum-driven piston directly connected to the control rack is used, whereas electronically controlled manifold injection systems typically use an airflow sensor , and
1040-457: Is relative to the injection pressure, which means that a relatively low injection pressure (compared with direct injection) is sufficient for multi-point injected engines. A low injection pressure results in a low relative air-fuel velocity, which causes large, and slowly vapourising fuel droplets. Therefore, the injection timing has to be precise to minimise unburnt fuel (and thus HC emissions). Because of this, continuously injecting systems such as
1105-400: Is similar to a single-point injection system. CPFI (used from 1992 to 1995) is a batch-fire system, while CSFI (from 1996) is a sequential system. In manifold injected engines, there are three main methods of metering the fuel, and controlling the injection timing. In early manifold injected engines with fully mechanical injection systems, a gear-, chain- or belt-driven injection pump with
1170-470: Is that the fuel is also injected when the intake valves are closed, but such systems are much simpler and less expensive than mechanical injection systems with engine maps on three-dimensional cams. Only the amount of injected fuel has to be determined, which can be done very easily with a rather simple fuel distributor that is controlled by an intake manifold vacuum-driven airflow sensor. The fuel distributor does not have to create any injection pressure, because
1235-447: Is the study of reducing the emissions produced by motor vehicles , especially internal combustion engines . The primary emissions studied include hydrocarbons, volatile organic compounds, carbon monoxide, carbon dioxide, nitrogen oxides, particulate matter, and sulfur oxides. Starting in the 1950s and 1960s, various regulatory agencies were formed with a primary focus on studying the vehicle emissions and their effects on human health and
1300-593: The American Petroleum Institute the elimination of leaded fuels for 1975 and later model year cars. The production and distribution of unleaded fuel was a major challenge, but it was completed successfully in time for the 1975 model year cars. All modern cars are now equipped with catalytic converters to further reduce vehicle emissions. Leading up to the 1981 model year in the United States, passenger vehicle manufactures were faced with
1365-628: The D-Jetronic . In 1973, Bosch introduced their first self-developed multi-point injection systems, the electronic L-Jetronic , and the mechanical, unpowered K-Jetronic . Their fully digital Motronic system was introduced in 1979. It found widespread use in German luxury saloons. At the same time, most American car manufacturers stuck to electronic single-point injection systems. In the mid-1980s, Bosch upgraded their non-Motronic multi-point injection systems with digital engine control units, creating
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#17327877971541430-628: The Department for Environment, Food and Rural Affairs (DEFRA) and they are still subject to EU regulations. Emissions tests on diesel cars have not been carried out during MOTs in Northern Ireland for 12 years, despite being legally required. It was very important to system designers to meet the emission requirements using a minimum quantity of catalyst material ( platinum and/or palladium ) due to cost and supply issues. The General Motors "Emissions Control Systems Project Center"
1495-550: The natural environment . Emissions that are principal pollutants of concern include: Throughout the 1950s and 1960s, various federal, state and local governments in the United States conducted studies into the numerous sources of air pollution. These studies ultimately attributed a significant portion of air pollution to the automobile, and concluded air pollution is not bounded by local political boundaries. At that time, such minimal emission control regulations as existed in
1560-461: The 1979 model year. California vehicles with 2.5, 2.8 and 3.5 liter engines will have a CLCC system. In 1980 model year, vehicles sold in California and 3.8 and 4.3 liter engines sold federally will have CLCC, and finally in the 1981 model year all passenger cars will have the system. California light and medium duty trucks may also use the c-4 system. While 1979 and 1980 systems are very similar,
1625-664: The 1981 system (2nd generation) will differ in that it may include additional engine control systems (i.e., electronic spark timing, idle speed control, etc.) The Emission Control System under development has been designated C-4.This stands for Computer Controlled Catalytic Converter. The C-4 System encompasses Closed Loop Carburetor Control (CLCC) and Throttle Body Injection (TBI) systems."" Engine efficiency has been steadily improved with improved engine design, more precise ignition timing and electronic ignition , more precise fuel metering , and computerized engine management . Advances in engine and vehicle technology continually reduce
1690-475: The Bosch K-Jetronic are obsolete. Modern multi-point injection systems use electronically controlled intermittent injection instead. From 1992 to 1996 General Motors implemented a system called Central Port Injection or Central Port Fuel Injection. The system uses tubes with poppet valves from a central injector to spray fuel at each intake port rather than the central throttle body . Fuel pressure
1755-606: The EU forms the policy (by setting limits such as the European emission standard ) and the member states decide how to best implement it in their own country. In the United Kingdom, matters concerning environmental policy are "devolved powers" so that some of the constituent countries deal with it separately through their own government bodies set up to deal with environmental issues: However, many UK-wide policies are handled by
1820-734: The KE-Jetronic, and the LH-Jetronic. Volkswagen developed the digital "Digijet" injection system for their "Wasserboxer" water-cooled engines , which evolved into the Volkswagen Digifant system in 1985. Cheap single-point injection systems that worked with either two-way or three-way catalyst converters, such as the Mono-Jetronic introduced in 1987, enabled car manufacturers to economically offer an alternative to carburettors even in their economy cars, which helped
1885-597: The State of California for 1966 model year for cars sold in that state, followed by the United States as a whole in model year 1968. Also in 1966, the first emission test cycle was enacted in the State of California measuring tailpipe emissions in PPM (parts per million). The standards were progressively tightened year by year, as mandated by the EPA. By the 1974 model year, the United States emission standards had tightened such that
1950-561: The U.S. were promulgated at the municipal or, occasionally, the state level. The ineffective local regulations were gradually supplanted by more comprehensive state and federal regulations. By 1967 the State of California created the California Air Resources Board , and in 1970, the federal United States Environmental Protection Agency (EPA) was established. Both agencies, as well as other state agencies, now create and enforce emission regulations for automobiles in
2015-556: The United States. Similar agencies and regulations were contemporaneously developed and implemented in Canada , Western Europe , Australia , and Japan . The first effort at controlling pollution from automobiles was the PCV (positive crankcase ventilation) system. This draws crankcase fumes heavy in unburned hydrocarbons – a precursor to photochemical smog – into the engine's intake tract so they are burned rather than released unburned from
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2080-401: The air/fuel charge to reduce peak combustion chamber temperatures. This, in turn, reduces the formation of NO x . The catalytic converter is a device placed in the exhaust pipe, which converts hydrocarbons, carbon monoxide, and NO x into less harmful gases by using a combination of platinum, palladium and rhodium as catalysts . There are two types of catalytic converter, a two-way and
2145-630: The challenges in its history of meeting new emissions regulations, how to meet the much more restrictive requirements of the Clean Air Act (United States) per the 1977 amendment. For example: to meet this challenge, General Motors created a new "Emissions Control Systems Project Center" (ECS) first located at the AC Spark Plug Engineering Building in Flint, Michigan. Its purpose was to "Have overall responsibility for
2210-408: The closed intake valve(s). This causes fuel evaporation times that are different for each cylinder. Systems with intermittent group injection work similarly to the simultaneously injection systems mentioned earlier, except that they have two or more groups of simultaneously injecting fuel injectors. Typically, a group consists of two fuel injectors. In an engine with two groups of fuel injectors, there
2275-502: The converter supports combustion in the exhaust headpipe, which speeds catalyst warmup and reduces the amount of unburned hydrocarbon emitted from the tailpipe. In the United States and Canada, many engines in 1973 and newer vehicles (1972 and newer in California) have a system that routes a metered amount of exhaust into the intake tract under particular operating conditions. Exhaust neither burns nor supports combustion, so it dilutes
2340-426: The crankcase into the atmosphere. Positive crankcase ventilation was first installed on a widespread basis by law on all new 1961-model cars first sold in California. The following year, New York required it. By 1964, most new cars sold in the U.S. were so equipped, and PCV quickly became standard equipment on all vehicles worldwide. The first legislated exhaust (tailpipe) emission standards were promulgated by
2405-449: The de-tuning techniques used to meet them were seriously reducing engine efficiency and thus increasing fuel usage. The new emission standards for 1975 model year, as well as the increase in fuel usage, forced the invention of the catalytic converter for after-treatment of the exhaust gas. This was not possible with existing leaded gasoline , because the lead residue contaminated the platinum catalyst. In 1972, General Motors proposed to
2470-486: The design and development of the carborated and fuel injected closed loop 3-way catalyst system including related electronic controls, fuel metering, spark control, idle speed control, EGR, etc. currently planned through 1981." In 1990, the Clean Air Act (CAA) was amended to help further regulate harmful vehicle emissions. In the amendment, vehicle fuel regulations became more stringent by limiting how much sulfur
2535-588: The engine control circuitry. The circuitry can either be fully analogue, or digital. Analogue systems such as the Bendix Electrojector were niche systems, and used from the late 1950s until the early 1970s; digital circuitry became available in the late 1970s, and has been used in electronic engine control systems since. One of the first widespread digital engine control units was the Bosch Motronic . In order to mix air and fuel correctly so
2600-403: The engine determines the amount of torque produced. For controlling the amount of mixture, a throttle valve is used, which is why quantity control is also called intake air throttling. Intake air throttling changes the amount of air sucked into the engine, which means that if a stoichiometric ( λ ≈ 1 {\displaystyle \lambda \approx 1} ) air-fuel mixture
2665-547: The environment. As the worlds understanding of vehicle emissions improved, so did the devices used to mitigate their impacts. The regulatory requirements of the Clean Air Act, which was amended many times, greatly restricted acceptable vehicle emissions. With the restrictions, vehicles started being designed more efficiently by utilizing various emission control systems and devices which became more common in vehicles over time. Emissions of many air pollutants have been shown to have variety of negative effects on public health and
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2730-430: The exhaust would finish burning. Air injection is now used to support the catalytic converter 's oxidation reaction, and to reduce emissions when an engine is started from cold. After a cold start, an engine needs an air-fuel mixture richer than what it needs at operating temperature , and the catalytic converter does not function efficiently until it has reached its own operating temperature. The air injected upstream of
2795-467: The extensive spread of manifold injection systems across all passenger car market segments during the 1990s. In 1995, Mitsubishi introduced the first petrol direct injection Otto engine for passenger cars, and the petrol direct injection has been replacing the manifold injection since, but not across all market segments; several newly produced passenger car engines still use multi-point injection. Vehicle emissions control Vehicle emissions control
2860-423: The first two-stroke engine with manifold injection in 1906; the first manifold injected series production four-stroke aircraft engines were built by Wright and Antoinette the same year ( Antoinette 8V ). In 1912, Bosch equipped a watercraft engine with a makeshift injection pump built from an oil pump, but this system did not prove to be reliable. In the 1920s, they attempted to use a Diesel engine injection pump in
2925-416: The fuel is injected with relatively low pressure (70...1470 kPa) into the intake manifold to form a fine fuel vapour. This vapour can then form a combustible mixture with the air, and the mixture is sucked into the cylinder by the piston during the intake stroke. Otto engines use a technique called quantity control for setting the desired engine torque , which means that the amount of mixture sucked into
2990-423: The fuel mass can be corrected according to air pressure, and water temperature. Kugelfischer injection systems also have a mechanical centrifugal crankshaft speed sensor. Multi-point injected systems with mechanical controlling were used until the 1970s. In systems without injection-timing controlling, the fuel is injected continuously, thus, no injection timing is required. The biggest disadvantage of such systems
3055-517: The fuel not only according to firing order, and intake valve opening intervals, but it also allows it to correct cylinder charge irregularities. This system's disadvantage is that it requires cylinder-specific air-mass determination, which makes it more complicated than a sequentially injecting system. The first manifold injection system was designed by Johannes Spiel at Hallesche Maschinenfabrik. Deutz started series production of stationary four-stroke engines with manifold injection in 1898. Grade built
3120-410: The fuel pump already provides pressure sufficient for injection (up to 500 kPa). Therefore, such systems are called "unpowered", and do not need to be driven by a chain or belt, unlike systems with mechanical injection pumps. Also, an engine control unit is not required. "Unpowered" multi-point injection systems without injection-timing controlling such as the Bosch K-Jetronic were commonly used from
3185-458: The link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=MPFI&oldid=1196829223 " Category : Disambiguation pages Hidden categories: Short description is different from Wikidata All article disambiguation pages All disambiguation pages Manifold injection#Multi-point injection There are two different types of manifold injection: In this article,
3250-578: The mechanical Kugelfischer injection system. It was used in many passenger cars, such as the Peugeot 404 (1962), Lancia Flavia iniezione (1965), BMW E10 (1969), Ford Capri RS 2600 (1970), BMW E12 (1973), BMW E20 (1973), and the BMW E26 (1978). In 1957, Bendix Corporation presented the Bendix Electrojector , one of the first electronically controlled manifold injection systems. Bosch built this system under licence, and marketed it from 1967 as
3315-605: The mid-1970s until the early 1990s in passenger cars, although examples had existed earlier, such as the Rochester Ramjet offered on high-performance versions of the Chevrolet small-block engine from 1957 to 1965. Engines with manifold injection, and an electronic engine control unit are often referred to as engines with electronic fuel injection (EFI). Typically, EFI engines have an engine map built into discrete electronic components, such as read-only memory . This
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#17327877971543380-470: The more important update standards are as follows. In 1922, lead was added to gasoline as an antiknock agent. It was not until 1969, nearly five decades later, that research began to show the negative health affects related to lead as a pollutant. Despite the plethora of negative health impacts discovered, no regulatory requirements were implemented to reduce lead levels in gasoline until 1983. Slowly, countries began banning use of lead in gasoline entirely from
3445-516: The need for owners to go to a test center. Invisible light flash detection of exhaust gases is commonly used in metropolitan areas, and becoming more broadly known in Europe. Emission test results from individual vehicles are in many cases compiled to evaluate the emissions performance of various classes of vehicles, the efficacy of the testing program and of various other emission-related regulations (such as changes to fuel formulations) and to model
3510-431: The redesign and tooling costs of these components. However, single-point injection does not allow forming very precise mixtures required for modern emission regulations, and is thus deemed an obsolete technology in passenger cars. Single-point injection was used extensively on American-made passenger cars and light trucks during 1980–1995, and in some European cars in the early and mid-1990s. Single-point injection has been
3575-764: The same country. For example, in the United States, overall responsibility belongs to the EPA, but due to special requirements of the State of California, emissions in California are regulated by the Air Resources Board . In Texas, the Texas Railroad Commission is responsible for regulating emissions from LPG -fueled rich burn engines (but not gasoline-fueled rich burn engines). The European Union has control over regulation of emissions in EU member states; however, many member states have their own government bodies to enforce and implement these regulations in their respective countries. In short,
3640-425: The spark plug firing order, and the intake valve opening. This way, no more fuel is injected against closed intake valves. Cylinder-specific injection means that there are no limitations to the injection timing. The injection control system can set the injection timing for each cylinder individually, and there is no fixed synchronisation between each cylinder's injector. This allows the injection control unit to inject
3705-425: The terms multi-point injection (MPI), and single-point injection (SPI) are used. In an MPI system, there is one fuel injector per cylinder, installed very close to the intake valve(s). In an SPI system, there is only a single fuel injector, usually installed right behind the throttle valve. Modern manifold injection systems are usually MPI systems; SPI systems are now considered obsolete. In a manifold injected engine,
3770-400: The three-dimensional cam's position, it pushes in or out the camshaft-actuated injection pump plungers, which controls both the amount of injected fuel, and the injection timing. The injection plungers both create the injection pressure, and act as the fuel distributors. Usually, there is an additional adjustment rod that is connected to a barometric cell, and a cooling water thermometer, so that
3835-514: The throttle position, and the crankshaft speed can then be used by the engine control unit to calculate the correct amount of fuel. In modern engines, a combination of all these systems is used. Mechanical injection controlling systems as well as unpowered systems typically only have an intake manifold vacuum sensor (a membrane or a sensor plate) that is mechanically connected to the injection pump rack or fuel distributor. Manifold injected engines can use either continuous or intermittent injection. In
3900-481: The throttle valve in the throttle body. Single-point injection was a relatively low-cost way for automakers to reduce exhaust emissions to comply with tightening regulations while providing better "driveability" (easy starting, smooth running, freedom from hesitation) than could be obtained with a carburetor. Many of the carburetor's supporting components - such as the air cleaner, intake manifold, and fuel line routing - could be used with few or no changes. This postponed
3965-453: The toxicity of exhaust leaving the engine, but these alone have generally been proved insufficient to meet emissions goals. Therefore, technologies to detoxify the exhaust are an essential part of emissions control. One of the first-developed exhaust emission control systems is secondary air injection. Originally, this system was used to inject air into the engine's exhaust ports to provide oxygen so unburned and partially burned hydrocarbons in
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#17327877971544030-507: The use of low-cost electric fuel injection pumps. A very common single-point injection system used in many passenger cars is the Bosch Mono-Jetronic , which German motor journalist Olaf von Fersen considers a "combination of fuel injection and carburettor". The system was called Throttle-body Injection or Digital Fuel Injection by General Motors , Central Fuel Injection by Ford , PGM-CARB by Honda, and EGI by Mazda ). In
4095-449: The years of 1986 to 2021. Japan was first to ban lead in gasoline in 1986, with North and South America following with nearly every country in the two continents banning lead by 1998. Africa was the latest to ban lead in gasoline with most countries banning in 2004 and 2005 and the last, Algeria, which didn’t ban it until 2021. The agencies charged with implementing exhaust emission standards vary from jurisdiction to jurisdiction, even in
4160-478: Was "to follow the operational plans established by previous (GM) Project Centers. Items unique to the "Emissions Control Systems Project Center" (were): The ("Emissions Control Systems Project Center") (had) seven tasks to perform, such that an emission system, which passes all existing Federal Emission and Fuel Economy legislation is put into production. These are to work with the car divisions to: The system implementation (was to) be phased in over three years. In
4225-660: Was allowed in diesel fuel. The amendments also required a procedural change for the creation of gasoline to ensure there are less emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NO X ), particulate matter (PM), and volatile organic compounds (VOCs). Changes made to the CAA also required the use of oxygenated gasoline to reduce CO emissions. Throughout the years, the Environmental Protection Agency (EPA) continued to implement new regulations to reduce harmful emissions for vehicles. Some of
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