Patent Grant
7793635
The present invention relates to a rotary piston type internal combustion engine and particularly relates to a unidirectional rotary engine in which an annular operation chamber is formed by one or both of sidewall portions of a rotor in the axial direction of the output shaft and a housing; the rotor comprises at least one pressuring/pressured member that partitions the annular operation chamber, and the housing comprises at least one operation chamber partitioning member, thereby realizing downsizing, high output power, and improved combustion and output performance and sealing and lubricating properties.
Reciprocating piston engines are extensively used because of their excellent combustion gas sealing and lubricating properties. However, the reciprocating engine tends to have a complex structure, be large in size, has high production cost, and cause vibrations. It is difficult to realize complete combustion in a reciprocating engine because the available combustion strokes depend on a crank angle not greater than 180 degrees. Furthermore, the crank mechanism properties set an upper limit on the conversion efficiency from combustion gas pressure to output power (torque, horsepower). The crank radius is determined according to the cylinder capacity. It is difficult to increase the crank radius and, accordingly, the output performance. In addition, in the case of a four-cycle engine, every two rotations of the crank shaft create one combustion stroke, hampering downsizing of the engine. In order to deal with this, the engine rotation speed is increased for higher output horsepower. This is disadvantageous because combustion performance is reduced as the engine rotation speed is increased.
Over the past 130 years or so, various rotary engines (rotary piston type internal combustion engines) have been proposed. However, they are all imperfect except for the Wankel rotary engine. Rotary engines are divided into two major groups including: a unidirectional rotary engine in which the rotor does not have an eccentric motion and the Wankel rotary engine in which the rotor has eccentric motion.
Approximately 12 years ago, the inventor of the present application proposed an unidirectional rotary piston type rotary engine cited in Patent Document 1, which has an annular operation chamber outside the outer periphery of the rotor. The rotor comprises a pressuring/pressured member partitioning the annular operation chamber. The housing comprises first and second oscillating partitions that partition the annular operation chamber, wherein the first partition opens/closes an auxiliary combustion chamber. Two sets of spring assemblies for elastically biasing the first and second partitions are respectively provided.
With this rotary engine, the annular operation chamber formed outside the outer periphery of the rotor and the two sets of spring assemblies make the engine greater in size. The first and second partitions and rotor make line-contact, not area-contact, with problems relating to hermetic sealing and lubricating properties.
Conversely, Patent Documents 2 to 5 have proposed various unidirectional rotary piston type rotary engines. The rotary engine described in Patent Document 2 has an approximately 240 degrees arc-shaped intake/compression groove formed on a sidewall of the rotor, a partition biased by a spring and partitioning the intake/compression groove, an arc-shaped expansion/exhaust groove formed on the outer periphery of the rotor, and a compression/explosion chamber formed in a protrusion of the housing.
The rotary engine of Patent Document 3 is a vane type rotary engine having a rotor eccentrically installed in the circular retention hole of a housing, an output shaft passing through the center of the rotor, eight vanes mounted on the rotor in a radially reciprocating manner, and an auxiliary combustion chamber formed on the outer periphery side of the circular retention hole.
The rotary engine of Patent Document 4 has a rotor concentrically installed in the circular retention hole of a housing, an intake groove formed by cutting out the outer periphery of the rotor into an arc (a crescent) shape, a partition mounted on the housing and abutting the outer periphery of the rotor, and a cam mechanism for radially moving the partition.
The rotary engine of Patent Document 5 has a housing, a nearly oval rotor retained in a circular retention chamber in the housing, two partitions biased by springs, a timing rotor retained in a circular hole situated next to the circular retention chamber via an middle side plate, an arc-shaped main combustion chamber formed on the outer periphery of the timing rotor, an auxiliary combustion chamber formed outside the outer periphery of the main combustion chamber, a heating plug facing the auxiliary combustion chamber, and a secondary injection nozzle. Fuel-air mixture pressurized by the rotor in the intake/compression chamber is introduced into the auxiliary combustion chamber, where it is compressed and ignited. The combustion gas is introduced into the expansion/exhaust chamber among the circular retention chambers via the main combustion chamber, enabling the combustion gas to work on the rotor.
It is difficult to maintain sealing property or ensure lubricating property in supplying lubricating oil to the sliding parts and durability in a structure in which the forefront of an oscillating partition that partitions the operation chamber makes line-contact with the outer periphery of the rotor for hermetic sealing as in the rotary engine of Patent Document 1. The rotary engine of Patent Document 2 has an expansion/exhaust groove (combustion operation chamber) on the outer periphery side of the rotor, which enlarges the engine. The combustion stroke spans over a rotation angle of approximately 120 degrees of the output shaft; therefore, making it difficult to achieve complete combustion. The rotor receives not only forward rotational torque but also reverse rotational torque in the later stage of the combustion stroke, which does not improve output performance. Furthermore, the compression/explosion section largely protruding upward, increasing the height of the engine. The arc-shaped intake/compression groove is formed on the rotor sidewall; however, the combustion operation chamber is not, with ineffective use of the space on the rotor sidewall.
The rotary engine of Patent Document 3 has the operation chamber on the outer periphery side of the rotor, increasing the engine size. Forward rotation torque is generated to drive the rotor while the engine rotates. Combustion gas within vane cells between vanes generates not only forward rotation torque but also large reverse rotation torque, making it difficult to increase the output performance.
The rotary engine of Patent Document 4 has the combustion operation chamber on the outer periphery of the rotor, which increases the engine in size. The cylindrical partition makes line-contact with the outer periphery of the rotor, failing to ensure the hermetic sealing of combustion gas or to improve durability.
A tall partition and a cam mechanism driving it protrude upward, significantly increasing the height of the engine. Not only forward rotation torque but also reverse rotation torque is generated in the later stage of the combustion stroke, making it difficult to increase the output performance.
The rotary engine of Patent Document 5 has an oval rotor with a rotor head having a large curvature. When the engine is rotated at a higher speed, the partition cannot follow the rotation of the rotor and may jump. The operation chamber is formed on the outer periphery side of the rotor. A radial partition that partitions the operation chamber is provided on the outer periphery side of the rotor, increasing the engine size.
The prior art unidirectional rotary engine has sought a rotary engine having the operation chamber in the space on the outer periphery side of the rotor. The engine has never been successfully downsized due to lack of effectively using the rotor side space in the axial direction of the output shaft to form an annular operation chamber. It is also difficult to increase the combustion stroke to a rotation angle greater than 180 degrees of the output shaft, which sets an upper limit on the combustion performance. Furthermore, the rotor cannot be shared by multiple sets of engine.
The objects of the present invention are to provide a rotary piston type rotary engine that is advantageous to downsizing, to provide a rotary piston type combustion engine having sliding parts making area-contact for hermetic sealing, to provide a rotary piston type combustion engine effectively using the rotor side space in the axial direction of the output shaft to form an annular operation chamber, to provide a rotary piston type combustion engine having a sufficiently large combustion stroke, and to provide a rotary piston type combustion engine in which the rotor is shared by multiple engines.
The present invention provides a rotary piston type internal combustion engine comprising an output shaft, a rotor coupled to the output shaft with no relative rotation, a housing rotatably supporting the output shaft, an annular operation chamber formed by the rotor and housing, at least one pressuring/pressured member provided to the rotor for partitioning the annular operation chamber, at least one operation chamber partitioning member provided to the housing for partitioning the annular operation chamber, an intake port for introducing intake air into the annular operation chamber, an exhaust port for exhausting gas from the annular operation chamber, and a fuel supply means for supplying fuel, wherein compressed fuel-air mixture is ignited using a spark plug or compression ignition, wherein the annular operation chamber is formed by at least one of sidewall portions of the rotor in the axial direction of the output shaft and the housing, and has an entirely or mostly cylindrical inner peripheral wall and an entirely or mostly cylindrical outer peripheral wall; one of the pressuring/pressured member and operation chamber partitioning member is constituted by a reciprocating partitioning member that reciprocates in parallel to the axis of the output shaft between an advanced position where it partitions the annular operation chamber and a retracted position where it is retracted from the annular operation chamber; a biasing means for biasing the reciprocating partitioning member toward the advanced position is provided; and the other of the pressuring/pressured member and operation chamber partitioning member is constituted by an arc-shaped partitioning member having a first inclined surface for driving the reciprocating partitioning member from the advanced position to the retracted position, a forefront sliding surface continued from the first inclined surface, and a second inclined surface continued from the forefront sliding surface and allowing the reciprocating partitioning member to return from the retracted position to the advanced position.
Operation and advantages of the engine of the present invention is described hereafter.
The annular operation chamber is formed by at least one of sidewall portions of the rotor and the housing. The annular operation chamber is hermetically partitioned by at least one pressuring/pressured member provided to the rotor and by at least one operation chamber partitioning member provided to the housing. The pressuring/pressured member is capable of compressing intake air in cooperation with the operation chamber partitioning member and receiving combustion gas pressure as the rotor rotates.
As the rotor rotates, the reciprocating partitioning member moves reciprocatively between its advanced position and its retracted position while making contact with the first inclined surface, forefront sliding surface, and second inclined surface of the arc-shaped partition in sequence.
For example, when the pressuring/pressured member is constituted by the arc-shaped partitioning member and the operation chamber partitioning member is constituted by the reciprocating partitioning member, the arc-shaped partitioning member has an inner peripheral side sliding surface making area-contact with the inner peripheral surface of the annular operation chamber, an outer peripheral side sliding surface making area-contact with the outer peripheral surface of the annular operation chamber, and a forefront sliding surface making area-contact with the housing side annular wall of the annular operation chamber. The reciprocating partitioning member has a forefront sliding surface making area-contact with the rotor side annular wall. The reciprocating partitioning member does not make relative movement to the housing in the circumferential direction; which is advantageous for hermetic sealing. An engaging guide mechanism for inhibiting relative movement of the reciprocating partitioning member to the housing in the circumferential direction can be provided.
The annular operation chamber is formed by at least one sidewall portion of the rotor and the housing. Therefore, there is no member largely protruding outward from the outer periphery of the rotor, which contributes to downsizing of the internal combustion engine. Both the arc-shaped partitioning member and the reciprocating partitioning member can make area-contact with the walls of the annular operation chamber, easily assuring sealing and lubricating properties.
The annular operation chamber is formed by at least one sidewall portion of the rotor in the axial direction of the output shaft and the housing. Therefore, the annular operation chamber can have a maximized radius within the diameter of the rotor. In such a case, the radius from the output shaft to the pressuring/pressured member receiving combustion gas pressure (which corresponds to the crank radius) can be significantly greater than the crank radius of a reciprocating engine. Combustion gas pressure is converted to output (torque, horsepower) with a significantly increased efficiency, achieving an internal combustion engine having high fuel economical efficiency.
For example, when the rotor comprises one arc-shaped partitioning member and the housing comprises two reciprocating partitioning members, every one rotation of the output shaft realizes one combustion stroke, which reduces the cylinder capacity to half the cylinder capacity of a four-cycle engine, realizing a significantly downsized engine. The combustion stroke can span over a rotation angle of approximately 180 or greater of the output shaft. A prolonged combustion period and increased combustion performance can be realized. The annular operation chamber can be provided on either side of the rotor and the one rotor can be shared by two sets of internal combustion engine, advantageous to achieving a downsized, high power internal combustion engine.
On the other hand, when most part of the annular operation chamber is formed in the rotor, it is preferable that the rotor comprises the reciprocating partitioning member as the pressuring/pressured member and the housing comprises the arc-shaped partitioning member as the operation chamber partitioning member. In such a case, the same advantages as described above can be expected.
The following various structures can be applied to the present invention.
(1) The annular operation chamber can constitute an intake operation chamber, a compression operation chamber, a combustion operation chamber, and an exhaust operation chamber by means of the pressuring/pressured member and operation chamber partitioning member.
(2) The sidewall portion of the rotor is the larger-diameter sidewall portion having a radius of 0.5R or greater from the axis of the output shaft in which R is the radius of the rotor.
(3) The annular operation chamber is constituted by an annular groove recessed in the housing with an opening end facing the rotor and having a rectangular half section in a plane containing the axis of the output shaft and an annular wall of the rotor closing the opening end of the annular groove.
(4) The annular operation chamber has a rectangular half section with arc-like rounded corners in a plane containing the axis of the output shaft and is constituted by a shallow annular groove formed in the rotor and a deep annular groove formed in the housing; the shallow annular groove has a first annular wall on a plane orthogonal to the axis of the output shaft and inner and outer corner walls that are on the inner peripheral side and on the outer peripheral side of the first annular wall; and the deep annular groove has an inner cylindrical wall, an outer cylindrical wall, a second annular wall on a plane orthogonal to the axis of the output shaft, and inner and outer corner walls that are on the inner peripheral side and on the outer peripheral side of the second annular wall.
(5) An engaging guide mechanism that inhibits the reciprocating partitioning member from moving in the circumferential direction and allows the reciprocating partitioning member to move in parallel to the axis of the output shaft is provided.
(6) The biasing means is constituted by a gas spring biasing the reciprocating partitioning member toward the advanced position.
(7) The annular operation chamber is provided on either side of the rotor in the axial direction of the output shaft and these annular operation chambers each is provided with the pressuring/pressured member and the operation chamber partitioning member.
(8) The annular operation chamber has a wall parallel to a plane orthogonal to the axis of the output shaft; and the reciprocating partitioning member has on the forefront end a first sliding surface for making hermetic contact with the first inclined surface of the arc-shaped partitioning member, a forefront sliding surface for making hermetic contact with the wall of the annular operation chamber that is parallel to a plane orthogonal to the axis of the output shaft, and a second sliding surface for making hermetic contact with the second inclined surface of the arc-shaped partitioning member.
(9) The arc-shaped partitioning member has an inner peripheral side sliding surface making contact with the inner peripheral wall and an outer peripheral side sliding surface making contact with the outer peripheral wall and the inner and outer peripheral side sliding surfaces of the arc-shaped partitioning member are each provided with a seal-installation groove to which lubricating oil is supplied and one or more sealing members movably installed in the seal-installation groove.
(10) In the above (8), the reciprocating partitioning member has an inner peripheral side sliding surface and an outer peripheral side sliding surface and the inner and outer peripheral side sliding surfaces and first, forefront, and second sliding surfaces of the reciprocating partitioning member are each provided with one or more seal-installation grooves to which lubricating oil is supplied and one or more sealing members movably installed in the seal-installation groove.
(11) In the above (8), the leading end in the rotor rotation direction of the first inclined surface of the arc-shaped partitioning member is on a line orthogonal to the axis of the output shaft, the first inclined surface has a circumferential inclination progressively decreased in the radially outward direction, the trailing end in the rotor rotation direction of the second inclined surface of the arc-shaped partitioning member is on a line orthogonal to the axis of the output shaft, and the second inclined surface has a circumferential inclination progressively decreased in the radially outward direction.
(12) The pressuring/pressured member provided to the rotor is constituted by the arc-shaped partitioning member and the housing is provided with as the operation chamber partitioning member a first reciprocating partitioning member and a second reciprocating partitioning member spaced from the first reciprocating partitioning member by at least 180 degrees in the rotor rotation direction.
(13) In the above (12), an auxiliary combustion chamber is formed in a wall portion of the housing on an output shaft side than the first reciprocating partitioning member, the intake port is formed in a portion of the housing near the second reciprocating partitioning member at the leading side in the rotor rotation direction than the second reciprocating partitioning member, and the exhaust port is formed in a portion of the housing near the second reciprocating partitioning member at the trailing side in the rotor rotation direction than the second reciprocating partitioning member.
(14) In the above (13), when the pressuring/pressured member is between the intake port and the first reciprocating partitioning member, the intake operation chamber is formed between the second reciprocating partitioning member and the pressuring/pressured member and the compression operation chamber is formed between the pressuring/pressured member and the first reciprocating partitioning member in the annular operation chamber; and when the pressuring/pressured member is between the first reciprocating partitioning member and the exhaust port, the combustion operation chamber is formed between the first reciprocating partitioning member and the pressuring/pressured member and the exhaust operation chamber is formed between the pressuring/pressured member and the second reciprocating partitioning member in the annular operation chamber.
(15) In the above (14), the fuel supply means has a fuel injector for injecting fuel into the compression operation chamber.
(16) In the above (14), the fuel supply means has a fuel injector for injecting fuel into the auxiliary combustion chamber.
(17) In the above (15), the fuel supply means has a fuel injector that additionally injects fuel into the combustion operation chamber.
(18) In the above (14), an inlet passage for connecting the compression operation chamber to the auxiliary combustion chamber, an inlet passage on-off valve for opening/closing the inlet passage, an outlet passage for discharging combustion gas in the auxiliary combustion chamber into the combustion operation chamber, and an outlet passage on-off valve for opening/closing the outlet passage are provided.
(19) In the above (18), multiple valve-driving means for driving the inlet passage on-off valve and outlet passage on-off valve in synchronism with the rotation of the output shaft are provided.
(20) The operation chamber partitioning member is constituted by the reciprocating partitioning member and an auxiliary chamber is formed within the reciprocating partitioning member.
(21) The pressuring/pressured member is constituted by the reciprocating partitioning member, the housing is provided with as the operation chamber partitioning member one or a multiple number of the arc-shaped partitioning members, and an auxiliary combustion chamber is formed at least one of the arc-shaped partitioning members.
(22) The rotor is provided with as the pressuring/pressured member one of the arc-shaped partitioning member; the housing is provided with as the operation chamber partitioning member one reciprocating partitioning member; an intake port is formed in a portion of the housing at the leading side in the rotor rotation direction than the reciprocating partitioning member and an exhaust port is formed in the housing near said reciprocating partitioning member at the trailing side in the rotor rotation direction than the reciprocating partitioning member; and an intake valve for opening/closing the intake port and an exhaust valve for opening/closing the exhaust port are provided.
(23) In the above (11), the rotor is provided with as the pressuring/pressured member two of the arc-shaped partitioning members spaced from each other by approximately 180 degrees in the rotor rotation direction.
(24) In the above (12), the rotor is provided with as the pressuring/pressured member three of the arc-shaped partitioning members provided at trisected positions on the circumference.
(25) The rotor is provided with as the pressuring/pressured member four of the arc-shaped partitioning members provided at quadrisected positions on a circumference and the housing is provided with as the operation chamber partitioning member four reciprocating partitioning members provided at quadrisected positions on a circumference; the intake ports are formed in the housing near leading ends in the rotor rotation direction of the two reciprocating partitioning members spaced by 180 degrees in the circumferential direction and the exhaust ports are formed in the housing near trailing ends in the rotor rotation direction thereof.
(26) Multiple annular operation chambers having different sizes are provided on at least one sidewall portion of the rotor concentrically with radial intervals, the rotor is provided with at least one pressuring/pressured member that partitions each annular operation chamber, and the housing is provided with at least one operation chamber partitioning member that partitions each annular operation chamber.
(27) The fuel supply means has a fuel injector for injecting fuel into the auxiliary combustion chamber and fuel-air mixture in the auxiliary combustion chamber is ignited using compression ignition.
The above structures, other basic structure, and modified embodiments of the present invention and their operations and effects are described in detail using embodiments described later.
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1 output shaft
2 rotor
4 housing
5 annular operation chamber
6 arc-shaped partitioning member
7,8 first and second reciprocating partitioning members
9, 10 gas spring
11 intake port
12 exhaust port
13 auxiliary combustion chamber
15, 16 first and second on-off valves
18, 19 valve-driving mechanism
25 annular groove
25
a, 25b inner and outer peripheral walls
26 rotor annular wall
41, 43 first and second inclined surfaces
42 forefront sliding surface
58, 59 first and second sliding surfaces
The present invention relates to a rotary piston type internal combustion engine (termed “rotary engine” hereafter) comprising an output shaft, a rotor coupled to the output shaft with no relative rotation, a housing rotatably supporting the output shaft, an annular operation chamber formed by the rotor and housing, at least one pressuring/pressured member provided to the rotor for partitioning the annular operation chamber, at least one operation chamber partitioning member provided to the housing for partitioning the annular operation chamber, an intake port for introducing intake air into the annular operation chamber, an exhaust port for exhausting gas from the annular operation chamber, and a fuel supply means for supplying fuel, wherein compressed fuel-air mixture is ignited using a spark plug or compression ignition.
Particularly, the present invention has the following characteristic structures. The annular operation chamber is formed by at least one of sidewall portions of the rotor in the axial direction of the output shaft and the housing and has an entirely or mostly cylindrical inner peripheral wall and an entirely or mostly cylindrical outer peripheral wall.
One of the pressuring/pressured member and operation chamber partitioning member is constituted by a reciprocating partitioning member reciprocating in parallel to the axis of the output shaft between an advanced position where it partitions the annular operation chamber and a retracted position where it is retracted from the annular operation chamber. A biasing means for biasing the reciprocating partitioning member toward the advanced position is provided.
The other of the pressuring/pressured member and operation chamber partitioning member is constituted by an arc-shaped partitioning member having a first inclined surface that drives the reciprocating partitioning member from the advanced position to the retracted position, a forefront sliding surface continued from the first inclined surface, and a second inclined surface continued from the forefront sliding surface and allowing the reciprocating partitioning member to return from the retracted position to the advanced position.
The rotary engine of Embodiment 1 is described with reference to
As shown in
As shown in
In
As shown in
As shown in
The annular operation chamber 5 is formed by the larger-diameter sidewall portion of the sidewall of the rotor 2 having a radius of 0.5R and greater from the axis of the output shaft 1 in which R is the radius of the rotor 2 and the housing 4. This is to increase the radius (equivalent to the crank radius) from the axis of the output shaft 1 to the arc-shaped partitioning member 6 receiving combustion gas pressure as much as possible so as to generate output (torque, horsepower) as large as possible.
As shown in
The housing 4 is constituted by a circular member having a thickness approximately two times greater than the rotor 2 and a diameter greater than the rotor 2. The output shaft 1 passes through the central portion of the housing 4 and a bearing 27 is inserted between the output shaft 1 and the housing 4. The bearing 27 is supplied with lubricating oil through an oil passage formed in the wall of the housing 4. The housing 4 is positioned on the output shaft 1 by means of a stopper rings 28.
The housing 4 has an intake port 11 and an exhaust port 12. A cooling water passage 29 is formed in the housing 4. The housing 4 also has a cooling water inlet port 30 and a cooling water outlet port 31. The rotor housing 3 is fitted on the rotor 2 via a bearing 32 and a sealing member 33. The housing 4 is mounted in area-contact with the sidewalls of the rotor 2 and rotor housing 3. The rotor housing 3 and two housings 4, 4 are coupled, for example, by 11 bolts 34 (see
As shown in
Annular sealing members 38, 39, 40 for sealing between the rotor 2 and the housing 4 are installed in seal-installation grooves to which lubricating oil is supplied. The sealing members 38 to 40 are preferably made of a metal material having excellent wear proof and solid lubricating property.
As shown in
It is possible in large-size rotary engines that the first inclined surface 41 has a circumferential inclination of smaller than ⅕ and the second inclined surface 43 has a circumferential inclination of smaller than ¼.
As shown in
As shown in
As shown in
The first sliding surface 58 has the same circumferential inclination as the first inclined surface 41 (the circumferential inclination is linearly decreased in the radially outward direction). The second sliding surface 59 has the same circumferential inclination as the second inclined surface 43 (the circumferential inclination is linearly decreased in the radially outward direction).
Seal-installation grooves to which lubricating oil is supplied and sealing members 60, 61 installed in the seal-installation grooves are provided near either end of the inner and outer peripheral side sliding surfaces 50, 51. The sealing members 60, 61 are biased toward their advanced positions by lubricating oil pressure. The forefront sliding surface 53 has a leading end and a trailing end on lines orthogonal to the axis of the output shaft 1. Seal-installation grooves to which lubricating oil is supplied and sealing members 62 movably installed in the sealing-installation grooves are provided near either end of the forefront sliding surface 53. The sealing members 62 are biased toward their advanced positions by lubricating oil pressure. Sealing members 63, 64 are installed in seal-installation grooves formed in the first and second sliding surfaces 58, 59 and to which lubricating oil is supplied. The sealing members 63, 64 are biased toward their advanced positions by lubricating oil pressure.
The first reciprocating partitioning member 7 has an oil passage (not shown) in the wall, to which lubricating oil is supplied from an oil passage (not shown) in the wall of the housing 4. Then, the lubricating oil is supplied to the seal-installation grooves. A structure for preventing the sealing members 60 to 64 from coming off the seal-installation grooves or a structure for biasing the sealing members 60 to 64 using plate springs installed in the seal-installation grooves can be utilized as appropriate.
As shown in
The first gas spring 9 for biasing the first reciprocating partitioning member 7 toward its advanced position is described hereafter. As shown in
In order to reduce the weight of the first reciprocating partitioning member 7 as much as possible, the first reciprocating partitioning member 7 has a rectangular hole 66 formed from the opposite end to the rotor 2. The first gas spring 9 has a case 67 fixed to the housing 4, a plenum chamber 68 within the case 67, a guide case 69 formed integrally with the case 67 and partially and relatively slidably inserted in the rectangular hole 66, and two rods 71 hermetically and slidably installed in two rod holes 70 of the guide case 69.
The plenum chamber 68 is filled with, for example, nitrogen gas pressurized to 4.0 to 7.0 MPa. The two rods 71 receive the nitrogen gas pressure in the plenum chamber 68, whereby their tips abut against the bottom wall of the rectangular hole 66 and strongly bias the first reciprocating partitioning member 7 toward its advanced position. The first gas spring 9 is used to bias the first reciprocating partitioning member 7 toward its advanced position against pushing force (a force parallel to the axis of the output shaft 1) applied to the first reciprocating partitioning member 7 by fuel-air mixture gas pressure or combustion gas pressure. Therefore, the nitrogen gas pressure is properly determined based on the pushing force and the diameter and number of the rods 71. The structure and shape of the plenum chamber 68 is not restricted to what is shown in the figure. However, it is desirable that the plenum chamber 68 has a capacity as large as possible so that nitrogen gas pressure fluctuation is minimized while the two rods 71 reciprocate. The case 67 is constituted to allow the first reciprocating partitioning member 7 to be retracted to its retracted position shown by the broken lines in
The rectangular hole 66 can be shallower than shown in the figure or even omitted so that one or multiple rods 71 abut against the end of the first reciprocating partitioning member 7. Alternatively, gas spring pressure can directly be applied to the first reciprocating partitioning member 7. In place of the first gas spring 9, a compression spring or a hydraulic cylinder coupled to an accumulator can be used to bias the first reciprocating partitioning member 7 toward its advanced position. Further alternatively, a cam mechanism in synchronism with the output shaft 1 can be used to reciprocate the first reciprocating partitioning member 7.
As shown in
The intake port 11, exhaust port 12, intake operation chamber, compression operation chamber, combustion operation chamber, and exhaust operation chamber are described hereafter. As shown in
As shown in
As shown in
The auxiliary combustion chamber 13 and the surrounding structure is described hereafter. As shown in
A first on-off valve 15 for opening/closing the inlet passage 91 at the downstream end and a second on-off valve 16 for opening/closing the outlet passage 92 at the upstream end. The inlet passage 91 is formed so as to have a minimized capacity. The inlet passage 91 has at the upstream end a suction port 91a that is open to the annular operation chamber 5 on the inner peripheral wall 25a near the trailing end of the first reciprocating partitioning member 7. Following the suction port 91a, the inlet passage 91 has a curved portion through the wall, which is open to the auxiliary combustion chamber 13 at the downstream end, where it is closed/opened by the first on-off valve 15. The first on-off valve 15 of this embodiment is a poppet valve opened inward to the auxiliary combustion chamber 13.
The outlet passage 92 is open to the auxiliary combustion chamber 13 at the upstream end, where it is closed/opened by the second on-off valve 16. Following the upstream end opening, the outlet passage 92 has a curved portion, which ends with a blow-off port 92a that is open to the annular operation chamber 5 on the inner peripheral wall 25a near the leading end of the first reciprocating partitioning member 7. The second on-off valve 16 of this embodiment is a poppet valve opened outward from the auxiliary combustion chamber 13. However, the second on-off valve 16 can be a poppet valve opened inward to the auxiliary combustion chamber 13 as is the first on-off valve 15. The first and second on-off valves 15, 16 are given by way of example and various valve structures can be used.
Valve-driving mechanisms 18, 19 for driving the first and second on-off valves 15, 16 are described hereafter. As shown in
For example, a shaft motor 105 capable of high speed operation is provided as an actuator for driving the valve shaft 15a. The shaft motor 105 has an output member 105a coupled to the valve shaft 15a. The first on-off valve 15 is opened/closed by the shaft motor 105 in synchronism with the rotation of the output shaft 1. Similarly, for example, a shaft motor 106 capable of high speed operation is provided as an actuator for driving the valve shaft 16a. The shaft motor 106 has an output member 106a coupled to the valve shaft 16a. The second on-off valve 16 is opened/closed by the shaft motor 106 in synchronism with the rotation of the output shaft 1. The two shaft motors 105 and 106 are controlled by a control unit (not shown) for controlling the engine.
The above valve-driving mechanisms 18, 19 are given by way of example and various valve-driving mechanisms can be used.
If the shape of the auxiliary chamber 13 allows, the valve shafts 15a, 16a can be placed in parallel to the axis of the output shaft 1. In such a case, the valve shafts 15a, 16b can directly be driven by cam members provided to the output shaft 1. Alternatively, the first and second on-off valves 15a, 16b can be driven by first and second cam members driven by two cam shafts linked to the output shaft 1. Further alternatively, the first and second on-off valves 15, 16 can be driven by first and second cam members driven by two electric motors rotating in synchronism with the output shaft 1. Further alternatively, the first and second on-off valves 15, 16 can be driven individually directly by two solenoid actuators.
Actuations of the above described rotary engine E are described hereafter.
The figures show the arc-shaped partitioning member 6, first and second reciprocating partitioning members 7, 8, suction port 91a, blow-off port 92a, intake port 11, and exhaust port 12. The compression stroke end timing shown in
The first on-off valve 15 is closed at the moment of the compression upper dead point shown in
As seen from the actuations shown in
Operation and advantages of the rotary engine E is described hereafter.
The inner peripheral side sliding surface 6a of the arc-shaped partitioning member 6 makes hermetic area-contact with the inner peripheral wall 25a of the annular operation chamber 5, the outer peripheral side sliding surface 6b makes hermetic area-contact with the outer peripheral wall 25b of the annular operation chamber 5, and the forefront sliding surface 42 makes hermetic area-contact with the housing side annular wall 25c of the annular operation chamber 5. Therefore, the arc-shaped partitioning member 6 transversely and hermetically partitions the annular operation chamber 5.
The first and second reciprocating partitioning members 7, 8 hermetically partition the annular operation chamber 5 when they are at their advanced positions. When the arc-shaped partitioning member 6 rotates with the rotor 2, the first and second reciprocating partitioning members 7, 8 make hermetic contact with the first inclined surface 41, forefront sliding surface 42, and second inclined surface 43 of the arch-shaped partitioning member 6 in sequence and move from their advanced positions to their retracted positions. Then, they return to their advanced positions after the arc-shaped partitioning member 6 passes them.
The forefront sliding surfaces 53 of the first and second reciprocating partitioning members 7, 8 make hermetic area-contact with the part of the annular wall 26 of the rotor 2 that is on a plane orthogonal to the axis. The inner peripheral side sliding surfaces 50 of the first and second reciprocal partitioning members 7, 8 make hermetic area-contact with the inner peripheral wall 25a of the annular operation chamber 5 and the outer peripheral side sliding surfaces 51 make hermetic area-contact with the outer peripheral wall 25b. Consequently, the first and second reciprocating partitioning members 7, 8 hermetically and transversely partition the annular operation chamber 5. The first and second reciprocating partitioning members 7, 8 do not make relative movement to the housing 4 in the rotation direction, which is advantageous for hermetic sealing. A mechanism for inhibiting relative movement of the first and second reciprocating partitioning members 7, 8 to the housing 4 in the rotation direction can be provided (see an engaging guide mechanism 110, 110A described later).
In the rotary engines E1 and E2, the annular operation chamber 5 is formed by the larger-diameter portion of at least one of sidewall portions of the rotor 2 having a radius of 0.5R and larger (R is the radius of the rotor 2) and the housing 4. In this way, the side space of the rotor 3 in the axial direction is effectively used to form the annular operation chamber 5, eliminating a member largely protruding outward from the outer periphery of the rotor 2 and reducing the total height and width of the engine. The arc-shaped partitioning member 6 and first and second reciprocating partitioning members 7, 8 all make hermetic area-contact with the walls of the annular operation chamber 5, which is advantageous for ensuring sealing and lubricating properties and durability.
The annular operation chamber 5 faces the larger-diameter portion of the rotor 2. Therefore, the rotation radius from the axis of the output shaft 1 to the pressuring/pressured member 6 receiving the combustion gas pressure (which corresponds to the crank radius) can be significantly larger than the reciprocating engine crank radius of the same cylinder capacity. Furthermore, the combustion gas pressure is converted to output torque via the above larger rotation radius, thereby significantly improving the conversion efficiency from combustion gas pressure to output (torque, horsepower) and achieving an internal combustion engine having high fuel economical efficiency.
The rotor engine E1 has one arc-shaped partitioning member 6 on one side of the rotor 2 and the first and second reciprocating partitioning members 7, 8 on the housing 4. One combustion stroke is realized by one rotation of the output shaft 1 and, therefore, the cylinder capacity can be reduced to half the cylinder capacity of a four-cycle engine of the same output power, thereby downsizing the engine. For example, when the annular operation chamber 5 has an inner radius of 17 cm, an outer radius of 23 cm, and a thickness of 4 cm in the axial direction, and the intake operation chamber 80 has an arc length of 105 degrees in the circumferential direction, the intake operation chamber 80 has a capacity of approximately 750 cc, which corresponds to a four-cycle engine having a cylinder capacity of 1500 cc. Furthermore, it corresponds to a four-cycle engine having a cylinder capacity of 3000 cc since two sets of the annular operation chamber 5 are provided on either side of the rotor 2. However, because of compressed fuel-air mixture remaining in the inlet passage 91, the inner and outer radiuses may be approximately 18 cm and 24 cm, respectively, in practice.
In addition, the combustion stroke can span 180 to 200 degrees or even larger of the output shaft. The combustion stroke can be made larger than that of a four-cycle engine for improved combustion performance. The annular operation chamber 5 is formed on either side of the rotor 2 and the rotor 2 is shared by two sets of engine E1 and E2. This is advantageous for producing a downsized, but higher output engine and for lower engine rotation speeds.
A partially modified embodiment of the above rotary engine E is described hereafter.
As shown in
The engaging protrusions 111, 112 protrude from the inner and outer peripheral side sliding surfaces 50, 51 of the first reciprocating partitioning member 7 at the center in the width direction, respectively, and are parallel to the axis of the output shaft 1. The engaging grooves 111a, 112a are recessed in the inner and outer peripheral walls 25a, 25b of the annular operation chamber 5, respectively. Gas pressure applied to the first reciprocating partitioning member 7A in the circumferential direction is sustained by the engaging guide mechanism 110, whereby the load on the first reciprocating partitioning member 7A is alleviated and elastic deformation of the first reciprocating partitioning member 7A in the circumferential direction can be prevented. Consequently, the first reciprocating partitioning member 7A can smoothly reciprocate and be reduced in size. Here, the engaging protrusion and engaging groove on one side (on the inner or outer side) can be eliminated. Key members can be used in place of the engaging protrusions 111, 112.
An engaging guide mechanism 110A shown in
As in the above embodiment, when the annular operation chamber 5A has a rectangular half-section, the combustibility of fuel-air mixture may be lower in the corners of the annular operation chamber 5A. Then, as shown in
The shallow groove 115 has a first annular wall 116 on a plane orthogonal to the axis of the output shaft 1 and inner and outer corner walls 117, 118 that is on the inner peripheral side and on the outer peripheral side of the first annular wall 116. The deep groove 120 has an inner cylindrical wall 121, an outer cylindrical wall 122, a second annular wall 123 on a plane orthogonal to the axis of the output shaft 1, and inner and outer corner walls 124, 125 that are on the inner peripheral side and on the outer peripheral side of the second annular wall 123. As shown in
The solid line 126 represents the border between the rotor 2A and the housing 4A and the broken line 127 represents the ends of the rounded corner walls 124, 125. The inner peripheral wall of the annular operation chamber 5A is mostly cylindrical and the outer peripheral wall is mostly cylindrical. Instead of using the first and second contact surfaces 58A, 59A having increased widths, shallow recesses making hermetic contact with the forefront part of the first reciprocating partitioning member 7C can be formed in the first and second inclined surfaces 41, 43.
As shown in
A rotor 2B has an annular groove 140 that is a similar groove to the annular groove 25 constituting the annular operating chamber 5 and open on the side to a housing 4B. The rotor 2B is provided with a reciprocating partitioning member 7R as the pressuring/pressured member. As shown in
A rotary valve 143 for opening/closing the inlet passage 141 and a rotary valve 144 for opening/closing the outlet passage 142 are rotatably installed in the arc-shaped partitioning member 6A. The rotary valves 143, 144 are each rotated by 90 degrees by an actuator (not shown) to open/close the inlet and outlet passages 141, 142, respectively, in synchronism with the rotation of the output shaft 1. Here, the spark plug 17 for igniting compressed fuel-air mixture in the auxiliary combustion chamber 13B is also provided. The inlet passage 141 is flattened and small in length, thereby having a smaller capacity, which is suitable for small-size rotary engines. The inlet and outlet passages 141, 142 can be opened/closed by shifting the rotary valves 143, 144 in their axial direction. A case or housing member for covering the exterior of the rotor 2B can be provided where necessary.
As shown in
A flattened inlet passage 153 for introducing compressed fuel-air mixture from the compression operation chamber 81 into the auxiliary combustion chamber 13C is formed. A rotary valve 154 for opening/closing the inlet passage 153 is installed in the first partitioning member 151. The rotary valve 154 is rotated by 90 degrees by an actuator (not shown) provided to the first partitioning member 151 to open/close the inlet passage 153. The first partitioning member 151 is also provided with the spark plug 17 for igniting fuel-air mixture in the auxiliary combustion chamber 13C and an annular sealing member 155 for sealing the outer periphery of the opening of the auxiliary combustion chamber 13C.
The first partitioning member 151 is biased toward its advanced position by a gas spring or a metal spring (not shown). The second partitioning member 152 reciprocates in synchronism with the rotation of the output shaft 1 by means of a cam mechanism (not shown) linked to the output shaft 1.
With the first reciprocating partitioning member 150, the inlet passage 153 can have a significantly small capacity and combustion gas is ejected into the combustion operation chamber from the auxiliary combustion chamber 13C, which is suitable for small-size engines.
The rotary valves can be eliminated. In such a case, the inlet passage 153 can be opened/closed by a third partitioning member similar to the second partitioning member 152, the third partitioning member being provided on the trailing end side of the first partitioning member 151 and reciprocated by a cam mechanism.
In a rotary engine EA shown in
In the rotary engine EA, the intake and exhaust valves are properly opened/closed in synchronism with the rotation of the output shaft 1, whereby every four rotations of the output shaft 1 result in two combustion strokes. When two sets of engine are provided on either side of the rotor, every four rotations of the output shaft 1 result in four combustion strokes. The combustion period spans over a rotation angle of 360 degrees of the output shaft 1. This sufficient combustion period significantly improves combustion performance.
A rotary engine EB shown in
In the engine EB, two sets of intake and exhaust valves are properly opened/closed in synchronism with the rotation of the output shaft 1, whereby every two rotations of the output shaft 1 result in four combustion strokes. When two sets of engine are provided on either side of the rotor, every two rotations of the output shaft 1 result in eight combustion strokes.
In a rotary engine EC shown in
A rotary engine ED shown in
The rotor comprises as the pressuring/pressured member three arc-shaped partitioning members 6, 6, 6 at trisected positions on the circumference. In the engine ED, three ignitions occur in every one rotation of the rotor. A combustion stroke occurs for every 120-degrees rotation of the output shaft 1. When two sets of engine are provided on either side of the rotor, a combustion stroke occurs for every 60 degree-rotation of the output shaft 1. Therefore, the engine can be reduced in size, have a margin in the cylinder capacity, and be driven at lower speeds, thereby leading to improved combustion performance.
A rotary engine EE shown in
In the engine EE, the two auxiliary combustion chambers are ignited for two combustion strokes in every 90-degree rotation of the output shaft 1. Therefore, every one rotation of the output shaft 1 results in eight combustion strokes. Consequently, the engine can be reduced in size.
As indicated by the broken lines, an annular operation chamber 5A can be formed inside the annular operation chamber 5. The annular operation chamber 5A can be provided with multiple reciprocating partitioning members, multiple arc-shaped partitioning members, multiple auxiliary combustion chambers, and two sets of intake and exhaust ports as with the outer annular operation chamber 5. In this way, another set of engine is additionally constituted for effective use of space in the rotor and housing. Two sets of intake and exhaust ports for the annular operation chamber 5A can be formed in the right wall of the housing 4G. In this way, with two sets of engine being provided on one side of the rotor, the engine can be further reduced in size. Furthermore, four sets of engine can be provided on either side of the rotor. Therefore, the engine EE is useful for large-size marine engines.
The above rotary engines are described as ignition engine by way of example in which fuel-air mixture is ignited by a spark plug. The rotary engine of the present invention is applicable to diesel engines in which fuel is injected into compressed air in an auxiliary combustion chamber and ignited using compression ignition. However, in the case of diesel engines, the compression ratio should be increased to approximately 22.
The rotary engine of the present invention can be used in engines using various fuels such as heavy oil, diesel oil, gasoline, ethanol, LPG, natural gas, and hydrogen gas; engines in various applications such as vehicles, construction machinery, agricultural machinery, various industrial machinery, and various cylinder capacity marine engines; and small to large cylinder capacity engines.
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/JP2006/309315 | 5/9/2006 | WO | 00 | 6/6/2007 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2007/080660 | 7/19/2007 | WO | A |
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| 20090194065 A1 | Aug 2009 | US |
