Thursday, August 22, 2019
Quasi Turbine Essay Example for Free
Quasi Turbine Essay 1.INTRODUCTION Quasi turbine is a zero vibration continuous combustion rotary engine having four faces articulated rotor with a free and accessible centre rotating without vibration nor dead time and producing a strong torque at low rpm under a variety of modes and fuels. The quasi turbine is also an optimization theory for extremely compact efficient engine concept. It is a new engine concept from Canada which offers a design similar to that of rotary engines but with the advantages of a gas turbine-all within the confines of a chamber based on the shape of a Saint Hilaire skating rink profile. Each Quasi turbine device is at the cross road of three modern engines: inspired by the turbines: it perfects the piston, and improves on the Wankel. The Quasi turbine results from a research initiated in 1993 aimed at unifying the compression and power turbine into one entity. This invention is a new hybrid engine concept, midway between the piston and the turbine engine which requires relatively few components such as stator with covers, rotating blades, rocking carriages, wheels, and joints. Quasi turbine is also an environmental friendly engine, which provides an engine concept free from atmospheric gas pollution, noise pollution, thermal pollution etc. In this engine efficiency stays constant and optimum no matter the power of the unit. Inventors: Ã¢â¬â Francoise, Gilles, Roxan 2.OBJECTIVES Objective of this invention is to provide a new engine concept unifying the compressor and power turbine into one entity that is a conventional gas turbine engine. Another object of this invention is to provide a low noise, perfectly balanced, zero vibration, low r.p.m engine, giving less time to compression and expansion stroke and allowing more time and volume to the intake combustion stroke. A further objective of this invention is to provide a fast accelerating, zero dead time and to provide an engine almost universal to energy sources, which can run efficiently on pneumatic, steam, hydraulic, liquid and gas fuel internal combustion. Another objective is to provide an engine, which has a short pressure peak, cold intake area characteristics, so that it is suitable for photo detonation mode pure hydrogen fuel combustion. Another objective is to provide a high weight and volume density engine, without need of any valve, check valve or obstruction and within neither a crankshaft nor a flywheel. 3. CONSTRUCTIONAL DETAILS [pic] The invention is an assembly of four carriages supporting the pivots of a four element, variable shape rotor, which is confined within a chamber (internal housing counter wall-stator) based on the shape of a Saint Hilaire skating rink profile. This profile offers the rotary components of the engine a bigger, more uniform radial path, enabling maximum torque to be reached more efficiently than a normal combustion. Two lateral plane covers close the engine end. The rotor is composed of four pivoting blades playing a similar role as the piston or turbine blades. Each pivots sit into one of the four rocking carriages. Each carriage is free to rotate around the same pivot in such a way as to be continuously and precisely in contact with housing counter. A central shaft is not needed for the engine to operate. It can be driven through a set of coupling arms attached to the blades by means of traction slots and through a set of arm braces, the ends of which are linked to central shaft . The central shaft unit can be easily removed through the back cover central hold with out dismantling the engine. Pivoting blades are shaped with the filler tip to allow the control of residual volume in the upper and lower chambers at maximum pressure configuration. Carriage wheels should be wide to reduce contact pressure with the counter wall. For smoother operation, roller bearings are inserted in the bladeÃ¢â¬â¢s hook pivots. Intake, spark plug and exhaust ports are made either radially in the housing, or axial in the side covers, or both. In order to pass along the flame make a continuous combustion engine, a small channel(ignition flame transfer slot) located along the internal housing counter wall next to spark plug allows a voluntary flow back of hot gases into the next ready-to-fire combustion chamber. Screwing or unscrewing the spark plug can control the amount of flow. This channel is called ignition transfer cavity. An ignition-timing advance can be built-in by slightly shifting the effective position of spark plug and / or the channel. To help cooling and reduce lubrication, at least one of the lateral side covers has a large central hole exposing the pivoting blades to central area of the rotor such that all parts of engine are external, except for the carriage and wheels which are always in good thermal contact with the housing contour. Since the seals are the only friction surfaces, the need of lubrication is minimized by an optimal choice of anti-friction materials. The housing, the pivoting blades and the carriages can be made of metal, glass, ceramic or plastic, the later mostly for compressor, pump or water-hydraulic engine application. In a photo-detonation engine because it employs a homogenous charge and compression ignition, it is often described as a HCCI engine . HCCI (Homogeneous charge Compression Ignition) combustion results in Virtually no emissions and superior fuel efficiency. This is because photo detonating engines completely combust the fuel, leaving behind no hydrocarbons to be treated by a catalytic converter or simply expelled into the air. The higher pressure required for Photo-detonation puts a significant amount of stress on the engine itself. Piston engines canÃ¢â¬â¢t withstand the violent force of the detonation. And traditional rotary engines such as the Wankel, which have longer combustion chambers that limit the amount of compression they can achieve, are incapable of producing the high- pressure environment necessary for Photo detonation to occur. The Quasi turbine with carriages is strong enough and compact enough to with stand the force of Photo-detonation and allow for the higher compression ratio necessary for pressure heated self-ignition [pic] QUASI TURBINE SPECIFICATION |SHAFT POWER |ROTOR DIAMETER |ROTOR THICK | | 70 HP | 10cm | 5cm | | 530 HP | 25cm | 10cm | | 4000 HP | 53cm | 20cm | | 33000 HP | 1m | 16inch | | 260000 HP | 2m | 82cm | 4. THE WORKING OF A SIMPLE QUASI TURBINE [pic] The simpler Quasi turbine model looks very much like a traditional rotary engine: A rotor turns inside a nearly oval-shaped housing, Notice, however that the Quasi turbine rotor has four elements instead of three. The sides of the rotor seal against the sides of the housing, and the corners of the rotor seal against the inner periphery, dividing it into four chambers. In a piston engine, one complete four-stroke cycle produces two complete revolutions of the cranks shaft. That means the power output of a piston engine is half a power stroke per one piston revolution. A Quasi turbine engine, on the other hand, doesnÃ¢â¬â¢t need pistons. Instead, the four strokes of a typical piston engine are arranged sequentially round the oval housing. ThereÃ¢â¬â¢s no need for the cranks shaft to perform the rotary conversion a in basic model, itÃ¢â¬â¢s very easy to see the four cycles of internal combustion. Ã¢â¬ ¢ Intake , which draws in a mixture of fuel and air Ã¢â¬ ¢ Compression, which squeezes the fuel air mixture into a smaller volume. Ã¢â¬ ¢ Combustion , which uses a spark from a spark plug to ignite the fuel. Ã¢â¬ ¢ Exhaust, which expels waste gases (the by-products) from the engine. 5. WORKING OF QUASI TURBINE WITH CARRIAGES. [pic] In a Quasi turbine, as the rotor blade turn the volume of the chambers change. First the volume increases, which allows the fuel air-mixture to expand. Then the volume increases, which allows the fuel air-mixture to expand. Then the volume decreases, which compresses the mixture into a smaller space. It is also found that when one combustion stroke is ends then the next combustion stroke is ready to fire. By making a small channel along the internal housing wall next to the spark plug, a small amount of hot gas is allowed to flow back to the next ready to for combustion chamber when each of the carriage seals passes over the channel. The result is continuous combustion, just like in the airplane gas turbine. What all this amounts to the Quasi turbine engine is increased efficiency and performance. The four chambers produce two consecutive circuits. The first circuit is used to compress and expand during combustion . The second is used to expel exhaust and intake air, kin one revolution of the rotor, for power strokes are created. ThatÃ¢â¬â¢s eight times more than a typical piston engine! Even a Wankel engine, which produces three power strokes per rotor revolution, canÃ¢â¬â¢t match the performance of a Quasi turbine . 6. COMPARISON BETWEEN QUASI TURBINE AND WANKEL ENGINE 1. The Wankel engine uses a rigid three-face rotor with a crankshaft. The quasi turbine uses a deformable four faces rotor without a Crankshaft. 2. The Wankel engine shaft turns at three times the rotor RPM. The quasi Turbine rotor and main shaft turns at same RPM Speed. 3. The Wankel engine fires only once per revolution The quasi turbine fires 4 times per main shaft revolution, producing Exceptional torque continuity. 4. When the Wankel engine rotor goes from one T.D.C to next, the Torque increases to a maximum value and starts decreasing right Away (progressive). The torque generated by the quasi turbine gets rapidly to a plateau, and hold this maximum for a long arc before decreasing, giving a better overall mechanical energy conversion rate. 5. The Wankel engine has a dead time. The quasi turbine strokes are consecutive with no dead time. 6. The Wankel engine can not be operated in diesel mode due to the excess expansion volume which adiabatically cools down the combustion. Quasi turbine has no excessive volume and can run in diesel Mode. 7. Due to its one single fire per shaft revolution and the dead time, the Wankel engine needs a flywheel. Quasi turbine does not need a flywheel, and consequently has faster acceleration. 8. Since the Wankel engineÃ¢â¬â¢s shaft rotates at three times its rotor speed, it is not suitable for low rpm compressor or pumps. But quasi turbine is suitable for this. 7.COMPARISON BETWEEN QUASI TURBINE AND CONVENTIONAL TURBINE CONVENTIONAL TURBINE The conventional turbine is a continuous flow engine at intake and exhaust. As the conventional turbine do not convert the pressure forces but rather kinetic energy of rapid flows, it is then necessary to convert the pressure forces in high speed flows by a channeling or by oriental expansion. This intermediatory conversion is particularly complex. And in this case some of energy will be lost mainly due to viscosity, turbulence, and some of thermal conduction of hot gases. The conventional turbine is generally located where the flow is fastest. Also a complete conversion of kinetic energy into mechanical energy is not occurred in a conventional turbine. In many applications one has flow velocity near the sound speed where any instability, impurity or condensate may damage the turbine. QUASI TURBINE As the conventional turbine, the quasi turbine is a continuously flow engine at intake. And exhaust Quasi Turbine, which turns under the effect of static forces and does not make use of hydro or aerodynamic flow properties. Consequently Quasi Turbine converts the potential forces directly into mechanical energy. Because the Quasi Turbine operates under the effect of static forces, it cannot be damaged by saturated steam, by small impurities in the fluid flow. 8. COMPARISON OF QUASI TURBINE AND I.C ENGINE 1. In I.C engine piston makes positive torque only 17% of the time and drag 83% of the time. This is not the case in Quasi turbine. 2. In I.C engine gas flow is not unidirectional, but changes directions with the piston direction. But in Quasi turbine it is unidirectional. 3. In I.C engine valve inertia being a serious limitation to the engine revolution. In Quasi turbine there are no valves. 4. The duration of the piston rest time at top and bottom are without necessarily too long in I.C engines. But it is not the case for Quasi turbine. 5. In I.C engine there is quite important noise level and vibration. But it is not the case for Quasi turbine. 6. In I.C engines accessories like cam shaft uses a substantial power , but in Quasi turbine there is no need of cams 7. In I.C engine lubricant is to be used as heat coolant, which require a Cumbersome oil pan. But Quasi turbine requires no lubrication. | | |Number of expansions In every two | | |Volume of each |revolutions | | |Chamber | | |Piston4 strokes |50cc |1 | |(Gasoline) | | | |Piston 2strokes |50cc |2 | |(Gasoline) | | | |Wankel 4 strokes |50cc |6 | |Qurbine 4strokes |50cc |8 | |(Gasoline) | | | | (Gasoline) Qurbine2strokes |50cc |16 | |Qurbine (steam/pneumatic) |50cc |16 | 9. QUASITURBINE FEATURES 1. Zero vibration In quasi turbine, rotor rotates with a fixed centre of gravity and the Engine is perfectly balanced so there is no chance of vibration. 2. Less noisy For comparable power, the quasi turbine is much quieter than the piston engines, since it splits each expansion into four per turn and evacuates the gases more gradually and on a greater angular displacement 3. Less pollution As the quasi turbine expansion starts quicker than in the other engines, there will be less time for the NOx formation, and less transfer of heat to the engine block. 4. Continuous Combustion with lower temperature Due to an earlier expansion than in he piston engines, initial energy is immediately transferred in to mechanical energy without awaiting the middle of the stroke as in the piston engines. This initial expansion cools immediately the combustion gases, which have less time to transfer their heat to the engine block. So continuous combustion is possible with lower temperature. 5. Better torque continuity and Acceleration The Quasi turbine has jointed torque impulses without the assistance of a flywheel. This gives a better torque continuity for quasi turbine. Flywheel is the main obstacle to engine acceleration. Since Quasi turbine has no fly wheel it gives fast acceleration. 6. More effective conversion into Mechanical energy For a better mechanical energy extraction, compression impulses should be as short as possible. The Quasi turbine has this assymmetry by compressing the mixture in a smaller angular zone and by using a greater angular displacement for the expansion. 7. Not sensitive to detonation Due to the earlier expansion process, quasi turbine reacts better to photo detonation. 8. Compatible with Hydrogen The Quasi turbine meets the fundamental criteria imposed by the Hydrogen engine of the future (that is cold intake area, low sensibility to detonation, less pollutant, robust and energy efficiency). 10. APPLICATIONS 1. Quasi turbine aviation In a propeller airplane, weight reduction allows a larger payload, space saving allows to reduce the aerodynamic drag, absence of vibration increases instruments reliability and flight comfort, the noise reduction increases the discretion level, the high torque allows the use of multi-blades propeller and the better intake characteristic of the Quasi turbine allows higher flight altitude. In a helicopter, a large diameter Quasi turbine could generate enough torque to directly drive of the rotor blades without any gearbox, while making much less noise. So Considering the high power density, the low cross section area and the exceptional intake characteristics of the Quasiturbine, it is reasonable to expect to conceive an airplane engine 2. Quasi turbine Stirling engine In the Quasi turbine Stirling, all the engine shell is pressurized with helium, so that the inter-chambers leaks are automatically recycled by the central region, and required only sealing of a turning shaft (comparatively to the sealing of the back and forth piston connecting rods, unless sealed machines, which the Quasi turbine also can be). The Stirling engines are also known to be large and heavy, which the Quasi turbine-Stirling concept should solve. 3. Quasi turbine pneumatic engine Since the Quasi turbine is a pure expansion engine (which the Wankel is not, neither most of other rotary engines), it is well suitable as compressed fluid engine Air engine or air motor. The pneumatic engine does not show any vibration on the shaft. It does run in heavy smoke or under water as well. 4. Quasi turbine racing car Formula Quasi turbine is a proposal to develop and built of a racing car using the new Quasi turbine. rotary engine. Because the Quasi turbine has a much higher specific power density than the piston engine. A single Quasi turbine. rotor of about 50cm in diameter and 20cm thickness could develop 1000 H.P. at only 3000 rpm. Absence of flywheel would allow much higher acceleration. It is proposed to have the racing car with a differential clutch coupling (no gear box at all). This would much improve the racing cars endurance. 5. Quasi turbine hydrogen engine model A good way to store Hydrogen is to link it with carbon atom. Quasi turbine prefers Hydrogen storage in Carbon molecules. This Hydrogen Carbon molecule storage technique is safe and simple and has been appreciated by humans for centuries under the name of Hydrocarbon fuels. 6. Quasi turbine pumps Quasi turbine is a very compact and light device without Power shaft, which allows to pump large volume. In the pump mode the Quasi turbine has two intakes and two exits. 11.CONCLUSION For over 50 years, researches have been dreaming about the Perfect engine, having uniform combustion, with a small combustion chamber (high compression ratio). This is what the Quasi turbine does by producing much shorter pressure pulses, and further more accepting photo-detonation. Quasi turbine eliminates all the energy wastes occurring in piston and Wankel engine and also it can satisfy modern engine criteria. The research is going on to further improve and develop this highly innovative concept and for creating commercially viable prototypes of Quasi turbine. In future we can see more developments happening in the field of quasi turbine. 12.REFERENCE 1. www.quasiturbine.com 2. www.me.berkeley.edu/cal/QT. 3. http://quasiturbine.promci.qc.ca 4. http//kairos.dsa.uqam.ca/tycoon/Quasiturbine 5. Quasiturbine: Article by Lawrence Tse.