汽车专业 毕业论文 翻译 中英文Quasiturbine Future Trends in Automobile Engine -.doc

This document is available at /QuasiturbineKALPESHPRADHAN0512.doc Seminar ReportQuasiturbine Future Trends in Automobile Engine ByPRADHAN KALPESH HEMANT (B.E MECHANICAL)N.D.M.V.P.S.s COLLEGE OF ENGINEERINGGANGAPUR ROAD, NASIK - 422013 INDIAkalp_ January 2006ABSTRACTThe inventors have made a systematic analysis of engine concepts, their value, their weaknesses, and their potential for improvement. All improvement ideas converged when they suggested making a turbo-shaft turbine having only one turbine in one plane. In order to achieve that, the inventors had to attach the turbine blades one to another in a chain like configuration, where the rotor acts as compressor for a quarter of a turn, and as engine the next quarter of a turn. This is the Quasiturbine! Many researches are going on to increase energy efficiency on the long term with piston, hydrogen, fuel cell. Hybrid concepts are ways to harvest part of the low power efficiency penalty of the piston engine used in vehicle, but counter-productive measures limit the long term perspective until they could efficiently fuel from the electrical grid. None of these solutions are short term stable and competitive.The Quasiturbine in Beau de Rocha (Otto) cycle is a relatively simple technology which could be widely used within a few years with substantial efficiency benefits over piston engines in many applications. Large utility plants convert energy more efficiently than small distributed units and should be favored when possible, but on the long term, the Quasiturbine detonation engine (AC model with carriages) is one of the very few means to match utility efficiency the distributed way, while being as chemically clean as possible.By opposition to dozens of new engine designs, the most important at this time about the Quasiturbine is the fact that it does unknot a new field of development and offers means to achieve what no other engine design has suggested or is able to, and specially for detonation where piston engine has failed for over 40 years.INDEX What is Quasiturbine? How it works? How does it turn? Why is the Quasiturbine Hydrogen Engine superior to conventional IC engine? Advantages of Quasiturbine Applications of Quasiturbine Conclusion References What is Quasiturbine?The Quasiturbine (Qurbine) is a no crankshaft rotary engine having a 4 faces articulated rotor with a free and accessible center, rotating without vibration nor dead time, and producing a strong torque at low RPM under a variety of modes and fuels. The Quasiturbine design can also be used as an air motor, steam engine, gas compressor or pump. The Quasiturbine is also an optimization theory for extremely compact and efficient engine concepts How it WorksIn the Quasiturbine engine, the four strokes of a typical cycle de Beau de Rochas (Otto) cycle are arranged sequentially around a near oval, unlike the reciprocating motion of a piston engine. In the basic single rotor Quasiturbine engine, an oval housing surrounds a four-sided articulated rotor which turns and moves within the housing. 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. Quasiturbine combustion cycle Intake (aqua), Compression (fuchsia), Combustion (red), Exhaust (black). A spark plug is located at the top (green) As the rotor turns, its motion and the shape of the housing cause each side of the housing to get closer and farther from the rotor, compressing and expanding the chambers similarly to the strokes in a reciprocating engine. However, whereas a four stroke piston engine produces one combustion stroke per cylinder for every two revolutions, the chambers of the Quasiturbine rotor generate height combustion strokes per two rotor revolutions; this is eight times more than a four-strokes piston engine. Because the Quasiturbine has no crankshaft, the internal volume variations do not follow the usual sinusoidal engine movements, which provide very different characteristics from the piston or the Wankel engine. Contrary to the Wankel engine where the crankshaft moves the rotary piston face inward and outward, each Quasiturbine rotor face rocks back and forth in reference to the engine radius, but stays at a constant distance from the engine center at all time, producing only pure tangential rotational forces.The four strokes piston has such a long dead time, its average torque is about 1/8 of the peak torque, which dictate the robustness of the piston construction. Since the Quasiturbine has not dead time, average torque is only 30% lower than the peak torque, and for this reason, the relative robustness of the Quasiturbine need be only 1/5 of that of the piston, allowing for an additional engine weight saving. Why does it Turn? This diagram show the force vector in a Quasiturbine when one or two opposed chambers are pressurized either by fuel combustion, or by external pressure fluids. Because the pressure vectors are off center, the Quasiturbine rotor experiences a net rotational force. It is that simple! Quasiturbine as an Imminent SolutionMany researches are going on to increase energy efficiency on the long term with piston, hydrogen, fuel cell. Hybrid concepts are ways to harvest part of the low power efficiency penalty of the piston engine used in vehicle, but counter-productive measures limit the long term perspective until they could efficiently fuel from the electrical grid. None of these solutions are short term stable and competitive.The Quasiturbine in Beau de Rocha (Otto) cycle (Model SC without carriages) is a relatively simple technology which could be widely used within a few years with substantial efficiency benefits over piston engines in many applications. Large utility plants convert energy more efficiently than small distributed units and should be favored when possible, but on the long term, the Quasiturbine detonation engine is one of the very few means to match utility efficiency the distributed way, while being as chemically clean as possible. QT-AC (With carriages) is intended for detonation mode,where high surface-to-volume ratio is a factor attenuating the violence of detonation.By opposition to dozens of new engine designs, the most important at this time about the Quasiturbine is the fact that it does unknot a new field of development and offers means to achieve what no other engine design has suggested or is able to, and specially for detonation where piston engine has failed for over 40 years. Why is the Quasiturbine Hydrogen Engine superior to conventional IC engine?Piston DeficienciesPiston engine deserves respect and should not be arbitrary and globally condemns. However it has deficiencies that no one seems to be willing to list? Here is our list of the main conceptual piston engine deficiencies: The 4 engine strokes should not be of equal duration. The piston makes positive torque only 17 % of the time and drag 83 % of the time. The gas flow is not unidirectional, but changes direction with the piston direction. While the piston descents, the ignition thermal wave front has hard time trying to catch the gas moving in that same direction. The valves open only 20 % of the time, interrupting the flows at intake and at exhaust 80 % of the time. The duration of the piston rest time at top and bottom are without necessity too long. Long top dead center confinement time increase the heat transfer to the engine block reducing engine efficiency. The non-ability of the piston to produce mechanical energy immediately after the top dead center. The proximity of the intake valve and the exhaust valve prevents a good mixture filling of the chamber and the open overlap lets go some un-burnt mixture into the exhaust. The non-ability of the piston to efficiently intakes mixture right after the top dead center. The piston does not stand fuel pre-vaporization, but requires fuel pulverization detrimental to combustion quality and environment. The instantaneous torque impulse is progressive, and would gain to have a plateau. The components use factor is low, and those components would gain to be multifunctional. The average torque is only 15 % of the peak torque, which imposes a construction robustness for the peak 7 times the average. The flywheel is a serious handicap to accelerations and to the total engine weight. The connecting rod gives an oblique push component to the piston, which then requires a lubrication of the piston wall. The lubricant is also heat coolant, which requires a cumbersome pan, and imposes low engine angle orientations. The need of complex set of valves, of came shaft and of interactive synchronization devices. The valves inertia being a serious limitation to the engine revolution. The heavy piston engines require some residual compressed gas before top dead center to cushion the piston return. The internal engine accessories (like the came shaft) use a substantial power. The poor homo-kinetic geometry imposes violent accelerations and stops to the piston. Complete reversal of the flows from intake to exhaust. Quite important noise level and vibration. At low load factor, the intake depressurization of the Otto cycle dissipates power from the engine (vacuum pump against the atmospheric pressure). Without being pretentious, the fact is that the Quasiturbine corrects or improves each of these deficiencies.Side by SideLike the piston engine, the Quasiturbine is a volume modulator of high intensity, and acts as a positive displacement engine. Here is a diagram showing the Piston and the Quasiturbine side by side. Quasiturbine may compare 1 to 1 by displacement, but 1 to 8 by total intake fuel-mixture volume and power, because the chambers are used 8 times more often by revolution.Better torque continuity and acceleration (exceeds even the 2 strokes engines): The crankshaft and the flywheel are the main obstacle to engine acceleration, and since the flywheel are unable to store energy at low rpm, the engine torque at idle is highly handicapped by the engine dead times. The piston of a 4 strokes engine works in power mode about 120 degrees / 720 degrees (2 turns), and thus constitutes a drag 80 % of time, period during which the flywheel assumes a relative torque continuity. The Quasiturbine has jointed torque impulses, and presents a profile of almost flat torque characteristics, without the assistance of a flywheel (Quasiturbine torque continuity would compare to a 16 or more pistons conventional engine).Low revolution - Reduction of gearbox ratio: The gear boxes are evils necessary (expensive, complicated, delicate, and energy consuming). The RPM required by the human activity are generally lower that the performance optimum speed of the engines (e.g.: an automobile wheel generally does not rotate to more than 800 or 1000 RPM, which is 4 to 5 times less than the engine RPM). As the Quasiturbine turns 4 to 5 times less quickly than the other engines (including the Wankel), the gear boxes can often be removed (amongst other things in the field of transport) with an increase in efficiency. Continuous combustion with lower temperature: As the Quasiturbine strokes are jointed (what is not the case with the Wankel), the lighting is necessary only in launching, since the flame transfers itself from one chamber to the following. The thermalisation of the Quasiturbine by contacts with rollers (Model AC) is more effective, and prevents hot point. From the thermal point of view, the Quasiturbine does not contain any internal parts requiring coolant fluid (like oil). Better overlaps: The intake and exhaust ports being at different ends of the combustion chamber, it is possible to do a better filling of the chamber by having a simultaneous open overlapping of the two ports, without risking that a portion of the intake gas goes into the exhaust, as it is the case with the piston engine.Power DensityHere is a table comparing engines (order of magnitude only) on the basis of same combustion chamber volume and same rpm.Quasiturbine model of series AC (with carriages)Same chamber displacement, same rpm.High power density engine: The Wankel is already known as a high power density engine. At comparable power, the Quasiturbine presents an additional reduction of volume. Integrated into a use, the density factor is even more impressive (no flywheel, less gear box ratio, optional central shaft.). Because of its quasi-constant torque, the use factor of the intake and exhaust pipes is 100 % (still better than the Wankel), implying tubes of smaller dimension, etc. Same dynamic power range than piston engines: Just a word to recall that the conventional gas turbines are conceived for a precise aerodynamic flow, and do not offer a wide power range with reasonable efficiency. For its part, the Quasiturbine does not use aerodynamic flow characteristic on the blades, and keeps its excellent efficiency on a wide power range. It is the same when the Quasiturbine is propelled by steam, compressed air, or by fluid flow (Plastic Quasiturbine for hydro-electric centrals, etc).Same range of nominal power: As the piston engines, the Quasiturbines can be made tiny or huge. Due to concept simplicity and the absence of gears, the small units should be still more tiny than piston engines or Wankel. On the other hand, nothing limits the construction of huge Quasiturbines like for ship power, fix power plan stations, or large Quasiturbines for thermal power plan or nuclear, using steam or hydraulic.EfficiencyMore effective conversion into mechanical energy: Engines that use crankshaft generate sinusoidal volume impulses during which the piston stays a relatively long time at the top while it decelerates and reverses direction, and stays briefly at mid-course, which is contrary to the logic of a better engine (Compression impulses should be as short as possible, and the stay at mid-courses the longest possible for a better mechanical energy extraction). On the other hand, the Quasiturbine is more effective because it has less engine accessories to operate (no valve, rocker, push rod, cam, oil pump.). In addition, the piston engine suffers from the symmetry of the back and forth piston movement. Ideally, the piston should have a longer displacement for the expansion (extracting the most possible mechanical energy), and smaller for the admission, without reduction of volume. The Quasiturbine has this asymmetry by compressing the mixture in a smaller angular zone, and by using a greater angular displacement for the expansion. The admission stroke of the piston presents also a major defect in the sense that it is taking-in little volume initially and most at mid course, which does not leave much time to the mixture to enter the cylinders (The role of turbo is essentially to correct this default); for its part the Quasiturbine admits a significant volume initially and leaves much more time to flow for a better effective filling which can even be extended in the next cycle without flow back (In this case, the turbo would be a real improvement, and not a default correction). At the time of the expansion, this same defect of the piston stroke does prevent the piston to extract mechanical energy at the beginning of the stroke, which the Quasiturbine manages to do. Also, with the Quasiturbine the gearbox can often be removed with an increase in efficiency, to which the reduction of weight can also contribute. An other fundamental improvement over the piston is the intake and expansion characteristics. Contrary to the piston which must release its residual pressure at the end of the expansion to avoid counter push, the Quasiturbine asymmetry defines a post-expansion confinement zone in which the residual pressure can be maintained without slowing down the rotation, and during which gas treatment can be done, and the residual energy can be extracted, either through a turbine or in building up a compress gas reserve. Multi-fuel and Multi-modeThe Quasiturbine can be fed (if adapted) by a whole fuel range going from methanol toDiesel oils, including the kerosene, natural gas and possibly hydrogen. The Quasiturbine shows characteristics superior than the 2 strokes engine, with a quality of the exhausts better than the 4 strokes engine. Not sensitive to the detonation: The piston stroke does not allow a rapid increase in the volume of the expansion chamber in the vicinity of the T.D.C., and consequently badly supports the detonation. The Quasiturbine (specially the AC model with carriages) reacts better to the detonation thanks to an earlier expansion process (which means the end of additives to increase the octane rate of gasoline). Moreover, since the blow occurs at the time of the robust square configuration of the blades, and because there is no load transfer on a central shaft, the Quasiturbine is candidate with thedetonation driving mode. Compatible with hydrogen: The high inflammability of hydrogen imposes on hydrogen engine (over 15 % hydrogen) a stratified admission chamber distinct from the combustion chamber (which disqualifies somewhat the piston engines). The Wankel engine success for direct hydrogen combustion comes from its intake and combustion stratification, which results mainly from early intake (like Quasiturbine) and its excessive volume during expansion (with an efficiency lost). The Quasiturbine engine offers the same hydrogen advantage without the lost of efficiency. The Quasiturbine meet