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Variable Valve Timing
Variable valve timing (VVT) is the process of altering the timing of a Poppet valve, valve lift event in an internal combustion engine, and is often used to improve performance, fuel economy or emissions. It is increasingly being used in combination with variable valve lift systems. There are many ways in which this can be achieved, ranging from mechanical devices to electro-hydraulic and camless systems. Increasingly strict emissions regulations are causing many automotive manufacturers to use VVT systems. Two-stroke cycle, Two-stroke engines use a Two-stroke power valve system, power valve system to get similar results to VVT. Background theory The valves within an internal combustion engine are used to control the flow of the intake and exhaust gases into and out of the combustion chamber. The timing, duration and lift of these valve events has a significant impact on engine performance. Without variable valve timing (variable valve lift), the valve timing is the same for all ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
K20 Head
K, or k, is the eleventh Letter (alphabet), letter of the Latin alphabet, used in the English alphabet, modern English alphabet, the alphabets of other western European languages and others worldwide. Its name in English is English alphabet#Letter names, ''kay'' (pronounced ), plural ''kays''. The letter K usually represents the voiceless velar plosive. History The letter K comes from the Greek letter Κ (kappa), which was taken from the Semitic alphabets, Semitic kaph, the symbol for an open hand. This, in turn, was likely adapted by Semitic people, Semitic tribes who had lived in Egypt from the hieroglyph for hand (hieroglyph), "hand" representing /ḏ/ in the Egyptian word for hand, ⟨wikt:ḏrt, ḏ-r-t⟩ (likely pronounced in Egyptian language, Old Egyptian). The Semites evidently assigned it the sound value instead, because their word for hand started with that sound. K was brought into the Latin alphabet with the name ''ka'' /kaː/ to differentiate it from C, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephenson Valve Gear
The Stephenson valve gear or Stephenson link or shifting link is a simple design of valve gear that was widely used throughout the world for various kinds of steam engines. It is named after Robert Stephenson but was invented by his employees. Historical background During the 1830s, the most popular valve drive for steam locomotives was known as ''gab valve gear, gab motion'' in the History of rail transport in Great Britain 1830–1922, United Kingdom and'' V-hook motion'' in the History of rail transportation in the United States, United States. The gab motion incorporated two sets of eccentrics and rods for each cylinder; one eccentric was set to give forward and the other backwards motion to the engine and one or the other could accordingly engage with a pin driving the distribution valve by means of the gabs: - vee-shaped ends to the eccentric rods supposed to catch the rocker driving the valve rod whatever its position. It was a clumsy mechanism, difficult to operate, and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotational Speed
Rotational frequency, also known as rotational speed or rate of rotation (symbols ''ν'', lowercase Greek nu, and also ''n''), is the frequency of rotation of an object around an axis. Its SI unit is the reciprocal seconds (s−1); other common units of measurement include the hertz (Hz), cycles per second (cps), and revolutions per minute (rpm). Rotational frequency can be obtained dividing ''angular frequency'', ω, by a full turn (2 π radians): ''ν''ω/(2πrad). It can also be formulated as the instantaneous rate of change of the number of rotations, ''N'', with respect to time, ''t'': ''n''d''N''/d''t'' (as per International System of Quantities). (11 pages) Similar to ordinary period (physics), period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lycoming R-7755
The Lycoming XR-7755 was the largest piston aircraft engine ever built in the United States, with 36 cylinders totaling about 7,750 in3 (127 L) of displacement and a power output of 5,000 horsepower (3,700 kilowatts). It was originally intended to be used in the "European bomber" that eventually emerged as the Convair B-36. Only two examples were built before the project was terminated in 1946. Development Lycoming had not been successful in designing a high-power engine. They had started with an attempt to make a hyper engine that led to the 1,200 hp (890 kW) O-1230; by the time the engine was ready, however, new aircraft designs were all calling for more power. They tried again by "twinning" the engine to produce the H block H-2470, which saw some interest in the Vultee XP-54 "Swoose Goose" project. Work on the H-2470 ended when the XP-54 was cancelled. In one final attempt, Lycoming decided to go all out and build what would turn out to be th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Langley Research Center
The Langley Research Center (LaRC or NASA Langley), located in Hampton, Virginia, near the Chesapeake Bay front of Langley Air Force Base, is the oldest of NASA's field centers. LaRC has focused primarily on aeronautical research but has also tested space hardware such as the Apollo Lunar Module. In addition, many of the earliest high-profile space missions were planned and designed on-site. Langley was also considered a potential site for NASA's Manned Spacecraft Center prior to the eventual selection of Houston, Texas. Established in 1917 by the National Advisory Committee for Aeronautics (NACA), the research center devotes two-thirds of its programs to aeronautics and the rest to space. LaRC researchers use more than 40 wind tunnels to study and improve aircraft and spacecraft safety, performance, and efficiency. Between 1958 and 1963, when NASA (the successor agency to NACA) started Project Mercury, LaRC served as the main office of the Space Task Group. In September 201 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radial Engine
The radial engine is a reciprocating engine, reciprocating type internal combustion engine, internal combustion engine configuration in which the cylinder (engine), cylinders "radiate" outward from a central crankcase like the spokes of a wheel. It resembles a stylized Star polygon, star when viewed from the front, and is called a "star engine" in some other languages. The radial configuration was commonly used for aircraft engines before gas turbine engines became predominant. Engine operation Since the axes of the cylinders are coplanar, the connecting rods cannot all be directly attached to the crankshaft unless mechanically complex forked connecting rods are used, none of which have been successful. Instead, the pistons are connected to the crankshaft with a master-and-articulating-rod assembly. One piston, the uppermost one in the animation, has a master rod with a direct attachment to the crankshaft. The remaining pistons pin their connecting rods' attachments to rings ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bristol Jupiter
The Bristol Jupiter is a British nine-cylinder single-row piston radial engine that was built by the Bristol Aeroplane Company. Originally designed late in World War I and known as the Cosmos Jupiter, a lengthy series of upgrades and developments turned it into one of the finest engines of its era. The Jupiter was widely used on many aircraft designs during the 1920s and 1930s. Thousands of Jupiters of all versions were produced, both by Bristol and abroad under licence. A turbo-supercharged version of the Jupiter known as the Orion suffered development problems and only a small number were produced. The "Orion" name was later re-used by Bristol for an unrelated turboprop engine. The Bristol Jupiter was licensed by the Soviet Union as the Shvetsov M-22. Design and development The Jupiter was designed during World War I by Roy Fedden of Brazil Straker and later Cosmos Engineering. The first Jupiter was completed by Brazil Straker in 1918 and featured three carburettors, e ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clerget
Clerget-Blin (full name being ''Société Clerget-Blin et Cie'') was a French precision engineering company formed in 1913 by the engineer and inventor Pierre Clerget and industrialist Eugène Blin. In 1939, the company was absorbed into the ''Groupe d'étude des moteurs à huile lourde'' (GEHL; "Diesel Engine Study Group"), which was further merged into SNECMA in 1947. Products The Clerget-Blin company mainly produced aircraft engines. Their successful rotary engine designs were also built in Britain by companies such as Gwynnes Limited, Ruston Proctor, and Gordon Watney, to increase production during World War I.Lumsden 2003, p.133. See also *List of aircraft engine manufacturers This is a list of aircraft engine manufacturers both past and present. 0–9 * 2si – US * 3w (aero-engine manufacturer), 3WMiguel Vidal, Ricardo. ''El Motor de Aviación de la A a la Z. ''Aeroteca, 2012. A * Alliott Verdon Roe, A.V. Roe ... Notes Bibliography * Gunston, Bill. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Léon Serpollet
Léon Serpollet (4 October 1858 – 1 February 1907) was a French engineer and developer of flash steam boilers and steam automobiles. Léon Serpollet was born in Culoz, in the Ain department of France in 1859, son of the carpenter Auguste Serpollet. He went into the family business with his brother Henri (1848–1915) producing circular saws and wood working machines. It was when seeking to power their workshops that Henri came up with the idea of flash steam generation, with a patent applied for on 25 October 1879. Leon went to Paris to study engineering at the Conservatoire national des arts et métiers, and at the same time he continued to develop the flash steam concept with his brother by post. In 1886 the two brothers arrived at their best design of flash steam boiler, and then shortly afterwards they went into business building flash steam boilers, initially small scale to power lighting systems and pumps, but soon to power tricycles and steam boats, and eventually ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Poppet Valve
A poppet valve (also sometimes called mushroom valve) is a valve typically used to control the timing and quantity of petrol (gas) or vapour flow into or out of an engine, but with many other applications. It consists of a hole or open-ended chamber, usually round or oval in cross-section, and a plug, usually a disk shape on the end of a shaft known as a valve stem. The working end of this plug, the valve face, is typically ground at a 45° bevel to seal against a corresponding valve seat ground into the rim of the chamber being sealed. The shaft travels through a valve guide to maintain its alignment. A pressure differential on either side of the valve can assist or impair its performance. In exhaust applications higher pressure against the valve helps to seal it, and in intake applications lower pressure helps open it. Etymology The word poppet shares etymology with "puppet": it is from the Middle English ''popet'' ("youth" or "doll"), from Middle French ''poupette'', whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trip Valve
Trip valve mechanisms are a class of steam engine valve gear developed to improve efficiency. The trip mechanism allows the inlet valve to be closed rapidly, giving a short, sharp cut-off. The valve itself can be a drop valve or a Corliss valve. Trip valve gear was applied to larger stationary engines. It was not used in transport applications,An exception was the very early London Steam Carriage (1803) which had a form of trip gear. as it was not suitable for high speed. The trip point of the valve mechanism, and therefore the cut-off, would be adjusted either manually or automatically by the governor. The valve is opened by the mechanical valve gear mechanism, and when the trip gear trigger releases the mechanism the valve is snapped closed, usually by a spring acting against a dashpot A dashpot, also known as a damper, is a mechanical device that resists motion via viscous damping. The resulting force is proportional to the velocity, but acts in the opposite direction, sl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
