Any engine in which a fuel-air mixture is burned in the engine proper so that the hot gaseous products of combustion act directly on the surfaces of its moving parts, such as those of pistons (see piston and cylinder) or turbine rotor blades. Internal-combustion engines include gasoline engines, diesel engines, gas turbine engines, pure jet engines, and rocket engines and motors, and are one class of heat engines. They are commonly divided into continuous-combustion engines and intermittent-combustion engines. In the first type (e.g., jet engines) fuel and air flow steadily into the engine, where a stable flame is maintained for continuous combustion. In the second (e.g., gasoline – reciprocating-piston engines), discrete quantities of fuel and air are periodically ignited. See also automobile industry, machine, steam engine
Al-Jazari demonstrates an early rotary-to-reciprocating motion, which is a waterwheel-powered pump in 1206.
Leonardo da Vinci described a compressionless engine in 1509.
Christiaan Huygens described a compressionless engine in 1673.
English inventor Sir Samuel Morland used gunpowder to drive water pumps, essentially creating the first
rudimentary internal combustion engine in 17th century.
Alessandro Volta built a toy electric pistol () in which an electric spark exploded a mixture of air and hydrogen, firing a cork from the end of the gun in 1780.
Robert Street built a compressionless engine whose principle of operation would dominate for nearly a century
Swiss engineer François Isaac de Rivaz built an internal combustion engine powered by a mixture of hydrogen
and oxygen in 1806.
Samuel Brown patented the first internal combustion engine to be applied industrially. It was compressionless and based on what Hardenberg
calls the "Leonardo cycle," which, as the name implies, was already out of date at that time in 1823.
French physicist Sadi Carnot established the thermodynamic theory of idealized heat engines. This scientifically established the need for
compression to increase the difference between the upper and lower working temperatures in 1824.
The American Samuel Morey received a patent for a compressionless "Gas or Vapor Engine on 1826 April 1.
A patent was granted to William Barnet (English). This was the first recorded suggestion of in-cylinder compression ON 1838.
The Italians Eugenio Barsanti and Felice Matteucci patented the first working efficient internal combustion engine in London (pt. Num. 1072)
but did not go into production with it. It was similar in concept to the successful Otto Langen indirect engine, but wasn't so well worked out in
detail on 1854.
In Florence at Fonderia del Pignone (now Nuovo Pignone, a subsidiary of General Electric), Pietro Benini realized a working prototype of the
Barsanti-Matteucci engine, supplying 5 HP. In subsequent years he developed more powerful engines—with one or two pistons—which served as steady power sources, replacing steam engines on 1856.
1860: Belgian Jean Joseph Etienne Lenoir (1822–1900) produced a gas-fired internal combustion engine similar in appearance to a horizontal double-acting steam beam engine, with cylinders, pistons, connecting rods, and flywheel in which the gas essentially took the place of the steam. This was the first internal combustion engine to be produced in numbers.
1862: German inventor Nikolaus Otto designed an indirect-acting free-piston compressionless engine whose greater efficiency won the support of Langen and then most of the market, which at that time was mostly for small stationary engines fueled by lighting gas.
1870: In Vienna, Siegfried Marcus put the first mobile gasoline engine on a handcart.
1876: Nikolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, developed a practical four-stroke cycle (Otto cycle) engine. The German courts, however, did not hold his patent to cover all in-cylinder compression engines or even the four-stroke cycle, and after this decision, in-cylinder compression became universal.
1879: Karl Benz, working independently, was granted a patent for his internal combustion engine, a reliable two-stroke gas engine, based on Nikolaus Otto's design of the four-stroke engine. Later, Benz designed and built his own four-stroke engine that was used in his automobiles, which became the first automobiles in production.
1882: James Atkinson invented the Atkinson cycle engine. Atkinson’s engine had one power phase per revolution together with different intake and expansion volumes, making it more efficient than the Otto cycle.
1891: Herbert Akroyd Stuart built his oil engine, leasing rights to Hornsby of England to build them. They built the first cold-start compression-ignition engines. In 1892, they installed the first ones in a water pumping station. In the same year, an experimental higher-pressure version produced self-sustaining ignition through compression alone.
1892: Rudolf Diesel developed his Carnot heat engine type motor burning powdered coal dust.
1893 February 23: Rudolf Diesel received a patent for the diesel engine.
1896: Karl Benz invented the boxer engine, also known as the horizontally opposed engine, in which the corresponding pistons reach top dead center at the same time, thus balancing each other in momentum.
1900: Rudolf Diesel demonstrated the diesel engine in the 1900 Exposition Universelle (World's Fair) using peanut oil (see biodiesel).
1900: Wilhelm Maybach designed an engine built at Daimler Motoren Gesellschaft—following the specifications of Emil Jellinek—who required the engine to be named Daimler-Mercedes after his daughter. In 1902 automobiles with that engine were put into production by DMG.
1908: New Zealand inventor, Ernest Godward started a motorcycle business in Invercargill and fitted the imported bikes with his own invention – a petrol economiser. His economisers worked as well in cars as they did in motorcycles. He invented 72 models of the economiser and by the 1930s was recognised as the world’s leading authority on the internal combustion eng
Engines based on the two-stroke cycle use two strokes (one up, one down) for every power stroke. Since there are no dedicated intake or exhaust strokes, alternative methods must be used to scavenge the cylinders. The most common method in spark-ignition two-strokes is to use the downward motion of the piston to pressurize fresh charge in the crankcase, which is then blown through the cylinder through ports in the cylinder walls.
Spark-ignition two-strokes are small and light for their power output and mechanically very simple; however, they are also generally less efficient and more polluting than their four-stroke counterparts. However, in single-cylinder small motor applications, cc for cc, a two-stroke engine produces much more power than equivalent 4 strokes, due to the enormous advantage of having 1 power stroke for every 360 degrees of crankshaft rotation (compared to 720 degrees in a 4 stroke motor).
Small displacement, crankcase-scavenged two-stroke engines have been less fuel-efficient than other types of engines when the fuel is mixed with the air prior to scavenging, allowing some of it to escape out of the exhaust port. Modern designs (Sarich and Paggio) use air-assisted fuel injection, which avoids this loss, and are more efficient than comparably sized four-stroke engines. Fuel injection is essential for a modern two-stroke engine in order to meet ever stringent emission standards.
Research continues into improving many aspects of two-stroke motors, including direct fuel injection, amongst other things. Initial results have produced motors that are much cleaner burning than their traditional counterparts.
Two-stroke engines are widely used in snowmobiles, lawnmowers, weed-whackers, chain saws, jet skis, mopeds, outboard motors, and many motorcycles.
The largest compression-ignition engines are two-strokes and are used in some locomotives and large ships. These engines use forced induction to scavenge the cylinders. An example of this type of motor is the Wartsila-Sulzer turbocharged 2 stroke diesel as used in large container ships. It is the most efficient and powerful engine in the world, with over 50% thermal efficiency. For comparison, the most efficient small 4-stroke motors are around 43% thermal efficiency (SAE 900648), and size is an advantage for efficiency due to the increase in the ratio of volume to area.
Engines based on the four-stroke or Otto cycle have one power stroke for every four strokes (up-down-up-down) and are used in cars, larger boats, and many light aircraft. They are generally quieter, more efficient, and larger than their two-stroke counterparts. There are a number of variations of these cycles, most notably the Atkinson and Miller cycles. Most truck and automotive diesel engines use a four-stroke cycle, but with a compression heating ignition system. This variation is called the diesel cycle. The steps involved here are:
1. Intake stroke: Air and vaporized fuel are drawn in.
2. Compression stroke: Fuel vapor and air are compressed and ignited.
3. Combustion stroke: Fuel combusts and piston is pushed downwards.
4. Exhaust stroke: Exhaust is driven out.
Engines based on the five-stroke cycle are a variant of the four-stroke cycle. Normally the four cycles are intake, compression, combustion, and exhaust. The fifth cycle added by Delautour is refrigeration. Engines running on a five-stroke cycle are claimed to be up to 30 percent more efficient than equivalent four-stroke engines.
The six stroke engine captures the wasted heat from the 4-stroke Otto cycle and creates steam, which simultaneously cools the engine while providing a free power stroke. This removes the need for a cooling system, making the engine lighter while giving 40% increased efficiency over the Otto Cycle.
Beare Head Technology combines a four-stroke engine bottom end with a ported cylinder, which closely resembles that of a two-stroke: thus, 4+2 = six-stroke. It has an opposing piston that acts in unison with auxiliary low pressure reed and rotary valves, allowing variable compression and a range of tuning options.
In this engine, two diametrically opposed cylinders are linked to the crank by the crank pin that floats on a "triple slipper bearing" (a type of hydrodynamic tilting-pad fluid bearing) that goes through the common Scotch yoke. Unlike the common two-stroke engine, the burnt gases and the incoming fresh air do not mix in the cylinders, contributing to a cleaner, more efficient operation. The Scotch yoke mechanism also prevents side thrust, preventing any piston slap, allowing operation as a detonation or "explosion" engine. This also greatly reduces friction between pistons and cylinder walls. The Bourke engine's combustion phase more closely approximates constant volume combustion than either four-stroke or two-stroke cycles do. It also uses fewer moving parts and has to overcome less friction than conventional crank and slider engines with poppet valves. In addition, its greater expansion ratio means more of the heat from its combustion phase is utilized than in conventional spark ignition engines.
Controlled Combustion Engine
These are also cylinder-based engines, which may be either single- or two-stroke but use, instead of a crankshaft and piston rods, two gear-connected, counterrotating concentric cams to convert reciprocating motion into rotary movement. These cams practically cancel out sideward forces that would otherwise be exerted on the cylinders by the pistons, greatly improving mechanical efficiency.
The number of lobes of the cams (always an odd number not less than 3) determines the piston travel versus the torque delivered. In this engine, there are two cylinders that are180 degrees apart for each pair of counterrotating cams. For single-stroke versions,
There are as many cycles per cylinder pair as there are lobes on each cam, and twice as many for two-stroke engines.
The Wankel engine (rotary engine) does not have piston strokes, so is more properly called a four-phase, rather than a four-stroke, engine. It operates with the same separation of phases as the four-stroke engine, with the phases taking place in separate locations in the engine.
This engine provides three power 'strokes' per revolution per rotor (while it is true that 3 power strokes occur per ROTOR revolution, due to the 3/1 revolution ratio of the rotor to the eccentric shaft, only 1 power stroke per shaft revolution actually occurs), typically giving it a greater power-to-weight ratio than piston engines.
This type of engine is most notably used in the current Mazda RX-8, the earlier RX-7, and other models.
Gas turbines cycles (notably jet engines) do not use the same system to both compress and then expand the gases; instead, separate compression and expansion turbines are employed, giving continuous power. Essentially,
The intake gas (normally air) is compressed and then combusted with a fuel, which greatly raises the temperature and volume. The larger volume of hot gas from the combustion chamber is then fed through the gas turbine, which is then able to power the compressor. The exhaust gas may be used to provide thrust, supplying only sufficient power to the turbine to compress incoming air (jet engine); or as much energy as possible can be supplied to the shaft (gas turbine proper).
In some old noncompressing internal combustion engines: In the first part of the piston downstroke, a fuel/air mixture was sucked or blown in. In the rest of the piston downstroke, the inlet valve closed and the fuel/air mixture fired. In the piston upstroke, the exhaust valve was open. This was an attempt at imitating the way a piston steam engine works. Since the explosive mixture was not compressed, the heat and pressure generated by combustion was much less, causing lower overall efficiency.
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The six-stroke engine is a type of internal combustion engine based on the four-stroke engine, but with additional complexity to make it more efficient and reduce emissions. Two different types of six-stroke engine have been developed since the 1990s:
In the first approach, the engine captures the heat lost from the four-stroke Otto cycle or Diesel cycle and uses it to power an additional power and exhaust stroke of the piston in the same cylinder. Designs use either steam or air as the working fluid for the additional power stroke. The pistons in this type of six-stroke engine go up and down three times for each injection of fuel. There are two power strokes: one with fuel, the other with steam or air. The currently notable designs in this class are the Crower six-stroke engine, invented by Bruce Crower of the U.S. ; the Bajulaz engine by the Bajulaz S.A. company of Switzerland; and the Velozeta Six-stroke engine built by the College of Engineering, at Trivandrum in India.
The second approach to the six-stroke engine uses a second opposed piston in each cylinder that moves at half the cyclical rate of the main piston, thus giving six piston movements per cycle. Functionally, the second piston replaces the valve mechanism of a conventional engine but also increases the compression ratio. The currently notable designs in this class include two designs developed independently: the Beare Head engine, invented by Australian Malcolm Beare, and the German Charge pump, invented by Helmut Kottmann.
Griffin six-stroke engine
In 1883, the Bath-based engineer Samuel Griffin was an established maker of steam and gas engines. He wished to produce an internal combustion engine, but without paying the licensing costs of the Otto patents. His solution was to develop a 'Patent slide valve' and a single-acting six-stroke engine using it.By 1886, Scottish steam locomotive maker Dick, Kerr & Co. saw a future in large oil engines and licensed the Griffin patents. These were double acting, tandem engines and sold under the name "Kilmarnock". A major market for the Griffin engine was in electricity generation, where they developed a reputation for happily running light for long periods, then suddenly being able to take up a large demand for power. Their large heavy construction didn't suit them to mobile use, but they were capable of burning heavier and cheaper grades of oil.
The key principle of the "Griffin Simplex" was a heated exhaust-jacketed external vapouriser, into which the fuel was sprayed. The temperature was held around 550 °F (288 °C), sufficient to physically vapourise the oil but not to break it down chemically. This fractional distillation supported the use of heavy oil fuels, the unusable tars and asphalts separating out in the vapouriser. Hot bulb ignition was used, which Griffin termed the 'Catathermic Igniter' , a small isolated cavity connected to the combustion chamber. The spray injector had an adjustable inner nozzle for the air supply, surrounded by an annular casing for the oil, both oil and air entering at 20 lbs sq in. pressure, and being regulated by a governor.
Griffin went out of business in 1923.
Only two known examples of a Griffin six-stroke engine survive. One is in the Anson engine museum. The other was built in 1885 and for some years was in the Birmingham Museum of Science and Technology, but in 2007 it returned to Bath and the Museum of Bath at Work.
Bajulaz six-stroke engine
The Bajulaz six-stroke engine is similar to a regular combustion engine in design. There are however modifications to the cylinder head, with two supplementary fixed capacity chambers: a combustion chamber and an air preheating chamber above each cylinder.
The combustion chamber receives a charge of heated air from the cylinder; the injection of fuel begins an isochoric burn which increases the thermal efficiency compared to a burn in the cylinder.
The high pressure achieved is then released into the cylinder to work the power or expansion stroke.
Meanwhile a second chamber which blankets the combustion chamber, has its air content heated to a high degree by heat passing through the cylinder wall.
This heated and pressurized air is then used to power an additional stroke of the piston.
The claimed advantages of the engine include reduction in fuel consumption by at least 40%, two expansion strokes in six strokes, multi-fuel usage capability, and a dramatic reduction in pollution.
The Bajulaz Six-Stroke Engine was invented in 1989 by the Bajulaz S A company, based in Geneva, Switzerland; it has U.S. Patent 4,809,511and U.S. Patent 4,513,568
. The Bajulaz six-stroke engine features:
* Reduction in fuel consumption by at least 40%
* Two expansion (work) strokes in six strokes
* Multifuel, including liquefied petroleum gas
* Dramatic reduction in air pollution
* Costs comparable to those of a four-stroke engine
Velozeta six-stroke engine
In a Velozeta engine, during the exhaust stroke, fresh air is injected into the cylinder, which expands by heat and therefore forces the piston down for an additional stroke. The valve overlaps have been removed and the two additional strokes using air injection provide for better gas scavenging.
The engine seems to show 40% reduction in fuel consumption and dramatic reduction in air pollution.Its specific power is not much less than that of a four-stroke petrol engine. The engine can run on a variety of fuels, ranging from petrol and diesel to LPG. An altered engine shows a 65% reduction in carbon monoxide pollution when compared with the four stroke engine from which it was developed.
The Velozeta engine features are:
* Reduction in fuel consumption
* Dramatic reduction in pollution
* Better scavenging and more extraction of work per cycle
* Lower working temperature makes it easy to maintain optimum engine temperature level for better performance
* The six-stroke engine does not require significant modification to existing engines.
* Better cooling due to additional air strokes, which mostly removes the need for a cooling system
* Lighter engine
This six-stroke engine was developed by and awarded the 'Indian Society for Technical Education - National awarded' for Best B. Tech project of 2006. (ISTE/BBSBEC-B.Tech./Award/2006) The technology is being developed by Velozeta, a Technopark (Trivandrum) supported by the National Institute of Technology based in Calicut. Velozeta has been awarded a Phase-I research grant from the Department of Scientific & Industrial Research (Govt. of India) under the Technopreneur Promotion Programme (TePP).
Crower six-stroke engine
In a six-stroke engine developed in the U.S. by Bruce Crower, fresh water is injected into the cylinder after the exhaust stroke, and is quickly turned to superheated steam, which causes the water to expand to 1600 times its volume and forces the piston down for an additional stroke.
This design also claims to reduce fuel consumption by 40%. Maximum efficiency would theoretically be obtained by applying the design to a non-turbocharged diesel engine, where the high compression ratio would allow greater expansion of the steam.
The Crower six-stroke engine was invented in 2004 by 75 year old American inventor Bruce Crower who has applied for a patent on a design involving fresh water injection into the cylinders. As of May 2008, no patent has been awarded.
Leonard Dyer invented the first six-stroke internal combustion water injection engine in 1915, which is very similar to Crower's design.
Crower's six-stroke engine features
* No cooling system required
* Improves a typical engine’s fuel consumption
* Requires a supply of distilled water to act as the medium for the second power stroke.
The term "Six Stroke" was coined by the inventor of the Beare Head, Malcolm Beare. The technology combines a four stroke engine bottom end with an opposed piston in the cylinder head working at half the cyclical rate of the bottom piston. Functionally, the second piston replaces the valve mechanism of a conventional engine.
The M4+2 engines have much in common with the Beare Head engines, combining two opposed pistons in the same cylinder. One piston working at half the cyclical rate of the other. But while the main function of the second piston in a Beare Head engine is to replaces the valve mechanism of a conventional four stroke engine. The M4+2 take the principle one step further.
Two stroke engines are favorites of everyone who wants a really compact engine with lots of power, there are fewer parts and power delivery on every stroke. Of course, the blue haze from the exhaust didn't sit well with the enviro-police so they've pretty much disappeared from use in transportation, but, they are slipping back with new technology applied to the new designs.
EcoMotors has a design called OPOC, Opposed Piston Opposed Cylinder. The design is just what it says, as you can see above, with 2 cylinders and 4 pistons. Peter Hofbauer came up with the idea when he was at Volkswagen, the outboard pistons take the place of the cylinder head and each piston only travels half the distance necessary for the full stroke, allowing higher engine speeds. An electrically controlled turbocharger can be used when necessary with adjustable boost, it can even spin up before the engine starts to give instant boost.
The engine can be built in a modular fashion, allowing more cylinders to be added in pairs with a clutch between the modules so one pair can be used at start or light load with the clutch adding more cylinders when required.
Emissions are said to be very low, meeting EPA standards for both gasoline and diesel configurations.
They're looking for 100 mpg in an automotive application, so just think what you could do with something like this in a motorcycle.