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46-410: There are three types of turbine setups used for twin-turbo setups: These can be applied to any of the five types of compressor setups (which theoretically could have 15 different setups): In a parallel configuration, two equally-sized turbochargers each receive half of the exhaust gases . Some designs combine the intake charge from each turbocharger into a single intake manifold , while others use

92-452: 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 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

138-401: 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 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

184-415: A Wankel engine is 3 times smaller than the physical displacement, but this is compensated by the fact that the shaft has 3 times the rotational speed of the rotor. The nominal displacement is the swept volume of a single chamber. Historically, many car model names have included their engine displacement. Examples include the 1923–1930 Cadillac Series 353 (powered by a 353 Cubic inch /5.8-litre engine), and

230-400: 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, 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

276-413: A comparative nominal displacement for variant engine types. In several countries fees and taxes levied on road vehicles by transport authorities are scaled in proportion to engine displacement. In countries where this is practised, vehicle manufacturers often seek to increase power output through higher-revving engines or turbocharging , instead of increasing the displacement. Examples of countries where

322-440: A condition known as diesel engine runaway . Engine displacement Engine displacement is the measure of the cylinder volume swept by all of the pistons of a piston engine , excluding the combustion chambers . It is commonly used as an expression of an engine's size, and by extension as an indicator of the power (through mean effective pressure and rotational speed ) an engine might be capable of producing and

368-425: 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 , 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

414-405: A limiting factor in the peak power produced by the engine. Various technologies, as described in the following sections, are often aimed at combining 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

460-566: A pioneering role with turbocharging engines as witnessed by Sulzer, Saurer and Brown, Boveri & Cie . Automobile manufacturers began research into turbocharged engines during 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

506-465: A separate intake manifold for each turbocharger. Parallel configurations are well suited to V6 and V8 engines since each turbocharger can be assigned to one cylinder bank, reducing the amount of exhaust piping needed. In this case, each turbocharger is fed exhaust gases by a separate exhaust manifold. For four-cylinder engines and straight-six engines , both turbochargers can be mounted to a single exhaust manifold. The aim of using parallel twin-turbos

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552-649: A typical reciprocating piston engine is calculated by multiplying together three values; the distance travelled by the piston (the stroke length ), the circular area of the cylinder, and the number of cylinders in the whole engine. The formula is: Using this formula for non-typical types of engine, such as the Wankel design and the oval-piston type used in Honda NR motorcycles, can sometimes yield misleading results when attempting to compare engines. Manufacturers and regulators may develop and use specialised formulae to determine

598-441: A way to decrease turbo lag without compromising power output at high RPM. The system is arranged so that a small ("primary") turbocharger is active while the engine is operating at low RPM, which reduces the boost threshold (RPM at which effective boost is provided) and turbo lag. As RPM increases, a small amount of exhaust gas is fed to the larger ("secondary") turbocharger, to bring it up to operating speed. Then at high RPM, all of

644-412: 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 is too large, the turbo will fail to create boost at low speeds; if the aspect ratio

690-470: 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,

736-473: Is not a primary design consideration), and where the intake pressure is quite low due to low atmospheric pressure at altitude, requiring a very high pressure ratio. High-performance diesel engines also sometimes use this configuration, since diesel engines do not suffer from pre-ignition issues and can therefore use high boost pressures. http://mkiv.supras.org.nz/articles/twinturbosetups.htm Turbocharger#Compressor In an internal combustion engine ,

782-402: 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 the compressor. The compressor draws in outside air through

828-411: 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 the effective aspect ratio of the turbocharger as operating conditions change. This

874-405: Is to reduce turbo lag by being able to use smaller turbochargers than if a single turbocharger was used for the engine. On engines with multiple cylinder banks (e.g. V engines and flat engines ) use of parallel twin-turbos can also simplify the exhaust system. The 1981–1994 Maserati Biturbo was the first production car to use twin-turbochargers. Sequential turbocharging is a set-up in which

920-490: 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, a lower boost threshold, and greater efficiency at higher engine speeds. The benefit of variable-geometry turbochargers

966-441: 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

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1012-710: The Boeing B-17 Flying Fortress in 1938, which used turbochargers produced by General Electric. Other early turbocharged airplanes included 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

1058-413: 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

1104-577: The 1963–1968 BMW 1800 (a 1.8-litre engine) and Lexus LS 400 with a 3,968 cc engine. This was especially common in US muscle cars , like the Ford Mustang Boss 302 and 429, and later GT 5.0L, The Plymouth Roadrunner 383, and the Chevrolet Chevelle SS 396 and 454. However, trends towards downsizing and hybrid/electric drivetrains since 2010 have resulted in far fewer model names being based on

1150-414: The 1980s, as a way to increase the performance of smaller displacement engines. Like other forced induction devices, 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

1196-527: 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 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

1242-744: 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 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

1288-447: The amount of fuel it should be expected to consume. For this reason displacement is one of the measures often used in advertising, as well as regulating, motor vehicles. It is usually expressed using the metric units of cubic centimetres (cc or cm , equivalent to millilitres ) or litres (l or L), or – particularly in the United States  – cubic inches (CID, cu in, or in ). The overall displacement for

1334-449: 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

1380-403: 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

1426-497: The engine uses one turbocharger for lower engine speeds, and a second or both turbochargers at higher engine speeds. This system is intended to overcome the limitation of large turbochargers providing insufficient boost at low RPM. On the other hand, smaller turbos are effective at low RPM (when there is less kinetic energy present in the exhaust gases) but are unable to provide the quantity of compressed intake gases required at higher RPM. Therefore, sequential turbocharger systems provide

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1472-559: 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

1518-418: 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 a ring of holes or circular grooves allows air to bleed around

1564-430: The exhaust gases are directed to the secondary turbocharger, so that it can provide the boost required by the engine at high RPM. The first production car to use sequential turbocharging was the 1986–1988 Porsche 959 , which used sequential twin-turbos on its flat-six engine. Serial turbocharging is where the turbochargers are connected in series with the output of the first turbocharger then being further compressed by

1610-410: The flow of exhaust gases to mechanical energy of a rotating shaft (which is used to power the compressor section). The turbine housings direct 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

1656-400: 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 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

1702-404: 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

1748-410: 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 the exhaust gases, minimizes parasitic back losses and improves responsiveness at low engine speeds. Another common feature of twin-scroll turbochargers

1794-454: 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

1840-457: The intake pressure). Subsequent turbos take the charge from the previous stage and compress it further (for example to an additional three times intake pressure, for a total boost of nine times atmospheric pressure). A downside of staged turbocharging is that it often leads to large amounts of turbo lag, therefore it is mostly used on piston engine aircraft which usually do not need to rapidly raise and lower engine speed. (and thus where turbo lag

1886-407: The performance requirements. A turbocharger's performance is closely tied to its size, and the relative sizes of the turbine wheel and 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

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1932-548: 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 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

1978-399: 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

2024-404: The road taxes are based upon engine displacement: Wankel engines are able to produce higher power levels for a given displacement. Therefore, they are generally taxed as 1.5 times their stated physical displacement (1.3 litres becomes effectively 2.0, 2.0 becomes effectively 3.0), although actual power outputs can be higher than suggested by this conversion factor. The nominal displacement of

2070-433: The second turbocharger and in some cases powering the larger turbine. A serial turbo can also be of use to a system where the output pressure must be greater than can be provided by a single turbo, commonly called a compound twin-turbo system. In this case, multiple similarly sized turbochargers are used in sequence, but constantly operating. The first turbo boosts provides the initial compression (for example to three times

2116-407: The turbocharger are: The turbine section (also called the "hot side" or "exhaust side" of the turbo) is where 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

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