Double-crankshaft internal combustion engine and vehicle having the same

Abstract

This invention provides a double-crankshaft internal combustion engine and a vehicle having the same. The double-crankshaft internal combustion engine includes: a first cylinder assembly; and a second cylinder assembly, the first and second cylinder assemblies being arranged mirror images of each other. The first cylinder assembly includes: a first piston assembly mounted within a first cylinder liner; and a first reciprocating connecting rod coupler mounted within a guide in the first cylinder block, one end of which is hinged to the first piston assembly, and the other end connected to a first crank structure. The second cylinder assembly includes: a second piston assembly mounted within a second cylinder liner, and the second piston assembly reciprocates within the second cylinder liner. The first and second piston assemblies operate synchronously, and the first and second crank structures are arranged in opposite directions of motion. This invention solves the problem of significant sliding friction loss due to piston-side thrust in traditional internal combustion engine crank-connecting rod mechanisms, which consequently affects effective thermal efficiency.

Description

Technical Field

[0001] This invention relates to the field of internal combustion engine technology, and more specifically, to a double crankshaft internal combustion engine and a vehicle having the same. Background Technology

[0002] With the continuous advancement of the global dual-carbon strategy, countries are vigorously developing low-pollution, energy-saving clean fuel internal combustion engines. Improving effective thermal efficiency is the direction of development, and reducing friction work is one of the ways to improve effective thermal efficiency. In the traditional crank-connecting rod mechanism, the piston and cylinder generate lateral thrust during the movement, which causes a large sliding friction loss.

[0003] There is currently no effective solution to the aforementioned technical problems. Summary of the Invention

[0004] The main objective of this invention is to provide a double crankshaft internal combustion engine and a vehicle having the same, in order to solve the technical problem that the traditional internal combustion engine crankshaft connecting rod mechanism suffers from large sliding friction loss due to piston-side thrust during operation, which in turn affects the effective thermal efficiency.

[0005] To achieve the above objectives, according to one aspect of the present invention, a double-crankshaft internal combustion engine is provided, comprising: a first cylinder assembly; and a second cylinder assembly, the first cylinder assembly and the second cylinder assembly being arranged in a mirror image arrangement; the first cylinder assembly comprising: a first piston assembly, the first piston assembly being mounted within a first cylinder liner and reciprocating within the first cylinder liner; and a first reciprocating connecting rod coupler, the first reciprocating connecting rod coupler being mounted within a first cylinder block guide, one end of the first reciprocating connecting rod coupler being hinged to the first piston assembly, and the other end of the first reciprocating connecting rod coupler being connected to a first crank structure; the second cylinder assembly comprising: a second piston assembly, the second piston assembly being mounted within a second cylinder liner and reciprocating within the second cylinder liner; and a second reciprocating connecting rod coupler, the second reciprocating connecting rod coupler being mounted within a second cylinder block guide, one end of the second reciprocating connecting rod coupler being hinged to the second piston assembly, and the other end of the second reciprocating connecting rod coupler being connected to a second crank structure; wherein the first piston assembly and the second piston assembly operate synchronously, and the first crank structure and the second crank structure are arranged in opposite directions of motion.

[0006] Furthermore, the second reciprocating link coupling body and the first reciprocating link coupling body are interlocked, and a sliding pair is formed between the second reciprocating link coupling body and the first reciprocating link coupling body.

[0007] Furthermore, the first piston assembly includes: a first piston body, which reciprocates within a first cylinder liner; and a first reciprocating connecting rod, one end of which is hinged to the first piston body via a first piston pin, and the other end of which is connected to a first reciprocating connecting rod coupling body.

[0008] Further, the first crank structure includes: a first connecting rod, one end of which is hinged to a first reciprocating connecting rod coupling body via a first connecting rod pin; a first crank, one end of which is hinged to the other end of the first connecting rod via a first crank pin, and the other end of the first crank is connected to a first synchronous gear; wherein, the ratio of the length L1 of the first connecting rod to the crank radius R1 of the first crank satisfies: 3.0≤L1 / R2≤4.5.

[0009] Furthermore, the second piston assembly includes: a second piston body, which reciprocates within the second cylinder liner; and a second reciprocating connecting rod, one end of which is hinged to the second piston body via a second piston pin, and the other end of which is connected to a second reciprocating connecting rod coupling body.

[0010] Furthermore, the first piston body and the second piston body move synchronously and in the same direction.

[0011] Furthermore, the second crank structure includes: a second connecting rod, one end of which is hinged to a second reciprocating connecting rod coupling body via a second connecting rod pin; a second crank, one end of which is hinged to the other end of the second connecting rod via a second crank pin, and the other end of the second crank is connected to a second synchronous gear; wherein, the ratio of the length L2 of the second connecting rod to the crank radius R2 of the second crank satisfies: 3.0≤L1 / R2≤4.5.

[0012] Furthermore, the second reciprocating connecting rod coupler is provided with a second sliding pair surface, and the first reciprocating connecting rod coupler is provided with a first sliding pair surface. The first sliding pair surface and the second sliding pair surface are fitted together to form a sliding pair. The sliding pair is used to allow a small relative sliding displacement between the second reciprocating connecting rod coupler and the first reciprocating connecting rod coupler to adapt to machining errors or deformation differences.

[0013] Furthermore, the second sliding joint surface is located between the first sliding joint surfaces on both sides, and the second sliding joint surface protrudes from the first sliding joint surface.

[0014] According to another aspect of the present invention, a vehicle is provided having a double-crankshaft internal combustion engine, wherein the double-crankshaft internal combustion engine is the aforementioned double-crankshaft internal combustion engine.

[0015] By applying the technical solution of this invention, the effective cancellation of piston lateral thrust is achieved through the mirror-symmetrical arrangement and synchronous operation of the first and second cylinder assemblies. The first and second piston assemblies reciprocate within their respective cylinder liners. The motion of the piston assemblies is transmitted to the first and second crank structures respectively via the first and second reciprocating connecting rod couplers. The first and second crank structures are arranged in opposite directions of motion. This mirror-symmetrical and reverse transmission mechanism balances the lateral forces generated by the two cylinders during operation, thereby significantly reducing sliding friction losses between the piston and cylinder liner and improving the effective thermal efficiency of the internal combustion engine. Attached Figure Description

[0016] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 A schematic diagram of an embodiment of a double-crankshaft internal combustion engine according to the present invention is shown; Figure 2 A schematic diagram of a side thrust cancellation structure according to an embodiment of a double-crankshaft internal combustion engine is shown.

[0017] The above figures include the following reference numerals: 1. First cylinder assembly; 11. First piston assembly; 101. First cylinder liner; 102. First piston body; 103. First piston pin; 104. First reciprocating connecting rod; 105. First cylinder block guide; 106. First reciprocating connecting rod coupler; 1061. First sliding pair surface; 10. First crank structure; 107. First connecting rod pin; 108. First connecting rod; 109. First crank pin; 110. First crank; 111. First synchronizing gear; 2. Second cylinder assembly; 21. Second piston assembly; 201. Second cylinder liner; 202. Second piston body; 203. Second piston pin; 204. Second reciprocating connecting rod; 205. Second cylinder block guide; 206. Second reciprocating connecting rod coupler; 2061. Second sliding pair surface; 20. Second crank structure; 207. Second connecting rod pin; 208. Second connecting rod; 209. Second crank pin; 210. Second crank; 211. Second synchronous gear. Detailed Implementation

[0018] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0019] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0020] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such terms can be used interchangeably where appropriate so that the embodiments of this application described herein can be implemented, for example, in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0021] Exemplary embodiments according to this application will now be described in more detail with reference to the accompanying drawings. However, these exemplary embodiments may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that these embodiments are provided so that the disclosure of this application is thorough and complete, and that the concept of these exemplary embodiments is fully conveyed to those skilled in the art. In the drawings, for clarity, the thickness of layers and regions may be exaggerated, and the same reference numerals are used to denote the same devices, and therefore their description will be omitted.

[0022] The prior art discloses the following structures: CN106285994A discloses a free-piston internal combustion engine and an internal combustion generator, which uses a rack and pinion mechanism to convert the reciprocating motion of the piston into rotational motion, thus solving the defects of unstable compression ratio and unstable torque of the internal combustion engine.

[0023] CN2083198U discloses a crank-connecting rod mechanism for an internal combustion engine, which features two connecting rods and two parallel crankshafts connected to the same piston pin. This mechanism overcomes the lateral forces generated by the crank-connecting rod mechanism in traditional structures, essentially eliminates reactive friction, and reduces energy consumption.

[0024] CN108561225A discloses a method for improving the effective thermal efficiency of an engine and the power transmission mechanism prepared therefrom. It discloses a double crank connecting rod mechanism that significantly reduces the lateral thrust between the piston and the cylinder liner, thereby reducing piston friction and vibration.

[0025] CN108518279A discloses a method for improving the effective thermal efficiency of an engine and a power transmission mechanism thereof, which is an embodiment of CN108561225A.

[0026] CN223164593U, a double-crank piston cylinder mechanism for engines and compressors, discloses a scheme for eliminating piston side thrust using a double connecting rod and double crankshaft, which solves the problem of insufficient constraints in an implementation scheme of CN108561225A.

[0027] However, the aforementioned patents still have certain drawbacks: CN106285994A abandons the crank-connecting rod mechanism and uses a rack to convert the linear motion of the piston into the rotational motion of the gear disk, resulting in poor reliability. CN2083198U, CN110621856A, and CN223164593U all suffer from over-constraint issues, where even minor manufacturing errors or deformation inconsistencies can lead to the risk of the mechanism jamming. Patent CN108561225A suffers from insufficient constraint, as the T-shaped component cannot maintain a stable position. Patent CN108518279A solves both the over-constraint and insufficient constraint problems; however, these patent solutions all add a connecting rod-crank structure, increasing bearing friction.

[0028] Combination Figures 1 to 2 As shown, according to a specific embodiment of this application, a double crankshaft internal combustion engine is provided.

[0029] Specifically, the dual-crankshaft internal combustion engine includes: a first cylinder assembly 1; and a second cylinder assembly 2, the first cylinder assembly 1 and the second cylinder assembly 2 being arranged in a mirror image; the first cylinder assembly 1 includes: a first piston assembly 11, the first piston assembly 11 being installed within a first cylinder liner 101, and the first piston assembly 11 reciprocating within the first cylinder liner 101; and a first reciprocating connecting rod coupler 106, the first reciprocating connecting rod coupler 106 being installed within a first cylinder block guide 105, one end of the first reciprocating connecting rod coupler 106 being hinged to the first piston assembly 11, and the other end of the first reciprocating connecting rod coupler 106 being connected to a first crank structure 10; the second... The cylinder assembly 2 includes: a second piston assembly 21, which is installed inside the second cylinder liner 201 and reciprocates within the second cylinder liner 201; and a second reciprocating connecting rod coupler 206, which is installed inside the second cylinder guide 205, with two ends hinged to the second piston assembly 21 and the other end connected to the second crank structure 20; wherein the first piston assembly 11 and the second piston assembly 21 operate synchronously, and the first crank structure 10 and the second crank structure 20 are arranged in opposite directions of motion.

[0030] The first cylinder assembly 1 and the second cylinder assembly 2 are not only symmetrically distributed in space, but also mirror images of each other in terms of the geometry and relative position of their internal components. This arrangement enables the two cylinders to produce mechanical behaviors with symmetrical motion trajectories and opposite force directions, providing a structural prerequisite for the mutual cancellation of subsequent lateral thrust.

[0031] The first piston assembly 11 is installed inside the first cylinder liner 101 and performs linear reciprocating motion therein. The first cylinder liner 101, as a fixed component, provides guidance and support for the first piston assembly 11, ensuring the linearity of its motion trajectory.

[0032] The first reciprocating connecting rod coupler 106 is installed within the first cylinder guide 105, which is also a fixed component used to constrain the kinematic freedom of the first reciprocating connecting rod coupler 106. One end of the first reciprocating connecting rod coupler 106 is hinged to the first piston assembly 11, receiving the reciprocating load from the piston; the other end is connected to the first crank structure 10, converting the reciprocating motion into rotational motion. Crucially, the sliding fit of the first reciprocating connecting rod coupler within the cylinder guide allows it to withstand and transmit the lateral force applied by the connecting rod, while simultaneously balancing these lateral forces through a mirror-symmetric structure in coordination with other components.

[0033] The second piston assembly 21 is installed inside the second cylinder liner 201 and performs reciprocating motion synchronously with the first piston assembly 11.

[0034] The second reciprocating connecting rod coupler 206 is installed inside the second cylinder guide 205, with one end hinged to the second piston assembly 21 and the other end connected to the second crank structure 20. Its function is mirror-symmetrical to that of the first reciprocating connecting rod coupler, together forming the critical path for lateral thrust transmission and balance.

[0035] The first and second piston assemblies operate synchronously. This means that the displacement, velocity, and acceleration of the two pistons at any given moment are identical in a mirror coordinate system. This synchronicity ensures that the inertial forces and gas forces generated by the two cylinders are symmetrical in a specific direction.

[0036] The first and second crank structures are arranged in opposite directions of motion. Combined with the mirror-arranged cylinder assemblies, this reverse motion means that when the first crank rotates clockwise, the second crank rotates counterclockwise (or vice versa, depending on the specific phase definition, but the core is that the directions are opposite). This reverse rotation, combined with the mirror-arranged piston motion, results in the lateral forces (i.e., the piston's thrust on the cylinder liner) generated by the two cylinders during power output also being in opposite directions.

[0037] Because the first and second cylinder assemblies are arranged in a mirror image and the pistons move synchronously, the lateral thrust generated by the two pistons during their reciprocating motion is equal in magnitude and opposite in direction. Simultaneously, the counter-rotating crankshaft further ensures torque balance during power transmission. This mechanical symmetry causes the lateral thrusts on both sides to cancel each other out, thereby significantly reducing or even eliminating the lateral contact force between the piston and cylinder liner. This significant reduction in lateral thrust between the piston and cylinder liner directly reduces the sliding friction work between them. Reduced friction loss means that more combustion energy is converted into effective mechanical work, rather than being consumed in overcoming friction. By reducing friction work, the mechanical efficiency of the internal combustion engine is improved, thereby increasing the engine's effective thermal efficiency.

[0038] By applying the technical solution of this invention, the effective cancellation of piston lateral thrust is achieved through the mirror-symmetrical arrangement and synchronous operation of the first cylinder assembly 1 and the second cylinder assembly 2. The first piston assembly 11 and the second piston assembly 21 reciprocate within their respective cylinder liners. The motion of the piston assemblies is transmitted to the first crank structure 10 and the second crank structure 20 respectively via the first reciprocating connecting rod coupler 106 and the second reciprocating connecting rod coupler 206. The first crank structure 10 and the second crank structure 20 are arranged in opposite directions of motion. This mirror-symmetrical and reverse transmission mechanism balances the lateral forces generated by the two cylinders during operation, thereby significantly reducing the sliding friction loss between the piston and the cylinder liner and improving the effective thermal efficiency of the internal combustion engine.

[0039] Furthermore, the second reciprocating link coupling body 206 and the first reciprocating link coupling body 106 are interlocked, and a sliding pair is formed between the second reciprocating link coupling body 206 and the first reciprocating link coupling body 106.

[0040] The first reciprocating link coupler 106 and the second reciprocating link coupler 206 are not simply arranged side-by-side or separately, but rather employ a "mutually interlocking" mechanical structure design. This means that the contact interfaces of the two couplers have complementary geometries, such as concave-convex fits, dovetail groove fits, or cylindrical surface fits, etc. The specific form is subject to actual implementation, but the core is "interlocking," which allows a part of one coupler to be inserted into or wrapped in the corresponding structure of the other coupler. This interlocking structure achieves physical connection and constraint of two independent moving components in space, ensuring the relative positional stability of the two during motion and preventing accidental separation or misalignment of the two in the direction perpendicular to the motion direction.

[0041] Based on their interlocking, a "sliding pair" is formed between the contact surfaces of the first reciprocating connecting rod coupler 106 and the second reciprocating connecting rod coupler 206. A sliding pair is a kinematic pair that allows relative sliding between two components. In this design, this sliding pair allows the first reciprocating connecting rod coupler 106 and the second reciprocating connecting rod coupler 206 to slide slightly relative to each other along a specific direction—usually parallel to or perpendicular to the piston axis to absorb lateral forces—depending on the specific interlocking surfaces. This sliding is not arbitrary but guided and constrained by the interlocking structure, ensuring that the sliding occurs along a predetermined trajectory. Simultaneously, contact pressure exists between the sliding pair interfaces, enabling the transmission of normal and tangential frictional forces between the two couplers.

[0042] The first and second cylinder assemblies are arranged in a mirror image, with the pistons moving synchronously but experiencing opposite forces. The first reciprocating connecting rod coupler 106 bears the lateral force from the first connecting rod, and the second reciprocating connecting rod coupler 206 bears the lateral force from the second connecting rod. Since the two couplers interlock to form a sliding pair, the lateral force generated on the first side is directly transmitted to the second side through the interlocking interface, and vice versa. The sliding pair allows for fine-tuning of this force transmission through relative sliding, thereby ensuring that the equal and opposite lateral thrusts generated by the two cylinders cancel each other out at the contact surface of the couplers. This fundamentally eliminates the lateral load between the piston and cylinder liner, allowing the piston to primarily bear the axial gas pressure and significantly reducing lateral friction between the piston and cylinder liner.

[0043] In practical engineering, precise mirror-symmetric structures place extremely high demands on manufacturing tolerances and assembly accuracy. If the two coupled bodies are rigidly fixed, such as by welding or interference fit, any minute dimensional deviation, thermal deformation, or assembly error can cause the mechanism to jam, i.e., an "over-constraint" problem. Introducing a "sliding pair" design grants a certain degree of freedom, i.e., a slight sliding capability, between the first reciprocating connecting rod coupling body 106 and the second reciprocating connecting rod coupling body 206. When there are slight differences in the working conditions of the two cylinders, such as combustion pressure fluctuations, deformation caused by uneven temperature distribution, or machining errors in components, the sliding pair allows for a small relative displacement between the coupled bodies to absorb these differences. This "flexible" connection ensures smooth movement of the mechanism under complex working conditions, avoids jamming, abnormal wear, or structural damage caused by rigid constraints, and improves the reliability and fault tolerance of the mechanism.

[0044] Furthermore, the first piston assembly 11 includes: a first piston body 102, which reciprocates within the first cylinder liner 101; and a first reciprocating connecting rod 104, one end of which is hinged to the first piston body 102 via a first piston pin 103, and the other end of which is connected to a first reciprocating connecting rod coupling body 106.

[0045] The first piston body 102 is the core component that bears the combustion gas pressure and realizes energy conversion. It is housed inside the first cylinder liner 101 and performs strictly linear reciprocating motion within it. The outer circumferential surface of the first piston body 102 forms a sliding fit with the inner wall of the first cylinder liner 101. This fit ensures the guiding accuracy and sealing of the piston movement. Although the sealing ring is not described in detail in this paragraph, it is a fundamental implicit condition for the reciprocating motion of the piston within the cylinder liner. The main function of the first piston body 102 is to transmit the axial thrust generated by the high-temperature and high-pressure gas in the combustion chamber to the moving mechanism.

[0046] The first reciprocating connecting rod 104 constitutes a key intermediate link in the motion transmission of the first cylinder assembly. One end of it is hinged to the first piston body 102 via the first piston pin 103. This hinged connection allows the first reciprocating connecting rod 104 to swing relative to the first piston body 102 within a certain angle range, thereby adapting to the angle changes of the connecting rod caused by the rotation of the crank during movement. The other end of the first reciprocating connecting rod 104 is connected to the first reciprocating connecting rod coupling body 106. This connection ensures that the axial force generated by the piston and the lateral component force generated by the swinging of the connecting rod can be effectively transmitted to the first reciprocating connecting rod coupling body 106. It is worth noting that the term "first reciprocating connecting rod" is explicitly used here as an independent component. It is different from the traditional "connecting rod." Its design purpose may be to facilitate the subsequent connection with the "coupling body," or its structural form, such as length and cross-section, may be specially designed to optimize force or spatial layout.

[0047] The first piston pin 103, serving as the pivot connecting the first piston body 102 and the first reciprocating connecting rod 104, plays a crucial pivotal role. It not only bears enormous alternating loads but also ensures the flexibility and reliability of the articulated motion between the two. Through the piston pin, the planar motion of the connecting rod is transformed into the reciprocating linear motion of the piston, achieving a change in motion mode.

[0048] During the reciprocating motion of the first piston, the piston exerts a lateral thrust on the cylinder liner due to the connecting rod angle. One end of the first reciprocating connecting rod 104 is hinged to the piston, and the other end is connected to the coupling body. It not only transmits axial force, but its oscillating characteristics also mean that it is subject to a lateral component force. However, since the first reciprocating connecting rod coupling body 106 is installed within the fixed first cylinder guide 105 and forms a sliding pair with the coupling body on the mirror side, the lateral component force transmitted from the first reciprocating connecting rod 104 is guided to the first reciprocating connecting rod coupling body 106 and ultimately canceled out by the interaction between the coupling bodies. This design allows the piston itself to no longer directly bear the huge lateral reaction force, but instead transmits the force to the specially designed guide and coupling structure through the connecting rod mechanism.

[0049] Because the first reciprocating connecting rod 104 transmits the piston's motion and force to the first reciprocating connecting rod coupling 106, and the first reciprocating connecting rod coupling 106 and its mirror-side second reciprocating connecting rod coupling 206 interlock to form a sliding pair, this structure allows the lateral force generated by the piston to be balanced and canceled at the coupling level. Therefore, when the first piston body 102 moves within the first cylinder liner 101, the lateral thrust it experiences is greatly reduced, ideally approaching zero. The elimination of lateral thrust directly leads to a significant reduction in the sliding friction work between the piston and the cylinder liner, thereby reducing wear and improving the engine's mechanical efficiency and service life.

[0050] Further, the first crank structure 10 includes: a first connecting rod 108, one end of which is hinged to a first reciprocating connecting rod coupling body 106 via a first connecting rod pin 107; a first crank 110, one end of which is hinged to the other end of the first connecting rod 108 via a first crank pin 109, and the other end of the first crank 110 is connected to a first synchronous gear 111; wherein, the ratio of the length L1 of the first connecting rod 108 to the crank radius R1 of the first crank 110 satisfies: 3.0≤L1 / R1≤4.5.

[0051] The first connecting rod 108 is a key transmission component connecting the first reciprocating connecting rod coupler 106 and the first crank 110. One end of the first connecting rod 108 is hinged to the first reciprocating connecting rod coupler 106 via the first connecting rod pin 107. This hinge allows the first connecting rod 108 to swing relative to the coupler, thereby adapting to angle changes during motion. The other end of the first connecting rod 108 is hinged to the first crank 110 via the first crank pin 109. Through this two-end hinged structure, the first connecting rod 108 converts the rotational motion from the first crank 110 into the reciprocating or swinging motion tendency of the first reciprocating connecting rod coupler 106. It bears and transmits the huge alternating loads generated during the engine's working cycle, including tension and compression.

[0052] The first crank 110, as the core rotating component for power output, has one end hinged to the first connecting rod 108 via a first crank pin 109, and the other end connected to a first synchronizing gear 111. This connection structure indicates that the rotation of the first crank 110 is not only used for power output, but also establishes a motion synchronization relationship with the second crank or related transmission mechanism on the other side through the first synchronizing gear 111. The first synchronizing gear 111 ensures phase synchronization and rotation direction control between the first crank and the mirror-side crankshaft, and is the key mechanical link for realizing the core working logic of "mirror synchronization and reverse rotation".

[0053] The scheme explicitly defines the range of the ratio of the length L1 of the first connecting rod 108 to the crank radius R1 of the first crank 110: 3.0 ≤ L1 / R1 ≤ 4.5. This geometric parameter is a key indicator determining the motion characteristics of the crank-connecting rod mechanism. Within this range, the connecting rod is relatively long relative to the crank radius, meaning that during crankshaft rotation, the angle between the connecting rod and the cylinder centerline or the piston's direction of motion changes more gradually, and the swing angle is smaller. This scheme effectively reduces the connecting rod swing angle by increasing the length-to-diameter ratio, thereby significantly reducing the lateral force acting on the piston from the source. Combined with the side thrust cancellation characteristic of the mirror structure in this application, the contact force between the piston and the cylinder liner is extremely small, greatly improving efficiency.

[0054] A larger length-to-diameter ratio allows the connecting rod to be subjected to forces closer to the axial direction during operation, reducing bending stress within the connecting rod and lateral loads at the piston pin. This not only reduces wear on the connecting rod, piston pin, and bearings but also improves the mechanical efficiency and reliability of the mechanism. Simultaneously, smaller lateral forces mean less lateral clamping force on the piston rings, contributing to improved sealing and reduced oil pumping. The longer connecting rod allows for smoother acceleration changes in the piston as it approaches top and bottom dead centers, reducing the impact of inertial forces. This helps reduce engine vibration and noise, improving overall performance.

[0055] Furthermore, the second piston assembly 21 includes: a second piston body 202, which reciprocates within the second cylinder liner 201; and a second reciprocating connecting rod 204, one end of which is hinged to the second piston body 202 via a second piston pin 203, and the other end of which is connected to a second reciprocating connecting rod coupling body 206.

[0056] Furthermore, the first piston body 102 and the second piston body 202 move synchronously and in the same direction.

[0057] The second piston body 202 is the core moving component in the second cylinder assembly that directly bears the combustion pressure. It is installed inside the second cylinder liner 201 and performs linear reciprocating motion within it. The outer circumferential surface of the second piston body 202 forms a sliding fit with the inner wall of the second cylinder liner 201. This fit ensures that the piston can maintain the correct movement trajectory under the action of high-pressure combustion gas, prevents gas leakage, and effectively transmits the axial thrust generated by combustion to the moving mechanism.

[0058] The second reciprocating connecting rod 204 constitutes a key transmission rod in the second cylinder assembly, connecting the piston and the coupling body. One end of it is hinged to the second piston body 202 via the second piston pin 203. This hinged design allows the second reciprocating connecting rod 204 to swing relative to the piston in the plane of motion to accommodate changes in the connecting rod angle as the crankshaft rotates. The other end of the second reciprocating connecting rod 204 is connected to the second reciprocating connecting rod coupling body 206. Through this connection, the axial force of the combustion gas on the second piston body 202 and the lateral force generated by the swinging of the connecting rod are transmitted to the second reciprocating connecting rod coupling body 206.

[0059] The second piston pin 203, as a shaft-like component connecting the second piston body 202 and the second reciprocating connecting rod 204, plays a crucial hinge role. It not only bears the alternating load from the piston but also ensures the flexibility and reliability of the relative movement between the piston and the connecting rod, achieving effective conversion of motion modes.

[0060] The second piston assembly, comprising a second piston body 202, a second reciprocating connecting rod 204, and a second piston pin 203, has a structure that is a complete mirror image of the first piston assembly, comprising a first piston body 102, a first reciprocating connecting rod 104, and a first piston pin 103. This symmetrical structural layout is the basis for the "mirror image symmetry" working principle of this invention, ensuring consistency in the geometric dimensions, mass distribution, and kinematic characteristics of the two cylinders, thus providing the prerequisite for subsequent force balance.

[0061] During the reciprocating motion of the second piston, due to the connecting rod angle, the piston generates a lateral thrust on the second cylinder liner. The second reciprocating connecting rod 204 transmits this lateral force from the piston to the second reciprocating connecting rod coupling 206. Since the second reciprocating connecting rod coupling 206 is installed within the fixed second cylinder guide 205 and interlocks with the first reciprocating connecting rod coupling 106 to form a sliding pair, the lateral force generated on the second side is guided to the coupling interface. Through this structure, the piston itself no longer directly bears the huge lateral reaction force, but instead transfers the lateral load to a specially designed guiding and coupling balance structure, achieving decoupling of the piston's lateral load.

[0062] Combined with the mirror-coupled sliding pair mechanism described above, the lateral force generated by the second piston assembly is canceled out by the interaction between the second reciprocating connecting rod coupler 206 and the first reciprocating connecting rod coupler 106. This means that the net lateral thrust experienced by the second piston body 202 when moving within the second cylinder liner 201 is extremely small. The elimination of lateral thrust directly leads to a significant reduction in the sliding friction work between the piston rings and the cylinder liner, and between the piston skirt and the cylinder liner, thereby reducing mechanical wear and improving the engine's mechanical efficiency and effective thermal efficiency.

[0063] The precise coordination of all components in the second piston assembly ensures that the second piston can reciprocate synchronously with the first piston. This synchronicity is crucial for the normal operation of a mirror-piston double-crankshaft internal combustion engine. Only with synchronous motion can the centrifugal force and inertial force generated by the counter-rotating cranks on both sides be balanced, and the lateral forces generated by the pistons on both sides be canceled out, thereby achieving smooth engine operation and low vibration characteristics.

[0064] Further, the second crank structure 20 includes: a second connecting rod 208, one end of which is hinged to a second reciprocating connecting rod coupling body 206 via a second connecting rod pin 207; a second crank 210, one end of which is hinged to the other end of the second connecting rod 208 via a second crank pin 209, and the other end of which is connected to a second synchronous gear 211; wherein, the ratio of the length L2 of the second connecting rod 208 to the crank radius R2 of the second crank 210 satisfies: 3.0≤L2 / R2≤4.5.

[0065] The second connecting rod 208, as a key transmission component connecting the coupling body and the crankshaft in the second cylinder assembly, has one end hinged to the second reciprocating connecting rod coupling body 206 via the second connecting rod pin 207. This hinged design allows the second connecting rod 208 to swing freely relative to the coupling body in the plane of motion to adapt to the angle changes required during movement. The other end of the second connecting rod 208 is hinged to the second crank 210 via the second crank pin 209. Through this two-end hinged structure, the second connecting rod 208 converts the rotational motion from the second crank 210 into the reciprocating or oscillating motion tendency of the second reciprocating connecting rod coupling body 206, and withstands the alternating tensile and compressive loads generated during the engine's working cycle.

[0066] The second crank 210 is the core rotating component for power output of the second cylinder assembly. One end of it is hinged to the second connecting rod 208 via the second crank pin 209, and the other end of the second crank 210 is connected to the second synchronizing gear 211. This connection structure indicates that the second crank 210 is not only responsible for outputting power, but also establishes a mechanical synchronization connection with the first synchronizing gear 111 through the second synchronizing gear 211. This synchronous connection ensures that the rotational phase and speed between the second crank 210 and the first crank 110 remain strictly synchronized. It is the key mechanical link for realizing the core working logic of "mirror synchronization and reverse rotation," ensuring that the relative positions of the two cranks at any given time meet the requirement of mirror symmetry.

[0067] Specifically, in this embodiment, the ratio of the length L2 of the second connecting rod 208 to the crank radius R2 of the second crank 210 is the same as the ratio of the length L1 of the first connecting rod 108 to the crank radius R1 of the first crank 110, to ensure that the first piston assembly and the second piston assembly work synchronously.

[0068] Furthermore, the second reciprocating connecting rod coupler 206 is provided with a second sliding pair surface 2061, and the first reciprocating connecting rod coupler 106 is provided with a first sliding pair surface 1061. The first sliding pair surface 1061 and the second sliding pair surface 2061 are fitted together to form a sliding pair. The sliding pair is used to allow a small relative sliding displacement between the second reciprocating connecting rod coupler 206 and the first reciprocating connecting rod coupler 106 to accommodate machining errors or deformation differences.

[0069] The surface of the first reciprocating link coupler 106 is provided with a first sliding joint surface 1061, and the surface of the second reciprocating link coupler 206 is provided with a second sliding joint surface 2061. These two surfaces are geometrically complementary or matched; for example, one is a convex surface and the other a concave surface, or both are contact surfaces with specific curvatures to ensure good surface or line contact characteristics during contact. This surface design aims to provide stable guidance and support while allowing specific relative motion.

[0070] The first sliding pair surface 1061 and the second sliding pair surface 2061 are fitted together, forming a "sliding pair". This fit is not a rigid weld or interference fit, but rather maintains contact while allowing relative displacement. The sliding pair is defined as constraining the separation of the two coupled bodies in the normal direction, but allowing them to slide relative to each other in the tangential direction, i.e., along the direction of the surface extension or a specific sliding trajectory. This structure ensures that the two coupled bodies can accommodate small positional deviations while transmitting force.

[0071] The core function of this sliding pair is explicitly described as "allowing minute relative sliding displacements," with the aim of "accommodating machining errors or deformation differences." This means that during manufacturing, due to limitations in material properties and processing techniques, dimensional and geometric tolerances are unavoidable between the first and second coupling bodies and their related components such as the cylinder block and connecting rods. Furthermore, during engine operation, components undergo minute elastic or plastic deformations due to factors such as thermal expansion and uneven load distribution. The minute degrees of freedom provided by the sliding pair allow these errors or deformations to "accommodate" deviations in the theoretically ideal positions of the two coupling bodies through minute relative sliding, rather than generating significant internal stress. The sliding pair provides the necessary kinematic flexibility while transmitting lateral balancing forces. It ensures that the first and second reciprocating connecting rod coupling bodies can effectively support each other and counteract lateral thrust.

[0072] Furthermore, such as Figure 2 As shown, the second sliding joint surface 2061 is located between the first sliding joint surfaces 1061 on both sides, and the second sliding joint surface 2061 protrudes from the first sliding joint surface 1061.

[0073] Specifically, the first reciprocating linkage coupling body 106 has two opposing first sliding joint surfaces 1061 in the contact area. These two first sliding joint surfaces 1061 are arranged parallel or symmetrically to form a receiving space. The second reciprocating linkage coupling body 206 is located inside this space, with its second sliding joint surface 2061 protruding and embedded in the channel or groove formed by the first sliding joint surfaces 1061. This structure mechanically forms a "clamping" or "enveloping" shape, that is, the first coupling body encloses the contact surface of the second coupling body from both sides. "Protruding" means that the second sliding joint surface 2061 has a larger radius of curvature or a specific protrusion shape, such as a cylindrical surface, a spherical surface, or a protrusion with a specific contour, relative to the first sliding joint surface 1061, so that the two form a stable surface contact or line contact when in contact. This protruding design ensures that the second sliding joint surface 2061 can fit tightly between the first sliding joint surfaces 1061 on both sides, providing sufficient contact area to transmit load, while restricting the degree of freedom of the second coupling body in the direction perpendicular to the sliding direction.

[0074] The second sliding pair surface 2061 and the first sliding pair surfaces 1061 on both sides form two independent sliding contact interfaces. These two interfaces together constitute a complete sliding pair system. The first sliding pair surface 1061 serves as the outer guide wall, and the second sliding pair surface 2061 serves as the inner guided component. The two work together to achieve guidance and constraint of relative motion.

[0075] According to another aspect of the present invention, a vehicle is provided having a double-crankshaft internal combustion engine, wherein the double-crankshaft internal combustion engine is the aforementioned double-crankshaft internal combustion engine.

[0076] The technical solution of this embodiment has the following technical effects: The twin-crankshaft internal combustion engine of this application achieves effective cancellation of piston side thrust through the mirror-symmetrical arrangement and synchronous operation of the first cylinder assembly and the second cylinder assembly. The second reciprocating connecting rod coupler 206 and the first reciprocating connecting rod coupler 106 are interlocked and form a sliding pair between them, which cancels the side thrust between the piston and the cylinder liner, greatly reduces the friction loss between the piston and the cylinder liner, and improves the effective thermal efficiency of the engine. Each piston is equipped with a crank structure, and the crank friction work accounts for a smaller proportion, resulting in a higher effective thermal efficiency compared to the single-piston twin-crank structure.

[0077] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0078] In addition to the above, it should be noted that the terms "one embodiment," "another embodiment," and "embodiment" used in this specification refer to specific features, structures, or characteristics described in connection with that embodiment, which are included in at least one embodiment described in the general description of this application. The appearance of the same expression in multiple places in the specification does not necessarily refer to the same embodiment. Furthermore, when a specific feature, structure, or characteristic is described in connection with any embodiment, the intention is to suggest that implementing such a feature, structure, or characteristic in conjunction with other embodiments also falls within the scope of this invention.

[0079] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0080] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A double-crankshaft internal combustion engine, characterized by, include: First cylinder assembly (1); The second cylinder assembly (2) is arranged in a mirror image of the first cylinder assembly (1) and the second cylinder assembly (2); The first cylinder assembly (1) includes: a first piston assembly (11), the first piston assembly (11) is installed in a first cylinder liner (101), and the first piston assembly (11) reciprocates within the first cylinder liner (101); The first reciprocating connecting rod coupler (106) is installed in the first cylinder guide (105). One end of the first reciprocating connecting rod coupler (106) is hinged to the first piston assembly (11), and the other end of the first reciprocating connecting rod coupler (106) is connected to the first crank structure (10). The second cylinder assembly (2) includes: a second piston assembly (21), which is installed in a second cylinder liner (201) and reciprocates within the second cylinder liner (201); The second reciprocating connecting rod coupler (206) is installed in the second cylinder guide (205). One end of the second reciprocating connecting rod coupler (206) is hinged to the second piston assembly (21), and the other end of the second reciprocating connecting rod coupler (206) is connected to the second crank structure (20). The first piston assembly (11) and the second piston assembly (21) work synchronously, and the first crank structure (10) and the second crank structure (20) are arranged in opposite directions of motion.

2. The double curved shaft internal combustion engine of claim 1, wherein, The second reciprocating link coupling body (206) and the first reciprocating link coupling body (106) are fitted together, and a sliding pair is formed between the second reciprocating link coupling body (206) and the first reciprocating link coupling body (106).

3. The double-crankshaft internal combustion engine according to claim 2, characterized in that, The first piston assembly (11) includes: The first piston body (102) reciprocates within the first cylinder liner (101); The first reciprocating connecting rod (104) has one end hinged to the first piston body (102) via the first piston pin (103), and the other end of the first reciprocating connecting rod (104) is connected to the first reciprocating connecting rod coupling body (106).

4. The double-crankshaft internal combustion engine according to claim 3, characterized in that, The first crank structure (10) includes: The first link (108) has one end hinged to the first reciprocating link coupling body (106) via the first link pin (107); The first crank (110) has one end hinged to the other end of the first connecting rod (108) via a first crank pin (109), and the other end of the first crank (110) is connected to the first synchronous gear (111). The ratio of the length L1 of the first connecting rod (108) to the crank radius R1 of the first crank (110) satisfies: 3.0≤L1 / R1≤4.

5.

5. The double-crankshaft internal combustion engine according to claim 3, characterized in that, The second piston assembly (21) includes: The second piston body (202) reciprocates within the second cylinder liner (201); The second reciprocating connecting rod (204) has one end hinged to the second piston body (202) via the second piston pin (203), and the other end of the second reciprocating connecting rod (204) is connected to the second reciprocating connecting rod coupling body (206).

6. The double-crankshaft internal combustion engine according to claim 5, characterized in that, The first piston body (102) moves synchronously with the second piston body (202) and moves in the same direction.

7. The double-crankshaft internal combustion engine according to claim 4, characterized in that, The second crank structure (20) includes: The second link (208) has one end hinged to the second reciprocating link coupling body (206) via the second link pin (207); The second crank (210) has one end hinged to the other end of the second connecting rod (208) via a second crank pin (209), and the other end of the second crank (210) is connected to the second synchronous gear (211); The ratio of the length L2 of the second connecting rod (208) to the crank radius R2 of the second crank (210) satisfies: 3.0≤L2 / R2≤4.

5.

8. The double-crankshaft internal combustion engine according to claim 2, characterized in that, The second reciprocating connecting rod coupling body (206) is provided with a second sliding pair surface (2061), and the first reciprocating connecting rod coupling body (106) is provided with a first sliding pair surface (1061). The first sliding pair surface (1061) and the second sliding pair surface (2061) are fitted together to form the sliding pair. The sliding pair is used to allow a small relative sliding displacement between the second reciprocating connecting rod coupling body (206) and the first reciprocating connecting rod coupling body (106) to adapt to machining errors or deformation differences.

9. The double-crankshaft internal combustion engine according to claim 8, characterized in that, The second sliding joint surface (2061) is located between the first sliding joint surfaces (1061) on both sides, and the second sliding joint surface (2061) protrudes from the first sliding joint surface (1061).

10. A vehicle, characterized in that, The vehicle has a double-crankshaft internal combustion engine, which is the double-crankshaft internal combustion engine according to any one of claims 1-9.

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