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65-405: The GP20 was the second EMD production locomotive to be built with an EMD turbocharged diesel engine, sixteen months after the six-axle ( C-C ) model SD24 . Power output of the turbocharged SD24 was 33 percent higher than the 1,800 hp (1,340 kW) of the concurrent Roots blower -equipped SD18s with the same engine displacement , 400 hp (298 kW) per axle, but the power output of

130-406: A compressor in the turbocharger pressurises the intake air before it enters the inlet manifold . In the case of a turbocharger, the compressor is powered by the kinetic energy of the engine's exhaust gases, which is extracted by the turbocharger's turbine . The main components of the turbocharger are: The turbine section (also called the "hot side" or "exhaust side" of the turbo) is where

195-739: A National Aerodynamical Laboratory Commission chaired by Robert S. Woodward , president of the Carnegie Institution of Washington . Legislation was introduced in both houses of Congress early in January 1913 to approve the commission, but when it came to a vote, the legislation was defeated. Charles D. Walcott , secretary of the Smithsonian Institution from 1907 to 1927, took up the effort, and in January 1915, Senator Benjamin R. Tillman , and Representative Ernest W. Roberts introduced identical resolutions recommending

260-406: A Swiss engineer working at Sulzer is often considered the birth of the turbocharger. This patent was for a compound radial engine with an exhaust-driven axial flow turbine and compressor mounted on a common shaft. The first prototype was finished in 1915 with the aim of overcoming the power loss experienced by aircraft engines due to the decreased density of air at high altitudes. However,

325-473: A condition known as diesel engine runaway . National Advisory Committee for Aeronautics The National Advisory Committee for Aeronautics ( NACA ) was a United States federal agency that was founded on March 3, 1915, to undertake, promote, and institutionalize aeronautical research. On October 1, 1958, the agency was dissolved and its assets and personnel were transferred to the newly created National Aeronautics and Space Administration (NASA). NACA

390-437: A contract basis. In 1922, NACA had 100 employees. By 1938, it had 426. In addition to formal assignments, staff were encouraged to pursue unauthorized "bootleg" research, provided that it was not too exotic. The result was a long string of fundamental breakthroughs, including " thin airfoil theory " (1920s), " NACA engine cowl " (1930s), the " NACA airfoil " series (1940s), and the " area rule " for supersonic aircraft (1950s). On

455-464: A feasible front line fighter by European standards, and so North American began development of a new aircraft. The British government chose a NACA-developed airfoil for the fighter, which enabled it to perform dramatically better than previous models. This aircraft became known as the P-51 Mustang . After early experiments by Opel RAK with rocket propulsion leading to the first public flight of

520-460: A lower boost threshold, and greater efficiency at higher engine speeds. The benefit of variable-geometry turbochargers is that the optimum aspect ratio at low engine speeds is very different from that at high engine speeds. An electrically-assisted turbocharger combines a traditional exhaust-powered turbine with an electric motor, in order to reduce turbo lag. This differs from an electric supercharger , which solely uses an electric motor to power

585-433: A nation as well as military necessity that this challenge ( Sputnik ) be met by an energetic program of research and development for the conquest of space. ... It is accordingly proposed that the scientific research be the responsibility of a national civilian agency working in close cooperation with the applied research and development groups required for weapon systems development by the military. The pattern to be followed

650-512: A ring of holes or circular grooves allows air to bleed around the compressor blades. Ported shroud designs can have greater resistance to compressor surge and can improve the efficiency of the compressor wheel. The center hub rotating assembly (CHRA) houses the shaft that connects the turbine to the compressor. A lighter shaft can help reduce turbo lag. The CHRA also contains a bearing to allow this shaft to rotate at high speeds with minimal friction. Some CHRAs are water-cooled and have pipes for

715-629: A rocket plane, the Opel RAK.1 , in 1929 and eventual military programs at Heinkel and Messerschmitt by Nazi Germany in the 1930s and 1940s, the US entered the race to supersonic planes and spaceflight in the 1940s. Although the Bell X-1 was commissioned by the Air Force and flown by Air Force test pilot Chuck Yeager , when it exceeded Mach 1 NACA was officially in charge of the testing and development of

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780-404: A series were offered with turbocharging (e.g., the 38 models were Roots-blown). Turbocharger#Marine and land-based diesel turbochargers In an internal combustion engine , a turbocharger (also known as a turbo or a turbosupercharger ) is a forced induction device that is powered by the flow of exhaust gases. It uses this energy to compress the intake air, forcing more air into

845-445: A true turbocharger. It is possible for the turbo-compressor to revert to compressor mode momentarily during commands for large increases in engine power. Turbocharging provides higher horsepower and good running characteristics at all altitudes. Turbocharging also improves fuel consumption and reduces emissions. Previous Union Pacific experiments with turbocharging had utilized multiple Elliot or Garrett AiResearch turbochargers feeding

910-482: Is an initialism, i.e., pronounced as individual letters, rather than as a whole word (as was NASA during the early years after being established). Among other advancements, NACA research and development produced the NACA duct , a type of air intake used in modern automotive applications, the NACA cowling , and several series of NACA airfoils , which are still used in aircraft manufacturing. During World War II, NACA

975-474: Is increasing. The companies which manufacture the most turbochargers in Europe and the U.S. are Garrett Motion (formerly Honeywell), BorgWarner and Mitsubishi Turbocharger . Turbocharger failures and resultant high exhaust temperatures are among the causes of car fires. Failure of the seals will cause oil to leak into the cylinders causing blue-gray smoke. In diesel engines, this can cause an overspeed,

1040-552: Is now used in designing all transonic and supersonic aircraft. NACA experience provided a model for World War II research, the postwar government laboratories, and NACA's successor, the National Aeronautics and Space Administration (NASA). NACA also participated in development of the first aircraft to fly to the "edge of space", North American's X-15 . NACA airfoils are still used on modern aircraft. On November 21, 1957, Hugh Dryden , NACA's director, established

1105-576: Is that already developed by the NACA and the military services. ... The NACA is capable, by rapid extension and expansion of its effort, of providing leadership in space technology. On March 5, 1958, James Killian , who chaired the President's Science Advisory Committee , wrote a memorandum to the President Dwight D. Eisenhower . Titled, "Organization for Civil Space Programs", it encouraged

1170-453: Is too large, the turbo will fail to create boost at low speeds; if the aspect ratio is too small, the turbo will choke the engine at high speeds, leading to high exhaust manifold pressures, high pumping losses, and ultimately lower power output. By altering the geometry of the turbine housing as the engine accelerates, the turbo's aspect ratio can be maintained at its optimum. Because of this, variable-geometry turbochargers often have reduced lag,

1235-441: Is unable to produce significant boost. At low rpm, the exhaust gas flow rate is unable to spin the turbine sufficiently. The boost threshold causes delays in the power delivery at low rpm (since the unboosted engine must accelerate the vehicle to increase the rpm above the boost threshold), while turbo lag causes delay in the power delivery at higher rpm. Some engines use multiple turbochargers, usually to reduce turbo lag, increase

1300-549: The Boeing B-17 Flying Fortress to maintain power at high altitude, a team of engineers from NACA solved the problems and created the standards and testing methods used to produce effective superchargers in the future. This enabled the B-17 to be used as a key aircraft in the war effort. The designs and information gained from NACA research on the B-17 were used in nearly every major U.S. military powerplant of

1365-701: The Consolidated B-24 Liberator , Lockheed P-38 Lightning , Republic P-47 Thunderbolt and experimental variants of the Focke-Wulf Fw 190 . The first practical application for trucks was realized by Swiss truck manufacturing company Saurer in the 1930s. BXD and BZD engines were manufactured with optional turbocharging from 1931 onwards. The Swiss industry played a pioneering role with turbocharging engines as witnessed by Sulzer, Saurer and Brown, Boveri & Cie . Automobile manufacturers began research into turbocharged engines during

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1430-573: The Convair F-102 project and the F11F Tiger . The F-102 was meant to be a supersonic interceptor, but it was unable to exceed the speed of sound, despite the best effort of Convair engineers. The F-102 had actually already begun production when this was discovered, so NACA engineers were sent to quickly solve the problem at hand. The production line had to be modified to allow the modification of F-102s already in production to allow them to use

1495-469: The Preussen and Hansestadt Danzig . The design was licensed to several manufacturers and turbochargers began to be used in marine, railcar and large stationary applications. Turbochargers were used on several aircraft engines during World War II, beginning with the Boeing B-17 Flying Fortress in 1938, which used turbochargers produced by General Electric. Other early turbocharged airplanes included

1560-564: The US Army's Ballistic Missile Agency would have a Jupiter C rocket ready to launch a satellite in 1956, only to have it delayed, and the Soviets would launch Sputnik 1 in October 1957. On January 14, 1958, Dryden published "A National Research Program for Space Technology", which stated: It is of great urgency and importance to our country both from consideration of our prestige as

1625-413: The crankshaft ) whereas a turbocharger is powered by the kinetic energy of the engine's exhaust gas . A turbocharger does not place a direct mechanical load on the engine, although turbochargers place exhaust back pressure on engines, increasing pumping losses. Supercharged engines are common in applications where throttle response is a key concern, and supercharged engines are less likely to heat soak

1690-511: The 1950s, however the problems of "turbo lag" and the bulky size of the turbocharger were not able to be solved at the time. The first turbocharged cars were the short-lived Chevrolet Corvair Monza and the Oldsmobile Jetfire , both introduced in 1962. Greater adoption of turbocharging in passenger cars began in the 1980s, as a way to increase the performance of smaller displacement engines. Like other forced induction devices,

1755-795: The German Aerodynamic Laboratory of the University of Göttingen , and the Russian Aerodynamic Institute of Koutchino (replaced in 1918 with the Central Aerohydrodynamic Institute (TsAGI) , which is still in existence). The most influential agency upon which the NACA was based was the British Advisory Committee for Aeronautics . In December 1912, President William Howard Taft had appointed

1820-744: The P-38 Lightning. The X-1 program was first envisioned in 1944 when a former NACA engineer working for Bell Aircraft approached the Army for funding of a supersonic test aircraft. Neither the Army nor Bell had any experience in this area, so the majority of research came from the NACA Compressibility Research Division, which had been operating for more than a year by the time Bell began conceptual designs. The Compressibility Research Division also had years of additional research and data to pull from, as its head engineer

1885-472: The President to sanction the creation of NASA. He wrote that a civil space program should be based on a "strengthened and redesignated" NACA, indicating that NACA was a "going Federal research agency" with 7,500 employees and $ 300 million worth of facilities, which could expand its research program "with a minimum of delay". As of their meeting on May 26, 1958, committee members, starting clockwise from

1950-575: The Second World War. Nearly every aircraft used some form of forced induction that relied on information developed by NACA. Because of this, U.S.-produced aircraft had a significant power advantage above 15,000 feet, which was never fully countered by Axis forces. After the war had begun, the British government sent a request to North American Aviation for a new fighter. The offered P-40 Tomahawk fighters were considered too outdated to be

2015-658: The Special Committee on Space Technology. The committee, also called the Stever Committee after its chairman, Guyford Stever , was a special steering committee that was formed with the mandate to coordinate various branches of the federal government, private companies as well as universities within the United States with NACA's objectives and also harness their expertise in order to develop a space program. Wernher von Braun , technical director at

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2080-406: The aircraft. NACA ran the experiments and data collection, and the bulk of the research used to develop the aircraft came from NACA engineer John Stack , the head of NACA's compressibility division. Compressibility is a major issue as aircraft approach Mach 1, and research into solving the problem drew heavily on information collected during previous NACA wind tunnel testing to assist Lockheed with

2145-617: The area rule. (Aircraft so altered were known as "area ruled" aircraft.) The design changes allowed the aircraft to exceed Mach 1, but only by a small margin, as the rest of the Convair design was not optimized for this. As the F-11F was the first design to incorporate this during initial design, it was able to break the sound barrier without having to use afterburner. Because the area rule was initially classified, it took several years for Whitcomb to be recognized for his accomplishment. In 1955 he

2210-406: The benefits of both small turbines and large turbines. Large diesel engines often use a single-stage axial inflow turbine instead of a radial turbine. A twin-scroll turbocharger uses two separate exhaust gas inlets, to make use of the pulses in the flow of the exhaust gasses from each cylinder. In a standard (single-scroll) turbocharger, the exhaust gas from all cylinders is combined and enters

2275-421: The compressor wheel. Large turbines typically require higher exhaust gas flow rates, therefore increasing turbo lag and increasing the boost threshold. Small turbines can produce boost quickly and at lower flow rates, since it has lower rotational inertia, but can be a limiting factor in the peak power produced by the engine. Various technologies, as described in the following sections, are often aimed at combining

2340-419: The compressor. The compressor draws in outside air through the engine's intake system, pressurises it, then feeds it into the combustion chambers (via the inlet manifold ). The compressor section of the turbocharger consists of an impeller, a diffuser, and a volute housing. The operating characteristics of a compressor are described by the compressor map . Some turbochargers use a "ported shroud", whereby

2405-510: The creation of an advisory committee as outlined by Walcott. The purpose of the committee was "to supervise and direct the scientific study of the problems of flight with a view to their practical solution, and to determine the problems which should be experimentally attacked and to discuss their solution and their application to practical questions". Assistant Secretary of the Navy Franklin D. Roosevelt wrote that he "heartily [endorsed]

2470-399: The early 1920s, it had adopted a new and more ambitious mission: to promote military and civilian aviation through applied research that looked beyond current needs. NACA researchers pursued this mission through the agency's impressive collection of in-house wind tunnels, engine test stands, and flight test facilities. Commercial and military clients were also permitted to use NACA facilities on

2535-413: The effective aspect ratio of the turbocharger as operating conditions change. This is done with the use of adjustable vanes located inside the turbine housing between the inlet and turbine, which affect flow of gases towards the turbine. Some variable-geometry turbochargers use a rotary electric actuator to open and close the vanes, while others use a pneumatic actuator . If the turbine's aspect ratio

2600-421: The engine in order to produce more power for a given displacement . The current categorisation is that a turbocharger is powered by the kinetic energy of the exhaust gases, whereas a supercharger is mechanically powered (usually by a belt from the engine's crankshaft). However, up until the mid-20th century, a turbocharger was called a "turbosupercharger" and was considered a type of supercharger. Prior to

2665-403: The engine rpm is within the turbocharger's operating range – that occurs between pressing the throttle and the turbocharger spooling up to provide boost pressure. This delay is due to the increasing exhaust gas flow (after the throttle is suddenly opened) taking time to spin up the turbine to speeds where boost is produced. The effect of turbo lag is reduced throttle response , in

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2730-559: The engine's coolant to flow through. One reason for water cooling is to protect the turbocharger's lubricating oil from overheating. The simplest type of turbocharger is the free floating turbocharger. This system would be able to achieve maximum boost at maximum engine revs and full throttle, however additional components are needed to produce an engine that is driveable in a range of load and rpm conditions. Additional components that are commonly used in conjunction with turbochargers are: Turbo lag refers to delay – when

2795-482: The exhaust gases, minimizes parasitic back losses and improves responsiveness at low engine speeds. Another common feature of twin-scroll turbochargers is that the two nozzles are different sizes: the smaller nozzle is installed at a steeper angle and is used for low-rpm response, while the larger nozzle is less angled and optimised for times when high outputs are required. Variable-geometry turbochargers (also known as variable-nozzle turbochargers ) are used to alter

2860-404: The form of a delay in the power delivery. Superchargers do not suffer from turbo lag because the compressor mechanism is driven directly by the engine. Methods to reduce turbo lag include: A similar phenomenon that is often mistaken for turbo lag is the boost threshold . This is where the engine speed (rpm) is currently below the operating range of the turbocharger system, therefore the engine

2925-405: The gas flow through the turbine section, and the turbine itself can spin at speeds of up to 250,000 rpm. Some turbocharger designs are available with multiple turbine housing options, allowing a housing to be selected to best suit the engine's characteristics and the performance requirements. A turbocharger's performance is closely tied to its size, and the relative sizes of the turbine wheel and

2990-454: The intake air. A combination of an exhaust-driven turbocharger and an engine-driven supercharger can mitigate the weaknesses of both. This technique is called twincharging . Turbochargers have been used in the following applications: In 2017, 27% of vehicles sold in the US were turbocharged. In Europe 67% of all vehicles were turbocharged in 2014. Historically, more than 90% of turbochargers were diesel, however, adoption in petrol engines

3055-435: The invention of the turbocharger, forced induction was only possible using mechanically-powered superchargers . Use of superchargers began in 1878, when several supercharged two-stroke gas engines were built using a design by Scottish engineer Dugald Clerk . Then in 1885, Gottlieb Daimler patented the technique of using a gear-driven pump to force air into an internal combustion engine. The 1905 patent by Alfred Büchi ,

3120-463: The matter and overruled NACA objections to higher air speeds. NACA built a handful of new high-speed wind tunnels, and Mach 0.75 (570 mph (495 kn; 917 km/h)) was reached at Moffett's 16-foot (4.9 m) wind tunnel late in 1942. NACA's first wind tunnel was formally dedicated at Langley Memorial Aeronautical Laboratory on June 11, 1920. It was the first of many now-famous NACA and NASA wind tunnels. Although this specific wind tunnel

3185-710: The other hand, NACA's 1941 refusal to increase airspeed in their wind tunnels set Lockheed back a year in their quest to solve the problem of compressibility encountered in high speed dives made by the Lockheed P-38 Lightning . The full-size 30-by-60-foot (9.1 m × 18.3 m) Langley wind tunnel operated at no more than 100 mph (87 kn; 160 km/h) and the then-recent 7-by-10-foot (2.1 m × 3.0 m) tunnels at Moffett could only reach 250 mph (220 kn; 400 km/h). These were speeds Lockheed engineers considered useless for their purposes. General Henry H. Arnold took up

3250-567: The power produced at sea level) at an altitude of up to 4,250 m (13,944 ft) above sea level. The testing was conducted at Pikes Peak in the United States using the Liberty L-12 aircraft engine. The first commercial application of a turbocharger was in June 1924 when the first heavy duty turbocharger, model VT402, was delivered from the Baden works of Brown, Boveri & Cie , under

3315-599: The principle" on which the legislation was based. Walcott suggested the tactic of adding the resolution to the Naval Appropriations Bill. According to one source, "The enabling legislation for the NACA slipped through almost unnoticed as a rider attached to the Naval Appropriation Bill, on March 3, 1915." The committee of 12 people, all unpaid, were allocated a budget of $ 5,000 per year. President Woodrow Wilson signed it into law

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3380-595: The prototype was not reliable and did not reach production. Another early patent for turbochargers was applied for in 1916 by French steam turbine inventor Auguste Rateau , for their intended use on the Renault engines used by French fighter planes. Separately, testing in 1917 by the National Advisory Committee for Aeronautics (NACA) and Sanford Alexander Moss showed that a turbocharger could enable an engine to avoid any power loss (compared with

3445-399: The range of rpm where boost is produced, or simplify the layout of the intake/exhaust system. The most common arrangement is twin turbochargers, however triple-turbo or quad-turbo arrangements have been occasionally used in production cars. The key difference between a turbocharger and a supercharger is that a supercharger is mechanically driven by the engine (often through a belt connected to

3510-436: The rotational force is produced, in order to power the compressor (via a rotating shaft through the center of a turbo). After the exhaust has spun the turbine it continues into the exhaust piping and out of the vehicle. The turbine uses a series of blades to convert kinetic energy from the flow of exhaust gases to mechanical energy of a rotating shaft (which is used to power the compressor section). The turbine housings direct

3575-602: The same day, thus formally creating the Advisory Committee for Aeronautics, as it was called in the legislation, on the last day of the 63rd Congress . The act of Congress creating NACA, approved March 3, 1915, reads, "...It shall be the duty of the advisory committee for aeronautics to supervise and direct the scientific study of the problems of flight with a view to their practical solution. ... " On January 29, 1920, President Wilson appointed pioneering flier and aviation engineer Orville Wright to NACA's board. By

3640-606: The sound barrier. NACA was established on March 13, 1915, by the federal government through enabling legislation as an emergency measure during World War I to promote industry, academic, and government coordination on war-related projects. It was modeled on similar national agencies found in Europe: the French L'Etablissement Central de l'Aérostation Militaire in Meudon (now Office National d'Etudes et de Recherches Aerospatiales ),

3705-525: The supervision of Alfred Büchi, to SLM, Swiss Locomotive and Machine Works in Winterthur. This was followed very closely in 1925, when Alfred Büchi successfully installed turbochargers on ten-cylinder diesel engines, increasing the power output from 1,300 to 1,860 kilowatts (1,750 to 2,500 hp). This engine was used by the German Ministry of Transport for two large passenger ships called

3770-479: The turbocharged GP20 was only 11 percent higher than the 1,800 hp (1,340 kW) of the concurrent Roots blower-equipped GP18s with the same engine displacement 500 hp (373 kW) per axle, due to the limitations of the traction motors then available. Nevertheless, the turbocharged GP20 provided full rated power at all altitudes, which the Roots-blown GP18 could not provide. The turbocharger

3835-500: The turbocharger via a single intake, which causes the gas pulses from each cylinder to interfere with each other. For a twin-scroll turbocharger, the cylinders are split into two groups in order to maximize the pulses. The exhaust manifold keeps the gases from these two groups of cylinders separated, then they travel through two separate spiral chambers ("scrolls") before entering the turbine housing via two separate nozzles. The scavenging effect of these gas pulses recovers more energy from

3900-527: The usual pair of Roots blowers. EMD's mechanically assisted turbocharger eliminated the need for the pair of Roots blowers and also integrated the turbocharging function from two (Elliot) or four (AiResearch) smaller add-on turbochargers into one much larger, turbo-compressor (turbocharger) with intercooling. The introduction of the EMD-type turbocharger was successful and all subsequent GP series were offered with this turbocharger, although not all models within

3965-697: Was awarded the Collier Trophy for his work on both the Tiger and the F-102. The most important design resulting from the area rule was the B-58 Hustler , which was already in development at the time. It was redesigned to take the area rule into effect, allowing greatly improved performance. This was the first US supersonic bomber, and was capable of Mach 2 at a time when Soviet fighters had only just attained that speed months earlier. The area rule concept

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4030-480: Was described as "The Force Behind Our Air Supremacy" due to its key role in producing working superchargers for high altitude bombers, and for producing the laminar wing profiles for the North American P-51 Mustang . NACA also helped in developing the area rule that is used on all modern supersonic aircraft , and conducted the key compressibility research that enabled the Bell X-1 to break

4095-430: Was not unique or advanced, it enabled NACA engineers and scientists to develop and test new and advanced concepts in aerodynamics and to improve future wind tunnel design. In the years immediately preceding World War II, NACA was involved in the development of several designs that served key roles in the war effort. When engineers at a major engine manufacturer were having issues producing superchargers that would allow

4160-514: Was previously head of the high speed wind tunnel division, which itself had nearly a decade of high speed test data by that time. Due to the importance of NACA involvement, Stack was personally awarded the Collier Trophy along with the owner of Bell Aircraft and test pilot Chuck Yeager. In 1951, NACA Engineer Richard Whitcomb determined the area rule that explained transonic flow over an aircraft. The first uses of this theory were on

4225-426: Was the then-new EMD mechanically assisted turbo-compressor. During engine startup, and at lower power levels, during which there is not sufficient exhaust heat energy to drive the turbine fast enough for the compressor to supply the air necessary for combustion, the engine drives the compressor through a gear train and a freewheel . At higher power levels, the freewheel is disengaged, and the turbo-compressor operates as

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