Winston
Lorenzo von Matterhorn
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Hope this pans out:
https://liquidpiston.com/news/media-coverage/
[video=vimeo;64911927]https://vimeo.com/64911927[/video]
From various sources:
Its X1 engine is a simple machine with just three moving parts and thirteen major components, but it aims to raise thermal efficiency from the 20 percent of a normal gas engine to more than 50 percent, with drastic reductions in weight and size. How? By wasting much less energy during the course of an combustion cycle.
"We stretched the performance curves in every direction to get much higher efficiency," said Alec Shkolnik, President and CEO of LiquidPiston, "We took the best parts of many different thermal cycles and combined them." The design is theoretically capable of 75 percent thermal efficiency, but the group is targeting 57 percent in real world applications, still a huge jump.
The basic idea is similar to a Wankel rotary, but turned on its head. Where the rotor holds the seals in a normal Wankel, the housing does that job in the X1 engine. This allows significant reduction in oil consumption over a regular rotary motor.
Other enhancements include direct injection, a high compression ratio at 18:1, and a dramatic change to the geometry of the combustion chamber, which maintains a constant volume during ignition. This change means the air-fuel mixture auto-ignites like a diesel, and can be burned much longer than normal. The result is a more complete combustion ending in low emissions and very high chamber pressures. This high pressure is allowed to act on the rotor until it reaches nearly atmospheric pressures, so almost all the available energy is extracted before the exhaust is physically pushed out. Again, this is different than a normal internal combustion engine, which releases very energetic, high-pressure exhaust gas.
Some other slick features: Since the engine is designed to convert so much more heat energy into mechanical force, less heat has to be removed from the block, so there's actually no water cooling system. In cases where the engine is under load and needs to cool down, it can skip a fuel injection event and just suck in cool air, which is then heated by the block and gets exhausted. Another option is to inject water into the combustion chamber. This has three effects: cooling the engine, reducing NOx emissions, and converting some of the water to steam, which increases power.
LiquidPiston emerged in 2003, when the Shkolniks invented the high-efficiency hybrid cycle, or HEHC, a motor based on a four-stroke thermodynamic cycle. The men named the company LiquidPiston because they had initially planned to use liquid-piston technology similar to that found on the Humphrey pump. Used in large-scale water-supply projects in the early 20th century, the pump operated by compressing a mixture of flammable gas and air with a cylinder of water. But no LiquidPiston engine, including its current Mini X, has ever used an actual liquid piston.
The engine is... the fruit of a dozen-odd years of work by LiquidPiston, a startup co-founded by Alec Shkolnik, who has a Ph.D. in computer science, with a specialization in AI and modeling. The engine itself is based on combustion technology developed by his father, Nikolay, a Soviet-trained mechanical engineer who retrained in the United States as a physicist.
Its kind of a Wankel flipped inside out, a design that solves the old problems with sealing and fuel consumption, says company founder Alec Shkolnik. The Wankel has a triangular rotor inside a peanut-shaped housing; we have a peanut-shaped rotor inside a triangular housing. Our seals go at the apexes of the triangle [...] and our seals are stationary because theyre in the housing.
The seals stop gas from moving from one chamber to another. In a Wankel, the seals move rapidly, and that makes them hard to lubricate. You have to spray oil into the combustion chamber knowing that only a fraction will reach the seals and the rest will go up in smokea problem for both fuel economy and engine emissions. LiquidPistons engine lacks that baggage but retains the rotary engines intrinsic mechanical simplicityjust a rotor and an eccentric shaft, together with fuel injectors, fuel pumps and oil pumps.
The engine is more efficient than a Wankel becaues it has a higher compression ratio and because the shifting geometry of its internal cavities lets it extract most of the energy of the exhaust gases before voiding them, a feature called over-expansion.
Toyota uses the Atkinson cycle in its Prius, and that does overexpansionso its not new, he says. But the Prius engine is oversized. We get over-expansion almost for free, just by changing the location of our [valve] port. We dont have to have clunky valve trains to achieve that.
LiquidPistons [current] grapefruit-size, 1.5-kilogram power plant is just the ticket for a medium-duty, propeller-powered drone. Thats why the U.S. military is interested in it: the company has received [$1 million] funding from the Defense Advanced Military Research Projects Agency, or DARPA.
https://liquidpiston.com/news/media-coverage/
[video=vimeo;64911927]https://vimeo.com/64911927[/video]
From various sources:
Its X1 engine is a simple machine with just three moving parts and thirteen major components, but it aims to raise thermal efficiency from the 20 percent of a normal gas engine to more than 50 percent, with drastic reductions in weight and size. How? By wasting much less energy during the course of an combustion cycle.
"We stretched the performance curves in every direction to get much higher efficiency," said Alec Shkolnik, President and CEO of LiquidPiston, "We took the best parts of many different thermal cycles and combined them." The design is theoretically capable of 75 percent thermal efficiency, but the group is targeting 57 percent in real world applications, still a huge jump.
The basic idea is similar to a Wankel rotary, but turned on its head. Where the rotor holds the seals in a normal Wankel, the housing does that job in the X1 engine. This allows significant reduction in oil consumption over a regular rotary motor.
Other enhancements include direct injection, a high compression ratio at 18:1, and a dramatic change to the geometry of the combustion chamber, which maintains a constant volume during ignition. This change means the air-fuel mixture auto-ignites like a diesel, and can be burned much longer than normal. The result is a more complete combustion ending in low emissions and very high chamber pressures. This high pressure is allowed to act on the rotor until it reaches nearly atmospheric pressures, so almost all the available energy is extracted before the exhaust is physically pushed out. Again, this is different than a normal internal combustion engine, which releases very energetic, high-pressure exhaust gas.
Some other slick features: Since the engine is designed to convert so much more heat energy into mechanical force, less heat has to be removed from the block, so there's actually no water cooling system. In cases where the engine is under load and needs to cool down, it can skip a fuel injection event and just suck in cool air, which is then heated by the block and gets exhausted. Another option is to inject water into the combustion chamber. This has three effects: cooling the engine, reducing NOx emissions, and converting some of the water to steam, which increases power.
LiquidPiston emerged in 2003, when the Shkolniks invented the high-efficiency hybrid cycle, or HEHC, a motor based on a four-stroke thermodynamic cycle. The men named the company LiquidPiston because they had initially planned to use liquid-piston technology similar to that found on the Humphrey pump. Used in large-scale water-supply projects in the early 20th century, the pump operated by compressing a mixture of flammable gas and air with a cylinder of water. But no LiquidPiston engine, including its current Mini X, has ever used an actual liquid piston.
The engine is... the fruit of a dozen-odd years of work by LiquidPiston, a startup co-founded by Alec Shkolnik, who has a Ph.D. in computer science, with a specialization in AI and modeling. The engine itself is based on combustion technology developed by his father, Nikolay, a Soviet-trained mechanical engineer who retrained in the United States as a physicist.
Its kind of a Wankel flipped inside out, a design that solves the old problems with sealing and fuel consumption, says company founder Alec Shkolnik. The Wankel has a triangular rotor inside a peanut-shaped housing; we have a peanut-shaped rotor inside a triangular housing. Our seals go at the apexes of the triangle [...] and our seals are stationary because theyre in the housing.
The seals stop gas from moving from one chamber to another. In a Wankel, the seals move rapidly, and that makes them hard to lubricate. You have to spray oil into the combustion chamber knowing that only a fraction will reach the seals and the rest will go up in smokea problem for both fuel economy and engine emissions. LiquidPistons engine lacks that baggage but retains the rotary engines intrinsic mechanical simplicityjust a rotor and an eccentric shaft, together with fuel injectors, fuel pumps and oil pumps.
The engine is more efficient than a Wankel becaues it has a higher compression ratio and because the shifting geometry of its internal cavities lets it extract most of the energy of the exhaust gases before voiding them, a feature called over-expansion.
Toyota uses the Atkinson cycle in its Prius, and that does overexpansionso its not new, he says. But the Prius engine is oversized. We get over-expansion almost for free, just by changing the location of our [valve] port. We dont have to have clunky valve trains to achieve that.
LiquidPistons [current] grapefruit-size, 1.5-kilogram power plant is just the ticket for a medium-duty, propeller-powered drone. Thats why the U.S. military is interested in it: the company has received [$1 million] funding from the Defense Advanced Military Research Projects Agency, or DARPA.