Free-piston engine

Abstract

A free-piston engine, comprising at least one cylinder group, wherein each cylinder group comprises two cylinders arranged opposite each other; pistons of the two cylinders in each group are connected to each other by means of a push rod (3); and each push rod (3) is provided with a rack (31). The free-piston engine further comprises a transmission unit, which comprises a swing gear (4), a first one-way clutch (5a), a second one-way clutch (5b), a first power output member (6a) and a second power output member (6b), wherein the swing gear (4) is rotationally arranged about a fixed axis, the swing gear (4) meshes with the rack (31), the swing gear (4) is connected to the first power output member (6a) by means of the first one-way clutch (5a), and the swing gear (4) is connected to the second power output member (6b) by means of the second one-way clutch (5b). In the free-piston engine, a complex transmission mechanism composed of a push rod, a crankshaft and the like in the prior art is eliminated, and a reciprocating linear motion of a piston is converted into a rotary motion, so as to output power in a rotational form.

Description

A free piston engine Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a free piston engine. Background Technology

[0002] Hybrid electric vehicles (HEV), plug-in hybrid electric vehicles (PHEV), and range-extended electric vehicles (REEV) are the main technological routes for energy-saving and new energy vehicles. What they have in common is that they all contain a piston engine with a crankshaft and convert fuel (such as gasoline, diesel, methanol, natural gas, hydrogen, etc.) into mechanical energy. Moreover, HEV, PHEV, and REEV all need to maximize the energy conversion efficiency of the engine.

[0003] The power generated by existing piston engines with crankshafts is transmitted from the piston to the pushrod, which then transmits the power to the crankshaft via the crank, thus converting it into rotational motion and outputting power. Due to the limitations of the pushrod and crankshaft, the piston stroke is fixed, so the compression ratio cannot be adjusted or optimized according to power requirements, which limits the system's thermal efficiency. Furthermore, when the piston is working, the pushrod applies a reaction force, the lateral component of which presses the piston tightly against the cylinder wall, greatly increasing friction and energy loss. Furthermore, constrained by their operating mode, most piston engines are two-stroke engines, including a compression stroke and a power stroke. At the end of the compression stroke (top dead center), the compressed gas mixture in the cylinder is ignited, and at the end of the power stroke (bottom dead center), scavenging occurs to expel exhaust gas and introduce air and gas. However, the scavenging time is very short, requiring air pressurization to force the exhaust gas out of the cylinder. Alternatively, during the gas exchange process, some exhaust gas may remain in the cylinder, while some fresh air may be entrained in the exhaust stream. This situation is called short-circuit loss, which also affects the efficiency of the entire power system.

[0004] At the beginning of the power stroke, the pressure inside the cylinder is at its highest, but the crankshaft is near top dead center, the pushrod lever arm on the crankshaft is very small, resulting in a smaller torque and therefore a smaller power output. Simultaneously, the energy contained in the high-temperature, high-pressure combustion gases is released more slowly, and energy losses due to gas leakage and heat loss also increase. Towards the end of the power stroke, the crankshaft is near bottom dead center, the pushrod lever arm on the crankshaft is also small, and the pressure inside the cylinder is lower, resulting in another lower power output. This reduces the engine's power density and increases power output fluctuations.

[0005] Furthermore, the loads between the pushrod and the crankshaft, and between the crankshaft and the housing, are substantial, resulting in significant frictional losses. High-pressure oil bearings are required, which in turn necessitate a high-pressure oil source and a high-pressure oil pump. This necessitates additional energy to drive the high-pressure oil pump, leading to a reduction in engine output power and efficiency. Since the high-pressure oil bearings of the pushrod and crankshaft are both moving parts, complex high-pressure oil circuits are needed to deliver high-pressure lubricating oil to them. These circuits must pass through moving components such as the crankshaft, crankshaft, and pushrod, increasing the manufacturing difficulty and cost of these components. Summary of the Invention

[0006] To address the aforementioned problems, this invention provides a free piston engine that eliminates the complex transmission mechanism consisting of pushrods and crankshafts found in existing technologies, and converts the linear reciprocating motion of the piston into rotational motion to output rotational power, thereby improving engine efficiency.

[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0008] This invention provides a free piston engine, comprising at least one cylinder bank, each cylinder bank including two opposing cylinders, the pistons of the two cylinders in each bank being connected by a push rod, the push rod being provided with a rack, and a transmission unit; the transmission unit includes a rocker gear, a first one-way clutch, a second one-way clutch, a first power output component, and a second power output component, the rocker gear being fixed-axis rotatable and meshing with the rack; the rocker gear being connected to the first power output component via the first one-way clutch, and the rocker gear being connected to the second power output component via the second one-way clutch.

[0009] This invention provides a two-stroke free piston engine, wherein the number of cylinder groups is one; each linear reciprocating motion of the piston corresponds to a first stroke and a second stroke, forming a working cycle; during the engine's cyclic operation, the piston pushes the push rod to perform a linear reciprocating motion together; in the first stroke, the push rod drives the rocker gear to rotate in a first direction via the rack, and the rocker gear is connected to the first power output component via a first one-way clutch to ensure that the first power output component transmits torque, and simultaneously the second one-way clutch disengages to ensure that the second power output component idles in the same direction as the rotation direction of the previous stroke; in the second stroke, the push rod drives the rocker gear to rotate in a second direction opposite to the first direction via the rack, and the rocker gear is connected to the second power output component via the second one-way clutch to ensure that the second power output component transmits torque, and simultaneously the first one-way clutch disengages to allow the first power output component to idle in the same direction as the rotation direction of the previous stroke; the first power output component and the second power output component alternately transmit and output engine torque, and their respective rotation directions remain unchanged.

[0010] In one embodiment, the transmission unit further includes a first coupling mechanism, through which the first power output component and the second power output component are connected, coupling the power output alternately from the two power output components into a single and continuous power output, and the direction of rotation remains unchanged.

[0011] In one embodiment, the rocker gear is directly driven to the first power output component via the first one-way clutch, and the rocker gear is directly driven to the second power output component via the second one-way clutch.

[0012] Furthermore, the first power output component and the second power output component are respectively an output shaft or an output wheel for outputting torque.

[0013] Furthermore, the rocker gear and / or the first power output component and / or the second power output component are connected by the first coupling mechanism to couple the power output of every two consecutive strokes and ensure continuous power output, while the power output direction remains unchanged.

[0014] Furthermore, the first coupling mechanism includes a coupling gear and a first output gear and a second output gear coaxially arranged; the first power output component includes a first output shaft lockably connected to the first one-way clutch and a first gear fixed to the first output shaft; the second power output component includes a second output shaft lockably connected to the second one-way clutch and a second gear fixed to the second output shaft; the first output gear is driven to connect to the first gear through the coupling gear, and the second output gear meshes with the second gear.

[0015] Furthermore, the first coupling mechanism includes a coupling gear and a first output gear and a second output gear arranged coaxially. Both the first power output component and the second power output component are gears. A first one-way clutch is provided between the shaft of the first power output component and the shaft of the rocker gear, and a second one-way clutch is provided between the shaft of the second power output component and the shaft of the rocker gear. The first output gear is driven to connect to the first power output component through the coupling gear, and the second output gear meshes with the second power output component.

[0016] Furthermore, the first coupling mechanism includes a transmission gear set, the shaft of the rocker gear is fixedly connected to the transmission gear set, the transmission gear set is driven to the first power output component through the first one-way clutch, and is driven to the second power output component through the second one-way clutch, thereby forming an indirect drive configuration.

[0017] Furthermore, the first power output component includes a first output shaft lockably connected to the first one-way clutch and a first gear fixed to the first output shaft; the second power output component includes a second output shaft lockably connected to the second one-way clutch and a second gear fixed to the second output shaft, wherein the first gear and the second gear mesh with each other.

[0018] Furthermore, the first coupling mechanism includes a coupling gear and a transmission gear set, the shaft of the rocking gear is fixedly connected to the transmission gear set, the first power output component is a gear, and the shaft of the rocking gear is directly driven to the first power output component through the first one-way clutch; the second power output component includes a second output shaft lockably connected to the second one-way clutch and a second gear fixed to the second output shaft, the transmission gear set is driven to the second output shaft through the second one-way clutch; the first power output component is driven to the second gear through the coupling gear.

[0019] This invention provides a four-stroke free piston engine. The cylinder bank consists of two groups, with the pistons of the two cylinders in each group connected by corresponding pushrods. Each pushrod has a rack, and a rocker gear meshes with the racks on the pushrods. Each cylinder sequentially completes the intake stroke, compression stroke, power stroke, and exhaust stroke. The system forms a working cycle every four strokes. In each stroke, one cylinder's piston performs the power stroke and simultaneously drives the other three cylinders to complete their intake, compression, and exhaust strokes through the combined action of the pushrods, racks, and rocker gears. In the first stroke, only one power piston drives the rocker gear to rotate in a first direction via the pushrod rack. In the second stroke, only one power piston drives the rocker gear to rotate in the opposite direction via the pushrod rack. The second stroke involves rotation in the first direction; the third stroke involves only one power piston driving the rocker gear to rotate in the first direction via the rack of the push rod; the fourth stroke involves only one power piston driving the rocker gear to rotate in the second direction via the rack of the push rod; when the rocker gear rotates in the first direction, the first one-way clutch engages, the rocker gear transmits torque and outputs power through the first power output component, and simultaneously the second one-way clutch disengages, the second power output component idling in the same direction as the rotation direction of the previous stroke; when the rocker gear rotates in the second direction, the first one-way clutch disengages, the first power output component idling in the same direction as the rotation direction of the previous stroke, and simultaneously the second one-way clutch engages, the rocker gear transmitting torque and outputting power through the second power output component.

[0020] In one embodiment, a second coupling mechanism is also included; the first power output member and the second power output member are coupled through the second coupling mechanism to output continuous power.

[0021] In one embodiment, one cylinder in one group generates a driving force during the power stroke to push its piston toward a first direction; and through the transmission unit, drives the piston of another cylinder in the same group to move toward the first direction to achieve the compression stroke, simultaneously driving the pistons of the third and fourth cylinders in another group to move toward a second direction opposite to the first direction, so that the third and fourth cylinders in the other group respectively complete the intake stroke and the exhaust stroke; or drives the piston of another cylinder in the same group to move toward the first direction to achieve the exhaust stroke, simultaneously driving the pistons of the third and fourth cylinders in another group to move toward a second direction opposite to the first direction, so that the third and fourth cylinders in the other group respectively complete the intake stroke and the compression stroke.

[0022] In one embodiment, the racks of the two push rods are single-sided racks and are arranged opposite to each other; the rocker gear is disposed between the racks of the two push rods.

[0023] In one embodiment, the two push rods are integrally connected and move synchronously in the same direction; the racks on the two push rods are located on the same side, and the rocker gear meshes with the racks on both push rods simultaneously.

[0024] In one embodiment, the gears of the two racks are connected one-to-one; or the gears of the two racks are independent of each other.

[0025] In one embodiment, the rocker gear is directly driven to the first power output component via the first one-way clutch, and the rocker gear is directly driven to the second power output component via the second one-way clutch.

[0026] Furthermore, the first power output component includes a first output shaft connected to the first one-way clutch and a first gear fixed to the first output shaft; the second power output component includes a second output shaft connected to the second one-way clutch and a second gear fixed to the second output shaft.

[0027] Furthermore, the second coupling mechanism includes a coupling gear and a first transmission gear and a second transmission gear arranged coaxially. The first transmission gear is driven to connect to the first gear through the coupling gear, and the second transmission gear is driven to connect to the second gear.

[0028] In one embodiment, both the first power output component and the second power output component are gears, a first one-way clutch is provided between the shaft of the first power output component and the shaft of the rocker gear, and a second one-way clutch is provided between the shaft of the second power output component and the shaft of the rocker gear.

[0029] Furthermore, the second coupling mechanism includes a coupling gear and a first transmission gear and a second transmission gear arranged coaxially. The first transmission gear is driven to connect to the first power output component through the coupling gear, and the second transmission gear is driven to connect to the second power output component.

[0030] In one embodiment, the transmission unit includes a transmission gear set; the shaft of the rocker gear is fixedly connected to the transmission gear set, and the transmission gear set is driven to the first power output component through the first one-way clutch and driven to the second power output component through the second one-way clutch, thereby forming an indirect drive configuration.

[0031] Furthermore, the first power output component includes a first output shaft connected to the first one-way clutch and a first gear fixed to the first output shaft; the second power output component includes a second output shaft connected to the second one-way clutch and a second gear fixed to the second output shaft, and the first gear and the second gear mesh with each other.

[0032] In one embodiment, the second coupling mechanism includes a coupling gear and a transmission gear set, the shaft of the rocking gear is fixedly connected to the transmission gear set, the first power output component is a first gear, and the shaft of the rocking gear is directly driven to the first gear through the first one-way clutch; the second power output component includes a second output shaft connected to the second one-way clutch and a second gear fixed to the second output shaft, the transmission gear set is driven to the second output shaft through the second one-way clutch; the first gear is driven to the second gear through the coupling gear.

[0033] The technical solution provided by this invention has the following beneficial effects:

[0034] This invention eliminates the complex transmission mechanism consisting of crankshafts and other components found in existing technologies, thereby reducing overall costs. Furthermore, by using a push rod with a rack to drive a single rocker gear to rotate on a fixed axis, it converts the linear reciprocating motion of the piston into rotary motion, outputting rotational power to drive a rotary generator with stable power generation efficiency. This improves the conversion efficiency from mechanical energy to electrical energy, while also increasing engine efficiency. It can also serve as a direct power source for driving HEV, PHEV, and REEV vehicles. Attached Figure Description

[0035] Figure 1 shows a partial schematic diagram of a free piston engine in Embodiment 1 with the second cylinder in the scavenging state.

[0036] Figure 2 shows a partial schematic diagram of a free piston engine in Embodiment 1, where the first cylinder is in the power stroke state.

[0037] Figure 3 shows a partial schematic diagram of a free piston engine in Embodiment 1 with the first cylinder in the scavenging state.

[0038] Figure 4 shows a partial schematic diagram of a free piston engine in Embodiment 1 with the second cylinder in the power stroke state.

[0039] Figure 5 shows a connection diagram of the free piston engine in Embodiment 1;

[0040] Figure 6 shows a connection diagram of the free piston engine in Embodiment 2;

[0041] Figure 7 shows a connection diagram of the free piston engine in Embodiment 3;

[0042] Figure 8 shows a connection diagram of the free piston engine in Embodiment 4;

[0043] Figure 9 shows a schematic diagram of the free piston engine in the first stroke of Embodiment 5;

[0044] Figure 10 shows a schematic diagram of the free piston engine in the second stroke of Embodiment 5;

[0045] Figure 11 shows a schematic diagram of the free piston engine in the third stroke of Embodiment 5;

[0046] Figure 12 shows a schematic diagram of the free piston engine in the fourth stroke of Embodiment 5;

[0047] Figure 13 shows a connection diagram of the free piston engine in Embodiment 5;

[0048] Figure 14 shows a connection diagram of the free piston engine in Embodiment 6;

[0049] Figure 15 shows a connection diagram of the free piston engine in Embodiment 7;

[0050] Figure 16 shows a connection diagram of the free piston engine in Embodiment 8. Detailed Implementation

[0051] To further illustrate the various embodiments, the present invention provides accompanying drawings. These drawings are part of the disclosure of the present invention, primarily used to illustrate the embodiments and to explain the operating principles of the embodiments in conjunction with the relevant descriptions in the specification. With reference to these drawings, those skilled in the art should be able to understand other possible implementations and the advantages of the present invention. Components in the drawings are not drawn to scale, and similar component symbols are generally used to represent similar components.

[0052] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0053] Example 1

[0054] Referring to Figures 1 to 5, Embodiment 1 provides a free piston engine (hereinafter referred to as a piston engine). The piston engine of this embodiment includes two cylinders arranged opposite to each other, namely a first cylinder 1a and a second cylinder 1b, and the pistons of the first cylinder 1a and the second cylinder 1b are the first piston 2a and the second piston 2b, respectively.

[0055] The piston engine also includes a transmission unit, as shown in Figure 5. This transmission unit includes a rocker gear 4, a first one-way clutch 5a, a second one-way clutch 5b, a first power output component 6a, a second power output component 6b, and a first coupling mechanism 100. The first power output component 6a engages with the first one-way clutch 5a, and the second power output component 6b engages with the second one-way clutch 5b. Both the first and second power output components 6a and 6b are used to transmit engine torque. The first coupling mechanism 100 is a downstream component of both power output components.

[0056] As shown in Figures 2 and 4, the first piston 2a of the first cylinder 1a and the second piston 2b of the second cylinder 1b are connected by a push rod 3, and the push rod 3 is provided with a rack. The rocker gear 4 meshes with the rack 31 on the push rod 3, and the rocker gear 4 is set to rotate around a fixed axis so that the rocker gear 4 can rock around its own axis.

[0057] Each time the piston makes a linear reciprocating motion, it forms the first stroke and the second stroke in sequence. In each stroke, one cylinder is always doing power and another cylinder is compressing, so as to ensure that power is output in each stroke and can proceed to the next stroke. Therefore, this piston engine is a two-stroke free piston engine.

[0058] During the first stroke, the rocker gear 4 is connected to the first power output component 6a via the first one-way clutch 5a to ensure that the first power output component 6a transmits torque, and simultaneously the second one-way clutch 5b disengages to ensure that the second power output component 6b rotates in the same direction as the rotation direction of the previous stroke.

[0059] During the second stroke, the rocker gear 4 is connected to the second power output component 6b via the second one-way clutch 5b to ensure that the second power output component 6b transmits torque, and simultaneously the first one-way clutch 5a disengages so that the first power output component 6a rotates in the same direction as the rotation direction of the previous stroke.

[0060] In this embodiment, the push rod 3 is a linear rod structure. The piston moves from one end of the cylinder to the other end of the cylinder in one stroke. One round trip is one round trip, and two strokes constitute one working cycle.

[0061] First, as shown in Figure 1, at the end of the stroke of the previous working cycle, the first piston 2a of the first cylinder 1a moves to the leftmost end of the first cylinder 1a, and the air-fuel mixture in the first cylinder 1a is compressed. The second cylinder 1b completes scavenging, blowing out the exhaust gas and blowing in the air-fuel mixture. Next, as shown in Figure 2, when combustion occurs in the first cylinder 1a, the first cylinder 1a is in the power stroke. The pressure in the first cylinder 1a increases, pushing the first piston 2a to the right. This pushes the second piston 2b to the right via the push rod 3, compressing the air-fuel mixture in the second cylinder 1b. The second cylinder 1b is in the compression stroke, and at this time, both pistons move synchronously to the right in a straight line to form the first stroke.

[0062] Then, as shown in Figure 3, when the second piston 2b of the second cylinder 1b moves to the rightmost end of the second cylinder 1b, the compression stroke ends. The first cylinder 1a performs scavenging, blowing out the exhaust gas and blowing in the air-fuel mixture; the air-fuel mixture in the second cylinder 1b is compressed. Finally, as shown in Figure 4, when combustion occurs in the second cylinder 1b, the second cylinder 1b enters the power stroke. The pressure in the second cylinder 1b increases, pushing the second piston 2b to the left, and through the push rod 3, pushing the first piston 2a to the left, compressing the air-fuel mixture in the first cylinder 1a. The first cylinder 1a is in the compression stroke, and at this time, both pistons move synchronously to the left in a straight line to form the second stroke. Then, the next working cycle begins.

[0063] Therefore, one reciprocating linear motion of the piston forms a working cycle, and the next working cycle begins immediately after the first working cycle is completed.

[0064] When the piston and push rod 3 reciprocate in the left and right directions, the rack 31 on the push rod 3 drives the rocker gear 4 to rotate. During the first stroke, the rack 31 moving to the right drives the rocker gear 4 to rotate clockwise. During the second stroke, the rack 31 moving to the left drives the rocker gear 4 to rotate counterclockwise. This achieves the transformation of the piston's reciprocating linear motion into the fixed-axis rocker rotation of the rocker gear 4 through the meshing transmission between the rack 31 on the push rod 3 and the rocker gear 4.

[0065] As shown in Figure 5, the rocker gear 4 rotates on a fixed axis and can rock around its own axis. The rocker gear 4 is connected to the first power output component 6a through the first one-way clutch 5a, or to the second power output component 6b through the second one-way clutch 5b. Since the locking directions of the first one-way clutch 5a and the second one-way clutch 5b are set to be opposite to each other, when the rocker gear 4 rotates, one power output component is always in transmission and the other is idling. This ensures that the two power output components alternately transmit torque and idle in the two strokes of one cycle of the piston engine. The rotation direction of each power output component remains unchanged. In addition, the two power output components can output power independently and are each connected to a load (such as a generator).

[0066] The first one-way clutch 5a locks during the first stroke, and the clockwise rotating rocker gear 4 drives the first power output member 6a to rotate clockwise and transmit power through the first one-way clutch 5a; then the first one-way clutch 5a disengages during the second stroke, so that the rocker gear 4, which has rotated counterclockwise, is separated from the first power output member 6a, and the first power output member 6a can continue to rotate clockwise without load.

[0067] Synchronously, the second one-way clutch 5b disengages during the first stroke, causing the clockwise rotating rocker gear 4 to separate from the second power output member 6b, which then rotates counterclockwise under no load. Next, the second one-way clutch 5b locks during the second stroke, causing the counterclockwise rotating rocker gear 4 to drive the second power output member 6b to rotate counterclockwise and transmit torque through the second one-way clutch 5b.

[0068] In summary, the first power output component 6a rotates and outputs torque during the first stroke, but idles during the second stroke while maintaining its rotation direction. The second power output component 6b idles during the first stroke, but outputs torque during the second stroke while maintaining its rotation direction.

[0069] More specifically, as shown in Figure 5, the first coupling mechanism 100 includes a coupling gear 8 and a first output gear 10 and a second output gear 9 arranged coaxially. The first power output component 6a and the second power output component 6b are connected through the first coupling mechanism 100 to couple the power output of every two consecutive strokes and ensure continuous power output. The power output direction remains unchanged, that is, the piston engine has only one power output and can continuously output power. To achieve this, the two power output components need to be coupled together.

[0070] More specifically, the first power output component 6a includes a first output shaft 61 lockably connected to the first one-way clutch 5a and a first gear 62 fixed to the first output shaft 61; the second power output component 6b includes a second output shaft 63 lockably connected to the second one-way clutch 5b and a second gear 64 fixed to the second output shaft 63, the first output gear 10 drives the first gear 62 connected to the first power output component 6a through the coupling gear 8, and the second output gear 9 meshes with the second gear 64 of the second power output component 6b.

[0071] In addition, in this specific embodiment, the first output shaft 61 and the first gear 62 of the first power output component 6a are fixedly connected and rotate in the same direction. The first gear 62 of the first power output component 6a meshes with the coupling gear 8 and rotates in opposite directions, and the coupling gear 8 meshes with the first output gear 10 and rotates in opposite directions.

[0072] The second output shaft 63 and the second gear 64 of the second power output component 6b are fixedly connected and rotate in the same direction. The second gear 64 of the second power output component 6b meshes with the second output gear 9, but they rotate in opposite directions.

[0073] The first output gear 10 and the second output gear 9 are coaxially fixedly connected via shaft 91 to achieve rotation in the same direction.

[0074] During the first stroke, the push rod 3, moving to the right, drives the rocker gear 4 to rotate clockwise, locking the first one-way clutch 5a. The rocker gear 4 drives the first power output component 6a to rotate clockwise through the first one-way clutch 5a. The first gear 62 of the first power output component 6a drives the coupling gear 8 to rotate counterclockwise. The coupling gear 8 drives the first output gear 10 and the second output gear 9 to rotate clockwise together and transmit power. At the same time, the second one-way clutch 5b disengages, and the second output shaft 63 of the second power output component 6b can rotate counterclockwise without constraint. The clockwise rotating second output gear 9 drives the second power output component 6b to rotate counterclockwise.

[0075] During the second stroke, the push rod 3, moving to the left, drives the rocker gear 4 to rotate counterclockwise, locking the second one-way clutch 5b. The rocker gear 4, through the second one-way clutch 5b, drives the second power output component 6b to rotate counterclockwise. The second gear 64 of the second power output component 6b drives the second output gear 9 and the first output gear 10 to rotate clockwise together and transmit power. The first output gear 10 drives the coupling gear 8 to rotate counterclockwise. At the same time, the first one-way clutch 5a disengages, and the first output shaft 61 can rotate clockwise without constraint. That is, the first output gear 10 drives the coupling gear 8 to rotate counterclockwise, and the coupling gear 8 drives the first power output component 6a to rotate clockwise together.

[0076] Therefore, during the first stroke, the rocker gear 4 drives the first output component 6a to rotate clockwise via the first one-way clutch 5a. The first output component drives the coupling gear 8 to rotate counterclockwise. The coupling gear 8 drives the first output gear 10 to rotate clockwise. The second output gear 9, which is coaxially fixed to the first output gear 10, drives the second output component 6b to rotate counterclockwise. The shaft 91 of the second output gear 9 and the first output gear 10 rotates clockwise and outputs power. During the second stroke, the rocker gear 4 drives the first output component 6b to rotate counterclockwise via the second one-way clutch 5b. The second output component 6b drives the second output gear 9 to rotate clockwise. The first output gear 10, which is coaxially fixed to the second output gear 9, drives the coupling gear 8 to rotate counterclockwise. The coupling gear 8 drives the first output component 6a to rotate clockwise. The shaft 91 of the second output gear 9 and the first output gear 10 rotates clockwise and outputs power.

[0077] In other words, the shaft 91 of the second output gear 9 and the first output gear 10 is continuously driven to rotate clockwise, with its rotation direction remaining unchanged or its power output direction remaining unchanged, thus achieving power coupling between the two power output components. Simultaneously, whether in transmission or idling, the rotation direction of all gears and shafts downstream of the two one-way clutches remains unchanged. Specifically, the first output component 6a, the second output gear 9, and the first output gear 10 rotate clockwise, while the second output component 6b and the coupling gear 8 rotate counterclockwise. Through power coupling, any shaft and gear downstream of the two one-way clutches—namely, the first output component 6a, the second output component 6b, the coupling gear 8, the second output gear 9, and the first output gear 10—can serve as the total output.

[0078] In one working cycle of the piston engine in this embodiment, the piston engine has a variable stroke and compression ratio. The variable compression ratio allows the use of different fuels to improve the flexibility and adaptability of the piston engine, promotes HCCI combustion to ensure higher thermal efficiency, and can also improve the potential for SI-HCCI conversion through the variable compression ratio.

[0079] This embodiment replaces the complex transmission mechanism composed of crankshaft and other components in the prior art with a push rod 3 equipped with rack 31 and a transmission unit. This not only reduces the number of moving parts, simplifies the transmission structure, and reduces the overall cost, but also eliminates the need for high-pressure oil-lubricated bearings, thereby eliminating the need for an oil pump, thus reducing energy consumption and improving the system's energy conversion efficiency. It also effectively reduces the lateral load on the engine piston, thereby reducing the friction loss between the piston and the cylinder wall.

[0080] Furthermore, by driving a single rocker gear 4 to rotate through the rack 31 on the push rod 3, the linear reciprocating motion of the piston of the piston engine is converted into rotational motion, so as to output rotational power to drive a rotary generator with stable power generation efficiency, thereby improving the conversion efficiency of mechanical energy into electrical energy. At the same time, it can also improve engine efficiency and can be used as direct power to drive vehicles such as HEV, PHEV and REEV.

[0081] Of course, in other embodiments, if the transmission unit adopts a double rocker gear design, the two rocker gears need to withstand the huge thrust output by the piston during operation, and the load fluctuates greatly. The technical requirements for the gears, gear shafts, and bearings are high, and the cost is also high. Arranging two rocker gears between the two cylinders requires more space, and the stiffness of the push rod 3 needs to be enhanced. However, this embodiment uses a transmission unit with a single rocker gear, which can reduce costs, reduce size and weight, and improve design flexibility.

[0082] In addition, when the piston of the piston engine is around the top dead center, its acceleration is significantly higher, thereby reducing the residence time at high temperature and reducing heat transfer loss during combustion. When the piston of the piston engine is around the bottom dead center, the lever arm of push rod 3 does not decrease, and the output power decays less, so as to achieve small output power fluctuation.

[0083] Compared to existing piston engines, which exhibit strong vibrations in the x, y, and z axes, the piston engine in this embodiment only experiences strong vibrations in one direction (i.e., the piston moves along the left and right directions), resulting in a significant improvement in NVH (noise, vibration, and acoustic roughness) characteristics.

[0084] Example 2

[0085] As shown in Figure 6, Embodiment 2 provides a free piston engine. Embodiment 2 is largely the same in structure as Embodiment 1, except that both the first power output component 6a' and the second power output component 6b' are gears. A first one-way clutch 5a is provided between the first power output component 6a' and the shaft 41 of the rocker gear 4, and a second one-way clutch 5b is provided between the second power output component 6b' and the shaft 41 of the rocker gear 4. The two power output components alternately transmit torque and perform corresponding idling within two strokes of one cycle of the piston engine. The rotation direction of each power output component remains unchanged. Furthermore, the two power output components can output power independently and are each connected to a load (such as a generator). Of course, the movement of the push rod, rocker gear 4, and two cylinders in Embodiment 2 is as shown in Figures 1 to 4 of Embodiment 1, and therefore will not be described in detail here.

[0086] In this specific embodiment, the first one-way clutch 5a is arranged between the shaft 41 of the rocker gear 4 and the first power output member 6a', and the second one-way clutch 5b is arranged between the shaft 41 of the rocker gear 4 and the second power output member 6b'. The first power output member 6a' meshes with the coupling gear 8 and rotates in opposite directions; the coupling gear 8 meshes with the first output gear 10 and rotates in opposite directions; the second power output member 6b' meshes with the second output gear 9 and rotates in opposite directions.

[0087] During the first stroke, the rocker gear 4 rotates clockwise, the first one-way clutch 5a locks, and the rocker gear 4 drives the first power output component 6a' to rotate clockwise through the first one-way clutch 5a. The first power output component 6a' drives the coupling gear 8 to rotate counterclockwise and transmit power. The coupling gear 8 drives the first output gear 10 and the second output gear 9 to rotate clockwise together and transmit power. At the same time, the second one-way clutch 5b disengages, and the second power output component 6b' can rotate freely without restraint. The clockwise rotating second output gear 9 drives the second power output component 6b' to rotate counterclockwise.

[0088] During the second stroke, the rocker gear 4 rotates counterclockwise, the second one-way clutch 5b locks, and the rocker gear 4 drives the second power output component 6b' to rotate counterclockwise through the second one-way clutch 5b. The second power output component 6b' drives the second output gear 9 and the first output gear 10 to rotate clockwise together and transmit power. At this time, the first output gear 10 drives the coupling gear 8 to rotate counterclockwise. At the same time, the first one-way clutch 5a disengages, and the first power output component 6a' can rotate freely without restraint. The first power output component 6a' rotates clockwise freely because the counterclockwise rotating coupling gear 8 drives the first power output component 6a' to rotate freely.

[0089] In summary, during the first stroke, the shafts 91 of the second output gear 9 and the first output gear 10 are driven to rotate clockwise; during the second stroke, the shafts 91 of the second output gear 9 and the first output gear 10 are driven to rotate clockwise. That is to say, the shafts 91 of the second output gear 9 and the first output gear 10 are continuously driven to rotate clockwise, and their rotation direction remains unchanged or the power output direction remains unchanged, thus achieving power coupling between the two power output components. After power coupling, any shaft and gear downstream of the two one-way clutches, namely the first power output component 6a', the second power output component 6b', the coupling gear 8, the second output gear 9, and the first output gear 10, can all serve as the main output shaft.

[0090] Example 3

[0091] As shown in Figure 7, Embodiment 3 provides a free piston engine. Embodiment 3 and Embodiment 1 have largely the same structure, except that the first coupling mechanism 100' further includes a transmission gear set 200, comprising gear A, gear B, and gear C. Gear A is fixedly mounted on the shaft 41 of the rocker gear 4. Gear A meshes with gear B and gear C respectively. Gear B is driven to connect to the first power output component 6a via a first one-way clutch 5a, and gear C is driven to connect to the second power output component 6b via a second one-way clutch 5b, thus forming an indirect drive configuration. The two power output components alternately transmit torque and perform corresponding idling within two strokes of one cycle of the piston engine, and the rotation direction of each power output component remains unchanged. Furthermore, the two power output components can independently output power and are each connected to a load (such as a generator). Of course, the movement of the push rod, rocker gear 4, and two cylinders in Embodiment 3 is as shown in Figures 1 to 4 of Embodiment 1, and therefore will not be described in detail here.

[0092] In this specific embodiment, the first power output component 6a includes a first output shaft 61 lockably connected to the first one-way clutch 5a and a first gear 62 fixed to the first output shaft 61; the second power output component 6b includes a second output shaft 63 lockably connected to the second one-way clutch 5b and a second gear 64 fixed to the second output shaft 63, and the first gear 62 of the first power output component 6a and the second gear 64 of the second power output component 6b mesh with each other.

[0093] The rocker gear 4 is driven to connect with the first output shaft 61 of the first power output member 6a through gear A, gear B and the first one-way clutch 5a to form the first torque transmission route.

[0094] The rocker gear 4 is driven to connect with the second output shaft 63 of the second power output component 6b via gear A, gear C and the second one-way clutch 5b to form a second torque transmission path.

[0095] During the first stroke, the push rod drives the rocker gear 4 and gear A to rotate clockwise together. Gear A drives gears B and C to rotate counterclockwise simultaneously. The first one-way clutch 5a is locked. Gear B drives the first power output component 6a to rotate counterclockwise through the first one-way clutch 5a. At the same time, the second one-way clutch 5b is disengaged, and the second power output component 6b can rotate clockwise without restraint. The first gear 62 of the first power output component 6a drives the second power output component 6b to rotate clockwise.

[0096] During the second stroke, the push rod drives the rocker gear 4 and gear A to rotate counterclockwise, and gear A drives gears B and C to rotate clockwise simultaneously. The second one-way clutch 5b is locked, and gear C drives the second power output component 6b to rotate clockwise through the second one-way clutch 5b. At the same time, the first one-way clutch 5a is disengaged, and the first power output component 6a can rotate freely without restraint. The second gear 64 drives the first power output component 6a to rotate counterclockwise.

[0097] In summary, during the first stroke, the second output shaft 63 of the second power output component 6b is driven to rotate clockwise; during the second stroke, the second power output component 6b is still driven to rotate clockwise. That is, the second power output component 6b is continuously driven to rotate clockwise, with its rotation direction remaining unchanged or its power output direction remaining unchanged, thus coupling the power of the two power output components. Similarly, the first output shaft 61 of the first power output component 6a is continuously driven to rotate counterclockwise; and after power coupling, any shaft and gear downstream of the two one-way clutches, i.e., the first power output component 6a and the second power output component 6b, can serve as the main output shaft to achieve alternating operation of the two continuous strokes, and the rocker gear 4 can also continuously rock and rotate.

[0098] Example 4

[0099] As shown in Figure 8, Embodiment 4 provides a free piston engine. The structure of Embodiment 4 is largely the same as that of Embodiment 3, except that: the transmission gear set 200' in this embodiment includes gear D and gear E, wherein gear D is fixed on the shaft 41 of the rocker gear 4, and gear D meshes with gear E. The first power output component 6a' is the first gear, and the shaft 41 of the rocker gear 4 is directly driven to the first power output component 6a' through the first one-way clutch 5a; the second power output component 6b includes a second output shaft 63 that can be locked to the second one-way clutch 5b and a second gear 64 fixed to the second output shaft 63. Gear E is driven to the second output shaft 63 of the second power output component 6b through the second one-way clutch 5b; moreover, the second output shaft 63 and the second gear 64 are coaxially fixedly connected, and the first power output component 6a' is driven to the second gear 64 of the second power output component 6b through the coupling gear 8 to achieve power coupling. The two power output components alternately transmit torque and idle within two strokes of one cycle of the piston engine, and the rotation direction of each power output component remains unchanged. Furthermore, each power output component can output power independently and is connected to a load (such as a generator). Of course, the movement of the push rod, rocker gear 4, and the two cylinders in Embodiment 4 is as shown in Figures 1 to 4 of Embodiment 1, and therefore will not be described in detail here.

[0100] During the first stroke, the first cylinder performs work, and the push rod drives the rocker gear 4 and gear D to rotate clockwise. Gear D drives gear E to rotate counterclockwise. The first one-way clutch 5a locks, and the rocker gear 4 drives the first power output component 6a' to rotate clockwise through the first one-way clutch 5a. The first power output component 6a' drives the coupling gear 8 to rotate counterclockwise and transmits power. At the same time, the second one-way clutch 5b disengages. Since the second power output component 6b can rotate freely without restraint, the coupling gear 8 drives the second power output component 6b to rotate clockwise.

[0101] It can be seen that the torque transmission route of the first stroke is as follows: the rocker gear 4, the first power output component 6a' and the coupling gear 8 transmit power in sequence.

[0102] During the second stroke, when the second cylinder is working, the push rod drives the rocker gear 4 and gear D to rotate counterclockwise. Gear D drives gear E to rotate clockwise. The second one-way clutch 5b is locked. Gear E drives the second power output component 6b to rotate clockwise through the second one-way clutch 5b. The second gear 64 of the second power output component 6b drives the coupling gear 8 to rotate counterclockwise and transmits power. At the same time, the first one-way clutch 5a is disengaged. Since the first power output component 6a' can rotate freely without restraint, the coupling gear 8 drives the first power output component 6a' to rotate clockwise freely.

[0103] As can be seen, the torque transmission route of the second stroke is as follows: the rocker gear 4, gear D, gear E, second power output component 6b and coupling gear 8 transmit power in sequence.

[0104] During the first stroke, the coupling gear 8 is driven to rotate counterclockwise; during the second stroke, the coupling gear 8 is still driven to rotate counterclockwise. That is, the coupling gear 8 is continuously driven to rotate counterclockwise, with its rotation direction remaining unchanged or its power output direction remaining unchanged, thus coupling the power of the two power output components. Through the coupling connection of the coupling gear 8, any shaft and gear downstream of the two one-way clutches, the first power output component 6a', the second power output component 6b, and the coupling gear 8 can all serve as the main output shaft, ensuring their respective rotation directions and continuously outputting power.

[0105] Example 5

[0106] Referring to Figures 9 to 13, Embodiment 5 provides a free piston engine (hereinafter referred to as a piston engine). The piston engine includes two sets of cylinders, each set of cylinders including two cylinders arranged opposite each other, and also includes a transmission unit. As shown in Figure 13, the transmission unit includes a rocker gear 4, a first one-way clutch 5a, a second one-way clutch 5b, a first power output component, and a second power output component. The first power output component is engaged with the first one-way clutch 5a, and the second power output component is engaged with the second one-way clutch 5b. Both the first power output component and the second power output component are used to transmit engine torque. The rocker gear 4 is configured to rotate around a fixed axis, so that the rocker gear 4 can rock around its own axis.

[0107] The four cylinders are divided into two groups. The pistons of the two cylinders in each group are connected by a push rod. Each push rod is equipped with a rack, and the rocker gear 4 meshes with the racks on the two push rods.

[0108] Each cylinder sequentially completes the intake stroke, compression stroke, power stroke, and exhaust stroke. The system (i.e., the piston engine) forms a working cycle every four strokes, and in each stroke, the piston of one cylinder is always doing power, and synchronously drives the other three cylinders to complete the intake stroke, compression stroke, and exhaust stroke respectively. Therefore, this piston engine is a four-stroke free piston engine.

[0109] In this embodiment, the racks on the two push rods are single-sided racks and are arranged opposite to each other, and the rocker gear 4 is arranged between the racks of the two push rods.

[0110] The two sets of cylinders are located on the upper and lower sides of the rocker gear 4, respectively. The two cylinders in the upper cylinder set are the first cylinder 1a' and the second cylinder 1b', which are spaced to the left and right. The two cylinders in the lower cylinder set are the third cylinder 1c and the fourth cylinder 1d, which are spaced to the left and right. Specifically, the first cylinder 1a', the second cylinder 1b', the third cylinder 1c, and the fourth cylinder 1d are all fixedly mounted on the housing of the piston engine and are stationary.

[0111] The first cylinder 1a' is equipped with a first piston 2a', the second cylinder 1b' is equipped with a second piston 2b', the third cylinder 1c is equipped with a third piston 2c, and the fourth cylinder 1d is equipped with a fourth piston 2d. The two push rods are the first push rod and the second push rod, and the racks of the first push rod and the second push rod are the first rack 3a and the second rack 3b, respectively.

[0112] The first piston 2a' and the second piston 2b' are fixedly connected by the first push rod, so that the first piston 2a', the second piston 2b' and the first push rod can move together in a left-right reciprocating linear motion. The third piston 2c and the fourth piston 2d are fixedly connected by the second push rod, so that the third piston 2c, the fourth piston 2d and the second push rod can move together in a left-right reciprocating linear motion. At this time, the first direction is defined as the horizontal rightward direction of the first push rod, the second direction is defined as the horizontal leftward direction of the first push rod, the first rotation direction is the clockwise rotation direction, and the second rotation direction is the counterclockwise rotation direction.

[0113] The specific working principle of the piston engine in this embodiment is as follows, including the first stroke as shown in Figure 9, the second stroke as shown in Figure 10, the third stroke as shown in Figure 11, and the fourth stroke as shown in Figure 12.

[0114] As shown in Figure 9, during the first stroke, when the first cylinder 1a' is in the intake stroke, the driving force comes from the third piston 2c of the third cylinder 1c. This means the fuel in the third cylinder 1c burns and expands, performing work; this is the power stroke. The high-pressure gas pushes the third piston 2c to the left, which in turn pushes the second push rod and the second rack 3b to the left, thereby driving the rocker gear 4 to rotate clockwise, which in turn drives the first push rod and the first rack 3a to the right. Simultaneously, the first push rod drives the first piston 2a' to the right, increasing the volume of the first cylinder 1a' and drawing in gas (such as air); this is the intake stroke. The first push rod pushes the second piston 2b' to the right, expelling the exhaust gas from the second cylinder 1b'; this is the exhaust stroke. The second push rod pushes the fourth piston 2d to the left, compressing the gas in the fourth cylinder 1d; this is the compression stroke.

[0115] In the first stroke, the first cylinder 1a' is the intake stroke, the second cylinder 1b' is the exhaust stroke, the third cylinder 1c is the power stroke, and the fourth cylinder 1d is the compression stroke. When the third cylinder 1c is doing power, the third piston 2c pushes the second rack 3b of the second push rod to move to the left, thereby driving the rocker gear 4 to rotate clockwise.

[0116] As shown in Figure 10, during the second stroke, when the first cylinder 1a' is in the compression stroke, the driving force comes from the fourth piston 2d of the fourth cylinder 1d. This means the fuel in the fourth cylinder 1d burns and expands to do work; this is the power stroke. The high-pressure gas pushes the fourth piston 2d to the right, which in turn pushes the second push rod and the second rack 3b to the right, thereby driving the rocker gear 4 to rotate counterclockwise, which in turn drives the first push rod and the first rack 3a to the left. Simultaneously, the first push rod drives the first piston 2a' to the left, compressing the gas in the first cylinder 1a'; this is the compression stroke. The first push rod and the first rack 3a drive the second piston 2b' to the left, increasing the volume in the second cylinder 1b' and drawing in gas; this is the intake stroke. The second push rod drives the third piston 2c to the right, discharging the exhaust gas from the third cylinder 1c; this is the exhaust stroke.

[0117] In the second stroke, the first cylinder 1a' is the compression stroke, the second cylinder 1b' is the intake stroke, the third cylinder 1c is the exhaust stroke, and the fourth cylinder 1d is the power stroke. When the fourth cylinder 1d is performing power, the fourth piston 2d pushes the second rack 3b of the second push rod to move to the right, thereby driving the rocker gear 4 to rotate counterclockwise.

[0118] As shown in Figure 11, during the third stroke, when the first cylinder 1a' is in the power stroke, the driving force comes from the first piston 2a' of the first cylinder 1a'. That is, the fuel in the first cylinder 1a' burns and expands to do work, which is the power stroke. The high-pressure gas pushes the first piston 2a' to the right, which in turn pushes the first push rod and the first rack 3a to the right, thereby driving the rocker gear 4 to rotate clockwise, which in turn drives the second push rod and the second rack 3b to the left. Simultaneously, the first push rod drives the second piston 2b' to the right, compressing the gas in the second cylinder 1b', which is the compression stroke. The second push rod drives the third piston 2c to the left, increasing the volume in the third cylinder 1c and drawing in gas, which is the intake stroke. The second push rod drives the fourth piston 2d to the left, expelling the exhaust gas from the fourth cylinder 1d, which is the exhaust stroke.

[0119] In the third stroke, the first cylinder 1a' is the power stroke, the second cylinder 1b' is the compression stroke, the third cylinder 1c is the intake stroke, and the fourth cylinder 1d is the exhaust stroke. When the first cylinder 1a' is doing power, the first piston 2a' pushes the first rack 3a of the first push rod to move to the right, thereby driving the rocker gear 4 to rotate clockwise.

[0120] As shown in Figure 12, during the fourth stroke, when the first cylinder 1a' is in the exhaust stroke, the driving force comes from the second piston 2b' of the second cylinder 1b'. This means the fuel in the second cylinder 1b' burns and expands to do work; this is the power stroke. The high-pressure gas pushes the second piston 2b' to the left, which in turn pushes the first push rod and its rack 3a to the left, driving the rocker gear 4 to rotate counterclockwise, which in turn drives the second push rod and its rack 3b to the right. Simultaneously, the first push rod drives the first piston 2a' to the left, expelling the exhaust gas from the first cylinder 1a'; this is the exhaust stroke. The second push rod drives the third piston 2c to the right, compressing the gas in the third cylinder 2c; this is the compression stroke. The second push rod drives the fourth piston 2d to the right, increasing the volume of the second cylinder 1b' and drawing in gas; this is the intake stroke.

[0121] In the fourth stroke, the first cylinder 1a' is in the exhaust stroke, the second cylinder 1b' is in the power stroke, the third cylinder 1c is in the compression stroke, and the fourth cylinder 1d is in the intake stroke. When the second cylinder 1b' is in power stroke, the second piston 2b' pushes the first push rod and its rack 3a to the left, thereby driving the rocker gear 4 to rotate counterclockwise.

[0122] In summary, a working cycle of a four-stroke piston engine consists of four strokes. In these four strokes, the first cylinder 1a' sequentially performs intake, compression, power, and exhaust; the second cylinder 1b' sequentially performs exhaust, intake, compression, and power; the third cylinder 1c sequentially performs power, exhaust, intake, and compression; and the fourth cylinder 1d sequentially performs compression, power, exhaust, and intake. In the first stroke, cylinder 1a' is for intake, cylinder 1b' is for exhaust, cylinder 1c is for power, and cylinder 1d is for compression; in the second stroke, cylinder 1a' is for compression, cylinder 1b' is for intake, cylinder 1c is for exhaust, and cylinder 1d is for power; in the third stroke, cylinder 1a' is for power, cylinder 1b' is for compression, cylinder 1c is for intake, and cylinder 1d is for exhaust; in the fourth stroke, cylinder 1a' is for exhaust, cylinder 1b' is for power, cylinder 1c is for compression, and cylinder 1d is for intake.

[0123] A piston engine completes one working cycle, consisting of four strokes, with the pushrod completing two reciprocating linear movements. Correspondingly, the rocker gear 4 completes two rocker rotations: in the first stroke, the piston drives the rocker gear 4 to rotate clockwise; in the second stroke, the piston drives the rocker gear 4 to rotate counterclockwise; in the third stroke, the piston drives the rocker gear 4 to rotate clockwise, and the behavior and function of the rocker gear 4 and its downstream components are the same as in the first stroke; in the fourth stroke, the piston drives the rocker gear 4 to rotate counterclockwise, and the behavior and function of the rocker gear 4 and its downstream components are the same as in the second stroke. Therefore, the working principles of the third and fourth strokes will not be described in detail.

[0124] The first stroke is the clockwise stroke of the rocker gear 4 rocking clockwise, and the second stroke corresponds to the counterclockwise stroke of the rocker gear 4 rocking counterclockwise. The rocker gear 4 first rotates clockwise, then counterclockwise, then clockwise again, and then counterclockwise again, repeating this back-and-forth rotation continuously.

[0125] The following describes how to convert the rocking rotation of the rocking gear 4 into a rotational motion with constant direction and alternating transmission and idling.

[0126] The locking directions of the first one-way clutch 5a and the second one-way clutch 5b are set to be opposite to each other. That is, when the rocker gear 4 rotates clockwise, the first one-way clutch 5a is locked and the second one-way clutch 5b is disengaged; when the rocker gear 4 rotates counterclockwise, the first one-way clutch 5a is disengaged and the second one-way clutch 5b is locked. In this way, regardless of whether the rocker gear 4 rotates clockwise or counterclockwise, there is always one power output component in transmission and the other power output component idling, so as to ensure that the two power output components alternately transmit torque and idle accordingly in each stroke stage of the piston engine, and the rotation direction of each power output component remains unchanged.

[0127] When the rocker gear 4 rotates clockwise, the first one-way clutch 5a locks, and the rocker gear 4 drives the first power output component to rotate and transmit power through the first one-way clutch 5a. Next, when the rocker gear 4 rotates counterclockwise, the first one-way clutch 5a disengages, separating the counterclockwise rotating rocker gear 4 from the first power output component, allowing the first power output component to continue rotating without load and maintaining its rotation direction. Simultaneously, when the rocker gear 4 rotates clockwise, the second one-way clutch 5b disengages, separating the rocker gear 4 from the second power output component, allowing the second power output component to rotate without load and maintain its rotation direction. Next, when the rocker gear 4 rotates counterclockwise, the second one-way clutch 5b locks, and the rocker gear 4 drives the second power output component to rotate and transmit torque through the second one-way clutch 5b.

[0128] In summary, when the rocker gear 4 rotates clockwise, it drives the first output component to rotate and transmit power through the first one-way clutch 5a, while the second one-way clutch 5b disconnects the connection between the rocker gear 4 and the second output component, thus allowing the second output component to idle in its original direction. When the rocker gear 4 rotates counterclockwise, it outputs power through the second one-way clutch 5b and the second output component, while the first one-way clutch 5a disconnects the connection between the rocker gear 4 and the first output component, thus allowing the first output component to idle in its original direction.

[0129] In another preferred embodiment, as shown in FIG13, the rocker gear 4 is directly driven to the first power output component via the first one-way clutch 5a, and the rocker gear 4 is directly driven to the second power output component via the second one-way clutch 5b.

[0130] Of course, in other embodiments, the drive assembly consisting of the rocker gear 4, two push rods and two cylinder groups in this embodiment can be replaced with other drive components containing a driver to provide a power source; other transmission units can also be used to replace the rocker gear 4 in this embodiment to achieve transmission connection.

[0131] More specifically, the piston engine in this embodiment further includes a second coupling mechanism 300, which includes a coupling gear 8' and a first transmission gear 10' and a second transmission gear 9' coaxially arranged; the first power output component includes a first output shaft 6a' connected to a first one-way clutch 5a and a first gear 7a fixed to the first output shaft 6a'; the second power output component includes a second output shaft 6b' connected to a second one-way clutch 5b and a second gear 7b fixed to the second output shaft 6b'; the first transmission gear 10' drives the first gear 7a connected to the first power output component through the coupling gear 8', and the second transmission gear 9' drives the second gear 7b connected to the second power output component, wherein the coupling gear 8' meshes with the first gear 7a of the first power output component, the coupling gear 8' meshes with the first transmission gear 10', the second transmission gear 9' meshes with the second gear 7b of the second power output component, and the second transmission gear 9' and the first transmission gear 10' are coaxially fixedly connected.

[0132] In the first stroke (i.e., the clockwise stroke), the rocker gear 4 rotates clockwise, the first one-way clutch 5a locks, and the rocker gear 4 drives the first output shaft 6a' and the first gear 7a to rotate clockwise through the first one-way clutch 5a, and outputs power; at the same time, the second one-way clutch 5b disengages, and the second output shaft 6b' and the second gear 7b can rotate counterclockwise without restraint.

[0133] In the second stroke (i.e., the counterclockwise stroke), the rocker gear 4 rotates counterclockwise, the second one-way clutch 5b locks, and the rocker gear 4 drives the second output shaft 6b' and the second gear 7b to rotate counterclockwise through the second one-way clutch 5b, and outputs power; at the same time, the first one-way clutch 5a disengages, and the first output shaft 6a' and the first gear 7a can rotate clockwise without restraint.

[0134] In short, during the first stroke, the rocker gear 4 rotates clockwise, the first power output component rotates clockwise and drives the transmission, and the second power output component rotates counterclockwise and idles. During the second stroke, the rocker gear 4 rotates counterclockwise, the first power output component rotates clockwise and idles, and the second power output component rotates counterclockwise and drives the transmission.

[0135] The first power take-off component maintains a constant rotation direction (i.e., rotates clockwise), driving in the first stroke and idling in the second stroke; similarly, the second power take-off component maintains a constant rotation direction (i.e., rotates counterclockwise), idling in the first stroke and driving in the second stroke. The first and second power take-off components alternately drive and idle, with one output component driving and outputting power in each stroke of the engine.

[0136] The first and second power output components can be connected to loads (such as generators) respectively to output power.

[0137] To convert the rocking rotation of the rocker gear 4 into a motion with a constant rotation direction and alternating transmission and free rotation, two one-way clutches are used. When the rocker gear 4 rotates clockwise, the first one-way clutch 5a is locked, the first power output component is driven, and the second one-way clutch 5b is disengaged, allowing the second power output component to idle. When the rocker gear 4 rotates counterclockwise, the first one-way clutch 5a is disengaged, the first power output component is idle, and the second one-way clutch 5b is locked, allowing the second power output component to drive.

[0138] The rocker gear 4 can be directly connected to two one-way clutches, or it can be connected through several transmission components.

[0139] As shown in Figure 13, the rocker gear 4 is directly connected to the first one-way clutch 5a and the second one-way clutch 5b; the rocker gear 4 drives the first power output component to rotate clockwise through the first one-way clutch 5a, and drives the second power output component to rotate counterclockwise through the second one-way clutch 5b.

[0140] Therefore, the first power output component can output power independently, with a constant rotation direction, alternating between transmission and idling; the second power output component can also output power independently, with a constant rotation direction, alternating between transmission and idling; and the transmission of the two power output components is complementary: one power output component is always in transmission while the other is idling. This embodiment has two power output components, each with a constant rotation direction, alternating between power output and idling (i.e., outputting intermittent torque). This can meet the needs of different drive systems, such as driving two generators to generate electricity as a range extender in a range-extended hybrid vehicle. However, vehicle engines typically have a single output shaft and output continuous and stable power. Therefore, it is necessary to design an engine with a single output shaft, as in this embodiment, that outputs continuous and uninterrupted power.

[0141] When the rocker gear 4 rotates clockwise, it drives the first power output component to rotate; when the rocker gear 4 rotates counterclockwise, it drives the second power output component to rotate. The rotation direction can be adjusted by the second coupling mechanism 300, which couples the two power output components together to form an output shaft.

[0142] The first output shaft 6a' and the first gear 7a are fixedly connected and rotate in the same direction on the same axis. The first gear 7a meshes with the coupling gear 8' and rotates in opposite directions, as do the coupling gear 8' and the first transmission gear 10'.

[0143] The second output shaft 6b' and the second gear 7b are fixedly connected and rotate in the same direction on the same axis. The second gear 7b meshes with the first transmission gear 10', and they rotate in opposite directions.

[0144] The first transmission gear 10' and the second transmission gear 9' are coaxially fixedly connected to achieve rotation in the same direction.

[0145] In the first stroke (clockwise stroke), the rocker gear 4 rotates clockwise, the first one-way clutch 5a locks, and the rocker gear 4 drives the first output shaft 6a' to rotate clockwise through the first one-way clutch 5a. Simultaneously, the first gear 7a follows the first output shaft 6a' clockwise transmission. The first gear 7a drives the coupling gear 8' to rotate counterclockwise, and the coupling gear 8' drives the first transmission gear 10' and the second transmission gear 9' to rotate clockwise together and transmit power. At the same time, the second one-way clutch 5b disengages, and the second output shaft 6b' can rotate counterclockwise without restraint, that is, the second transmission gear 9' drives the second gear 7b and the second output shaft 6b' to rotate counterclockwise without restraint.

[0146] In the second stroke (counterclockwise stroke), the rocker gear 4 rotates counterclockwise, the second one-way clutch 5b locks, and the rocker gear 4 drives the second output shaft 6b' to rotate counterclockwise through the second one-way clutch 5b. The second gear 7b follows the second output shaft 6b' in counterclockwise transmission. The second gear 7b drives the second transmission gear 9' and the first transmission gear 10' to rotate clockwise together and transmit power. At the same time, the first one-way clutch 5a disengages, and the first output shaft 6a' can rotate clockwise without restraint. That is, the first transmission gear 10' drives the coupling gear 8' to rotate counterclockwise, and the coupling gear 8' drives the first gear 7a and the first output shaft 6a' to rotate clockwise together.

[0147] As can be seen, in the first stroke, the rocker gear 4 rotates clockwise, and drives the shafts of the first transmission gear 10' and the second transmission gear 9' to rotate clockwise and transmit power through the first one-way clutch 5a, the first power output component and the coupling gear 8', and drives the second power output component to rotate counterclockwise through the second transmission gear 9'; in the second stroke, the rocker gear 4 rotates counterclockwise, and drives the shafts of the second transmission gear 9' and the first transmission gear 10' to rotate clockwise and transmit power through the second one-way clutch 5b and the second power output component, and drives the first power output component to rotate clockwise through the first transmission gear 10' and the coupling gear 8'.

[0148] Regardless of whether it rotates clockwise or counterclockwise, the rocker gear 4 always drives the shafts of the second transmission gear 9' and the first transmission gear 10' to rotate clockwise (through different paths). The common shaft of the second transmission gear 9' and the first transmission gear 10' can serve as the total output shaft to output power. In this way, the two separate power output components are coupled together by the second coupling mechanism 300 to form a single output shaft, outputting continuous and stable power or torque.

[0149] In one working cycle of the piston engine of this embodiment, the piston engine of this embodiment has a variable stroke and compression ratio. The variable compression ratio allows the use of different fuels to improve the flexibility and adaptability of the engine, and can also promote HCCI combustion to ensure higher thermal efficiency (i.e., thermal efficiency up to 60%). It can also improve the potential for SI-HCCI conversion through the variable compression ratio.

[0150] The piston engine of this embodiment eliminates complex components such as pushrods, crankshafts, high-pressure oil bearings, and high-pressure oil pumps found in existing technologies. This not only reduces overall costs but also converts the linear reciprocating motion of the piston into rotary motion by using a pushrod with a rack to drive the same rocker gear 4. This outputs rotational power to drive a rotary generator with stable power generation efficiency, thereby improving the conversion efficiency of mechanical energy into electrical energy. It also improves engine efficiency and can be used as a direct power source for driving HEV, PHEV, and REEV vehicles.

[0151] In this embodiment, the push rod is positioned at the pressure center of the piston to ensure that the eccentric force generated by the push rod is very small and negligible, thereby reducing energy loss and improving engine efficiency.

[0152] Furthermore, in this embodiment, the four cylinders work together in a coordinated manner to achieve a sequential reciprocating cycle of four stroke stages. The two push rods are arranged in parallel, with only one rocker gear 4 positioned in the middle, meshing with the racks of the two push rods respectively, ensuring that the two racks achieve motion coupling through the rocker gear 4. Compared to existing two-stroke engines, the piston engine in this embodiment has exhaust and intake strokes to ensure high-quality exhaust and intake. The driving force generated by the power stroke drives the piston to compress and expel the exhaust gas, leaving very little residual exhaust gas. In the next stroke, the piston movement creates negative pressure inside the cylinder, drawing in air and improving scavenging efficiency. Additionally, fresh gas containing fuel is not short-circuited out, avoiding fuel loss, and a higher effective compression ratio can be achieved, making it more suitable for the HCCI combustion cycle, improving efficiency. It also allows for the use of existing piston engine components, reducing manufacturing costs.

[0153] Of course, in other embodiments, if the transmission unit adopts a double rocker gear design, the two rocker gears need to withstand the huge thrust output by the piston during operation, and the load fluctuates greatly. The technical requirements for the gears, gear shafts, and bearings are high, and the cost is also high. Arranging two rocker gears between two cylinders requires more space, and the stiffness of the push rod needs to be enhanced. However, this embodiment uses a transmission unit with a single rocker gear, which can reduce costs, reduce size and weight, and improve design flexibility.

[0154] In this embodiment, the lever arm of the push rod force on the drive shaft is equal to the radius of the rocker gear 4. At the beginning of the power stroke, when the combustion energy in the cylinder is at its maximum, the energy can be quickly transferred out, reducing leakage and heat loss, thereby improving engine efficiency.

[0155] When the piston of a piston engine is around top dead center, its acceleration is significantly higher, thereby reducing the residence time at high temperatures and reducing heat transfer losses during combustion. When the piston of a piston engine is around bottom dead center, the lever arm of the push rod does not decrease, and the output power decays less, so as to achieve small output power fluctuations.

[0156] In addition, compared with the piston engines of the prior art which have strong vibrations in the three axes of x, y and z, the piston engine of this embodiment only has strong vibrations in one direction (i.e. the piston moves in the left and right directions), and the NVH (NVH includes noise, vibration and acoustic roughness) characteristics are significantly improved.

[0157] Example 6

[0158] As shown in Figure 14, Embodiment Six provides a free piston engine. Embodiment Six and Embodiment Five have largely the same structure, except that: the first power output component and the second power output component are both output wheels, a first one-way clutch 5a is provided between the shaft of the first power output component and the rocker gear 4, and a second one-way clutch 5b is provided between the shaft of the second power output component and the rocker gear 4.

[0159] In this specific embodiment, the first power output component is the first gear 7a, and the second power output component is the second gear 7b.

[0160] The rocker gear 4 is connected to the first one-way clutch 5a and the second one-way clutch 5b via its own shaft; the rocker gear 4 drives the first power output component to rotate clockwise via its own shaft and the first one-way clutch 5a, and drives the second power output component to rotate counterclockwise via its own shaft and the second one-way clutch 5b.

[0161] The first one-way clutch 5a is arranged between the shaft of the rocker gear 4 and the first gear 7a, and the second one-way clutch 5b is arranged between the shaft of the rocker gear 4 and the second gear 7b. The first gear 7a meshes with the coupling gear 8' and rotates in opposite directions; the coupling gear 8' meshes with the first transmission gear 10' and rotates in opposite directions; the second gear 7b meshes with the first transmission gear 10' and rotates in opposite directions.

[0162] First stroke: The rocker gear 4 rotates clockwise, the first one-way clutch 5a locks, the rocker gear 4 drives the first gear 7a to rotate clockwise through the first one-way clutch 5a, the first gear 7a drives the coupling gear 8' to rotate counterclockwise and transmit power, the coupling gear 8' drives the first transmission gear 10' and the first transmission gear 10' together to rotate clockwise and transmit power. At the same time, the second one-way clutch 5b disengages. Since the second gear 7b can rotate freely without restraint, the first transmission gear 10' can drive the second gear 7b to rotate counterclockwise.

[0163] Second stroke: The rocker gear 4 rotates counterclockwise, the second one-way clutch 5b locks, and the rocker gear 4 drives the second gear 7b to rotate counterclockwise through the second one-way clutch 5b. The second gear 7b drives the first transmission gear 10' and the first transmission gear 10' to rotate clockwise together and transmit power. At this time, the first transmission gear 10' drives the coupling gear 8' to rotate counterclockwise. At the same time, the first one-way clutch 5a disengages. Since the first gear 7a can rotate freely without restraint, the coupling gear 8' can drive the first gear 7a to rotate clockwise freely.

[0164] In summary, during the first stroke: the rocker gear 4 rotates clockwise, and through the first one-way clutch 5a, the first power output component, and the coupling gear 8', it drives the shafts of the first transmission gear 10' and the second transmission gear 9' to rotate clockwise and transmit power, while the second transmission gear 9' drives the second power output component to rotate counterclockwise. During the second stroke: the rocker gear 4 rotates counterclockwise, and through the second one-way clutch 5b and the second power output component, it drives the shafts of the second transmission gear 9' and the first transmission gear 10' to rotate clockwise and transmit power, while the first transmission gear 10' and the coupling gear 8' drive the first power output component to rotate clockwise.

[0165] Regardless of whether it rotates clockwise or counterclockwise, the rocker gear 4 always drives the shafts of the second transmission gear 9' and the first transmission gear 10' to rotate clockwise (through different paths). The common shaft of the second transmission gear 9' and the first transmission gear 10' can serve as the total output shaft to output power. In this way, the two separate power output components are coupled together by the second coupling mechanism 300 to form a single output shaft, outputting continuous and stable power or torque.

[0166] Example 7

[0167] As shown in Figure 15, Embodiment 7 provides a free piston engine. The structure of Embodiment 7 is generally the same as that of Embodiment 5, except that the transmission unit further includes a transmission gear set 200. The shaft of the rocker gear 4 is fixedly connected to the transmission gear set 200. The transmission gear set 200 is driven to connect to the first power output component through the first one-way clutch 5a, and to connect to the second power output component through the second one-way clutch 5b, thereby forming an indirect drive configuration.

[0168] In this specific embodiment, the first power output component includes a first output shaft 6a' connected to the first one-way clutch 5a and a first gear 7a fixed to the first output shaft 6a'; the second power output component includes a second output shaft 6b' connected to the second one-way clutch 5b and a second gear 7b fixed to the second output shaft 6b', and the first gear 7a and the second gear 7b mesh with each other.

[0169] The transmission gear set 200 includes transmission gear A, transmission gear B and transmission gear C, wherein transmission gear A is fixed on the shaft of rocker gear 4, and transmission gear B and transmission gear C are respectively meshed with transmission gear A.

[0170] The rocker gear 4 is connected to the first one-way clutch 5a via transmission gear A and transmission gear B, and is also connected to the second one-way clutch 5b via transmission gear A and transmission gear C. The rocker gear 4 drives the first power output component to rotate counterclockwise via transmission gear A, transmission gear B and the first one-way clutch 5a, and drives the second power output component to rotate clockwise via transmission gear A, transmission gear C and the second one-way clutch 5b.

[0171] The rocker gear 4 is driven to connect with the first output shaft 6a' through the transmission gear A, the transmission gear B and the first one-way clutch 5a, so as to form the first torque transmission route of indirect drive.

[0172] The rocker gear 4 is driven to connect with the second output shaft 6b' via the transmission gear A, the transmission gear C, and the second one-way clutch 5b, to form a second torque transmission route for indirect drive.

[0173] First stroke: The rocker gear 4 and the transmission gear A rotate clockwise together. The transmission gear A drives the transmission gears B and C to rotate counterclockwise simultaneously. The first one-way clutch 5a is locked. The transmission gear B drives the first output shaft 6a' and the first gear 7a to rotate counterclockwise through the first one-way clutch 5a. At the same time, the second one-way clutch 5b is disengaged. Since the second output shaft 6b' and the second gear 7b can rotate freely without restraint, the first gear 7a drives the second gear 7b and the second output shaft 6b' to rotate clockwise freely.

[0174] Second stroke: The rocker gear 4 and the transmission gear A rotate counterclockwise together. The transmission gear A drives the transmission gears B and C to rotate clockwise simultaneously. The second one-way clutch 5b is locked. The transmission gear C drives the second output shaft 6b' and the second gear 7b to rotate clockwise through the second one-way clutch 5b. At the same time, the first one-way clutch 5a is disengaged. Since the first output shaft 6a' and the first gear 7a can rotate freely without restraint, the second gear 7b drives the first gear 7a and the first output shaft 6a' to rotate counterclockwise.

[0175] In summary, during the first stroke: the rocker gear 4 rotates clockwise, and through transmission gear A, transmission gear B and the first one-way clutch 5a, drives the first power output component to rotate counterclockwise and transmit power; during the second stroke: the rocker gear 4 rotates counterclockwise, and through transmission gear A, transmission gear C and the second one-way clutch 5b, drives the second power output component to rotate clockwise, which in turn drives the first power output component to rotate counterclockwise and transmit power; the first power output component serves as the main output shaft.

[0176] Regardless of whether it rotates clockwise or counterclockwise, the rocker gear 4 always drives the second power output component to rotate clockwise (through different paths), and the second power output component can act as the main output shaft to output power. In this way, the two separate output components are coupled together by the second coupling mechanism 300 to form a single output shaft, outputting continuous and stable power or torque.

[0177] Example 8

[0178] As shown in Figure 16, Embodiment 8 provides a free piston engine. The structure of Embodiment 8 is generally the same as that of Embodiment 5, except that: the second coupling mechanism 300' further includes a transmission gear set 200', the first power output component is a first gear 7a, and the shaft of the rocker gear 4 is directly driven to the first gear 7a through a first one-way clutch 5a; the second power output component includes a second output shaft 6b' connected to a second one-way clutch 5b and a second gear 7b fixed to the second output shaft 6b', and the transmission gear set 200' is driven to the second output shaft 6b' through the second one-way clutch 5b; the first gear 7a is driven to the second gear 7b through a coupling gear 8'.

[0179] The transmission gear set 200' includes a transmission gear D and a transmission gear E, wherein the transmission gear D is fixed on the shaft of the rocker gear 4.

[0180] The rocker gear 4 is connected to the first one-way clutch 5a via its own shaft, and to the second one-way clutch 5b via transmission gears D and E. The rocker gear 4 drives the first power output component to rotate clockwise via its own shaft and the first one-way clutch 5a, and drives the second power output component to rotate clockwise via transmission gears D, E and the second one-way clutch 5b.

[0181] The second output shaft 6b' and the second gear 7b are coaxially fixedly connected, and the first gear 7a and the second output wheel 7a mesh through the coupling gear 8' to achieve power coupling.

[0182] First stroke: The rocker gear 4 and the transmission gear D rotate clockwise together. The transmission gear D drives the transmission gear E to rotate counterclockwise. The first one-way clutch 5a is locked. The rocker gear 4 drives the first gear 7a to rotate clockwise through the first one-way clutch 5a. The first gear 7a drives the coupling gear 8' to rotate counterclockwise and transmits power. At the same time, the second one-way clutch 5b is disengaged. Since the second output shaft 6b' and the second gear 7b can rotate freely without restraint, the coupling gear 8' drives the second gear 7b and the second output shaft 6b' to rotate clockwise.

[0183] It can be seen that the torque transmission route of the first stroke is as follows: the rocker gear 4, the first gear 7a and the coupling gear 8' transmit power in sequence.

[0184] Second stroke: The rocker gear 4 and the transmission gear D rotate counterclockwise together. The transmission gear D drives the transmission gear E to rotate clockwise. The second one-way clutch 5b is locked. The transmission gear E drives the second output shaft 6b' and the second gear 7b to rotate clockwise through the second one-way clutch 5b. The second gear 7b drives the coupling gear 8' to rotate counterclockwise and transmit power. At the same time, the first one-way clutch 5a is disengaged. Since the first gear 7a can rotate freely without restraint, the coupling gear 8' drives the first gear 7a to rotate clockwise.

[0185] It can be seen that the torque transmission route of the second stroke is as follows: the rocker gear 4, the transmission gear D, the transmission gear E, the second output shaft 6b', the second gear 7b and the coupling gear 8' transmit power in sequence.

[0186] When the piston engine is working, the four cylinders work in sequence to make the piston and push rod of the cylinder move back and forth and complete one working cycle. In each working cycle, the coupling gear 8' rotates counterclockwise continuously and outputs power.

[0187] In summary, during the first stroke, the rocker gear 4 rotates clockwise and drives the second power output component to rotate clockwise via its own shaft, the first one-way clutch 5a, the first power output component, and the coupling gear 8'; during the second stroke, the rocker gear 4 rotates counterclockwise and drives the second power output component to rotate clockwise via its own shaft, the transmission gear D, the transmission gear E, and the second one-way clutch 5b; the second power output component outputs power or torque as the main output shaft.

[0188] Regardless of whether it rotates clockwise or counterclockwise, the rocker gear 4 always drives the second power output component to rotate clockwise (through different paths), and the second power output component can act as the main output shaft to output power. In this way, the two separate power output components are coupled together by the second coupling mechanism 300' to form a single output shaft, outputting continuous and stable power or torque.

[0189] Example 9

[0190] Example 9 provides a free piston engine. The structure of Example 9 is generally the same as that of Example 5, except that the two push rods are integrally connected and move synchronously in the same direction. The racks on the two push rods are set on the same side, and the same rocker gear meshes with the racks on the two push rods at the same time.

[0191] In this embodiment, two push rods are integrally connected to form a single push rod, and then connected one by one by two rack gears to form a new rack on the integral push rod. The new rack and the rocker gear are arranged on the same side of the two push rods, and the rocker gear meshes with the new rack. In this way, it can be achieved that the piston of one cylinder is always doing work, and simultaneously driving the other three cylinders to complete the intake stroke, compression stroke and exhaust stroke respectively.

[0192] Of course, in other embodiments, the gears of the two racks can also be independent of each other, and the gear of the same rocker gear is wider to overcome the gap between the two racks, thereby ensuring that the rocker gear meshes with the two racks at the same time.

[0193] Although the invention has been specifically shown and described in conjunction with preferred embodiments, those skilled in the art should understand that various changes in form and detail may be made to the invention without departing from the spirit and scope of the invention as defined in the appended claims, all of which shall be within the scope of protection of the invention.

Claims

1. A free piston engine, comprising at least one cylinder bank, the cylinder bank comprising two opposing cylinders, the pistons of the two cylinders in each bank being connected by a push rod, the push rod being provided with a rack, characterized in that: It also includes a transmission unit; The transmission unit includes a rocker gear, a first one-way clutch, a second one-way clutch, a first power output component, and a second power output component. The rocker gear is configured to rotate around a fixed axis and meshes with the rack. The rocker gear is connected to the first power output component via the first one-way clutch, and the rocker gear is connected to the second power output component via the second one-way clutch.

2. The free piston engine according to claim 1, characterized in that: The number of cylinder groups is one set; Each linear reciprocating motion of the piston corresponds to the first stroke and the second stroke in sequence, forming a working cycle. During the engine's cyclic operation, the piston pushes the push rod to perform a linear reciprocating motion. In the first stroke, the push rod drives the rocker gear to rotate in a first direction through the rack. The rocker gear is connected to the first power output component through the first one-way clutch to ensure that the first power output component transmits torque. At the same time, the second one-way clutch is disengaged to ensure that the second power output component rotates in the same direction as the rotation direction of the previous stroke. In the second stroke, the push rod drives the rocker gear to rotate in a second direction opposite to the first direction through the rack. The rocker gear is connected to the second power output component through the second one-way clutch to ensure that the second power output component transmits torque, and the first one-way clutch is simultaneously disengaged so that the first power output component can idle in the same direction as the rotation direction of the previous stroke. The first power output component and the second power output component alternately transmit and output engine torque, and their respective rotation directions remain unchanged.

3. The free piston engine according to claim 2, characterized in that: The transmission unit further includes a first coupling mechanism, through which the first power output component and the second power output component are connected, coupling the power output alternately from the two power output components into a single and continuous power output, and the direction of rotation remains unchanged.

4. The free piston engine according to claim 2, characterized in that: The rocker gear is directly driven to the first power output component via the first one-way clutch, and the rocker gear is directly driven to the second power output component via the second one-way clutch.

5. The free piston engine according to claim 4, characterized in that: The first power output component and the second power output component are respectively an output shaft or an output wheel for outputting torque.

6. The free piston engine according to claim 3, characterized in that: The rocker gear and / or the first power output component and / or the second power output component are connected by the first coupling mechanism to couple the power output of every two consecutive strokes and ensure continuous power output, while the power output direction remains unchanged.

7. The free piston engine according to claim 6, characterized in that: The first coupling mechanism includes a coupling gear and a first output gear and a second output gear arranged coaxially. The first power output component includes a first output shaft lockably connected to the first one-way clutch and a first gear fixed to the first output shaft. The second power output component includes a second output shaft lockably connected to the second one-way clutch and a second gear fixed to the second output shaft. The first output gear is driven to connect to the first gear through the coupling gear, and the second output gear meshes with the second gear.

8. The free piston engine according to claim 6, characterized in that: The first coupling mechanism includes a coupling gear and a first output gear and a second output gear arranged coaxially. Both the first power output component and the second power output component are gears. A first one-way clutch is provided between the shaft of the first power output component and the shaft of the rocker gear, and a second one-way clutch is provided between the shaft of the second power output component and the shaft of the rocker gear. The first output gear is driven to connect to the first power output component through the coupling gear, and the second output gear is engaged with the second power output component.

9. The free piston engine according to claim 6, characterized in that: The first coupling mechanism includes a transmission gear set, the shaft of the rocker gear is fixedly connected to the transmission gear set, the transmission gear set is driven to the first power output component through the first one-way clutch, and is driven to the second power output component through the second one-way clutch, thereby forming an indirect drive configuration.

10. The free piston engine according to claim 9, characterized in that: The first power output component includes a first output shaft lockably connected to the first one-way clutch and a first gear fixed to the first output shaft; the second power output component includes a second output shaft lockably connected to the second one-way clutch and a second gear fixed to the second output shaft, wherein the first gear and the second gear mesh.

11. The free piston engine according to claim 6, characterized in that: The first coupling mechanism includes a coupling gear and a transmission gear set. The shaft of the rocking gear is fixedly connected to the transmission gear set. The first power output component is a gear. The shaft of the rocking gear is directly driven to the first power output component through the first one-way clutch. The second power output component includes a second output shaft lockably connected to the second one-way clutch and a second gear fixed to the second output shaft. The transmission gear set is driven to the second output shaft through the second one-way clutch. The first power output component is driven to the second gear through the coupling gear.

12. The free piston engine according to claim 1, characterized in that: The cylinder group is set in two groups. The pistons of the two cylinders in the same group are connected by corresponding push rods. Each push rod is equipped with a rack. The rocker gear meshes with the racks on the two push rods. Each cylinder sequentially completes the intake stroke, compression stroke, power stroke, and exhaust stroke; the system forms a working cycle every four strokes, and in each stroke, the piston of one cylinder is always doing work, and simultaneously drives the other three cylinders to complete the intake stroke, compression stroke, and exhaust stroke through the joint cooperation of the push rod, the rack, and the rocker gear. In the first stroke, only one power piston drives the rocker gear to rotate in the first direction via the rack of the push rod; In the second stroke, only one power piston drives the rocker gear to rotate in a second direction opposite to the first direction via the rack of the push rod; In the third stroke, only one power piston drives the rocker gear to rotate in the first direction via the rack of the push rod; in the fourth stroke, only one power piston drives the rocker gear to rotate in the second direction via the rack of the push rod. When the rocker gear rotates in the first direction, the first one-way clutch engages, the rocker gear transmits torque and outputs power through the first power output component, and simultaneously the second one-way clutch disengages, and the second power output component idles in the same direction as the rotation direction of the previous stroke. When the rocker gear rotates in the second direction, the first one-way clutch disengages, the first power output component rotates freely in the same direction as the rotation direction of the previous stroke, and the second one-way clutch engages synchronously. The rocker gear transmits torque and outputs power through the second power output component.

13. The free piston engine according to claim 12, characterized in that: It also includes a second coupling mechanism; the first power output component and the second power output component are coupled through the second coupling mechanism to output continuous power.

14. The free piston engine according to claim 12, characterized in that: One cylinder in one group generates a driving force during its power stroke to push its piston in a first direction; and through the transmission unit, it drives the piston of another cylinder in the same group to move in the first direction to achieve the compression stroke, and simultaneously drives the pistons of the third and fourth cylinders in another group to move in a second direction opposite to the first direction, so that the third and fourth cylinders in the other group complete the intake stroke and the exhaust stroke respectively; or it drives the piston of another cylinder in the same group to move in the first direction to achieve the exhaust stroke, and simultaneously drives the pistons of the third and fourth cylinders in another group to move in a second direction opposite to the first direction, so that the third and fourth cylinders in the other group complete the intake stroke and the compression stroke respectively.

15. The free piston engine according to claim 12, characterized in that: The racks of the two push rods are single-sided racks and are arranged opposite to each other; the rocker gear is arranged between the racks of the two push rods.

16. The free piston engine according to claim 12, characterized in that: The two push rods are connected as a single unit and move synchronously in the same direction; the racks on the two push rods are located on the same side, and the rocker gear meshes with the racks on both push rods simultaneously.

17. The free piston engine according to claim 16, characterized in that: The gears of the two racks are connected one to one; or the gears of the two racks are independent of each other.

18. The free piston engine according to claim 13, characterized in that: The rocker gear is directly driven to the first power output component via the first one-way clutch, and the rocker gear is directly driven to the second power output component via the second one-way clutch.

19. The free piston engine according to claim 18, characterized in that: The first power output component includes a first output shaft connected to the first one-way clutch and a first gear fixed to the first output shaft; the second power output component includes a second output shaft connected to the second one-way clutch and a second gear fixed to the second output shaft.

20. The free piston engine according to claim 19, characterized in that: The second coupling mechanism includes a coupling gear and a first transmission gear and a second transmission gear arranged coaxially. The first transmission gear is driven to connect to the first gear through the coupling gear, and the second transmission gear is driven to connect to the second gear.

21. The free piston engine according to claim 13, characterized in that: Both the first power output component and the second power output component are gears. A first one-way clutch is provided between the shaft of the first power output component and the shaft of the rocker gear, and a second one-way clutch is provided between the shaft of the second power output component and the shaft of the rocker gear.

22. The free piston engine according to claim 21, characterized in that: The second coupling mechanism includes a coupling gear and a first transmission gear and a second transmission gear arranged coaxially. The first transmission gear is driven to connect to the first power output component through the coupling gear, and the second transmission gear is driven to connect to the second power output component.

23. The free piston engine according to claim 13, characterized in that: The transmission unit includes a transmission gear set; the shaft of the rocker gear is fixedly connected to the transmission gear set, and the transmission gear set is driven to the first power output component through the first one-way clutch and driven to the second power output component through the second one-way clutch, thereby forming an indirect drive configuration.

24. The free piston engine according to claim 23, characterized in that: The first power output component includes a first output shaft connected to the first one-way clutch and a first gear fixed to the first output shaft; the second power output component includes a second output shaft connected to the second one-way clutch and a second gear fixed to the second output shaft, wherein the first gear and the second gear mesh.

25. The free piston engine according to claim 13, characterized in that: The second coupling mechanism includes a coupling gear and a transmission gear set. The shaft of the rocking gear is fixedly connected to the transmission gear set. The first power output component is a first gear. The shaft of the rocking gear is directly driven to the first gear through the first one-way clutch. The second power output component includes a second output shaft connected to the second one-way clutch and a second gear fixed to the second output shaft. The transmission gear set is driven to the second output shaft through the second one-way clutch. The first gear is driven to the second gear through the coupling gear.

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