Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B33/00—Engines characterised by provision of pumps for charging or scavenging
  • F02B33/32—Engines with pumps other than of reciprocating-piston type
  • F02B33/34—Engines with pumps other than of reciprocating-piston type with rotary pumps
  • F02B33/40—Engines with pumps other than of reciprocating-piston type with rotary pumps of non-positive-displacement type
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
  • F01N5/00—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy
  • F01N5/04—Exhaust or silencing apparatus combined or associated with devices profiting by exhaust energy the devices using kinetic energy
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B39/00—Component parts, details, or accessories relating to, driven charging or scavenging pumps, not provided for in groups F02B33/00 - F02B37/00
  • F02B39/02—Drives of pumps; Varying pump drive gear ratio
  • F02B39/04—Mechanical drives; Variable-gear-ratio drives
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B41/00—Engines characterised by special means for improving conversion of heat or pressure energy into mechanical power
  • F02B41/02—Engines with prolonged expansion
  • F02B41/10—Engines with prolonged expansion in exhaust turbines
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
  • F02C5/00—Gas-turbine plants characterised by the working fluid being generated by intermittent combustion
  • F02C5/06—Gas-turbine plants characterised by the working fluid being generated by intermittent combustion the working fluid being generated in an internal-combustion gas generated of the positive-displacement type having essentially no mechanical power output
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02B—INTERNAL-COMBUSTION PISTON ENGINES; COMBUSTION ENGINES IN GENERAL
  • F02B29/00—Engines characterised by provision for charging or scavenging not provided for in groups F02B25/00, F02B27/00 or F02B33/00 - F02B39/00; Details thereof
  • F02B29/04—Cooling of air intake supply
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T10/00—Road transport of goods or passengers
  • Y02T10/10—Internal combustion engine [ICE] based vehicles
  • Y02T10/12—Improving ICE efficiencies
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the present invention relates to a thermal engine of the type comprising a gas generator supplying a turbine engine gas.
• the turbine is connected to a motor shaft which it drives.
• the intended application is in particular the propulsion of aircraft in the aeronautical field.
• a first category of engines includes open cycle engines which are gas turbine engines. In the aeronautical field, they are in the form of turbojets, turboshaft engines or turboprops. Another category includes internal combustion engines such as so-called diesel-ignition engines or spark ignition engines.
• the engines of the second category have specific consumptions better than those of the first. Moreover, the technologies used for the temperatures of the combustion chamber and the high-pressure turbine make the purchase and the maintenance more expensive on these engines.
• turboshaft and turboprop engines can be improved by optimizing the combustion chambers and the efficiency of compressors and turbines, or by using a recovery cycle. However, it can not reach those of internal combustion engines due to a lower cycle efficiency. It is indeed impossible to achieve the same combustion pressures as a diesel engine, in particular because of the thermal limit of the first turbine stage. In addition, the efficiency of gas turbines deteriorates rapidly when deviating from the optimal conditions of adaptation of compressors and turbines.
• the acyclism of piston engines can be treated by dissipative torsion dampers or resonators.
• the torsion dampers are either heavy and complex, see the damping dampers of the DVA type used in the automobile, with dedicated lubrication circuit, or introduce critical rotational speeds, see the resonator dampers, type two-wire pendulums used in general aviation and for motor racing. In any case, it remains difficult to reach the low acyclisms of gas turbines.
• the combustion stability of diesel engines at high altitude can be improved by means of controlled ignition devices, burners or pressurized air supply.
• Free piston engines whose power is recovered on a turbine for driving a propeller have been proposed. Compression and expansion occur on both sides of a double-action piston - a two-stroke diesel cycle - which therefore does not transmit force to a shaft line. Similar solutions have been made for rail and ship applications. However, the architecture of the engine is complex. This solution does not allow the use of modern four-stroke diesel combustion technologies. It is also more thermally demanding because of the two-stroke cycle. It is very little used industrially and more difficult to control because of the noise generated and the reliability.
• the present invention relates to a heat engine combining the advantages of the two categories of engine without the disadvantages. Presentation of the invention
• the heat engine for driving a motor shaft comprising at least one gas generator and a turbine, the gas generator supplying the turbine with engine gas and the turbine rotating the motor shaft.
• the gas generator is a four-stroke internal combustion engine, that it comprises an air supply compressor of the internal combustion engine, the compressor being mechanically driven by the internal combustion engine, and that the turbine is mechanically free with respect to the internal combustion engine.
• the solution is to use a four-stroke engine as a hot gas generator, supplying a free turbine on which the power is taken by a receiver.
• the work of the internal combustion engine is recovered by the compressor.
• This free turbine is powered by the four-stroke engine, in which the high-pressure (HP) expansion and compression phases normally performed on HP compressor and turbine stages on an open-cycle engine are performed.
• HP high-pressure
• the volumetric ratio of the gas generator is thus much lower than that of a conventional internal combustion engine because the expansion phase must not take too much energy to the burnt gases, in order to supply the free turbine with a gas having sufficient pressure and temperature. It takes just enough energy to allow the piston to work on the other three times: exhaust, intake and compression, and to drive the low pressure compressor (LP).
• LP low pressure compressor
• the hot gas generator is a diesel engine.
• the engine comprises as a gas generator a spark ignition internal combustion engine.
• a spark ignition internal combustion engine This one either replaces the diesel engine or is combined with it.
• the compressor is driven by the internal combustion engine via a gearbox and preferably a heat exchanger is disposed between the compressor and the internal combustion engine, or between several stages of the compressor.
• the solution of the invention allows the arrangement of a means for withdrawing air between the compressor and the internal combustion engine.
• a bypass duct is arranged between the compressor and the free turbine. Its purpose is, for example for a high power required, to increase the gas flow thus the work available on the turbine while diluting the hot gases from the internal combustion engine to not exceed the thermal limit of the turbine. It also makes it possible to adapt the operating points of the compressor and the turbine to optimize the overall efficiency.
• an auxiliary combustion chamber is formed between the exhaust of the internal combustion engine and the free turbine, possibly with a bypass duct as mentioned above.
• An additional compressor may also be provided between the exhaust of the internal combustion engine and the auxiliary combustion chamber.
• the auxiliary combustion chamber is thus supplied with a continuous flow by a part or all of the gases coming from the gas generator formed by the internal combustion engine, and possibly by a bypass of the air coming directly from the compressor driven by the combustion engine. internal combustion. In the second configuration, this bypass provides unburned air that allows mixing conditions of the exhaust gases of the gas generator favorable to combustion.
• This chamber is equipped with one or more fuel injectors and possibly one or more igniters for the start-up phases. According to an embodiment for improving the efficiency, the fuel is injected pulses and not continuously, the fuel flow can be injected in phase with the gas puffs from the exhaust of each cylinder.
• the auxiliary combustion chamber can be used during start-up phases to initiate the drive of the compressor.
• this solution advantageously uses the bypass of the air coming from the compressor in order to increase the flow rate and therefore the energy available on the turbine, while the gas generator is still at a standstill or idle.
• shaft of the internal combustion engine being driven by a starter, for example electrical or pneumatic.
• the engine operates as a gas turbine engine.
• the energy recovered by the receiver driven by the free turbine is transmitted to the starting system of the gas generator, to enable it to reach the stabilized idling speed. Once this regime reaches the injection into the auxiliary combustion chamber may be stopped and the air bypass closed.
• the auxiliary combustion chamber also has the function of providing, if necessary, additional power in steady state.
• the combustion of the fuel supplied by the auxiliary injector makes it possible to increase the temperature of the gases coming from the gas generator and thus the power on the turbine and the receiver, independently of the power on the gas generator.
• the unburned air bypass from the compressor may be opened to increase the reactivity of the gas mixture in the auxiliary chamber.
• an additional turbine fed by a portion of the exhaust gas of the internal combustion engine is provided downstream of the exhaust of the internal combustion engine, the shaft of the turbine being mechanically connected to that of the internal combustion engine.
• the described solution makes it possible to obtain low torsional vibrations on the output shaft.
• the flow pulsations related to the alternative operation of the gas generator can be smoothed in a gas manifold.
• Consumption gain compared to an open cycle motor The improvement is obtained on the drive power of the compressor. This power is taken from a gas generator, preferably diesel with better efficiency due to high temperatures and cycle pressures. The efficiency can be further improved by cooling the air after each BP compression stage. Improved weight / power ratio: The large boost reduces the displacement of the gas generator, compared to an internal combustion engine of the same power. In contrast, one gear train is desirable for driving the compressor and another between the free turbine shaft and the receiver.
• the gas generator having a low volumetric ratio, its start is favored by a supply of pressurized air. For this, it is necessary to provide significant energy to the gas generator to drive the compressor. This energy is advantageously derived from the turbine supplied with burnt gases through the auxiliary chamber and the bypass of air coming from the compressor. This turbine is then comparable to a conventional gas turbine. The energy recovered on the receiver is restored to the pneumatic or electric starter of the gas generator. This configuration greatly reduces the need for storage of electrical energy.
• the power input to the turbine by the auxiliary combustion chamber makes it possible to limit the size of the aircraft.
• gas generator at its nominal power, the overall thermal efficiency is degraded during the phases of overpower, because of the lower combustion efficiency of the auxiliary chamber. But these phases are limited in the cycle of use of the engine.
• the reduced dimensions of the gas generator provide a gain in mass and space compared to the same system that would have been sized to allow to achieve the overpower without input of an auxiliary combustion chamber.
• FIG. 1 shows the diagram of a prior art installation with free turbine and gas turbine engine forming the gas generator
• FIG. 3 shows the diagram of an installation according to the invention, comprising an auxiliary combustion chamber.
• the diagram shows a conventional installation 1 with a gas generator 3 and a free turbine 6 driving a receiving machine 7.
• the gas generator comprises on the same shaft compressors 2 with several stages, at low and high pressure, feeding an open-cycle combustion chamber 4, the combustion gases of which are partially released in the turbine 5.
• This turbine drives the compressors 2 by the common shaft.
• the gases are introduced into the free turbine 6 whose shaft is coupled to that of the receiving machine 7 which in the aeronautical field is generally a propeller.
• the cycle is constant pressure combustion in the combustion chamber 4.
• a four-stroke internal combustion engine is substituted for the gas turbine engine for the gas generator.
• the same free turbine 6 drives the receiving machine 7.
• the gas generator 13 comprises an internal combustion engine 14, four times, advantageously a diesel engine. But it could be a spark ignition engine.
• the internal combustion engine 14 conventionally comprises cylinders with which the pistons they contain delimit combustion chambers.
• the pistons are mounted on a crankshaft 20 whose rotation ensures the movement back and forth of the pistons inside the cylinders and the control of the intake and exhaust valves for each chamber.
• each of the cylinders here four, 15, 16, 17 and 18, are successively the four cycle times, namely suction, compression, expansion and exhaust.
• the exhaust of the cylinders communicates with an exhaust manifold 19 which guides the gases, after exhaust of the cylinders, into the gas intake manifold of the free turbine 6.
• the gases are expanded in the turbine 6 and are then evacuated a possible passage through a recuperator, not shown.
• the crankshaft 20 is mechanically connected to a compressor 21 via a gearbox 22 so as to adapt the speed of rotation of the compressor 21 to its own operating speed, which is different from that of the engine. 14.
• the compressor supplies the cylinders with air at as high a pressure as possible, preferably after it has been cooled in a suitable heat exchanger 23
• a bypass duct 25 is arranged between the compressor and the free turbine so as to guide a portion of the air from the compressor directly to the free turbine 6 without passing through the internal combustion engine. It allows for certain phases of operation of the engine such as an additional power demand to increase the flow of gas thus the work available on the turbine while diluting the hot gases from the internal combustion engine to not exceed the thermal limit of the turbine. It also makes it possible to adapt the operating points of the compressor and the turbine to optimize the overall efficiency.
• the volumetric ratio of the gas generator here is much lower than that of a conventional engine because the expansion phase is arranged to take the energy just enough to allow the work of the piston on the other three The majority of the energy of the flue gas is intended to supply the power turbine 6 with sufficient pressure and temperature.
• the gas generator of the installation of FIG. 2 provides a work available on the smaller crankshaft by the reduction of the volumetric ratio.
• the work available on the shaft is reduced to the amount just needed for the compressor drive.
• it provides the same maximum combustion pressure due to a higher compressor outlet pressure than a conventional engine.
• the power transferred to the exhaust gas is higher than in a conventional engine and allows to use the turbine shaft as a motor shaft.
• the internal combustion gas generator As the power is taken on a turbine, it is for the internal combustion gas generator to have enough air flow and pressure, without increasing too much the displacement and thus the mass. This is allowed by feeding cylinders with very high pressure and by reducing the volumetric ratio. Thus, a very high combustion pressure is maintained which allows optimum performance, with a smaller displacement than a diesel engine of the same power. Cooling the air after the compressor also reduces the cubic capacity required. The thermal resistance of the combustion chamber must be guaranteed despite the high compression ratio at the inlet of the cylinders. It should be noted that the four-stroke cycle is less severe from this point of view than a two-stroke cycle.
• Cooling also reduces the work required for compression.
• the solution of the invention allows higher expansion ratios in the free turbine, and a lower air-fuel ratio. This limits the air flow and / or the inlet temperature of the free turbine at equal power.
• an auxiliary combustion chamber is incorporated between the exhaust of the internal combustion engine and the free turbine.
• the gases coming from the internal combustion engine 14 pass into the manifold 19 and feed an auxiliary combustion chamber 30 which is equipped with an auxiliary fuel injector 31 and possibly with an igniter 33.
• the bypass duct The air outlet 25 also opens into the auxiliary combustion chamber 30. It can optionally be connected to the collector 19. The gases coming from the combustion chamber are then directed towards the free turbine 6.
• the injection of fuel into the auxiliary combustion chamber 30 is controlled according to the phase or mode of operation of the engine.
• the gases of the auxiliary combustion chamber thus come either from the cylinders or the bypass 25, or partially from each circuit.
• the gas flow rates of each circuit are controlled by appropriate valves.
• the conduit 25 is for example provided with a valve 26 controlling the diversion of the air coming from the compressor 21.
• a mode of operation at startup is for example the following.
• the internal combustion engine 14 is driven by a not shown starter supplied with electrical or pneumatic energy as the case may be. It drives the compressor that feeds the auxiliary combustion chamber.
• the gases produced drive the turbine which provides, through the receiver 7 and a suitable arrangement, additional energy to the starter. The latter can then drive the internal combustion engine with sufficient power to start it properly.
• a compressor is incorporated between the exhaust of the internal combustion engine and the combustion chamber, or
• an additional turbine is fed by a portion of the exhaust gas of the internal combustion engine, the shaft of the additional turbine being mechanically connected to that of the internal combustion engine.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Supercharger (AREA)
• Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

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Family Applications (1)

Country Status (9)

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Citations (1)

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• 2012
  • 2012-10-11 FR FR1259726A patent/FR2996878B1/fr active Active
• 2013
  • 2013-10-10 RU RU2015116601A patent/RU2015116601A/ru not_active Application Discontinuation
  • 2013-10-10 WO PCT/FR2013/052428 patent/WO2014057227A1/fr active Application Filing
  • 2013-10-10 CA CA2887624A patent/CA2887624A1/fr not_active Abandoned
  • 2013-10-10 CN CN201380056823.XA patent/CN104769250A/zh active Pending
  • 2013-10-10 US US14/434,604 patent/US20150285130A1/en not_active Abandoned
  • 2013-10-10 BR BR112015007930A patent/BR112015007930A2/pt not_active IP Right Cessation
  • 2013-10-10 JP JP2015536211A patent/JP2015531455A/ja active Pending
  • 2013-10-10 EP EP13786702.4A patent/EP2909457A1/fr not_active Withdrawn

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