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
  • F02B55/00—Internal-combustion aspects of rotary pistons; Outer members for co-operation with rotary pistons
  • F02B55/16—Admission or exhaust passages in pistons or outer members
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02G—HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS; USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR
  • F02G3/00—Combustion-product positive-displacement engine plants

Definitions

• This invention relates to combustion engines wherein combustion is maintained substantially continuously in a chamber, and the high pressure combustion gas is expanded in a variable volume chamber of the engine to 5 develop torque.
• this principle is a gas turbine, however, they have the disadvantage of a relatively limited operational speed range.
• the restricted speed range results in gas turbines not being acceptable as an alternative to the internal combustion engine in many applications, and particularly
• a continuous combustion engine comprising a housing defining a main chamber, a shaft journalled for rotating in said housing, a piston member disposed within said main chamber and supported on the shaft to rotate on an axis eccentric to the rotation axis of the shaft, said piston member and main chamber being shaped and arranged to define two or more working chambers which vary in volume as the piston member rotates on its axis and that axis rotates about the rotational axis of the shaft, said piston member being operably connected to the shaft to rotate same as the piston member rotates, air inlet and outlet ports • communicating with the main chamber and arranged so each working chamber communicates with the air inlet and outlet port- in sequence as the piston member rotates and the air in the working chamber is compressed as it is conveyed from the inlet to the outlet port, working gas inlet and outlet ports communicating with the main chamber and arranged so each working chamber communicates with the gas inlet and outlet ports in sequence as the piston member rotates and subsequent to communication with the air outlet and
• the opening and closing of the respective ports is controlled by the co-operation of the piston member with the portions of the surface of the main chamber in which the ports are located as the piston member rotates.
• Some of the ports may be arranged in the peripheral surface of the main chamber, and preferably the air inlet port is located in a wall of the chamber normal to the rotor axis.
• the air outlet port communicating the working chambers with the combustion chamber is provided with an automatic or passive type valve which only opens when the pressure in the working chamber is above that in the combustion chamber.
• This valve prevents flow back of combustion gas from the combustion chamber during the initial part of the air compression cycle, when the air pressure in the working chamber is substantially below the combustion chamber pressure.
• the air outlet port may be of a labyrinth construction so that it is uncovered in steps as the edge of the piston member travels across the port. This reduces the communicat ' ion that may occur between the respective adjacent working chamber as the edge of the piston member travels across the port. Such free communication can result in substantial loss of compression pressure.
• valve associated with the air outlet port should be located close to the peripheral surface of the main chamber, that is the axial length of - -
• the port upstream of the valve should be short. Also the temperature lost from the passage leading from the air outlet port to the combustion chamber should be kept to a minimum, such as by insulation of the passage.
• the combustion chamber gases are of very high temperature, and the combustion chamber is not subject to the cooling effects existing in an Otto cycle engine. Accordingly the chamber will be required to be lined with suitable heat resistance materials.
• the gas inlet port from the combustion chamber to the working chamber will be required to be cooled without substantial loss of heat energy. This may, in part, be achieved by arranging the air flow from the air outlet port to the combustion chamber to be in close proximity to the passage leading from the combustion chamber to the gas inlet port.
• the air passage includes an annular .portion disposed about the gas passage so that the heat loss from the combustion gas in the gas passage is maintained at an acceptable temperature, and is, at least partly, taken up y the incoming air to the combustion chamber, and is therefore not a net loss to the heat balance of the engine.
• the basic configuration of the main chamber and piston member may be in the form of a Wankel engine of either the single or multiple rotor type.
• the peripheral surface of the main chamber is epitrochoidal and the piston member is of general triangular shape with the sides of the triangle slightly convex in the direction of the length thereof.
• a seal structure extending across the external peripheral face of the piston to co-operate with the internal peripheral surface of the main chamber.
• Fig. 1 is a diagrammatic cross-sectional view of the housing and piston member of a typical embodiment of the engine of the present invention.
• Figs. 2a to 2f are diagrammatic cross-sections of the engine showing the piston member in various positions throughout an engine cycle.
• Fig. 3 is an enlarged cross-sectional view of the combustion chamber and adjacent engine housing incorporating the air outlet port and gas outlet port.
• 0 Fig. is an exploded view of one construction of a two rotor engine according to the present invention.
• Fig. 5 is a split perspective view of one of the housing in Figure 4 showing the port arrangement.
• Fig. 1 5 there is illustrated diagrammatically in Fig. 1 5 the basic construction of a rotatory engine of the type commonly known as the 'Wankel' rotatory engine and having a port arrangement devised to enable that engine to operate • in accordance with the continuous combustion cycle of the present invention.
• the housing 3 may have any appropriate external shape with an internal cavity 4 of epitrochoidal shape with a peripheral wall .7 and opposite substantially flat end walls 8.
• the piston member 12 is located within the cavity 4 and supported to rotate on the 5 axis 2, eccentric to the axis 6 of the shaft 9.
• the shaft is journal in bearing in the end walls 8 of the cavity 4.
• the piston member 12 is of a generally triangular shape carrying peripheral seals 10 at each corner thereof, engaging with the peripheral wall 7 of the cavity 4, * - * throughout the total movement of the piston member within the cavity.
• End seals 14 are provided in end faces 13 of the piston member 12 to engage the end walls 8 of the cavity 4.
• the main chamber or cavity 4 and piston member 12 define three working chambers 15 which vary in volume as the piston member rotates.
• the internal peripheral wall 7 of the cavity 4 is of a smooth continuous surface in the peripheral direction, and is flat and parallel to the piston axis along any line parallel to the piston axis.
• the triangular shaped peripheral surface of the piston member is made up of three arcuate portions 11, each of which is a smooth continuous convex surface in the peripheral direction, and is flat and parallel to the piston axis along any line parallel to the piston axis.
• the peripheral seal means 10, located at the junctions of the arcuate portions 11 are mounted in respective slots in the piston member.
• the seal means 10 extend transversely of the piston member peripheral surface for the full axial extent thereof, and parallel to the piston member axis.
• the seal means 10 engage in sealing contact the peripheral wall 7 of the cavity 4, and maintain that engagement throughout the movement of the piston member within the cavity 4.
• the seal means 10 thus divide the cavity 4 into three working chambers that vary in volume as the piston member moves in the cavity 4.
• the modification of the engine to operate on the continuous combustion cycle requires the provision of an air inlet port 16 and an air outlet port 17 in the portion of the cavity 4 above the minor axis Y-Y, as seen in Fig. i, and a gas inlet port 18 and gas outlet port 19 on the opposite side or below the minor axis Y-Y.
• the air inlet port 16 is in communication with atmospheric air, preferably through an air filter (not shown) , and the gas outlet port 19 communicates with an engine exhaust system.
• the air outlet port 17 and gas inlet port 18 communicates with a combustion chamber 20.
• a cycle of one working chamber of the engine occupying one revolution of the piston member 12 will be described.
• the piston member is rotating in a clockwise direction as seen in Fig. 2a.
• the peripheral seal 10a on the piston member 12 has just past the air inlet port 16 and so a small working chamber 21 is formed between seal 10a and area X_ of the housing 3.
• the piston member rotates clockwise the volume of the working chamber 21 increase and so air is drawn there into through the port 16 (Fig. 2b).
• the seal 10b passes the air inlet port 16 (Fig. 2c) the seal 10a has passed the air outlet port 17 and is approaching area X express of the housing 3, which is opposite X, on the minor axis of cavity 4.
• Further clockwise movement of the piston member produces a progressive decrease in the volume of the working chamber 21, and a resulting compression of the air therein.
• a check valve (to be described later) in the port 17 opens and air is delivered to the combustion chamber 20 to maintain combustion therein.
• Gas pressure in this engine, while' running, will be substantially constant from ' air outlet port -17 to the gas outlet port 19.
• Power output will be proportional to this gas pressure that is developed in the combustion chamber, which may vary from near atmospheric pressure to a maximum pressure obtainable by an air/fuel ratio which provides stoichiometric -combustion at any specified engine speed.
• An exhaust driven turbocharger may be provided to increase the mass airflow at the air inlet port 16 and so increase the brake mean effective pressure without significantly increasing the combustion temperature.
• peripheral seals 10 mounted in the three corners of the piston member 12, are provided to prevent the passage of air and combustion gas between the working chambers.
• the peripheral seals 10 travel across the ports provided in the internal peripheral surface of the cavity 4, and as the sealing face 40 of the seal 10 is generally narrower than the width of the port, in the direction of movement of the piston member, leakage may occur between working chambers as the peripheral seals pass over the port.
• Fig. 3 is a sectional view of the part of the housing 3 incorporating the air outlet port 17 leading from the working chamber to the combustion chamber.
• the piston member 12 is shown in the position where the seal 10 on the piston member 12 is mid-way in its travel across the port 17.
• the port 17 is divided into a plurality of narrow port openings 42 by the transverse walls 41 , which extend across the full width of • the port 17 parallel to the direction of the seal 10.
• the walls 41 extend.into the port 17 a substantial distance from the peripheral wall 7 of the cavity 4 so that as seal ⁇ o travels across the face of the port, the leakage path between the working' chambers is of a considerable length. That is, that leakage .path is at least twice the length of the walls 41, and is also of a smaller cross-section than exists if the walls 41 were not present.
• the gas outlet port 19 may also be divided into a number of narrow ports opening the same as openings 42 in the port 17 by transverse walls the same as walls 41 in port 17. i a preferred construction the length of the walls 41 in the axial direction of the port 17 is at least 5, conveniently about 10, times the height of the individual openings 40 in the direction of the movement of the seal across the port.
• a typical combustion chamber 20 is shown in Fig. 3 5 having an outer casing 24 designed to withstand forseeable maximum pressures and temperatues . Inside the casing 24 there is provided a smaller diameter combustion chamber liner 22, made of a high temperature resistant steel. An array of holes in various groupings is provided in the
• I-- 1 liner to create the desired airflow pattern to deflect the flame, and hence excessive heat from the liner, and to produce, as near as possible, stoichiometric combustion conditions in the combustion chamber throughout the operating speed range of the engine.
• a floating valve 43 is located at 'the upstream end of the openings 42 in the air outlet port 0 17.
• the valve 43 has limited movement between the ends of the walls 41 and the stop pins 44 on the insert 45.
• the valve 43 closes the openings 42 to prevent a gas flow back to the working chamber from 5 the combustion chamber.
• the valve 43 have a bias towards the position closing the openings 42 such as by a spring loading on the valve 43.
• the air delivered through the air outlet port 17 passes along the passage 44 into the cavity 45 surrounding 0 the duct 46 communicating the combustion chamber 20 with the port 18.
• the air passes from the cavity 45 through ducts 47 into the combustion chamber in the area surrounding the liner 22.
• the incoming air flowing through 5 the cavity 25 and ducts 47 reduces the heat transfer from the duct 46 to the housing 3 while providing cooling of the duct 46 and preheating of the incoming air to the combustion chamber.
• It may be desirable to incorporate devices to control the air flow to the combustion chamber such as a flow limiting sonic choking device in the air outlet port 17, or a pressure differential regulating device in the combustion chamber liner to bypass excessive air downstream of the area of combustion. These devices are particularly useful at high speed and at low power operation.
• Fuel is supplied to the combustion chamber 20 through a nozzle fitted to the combustion chamber at 23, and at a pressure adequate to achieve delivery at all expected combustion chamber pressures, and to produce the required degree of atomization of the fuel for obtaining complete combustion of the fuel.
• the fuel supply system may comprise a positive displacement engine driven pump supplying fuel directly and continuously to the fuel nozzle 26 in the combustion chamber.
• the fuel flow rate will vary from zero "to a maximum as required for stoichiometric combustion at maximum power.
• Fuel flow could be controlled electronically by a "spill” or “bypass” type system controlled by temperature, pressure, and power required, inputs.
• Ignition of the 'atomized fuel is by a spark igniter 24 installed in the combustion chamber.
• This igniter is connected to a high energy capacitor discharge electronic device, and is positioned such that it will initiate combustion at all fuel/air ratios that will be experienced under operating conditions.
• Starting of the engine may be achieved by a traditional electric cranking motor or by releasing stored compressed air into the combustion chamber, while applying fuel and ignition.
• Compressed air could be replenished from a compressor that will be selectively coupled to the engine when running at high power. This stored air could also be released as a supplementary supply to the combustion chamber for increased power output for short periods.
• the engine is shown in an exploded form to reveal the internal components.
• the engine comprises two rotors 50 and 60 and respective rotor housings 51 and 61. Interposed between the housing 51 and 61 is the separator plate 55 which in assembly forms a wall between the rotor housings 51 and 61.
• the opposite end faces 56 and 57 of the separator plate 55 abut the inner end faces 52 and 62 of the housings 51 and 61, and are in sealing engagement with the inner end faces 53 and 63 of the rotors 50 and 60.
• End plates 54 and 64 in assembly abut the outer end faces 58 and 68 of the housings 51 and 61, and are in sealing engagement with the outer end faces 59 and 69 of the rotors.
• Each of the rotors are supported on the crank shaft 70 which is rotatably supported in bearing in the end plates 54,64.
• the eccentric cranks on the crankshaft are 180 out of phase to provide even distribution of the torque inputs from the two rotors to the crankshaft.
• the single combustion chamber 71 receives compressed air from, and supplies combustion gas to, each of the housings 51 and 61 through the air passage 72 and combustion gas passage 73 provided in the separator plate 55.
• the air passage 72 communicates with the passage 74 in the housing 51, which communicates with the air outport 75 the housing 51, which communicates with the air outport 75 and the housing 51 as seen in Fig. 5.
• the air passage 72 similarly communicates with a passage in the housing 61 corresponding to passage 74 in housing 51.
• the combustion gas passage 73 communicates with the passage 76 in the housing 51 which communicates with the gas inlet port 77 as seen in Fig. 5, and similarly communicates with a gas inlet port in housing 61.
• the air inlet ports are not provided in the peripheral wall of the housings, as previously described with reference to Figs. 1 and 2a to 2f, but are provided in the end faces 56 and 57 of the separator plate 55, one air inlet port being shown at 78 in the face 57.
• the port 78 and a corresponding port in the opposite end face 56 each communicate with an air intake duct 79 which in use receives atmospheric air through a suitable air filter (not shown).
• the disposition and shape of the port 78 is selected so that the movement of the seals provided in the end face of the rotor (as indicated at 14 in Fig. 1) will regulate communication of the respective working chambers with atmospheric air as the rotor moves in the housing.
• the provision of the air inlet port in the end wall of the working chamber rather than the peripheral wall provides some advantage in selection of timing of the opening and closing of the air inlet port.
• crankshaft 70 is supported in bearings provided in the end plates 54 and 64, the bearings not being shown in the drawings, but one would be located in the central opening 90 in end plate 64.
• the rotor 60 is supported on the eccentric journal 80 on the crankshaft, and the main journal 81 is supported in a bearing located in the opening 90.
• Each of the rotors 50 and 60 are of the generally triangular shape previously referred to, and are provided at each corner with a perepheral seal 91 extending across the perepheral face of the rotor in a direction parallel to the axis of the rotor, as best seen in rotor 60 in Fig 5.
• seals 9.2 are supported in each opposite end face of the rotor to co-operate in sealing relation with the respective adjacent faces of the end plate and separator plate.
• the seals 92 extend between the seals 91 and are spaced inward from the respective perepheral edges 93 of the rotor and of generally the same contour as said edges.
• each of the air outlet port 95 and gas outlet port 96 are provided with transverse walls 97 and 98 respectively to divide the ports into a number of openings 99 and 100.
• the function of these transverse walls and the relevance thereof to the operation of the engine has been previously discussed with reference to Figure 3.
• the gas inlet port 101 is also shown in Fig.
• the third rotor and chamber define two working chambers, both being expansion chambers.
• One of these expansion chambers would receive combustion gas from the gas outlet port of one of the existing working chambers and the other expansion chamber would receive combustion gas from the gas outlet port of the other existing working chambers.
• these expansion chambers provided by the third rotor and chamber must be of a greater volume than the working chamber from which they receive the combustion gas since they receive that gas at a lower pressure.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Combustion Methods Of Internal-Combustion Engines (AREA)

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• 1985
  • 1985-12-10 EP EP19860900022 patent/EP0203973A1/de not_active Withdrawn
  • 1985-12-10 WO PCT/AU1985/000311 patent/WO1986003558A1/en unknown

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