- 2870 - WANKEL - new auto engine? Wankel rotary engine, invented in the 1950s and used today in sports cars, boats, and some aircraft. In the Wankel, a rounded triangle rotor spins in an eccentric orbit within an oval chamber, with each rotation producing three power strokes, where the engine generates force. New versions of this engine are on the horizon today.
--------------------------- 2870 - WANKEL - new auto engine?
- This review talks about two different revolutions in car engine technology. The first is several years off, but the second technology is right on our door step. Small engines will come first but car engines will follow soon after. Wankel engines started the trend.
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- A car’s engine burns gasoline and converts the energy from the heat of the combusting gasoline into mechanical work. In the process, however, energy is wasted; a typical car only converts around 25 percent of the energy in gasoline into useful energy to make it run. 25% efficiency is nothing to brag about.
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- Engines that run with 100 percent efficiency are still more science fiction than science fact, but new research may bring scientists one step closer to demonstrating an ideal transfer of energy within a car engine, or any engine.
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- Quantum measurement engines are engines that use the principles of quantum mechanics to run with near 100 percent efficiency. This engine could answer important questions about the laws of thermodynamics in quantum systems and contribute to technologies such as more efficient engines and quantum computers.
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- This physics is at the microscopic level today. In the microscopic quantum world today, particles exhibit unique properties that do not align with the classical laws of physics as we know them. The latest research is using superconducting circuits to design experiments that can be carried out within a realistic quantum system. Through these experiments, the researchers are studying how the laws of energy, work, power, efficiency, heat, and entropy function at the “quantum level‘.
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- Quantum measurement engines may work in microscopic environments for very small power tasks such as moving around an atom or charging a miniaturized circuit. In these capacities, they may be important components for quantum computers and learning how to engineer their capabilities
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- The Quantum engine couldn’t currently be used to power a car, because the power in a quantum measurement engine is measured in the unit picowatts, with one picowatt equal to one million millionths of a watt Far from he horsepower needed in a car
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- To make quantum measurement engines for human-scale activities we need to use massive parallelization. Each device only outputs a tiny amount of energy, but by making ‘billions” of them working together, you could make a macroscopic engine from the ground up.
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- This engine could use a new type of fuel. It might be possible to extract work from a system using entanglement as a fuel. “Entanglement“ is a basic of concepts of quantum physics. It uses the properties of one particle that are interlinked with properties of another, even when the particles are separated by a large distance.
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- Using entanglement as a fuel has the possibly revolutionary feature of creating a non-local engine; half of an engine could be in New York, while the other half could be in California. This becomes too weird to fathom.
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- The energy would not be held by either half of the system, yet the two parts could still share energy to fuel both halves proficiently.
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- The engine can, in principle, be perfectly 100% efficient. There would be an ideal transfer of energy from the measurement apparatus to the quantum system.
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- The “Quantum engine” may be a ways off but a new “rotary engine’ from an MIT startup LiquidPiston is already working. It is lighter, quieter, and more efficient than its prior rotary engines.
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- Noise, excessive vibration, and relative inefficiency are drawbacks of the piston-based internal combustion engines that power today’s lawn and garden equipment, such as leaf blowers and lawn trimmers.
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- LiquidPiston has developed a rotary engine that is significantly smaller, lighter, and quieter, as well as 20 percent more fuel-efficient than the gas engines used in many small-engine devices.
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- This engine has no vibration at all and it’s a lot quieter. LiquidPiston’s 70-cubic-centimeter engine produces about 3.5 horsepower at 10,000 RPM; at 4 pounds, and is about 30 percent smaller than the four-stroke, 50-cubic-centimeter piston engines it aims to replace. It could churn out 5 horsepower at 15,000 revolutions per minute, and weighs 3 pounds.
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- The engine runs the novel high-efficiency hybrid cycle achieving combustion at constant volume and overexpansion for greater energy extraction. With only two moving parts, a rotor and shaft, and no valves, commonly used in other four-stroke gas engines to control fuel intake, the engine also has reduced noise and vibration, .
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- Initial applications will be handheld lawn and garden equipment, but later applications will be for mopeds, drones, marine power equipment, robotics, range extenders, and auxiliary power units for boats, planes, and other vehicles. A first step before larger engines to follow.
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- High-efficiency diesel versions of the engine, including the 70-horsepower and the 40-horsepower , for generators will come next.
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- The engine is essentially an upgrade in design and efficiency of the compact Wankel rotary engine, invented in the 1950s and used today in sports cars, boats, and some aircraft.
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- In the Wankel, a rounded triangle rotor spins in an eccentric orbit within an oval chamber, with each rotation producing three power strokes, where the engine generates force.
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- In this new engine an oval rotor spins within a modified, rounded triangular housing that can execute a new thermodynamic cycle and solve all the problems that were plaguing the traditional Wankel engine.
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- A Wankel engine uses a long combustion chamber (like a thin crescent moon), which contributes to poor fuel economy, as the flame can’t reach trailing edges of the chamber and gets quenched by the chamber’s large surface area. This new design has a combustion chamber that is rounder and fatter, so the flame burns over less surface area.
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- Air and fuel intake and gas exhaust can occur through two ports in the rotor, opened or closed as the rotor revolves, removing the need for valves. Asymmetrical location of these ports slightly delays the exhaust process during expansion. This allows for overexpansion process, from the ‘Atkinson thermodynamic cycle“, used in some hybrid cars where gas is expanded in the chamber until there’s no pressure, allowing the engine more time to extract energy from fuel.
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- This design also accommodates a “constant volume combustion”, from the “Otto thermodynamic cycle“, used in spark-ignition piston engines where compressed gas is held in the chamber for an extended period, letting the air and fuel mix ignite completely before expanding, resulting in increased expansion pressures and higher efficiency.
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- It takes a long time to burn fuel in today’s engines. By the time you’re burning fuel, you’re expanding gases, and you’re losing efficiency from the combustion process. This new engine keeps combusting while the rotor is at the top of the chamber and forces combustion under those conditions.
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- For a trial run they replaced the go-kart’s 40-lb engine with our 4-lb, 5 horsepower engine. As of today, you can buy the developer’s kit.
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- The engine is more efficient than a Wankel because 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.
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- Toyota uses the “Atkinson cycle” in its Prius, and that does overexpansion, so it’s not new. But the Prius engine is oversized. A valve train is the camshaft operated system that opens and closes the valves in a piston engine’s combustion chamber to let fuel and air in and exhaust gases out. Turning that shaft consumes energy which is a “parasitic loss” .
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- LiquidPiston’s grapefruit-size, 1.5-kilogram power plant is just the ticket for a medium-duty, propeller-powered drone. That’s why the U.S. military is interested in it.
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- The Wankel has also been suggested as a range extender, 300 miles on a tank of gas. And though LiquidPiston’s engine can claim to be more efficient and more compact than a Wankel, these things may not matter all that much when the machine is working only in a helper mode, small engines, too small for autos.
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- Radical new engine designs crop up all the time, but they rarely make the big time. Remember the gas turbines of the 1960s? The superhot, superefficient ceramic engine of the 1980s? The radically improved two-stroke engine whose exhaust was going to be cleaner than the ambient air? Even the Wankel repeatedly failed until Mazda’s engineers rolled up their sleeves and made its success a priority.
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- The LiquidPiston is the ever-expanding range of uses for engines of all kinds. Even if no car ever runs solely on one of its products, there are plenty of market niches it could fill: hybrids, drones, chain saws, go-carts.
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- October 20, 2020 2870
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--------------------- --- Wednesday, October 21, 2020 ---------------------------
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