Free-piston engine

Abstract

A free-piston engine, comprising at least one cylinder bank, which comprises two cylinders arranged opposite each other, and further comprising a transmission unit, wherein the transmission unit comprises two oscillating gears, and one-way clutches and transmission shafts that respectively match the oscillating gears; the oscillating gears are set in fixed-axis rotation; pistons of the two cylinders in the cylinder bank are connected by means of a push rod (3); the push rod (3) is provided with a rack (31); the oscillating gears mesh with the racks (31); and by means of the one-way clutches, the oscillating gears are in transmission connection with the transmission shafts corresponding thereto. The free-piston engine can eliminate a complex transmission mechanism composed of connecting rods, crankshafts, etc., and converts a linear reciprocating motion of the pistons into a rotational motion for output, thereby improving engine efficiency.

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 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.

[0004] At the beginning of the power stroke, the pressure inside the cylinder is at its maximum, but the crankshaft is close to top dead center at this time, the pushrod lever arm on the crankshaft is very small, the torque generated is small, and therefore the output power is also small. At the same time, the energy contained in the high temperature and high pressure gas is released slowly, and the energy loss caused by gas leakage and heat loss also increases accordingly.

[0005] When the power stroke is nearing its end, the crankshaft is close to bottom dead center, the pushrod lever arm on the crankshaft is small, the pressure inside the cylinder is small, and therefore the output power is also small, which reduces the engine's power density and increases the fluctuation of output power.

[0006] In addition, the load between the pushrod and the crankshaft, and between the crankshaft and the housing, is very large, resulting in significant frictional losses. Furthermore, high-pressure oil is required to lubricate the bearings, and the oil pump consumes energy, thereby reducing engine efficiency. Summary of the Invention

[0007] 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 transforms the linear reciprocating motion of the piston into rotational motion to output rotational power, thereby improving engine efficiency.

[0008] To achieve the above objectives, the technical solution provided by the present invention is as follows:

[0009] This invention provides a free piston engine, comprising at least one cylinder bank, the cylinder bank including two opposing cylinders, and a transmission unit; the transmission unit includes two rocker gears, a one-way clutch engaging each rocker gear, and a transmission shaft, the rocker gears being fixed-axis rotatable; the pistons of the two cylinders in the cylinder bank are connected by push rods, the push rods being provided with racks, the rocker gears meshing with the racks, and the rocker gears being driven by the one-way clutches to their corresponding transmission shafts.

[0010] This invention provides a free piston engine, wherein the number of cylinder groups is one; the rocker gears all mesh with the rack; each piston performs a linear reciprocating motion to form two strokes; in each stroke, one cylinder is compressing and the other cylinder is performing work; one linear reciprocating motion of the piston forms a cycle, and the locking directions of the two one-way clutches are set to be opposite to each other to ensure that the two drive shafts alternately output torque and idle in the two strokes of one reciprocating motion, and the idle direction of the two drive shafts is the same as the transmission rotation direction.

[0011] In one embodiment, the rack is a single-sided rack, and the two rocker gears are both located on the same side of the corresponding push rod; the rotation directions of the two drive shafts are set to be opposite to each other.

[0012] In one embodiment, the two rocker gears are spaced apart.

[0013] Furthermore, each of the two drive shafts is equipped with an output gear for outputting torque, so as to achieve alternating torque output.

[0014] Furthermore, meshing coupling gears are provided on the two drive shafts respectively, and one of the drive shafts is provided with an output gear for outputting torque, so as to achieve continuous output torque.

[0015] In one embodiment, the rack is a double-sided rack, with two rocker gears respectively disposed on both sides of the corresponding push rod; the rotation directions of the two drive shafts are the same.

[0016] Furthermore, each of the two drive shafts is equipped with an output gear for outputting torque, so as to achieve alternating torque output.

[0017] Furthermore, a first gear and a second gear are respectively provided on the two drive shafts. The first gear and the second gear are both meshed with a coupling gear to form a coupling configuration for alternating power transmission. The coupling gear is equipped with a connecting shaft, and the connecting shaft is provided with an output gear for outputting torque to achieve continuous torque output.

[0018] This invention provides a free piston engine, wherein the cylinder bank consists of two sets; the pistons of the two sets of cylinders are connected by corresponding push rods; each push rod is equipped with a rack, one of which has a rocker gear meshing with the racks of both push rods, and the other has a rocker gear meshing with at least one push rod rack; each cylinder sequentially completes the intake stroke, compression stroke, power stroke, and exhaust stroke, forming a cycle, and there is always one cylinder piston performing power, synchronously driving the other three cylinders to complete the intake stroke, compression stroke, and exhaust stroke respectively, and the locking directions of the two one-way clutches are set to be opposite to each other, so as to ensure that one of the two drive shafts is outputting torque, while the other is idling, and the idling direction of the drive shaft is the same as the transmission rotation direction.

[0019] 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.

[0020] In one embodiment, the racks of the two push rods are single-sided racks and are arranged opposite to each other; two rocker gears are arranged between the racks of the two push rods, and the two rocker gears mesh with the two racks one by one; the rotation directions of the two drive shafts are set to be opposite to each other.

[0021] Furthermore, each of the two drive shafts is equipped with an output gear for outputting torque.

[0022] Furthermore, a coupling mechanism is provided between the two drive shafts to couple the power of the two drive shafts, ensuring that the output rotation direction remains unchanged and that the output rotational power is continuous and uninterrupted.

[0023] In one embodiment, one push rod has a single-sided rack and the other push rod has a double-sided rack; a rocker gear is disposed between the two push rods and meshes with the racks of the two push rods respectively; another rocker gear is disposed on the side of the double-sided rack away from the single-sided rack and meshes with the double-sided rack; the two drive shafts rotate in the same direction.

[0024] Furthermore, each of the two drive shafts is equipped with an output gear for outputting torque.

[0025] Furthermore, a coupling mechanism is provided between the two drive shafts to couple the power of the two drive shafts, ensuring that the output rotation direction remains unchanged and that the output rotational power is continuous and uninterrupted.

[0026] 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 set on the same side, and the two rocker gears are set on the rack side of the two push rods, with the two rocker gears meshing with the two racks one by one; the rotation directions of the two drive shafts are set to be opposite to each other.

[0027] Furthermore, the gears of the two racks are connected one-to-one; or the gears of the two racks are independent of each other.

[0028] The technical solution provided by this invention has the following beneficial effects:

[0029] This invention eliminates the complex transmission mechanism composed of crankshafts and other components found in existing technologies, thereby reducing overall costs. Furthermore, by using a push rod equipped with a rack to drive a corresponding rocker gear, the linear reciprocating motion of the piston is converted into rotational 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 enhancing engine efficiency. It can also serve as a direct power source for driving HEV, PHEV, and REEV vehicles. Attached Figure Description

[0030] Figure 1 shows a schematic diagram of a free piston engine in the first state in Embodiment 1;

[0031] Figure 2 shows a power output connection diagram of the free piston engine in Embodiment 1;

[0032] Figure 3 shows another power output connection diagram of the free piston engine in Embodiment 1;

[0033] Figure 4 shows a schematic diagram of the free piston engine in the second state in Embodiment 1;

[0034] Figure 5 shows a schematic diagram of the free piston engine in the third state in Embodiment 1;

[0035] Figure 6 shows a schematic diagram of the free piston engine in the fourth state in Embodiment 1;

[0036] Figure 7 shows a schematic diagram of the free piston engine in the first state in Embodiment 2;

[0037] Figure 8 shows a schematic diagram of the free piston engine in the second state in Embodiment 2;

[0038] Figure 9 shows a schematic diagram of the free piston engine in the third state in Embodiment 2;

[0039] Figure 10 shows a schematic diagram of the free piston engine in the fourth state in Embodiment 2;

[0040] Figure 11 shows a schematic diagram of one type of power output connection of the free piston engine in Embodiment 2;

[0041] Figure 12 shows a schematic diagram of the free piston engine in the first stroke stage in Embodiment 3;

[0042] Figure 13 shows a schematic diagram of the free piston engine in the second stroke stage in Embodiment 3;

[0043] Figure 14 shows a schematic diagram of the free piston engine in the third stroke stage in Embodiment 3;

[0044] Figure 15 shows a schematic diagram of the free piston engine in the fourth stroke stage in Embodiment 3;

[0045] Figure 16 shows a schematic diagram of the power output connection of the free piston engine in Embodiment 3;

[0046] Figure 17 shows another power output connection diagram of the free piston engine in Embodiment 3;

[0047] Figure 18 shows a schematic diagram of the free piston engine in the first stroke stage in Embodiment 4;

[0048] Figure 19 shows a schematic diagram of the free piston engine in the second stroke stage in Embodiment 4;

[0049] Figure 20 shows a schematic diagram of the free piston engine in the third stroke stage in Embodiment 4;

[0050] Figure 21 shows a schematic diagram of the free piston engine in the fourth stroke stage in Embodiment 4;

[0051] Figure 22 shows a schematic diagram of the power output connection of the free piston engine in Embodiment 4. Detailed Implementation

[0052] 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.

[0053] The present invention will now be further described in conjunction with the accompanying drawings and specific embodiments.

[0054] Example 1

[0055] Referring to Figures 1 to 6, Embodiment 1 provides a free piston engine (hereinafter referred to as a piston engine). The piston engine includes two cylinders arranged opposite each other. The piston engine also includes a transmission unit, which includes two rocker gears, a one-way clutch that engages with each rocker gear, and a transmission shaft. The pistons of the two cylinders are connected by a push rod 3. A rack 31 is provided on the push rod 3, and the rack 31 is a single-sided rack. The rocker gears mesh with the rack 31, and the rocker gears are connected to their corresponding transmission shafts through the one-way clutches, so that the rocker gears are configured to rotate on a fixed axis. That is, each rocker gear, its corresponding one-way clutch, and its transmission shaft are coaxially arranged, and it performs a fixed-axis rocker rotation, such as alternating clockwise or counterclockwise rotation, while the transmission shaft rotates in one direction.

[0056] Each time the piston makes a linear reciprocating motion, it forms two strokes. In each stroke, one cylinder is compressing and the other cylinder is doing work. Therefore, the piston engine in this embodiment is a two-stroke free piston engine.

[0057] One linear reciprocating motion of the piston forms a cycle, and the locking directions of the two one-way clutches are set to be opposite to each other to ensure that the two drive shafts alternately output torque and idle within two strokes of one reciprocating motion. Furthermore, the idle direction of the two drive shafts is the same as the transmission rotation direction. That is, in any stroke, one one-way clutch is always locked, causing the corresponding rocker gear and drive shaft to transmit power, while the other one-way clutch is disengaged, causing the corresponding drive shaft to rotate without load. This allows the two drive shafts to alternately output torque and idle within two strokes of one reciprocating motion, and the rotation direction of the two drive shafts remains unchanged whether they are transmitting power or rotating without load. The one-way engagement characteristic of the one-way clutch allows the drive shaft to continue rotating along the transmission direction and by inertia when unloaded.

[0058] In this embodiment, the two rocker gears are both located on the same side of the corresponding push rod 3 and are spaced apart from each other. The two one-way clutches are arranged in opposite directions, so that the rotation directions of the two drive shafts are opposite to each other. The two drive shafts are respectively provided with output gears for outputting torque, so as to realize alternating torque output.

[0059] In specific implementation, the two cylinders are a first cylinder 1a and a second cylinder 1b, which are symmetrically arranged with a left-right spacing. Both the first cylinder 1a and the second cylinder 1b are fixedly mounted on the engine housing. The first cylinder 1a is provided with a first combustion chamber and a first piston 2a, and the second cylinder 1b is provided with a second combustion chamber and a second piston 2b. The first piston 2a and the second piston 2b are fixedly connected by a push rod 3 so that the first piston 2a, the second piston 2b and the push rod 3 can make a left-right reciprocating linear motion together.

[0060] The two rocker gears are a first rocker gear 4a and a second rocker gear 4b, which are set on the left and right respectively. The two one-way clutches are a first one-way clutch 5a and a second one-way clutch 5b respectively. The two drive shafts are a first drive shaft 6a and a second drive shaft 6b respectively. A first output gear 8a for outputting torque is mounted on the first drive shaft 6a, and a second output gear 8b for outputting torque is mounted on the second drive shaft 6b.

[0061] Both the first one-way clutch 5a and the first drive shaft 6a are mounted on the first rocker gear 4a, and the first rocker gear 4a and the first drive shaft 6a are connected by the first one-way clutch 5a.

[0062] The second one-way clutch 5b and the second drive shaft 6b are both mounted on the second rocker gear 4b, and the second rocker gear 4b and the second drive shaft 6b are connected by the second one-way clutch 5b.

[0063] Both the first rocker gear 4a and the second rocker gear 4b mesh with the rack 31.

[0064] When push rod 3 moves in the first direction (e.g., to the right), rack 31 drives the first rocker gear 4a and the second rocker gear 4b to rotate clockwise; conversely, when push rod 3 moves in the second direction opposite to the first direction (e.g., to the left), rack 31 drives the first rocker gear 4a and the second rocker gear 4b to rotate counterclockwise.

[0065] When the first rocker gear 4a rotates clockwise, it is locked by the first one-way clutch 5a, so that the first rocker gear 4a and the first drive shaft 6a can be driven to rotate clockwise and transmit power.

[0066] When the first rocker gear 4a rotates counterclockwise, the first one-way clutch 5a is disengaged, so that the transmission connection between the first rocker gear 4a and the first drive shaft 6a is broken. That is, the first rocker gear 4a cannot drive the first drive shaft 6a to rotate counterclockwise, and they cannot transmit power to each other. At this time, the first drive shaft 6a continues to rotate clockwise by inertia.

[0067] When the second rocker gear 4b rotates counterclockwise, the second one-way clutch 5b is locked, so that the second rocker gear 4b and the second drive shaft 6b can be driven to rotate counterclockwise and transmit power.

[0068] When the second rocker gear 4b rotates clockwise, the second one-way clutch 5b is disengaged, so that the transmission connection between the second rocker gear 4b and the second drive shaft 6b is broken. That is, the second rocker gear 4b cannot drive the second drive shaft 6b to rotate clockwise, and they cannot transmit power to each other. At this time, the second drive shaft 6b continues to rotate counterclockwise by inertia.

[0069] In summary, when push rod 3 moves to the right, the first one-way clutch 5a locks, and the power output by push rod 3 is transmitted to the first drive shaft 6a through the first rocker gear 4a and the first one-way clutch 5a, rotating clockwise. At the same time, the second drive shaft 6b rotates counterclockwise without load. When push rod 3 moves to the left, the second one-way clutch 5b locks, and the power output by push rod 3 is transmitted to the second drive shaft 6b through the second rocker gear 4b and the second one-way clutch 5b, rotating counterclockwise. At the same time, the first drive shaft 6a rotates clockwise without load.

[0070] The piston engine in this embodiment is a two-stroke engine. A complete working cycle is formed by the two-stroke of the piston engine and the scavenging after the power stroke. Each cylinder completes the intake, compression, expansion power stroke and exhaust in one cycle.

[0071] When push rod 3 moves to the right, the combustion gas in the first cylinder 1a does work, the first piston 2a moves to the right, and the second piston 2b also moves to the right, compressing the oil-air mixture in the second cylinder 1b; when push rod 3 moves to the left, the combustion gas in the second cylinder 1b does work, the second piston 2b moves to the left, and the first piston 2a also moves to the left, compressing the oil-air mixture in the first cylinder 1a; one reciprocating motion of the piston in a piston engine is two strokes, or one cycle. In each stroke, one cylinder is always compressing and the other cylinder is doing work.

[0072] In each stroke, one drive shaft is always driven and transmits power, while the other drive shaft is not under force and rotates freely due to inertia. This alternation ensures that in each stroke, one drive shaft always outputs power.

[0073] In each stroke, one drive shaft is always driven and transmits power, while the other drive shaft is not under force and rotates freely due to inertia. This alternation ensures that in each stroke, one drive shaft always outputs power.

[0074] The specific working principle of the piston engine in this embodiment is as follows, and one cycle of the piston engine includes a first state, a second state, a third state, and a fourth state.

[0075] As shown in Figure 1, the piston engine is in the first state. The first piston 2a has just completed the power stroke and reached the bottom dead center. After scavenging, it has completed the exhaust and intake processes. At the same time, the second piston 2b has completed the compression stroke and reached the top dead center.

[0076] As shown in Figure 4, the piston engine is in the second state. The first cylinder 1a is in the compression stroke. The driving force of the first piston 2a comes from the second piston 2b of the second cylinder 1b. That is, the gas in the second combustion chamber of the second cylinder 1b burns and expands rapidly to do work, pushing the second piston 2b to the left. The second cylinder 1b is in the power stroke. The rapid expansion of the second piston 2b can reduce knocking in the SI combustion in the second cylinder 1b, reduce nitrogen oxides, and improve the emission of unburned hydrocarbons (i.e., UHC) and CO. At this time, the second piston 2b drives the push rod 3 to move to the left, which in turn drives the first piston 2a to move to the left and compresses the gas in the first cylinder 1a. This is the compression stroke. During this process, the rack 31 drives the first rocker gear 4a and the second rocker gear 4b to rotate counterclockwise. Only the second one-way clutch 5b transmits power to make the second drive shaft 6b rotate counterclockwise and output power, but the first one-way clutch 5a does not transmit power. The first drive shaft 6a can only rely on inertia to maintain clockwise rotation.

[0077] As shown in Figure 5, the piston engine is in the third state. The first piston 2a completes the compression stroke and reaches the top dead center, while the second piston 2b completes the power stroke and reaches the bottom dead center. After scavenging, it completes the exhaust and intake processes.

[0078] As shown in Figure 6, the piston engine is in its fourth state. When the first cylinder 1a is in its power stroke, the gas in the first combustion chamber of the first cylinder 1a burns and expands rapidly to do work, pushing the first piston 2a to the right. The rapid expansion of the first piston 2a can reduce knocking in the SI combustion in the first cylinder 1a, reduce nitrogen oxides, and improve the emission of unburned hydrocarbons and CO. At this time, the first piston 2a drives the push rod 3 to move to the right synchronously, which in turn drives the second piston 2b to move to the right and compresses the gas in the second cylinder 1b, which is the compression stroke. The rack 31 drives the first rocker gear 4a and the second rocker gear 4b to rotate clockwise. Only the first one-way clutch 5a transmits power to make the first drive shaft 6a rotate clockwise and output power, but the second one-way clutch 5b does not transmit power. The second drive shaft 6b can only rely on inertia to maintain counterclockwise rotation.

[0079] As shown in Figure 2, the first drive shaft 6a rotates clockwise and alternates between driving and idling, while the synchronous second drive shaft 6b rotates counterclockwise and alternates between idling and driving.

[0080] Then, the first drive shaft 6a and the second drive shaft 6b alternately drive and idle, respectively, to ensure that there is always one drive shaft driving in each stroke, and outputs torque through the first output gear 8a or the second output gear 8b respectively.

[0081] Within one cycle of a piston engine, the piston engine has a variable stroke and compression ratio. The variable compression ratio allows the use of different fuels to enhance the flexibility and adaptability of the piston engine, and can also promote HCCI combustion to ensure higher thermal efficiency (i.e., thermal efficiency of not less than 60%). It can also improve the potential for SI-HCCI conversion through the variable compression ratio.

[0082] This embodiment replaces the complex transmission mechanism composed of crankshaft and other components in the prior art by using a push rod 3 with rack 31 and the 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.

[0083] Furthermore, by pushing the rack 31 on the push rod 3 to drive the corresponding rocker gear to rotate, 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.

[0084] 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.

[0085] 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.

[0086] Of course, in other embodiments, the number of cylinders is not limited to this, and there may be more than two, which will not be described in detail here.

[0087] Furthermore, as shown in Figure 3, meshing coupling gears 7 are respectively provided on the two drive shafts, and the first drive shaft 6a is provided with an output gear 8 for outputting torque, so as to achieve continuous output torque.

[0088] When the first drive shaft 6a is in operation, the power is directly output through the output gear 8 mounted on the first drive shaft 6a. At this time, the first drive shaft 6a rotates clockwise, while the second drive shaft 6b rotates counterclockwise.

[0089] When the first drive shaft 6a is idling, it rotates clockwise, while the second drive shaft 6b transmits power and rotates counterclockwise. This causes the coupling gear on the second drive shaft 6b to rotate counterclockwise, which in turn causes the coupling gear on the first drive shaft 6a to rotate clockwise and transmit power, thereby driving the output gear 8 mounted on the first drive shaft 6a to rotate clockwise and output power.

[0090] Thus, in each stroke as shown in Figure 3, the output gear 8 always outputs power and rotates clockwise.

[0091] Example 2

[0092] Referring to Figures 7 to 11, Embodiment 2 provides a free piston engine. The structure of Embodiment 2 is generally the same as that of Embodiment 1, except that: a double-sided rack is provided on the push rod 3', and two rocker gears are respectively provided on the upper and lower sides of the corresponding push rod 3', and the rotation directions of the two transmission shafts are the same.

[0093] The first rocker gear 4a meshes with the lower rack of the push rod 3', and the second rocker gear 4b meshes with the upper rack of the push rod 3'. This arrangement ensures that the two rocker gears always rotate in opposite directions.

[0094] When push rod 3' moves to the right, the lower rack of push rod 3' pushes the first rocker gear 4a to rotate clockwise, the first one-way clutch 5a locks, and the first drive shaft 6a rotates clockwise and transmits power; at the same time, the upper rack of push rod 3' pushes the second rocker gear 4b to rotate counterclockwise, the second one-way clutch 5b disengages, and the second drive shaft 6b is not under force and rotates clockwise by inertia.

[0095] When push rod 3' moves to the left, the upper rack of push rod 3' pushes the second rocker gear 4b to rotate clockwise, the second one-way clutch 5b locks, and the second drive shaft 6b rotates clockwise and transmits power; at the same time, the lower rack of push rod 3' pushes the first rocker gear 4a to rotate counterclockwise, the first one-way clutch 5a disengages, and the first drive shaft 6a is not under force and rotates clockwise by inertia.

[0096] The specific working principle of this embodiment is as follows:

[0097] As shown in Figure 7, the piston engine is in the first state. The first piston 2a has just completed the power stroke and reached the bottom dead center. After scavenging, it has completed the exhaust and intake processes. At the same time, the second piston 2b has completed the compression stroke and reached the top dead center.

[0098] As shown in Figure 8, the piston engine is in the second state. When the first piston 2a is in the compression stroke, the driving force of the first piston 2a comes from the second piston 2b of the second cylinder 1b. That is, the gas in the second combustion chamber of the second cylinder 1b burns and expands rapidly to do work, pushing the second piston 2b to the left. The second cylinder 1b is in the power stroke. At this time, the second piston 2b drives the push rod 3' to move to the left, which in turn drives the first piston 2a to move to the left and compresses the gas in the first cylinder 1a. This is the compression stroke. During this process, the lower rack of the push rod 3' drives the first rocker gear 4a to rotate counterclockwise, and the upper rack of the push rod 3' drives the second rocker gear 4b to rotate clockwise. Only the second one-way clutch 5b transmits power to make the second drive shaft 6b rotate clockwise, but the first one-way clutch 5a does not transmit power. The first drive shaft 6a can only maintain clockwise rotation by inertia.

[0099] As shown in Figure 9, the piston engine is in the third state. The first piston 2a completes the compression stroke and reaches the top dead center, while the second piston 2b completes the power stroke and reaches the bottom dead center. After scavenging, it completes the exhaust and intake processes.

[0100] As shown in Figure 10, the piston engine is in the fourth state. When the first piston 2a is in the power stroke, the gas in the first combustion chamber of the first cylinder 1a burns and expands rapidly to do work, pushing the first piston 2a to the right. The first cylinder 1a is in the power stroke. At this time, the first piston 2a drives the push rod 3' to the right, which in turn drives the second piston 2b to the right and compresses the gas in the second cylinder 1b, which is the compression stroke. The lower rack of the push rod 3' drives the first rocker gear 4a to rotate clockwise, while the upper rack of the push rod 3' drives the second rocker gear 4b to rotate counterclockwise. Only the first one-way clutch 5a transmits power to make the first drive shaft 6a rotate clockwise, but the second one-way clutch 5b does not transmit power. The second drive shaft 6b can only maintain clockwise rotation by inertia.

[0101] This embodiment replaces the complex transmission mechanism composed of crankshaft and other components in the prior art by setting a push rod 3' with a double-sided rack and the 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.

[0102] Furthermore, by pushing the corresponding rocker gear through 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.

[0103] In another preferred embodiment, as shown in FIG11, a first gear 10a and a second gear 10b are respectively provided on the two transmission shafts. The first gear 10a and the second gear 10b are both meshed with a coupling gear 7 to form a coupling configuration for alternating power transmission. The coupling gear 7 is equipped with a connecting shaft 9, and the connecting shaft 9 is provided with an output gear 8 for outputting torque to achieve continuous torque output.

[0104] In this specific embodiment, the first gear 10a, the second gear 10b, and the coupling gear 7 meshing with the first gear 10a and the second gear 10b constitute an output torque coupling mechanism. The first gear 10a is fixedly connected to the first transmission shaft 6a and rotates clockwise. The second gear 10b is fixedly connected to the second transmission shaft 6b and rotates clockwise. The first gear 10a and the second gear 10b mesh with the coupling gear 7 respectively to realize the power coupling of alternating transmission between the first gear 10a and the second gear 10b, thereby forming a continuous output power. The power is then transmitted through the connecting shaft 9 mounted on the coupling gear 7 to drive the output gear 8 fixed on the connecting shaft 9 to rotate and continuously output torque.

[0105] Of course, in other embodiments, as shown in Figure 2, two transmission shafts can be respectively equipped with output gears 8 for outputting torque, and the first transmission shaft 6a and the second transmission shaft 6b can alternately output power to achieve alternating torque output, which will not be described in detail here.

[0106] Example 3

[0107] Referring to Figures 12 to 17, Embodiment 3 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. The piston engine also includes a transmission assembly, which includes two rocker gears, a one-way clutch cooperating with each rocker gear, and a transmission shaft. The rocker gears are configured to rotate around a fixed axis. The pistons of the two cylinders in each set are connected by a push rod. The two push rods are respectively provided with racks. The two rocker gears mesh with the racks of the two push rods respectively. The rocker gears are connected to the corresponding transmission shafts through the one-way clutches. The rocker gears perform fixed-axis rocker rotation, such as clockwise or counterclockwise rotation, while the transmission shaft rotates in one direction.

[0108] Each cylinder sequentially completes the intake stroke, compression stroke, power stroke, and exhaust stroke, forming a cycle. That is, each cylinder is matched with a piston to form a gas-tight combustion chamber. The piston moves back and forth in its corresponding cylinder to change the volume of the combustion chamber. The piston moves from one end of the cylinder to the other to complete one stroke. There are a total of four strokes forming a cycle, namely the intake stroke, compression stroke, power stroke, and exhaust stroke. Therefore, the piston engine in this embodiment is a four-stroke free piston engine.

[0109] Furthermore, one cylinder's piston is always performing power strokes, simultaneously driving the other three cylinders to complete the intake, compression, and exhaust strokes respectively. The locking directions of the two one-way clutches are set to be opposite to each other, ensuring that one of the two drive shafts is outputting torque while the other is idling. The idling direction of the drive shaft is the same as the transmission rotation direction. That is, in any power stroke, one one-way clutch is always locked, causing the corresponding rocker gear and drive shaft to transmit power, while the other one-way clutch is disengaged, causing the corresponding drive shaft to rotate without load. This ensures that one of the two drive shafts is outputting torque while the other is idling, and the rotation direction of each drive shaft remains unchanged whether it is transmitting power or rotating without load. The one-way engagement characteristic of the one-way clutch allows the drive shaft to continue rotating along the transmission direction and by inertia when unloaded.

[0110] In this embodiment, the racks of the two push rods are single-sided racks and are arranged opposite to each other. The two rocker gears are arranged between the racks of the two push rods and mesh with the two racks one by one. The rotation directions of the two transmission shafts are set to be opposite to each other, and the two transmission shafts are respectively provided with output gears for outputting torque to realize the output torque.

[0111] In specific implementation, the two cylinders in one group are the first cylinder 1a' and the second cylinder 1b', which are symmetrically arranged with a left-right spacing, and the two cylinders in the other group are the third cylinder 1d and the fourth cylinder 1c, which are symmetrically arranged with a left-right spacing. Specifically, the first cylinder 1a', the second cylinder 1b', the third cylinder 1d, and the fourth cylinder 1c are all fixedly mounted on the housing of the piston engine and are stationary.

[0112] The first cylinder 1a' is equipped with a first combustion chamber and a first piston 2a', the second cylinder 1b' is equipped with a second combustion chamber and a second piston 2b', the third cylinder 1d is equipped with a third combustion chamber and a third piston 2d, and the fourth cylinder 1c is equipped with a fourth combustion chamber and a fourth piston 2c. The two push rods are a first push rod and a second push rod, and the racks of the first push rod and the second push rod are a first rack 3a and a second rack 3b, respectively.

[0113] 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 make a left-right reciprocating linear motion together. The third piston 2d and the fourth piston 2c are fixedly connected by the second push rod, so that the third piston 2d, the fourth piston 2c and the second push rod can make a left-right reciprocating linear motion together.

[0114] The two rocker gears are a first rocker gear 4a and a second rocker gear 4b, which are set on the left and right respectively. The two one-way clutches are a first one-way clutch 5a and a second one-way clutch 5b respectively. The two drive shafts are a first drive shaft 6a and a second drive shaft 6b respectively.

[0115] As shown in Figure 16, a first output gear 8a' for outputting torque is mounted on the first drive shaft 6a, and a second output gear 8b' for outputting torque is mounted on the second drive shaft 6b.

[0116] Both the first one-way clutch 5a and the first drive shaft 6a are mounted on the first rocker gear 4a, and the first rocker gear 4a and the first drive shaft 6a are connected by the first one-way clutch 5a. In this embodiment, the first one-way clutch 5a is configured as follows: when the first rocker gear 4a rotates clockwise, the first one-way clutch 5a locks and transmits power; when the first rocker gear 4a rotates counterclockwise, the first one-way clutch 5a disengages, allowing the first drive shaft 6a to rotate clockwise freely.

[0117] The second one-way clutch 5b and the second drive shaft 6b are both mounted on the second rocker gear 4b, and the second rocker gear 4b and the second drive shaft 6b are connected by the second one-way clutch 5b. In this embodiment, the second one-way clutch 5b is configured as follows: when the second rocker gear 4b rotates counterclockwise, the second one-way clutch 5b locks and transmits power; when the second rocker gear 4b rotates clockwise, the second one-way clutch 5b disengages, allowing the second drive shaft 6b to rotate counterclockwise.

[0118] The first rocker gear 4a meshes with the first rack 3a and the second rack 3b respectively, and the second rocker gear 4b also meshes with the first rack 3a and the second rack 3b respectively.

[0119] The specific working principle of the piston engine in this embodiment is as follows, including the first stroke stage as shown in Figure 12, the second stroke stage as shown in Figure 13, the third stroke stage as shown in Figure 14, and the fourth stroke stage as shown in Figure 15.

[0120] As shown in Figure 12, when the first piston 2a' is in the intake stroke, the driving force in the first stroke stage comes from the fourth piston 2c of the fourth cylinder 1c, that is, the fuel in the fourth cylinder 1c burns and expands to do work, which is the power stroke, and pushes the fourth piston 2c to move to the left, which in turn pushes the second rack 3b of the second push rod to move to the left, and then drives the first rocker gear 4a and the second rocker gear 4b to rotate clockwise, which in turn drives the first rack 3a of the first push rod to move to the right; moreover, the first push rod drives the first piston 2a' to move to the right, and the volume in the first cylinder 1a' increases, so as to draw in gas (such as air) or intake air without high pressure assistance, which is the intake stroke; the first push rod pushes the second piston 2b' to move to the right, compressing the gas in the second cylinder 1b', which is the compression stroke; the second push rod pushes the third piston 2d to move to the left, and discharges the exhaust gas in the third cylinder 2d, which is the exhaust stroke.

[0121] During the first stroke, the first cylinder 1a' is in the intake stroke, the second cylinder 1b' is in the compression stroke, the fourth cylinder 1c is in the power stroke, and the third cylinder 1d is in the exhaust stroke. When the fourth cylinder 1c performs its power stroke, the fourth piston 2c pushes the second rack 3b of the second push rod to the left, thereby driving the first rocker gear 4a and the second rocker gear 4b to rotate clockwise. The first rocker gear 4a drives the first drive shaft 6a to rotate clockwise and transmits power through the one-way clutch 5a. At the same time, the one-way clutch 5b is disengaged, and the second rocker gear 4b rotates relative to the second drive shaft 6b without forming a transmission connection. Therefore, the second drive shaft 6b rotates counterclockwise. In short, the power output by the fourth piston 2c is transmitted to the first drive shaft 6a through the first rocker gear 4a and the one-way clutch 5a, driving the first drive shaft 6a to rotate clockwise, while the second drive shaft 6b rotates counterclockwise.

[0122] As shown in Figure 13, when the first piston 2a' is in the compression stroke, the driving force in the second stroke stage comes from the second piston 2b' of the second cylinder 1b', that is, the fuel in the second cylinder 1b' burns and expands to do work, which is the power stroke, and pushes the second piston 2b' to the left. The second piston 2b' pushes the first rack 3a of the first push rod to the left, driving the first rocker gear 4a and the second rocker gear 4b to rotate counterclockwise, which in turn drives the second rack 3b of the second push rod to the right; moreover, the first push rod drives the first piston 2a' to the left and compresses the gas in the first cylinder 2a, which is the compression stroke; the second push rod drives the fourth piston 2c to the right and discharges the exhaust gas in the fourth cylinder 2c, which is the exhaust stroke; the second rack 3b drives the third piston 2d to the right, the volume in the third cylinder 1d increases, and gas is drawn in, which is the intake stroke.

[0123] During the second stroke, the first cylinder 1a' is in the compression stroke, the second cylinder 1b' is in the power stroke, the fourth cylinder 1c is in the exhaust stroke, and the third cylinder 1d is in the intake stroke. When the second cylinder 1b' performs its power stroke, the second piston 2b' pushes the first rack 3a of the first push rod to the left, thereby driving the first rocker gear 4a and the second rocker gear 4b to rotate counterclockwise. The second rocker gear 4b drives the second drive shaft 6b to rotate counterclockwise and transmits power through the one-way clutch 5b. At the same time, the one-way clutch 5a is disengaged, and the first rocker gear 4a and the first drive shaft 6a rotate relative to each other without forming a transmission connection. Therefore, the first drive shaft 6a rotates clockwise without load. In short, the power output by the second piston 2b' is transmitted to the second drive shaft 6b through the second rocker gear 4b and the one-way clutch 5b, driving the second drive shaft 6b to rotate counterclockwise, while the first drive shaft 6a rotates clockwise without load.

[0124] As shown in Figure 14, when the first piston 2a' is in the power stroke, the driving force in the third stroke stage 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, and pushes the first piston 2a' to move to the right, pushing the first rack 3a of the first push rod to move to the right, which in turn drives the first rocker gear 4a and the second rocker gear 4b to rotate clockwise, which in turn drives the second rack 3b of the second push rod to move to the left; moreover, the first push rod drives the second piston 2b' to move to the right, venting the exhaust gas in the second cylinder 1b', which is the exhaust stroke; the second push rod drives the fourth piston 2c to move to the left, increasing the volume in the fourth cylinder 1c and drawing in gas, which is the intake stroke; the second push rod drives the third piston 2d to move to the left, compressing the gas in the third cylinder 1d, which is the compression stroke.

[0125] In the third stroke, the first cylinder 1a' is in the power stroke, the second cylinder 1b' is in the exhaust stroke, the fourth cylinder 1c is in the intake stroke, and the third cylinder 1d is in the compression stroke. When the first cylinder 1a' is performing its power stroke, the first piston 2a' pushes the first rack 3a of the first push rod to the right, thereby driving the first rocker gear 4a and the second rocker gear 4b to rotate clockwise. The first rocker gear 4a drives the first drive shaft 6a to rotate clockwise and transmits power through the one-way clutch 5a. At the same time, the one-way clutch 5b is disengaged, and the second rocker gear 4b rotates relative to the second output gear 8b' without forming a transmission connection. Therefore, the second drive shaft 6b rotates counterclockwise. In short, the power output by the first piston 2a' is transmitted to the first drive shaft 6a through the first rocker gear 4a and the one-way clutch 5a, driving the first drive shaft 6a to rotate clockwise, while the second drive shaft 6b rotates counterclockwise.

[0126] As shown in Figure 15, when the first piston 2a' is in the exhaust stroke, the driving force of the fourth stroke stage comes from the third piston 2d of the third cylinder 1d. That is, the fuel in the third cylinder 1d burns and expands to do work, which is the power stroke. This pushes the third piston 2d to move to the right. The third piston 2d pushes the second rack 3b of the second push rod to move to the right, driving the first rocker gear 4a and the second rocker gear 4b to rotate counterclockwise, which in turn drives the first rack 3a of the first push rod to move to the left. Moreover, the first push rod drives the first piston 2a' to move to the left, venting the exhaust gas in the first cylinder 1a'. This is the exhaust stroke. The first push rod drives the second piston 2b' to move 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 fourth piston 2c to move to the right, compressing the gas in the fourth cylinder 2c. This is the compression stroke.

[0127] In the fourth stroke, the first cylinder 1a' is in the exhaust stroke, the second cylinder 1b' is in the intake stroke, the fourth cylinder 1c is in the compression stroke, and the third cylinder 1d is in the power stroke. When the third cylinder 1d performs its power stroke, the third piston 2d pushes the second rack 3b of the second push rod to the right, thereby driving the first rocker gear 4a and the second rocker gear 4b to rotate counterclockwise. The second rocker gear 4b drives the second drive shaft 6b to rotate counterclockwise and transmits power through the one-way clutch 5b. At the same time, the one-way clutch 5a is disengaged, and the first rocker gear 4a and the first drive shaft 6a rotate relative to each other without forming a transmission connection. Therefore, the first drive shaft 6a rotates clockwise without load. In short, the power output by the third piston 2d is transmitted to the second drive shaft 6b through the second rocker gear 4b and the one-way clutch 5b, driving the second drive shaft 6b to rotate counterclockwise, while the first drive shaft 6a rotates clockwise without load.

[0128] The above four strokes constitute a complete working cycle of a piston engine, that is, the cylinder sequentially enters the intake stroke, compression stroke, power stroke and exhaust stroke, repeating the cycle repeatedly; in each stroke, there is always one cylinder in intake, another cylinder in compression, a third cylinder in power, and a fourth cylinder in exhaust.

[0129] In addition, the power generated by the cylinders in the first and third strokes is output through the first drive shaft 6a, which rotates clockwise, while the second drive shaft 6b rotates counterclockwise.

[0130] The power generated by the cylinders in the second and fourth strokes is output through the second drive shaft 6b, which rotates counterclockwise, while the first drive shaft 6a rotates clockwise.

[0131] In summary, the first drive shaft 6a can maintain clockwise rotation and alternate between driving and idling, and the second drive shaft 6b can also maintain counterclockwise rotation and alternate between idling and driving. In this way, the first drive shaft 6a and the second drive shaft 6b alternate between driving and idling, and there is always one drive shaft driving in each stroke, and the output is respectively through the first output gear 8a' or the second output gear 8b'.

[0132] In one 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 not less than 60%). It can also improve the potential for SI-HCCI conversion through the variable compression ratio.

[0133] 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 rotational motion by using a pushrod with a rack to drive a corresponding rocker gear. 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.

[0134] 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.

[0135] In this embodiment, the lever arm of the push rod force on the drive shaft is equal to the radius of the rocker gear. 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.

[0136] Furthermore, in this embodiment, the four cylinders work together in a coordinated manner to achieve a four-stroke cycle. The two pushrods are arranged in parallel, with a rocker gear in the middle, meshing with the racks to ensure motion coupling between the two racks via the rocker gear. 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 expel 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 enabling a higher effective compression ratio, 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.

[0137] Moreover, when the piston 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 is around bottom dead center, the lever arm of the push rod does not decrease, and the output power decays less, thus achieving small output power fluctuations.

[0138] 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.

[0139] Of course, in other embodiments, a coupling mechanism may be provided between the two drive shafts to couple the power of the two drive shafts, ensuring that the output rotation direction remains unchanged and that the output rotational power is continuous and uninterrupted.

[0140] As shown in Figure 17, when the first rocker gear 4a and the second rocker gear 4b rotate clockwise, the first drive shaft 6a rotates clockwise, and the power is directly output through the output gear 8', so that the output gear 8' rotates clockwise and outputs torque. At the same time, the second drive shaft 6b rotates counterclockwise. When the first rocker gear 4a and the second rocker gear 4b rotate counterclockwise, the first drive shaft 6a rotates clockwise, the second drive shaft 6b rotates counterclockwise and transmits power, and drives the second coupling gear 7b to rotate counterclockwise, synchronously driving the first coupling gear 7a to rotate clockwise and transmit power. The first coupling gear 7a drives the output gear 8' to rotate clockwise and output power. In this way, the output gear 8' can continuously output power and torque and maintain clockwise rotation.

[0141] Example 4

[0142] Referring to Figures 18 to 22, Embodiment 4 provides a free piston engine. Embodiment 4 and Embodiment 3 have largely the same structure, except that: the rack of the first push rod is a double-sided rack 3a', and the rack of the second push rod is a single-sided rack 3b'; the first rocker gear 4a is disposed between the two push rods and meshes with the racks of the two push rods respectively; the second rocker gear 4b is disposed on the side of the double-sided rack 3a' away from the single-sided rack 3b' and meshes with the double-sided rack 3a'; when the first rocker gear 4a rotates clockwise, the second rocker gear 4b rotates counterclockwise. The first one-way clutch 5a is configured such that when the first rocker gear 4a rotates clockwise, the first one-way clutch 5a locks and transmits power; when the first rocker gear 4a rotates counterclockwise, the first one-way clutch 5a disengages, allowing the first drive shaft 6a to rotate clockwise freely. The second one-way clutch 5b is configured such that when the second rocker gear 4b rotates clockwise, the second one-way clutch 5b locks and transmits power; when the second rocker gear 4b rotates counterclockwise, the second one-way clutch 5b disengages, allowing the second drive shaft 6b to rotate clockwise freely. Since both drive shafts rotate in the same direction, this arrangement shortens the cylinder axis length.

[0143] In this specific embodiment, as shown in FIG22, a first gear 9a and a second gear 9b are respectively provided on the two transmission shafts. The first gear 9a and the second gear 9b are both meshed with a coupling gear 10 to form a coupling mechanism for alternating power transmission. The coupling gear 10 is equipped with a connecting shaft, and the connecting shaft is provided with an output gear 8' for outputting torque.

[0144] The specific working principle of the piston engine in this embodiment is as follows, including the first stroke stage as shown in Figure 18, the second stroke stage as shown in Figure 19, the third stroke stage as shown in Figure 20, and the fourth stroke stage as shown in Figure 21.

[0145] As shown in Figure 18, when the first piston 2a' is in the intake stroke, the driving force in the first stroke stage comes from the fourth piston 2c of the fourth cylinder 1c. That is, the fuel in the fourth cylinder 1c burns and expands to do work, which is the power stroke. This pushes the fourth piston 2c to the left, which in turn pushes the single-sided rack 3b' of the second push rod to the left. Then, it drives the first rocker gear 4a to rotate clockwise, which in turn drives the double-sided rack 3a' of the first push rod to move to the right. Then, the double-sided rack 3a' drives the second rocker gear 4b to rotate counterclockwise. Moreover, the first push rod drives the first piston 2a' to move to the right, which increases the volume in the first cylinder 1a' and draws in gas, which is the intake stroke. The first push rod pushes the second piston 2b' to move to the right, compressing the gas in the second cylinder 1b', which is the compression stroke. The second push rod pushes the third piston 2d to the left, which discharges the exhaust gas in the third cylinder 2d, which is the exhaust stroke.

[0146] During the first stroke, the first cylinder 1a' is in the intake stroke, the second cylinder 1b' is in the compression stroke, the fourth cylinder 1c is in the power stroke, and the third cylinder 1d is in the exhaust stroke. When the fourth cylinder 1c performs its power stroke, the fourth piston 2c pushes the single-sided rack 3b' of the second push rod to the left, thereby driving the first rocker gear 4a to rotate clockwise. The first rocker gear 4a drives the first drive shaft 6a to rotate clockwise and transmits power through the one-way clutch 5a. At the same time, the double-sided rack 3a' drives the second rocker gear 4b to rotate counterclockwise. The one-way clutch 5b is disengaged, and the second rocker gear 4b rotates relative to the second drive shaft 6b without forming a transmission connection. Therefore, the second drive shaft 6b rotates clockwise without any connection. In short, the power output by the fourth piston 2c is transmitted to the first drive shaft 6a through the first rocker gear 4a and the one-way clutch 5a, driving the first drive shaft 6a to rotate clockwise, while the second drive shaft 6b rotates clockwise without any connection.

[0147] As shown in Figure 19, when the first piston 2a' is in the compression stroke, the driving force in the second stroke stage comes from the second piston 2b' of the second cylinder 1b', that is, the fuel in the second cylinder 1b' burns and expands to do work, which is the power stroke, and pushes the second piston 2b' to the left. The second piston 2b' pushes the double-sided rack 3a' of the first push rod to the left, driving the first rocker gear 4a to rotate counterclockwise. Simultaneously, the double-sided rack 3a' drives the second rocker gear 4b to rotate clockwise, and the first rocker gear 4a drives the single-sided rack 3b' of the second push rod to the right. Moreover, the first push rod drives the first piston 2a' to the left and compresses the gas in the first cylinder 2a, which is the compression stroke. The second push rod drives the fourth piston 2c to the right and discharges the exhaust gas in the fourth cylinder 2c, which is the exhaust stroke. The single-sided rack 3b' drives the third piston 2d to the right, the volume in the third cylinder 1d increases, and gas is drawn in, which is the intake stroke.

[0148] During the second stroke, the first cylinder 1a' is in the compression stroke, the second cylinder 1b' is in the power stroke, the fourth cylinder 1c is in the exhaust stroke, and the third cylinder 1d is in the intake stroke. When the second cylinder 1b' is performing its power stroke, the second piston 2b' pushes the double-sided rack 3a' of the first push rod to the left, thereby driving the first rocker gear 4a to rotate counterclockwise. The second rocker gear 4b drives the second drive shaft 6b to rotate counterclockwise and transmits power through the one-way clutch 5b. At the same time, the double-sided rack 3a' drives the first rocker gear 4a to rotate counterclockwise. The one-way clutch 5a is in the disengaged state, and the first rocker gear 4a and the first drive shaft 6a rotate relative to each other without forming a transmission connection. Therefore, the first drive shaft 6a rotates clockwise without load. In short, the power output by the second piston 2b' is transmitted to the second drive shaft 6b through the second rocker gear 4b and the one-way clutch 5b, driving the second drive shaft 6b to rotate clockwise, while the first drive shaft 6a rotates clockwise without load.

[0149] As shown in Figure 20, when the first piston 2a' is in the power stroke, the driving force in the third stroke stage 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, and pushes the first piston 2a' to move to the right, pushing the double-sided rack 3a' of the first push rod to move to the right, which in turn drives the first rocker gear 4a to rotate clockwise, which in turn drives the single-sided rack 3b' of the second push rod to move to the left. Then the double-sided rack 3a' drives the second rocker gear 4b to rotate counterclockwise; moreover, the first push rod drives the second piston 2b' to move to the right, venting the exhaust gas in the second cylinder 1b', which is the exhaust stroke; the second push rod drives the fourth piston 2c to move to the left, increasing the volume in the fourth cylinder 1c and drawing in gas, which is the intake stroke; the second push rod drives the third piston 2d to move to the left, compressing the gas in the third cylinder 1d, which is the compression stroke.

[0150] In the third stroke, the first cylinder 1a' is in the power stroke, the second cylinder 1b' is in the exhaust stroke, the fourth cylinder 1c is in the intake stroke, and the third cylinder 1d is in the compression stroke. When the first cylinder 1a' is performing its power stroke, the first piston 2a' pushes the double-sided rack 3a' of the first push rod to the right, thereby driving the first rocker gear 4a to rotate clockwise. The first rocker gear 4a drives the first drive shaft 6a to rotate clockwise and transmits power through the one-way clutch 5a. At the same time, the double-sided rack 3a' drives the second rocker gear 4b to rotate counterclockwise. The one-way clutch 5b is in the disengaged state, and the second rocker gear 4b rotates relative to the second output gear 8b' without forming a transmission connection. Therefore, the second drive shaft 6b rotates clockwise without any transmission. In short, the power output by the first piston 2a' is transmitted to the first drive shaft 6a through the first rocker gear 4a and the one-way clutch 5a, driving the first drive shaft 6a to rotate clockwise, while the second drive shaft 6b rotates clockwise without any transmission.

[0151] As shown in Figure 21, when the first piston 2a' is in the exhaust stroke, the driving force of the fourth stroke stage comes from the third piston 2d of the third cylinder 1d, that is, the fuel in the third cylinder 1d burns and expands to do work, which is the power stroke, and pushes the third piston 2d to the right. The third piston 2d pushes the single-sided rack 3b' of the second push rod to the right, driving the first rocker gear 4a to rotate counterclockwise, and the first rocker gear 4a drives the double-sided rack 3a' of the first push rod to the left, thereby driving the second rocker gear 4b to rotate clockwise; moreover, the first push rod drives the first piston 2a' to the left, venting the exhaust gas in the first cylinder 1a', which is the exhaust stroke; the first push rod drives the second piston 2b' to the left, increasing the volume in the second cylinder 1b' and drawing in gas, which is the intake stroke; the second push rod drives the fourth piston 2c to the right, compressing the gas in the fourth cylinder 2c, which is the compression stroke.

[0152] In the fourth stroke, the first cylinder 1a' is in the exhaust stroke, the second cylinder 1b' is in the intake stroke, the fourth cylinder 1c is in the compression stroke, and the third cylinder 1d is in the power stroke. When the third cylinder 1d is performing power, the third piston 2d pushes the single-sided rack 3b' of the second push rod to move to the right, thereby driving the first rocker gear 4a to rotate counterclockwise. The first push rod drives the second rocker gear 4b to rotate clockwise. The second rocker gear 4b drives the second transmission shaft 6b to rotate clockwise and transmit power through the one-way clutch 5b. At the same time, the double-sided rack 3a' drives the first rocker gear 4a to rotate counterclockwise. The one-way clutch 5a is in the disengaged state. The first rocker gear 4a and the first transmission shaft 6a rotate relative to each other but do not form a transmission connection. Therefore, the first transmission shaft 6a rotates clockwise without load. In short, the power output by the third piston 2d is transmitted to the second drive shaft 6b through the second rocker gear 4b and the one-way clutch 5b, driving the second drive shaft 6b to rotate clockwise, while the first drive shaft 6a rotates clockwise.

[0153] In summary, the first drive shaft 6a can maintain clockwise rotation and alternate between driving and idling, and the second drive shaft 6b can also maintain clockwise rotation and alternate between idling and driving. Thus, the first drive shaft 6a and the second drive shaft 6b alternate between driving and idling, ensuring that one drive shaft is always in operation during each stroke, and outputting torque clockwise through either the first output gear 8a' or the second output gear 8b'. Of course, in other embodiments, output gears for outputting torque can also be provided on the two drive shafts as shown in Figure 16.

[0154] As shown in Figure 22, when the first rocker gear 4a rotates clockwise and the second rocker gear 4b rotates counterclockwise, the first drive shaft 6a rotates clockwise, driving the first gear 9a to rotate clockwise and then driving the output gear 8' to rotate counterclockwise to output power. Simultaneously, the second drive shaft 6b rotates clockwise without load. When the first rocker gear 4a rotates counterclockwise and the second rocker gear 4b rotates clockwise, the first drive shaft 6a rotates clockwise without load, and the second drive shaft 6b rotates clockwise to transmit power, driving the second gear 9b to rotate clockwise and then driving the output gear 8' to rotate counterclockwise to output power. Simultaneously, the first drive shaft 6b rotates clockwise without load. This ensures that the output gear 8' continuously outputs power and torque while maintaining counterclockwise rotation.

[0155] Example 5

[0156] Example 5 provides a free piston engine. The structure of Example 5 is generally the same as that of Example 3, 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; the two rocker gears are both set on the rack side of the two push rods; and the rotation directions of the two transmission shafts are set to be opposite to each other.

[0157] 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 two rocker gears are arranged on the same side of the two push rods, and the two rocker gears mesh 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.

[0158] Of course, in other embodiments, the gears of the two racks can also be independent of each other, and the gears of the two rocker gears are wider to overcome the gap between the two racks, thereby ensuring that the two rocker gears mesh with the two racks one by one.

[0159] 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, said cylinder bank including two opposing cylinders, characterized in that: It also includes a transmission unit; The transmission unit includes two rocker gears, a one-way clutch and a transmission shaft that cooperate with each rocker gear, and the rocker gears are configured to rotate on a fixed axis. The pistons of the two cylinders in the cylinder group are connected by push rods. A rack is provided on the push rods. The rocker gear meshes with the rack, and the rocker gear is connected to the corresponding drive shaft through the one-way clutch.

2. The free piston engine according to claim 1, characterized in that: The cylinder assembly is set in one group; all the rocker gears mesh with the rack; Each linear reciprocating motion of the piston corresponds to two strokes; in each stroke, one cylinder is compressing and the other cylinder is doing work; one linear reciprocating motion of the piston forms a cycle, and the locking directions of the two one-way clutches are set to be opposite to each other, so as to ensure that the two drive shafts alternately output torque and idle within the two strokes of one reciprocating motion, and the idle direction of the two drive shafts is the same as the transmission rotation direction.

3. The free piston engine according to claim 2, characterized in that: The rack is a single-sided rack, and the two rocker gears are both located on the same side of the corresponding push rod; the rotation directions of the two drive shafts are set to be opposite to each other.

4. The free piston engine according to claim 2, characterized in that: The two rocker gears are spaced apart.

5. The free piston engine according to claim 3, characterized in that: Each of the two drive shafts is equipped with an output gear for outputting torque, so as to achieve alternating torque output.

6. The free piston engine according to claim 3, characterized in that: Two drive shafts are equipped with meshing coupling gears, and one of the drive shafts is equipped with an output gear for outputting torque, so as to achieve continuous output torque.

7. The free piston engine according to claim 2, characterized in that: The rack is a double-sided rack, with two rocker gears respectively located on both sides of the corresponding push rod; the two drive shafts rotate in the same direction.

8. The free piston engine according to claim 7, characterized in that: Each of the two drive shafts is equipped with an output gear for outputting torque, so as to achieve alternating torque output.

9. The free piston engine according to claim 7, characterized in that: Two drive shafts are respectively equipped with a first gear and a second gear, both of which mesh with a coupling gear to form a coupling configuration for alternating power transmission; the coupling gear is fitted with a connecting shaft, and the connecting shaft is equipped with an output gear for outputting torque to achieve continuous torque output.

10. The free piston engine according to claim 1, characterized in that: The number of cylinder groups is two; The pistons of the two sets of cylinders are connected by corresponding push rods; each push rod is equipped with a rack, one of which is a rocker gear that meshes with the racks of both push rods, and the other is a rocker gear that meshes with the rack of at least one push rod. Each cylinder sequentially completes the intake stroke, compression stroke, power stroke, and exhaust stroke, forming a cycle. There is always one cylinder whose piston is performing power, synchronously driving the other three cylinders to complete their respective intake, compression, and exhaust strokes. The locking directions of the two one-way clutches are set to be opposite to each other, ensuring that one of the two drive shafts is outputting torque while the other is idling, and the idling direction of the drive shaft is the same as the transmission rotation direction.

11. The free piston engine according to claim 10, 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.

12. The free piston engine according to claim 10, characterized in that: The racks of the two push rods are single-sided racks and are arranged opposite to each other; the two rocker gears are both arranged between the racks of the two push rods, and the two rocker gears mesh with the two racks one by one; the rotation directions of the two drive shafts are set to be opposite to each other.

13. The free piston engine according to claim 12, characterized in that: Each of the two drive shafts is equipped with an output gear for outputting torque.

14. The free piston engine according to claim 12, characterized in that: A coupling mechanism is provided between the two drive shafts to couple the power of the two drive shafts, ensuring that the output rotation direction remains unchanged and that the output rotational power is continuous and uninterrupted.

15. The free piston engine according to claim 10, characterized in that: One of the push rods has a single-sided rack, and the other push rod has a double-sided rack; one rocker gear is located between the two push rods and meshes with the racks of the two push rods respectively; another rocker gear is located on the side of the double-sided rack away from the single-sided rack and meshes with the double-sided rack; the two drive shafts rotate in the same direction.

16. The free piston engine according to claim 15, characterized in that: Each of the two drive shafts is equipped with an output gear for outputting torque.

17. The free piston engine according to claim 15, characterized in that: A coupling mechanism is provided between the two drive shafts to couple the power of the two drive shafts, ensuring that the output rotation direction remains unchanged and that the output rotational power is continuous and uninterrupted.

18. The free piston engine according to claim 10, 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 set on the same side, and the two rocker gears are set on the rack side of the two push rods, with the two rocker gears meshing with the two racks one by one; the rotation directions of the two drive shafts are set to be opposite to each other.

19. The free piston engine according to claim 18, 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.

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