Aluminium or aluminum is a chemical element with symbol Al and atomic number 13. It is a silvery-white, soft and ductile metal in the boron group. By mass, aluminium makes up about 8% of the Earth's crust; the chief ore of aluminium is bauxite. Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is found combined in over 270 different minerals. Aluminium is remarkable for its low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the aerospace industry and important in transportation and building industries, such as building facades and window frames; the oxides and sulfates are the most useful compounds of aluminium. Despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals; because of these salts' abundance, the potential for a biological role for them is of continuing interest, studies continue.
Of aluminium isotopes, only 27Al is stable. This is consistent with aluminium having an odd atomic number, it is the only aluminium isotope that has existed on Earth in its current form since the creation of the planet. Nearly all the element on Earth is present as this isotope, which makes aluminium a mononuclidic element and means that its standard atomic weight equates to that of the isotope; the standard atomic weight of aluminium is low in comparison with many other metals, which has consequences for the element's properties. All other isotopes of aluminium are radioactive; the most stable of these is 26Al and therefore could not have survived since the formation of the planet. However, 26Al is produced from argon in the atmosphere by spallation caused by cosmic ray protons; the ratio of 26Al to 10Be has been used for radiodating of geological processes over 105 to 106 year time scales, in particular transport, sediment storage, burial times, erosion. Most meteorite scientists believe that the energy released by the decay of 26Al was responsible for the melting and differentiation of some asteroids after their formation 4.55 billion years ago.
The remaining isotopes of aluminium, with mass numbers ranging from 21 to 43, all have half-lives well under an hour. Three metastable states are known, all with half-lives under a minute. An aluminium atom has 13 electrons, arranged in an electron configuration of 3s23p1, with three electrons beyond a stable noble gas configuration. Accordingly, the combined first three ionization energies of aluminium are far lower than the fourth ionization energy alone. Aluminium can easily surrender its three outermost electrons in many chemical reactions; the electronegativity of aluminium is 1.61. A free aluminium atom has a radius of 143 pm. With the three outermost electrons removed, the radius shrinks to 39 pm for a 4-coordinated atom or 53.5 pm for a 6-coordinated atom. At standard temperature and pressure, aluminium atoms form a face-centered cubic crystal system bound by metallic bonding provided by atoms' outermost electrons; this crystal system is shared by some other metals, such as copper. Aluminium metal, when in quantity, is shiny and resembles silver because it preferentially absorbs far ultraviolet radiation while reflecting all visible light so it does not impart any color to reflected light, unlike the reflectance spectra of copper and gold.
Another important characteristic of aluminium is its low density, 2.70 g/cm3. Aluminium is a soft, lightweight and malleable with appearance ranging from silvery to dull gray, depending on the surface roughness, it is nonmagnetic and does not ignite. A fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation; the yield strength of pure aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has stiffness of steel, it is machined, cast and extruded. Aluminium atoms are arranged in a face-centered cubic structure. Aluminium has a stacking-fault energy of 200 mJ/m2. Aluminium is a good thermal and electrical conductor, having 59% the conductivity of copper, both thermal and electrical, while having only 30% of copper's density. Aluminium is capable of superconductivity, with a superconducting critical temperature of 1.2 kelvin and a critical magnetic field of about 100 gauss.
Aluminium is the most common material for the fabrication of superconducting qubits. Aluminium's corrosion resistance can be excellent due to a thin surface layer of aluminium oxide that forms when the bare metal is exposed to air preventing further oxidation, in a process termed passivation; the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts in the presence of dissimilar metals. In acidic solutions, aluminium reacts with water to form hydrogen, in alkaline ones to form aluminates—protective passivation under these conditions is negligible; because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium. However, because
In an internal combustion engine, the cylinder head sits above the cylinders on top of the cylinder block. It closes in the top of the cylinder; this joint is sealed by a head gasket. In most engines, the head provides space for the passages that feed air and fuel to the cylinder, that allow the exhaust to escape; the head can be a place to mount the valves, spark plugs, fuel injectors. In a flathead or sidevalve engine, the mechanical parts of the valve train are all contained within the block, a'poultice head' may be used, a simple metal plate bolted to the top of the block. Keeping all moving parts within the block has an advantage for physically large engines in that the camshaft drive gear is small and so suffers less from the effects of thermal expansion in the cylinder block. With a chain drive to an overhead camshaft, the extra length of chain needed for an overhead cam design could give trouble from wear and slop in the chain without frequent maintenance. Early sidevalve engines were in use at a time of simple fuel chemistry, low octane ratings and so required low compression ratios.
This made their combustion chamber design less critical and there was less need to design their ports and airflow carefully. One difficulty experienced at this time was that the low compression ratio implied a low expansion ratio during the power stroke. Exhaust gases were thus still hot, hotter than a contemporary engine, this led to frequent trouble with burnt exhaust valves. A major improvement to the sidevalve engine was the advent of Ricardo's turbulent head design; this reduced the space within the combustion chamber and the ports, but by careful thought about the airflow paths within them it allowed a more efficient flow in and out of the chamber. Most it used turbulence within the chamber to mix the fuel and air mixture. This, of itself, allowed the use of higher compression ratios and more efficient engine operation; the limit on sidevalve performance is not the gas flow through the valves, but rather the shape of the combustion chamber. With high speed engines and high compression, the limiting difficulty becomes that of achieving complete and efficient combustion, whilst avoiding the problems of unwanted pre-detonation.
The shape of a sidevalve combustion chamber, being wider than the cylinder to reach the valve ports, conflicts with achieving both an ideal shape for combustion and the small volume needed for high compression. Modern, efficient engines thus tend towards the pent roof or hemi designs, where the valves are brought close in to the centre of the space. Where fuel quality is low and octane rating is poor, compression ratios will be restricted. In these cases, the sidevalve engine still has much to offer. In the case of the developed IOE engine for a market with poor fuels, engines such as Rolls-Royce B series or the Land-Rover use a complicated arrangement of inclined valves, a cylinder head line at an angle to the bore and corresponding angled pistons to provide a compact combustion chamber approaching the near-hemispherical ideal; such engines remained in production into the 1990s, only being replaced when the fuels available'in the field' became more to be diesel than petrol. Internally, the cylinder head has passages called ports or tracts for the fuel/air mixture to travel to the inlet valves from the intake manifold, for exhaust gases to travel from the exhaust valves to the exhaust manifold.
In a water-cooled engine, the cylinder head contains integral ducts and passages for the engines' coolant—usually a mixture of water and antifreeze—to facilitate the transfer of excess heat away from the head, therefore the engine in general. In the overhead valve design, the cylinder head contains the poppet valves and the spark plugs, along with tracts or'ports' for the inlet and exhaust gases; the operation of the valves is initiated by the engine's camshaft, sited within the cylinder block, its moment of operation is transmitted to the valves' pushrods, rocker arms mounted on a rocker shaft—the rocker arms and shaft being located within the cylinder head. In the overhead camshaft design, the cylinder head contains the valves, spark plugs and inlet/exhaust tracts just like the OHV engine, but the camshaft is now contained within the cylinder head; the camshaft may be seated centrally between each offset row of inlet and exhaust valves, still utilizing rocker arms, or the camshaft may be seated directly above the valves eliminating the rocker arms and utilizing'bucket' tappets.
The number of cylinder heads in an engine is a function of the engine configuration. All inline engines today use a single cylinder head that serves all the cylinders. A V engine has two cylinder heads, one for each cylinder bank of the'V'. For a few compact'narrow angle' V engines, such as the Volkswagen VR6, the angle between the cylinder banks is so narrow that it uses a single head spanning the two banks. A flat engine has two heads. Most radial engines have one head for each cylinder, although this is of the monobloc form wherein the head is made as an integral part of the cylinder; this is common for motorcycles, such head/cylinder components are referred-to as barrels. Some engines medium- and large-capacity diesel engines built for industrial, power generation, heavy traction purposes have individual cylinder heads for each cylinder; this reduces repair costs as a single failed head on a
A crankshaft—related to crank—is a mechanical part able to perform a conversion between reciprocating motion and rotational motion. In a reciprocating engine, it translates reciprocating motion of the piston into rotational motion. In order to do the conversion between two motions, the crankshaft has "crank throws" or "crankpins", additional bearing surfaces whose axis is offset from that of the crank, to which the "big ends" of the connecting rods from each cylinder attach, it is connected to a flywheel to reduce the pulsation characteristic of the four-stroke cycle, sometimes a torsional or vibrational damper at the opposite end, to reduce the torsional vibrations caused along the length of the crankshaft by the cylinders farthest from the output end acting on the torsional elasticity of the metal. The earliest hand-operated cranks appeared in China during the Han Dynasty, they were used for silk-reeling, hemp-spinning, for the agricultural winnowing fan, in the water-powered flour-sifter, for hydraulic-powered metallurgic bellows, in the well windlass.
The rotary winnowing fan increased the efficiency of separating grain from husks and stalks. However, the potential of the crank of converting circular motion into reciprocal motion never seems to have been realized in China, the crank was absent from such machines until the turn of the 20th century. Al-Jazari described a crank and connecting rod system in a rotating machine in two of his water-raising machines, his twin-cylinder pump incorporated a crankshaft, including both the crank and shaft mechanisms. The 15th century saw the introduction of cranked rack-and-pinion devices, called cranequins, which were fitted to the crossbow's stock as a means of exerting more force while spanning the missile weapon. In the textile industry, cranked reels for winding skeins of yarn were introduced. Around 1480, the early medieval rotary grindstone was improved with a crank mechanism. Cranks mounted on push-carts first appear in a German engraving of 1589. Crankshafts were described by Leonardo da Vinci and a Dutch farmer and windmill owner by the name Cornelis Corneliszoon van Uitgeest in 1592.
His wind-powered sawmill used a crankshaft to convert a windmill's circular motion into a back-and-forward motion powering the saw. Corneliszoon was granted a patent for his crankshaft in 1597. From the 16th century onwards, evidence of cranks and connecting rods integrated into machine design becomes abundant in the technological treatises of the period: Agostino Ramelli's The Diverse and Artifactitious Machines of 1588 depicts eighteen examples, a number that rises in the Theatrum Machinarum Novum by Georg Andreas Böckler to 45 different machines. Cranks were common on some machines in the early 20th century. Reciprocating piston engines use cranks to convert the linear piston motion into rotational motion. Internal combustion engines of early 20th century automobiles were started with hand cranks, before electric starters came into general use; the 1918 Reo owner's manual describes how to hand crank the automobile: First: Make sure the gear shifting lever is in neutral position. Second: The clutch pedal is unlatched and the clutch engaged.
The brake pedal is pushed forward as far as possible setting brakes on the rear wheel. Third: See that spark control lever, the short lever located on top of the steering wheel on the right side, is back as far as possible toward the driver and the long lever, on top of the steering column controlling the carburetor, is pushed forward about one inch from its retarded position. Fourth: Turn ignition switch to point marked "B" or "M" Fifth: Set the carburetor control on the steering column to the point marked "START." Be sure there is gasoline in the carburetor. Test for this by pressing down on the small pin projecting from the front of the bowl until the carburetor floods. If it fails to flood it shows that the fuel is not being delivered to the carburetor properly and the motor cannot be expected to start. See instructions on page 56 for filling the vacuum tank. Sixth: When it is certain the carburetor has a supply of fuel, grasp the handle of starting crank, push in endwise to engage ratchet with crank shaft pin and turn over the motor by giving a quick upward pull.
Never push down, because if for any reason the motor should kick back, it would endanger the operator. Large engines are multicylinder to reduce pulsations from individual firing strokes, with more than one piston attached to a complex crankshaft. Many small engines, such as those found in mopeds or garden machinery, are single cylinder and use only a single piston, simplifying crankshaft design. A crankshaft is subjected to enormous stresses equivalent of several tonnes of force; the crankshaft is connected to the fly-wheel, the engine block, using bearings on the main journals, to the pistons via their respective con-rods. An engine loses up to 75% of its generated energy in the form of friction and vibration in the crankcase and piston area; the remaining losses occur in blow by. The crankshaft has a linear axis about which it rotates with several bearing journals riding on replaceable bearings held in the engine block; as the crankshaft undergoes a great deal of sideways load from each cylinder in a multicylinder engine, it must be supported by several such bearings, not just one at each end
Tap and die
Taps and dies are tools used to create screw threads, called threading. Many are cutting tools. A tap is used to form the female portion of the mating pair. A die is used to form the male portion of the mating pair; the process of cutting or forming threads using a tap is called tapping, whereas the process using a die is called threading. Both tools can be used to clean up a thread, called chasing. However, using an ordinary tap or die to clean threads will result in the removal of some material, which will result in looser and weaker threads; because of this, threads are cleaned using special taps and dies made for this purpose, which are known as chasers. Chasers are made of softer materials and are not capable of cutting new threads, however they are still tighter fitting than actual fasteners and are fluted like regular taps and dies. One common use is for automotive spark plug threads, which suffer from corrosion and a buildup of carbon. While modern nuts and bolts are made of metal, this was not the case in earlier ages, when woodworking tools were employed to fashion large wooden bolts and nuts for use in winches, windmills and flour mills of the Middle Ages.
As the loads grew heavier and stronger bolts were needed to resist breakage. Some nuts and bolts were measured by the yard; this development led to a complete replacement of wood parts with metal parts of an identical measure. When a wooden part broke, it snapped, ripped, or tore. With the splinters having been sanded off, the remaining parts were reassembled, encased in a makeshift mold of clay, molten metal poured into the mold, so that an identical replacement could be made on the spot. Metalworking taps and dies were made by their users during the 18th and 19th centuries, using such tools as lathes and files for the shaping, the smithy for hardening and tempering, thus builders of, for example, firearms, or textile machinery were to make their own taps and dies. During the 19th century the machining industries evolved and the practice of buying taps and dies from suppliers specializing in them supplanted most such in-house work. Joseph Clement was one such early vendor of taps and dies, starting in 1828.
With the introduction of more advanced milling practice in the 1860s and 1870s, tasks such as cutting a tap's flutes with a hand file became a thing of the past. In the early 20th century, thread-grinding practice went through significant evolution, further advancing the state of the art of cutting screw threads, including those of taps and dies. During the 19th and 20th centuries, thread standardization was evolving with the techniques of thread generation, including taps and dies; the largest tap and die company to exist in the United States was Greenfield Tap & Die of Greenfield, Massachusetts. GTD was so irreplaceably vital to the Allied war effort from 1940–1945 that anti-aircraft guns were placed around its campus in anticipation of possible Axis air attack; the GTD brand is now a part of Widia Products Group. 456+74635843546+6783 A tap cuts or forms a thread on the inside surface of a hole, creating a female surface which functions like a nut. The three taps in the image illustrate the basic types used by most machinists: Bottoming tap or plug tap The tap illustrated in the top of the image has a continuous cutting edge with no taper — between 1 and 1.5 threads of taper is typical.
This feature enables a bottoming tap to cut threads to the bottom of a blind hole. A bottoming tap is used to cut threads in a hole, threaded using one of the more tapered types of tap. In the US, they are known as bottoming taps, but in Australia and Britain they are known as plug taps. Intermediate tap, second tap, or plug tap The tap illustrated in the middle of the image has tapered cutting edges, which assist in aligning and starting the tap into an untapped hole; the number of tapered threads ranges from 3 to 5. Plug taps are the most used type of tap. In the US, they are known as plug taps, whereas in Australia and Britain they are known as second taps. Taper tap The small tap illustrated at the bottom of the image is similar to an intermediate tap but has a more pronounced taper to the cutting edges; this feature gives the taper tap a gradual cutting action, less aggressive than that of the plug tap. The number of tapered threads ranges from 8 to 10. A taper tap is most used when the material to be tapped is difficult to work or the tap is of a small diameter and thus prone to breakage.
Power taps The above taps are referred to as hand taps, since they are, by design, intended to be manually operated. During operation, it is necessary to periodically reverse rotation of a hand tap to break the chip formed during the cutting process, thus preventing an effect called "crowding" that may cause tap breakage; the most common type of power driven tap is the "spiral point" plug tap referred to as a "gun" tap, whose cutting edges are angularly displaced relative to the tap centerline. This feature causes the tap to continuously break the chip and eject it forward into the hole, pre
Crankcase ventilation system
In an internal combustion engine, a crankcase ventilation system is a one way, pressure-sensitive passage which allows the natural build up of gases to escape from the crankcase in a controlled manner. Blow-by, as it is called, is the result of combustion material from the combustion chamber "blowing" past the piston rings and into the rotating assembly's housing. Turbocharged engines are additionally complicated by exhaust leakage from the turbocharger shaft, in some cases, the valve stem seals; these blow-by gases, if not ventilated condense and combine with the oil vapor present in the crankcase, forming sludge or causing the oil to become diluted with unburnt fuel. Excessive crankcase pressure can furthermore lead to engine oil leaks past the crankshaft seals and other engine seals and gaskets. Therefore, it becomes imperative; this allows the blow-by gases to be vented through a PCV valve out of the crankcase. Ventilation leads to the intake manifold, allowing the gases to be recirculated before exiting through the tail pipe.
This method reduces emissions and is known as a closed-loop CVS. Conversely, an open-loop CVS vents directly to the atmosphere through a filter. From the late 19th century through the early 20th, blow-by gases from internal combustion were allowed to find their own way out to the atmosphere past seals and gaskets, it was considered normal for oil to be found both inside and outside an engine, for oil to drip to the ground in small but constant amounts. The latter had been true for steam engines and steam locomotives in the decades before. Bearing and valve designs made little to no provision for keeping oil or waste gases contained. Sealed bearings and valve covers were for special applications only. Gaskets and shaft seals were meant to limit loss of oil, but they were not expected to prevent it. On internal combustion engines, the hydrocarbon-rich blow-by gases would diffuse through the oil in the seals and gaskets into the atmosphere. Engines with high amounts of blow-by would leak profusely via those routes.
The first refinement in crankcase ventilation was the road draft tube, a pipe running from a high location contiguous to the crankcase down to an open end facing down and located in the vehicle's slipstream. When the vehicle is moving, airflow across the open end of the tube creates a draft that pulls gases out of the crankcase; the high location of the engine end of the pipe minimises liquid oil loss. An air inlet path to the crankcase, called the breather and incorporated into the oil filler cap, meant that when a draft was generated at the tube, fresh air swept through the crankcase to clear out the blow-by gases; the road draft tube, though simple, has shortcomings: it does not function when the vehicle is moving too to create a draft, so postal and other slow-moving delivery vehicles tended to suffer rapid buildup of engine sludge due to poor crankcase ventilation. And non-road vehicles such as boats never generated a draft on the tube, no matter how fast they were going. To remedy this situation manufacturers located the breather air filter in the air stream coming from the engine radiator fan, the manufacturers modified the breather to incorporate an air scoop to direct the air into the breather filter so that the engine could be ventilated while the car or truck was standing still.
The draft tube discharged the crankcase gases, composed of unburnt hydrocarbons, directly into the air. This created pollution as well as objectionable odors. Moreover, the draft tube could become clogged with snow or ice, in which case crankcase pressure would build and cause oil leaks and gasket failure. During World War II a different type of crankcase ventilation had to be invented to allow tank engines to operate during deep fording operations, where the normal draft tube ventilator would have allowed water to enter the crankcase and destroy the engine; the PCV system and its control valve were invented to meet this need, but no need for it on automobiles was recognized. In 1952, Professor A. J. Haagen-Smit, of the California Institute of Technology at Pasadena, postulated that unburned hydrocarbons were a primary constituent of smog, that gasoline-powered automobiles were a major source of those hydrocarbons; the GM Research Laboratory discovered in 1958 that the road draft tube was a major source—about half—of the hydrocarbons coming from the automobile.
The PCV system thus became. Positive crankcase ventilation was first factory-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 by voluntary industry action so as not to have to make multiple state-specific versions of vehicles. PCV became standard equipment on all vehicles worldwide because of its benefits not only in emissions reduction but in engine internal cleanliness and oil lifespan. In 1967, several years after its introduction into production, the PCV system became the subject of a U. S. federal grand jury investigation, when it was alleged by some industry critics that the Automobile Manufacturers Association was conspiring to keep several such smog reduction devices on the shelf to delay additional smog control. After eighteen months of investigation by U. S. Attorney Samuel Flatow, the grand jury returned a "no-bill" decision, clearing the AMA, but resulting in a consent decree that all U.
S. automobile companies agreed not to
A die is a specialized tool used in manufacturing industries to cut or shape material using a press. Like molds, dies are customized to the item they are used to create. Products made with dies range from simple paper clips to complex pieces used in advanced technology. Forming dies are made by tool and die makers and put into production after mounting into a press; the die is a metal block, used for forming materials like sheet metal and plastic. For the vacuum forming of plastic sheet only a single form is used to form transparent plastic containers for merchandise. Vacuum forming is considered a simple molding thermoforming process but uses the same principles as die forming. For the forming of sheet metal, such as automobile body parts, two parts may be used: one, called the punch, performs the stretching, and/or blanking operation, while another part, called the die block securely clamps the workpiece and provides similar stretching, and/or blanking operation; the workpiece may pass through several stages using different tools or operations to obtain the final form.
In the case of an automotive component there will be a shearing operation after the main forming is done and additional crimping or rolling operations to ensure that all sharp edges are hidden and to add rigidity to the panel. The main components for die tool sets are: Die block – This is the main part that all the other parts are attached to. Punch plate – This part holds and supports the different punches in place. Blank punch – This part along with the blank die produces the blanked part. Pierce punch – This part along with the pierce die removes parts from the blanked finished part. Stripper plate – This is used to hold the material down on the blank/pierce die and strip the material off the punches. Pilot – This will help to place the sheet for the next stage of operation. Guide, back gauge, or finger stop – These parts are all used to make sure that the material being worked on always goes in the same position, within the die, as the last one. Setting block – This part is used to control the depth that the punch goes into the die.
Blanking dies – See blanking punch Pierce die – See pierce punch. Shank – used to hold in the presses, it should be situated at the center of gravity of the plate. Blanking: A blanking die produces a flat piece of material by cutting the desired shape in one operation; the finished part is referred to as a blank. A blanking die may only cut the outside contour of a part used for parts with no internal features. Three benefits to die blanking are:Accuracy. A properly sharpened die, with the correct amount of clearance between the punch and die, will produce a part that holds close dimensional tolerances in relationship to the part's edges. Appearance. Since the part is blanked in one operation, the finish edges of the part produces a uniform appearance as opposed to varying degrees of burnishing from multiple operations. Flatness. Due to the compression of the blanking process, the end result is a flat part that may retain a specific level of flatness for additional manufacturing operations. Broaching: The process of removing material through the use of multiple cutting teeth, with each tooth cutting behind the other.
A broaching die is used to remove material from parts that are too thick for shaving. Bulging: A bulging die expands the closed end of tube through the use of two types of bulging dies. Similar to the way a chef's hat bulges out at the top from the cylindrical band around the chef's head. Bulging fluid dies: Uses oil as a vehicle to expand the part. Bulging rubber dies: Uses a rubber block under pressure to move the wall of a workpiece. Coining: is similar to forming with the main difference being that a coining die may form different features on either face of the blank, these features being transferred from the face of the punch or die respectively; the coining die and punch flow the metal by squeezing the blank within a confined area, instead of bending the blank. For example: an Olympic medal, formed from a coining die may have a flat surface on the back and a raised feature on the front. If the medal was formed, the surface on the back would be the reverse image of the front. Compound operations: Compound dies perform multiple operations on the part.
The compound operation is the act of implementing more than one operation during the press cycle. Compound die: A type of die that has the die block mounted on a punch plate with perforators in the upper die with the inner punch mounted in the lower die set. An inverted type of blanking die that punches upwards, leaving the part sitting on the lower punch instead of blanking the part through. A compound die allows the cutting of external part features on a single press stroke. Curling: The curling operation is used to roll the material into a curved shape. A door hinge is an example of a part created by a curling die. Cut off: Cut off dies are used to cut off excess material from a finished end of a part or to cut off a predetermined length of material strip for additional operations. Drawing: The drawing operation is similar to the forming operation except that the drawing operation undergoes severe plastic deformation and the material of the part extends around the sides. A metal cup with a detailed feature at the bottom is an example of the difference between formed and drawn.
The bottom of the cup was formed. Extruding: Extruding is the act of deforming blanks of metal called slugs into finished parts such as an aluminum I-beam. Extrusion dies use high pressure from the punch
Internal combustion engine
An internal combustion engine is a heat engine where the combustion of a fuel occurs with an oxidizer in a combustion chamber, an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine; the force is applied to pistons, turbine blades, rotor or a nozzle. This force moves the component over a distance, transforming chemical energy into useful mechanical energy; the first commercially successful internal combustion engine was created by Étienne Lenoir around 1859 and the first modern internal combustion engine was created in 1876 by Nikolaus Otto. The term internal combustion engine refers to an engine in which combustion is intermittent, such as the more familiar four-stroke and two-stroke piston engines, along with variants, such as the six-stroke piston engine and the Wankel rotary engine. A second class of internal combustion engines use continuous combustion: gas turbines, jet engines and most rocket engines, each of which are internal combustion engines on the same principle as described.
Firearms are a form of internal combustion engine. In contrast, in external combustion engines, such as steam or Stirling engines, energy is delivered to a working fluid not consisting of, mixed with, or contaminated by combustion products. Working fluids can be air, hot water, pressurized water or liquid sodium, heated in a boiler. ICEs are powered by energy-dense fuels such as gasoline or diesel fuel, liquids derived from fossil fuels. While there are many stationary applications, most ICEs are used in mobile applications and are the dominant power supply for vehicles such as cars and boats. An ICE is fed with fossil fuels like natural gas or petroleum products such as gasoline, diesel fuel or fuel oil. There is a growing usage of renewable fuels like biodiesel for CI engines and bioethanol or methanol for SI engines. Hydrogen is sometimes used, can be obtained from either fossil fuels or renewable energy. Various scientists and engineers contributed to the development of internal combustion engines.
In 1791, John Barber developed the gas turbine. In 1794 Thomas Mead patented a gas engine. In 1794, Robert Street patented an internal combustion engine, the first to use liquid fuel, built an engine around that time. In 1798, John Stevens built the first American internal combustion engine. In 1807, French engineers Nicéphore and Claude Niépce ran a prototype internal combustion engine, using controlled dust explosions, the Pyréolophore; this engine powered a boat on France. The same year, the Swiss engineer François Isaac de Rivaz built an internal combustion engine ignited by an electric spark. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially. In 1854 in the UK, the Italian inventors Eugenio Barsanti and Felice Matteucci tried to patent "Obtaining motive power by the explosion of gases", although the application did not progress to the granted stage. In 1860, Belgian Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nikolaus Otto patented the first atmospheric gas engine.
In 1872, American George Brayton invented the first commercial liquid-fuelled internal combustion engine. In 1876, Nikolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-cycle engine. In 1879, Karl Benz patented a reliable two-stroke gasoline engine. In 1886, Karl Benz began the first commercial production of motor vehicles with the internal combustion engine. In 1892, Rudolf Diesel developed compression ignition engine. In 1926, Robert Goddard launched the first liquid-fueled rocket. In 1939, the Heinkel He 178 became the world's first jet aircraft. At one time, the word engine meant any piece of machinery—a sense that persists in expressions such as siege engine. A "motor" is any machine. Traditionally, electric motors are not referred to as "engines". In boating an internal combustion engine, installed in the hull is referred to as an engine, but the engines that sit on the transom are referred to as motors. Reciprocating piston engines are by far the most common power source for land and water vehicles, including automobiles, ships and to a lesser extent, locomotives.
Rotary engines of the Wankel design are used in some automobiles and motorcycles. Where high power-to-weight ratios are required, internal combustion engines appear in the form of combustion turbines or Wankel engines. Powered aircraft uses an ICE which may be a reciprocating engine. Airplanes can instead use jet engines and helicopters can instead employ turboshafts. In addition to providing propulsion, airliners may employ a separate ICE as an auxiliary power unit. Wankel engines are fitted to many unmanned aerial vehicles. ICEs drive some of the large electric generators, they are found in the form of combustion turbines in combined cycle power plants with a typical electrical output in the range of 100 MW to 1 GW. The high temperature exhaust is used to superheat water to run a steam turbine. Thus, the efficiency is higher because more energy is extracted from the fuel than what could be extracted by the co