Axial internal combustion engine

Abstract

The axial internal combustion engine comprises at least one cylinder (100); a piston assembly (110) defining within the cylinder a combustion chamber (200) in which a fuel-air-oil mixture is compressed during one stroke of the piston assembly (110) and a pump chamber (300) for suctioning air to be suctioned into the combustion chamber (200) during said stroke of the piston assembly (110) to subsequently deflate the compressed fuel-air-oil mixture in the combustion chamber (200). The piston assembly (110) includes a piston head (111), a piston body (112), and a connecting rod (135) connected to the piston head (111) and having a cam follower (150) at one end (140) for support on a surface (410) of the single power cam (400). Displacement of the piston assembly (110) within the cylinder (100) rolls the cam follower (150) onto the surface (410), thereby rotating the power cam (400).

Description

[0001] This application enjoys the benefits of European patent application EP22382557.1 filed on June 9, 2022. Technical Field

[0002] The present disclosure relates to engines. More specifically, the present disclosure relates to axial internal combustion engines. The internal combustion engines of the present invention can be applied to automobiles, aircraft (such as model airplanes) and many other different applications. Background Art

[0003] The axial internal combustion engine of the present invention may be referred to as a one stroke internal combustion engine. One stroke internal combustion engines are known in the art. In a one stroke internal combustion engine, each piston stroke produces a combustion. The intake, compression, power and exhaust strokes occur in a single rotation of the output shaft or crankshaft. Each piston stroke is a power stroke, so that only one power stroke is required to continuously rotate the output shaft or crankshaft to complete a complete cycle.

[0004] An example of a one-stroke internal combustion engine is disclosed in US20030121482A1. The engine includes a combustion chamber and a compression chamber. A compression member is provided in the compression chamber for defining a first combustion subchamber and a second combustion subchamber. The piston is slidably arranged in the combustion chamber and is connected to the compression member for defining a first combustion subchamber and a second combustion subchamber. The movement of the piston toward the first combustion subchamber causes a first fuel-air mixture to flow from the second combustion subchamber into the second combustion subchamber for subsequent combustion therein, while a second fuel-air mixture is sucked into the first compression chamber. The movement of the piston toward the second combustion subchamber causes a second fuel-air mixture to flow from the first combustion subchamber into the first combustion subchamber for subsequent combustion therein, while a third fuel / air mixture is sucked into the second compression chamber.

[0005] A further example of a one-stroke internal combustion engine is disclosed in US2016025001A1. It includes an intake chamber, a compression chamber, a combustion chamber and an exhaust chamber operating in a linear, rotating or opposed piston configuration. As the pistons are alternately ignited, the crankshaft is driven.

[0006] EP3066312B1 filed by the same applicant as the present application relates to an opposed piston engine capable of completing a full cycle only once. For this purpose, mutually opposed power cams are connected to respective rotating shafts so that the reciprocating motion of the piston acting on the power cams transmits a rotational motion to the rotating shaft to drive the engine.

[0007] Axial or cylinder engines are known in the art, such as the engine disclosed in US1042018, whose cylinders are arranged around and parallel to a central axis, like the chambers in a revolver cylinder. Although such engines have a small frontal area, good balance and good compactness, they are usually found to have problems such as maintenance difficulties on the swash plate used to convert piston thrust into rotary motion.

[0008] Although known one-stroke internal combustion engines have been shown to offer many significant advantages, such as smaller displacement and lower emissions, there remains a need for a simpler engine requiring fewer auxiliary parts and having a higher specific power and a higher power-to-weight ratio. Summary of the invention

[0009] An axial internal combustion engine is disclosed herein that meets at least the above needs and achieves further advantages and benefits.

[0010] The axial internal combustion engine of the present invention comprises at least one cylinder, such as two or four. Other suitable numbers of cylinders are possible. The cylinder can be arranged to work in any desired position (such as horizontal, vertical or inclined).

[0011] Each cylinder can slideably accommodate a piston assembly. Therefore, the axial internal combustion engine of the present invention includes as many piston assemblies as cylinders. The piston assembly defines a combustion chamber and a pump chamber in the cylinder. The engine of the present invention is referred to herein as an axial internal combustion engine because the pump chamber in the cylinder is axially arranged relative to the combustion chamber. An engine mount is provided to support one or more cylinders. The engine mount may have an opening for accommodating the piston body.

[0012] The pump chamber is intended to draw air to be pumped into the combustion chamber. The combustion chamber is intended to compress the fuel-air-oil mixture during one stroke of the piston assembly and then cause explosion of the compressed fuel-air-oil mixture.

[0013] The piston assembly includes a piston head, a piston body and a connecting rod. The connecting rod has a first end connected to the piston head. A cam follower is attached to the piston body. The cam follower can be, for example, a roller rotatably mounted in the piston body.

[0014] The piston head is preferably of frustoconical shape. A connecting rod connects the piston head and the piston body so that the swinging motion is limited. Therefore, the load is borne by the piston body, not by the piston head, and there is no side load against the cylinder, so there is less wear. The installation of the piston assembly in the cylinder becomes convenient, and the opening and closing of the port is also more efficient.

[0015] A single power cam is provided. The cam follower provided at the second end of the connecting rod is intended to bear (ie roll) directly on the surface of the single power cam. Roller bearings are preferably provided to rotate the single power cam.

[0016] The piston assembly is configured to move in a first direction within the cylinder so that the fuel-air-oil mixture is sucked into the pump chamber through the intake port while the transfer port and the exhaust port are closed, then move in a second opposite direction for pumping the fuel-air-oil mixture into the combustion chamber through the transfer port, then move in the first direction again, wherein the fuel-air-oil mixture is compressed in the combustion chamber by the piston assembly, then move in the second direction again within the cylinder due to ignition of the compressed fuel-air-oil mixture, thereby performing a power stroke and opening the exhaust port so that combustion gases are exhausted from the combustion chamber. Then, a fresh fuel-air-oil mixture is pumped into the pump chamber again for a subsequent cycle.

[0017] The displacement of the piston assembly in the cylinder in a second opposite direction causes the cam follower to roll onto the surface of the single-power cam, thereby rotating the single-power cam. This in turn causes the output shaft connected to the single-power cam to be rotated. Subsequent strokes of the piston assembly repeat this process.

[0018] Counter cams may be provided in the output shaft for accommodating corresponding counter cam followers mounted in the piston body coaxially with the cam followers of the piston assembly. The counter cams have a smaller diameter than the power cams. The counter cams are intended to prevent the piston assembly from losing contact with the single power cam.

[0019] With the above configuration, no crankshaft is required, thereby achieving an advantageous compact design with a high power-to-weight ratio. Providing a single power cam makes the engine efficient and powerful, with improved mass balance and low vibration.

[0020] Within the meaning of this disclosure, one-stroke refers to an engine that requires a single power stroke to rotate the power cam 180° to complete the cycle.

[0021] The cam follower may be provided with at least one channel for the passage of lubricant. Furthermore, the cam follower may preferably be arranged to act close to a central area of ​​the surface of the single power cam. Other configurations are also possible.

[0022] As described above, a plurality of cylinders may be provided, each of which may slidably contain a corresponding piston assembly. In this case, a single power cam is still associated with all of the piston assemblies. Also in this case, each piston assembly in each cylinder defines a pump chamber and a combustion chamber as described above.

[0023] The cylinder may include a single crankcase as part of the pump chamber. The single crankcase is associated with the piston assembly. A common crankcase may be provided for the cylinders. The common crankcase may be integrally formed with the engine mount, or it may be a separate part.

[0024] Preferably, a fuel control device is provided to regulate the amount of fuel and / or air entering the cylinder. The fuel control device may be, for example, at least one carburettor or a fuel injection system. In any case, it may be advantageous to arrange the fuel control device in the above-mentioned common crankcase (if provided).

[0025] At least one intake port may be provided for drawing a fuel-air-oil mixture into a pump chamber of the cylinder. At least one transfer port may be provided for flowing the fuel-air-oil mixture from the pump chamber of the cylinder into the combustion chamber. At least one exhaust port may be provided for exhausting combustion gases from the engine. The exhaust port may preferably be arranged to open before the transfer port opens and to close after the transfer port closes.

[0026] One or more longitudinal guides may be advantageously provided for guiding the piston body of the piston assembly as it moves in the cylinder. Optionally, at least one longitudinal guide provided in the outermost portion of the engine mount is larger than other longitudinal guides provided at other locations of the piston assembly.

[0027] In the above-described axial internal combustion engine, the clearance volume, i.e. the portion of the cylinder volume not swept by the piston, is advantageously very small. This results in a higher compression ratio, volumetric efficiency and enhanced cooling capacity. It has been found that the cost is significantly lower than that of a standard internal combustion engine for the same power. The engine of the invention is light and easy to rotate, which is very useful for aircraft such as model airplanes. The engine of the invention also finds advantageous application in automobiles and many other fields. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] A non-limiting example of an axial internal combustion engine of the present invention will be described below with reference to the accompanying drawings.

[0029] In the attached picture:

[0030] Figure 1 It is an overall perspective view of an example of an axial internal combustion engine of the present invention;

[0031] Figure 2 and Figure 3 They are Figure 1 A front view and a side view of an example of an internal combustion engine shown in;

[0032] Figure 4 , Figure 5 yes Figures 1 to 3A cross-sectional view of an axial internal combustion engine is shown in;

[0033] Figure 6a yes Figures 1 to 5 A perspective view of an axial internal combustion engine shown in FIG. 1 with the cylinder removed to show the piston assembly;

[0034] Figure 6b yes Figure 6a A partial perspective view of one of the piston assemblies shown in FIG.

[0035] Figure 6c and Figure 6d is a perspective view of the cylinder showing the transfer and exhaust ports;

[0036] Figures 7 to 10 are top, bottom, perspective and side views of a piston assembly with the cylinder removed to show the piston assembly;

[0037] Figures 9a to 9c The parts of the piston assembly are shown to illustrate how the piston head connects to the connecting rod;

[0038] Fig.11 and Fig.12 It is a perspective view of a single crankcase seen from different sides;

[0039] Fig.13 and Fig.14 It is a partial perspective view of a piston assembly engine seen from different sides;

[0040] Fig.15 and Fig.16 is a perspective view of the engine mount seen from different sides; and

[0041] Fig.17 and Fig.18 It is a three-dimensional diagram of a single power cam. DETAILED DESCRIPTION

[0042] Figure Figures 1 to 16 A non-limiting example of an axial internal combustion engine 10 for a model aircraft is shown in FIG. 1 and is described as follows.

[0043] The axial internal combustion engine 10 includes four cylinders 100, each cylinder having a Figure 1 and Figure 2 The cylinder head 250 shown in FIG. Figures 1 to 3As shown in FIG. 6 , the cylinders 100 are supported by an engine mount 240. Depending on the specific application of the engine 10, the number of cylinders 100 may of course also be different. As shown in FIG. 6 , the engine mount 240 has an opening 500 suitable for accommodating the piston body 112. Thus, the piston body 112 can be completely accommodated in the engine mount 240. The opening 500 is defined by walls 510 spaced apart inside the engine mount 240.

[0044] like Figures 4 to 5 6 to 7, a piston assembly 110 is slidably received within each cylinder 100. Fig.10 The piston assembly 110 is shown in detail in FIG. In use, the piston assembly 110 moves along the Fig.13 and Fig.14 The longitudinal axis L of the cylinder 100 depicted in FIG. 1 reciprocates.

[0045] like Figures 6a to 10 As shown in FIG. 1 , the piston assembly 110 includes a piston head 111, a piston body 112, and a connecting rod 135. A cam follower 150 is attached to the piston body 112. Figures 1 to 3 , when in use, the connecting rod 135 connects the piston head 111 and the piston body 112 together. Figure 9a , Figure 9b , Fig.9c The connecting rod 135 has one end connected to the piston head 111 through a connecting clamp 116. The connecting clamp 116 has two arms, such as Figure 9b In use, the arm of the connecting clip 116 passes through the opening 117 formed in the connecting body 118 formed inside the piston head 111. In turn, the arm of the connecting clip 116 is received in the annular groove 119 formed at the end of the connecting rod 135 and is pressed against the annular groove 119 formed at the end of the connecting rod 135, as shown in FIG. Figure 9a , Figure 9b and Fig.9c In this way, the connecting rod 135 is connected to the piston head 111 in a manner having a small degree of freedom of swinging.

[0046] like Figure 6b As shown in FIG. 1 , each piston assembly 110 defines a combustion chamber 200 and a pumping chamber 300 within the corresponding cylinder 100 .

[0047] Combustion chamber 200 may also be referred to herein as a compression chamber because it is configured to contain a fuel-air-oil mixture that will be compressed by piston assembly 110 during a stroke of internal combustion engine 10 .

[0048] The pump chamber 300 is axially arranged relative to the combustion chamber 200 along the longitudinal axis L of the cylinder 100. The pump chamber 300 may also be referred to as a sweeping chamber because it is configured to draw air from the common crankcase 160 into the combustion chamber 200 during the stroke of the internal combustion engine 10.

[0049] Now refer to the accompanying drawings Figure 6a-Figure 10 , which shows a piston assembly 110, wherein the piston head 111 is connected to the piston body 112 via a connecting rod 135 as described above. The connecting rod 135 has a first end connected to the piston head 111 and a second end connected to the piston body 112.

[0050] The piston body 112 is provided with a plurality of parallel channels 113, such as Fig. 9 and Fig.10 The channel 113 is further provided with a port 114 for cooling and conveying lubricant. Fig.16 2, the passage 113 in the piston body 112 is configured to receive a longitudinal guide 115 formed in the engine mount 240. In use, the longitudinal guide 115 guides the piston body 112 as it moves within the engine mount 240. The longitudinal guide 115 located at the outermost portion of the engine mount 240 is larger than other longitudinal guides 115 located at other locations of the engine mount 240.

[0051] like Fig.17 and Fig.18 As shown in FIG. 4 , a single power cam 400 is provided. The single power cam 400 is attached to an output shaft 440. As shown in the figure, the output shaft 440 is in turn attached to the propeller carrier.

[0052] The cam follower 150 of each piston assembly 110 is intended to be directly supported on the surface 410 in the single-power cam 400. Specifically, the cam follower 150 is arranged to act near the central area of ​​the surface of the single-power cam 400. In operation, the displacement of the piston assembly 110 in the cylinder 100 causes the cam follower 150 of the piston assembly 110 to roll onto the surface 410 of the single-power cam 400, thereby causing the single-power cam 400 to rotate with the output shaft 440. Figure 4 As shown in FIG. 4 , the single power cam 400 is supported in rotation by a roller bearing 430 .

[0053] Due to the above configuration, no crankshaft is required, thus achieving a compact design with a high power-to-weight ratio and improved mass balance as well as low vibrations.

[0054] Reference now Fig.17 and Fig.18, a reverse cam 450 is formed in the output shaft 440. The reverse cam 450 is intended to receive a corresponding reverse cam follower 455. The opening 500 in the engine mount 240 is adapted to receive the reverse cam 450. Figures 7 to 10 As shown in FIG. 1 , the reverse cam follower 455 is coaxially mounted in the piston body 112 with the cam follower 150 of the piston assembly 110. Figures 7 to 10 As shown in FIG. 4 , the diameter of the reverse cam 450 is smaller than the diameter of the power cam 400. The reverse cam 450 is intended to prevent the piston assembly 110 from losing contact with the single power cam 400.

[0055] Each cylinder 100 includes a single crankcase as part of the pump chamber 300. Figure 1 and Figure 3 As shown in FIG. 2 , the above-mentioned common crankcase 160 is also provided as part of the engine mount 240 .

[0056] In order to regulate the amount of fuel and / or air entering the cylinder 100, in particular the pump chamber 300 of the cylinder 100, a fuel control device 170 is provided in the above-mentioned common crankcase 160. In the non-limiting example shown in the figures, the fuel control device 170 comprises one or more carburetors. Other fuel control devices 170 (e.g. based on fuel injection) are also possible.

[0057] like Fig.15 and Fig.16 As shown in FIG. 1 , the fuel-air-oil mixture is drawn into the pump chamber 300 through the intake port 180 formed in the engine mount 240. Figure 6c and Figure 6d As shown in FIG. 1 , a transfer port 185 is provided for allowing the fuel-air-oil mixture to flow from the pump chamber 300 into the combustion chamber 200 within the cylinder 100. Also provided is Figure 6c , Fig.13 and Fig.14 The exhaust port 190 shown in FIG. 1 is used to exhaust the combustion gas out of the engine 10 through the corresponding exhaust pipe 230. The exhaust port 190 is configured to open before the transmission port 185 opens and to close after the transmission port 185 closes.

[0058] In operation, the piston assembly 110 first moves in the first direction within the cylinder along the longitudinal axis L of the cylinder 100, so that the fuel-air-oil mixture from the carburetor 170 is drawn into the pump chamber 300 through the intake port 180, while closing the transfer port 185 and the exhaust port 190. Then, the piston assembly 110 moves in the second opposite direction along the longitudinal axis L of the cylinder 100, thereby pumping the fuel-air-oil mixture into the combustion chamber 200 through the transfer port. Then, the piston assembly 110 moves in the first direction again, wherein the fuel-air-oil mixture is compressed by the piston assembly 110 within the combustion chamber 200. Finally, as the compressed fuel-air-oil mixture is ignited by the spark plug 270, the piston assembly 110 moves in the second direction within the cylinder 100, thereby performing a power stroke and opening the exhaust port 190, so that the combustion gas is discharged from the combustion chamber 200 through the exhaust pipe 230. Then, a fresh fuel-air-oil mixture is pumped into the pump chamber 300 again for a subsequent cycle. This process is repeated for a subsequent stroke of the piston assembly 110, causing the cam follower 150 to roll onto the surface 410 of the single power cam 400, thereby rotating the single power cam 400 and, therefore, rotating the output shaft 440 connected thereto.

[0059] As the piston assembly 110 moves within the cylinder 100, the delivery port 185 and the exhaust port 190 are opened and closed correspondingly. An intake leaf valve is provided in the intake port 180, and the intake leaf valve is driven as the piston assembly 110 moves within the cylinder 100. The intake leaf valve opens and closes under the internal pressure on the cylinder 100.

[0060] Although an example of an internal combustion engine of the present invention has been disclosed herein, other substitutions, modifications, uses and / or their equivalents are also possible. All possible combinations of the examples described herein are also included. For example, other suitable cylinder numbers other than four are also possible.

[0061] The scope of the present disclosure should not be limited by the specific examples disclosed herein, but should be determined only by a fair reading of the claims.

[0062] Reference signs placed between brackets in the claims relative to the drawings are merely intended to increase the intelligibility of the claims and shall not be construed as limiting the scope thereof.

Claims

1. An axial internal combustion engine (10), comprising: - at least one cylinder (100), the at least one cylinder (100) being supported by an engine mount (240); - a piston assembly (110) slidably received in the cylinder (100), the piston assembly (110) defining a combustion chamber (200) and a pump chamber (300) axially arranged with respect to each other, the piston assembly (110) being configured to move in a first direction in the cylinder (100) so that a fuel-air-oil mixture is drawn into the pump chamber (300), then move in a second opposite direction for pumping the fuel-air-oil mixture into the combustion chamber (200), then move again in the first direction, wherein the fuel-air-oil mixture is compressed in the combustion chamber (200) by the piston assembly (110), and then move again in a second direction in the cylinder (100) due to ignition of the compressed fuel-air-oil mixture, The piston assembly (110) comprises: - piston head (111), - a piston body (112), and - a connecting rod (135) having an end (130) connected to the piston head (111); - a cam follower (150) attached to the piston body (112) to bear directly against a surface (410) of the single-power cam (400), whereby displacement of the piston assembly (110) within the cylinder (100) causes the cam follower (150) to roll onto the surface (410) of the single-power cam (400), thereby causing the single-power cam (400) to rotate.

2. The engine (10) according to claim 1, wherein the engine mount (240) has an opening (500) for accommodating the piston body (112).

3. An engine (10) according to claim 1 or 2, wherein the engine (10) includes a plurality of cylinders (100), the plurality of cylinders (100) having corresponding piston assemblies (110) and a single power cam (400) associated with the piston assemblies (110), a pump chamber (300) and a combustion chamber (200) defined by each piston assembly (110) in each cylinder (100).

4. An engine (10) according to any one of the preceding claims, wherein the engine (10) comprises a fuel control device (170) for regulating the amount of fuel and / or air entering the cylinder (100).

5. The engine of claim 4, wherein the fuel control device (170) comprises at least one carburetor or a fuel injection system.

6. The engine (10) according to any one of claims 2 to 5, wherein the engine (10) comprises a common crankcase (160) for the cylinders (100).

7. The engine (10) of claim 6, wherein the fuel control device (170) is disposed in the common crankcase (160).

8. An engine (10) according to any one of the preceding claims, wherein the cylinder (100) further comprises at least one intake port (180) for drawing the fuel-air-oil mixture into the pump chamber (300) of the cylinder (100), at least one transfer port (185) for allowing the fuel-air-oil mixture to flow from the pump chamber (300) of the cylinder (100) into the combustion chamber (200), and at least one exhaust port (190) for exhausting combustion gases from the combustion chamber (200).

9. The engine (10) of claim 8, wherein the exhaust port (190) is arranged to open before the transfer port (185) opens and to close after the transfer port (185) closes.

10. The engine (10) according to any one of the preceding claims, wherein the cam follower (150) is provided with at least one channel (113) for the passage of lubricant.

11. An engine (10) according to any one of the preceding claims, wherein the cam follower (150) is arranged to act close to a central area of ​​the surface (410) of the single power cam (400).

12. The engine (10) according to any one of the preceding claims, wherein the engine (10) comprises a roller bearing (430) for rotating the single power cam (400).

13. The engine (10) according to any one of the preceding claims, wherein a connecting rod (135) is provided for connecting the piston head (111) and the piston body (112).

14. An engine (10) according to any one of the preceding claims, wherein at least one longitudinal guide (115) is provided for guiding the piston body (112) of the piston assembly (110) when the piston body (112) of the piston assembly (110) moves in the engine mount (240).

15. The engine (10) according to claim 14, wherein a plurality of longitudinal guides (115) are provided for guiding the piston body (112) of the piston assembly (110) when the piston body (112) of the piston assembly (110) moves in the engine mount (240), and at least one longitudinal guide (115) located in the outermost portion of the engine mount (240) is larger than the other longitudinal guides (115).

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