Tonne
The tonne referred to as the metric ton in the United States and Canada, is a non-SI metric unit of mass equal to 1,000 kilograms or one megagram. It is equivalent to 2,204.6 pounds, 1.102 short tons or 0.984 long tons. Although not part of the SI, the tonne is accepted for use with SI units and prefixes by the International Committee for Weights and Measures; the tonne is derived from the weight of 1 cubic metre of pure water. The SI symbol for the tonne is't', adopted at the same time as the unit in 1879, its use is official for the metric ton in the United States, having been adopted by the United States National Institute of Standards and Technology. It is a symbol, not an abbreviation, should not be followed by a period. Use of upper and lower case is significant, use of other letter combinations is not permitted and would lead to ambiguity. For example,'T','MT','Mt','mt' are the SI symbols for the tesla, megatesla and millitonne respectively. If describing TNT equivalent units of energy, this is equivalent to 4.184 petajoules.
In French and most varieties of English, tonne is the correct spelling. It is pronounced the same as ton, but when it is important to clarify that the metric term is meant, rather than short ton, the final "e" can be pronounced, i.e. "tonny". In Australia, it is pronounced. Before metrication in the UK the unit used for most purposes was the Imperial ton of 2,240 pounds avoirdupois or 20 hundredweight, equivalent to 1,016 kg, differing by just 1.6% from the tonne. The UK Weights and Measures Act 1985 explicitly excluded from use for trade certain imperial units, including the ton, unless the item being sold or the weighing equipment being used was weighed or certified prior to 1 December 1980, then only if the buyer was made aware that the weight of the item was measured in imperial units. In the United States metric ton is the name for this unit used and recommended by NIST. Both spellings are acceptable in Canadian usage. Ton and tonne are both derived from a Germanic word in general use in the North Sea area since the Middle Ages to designate a large cask, or tun.
A full tun, standing about a metre high, could weigh a tonne. An English tun of wine weighs a tonne, 954 kg if full of water, a little less for wine; the spelling tonne pre-dates the introduction of the SI in 1960. In the United States, the unit was referred to using the French words millier or tonneau, but these terms are now obsolete; the Imperial and US customary units comparable to the tonne are both spelled ton in English, though they differ in mass. One tonne is equivalent to: Metric/SI: 1 megagram. Equal to 1000000 grams or 1000 kilograms. Megagram, Mg, is the official SI unit. Mg is distinct from milligram. Pounds: Exactly 1000/0.453 592 37 lb, or 2204.622622 lb. US/Short tons: Exactly 1/0.907 184 74 short tons, or 1.102311311 ST. One short ton is 0.90718474 t. Imperial/Long tons: Exactly 1/1.016 046 9088 long tons, or 0.9842065276 LT. One long ton is 1.0160469088 t. For multiples of the tonne, it is more usual to speak of millions of tonnes. Kilotonne and gigatonne are more used for the energy of nuclear explosions and other events in equivalent mass of TNT loosely as approximate figures.
When used in this context, there is little need to distinguish between metric and other tons, the unit is spelt either as ton or tonne with the relevant prefix attached. *The equivalent units columns use the short scale large-number naming system used in most English-language countries, e.g. 1 billion = 1,000 million = 1,000,000,000.†Values in the equivalent short and long tons columns are rounded to five significant figures, see Conversions for exact values.ǂThough non-standard, the symbol "kt" is used for knot, a unit of speed for aircraft and sea-going vessels, should not be confused with kilotonne. A metric ton unit can mean 10 kilograms within metal trading within the US, it traditionally referred to a metric ton of ore containing 1% of metal. The following excerpt from a mining geology textbook describes its usage in the particular case of tungsten: "Tungsten concentrates are traded in metric tonne units (originally designating one tonne of ore containing 1% of WO3, today used to measure WO3 quantities in 10 kg units.
One metric tonne unit of tungsten contains 7.93 kilograms of tungsten." Note that tungsten is known as wolfram and has the atomic symbol W. In the case of uranium, the acronym MTU is sometimes considered to be metric ton of uranium, meaning 1,000 kg. A gigatonne of carbon dioxide equivalent is a unit used by the UN climate change panel, IPCC, to measure the effect of a technolo
Secondary surveillance radar
Secondary surveillance radar is a radar system used in air traffic control, that not only detects and measures the position of aircraft, i.e. bearing and distance, but requests additional information from the aircraft itself such as its identity and altitude. Unlike primary radar systems that measure the bearing and distance of targets using the detected reflections of radio signals, SSR relies on targets equipped with a radar transponder, that replies to each interrogation signal by transmitting a response containing encoded data. SSR is based on the military identification friend or foe technology developed during World War II, therefore the two systems are still compatible. Monopulse secondary surveillance radar, Mode S, TCAS and ADS-B are similar modern methods of secondary surveillance; the rapid wartime development of radar had obvious applications for air traffic control as a means of providing continuous surveillance of air traffic disposition. Precise knowledge of the positions of aircraft would permit a reduction in the normal procedural separation standards, which in turn promised considerable increases in the efficiency of the airways system.
This type of radar can detect and report the position of anything that reflects its transmitted radio signals including, depending on its design, birds and land features. For air traffic control purposes this is both a disadvantage, its targets do not have to co-operate, they only have to be within its coverage and be able to reflect radio waves, but it only indicates the position of the targets, it does not identify them. When primary radar was the only type of radar available, the correlation of individual radar returns with specific aircraft was achieved by the controller observing a directed turn by the aircraft. Primary radar is still used by ATC today as a backup/complementary system to secondary radar, although its coverage and information is more limited; the need to be able to identify aircraft more and reliably led to another wartime radar development, the Identification Friend or Foe system, created as a means of positively identifying friendly aircraft from unknowns. This system, which became known in civil use as secondary surveillance radar, or in the USA as the air traffic control radar beacon system, relies on a piece of equipment aboard the aircraft known as a "transponder."
The transponder is a radio receiver and transmitter pair which receives on 1030 MHz and transmits on 1090 MHz. The target aircraft transponder replies to signals from an interrogator by transmitting a coded reply signal containing the requested information. Both the civilian SSR and the military IFF have become much more complex than their war-time ancestors, but remain compatible with each other, not least to allow military aircraft to operate in civil airspace. Today's SSR can provide much more detailed information, for example, the aircraft altitude, as well as enabling the direct exchange of data between aircraft for collision avoidance. Most SSR systems rely on Mode C transponders; the pressure altitude is independent from the pilot's altimeter setting, thus preventing false altitude transmissions if altimeter is adjusted incorrectly. Air traffic control systems recalculate reported pressure altitudes to true altitudes based on their own pressure references, if necessary. Given its primary military role of reliably identifying friends, IFF has much more secure messages to prevent "spoofing" by the enemy, is used on many types of military platforms including air and land vehicles.
The International Civil Aviation Organization is a branch of the United Nations and its headquarters are in Montreal, Canada. It publishes annexes to the Convention and Annex 10 addresses Standards and Recommended Practices for Aeronautical Telecommunications; the objective is to ensure that aircraft crossing international boundaries are compatible with the Air Traffic Control systems in all countries that may be visited. Volume III, Part 1 is concerned with digital data communication systems including the data link functions of Mode S while volume IV defines its operation and signals in space; the American Radio Technical Commission for Aeronautics and the European Organization for Civil Aviation Equipment produce Minimum Operational Performance Standards for both ground and airborne equipment in accordance with the standards specified in ICAO Annex 10. Both organisations work together and produce common documents. ARINC is an airline run organisation concerned with the form and function of equipment carried in aircraft.
Its main purpose is to ensure competition between manufacturers by specifying the size, power requirements and performance of equipment to be located in the equipment bay of the aircraft. The purpose of SSR is to improve the ability to detect and identify aircraft while automatically providing the Flight Level of an aircraft. An SSR ground station transmits interrogation pulses on 1030 MHz as its antenna rotates, or is electronically scanned, in space. An aircraft transponder within line-of-sight range'listens' for the SSR interrogation signal and transmits a reply on 1090 MHz that provides aircraft information; the reply sent. The aircraft is displayed as a tagged icon on the controller's radar screen at the measured bearing and range. An aircraft without an operating transponder still may be observed by primary radar, but would
Hull number
Hull number is a serial identification number given to a boat or ship. For the military, a lower number implies an older vessel. For civilian use, the HIN is used to trace the boat's history; the precise usage varies by type. For civilian craft manufactured in the United States, the hull number is given to the vessel when it is built and forms part of the hull identification number, which uniquely identifies the vessel and must be permanently affixed to the hull in at least two places. A Hull Identification Number is a unique set of 12 characters, similar to the Vehicle Identification Number, found on automobiles. In 1972, The United States Coast Guard was asked to create a standardized format for HINs to allow for better tracking of accidents and history of boats; this HIN format is as follows: The first three characters consist of the Manufacturers Index Code and should only be letters. The following five characters are the unique serial number assigned by the Manufacturer, can be a series of letters and/or numbers with the exception of the letters O, I, Q.
The last four characters determine the certification year of the boat. The HIN may be found on the aft of the vessel in the uppermost right corner; the HIN may be stated on the title and insurance documents. The United States Navy, United States Coast Guard, United States National Oceanic and Atmospheric Administration employ hull numbers in conjunction with a hull classification symbol to uniquely identify vessels and to aid identification. A particular combination of hull classification and hull number is never reused and therefore provides a means to uniquely identify a particular ship. For example, there have been at least eight vessels named USS Enterprise, but CV-6 uniquely identifies the World War II aircraft carrier from all others. For convenience, the combined designation, painted on the sides of the hulls, is called the "hull number"; the official Navy Style Guide says. The U. S. Navy sometimes ignores the sequence of hull numbering. For example, the Navy built the last Los Angeles-class nuclear submarine as Cheyenne.
Next the Navy built the three Seawolf-class submarines SSN-21 through SSN-23. The Navy resumed the original sequence of hull numbers with USS Virginia for its next class of nuclear attack submarines; this change in numbering was done because the Seawolf class was to have a radical new and large design for the continuation of the Cold War into the 21st century, but cost overruns combined with the end of the Cold War, the resulting reduction of the Navy's construction budget resulted in only three of these boats being constructed: Seawolf and Jimmy Carter. Whenever warships are constructed in American shipyards for foreign navies, any hull numbers used to identify the ships during their construction are never reused by the U. S. Navy. For example, the Perth-class guided missile destroyers that were built for the Royal Australian Navy in Bay City, Michigan were given the hull numbers DDG-25, DDG-26, DDG-27. Several other new warships have been constructed in American shipyards for countries such as West Germany and Taiwan.
Guided-missile frigates were constructed in Portugal under military-assistance aid packages were given the hull numbers DEG 7 through 11. When a naval vessel is modified for use as a different type of ship, it is assigned a new hull number along with its new classification; the actual number remains the same while the hull classification changes. For example, a heavy cruiser, converted into a guided missile cruiser became a CG and its number was changed; this happened with Albany and Columbus, which became CG-10, CG-11, CG-12. During World War II, nine Cleveland-class light cruisers were converted to light aircraft carriers, with different numbers. During the 1970s, the guided missile frigates that were redesignated as guided missile cruisers had their designations changed from DLG to CG; some other guided-missile frigates were redesignated as guided missile destroyers and given new numbers. Hull numbers have been used to identify armored tanks for the U. S. Army and the U. S. Marine Corps, other military services, also.
In Europe, ships are given a Craft Identification Number or Hull Identification Number, standardised as EN ISO 10087:2006. The numbers are a permanent, fourteen-digit alphanumeric identifier issued to all marine vessels in Europe; the numbering system is mandated by the European Recreational Craft Directive and descended from the American system. Larger vessels over 300 gross tons receive a permanent international IMO ship identification number, European vessels over 20 metres receive a permanent ENI number. An example CID/HIN might appear as "GB-ABC00042-A8-99", where "GB" is the ISO 3166-1 country code, "ABC" would be the Acme Boat Company's Manufacturer Identity Code. Months are denoted from A…L for January…December. In the United Kingdom, the British Marine Federation manage the issuing of Manufacturer Identity Code on behalf of the British Department for Business Innovation and Skills. Amateur boat builders in the United Kingdom may apply for one-off HIN from the Royal Yacht Associa
Electronic warfare support measures
In military telecommunications, the terms electronic support or electronic support measures describe the division of electronic warfare involving actions taken under direct control of an operational commander to detect, identify, record, and/or analyze sources of radiated electromagnetic energy for the purposes of immediate threat recognition or longer-term operational planning. Thus, electronic support provides a source of information required for decisions involving electronic protection, electronic attack, avoidance and other tactical employment of forces. Electronic support data can be used to produce signals intelligence, communications intelligence and electronics intelligence. Electronic support measures gather intelligence through passive "listening" to electromagnetic radiations of military interest. Electronic support measures can provide initial detection or knowledge of foreign systems, a library of technical and operational data on foreign systems, tactical combat information utilizing that library.
ESM collection platforms can remain electronically silent and detect and analyze RADAR transmissions beyond the RADAR detection range because of the greater power of the transmitted electromagnetic pulse with respect to a reflected echo of that pulse. United States airborne ESM receivers are designated in the AN/ALR series. Desirable characteristics for electromagnetic surveillance and collection equipment include wide-spectrum or bandwidth capability because foreign frequencies are unknown, wide dynamic range because signal strength is unknown, narrow bandpass to discriminate the signal of interest from other electromagnetic radiation on nearby frequencies, good angle-of arrival measurement for bearings to locate the transmitter; the frequency spectrum of interest ranges from 30 MHz to 50 GHz. Multiple receivers are required for surveillance of the entire spectrum, but tactical receivers may be functional within a specific signal strength threshold of a smaller frequency range. Electronic warfare Electronic countermeasures Low-probability-of-intercept radar AWACS Boeing E-3 Sentry Boeing E-4 Lockheed Orion
Sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect objects on or under the surface of the water, such as other vessels. Two types of technology share the name "sonar": passive sonar is listening for the sound made by vessels. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water. Acoustic location in air was used before the introduction of radar. Sonar may be used in air for robot navigation, SODAR is used for atmospheric investigations; the term sonar is used for the equipment used to generate and receive the sound. The acoustic frequencies used in sonar systems vary from low to high; the study of underwater sound is known as underwater hydroacoustics. The first recorded use of the technique was by Leonardo da Vinci in 1490 who used a tube inserted into the water to detect vessels by ear, it was developed during World War I to counter the growing threat of submarine warfare, with an operational passive sonar system in use by 1918.
Modern active sonar systems use an acoustic transponder to generate a sound wave, reflected back from target objects. Although some animals have used sound for communication and object detection for millions of years, use by humans in the water is recorded by Leonardo da Vinci in 1490: a tube inserted into the water was said to be used to detect vessels by placing an ear to the tube. In the late 19th century an underwater bell was used as an ancillary to lighthouses or light ships to provide warning of hazards; the use of sound to "echo-locate" underwater in the same way as bats use sound for aerial navigation seems to have been prompted by the Titanic disaster of 1912. The world's first patent for an underwater echo-ranging device was filed at the British Patent Office by English meteorologist Lewis Fry Richardson a month after the sinking of the Titanic, a German physicist Alexander Behm obtained a patent for an echo sounder in 1913; the Canadian engineer Reginald Fessenden, while working for the Submarine Signal Company in Boston, built an experimental system beginning in 1912, a system tested in Boston Harbor, in 1914 from the U.
S. Revenue Cutter Miami on the Grand Banks off Newfoundland. In that test, Fessenden echo ranging; the "Fessenden oscillator", operated at about 500 Hz frequency, was unable to determine the bearing of the iceberg due to the 3-metre wavelength and the small dimension of the transducer's radiating face. The ten Montreal-built British H-class submarines launched in 1915 were equipped with Fessenden oscillators. During World War I the need to detect; the British made early use of underwater listening devices called hydrophones, while the French physicist Paul Langevin, working with a Russian immigrant electrical engineer Constantin Chilowsky, worked on the development of active sound devices for detecting submarines in 1915. Although piezoelectric and magnetostrictive transducers superseded the electrostatic transducers they used, this work influenced future designs. Lightweight sound-sensitive plastic film and fibre optics have been used for hydrophones, while Terfenol-D and PMN have been developed for projectors.
In 1916, under the British Board of Invention and Research, Canadian physicist Robert William Boyle took on the active sound detection project with A. B. Wood, producing a prototype for testing in mid-1917; this work, for the Anti-Submarine Division of the British Naval Staff, was undertaken in utmost secrecy, used quartz piezoelectric crystals to produce the world's first practical underwater active sound detection apparatus. To maintain secrecy, no mention of sound experimentation or quartz was made – the word used to describe the early work was changed to "ASD"ics, the quartz material to "ASD"ivite: "ASD" for "Anti-Submarine Division", hence the British acronym ASDIC. In 1939, in response to a question from the Oxford English Dictionary, the Admiralty made up the story that it stood for "Allied Submarine Detection Investigation Committee", this is still believed, though no committee bearing this name has been found in the Admiralty archives. By 1918, Britain and France had built prototype active systems.
The British tested their ASDIC on HMS Antrim in 1920 and started production in 1922. The 6th Destroyer Flotilla had ASDIC-equipped vessels in 1923. An anti-submarine school HMS Osprey and a training flotilla of four vessels were established on Portland in 1924; the U. S. Sonar QB set arrived in 1931. By the outbreak of World War II, the Royal Navy had five sets for different surface ship classes, others for submarines, incorporated into a complete anti-submarine attack system; the effectiveness of early ASDIC was hampered by the use of the depth charge as an anti-submarine weapon. This required an attacking vessel to pass over a submerged contact before dropping charges over the stern, resulting in a loss of ASDIC contact in the moments leading up to attack; the hunter was firing blind, during which time a submarine commander could take evasive action. This situation was remedied by using several ships cooperating and by the adoption of "ahead-throwing weapons", such as Hedgehogs and Squids, which proj
Propeller
A propeller is a type of fan that transmits power by converting rotational motion into thrust. A pressure difference is produced between the forward and rear surfaces of the airfoil-shaped blade, a fluid is accelerated behind the blade. Propeller dynamics, like those of aircraft wings, can be modelled by Bernoulli's principle and Newton's third law. Most marine propellers are screw propellers with fixed helical blades rotating around a horizontal axis or propeller shaft; the principle employed in using a screw propeller is used in sculling. It is part of the skill of propelling a Venetian gondola but was used in a less refined way in other parts of Europe and elsewhere. For example, propelling a canoe with a single paddle using a "pitch stroke" or side slipping a canoe with a "scull" involves a similar technique. In China, called "lu", was used by the 3rd century AD. In sculling, a single blade is moved through an arc, from side to side taking care to keep presenting the blade to the water at the effective angle.
The innovation introduced with the screw propeller was the extension of that arc through more than 360° by attaching the blade to a rotating shaft. Propellers can have a single blade, but in practice there are nearly always more than one so as to balance the forces involved; the origin of the screw propeller starts with Archimedes, who used a screw to lift water for irrigation and bailing boats, so famously that it became known as Archimedes' screw. It was an application of spiral movement in space to a hollow segmented water-wheel used for irrigation by Egyptians for centuries. Leonardo da Vinci adopted the principle to drive his theoretical helicopter, sketches of which involved a large canvas screw overhead. In 1661, Toogood and Hays proposed using screws for waterjet propulsion, though not as a propeller. Robert Hooke in 1681 designed a horizontal watermill, remarkably similar to the Kirsten-Boeing vertical axis propeller designed two and a half centuries in 1928. In 1752, the Academie des Sciences in Paris granted Burnelli a prize for a design of a propeller-wheel.
At about the same time, the French mathematician Alexis-Jean-Pierre Paucton, suggested a water propulsion system based on the Archimedean screw. In 1771, steam-engine inventor James Watt in a private letter suggested using "spiral oars" to propel boats, although he did not use them with his steam engines, or implement the idea; the first practical and applied use of a propeller on a submarine dubbed Turtle, designed in New Haven, Connecticut, in 1775 by Yale student and inventor David Bushnell, with the help of the clock maker and brass foundryman Isaac Doolittle, with Bushnell's brother Ezra Bushnell and ship's carpenter and clock maker Phineas Pratt constructing the hull in Saybrook, Connecticut. On the night of September 6, 1776, Sergeant Ezra Lee piloted Turtle in an attack on HMS Eagle in New York Harbor. Turtle has the distinction of being the first submarine used in battle. Bushnell described the propeller in an October 1787 letter to Thomas Jefferson: "An oar formed upon the principle of the screw was fixed in the forepart of the vessel its axis entered the vessel and being turned one way rowed the vessel forward but being turned the other way rowed it backward.
It was made to be turned by the hand or foot." The brass propeller, like all the brass and moving parts on Turtle, was crafted by the "ingenious mechanic" Issac Doolittle of New Haven. In 1785, Joseph Bramah in England proposed a propeller solution of a rod going through the underwater aft of a boat attached to a bladed propeller, though he never built it. In 1802, Edward Shorter proposed using a similar propeller attached to a rod angled down temporarily deployed from the deck above the waterline and thus requiring no water seal, intended only to assist becalmed sailing vessels, he tested it on the transport ship Doncaster in Gibraltar and at Malta, achieving a speed of 1.5 mph. The lawyer and inventor John Stevens in the United States, built a 25-foot boat with a rotary stem engine coupled to a four-bladed propeller, achieving a speed of 4 mph, but he abandoned propellers due to the inherent danger in using the high-pressure steam engines, instead built paddle-wheeled boats. By 1827, Czech-Austrian inventor Josef Ressel had invented a screw propeller which had multiple blades fastened around a conical base.
He had tested his propeller in February 1826 on a small ship, manually driven. He was successful in using his bronze screw propeller on an adapted steamboat, his ship, Civetta of 48 gross register tons, reached a speed of about 6 knots. This was the first ship driven by an Archimedes screw-type propeller. After a new steam engine had an accident his experiments were banned by the Austro-Hungarian police as dangerous. Josef Ressel was at the time a forestry inspector for the Austrian Empire, but before this he received an Austro-Hungarian patent for his propeller. He died in 1857; this new method of propulsion was an improvement over the paddlewheel as it was not so affected by either ship motions or changes in draft as the vessel burned coal. John Patch, a mariner in Yarmouth, Nova Scotia developed a two-bladed, fan-shaped propeller in 1832 and publicly demonstrated it in 1833, propelling a row boat across Yarmouth Harbour and a small coastal schooner at Saint John, New Brunswick, but his patent application in the United States was rejected until 1849 because he was not an American citizen.
His efficient design drew praise in American scientific circles but by
Diesel engine
The Diesel engine, named after Rudolf Diesel, is an internal combustion engine in which ignition of the fuel, injected into the combustion chamber, is caused by the elevated temperature of the air in the cylinder due to the mechanical compression. Diesel engines work by compressing only the air; this increases the air temperature inside the cylinder to such a high degree that atomised Diesel fuel injected into the combustion chamber ignites spontaneously. With the fuel being injected into the air just before combustion, the dispersion of the fuel is uneven; the process of mixing air and fuel happens entirely during combustion, the oxygen diffuses into the flame, which means that the Diesel engine operates with a diffusion flame. The torque a Diesel engine produces is controlled by manipulating the air ratio; the Diesel engine has the highest thermal efficiency of any practical internal or external combustion engine due to its high expansion ratio and inherent lean burn which enables heat dissipation by the excess air.
A small efficiency loss is avoided compared with two-stroke non-direct-injection gasoline engines since unburned fuel is not present at valve overlap and therefore no fuel goes directly from the intake/injection to the exhaust. Low-speed Diesel engines can reach effective efficiencies of up to 55%. Diesel engines may be designed as either four-stroke cycles, they were used as a more efficient replacement for stationary steam engines. Since the 1910s they have been used in ships. Use in locomotives, heavy equipment and electricity generation plants followed later. In the 1930s, they began to be used in a few automobiles. Since the 1970s, the use of Diesel engines in larger on-road and off-road vehicles in the US has increased. According to Konrad Reif, the EU average for Diesel cars accounts for 50% of the total newly registered; the world's largest Diesel engines put in service are 14-cylinder, two-stroke watercraft Diesel engines. In 1878, Rudolf Diesel, a student at the "Polytechnikum" in Munich, attended the lectures of Carl von Linde.
Linde explained that steam engines are capable of converting just 6-10 % of the heat energy into work, but that the Carnot cycle allows conversion of all the heat energy into work by means of isothermal change in condition. According to Diesel, this ignited the idea of creating a machine that could work on the Carnot cycle. After several years of working on his ideas, Diesel published them in 1893 in the essay Theory and Construction of a Rational Heat Motor. Diesel was criticised for his essay, but only few found the mistake that he made. Diesel's idea was to compress the air so that the temperature of the air would exceed that of combustion. However, such an engine could never perform any usable work. In his 1892 US patent #542846 Diesel describes the compression required for his cycle: "pure atmospheric air is compressed, according to curve 1 2, to such a degree that, before ignition or combustion takes place, the highest pressure of the diagram and the highest temperature are obtained-that is to say, the temperature at which the subsequent combustion has to take place, not the burning or igniting point.
To make this more clear, let it be assumed that the subsequent combustion shall take place at a temperature of 700°. In that case the initial pressure must be sixty-four atmospheres, or for 800° centigrade the pressure must be ninety atmospheres, so on. Into the air thus compressed is gradually introduced from the exterior finely divided fuel, which ignites on introduction, since the air is at a temperature far above the igniting-point of the fuel; the characteristic features of the cycle according to my present invention are therefore, increase of pressure and temperature up to the maximum, not by combustion, but prior to combustion by mechanical compression of air, there upon the subsequent performance of work without increase of pressure and temperature by gradual combustion during a prescribed part of the stroke determined by the cut-oil". By June 1893, Diesel had realised his original cycle would not work and he adopted the constant pressure cycle. Diesel describes the cycle in his 1895 patent application.
Notice that there is no longer a mention of compression temperatures exceeding the temperature of combustion. Now it is stated that the compression must be sufficient to trigger ignition. "1. In an internal-combustion engine, the combination of a cylinder and piston constructed and arranged to compress air to a degree producing a temperature above the igniting-point of the fuel, a supply for compressed air or gas. See US patent # 608845 filed 1895 / granted 1898In 1892, Diesel received patents in Germany, the United Kingdom and the United States for "Method of and Apparatus for Converting Heat into Work". In 1894 and 1895, he filed patents and addenda in various
Italy
