engine

Abstract

Provided is an engine in which it is possible to optimize valves in the vicinity of cylinder chambers and an advancing and retracting mechanism of the valves.　An engine 10 comprises cylinder chambers 12, intake valves 18, exhaust valves 19, and an advancing and retracting mechanism 20 for advancing and retracting the intake valves 18 and the exhaust valves 19. The advancing and retracting mechanism 20 has a camshaft 21, exhaust cams 22, intake cams 23, pushrods 24, and rocker arms 25. The intake cams 23 are fixed to the camshaft 21 and are configured to advance and retract the intake valves 18. The exhaust cams 22 are configured to advance and retract the pushrods 24. The rocker arms 25 are rotated by the pushrods 24 and are configured to advance and retract the exhaust valves 19.

Description

Technical Field

[0001] The present invention relates to an engine, and more particularly to an opposed-piston engine.

Background Art

[0002] Conventionally, as shown in Patent Document 1 and Patent Document 2, in an opposed-piston engine, a piston having piston heads facing each other generally performs a linear motion in a horizontally arranged cylinder. In this cylinder, the region where the piston heads face each other functions as a combustion chamber, and the mixture of fuel and air causes a spark explosion, causing the piston to operate and supplying power to an external actuator such as a generator.

[0003] However, in the engines described in such patent documents, it is difficult to increase the compression ratio due to the small combustion chamber volume, and there are also problems with heat insulation of the combustion chamber. In addition, the intake and exhaust valves of a conventional opposed-piston engine are directly opened into the combustion chamber, which has the drawback of increasing the volume of the combustion chamber.

[0004] In order to solve such problems, an engine described in Patent Document 3 was invented. In the engine described in Patent Document 3, independent left and right pistons are arranged facing each other in a horizontal cylinder. In addition, one combustion chamber is formed to communicate with the outside of the horizontal cylinder between the left and right piston heads. Further, in the engine described in Patent Document 3, an extension portion extending laterally from the combustion chamber is formed. A spark plug is provided in the extension portion.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Patent Document 3

[0006] However, the opposed-piston engine described in the aforementioned patent document had room for improvement in terms of optimizing the valve reciprocating mechanism that controls the movement of the valves.

[0007] Specifically, in the opposed-piston engine described in Patent Document 3, when the direction of piston reciprocation is considered to be the front-rear direction, the intake valve and exhaust valve were arranged to be concentrated in front of or behind the extension. Furthermore, the reciprocating mechanism for the intake valve and exhaust valve was also arranged near the intake valve and exhaust valve. Therefore, there was a problem of the mechanical configuration around the extension becoming complicated.

[0008] Furthermore, in opposed-piston engines, if multiple cylinder chambers are arranged to increase power output, the aforementioned issues become apparent.

[0009] This invention has been made in view of these problems, and the object of this invention is to provide an engine that can optimize the valve and its reciprocating mechanism in the vicinity of the cylinder chamber. [Means for solving the problem]

[0010] The engine of the present invention comprises a cylinder chamber, an intake valve, an exhaust valve, and a reciprocating mechanism for moving the intake valve and the exhaust valve forward and backward, wherein the reciprocating mechanism includes a camshaft, a first cam, a second cam, a push rod, and a rocker arm, the first cam being fixed to the camshaft and configured to move either the intake valve or the exhaust valve forward and backward, the second cam being separate from the first cam and configured to move the push rod forward and backward, and the rocker arm being rotated by the push rod and configured to move either the intake valve or the exhaust valve forward and backward.

[0011] Furthermore, the engine of the present invention is characterized in that the first cam moves the plurality of intake valves forward and backward, and the second cam moves the exhaust valve forward and backward via the push rod.

[0012] Furthermore, the engine of the present invention is characterized in that, when the axial direction of the cylinder chamber is the front-rear direction, pistons are arranged to move back and forth opposite each other along the front-rear direction, and there is an extension space extending laterally from the middle part of the cylinder chamber in the front-rear direction, the intake valve is provided so as to be able to move back and forth in relation to the extension space from the front side, and the exhaust valve is provided so as to be able to move back and forth in relation to the extension space from the rear side.

[0013] Furthermore, in the engine of the present invention, the cylinder chamber has a first cylinder chamber and a second cylinder chamber adjacent to the first cylinder chamber, and a first piston and a second piston are housed inside the first cylinder chamber so as to reciprocate, and a third piston and a fourth piston are housed inside the second cylinder chamber so as to reciprocate, and has a first extension space extending laterally from the middle part of the first cylinder chamber in the front-rear direction, and a second extension space extending laterally from the middle part of the second cylinder chamber in the front-rear direction The invention features two extension spaces, the intake valve comprising a first intake valve and a second intake valve, the exhaust valve comprising a first exhaust valve and a second exhaust valve, the first intake valve being provided to be able to move back and forth relative to the first extension space from the front, the first exhaust valve being provided to be able to move back and forth relative to the first extension space from the rear, the second intake valve being provided to be able to move back and forth relative to the second extension space from the front, and the second exhaust valve being provided to be able to move back and forth relative to the second extension space from the rear.

[0014] Furthermore, in the engine of the present invention, the number of intake valves is greater than the number of exhaust valves, and the spark plugs are arranged to be exposed on the side of the extension space where the exhaust valves are provided. [Effects of the Invention]

[0015] The engine of the present invention comprises a cylinder chamber, an intake valve, an exhaust valve, and a reciprocating mechanism for moving the intake valve and the exhaust valve forward and backward, wherein the reciprocating mechanism includes a camshaft, a first cam, a second cam, a push rod, and a rocker arm, the first cam being fixed to the camshaft and configured to move either the intake valve or the exhaust valve forward and backward, the second cam being separate from the first cam and configured to move the push rod forward and backward, and the rocker arm being rotated by the push rod and configured to move either the intake valve or the exhaust valve forward and backward. According to the engine of the present invention, by moving either the intake valve or the exhaust valve forward and backward with the first cam and moving either the intake valve or the exhaust valve backward and with the push rod, the reciprocating mechanism can be arranged near the cylinder even when there are strict geometric constraints near the cylinder. Furthermore, by using pushrods, the number of camshafts can be reduced, thereby simplifying the engine's configuration.

[0016] Furthermore, in the engine of the present invention, the first cam moves the plurality of intake valves forward and backward, and the second cam moves the exhaust valve forward and backward via the push rod. According to the engine of the present invention, the forward and backward mechanism for moving the intake valves and exhaust valves forward and backward can be integrated into a limited space.

[0017] Furthermore, in the engine of the present invention, the cylinder chamber has a piston arranged to reciprocate when the axial direction of the cylinder chamber is the front-rear direction, and the piston is arranged to face the cylinder chamber in the front-rear direction. The cylinder chamber has an extension space that extends laterally from the middle of the cylinder chamber in the front-rear direction, the intake valve is provided so as to be able to move back and forth in relation to the extension space from the front side, and the exhaust valve is provided so as to be able to move back and forth in relation to the extension space from the rear side. According to the engine of the present invention, the intake valve and exhaust valve are arranged close together because the extension space is sandwiched between them, but since the intake valve or exhaust valve is moved back and forth via a push rod, the configuration around the extension space can be simplified.

[0018] Furthermore, in the engine of the present invention, the cylinder chamber has a first cylinder chamber and a second cylinder chamber adjacent to the first cylinder chamber, and a first piston and a second piston are housed inside the first cylinder chamber so as to reciprocate, and a third piston and a fourth piston are housed inside the second cylinder chamber so as to reciprocate, and has a first extension space extending laterally from the middle part of the first cylinder chamber in the front-rear direction, and a second extension space extending laterally from the middle part of the second cylinder chamber in the front-rear direction The engine of the present invention has two extension spaces, the intake valve comprises a first intake valve and a second intake valve, the exhaust valve comprises a first exhaust valve and a second exhaust valve, the first intake valve is provided so as to be able to move back and forth relative to the first extension space from the front side, the first exhaust valve is provided so as to be able to move back and forth relative to the first extension space from the rear side, the second intake valve is provided so as to be able to move back and forth relative to the second extension space from the front side, and the second exhaust valve is provided so as to be able to move back and forth relative to the second extension space from the rear side.According to the engine of the present invention, even when multiple cylinder chambers are adjacent to each other and a large number of intake valves and exhaust valves are provided, the overall configuration of the engine can be simplified by optimizing the configuration of the camshaft and pushrods.

[0019] In the engine of the present invention, the number of intake valves is larger than the number of exhaust valves, and the spark plug is disposed so as to be exposed on the side of the extended space where the exhaust valve is provided. According to the engine of the present invention, since the spark plug is exposed in the extended space from the side of the exhaust valve with a small number, the space around the extended space can be effectively used.

Brief Description of Drawings

[0020] [Figure 1] It is a perspective view showing an engine according to an embodiment of the present invention. [Figure 2A] It is a view showing an engine according to an embodiment of the present invention, and is a perspective view showing a first engine block. [Figure 2B] It is a view showing an engine according to an embodiment of the present invention, and is a perspective view showing a second engine block. [Figure 3A] It is a view showing an engine according to an embodiment of the present invention, and is a view showing a first contact surface of a first engine block. [Figure 3B] It is a view showing an engine according to an embodiment of the present invention, and is a view showing a second contact surface of a second engine block. [Figure 4] It is a view showing an engine according to an embodiment of the present invention, and is a perspective view showing an engine part and the like. [Figure 5] It is a view showing an engine according to an embodiment of the present invention, and is a perspective view showing valves and a reciprocating mechanism. [Figure 6] It is a view showing an engine according to an embodiment of the present invention, and is an exploded perspective view showing valves and a reciprocating mechanism. [Figure 7A] It is a view showing an engine according to an embodiment of the present invention, and is a perspective view of a second cylinder chamber and a second extended space and the like as seen from the rear. [Figure 7B] It is a view showing an engine according to an embodiment of the present invention, and is a perspective view of a second cylinder chamber and a second extended space and the like as seen from the front. [Figure 8]This figure shows an engine according to an embodiment of the present invention, and is a cross-sectional view showing the wall portion of the engine block that forms the cylinder chamber and extension space. [Modes for carrying out the invention]

[0021] Hereinafter, an engine 10 according to an embodiment of the present invention will be described in detail with reference to the drawings. In the following description, the front-rear direction refers to the direction in which the piston, described later, reciprocates along the axial direction of the cylinder chamber, described later. The left-right direction refers to the direction in which the cylinder spaces, described later, are arranged. In the following description, the same reference numerals are generally used for the same components, and repeated descriptions are omitted. Furthermore, in this embodiment, the configuration described in the claims will be mainly illustrated and described. Therefore, parts of the engine 10 other than the said configuration, such as the crankshaft rotation synchronization mechanism, lubrication oil supply mechanism, fuel supply mechanism, electrical components, etc., are not shown.

[0022] Figure 1 is a perspective view showing engine 10.

[0023] Engine 10 is an opposed-piston type engine having multiple pistons arranged opposite each other. The internal configuration and operation of engine 10 will be described later with reference to Figures 2A and later.

[0024] Engine 10 is configured to operate using gasoline, diesel fuel, hydrogen, etc. Engine 10 can be used as a power source for various devices. Engine 10 is used as a power source for vehicles, generators, water heaters, flying devices, drones, series hybrid drones, parallel hybrid drones, etc. A series hybrid drone is a drone in which engine 10 drives a generator, the electricity generated from the generator rotates a motor, the motor rotates a rotor, and the lift generated by the rotation of the rotor makes the drone float in the air. A parallel hybrid drone is a drone in which engine 10 mechanically rotates a main rotor, and the lift generated by the rotation of the main rotor makes the drone float. The engine 10 of this embodiment is an opposed-piston type engine, and because it is lightweight and has low vibration, it is particularly suitable as a power source for series hybrid drones, parallel hybrid drones, etc.

[0025] Specifically, the engine 10 comprises a cylinder chamber 12, an intake valve 18, an exhaust valve 19, and a reciprocating mechanism 20. Each of these components constituting the engine 10 is housed in the engine block 11. The configuration of the cylinder chamber 12 will be explained with reference to Figure 4, etc. The intake valve 18, exhaust valve 19, and reciprocating mechanism 20 will be explained with reference to Figure 5, etc.

[0026] The engine 10 also has an engine block 11, which is the main body. The engine block 11 is made of, for example, a cast aluminum alloy. The engine block 11 consists of a first engine block 111, a second engine block 112, a third engine block 113, and a fourth engine block 114. These parts are fastened together by fastening members such as stud bolts (not shown).

[0027] A third crankshaft 163 and a fourth crankshaft 173 are routed out from the right side of the engine 10. Rotational power can be extracted externally from the third crankshaft 163 and the fourth crankshaft 173. In addition, a shaft can be routed out from the left side of the engine 10, and power can also be extracted externally from this shaft.

[0028] Furthermore, a second spark plug 262 is mounted on the right side of the engine block 11. Similarly, a first spark plug 261 (not shown) is mounted on the left side of the engine block 11. In addition, a belt 32 and a driven gear 30 for driving the forward / backward mechanism 20, which will be described later, are arranged on the left side of the engine block 11. These components will be described later with reference to Figures 5 and later.

[0029] Figure 2A is a perspective view showing the first engine block 111.

[0030] Referring to Figure 2A, the rearward-facing surface of the first engine block 111 is designated as the first contact surface 40. The first contact surface 40 is a flat surface and contacts the second contact surface 41 of the second engine block 112, which will be described later.

[0031] The first engine block 111 has a first cylinder chamber front portion 1211 and a second cylinder chamber front portion 1221 formed forward from the first contact surface 40. The first cylinder chamber front portion 1211 and the second cylinder chamber front portion 1221 are adjacent to each other along the left-right direction. The first cylinder chamber front portion 1211 is a substantially cylindrical space and forms the front portion of the first cylinder chamber 121, which will be described later. The second cylinder chamber front portion 1221 is a substantially cylindrical space and forms the front portion of the second cylinder chamber 122, which will be described later.

[0032] The first extension space front portion 3311 is a portion in which the first contact surface 40 is recessed toward the front, and is continuous with the upper end of the first cylinder chamber front portion 1211. The first extension space front portion 3311 constitutes the first extension space 331, which will be described later.

[0033] The front portion 3321 of the second extension space is a part in which the first contact surface 40 is recessed toward the front, and is continuous with the upper end of the front portion 1221 of the second cylinder chamber. The front portion 3321 of the second extension space constitutes the second extension space 332, which will be described later.

[0034] Referring to Figure 2B, the forward-facing surface of the second engine block 112 is designated as the second contact surface 41. The second contact surface 41 is a flat surface and contacts the first contact surface 40 of the first engine block 111, as described above.

[0035] The second engine block 112 has a first cylinder chamber rear portion 1212 and a second cylinder chamber rear portion 1222 formed rearward from the second contact surface 41. The first cylinder chamber rear portion 1212 and the second cylinder chamber rear portion 1222 are adjacent to each other along the left-right direction. The first cylinder chamber rear portion 1212 is a substantially cylindrical space and forms the rear portion of the first cylinder chamber 121, which will be described later. The second cylinder chamber rear portion 1222 is a substantially cylindrical space and forms the rear portion of the second cylinder chamber 122, which will be described later.

[0036] The rear portion 3312 of the first extension space is a part in which the second contact surface 41 is recessed toward the rear, and is continuous with the upper end of the rear portion 1212 of the first cylinder chamber. The rear portion 3312 of the first extension space, together with the front portion 3311 of the first extension space described above, constitutes the first extension space 331, which will be described later.

[0037] The rear portion 3322 of the second extension space is a portion in which the second contact surface 41 is recessed toward the rear, and is continuous with the upper end of the rear portion 1222 of the second cylinder chamber. The rear portion 3322 of the second extension space, together with the front portion 3321 of the second extension space described above, constitutes the second extension space 332, which will be described later.

[0038] Figure 3A shows the first contact surface 40 of the first engine block 111. An intake valve mounting hole 35 is formed in the first contact surface 40. The intake valve mounting hole 35 has a first intake valve mounting hole 351 and a second intake valve mounting hole 352.

[0039] Two first intake valve mounting holes 351 are formed inside the front portion 3311 of the first extension space. The first intake valve mounting holes 351 are through holes that penetrate the wall portion of the first engine block 111 in a circular manner in the front-rear direction. A first intake valve 181, which will be described later, is disposed in each of the first intake valve mounting holes 351.

[0040] Two second intake valve mounting holes 352 are formed inside the front portion 3321 of the second extension space. The second intake valve mounting holes 352 are through holes that penetrate the wall formed inside the first engine block 111 in a circular shape. A second intake valve 182, which will be described later, is disposed in each of the second intake valve mounting holes 352.

[0041] Figure 3B shows the second contact surface 41 of the second engine block 112. The second contact surface 41 has exhaust valve mounting holes 36 and spark plug mounting holes 37. The exhaust valve mounting holes 36 have a first exhaust valve mounting hole 361 and a second exhaust valve mounting hole 362. The spark plug mounting holes 37 have a first spark plug mounting hole 371 and a second spark plug mounting hole 372.

[0042] The first exhaust valve mounting hole 361 is a hole formed in the rear portion 3312 of the first extension space. The first exhaust valve mounting hole 361 penetrates the wall formed inside the second engine block 112 in a circular shape. The first exhaust valve 191, which will be described later, is installed in the first exhaust valve mounting hole 361.

[0043] The first plug mounting hole 371 is a through hole formed inside the rear portion 3312 of the first extension space. The first plug mounting hole 371 is a through hole that penetrates the left side portion of the second engine block 112. That is, the front end of the first plug mounting hole 371 opens into the rear portion 3312 of the first extension space. The rear end of the first plug mounting hole 371 opens to the outside from the left side portion of the second engine block 112. The front end of the first spark plug 261, which will be described later, is inserted into the first plug mounting hole 371.

[0044] The second exhaust valve mounting hole 362 is a hole formed in the rear portion 3322 of the second extension space. The second exhaust valve mounting hole 362 penetrates the wall formed inside the second engine block 112 in a circular shape. The second exhaust valve 192, which will be described later, is installed in the second exhaust valve mounting hole 362.

[0045] The second plug mounting hole 372 is a through hole formed inside the rear portion 3322 of the second extension space. The second plug mounting hole 372 is a through hole that penetrates the right side portion of the second engine block 112. That is, the front end of the second plug mounting hole 372 opens into the rear portion 3322 of the second extension space. The rear end of the second plug mounting hole 372 opens to the outside from the right side portion of the second engine block 112. The front end of the second spark plug 262, which will be described later, is inserted into the second plug mounting hole 372.

[0046] Figure 4 is a perspective view of the engine section 13, which is housed in the aforementioned engine block 11, as seen from the front and above.

[0047] The engine section 13 includes a first engine section 14, a second engine section 15, a third engine section 16, and a fourth engine section 17. The first engine section 14 and the second engine section 15 constitute one opposing engine section. The third engine section 16 and the fourth engine section 17 also constitute one opposing engine section. By having multiple opposing engine sections in the engine 10, it is possible to increase power output while ensuring the lightweight and low vibration of the engine 10.

[0048] The cylinder chamber 12 comprises a first cylinder chamber 121 and a second cylinder chamber 122 adjacent to the first cylinder chamber 121. The first cylinder chamber 121 and the second cylinder chamber 122 are adjacent to each other along the left-right direction. In Figure 4, the first cylinder chamber 121 and the second cylinder chamber 122 are shown by dotted lines. Inside the first cylinder chamber 121, a first piston 141 and a second piston 151 are arranged opposite each other to reciprocate. Inside the second cylinder chamber 122, a third piston 161 and a fourth piston 171 are arranged opposite each other to reciprocate.

[0049] The first engine section 14 includes a first piston 141, a first connecting rod 142, and a first crankshaft 143. The first connecting rod 142 rotatably connects the first piston 141 and the first crankshaft 143.

[0050] The second engine section 15 is positioned opposite the first engine section 14. The second engine section 15 includes a second piston 151, a second connecting rod 152, and a second crankshaft 153. The second connecting rod 152 rotatably connects the second piston 151 and the second crankshaft 153.

[0051] The third engine section 16 includes a third piston 161, a third connecting rod 162, and a third crankshaft 163. The third connecting rod 162 rotatably connects the third piston 161 and the third crankshaft 163.

[0052] The fourth engine section 17 is positioned opposite the third engine section 16. The fourth engine section 17 includes a fourth piston 171, a fourth connecting rod 172, and a fourth crankshaft 173. The fourth connecting rod 172 rotatably connects the fourth piston 171 and the fourth crankshaft 173.

[0053] The first crankshaft 143 of the first engine section 14 and the third crankshaft 163 of the third engine section 16 are integrally continuous. Therefore, the first piston 141 of the first engine section 14 and the third piston 161 of the third engine section 16 reciprocate simultaneously.

[0054] Similarly, the second crankshaft 153 of the second engine section 15 and the fourth crankshaft 173 of the fourth engine section 17 are integrally continuous. Therefore, the second piston 151 of the second engine section 15 and the fourth piston 171 of the fourth engine section 17 reciprocate simultaneously.

[0055] The engine section 13 has a configuration in which opposing engine sections consisting of a first engine section 14 and a second engine section 15, and opposing engine sections consisting of a third engine section 16 and a fourth engine section 17 are arranged side by side along the left-right direction. The first engine section 14 and the third engine section 16 rotate the first crankshaft 143 and the third crankshaft 163. The second engine section 15 and the fourth engine section 17 rotate the second crankshaft 153 and the fourth crankshaft 173. With this configuration, a large amount of power can be generated even with a compact configuration.

[0056] The extension space 33 is a space that extends laterally upward from the middle of the cylinder chamber 12 in the front-rear direction. The extension space 33 has a first extension space 331 and a second extension space 332. The first extension space 331 is a space that extends upward from the middle of the first cylinder chamber 121 in the front-rear direction. The second extension space 332 is a space that extends upward from the middle of the second cylinder chamber 122 in the front-rear direction. The first extension space 331 and the second extension space 332 are the parts where the valves and plugs are installed, as will be described later. The specific shape of the extension space 33 is shown in Figure 7A, etc.

[0057] The combustion chamber 34 is a space within the cylinder chamber 12 that is sandwiched between the pistons. The combustion chamber 34 has a first combustion chamber 341 and a second combustion chamber 342. The first combustion chamber 341 is a space within the first cylinder chamber 121 that is sandwiched between the first piston 141 and the second piston 151, and where the fuel-air mixture burns. The first combustion chamber 341 is continuous with the first extension space 331. The second combustion chamber 342 is a space within the second cylinder chamber 122 that is sandwiched between the third piston 161 and the fourth piston 171, and where the fuel-air mixture burns. The second combustion chamber 342 is continuous with the second extension space 332.

[0058] Figure 5 is a perspective view showing each valve and the reciprocating mechanism 20. Figure 6 is an exploded perspective view showing each valve and the reciprocating mechanism 20.

[0059] Referring to Figures 5 and 6, the reciprocating mechanism 20 is a mechanism that moves the intake valve 18 and exhaust valve 19, which are located near the aforementioned extension space 33, forward and backward.

[0060] The intake valve 18 has a first intake valve 181 and a second intake valve 182.

[0061] The first intake valve 181 is provided so as to be able to move forward and backward relative to the first extension space 331 from the front side. Two first intake valves 181 are provided here. Each first intake valve 181 is attached to the first intake valve mounting hole 351 shown in Figure 3A. The first intake valves 181 are for drawing in the air-fuel mixture into the first cylinder chamber 121 shown in Figure 4. A spring 381 is attached to each first intake valve 181. The spring 381 biases the first intake valve 181 forward.

[0062] The second intake valve 182 is provided so as to be able to move forward and backward relative to the second extension space 332 from the front side. Two second intake valves 182 are provided here. Each second intake valve 182 is attached to the second intake valve mounting hole 352 shown in Figure 3A. The second intake valves 182 are for drawing in the air-fuel mixture into the second cylinder chamber 122 shown in Figure 4. A spring 382 is attached to each second intake valve 182. The spring 382 biases the second intake valve 182 forward.

[0063] The exhaust valve 19 has a first exhaust valve 191 and a second exhaust valve 192.

[0064] The first exhaust valve 191 is provided so as to be able to move back and forth relative to the first extension space 331 from the rear side. There is one first exhaust valve 191 here. The first exhaust valve 191 is mounted in the first exhaust valve mounting hole 361 shown in Figure 3B. The first exhaust valve 191 is for exhausting the air-fuel mixture from the first cylinder chamber 121 shown in Figure 4. The first exhaust valve 191 is provided with a spring 383. The spring 383 biases the first exhaust valve 191 toward the rear.

[0065] The second exhaust valve 192 is provided so as to be able to move back and forth relative to the second extension space 332 from the rear side. There is one second exhaust valve 192. The second exhaust valve 192 is mounted in the second exhaust valve mounting hole 362 shown in Figure 3B. The second exhaust valve 192 is for exhausting the air-fuel mixture from the second cylinder chamber 122 shown in Figure 4. The second exhaust valve 192 is provided with a spring 384. The spring 384 biases the second exhaust valve 192 toward the rear.

[0066] The number of intake valves 18 is greater than the number of exhaust valves 19. For example, with respect to the first extension space 331, there is one exhaust valve 19 and two intake valves 18. According to this embodiment, the spark plug 26 is exposed to the extension space 33 from the side of the fewer number of exhaust valves 19, allowing for effective use of the space around the extension space 33.

[0067] The forward / backward mechanism 20 mainly comprises a camshaft 21, a first cam, a second cam, a pushrod 24, and a rocker arm 25. The first cam is, for example, an intake cam 23. The second cam is separate from the first cam and is, for example, an exhaust cam 22.

[0068] The camshaft 21 is a steel rod extending in the left-right direction. A driven gear 30 is connected to the left end of the camshaft 21 so as not to rotate relative to it. A crank gear 31 is positioned behind the driven gear 30. The crank gear 31 is connected to the aforementioned second crankshaft 153 so as not to rotate relative to it. A belt 32 is stretched between the driven gear 30 and the crank gear 31. Therefore, when the engine unit 13 shown in Figure 4 is operated and the second crankshaft 153 rotates, the camshaft 21 rotates via the belt 32. This allows the intake valve 18 and exhaust valve 19 to move forward and backward at predetermined timings.

[0069] The intake cam 23 is mounted to the camshaft 21 so as not to rotate relative to it and is configured to move the intake valve 18 forward and backward. The intake cam 23 has a first intake cam 231 and a second intake cam 232.

[0070] The first intake cam 231 is positioned in front of the first intake valve 181. As the first intake cam 231 rotates, the first intake valve 181, which is pushed by the first intake cam 231, moves forward and backward.

[0071] The second intake cam 232 is positioned in front of the second intake valve 182. As the second intake cam 232 rotates, the second intake valve 182, which is pushed by the second intake cam 232, moves forward and backward.

[0072] The exhaust cam 22 is configured to move the exhaust valve 19 forward and backward via a pushrod 24. The exhaust cam 22 has a first exhaust cam 221 and a second exhaust cam 222. The exhaust cam 22 is positioned outside the intake cam 23 in the left-right direction.

[0073] The first exhaust cam 221 is positioned on the camshaft 21 to the left of the first intake cam 231. As will be described later, the rotation of the first exhaust cam 221 causes the first exhaust valve 191 to move forward and backward via the first pushrod 241 and the first rocker arm 251.

[0074] The second exhaust cam 222 is located on the camshaft 21 to the right of the second intake cam 232. As will be described later, the rotation of the second exhaust cam 222 causes the second exhaust valve 192 to move forward and backward via the second pushrod 242 and the second rocker arm 252.

[0075] The push rod 24 is a steel rod extending along the front-rear direction. The push rod 24 has a first push rod 241 and a second push rod 242. The push rod 24 is positioned at the end of the reciprocating mechanism 20 in the left-right direction.

[0076] The first push rod 241 is positioned to the left of the intake valve 18, the exhaust valve 19, and the extension space 33. The front end of the first push rod 241 abuts against the first exhaust cam 221. The rear end of the first push rod 241 abuts against the upper end of the first rocker arm 251. The first push rod 241 is a component that transmits the power generated by the rotation of the first exhaust cam 221 to the first rocker arm 251.

[0077] The second push rod 242 is positioned to the right of the intake valve 18, the exhaust valve 19, and the extension space 33. The front end of the second push rod 242 abuts against the second exhaust cam 222. The rear end of the second push rod 242 abuts against the upper end of the second rocker arm 252. The second push rod 242 is a component that transmits the power generated by the rotation of the second exhaust cam 222 to the second rocker arm 252.

[0078] The rocker arm 25 is rotated by a push rod 24 and is configured to move the exhaust valve 19 forward and backward. The rocker arm 25 has a first rocker arm 251 and a second rocker arm 252.

[0079] Referring to Figure 6, the first rocker arm 251 is rotatably arranged with its intermediate portion in the vertical direction as the pivot point. The upper end of the first rocker arm 251 abuts against the rear end of the first push rod 241. The lower end of the first rocker arm 251 abuts against the rear end of the first exhaust valve 191. The first rocker arm 251 is positioned to tilt upward and outward to the left in the width direction. In this way, the first push rod 241 can be positioned to the left, outward in the width direction. Thus, the intake valve 18, exhaust valve 19, and spark plug 26 can be positioned in the widthwise center of the reciprocating mechanism 20.

[0080] The second rocker arm 252 is rotatably arranged with its intermediate portion in the vertical direction as the pivot point. The upper end of the second rocker arm 252 abuts against the rear end of the second push rod 242. The lower end of the second rocker arm 252 abuts against the rear end of the second exhaust valve 192. The second rocker arm 252 is positioned to tilt upward and outward in the width direction to the right. In this way, the second push rod 242 can be positioned outward in the width direction to the right.

[0081] The spark plug 26 is located on the side where the exhaust valve 19 is provided, that is, on the rear side of the extension space 33. The tip of the spark plug 26 is located inside the extension space 33. The spark plug 26 has a first spark plug 261 and a second spark plug 262.

[0082] The first spark plug 261 is positioned to the left of the first exhaust valve 191. The front end of the first spark plug 261 is positioned inside the first extension space 331. Referring to Figure 2B, the first spark plug 261 penetrates the left side wall of the first engine block 111 and is inserted into the rear part 3312 of the first extension space through the first plug mounting hole 371. That is, the rear portion of the first spark plug 261 is exposed to the outside from the left side wall of the first engine block 111. Here, multiple first spark plugs 261 may be positioned in relation to the first extension space 331.

[0083] The second spark plug 262 is positioned to the right of the second exhaust valve 192. The front end of the second spark plug 262 is positioned inside the second extension space 332. Referring to Figure 2B, the second spark plug 262 penetrates the right side wall of the first engine block 111 and is inserted into the rear part 3322 of the second extension space through the second plug mounting hole 372. That is, the rear portion of the second spark plug 262 is exposed to the outside from the right side wall of the first engine block 111. Here, multiple second spark plugs 262 may be positioned in the second extension space 332.

[0084] The first arm 271 is positioned between the first intake valve 181 and the first intake cam 231, referring to Figure 6. The lower front surface of the first arm 271 abuts against the first intake cam 231. The lower rear surface of the first arm 271 abuts against the front ends of the two first intake valves 181. The upper end of the first arm 271 is inserted through the arm shaft 29. With this configuration, the first arm 271 is rotatably positioned with the arm shaft 29 as the pivot point.

[0085] The second arm 272 is positioned between the second intake valve 182 and the second intake cam 232. The lower front surface of the second arm 272 abuts against the second intake cam 232. The lower rear surface of the second arm 272 abuts against the front ends of the two second intake valves 182. The upper end of the second arm 272 is inserted through the arm shaft 29. With this configuration, the second arm 272 is rotatably positioned with the arm shaft 29 as the pivot point.

[0086] The intake valve 18 and exhaust valve 19 close the extension space 33 when no driving force is applied by the reciprocating mechanism 20. Specifically, the first intake valve 181 closes the first extension space 331 by the biasing force of the spring 381 when it is not being pushed by the first intake cam 231 and the first arm 271. The first exhaust valve 191 closes the first extension space 331 by the biasing force of the spring 383 when it is not being pushed by the first exhaust cam 221, the first push rod 241 and the first rocker arm 251. The second intake valve 182 closes the second extension space 332 by the biasing force of the spring 382 when it is not being pushed by the second intake cam 232 and the second arm 272. If the second exhaust valve 192 is not being pushed by the second exhaust cam 222, the second push rod 242, and the second rocker arm 252, the biasing force of the spring 384 closes the second extension space 332.

[0087] Figure 7A is a perspective view of the second cylinder chamber 122 and the second extension space 332, etc., as seen from the rear upper side. Here, the second cylinder chamber 122 and the second extension space 332 are shown by dotted lines. The second extension space 332 is a space that extends upward from the central part of the second cylinder chamber 122 in the front-rear direction. The second exhaust valve 192 and the second spark plug 262 are located on the rear side of the second extension space 332.

[0088] Figure 7B is a perspective view of the second cylinder chamber 122 and the second extension space 332, etc., as seen from the front and above. Here, the second cylinder chamber 122 and the second extension space 332 are shown by dotted lines. Two second intake valves 182 are connected to the front surface of the second extension space 332.

[0089] The engine section 13, the first engine section 14, the second engine section 15, and the reciprocating mechanism 20, as described above, operate by repeatedly performing the intake stroke, compression stroke, combustion stroke, and exhaust stroke as follows.

[0090] In the intake stroke, as shown in Figure 4, the first piston 141 and the second piston 151 move from the center outward within the first cylinder chamber 121, drawing a mixture of fuel and air into the first cylinder chamber 121. Simultaneously, the first crankshaft 143 and the second crankshaft 153 rotate. As shown in Figure 5, in the intake stroke, in the reciprocating mechanism 20, the first intake valve 181 opens the first extension space 331, while the first exhaust valve 191 closes the first extension space 331. Specifically, the crank gear 31 rotates, and consequently, the driven gear 30 on which the belt 32 is mounted also rotates. As a result, the camshaft 21 connected to the driven gear 30 rotates together with the first intake cam 231. The rotation of the first intake cam 231 pushes the first arm 271 and the first intake valve 181 backward. As a result, the front end portion of the first intake valve 181 is pushed into the first extension space 331, and the first intake valve mounting hole 351 shown in Figure 3A opens. Therefore, the air-fuel mixture can be drawn into the first cylinder chamber 121 via the first intake valve mounting hole 351 and the first extension space 331 shown in Figure 3A.

[0091] In the compression stroke, as shown in Figure 4, the inertia of the rotating first crankshaft 143 and second crankshaft 153 pushes the first piston 141 and second piston 151 toward the center, compressing the air-fuel mixture inside the first cylinder chamber 121. Referring to Figure 5, in the reciprocating mechanism 20, the first intake valve 181 closes the first extension space 331, and the first exhaust valve 191 also closes the first extension space 331. Specifically, as the camshaft 21 rotates further, the first intake cam 231 stops pushing the first intake valve 181 via the first arm 271. As a result, the biasing force of the spring 381 displaces the first intake valve 181 forward, closing the first intake valve mounting hole 351 shown in Figure 3A. On the other hand, the first exhaust cam 221 does not push the first exhaust valve 191 via the first push rod 241 and the first rocker arm 251. Therefore, the first exhaust valve 191 is positioned to the rear due to the biasing force of the spring 383, closing the first extension space 331. Consequently, the first extension space 331 and the first cylinder chamber 121 are closed, and the air-fuel mixture can be compressed inside the first cylinder chamber 121.

[0092] During the combustion stroke, the first spark plug 261 shown in Figure 5 ignites in the first extension space 331, causing the fuel-air mixture to burn inside the first extension space 331 and the first cylinder chamber 121 shown in Figure 4. This pushes the first piston 141 and the second piston 151 to their outer ends, which are at bottom dead center. Referring to Figure 5, in the reciprocating mechanism 20, similar to the compression stroke, the first intake valve 181 closes the first extension space 331, and the first exhaust valve 191 also closes the first extension space 331. That is, the state of the first intake valve 181 and the first exhaust valve 191 is the same as in the compression stroke described above.

[0093] In the exhaust stroke, referring to Figure 4, the inertia of the rotating first crankshaft 143 and second crankshaft 153 pushes the first piston 141 and second piston 151 inward, and the post-combustion gases present inside the first cylinder chamber 121 are discharged to the outside. Referring to Figure 5, the reciprocating mechanism 20 causes the first intake valve 181 to close the first extension space 331, while the first exhaust valve 191 opens the first extension space 331. Specifically, the first intake cam 231 does not push the first intake valve 181 via the first arm 271, and the biasing force of the spring 381 causes the first intake valve 181 to close the first extension space 331. On the other hand, the first exhaust cam 221 pushes the push rod 24 backward, and the resulting rotation of the first rocker arm 251 pushes the first exhaust valve 191 forward. As a result, the first exhaust valve 191 opens the first extension space 331. This causes the combustion gas inside the first cylinder chamber 121 to be released to the outside through the first exhaust valve mounting hole 361 shown in Figure 3B.

[0094] The same applies to the third engine section 16, the fourth engine section 17, the second intake valve 182, and the second exhaust valve 192.

[0095] In the engine unit 13, the stroke can be divided by two first pistons 141 and second pistons 151 that reciprocate within a single first cylinder chamber 121. Therefore, the compression ratio of the fuel mixture can be increased compared to a conventional engine. Also, since the first piston 141 and second piston 151 face each other within the first cylinder chamber 121, a cylinder head required in a typical engine is unnecessary, resulting in a simple and lightweight engine unit 13. Furthermore, each component of the engine unit 13, namely the first piston 141 and second piston 151, the first crankshaft 143 and second crankshaft 153, etc., are arranged and operate in opposition to each other. As a result, vibrations generated from each component of the engine unit 13 cancel each other out, reducing the vibrations generated from the engine unit 13 as a whole to the outside. Therefore, by mounting an engine unit 13 with such a structure on an aircraft, it is possible to achieve miniaturization, weight reduction, and reduced vibration of the aircraft. In particular, reducing vibrations prevents adverse effects on precision equipment such as attitude control, motor output control, and GPS sensors. It also prevents damage to cargo transported by the aircraft due to vibrations.

[0096] Referring to Figure 5, according to this embodiment, the intake valve 18 is moved forward and backward by the intake cam 23, and the exhaust valve 19 is moved forward and backward by the push rod 24. This allows the reciprocating mechanism 20 to be positioned near the cylinder chamber 12 even when there are strict geometric constraints near the cylinder chamber 12. Furthermore, by using the push rod 24, the number of camshafts 21 can be reduced, thereby simplifying the configuration of the engine 10.

[0097] Furthermore, according to this embodiment, since the intake valve 18 and exhaust valve 19 are arranged on either side of the extension space 33, the intake valve 18 and exhaust valve 19 are closely spaced. However, since the intake valve 18 or exhaust valve 19 is moved back and forth via a push rod, the configuration around the extension space 33 can be simplified.

[0098] Furthermore, according to this embodiment, even when multiple cylinder chambers 12 are adjacent to each other and a large number of intake valves 18 and exhaust valves 19 are arranged, the overall configuration of the engine 10 can be simplified by optimizing the configuration of the camshaft 21 and pushrods.

[0099] Figure 8 is a cross-sectional view along the BB cross-section line in Figure 4, showing the wall portion of the engine block 11 that forms the first cylinder chamber 121 and the first extension space 331.

[0100] As described above, the first cylinder chamber 121 is a space that is substantially cylindrical in shape. The first cylinder chamber 121 has a front part 1211 on the front side and a rear part 1212 connected to the rear end of the front part 1211. At approximately the center of the first cylinder chamber 121 in the front-rear direction, the first extension space 331 protrudes upward from the upper surface of the first cylinder chamber 121. The front part 1211, the rear part 1212, and the first extension space 331 are in communication with each other.

[0101] The first cylinder chamber 121 and the first extension space 331 in this configuration are spaces surrounded by walls formed inside the engine block 11.

[0102] Specifically, the front portion 1211 of the first cylinder chamber is a substantially cylindrical space surrounded by the first cylinder wall portion 1281. The first cylinder wall portion 1281 is a cylindrical wall formed inside the first engine block 111. The front and rear ends of the first cylinder wall portion 1281 are open.

[0103] The rear portion 1212 of the first cylinder chamber is a roughly cylindrical space surrounded by the second cylinder wall portion 2282. The second cylinder wall portion 2282 is a cylindrical wall formed inside the second engine block 112. The front and rear ends of the second cylinder wall portion 2282 are open.

[0104] The first extension space 331 is the space enclosed by the first extension wall portion 1291 and the second extension wall portion 2292. The first extension wall portion 1291 is a roughly tongue-shaped portion that extends upward from the upper end of the first cylinder wall portion 1281 at the rear end of the first cylinder wall portion 1281. The second extension wall portion 2292 is a roughly tongue-shaped portion that extends upward from the upper end of the second cylinder wall portion 2282 at the front end of the second cylinder wall portion 2282.

[0105] The first cylinder chamber 121 is a substantially cylindrical space having a first central axis 1213 extending along the front-rear direction. The first cylinder chamber 121 has a first side surface 1214. The first side surface 1214 is a surface formed by the inner surfaces of the first cylinder wall 1281 and the second cylinder wall 2282. A first extension space 331 extends from the first side surface 1214. Specifically, the first extension space 331 is a space that extends upward in a direction perpendicular to the first central axis 1213 of the first cylinder chamber 121. The first extension space 331 communicates with the first cylinder chamber 121.

[0106] The same applies to the second cylinder chamber 122 mentioned above.

[0107] Although embodiments of the present invention have been described above, the present invention is not limited thereto, and modifications are possible without departing from the spirit of the invention. Furthermore, the above-described embodiments can be combined with each other.

[0108] For example, as shown in Figure 5, the exhaust valve 19 is moved forward and backward by the push rod 24. However, it is also possible to configure the system so that the intake valve 18 is moved forward and backward by the push rod 24, and the exhaust valve 19 moves forward and backward without the push rod 24.

[0109] Furthermore, although the aforementioned engine 10 has multiple cylinder chambers 12, the number of cylinder chambers 12 can also be reduced to one. [Explanation of Symbols]

[0110] 10 Engines 11 Engine Block 111 First engine block 112 Second engine block 113 Third engine block 114. Fourth engine block 12 Cylinder Chambers 121 First Cylinder Chamber 1211 Front of the first cylinder chamber 1212 Rear of the first cylinder chamber 122 Second Cylinder Chamber 1221 Front of the second cylinder chamber 1222 Rear of the second cylinder chamber 1213 1st central axis 1214 1st side 1291 1st extension wall section 13 Engine section 14. First Engine Section 141 First Piston 142 First Connecting Rod 143 First Crankshaft 15. Second Engine Section 151 Second piston 152 Second Connecting Rod 153 Second crankshaft 16. Third Engine Section 161 Third piston 162 Third Connecting Rod 163 Third crankshaft 17. Engine No. 4 171 Piston No. 4 172 Fourth Connecting Rod 173 Fourth crankshaft 18 Intake valve 181 First intake valve 182 Second intake valve 19 Exhaust valve 191 First exhaust valve 192 Second exhaust valve 20 Advancement / retraction mechanism 21 Camshaft 22 Exhaust Cam 221 First exhaust cam 222 Second exhaust cam 1281 First cylinder wall 2282 Second cylinder wall 2292 2nd extension wall section 23 Intake Cam 231 First intake cam 232 Second intake cam 24 Pushrods 241 First pushrod 242 Second pushrod 25 Rocker Arms 251 First rocker arm 252 Second rocker arm 26 Spark plugs 261 First spark plug 262 Second Spark Plug 271 First Arm 272 Second Arm 29 Arm Shaft 30 Driven gear 31 Crank Gear 32 belts 33 Extension space 331 1st extension space 3311 First extension space front 3312 First extension space rear 332 Second extension space 3321 Second extension space front 3322 Second extension space rear 34 Combustion chamber 341 First Combustion Chamber 342 Second Combustion Chamber 35 Intake valve mounting hole 351 First intake valve mounting hole 352 Second intake valve mounting hole 36 Exhaust valve mounting hole 361 First exhaust valve mounting hole 362 Second exhaust valve mounting hole 37 Plug mounting holes 371 First plug installation hole 372 Second plug installation hole 381 Spring 382 Spring 383 Spring 384 Spring 40 First contact surface 41 Second contact surface

Claims

1. The engine comprises a cylinder chamber, an intake valve, an exhaust valve, and a reciprocating mechanism for moving the intake valve and the exhaust valve forward and backward. The reciprocating mechanism includes a camshaft, a first cam, a second cam, a push rod, and a rocker arm. The first cam is fixed to the camshaft and configured to move either the intake valve or the exhaust valve forward and backward. The second cam is separate from the first cam and configured to move the push rod forward and backward. The rocker arm is rotated by the push rod, and the intake valve The valve and the exhaust valve are configured to move forward and backward, the first cam moves a plurality of the intake valves forward and backward, the second cam moves the exhaust valve forward and backward via the push rod, the inside of the cylinder chamber is arranged such that pistons facing each other along the front-rear direction when the axial direction of the cylinder chamber is the front-rear direction move back and forth, and there is an extension space that extends laterally from the middle of the cylinder chamber in the front-rear direction, the intake valve is provided so as to be able to move forward and backward in relation to the extension space from the front side, and the exhaust valve The lube is provided to be able to move back and forth from the rear side toward the extension space, and the cylinder chamber has a first cylinder chamber and a second cylinder chamber adjacent to the first cylinder chamber, the first cylinder chamber houses a first piston and a second piston so as to move back and forth, the second cylinder chamber houses a third piston and a fourth piston so as to move back and forth, and has a first extension space that extends laterally from the middle of the first cylinder chamber in the front-rear direction, and the second cylinder chamber extends laterally from the middle of the second cylinder chamber in the front-rear direction An engine having an extending second extension space, wherein the intake valve comprises a first intake valve and a second intake valve, the exhaust valve comprises a first exhaust valve and a second exhaust valve, the first intake valve is provided so as to be able to move back and forth relative to the first extension space from the front side, the first exhaust valve is provided so as to be able to move back and forth relative to the first extension space from the rear side, the second intake valve is provided so as to be able to move back and forth relative to the second extension space from the front side, and the second exhaust valve is provided so as to be able to move back and forth relative to the second extension space from the rear side.

2. (delete)

3. (delete)

4. (delete)

5. The engine according to claim 1, characterized in that the number of intake valves is greater than the number of exhaust valves, and the spark plugs are arranged to be exposed on the side of the extension space where the exhaust valves are provided.

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