Crank-link mechanism and engine

Abstract

The invention provides a crank connecting rod mechanism and an engine, and relates to the field of engine gas saving, and the crank connecting rod mechanism comprises a crankshaft, a crank and a connecting rod. The small end of the connecting rod is connected with the piston, the large end of the connecting rod is connected with the first end of the crank, the crank rotates around the center of the crankshaft, a protruding piece is arranged on the edge of the second end of the crank, and the first movement track of the protruding piece intersects with the second movement track of the reed valve. The first movement track of the protruding piece is the movement track of the protruding piece when the crank rotates around the center of the crankshaft from the first position to the second position, and the second movement track is the movement track of the protruding piece when the crank rotates around the center of the crankshaft from the first position to the second position. The second motion trail refers to the motion trail of the reed valve rebounded from the maximum opening position to the closing position. In this way, springback of the reed valve can be accelerated, and it is prevented that combustible mixed gas which enters the crankcase and is supplied to the engine flows back through the reed valve, leakage of the combustible mixed gas supplied to the engine is caused, and the performance of the engine is affected.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of engine throttling, and specifically to a crank-connecting rod mechanism and an engine. Background Art

[0002] During the operation of a two-stroke engine, the combustible mixture in the intake duct first enters the crankcase through the reed valve and then enters the combustion chamber. The speed at which the reed valve opens and closes has a significant impact on the intake efficiency of the combustible mixture. The reed valve is usually designed to be softer to reduce the resistance when the reed valve opens and improve the intake efficiency, but this also results in a slower rebound speed of the reed valve. The slow rebound speed of the reed valve will cause the combustible mixture that has entered the crankcase to flow back through the reed valve, causing leakage of the combustible mixture, affecting the performance of the engine.

[0003] In current engines, a limit plate is usually installed on the reed valve seat to control the opening and closing range of the reed valve, allowing the reed valve to rebound according to certain dynamic rules to avoid the reed valve rebounding slowly due to excessive opening. However, under high flow conditions, the presence of the limit plate will cause the reed valve to rebound prematurely. At this time, the intake has not yet been completed. Under the impact of the intake air flow, the reed valve will open again, causing the reed valve to open and close repeatedly, which not only causes great intake resistance, but also damages the reed valve. In addition, the limit plate also limits the opening degree of the reed valve. Under conditions that require a large flow, it is impossible to provide sufficient combustible mixture to the combustion chamber, resulting in a low upper limit of engine power.

[0004] Therefore, how to accelerate the rebound of the reed valve to prevent leakage of the combustible mixture supplied to the engine is a key issue that needs to be solved at present. Summary of the invention

[0005] In view of the above problems, an embodiment of the present application provides a crank-connecting rod mechanism and an engine, which overcomes or at least partially solves the above problem of how to accelerate the rebound of the reed valve to prevent leakage of the combustible mixture supplied to the engine.

[0006] In the first aspect of the embodiments of the present application, a crank-connecting rod mechanism is provided, which is arranged in a crankcase, and the mechanism includes: a crankshaft, a crank and a connecting rod. The small end of the connecting rod is connected to the piston, and the large end of the connecting rod is connected to the first end of the crank. The crank rotates around the center of the crankshaft, and the center of the crankshaft is the rotation center of the crankshaft. A protrusion is provided at the edge of the second end of the crank, and the first motion trajectory of the protrusion and the second motion trajectory of the reed valve intersect, so that when the crank rotates around the center of the crankshaft, the protrusion pushes the reed valve to rebound to the closed position. Among them, the first motion trajectory of the protrusion refers to the motion trajectory of the protrusion when the crank rotates around the center of the crankshaft from the first position to the second position, and the second motion trajectory refers to the motion trajectory of the reed valve rebounding from the maximum open position to the closed position.

[0007] In this embodiment, since the crank rotates around the center of the crankshaft, a protrusion is provided at the edge of the second end of the crank, and the first movement trajectory of the protrusion intersects with the second movement trajectory of the reed valve. In this way, during the normal rotation of the crank, the protrusion can push the reed valve to rebound to the closed position. In this way, the rebound of the reed valve can be accelerated, thereby preventing the combustible mixture gas supplied to the engine that has entered the crankcase from flowing back through the reed valve, causing the combustible mixture gas supplied to the engine to leak, thereby affecting the performance of the engine.

[0008] In an optional manner, the initial intersection point of the first motion trajectory of the protrusion and the second motion trajectory of the reed valve is located between the starting end of the reed valve and the midpoint of the reed valve.

[0009] In this way, the protrusion can contact the reed valve earlier as the crank rotates around the center of the crankshaft, thereby increasing the duration of the protrusion pushing the reed valve to rebound, so as to make the reed valve rebound faster.

[0010] In an optional manner, the surface of the protruding member that contacts the reed valve is a smooth surface.

[0011] In this way, the damage to the reed valve when the protrusion pushes the reed valve to rebound can be reduced.

[0012] In an optional manner, the protruding member is a square.

[0013] In an optional manner, the top angle of the second end of the block away from the crank is an arc chamfer.

[0014] In this way, when the block just contacts the reed valve and pushes the reed valve to rebound, the top corner of the block will not scratch the reed valve.

[0015] In an optional manner, when the protrusion pushes the reed valve to rebound to the closed position, rolling friction occurs between the protrusion and the reed valve.

[0016] In an optional embodiment, the protrusion includes a first shaft and a first bearing, the first shaft and the first bearing cooperate with each other, a first accommodating hole is provided at the second end of the crank, a second accommodating hole is provided on the first bearing, the first shaft passes through the second accommodating hole and is fixed to the first accommodating hole, so that the protrusion is fixed to the second end of the crank.

[0017] In this way, rolling friction is formed between the protrusion and the reed valve, so that the protrusion causes less damage to the reed valve.

[0018] In an optional embodiment, the protrusion includes a second shaft and a second bearing, the second shaft and the second bearing cooperate with each other, the second bearing is provided with a third accommodating hole, the second shaft passes through the third accommodating hole and is fixed to the surface of the second end of the crank, so that the protrusion is fixed to the second end of the crank.

[0019] The second aspect of the embodiment of the present application provides an engine, comprising: a crankcase, a scavenging passage, a piston, a combustion chamber, an exhaust passage, and the crank-connecting rod mechanism provided in the first aspect of the embodiment of the present application. The crank-connecting rod mechanism is arranged in the crankcase, the crankcase is connected to the combustion chamber through the scavenging passage, the combustion chamber is also connected to the exhaust passage, and the combustion chamber is located on the side of the piston away from the connecting rod.

[0020] In this embodiment, the protrusion in the crank-connecting rod mechanism can push the reed valve to rebound from the maximum open position to the closed position. In this way, the rebound of the reed valve can be accelerated, thereby preventing the combustible mixture supplied to the engine that has entered the crankcase from flowing back through the reed valve, causing the combustible mixture supplied to the engine to leak and affecting the performance of the engine.

[0021] The above description is only an overview of the technical solution of the embodiment of the present application. In order to more clearly understand the technical means of the embodiment of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the embodiment of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0023] Figure 1 A schematic structural diagram of a crank-connecting rod mechanism provided in some embodiments of the present application.

[0024] Figure 2 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in a first position.

[0025] Figure 3 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the second position.

[0026] Figure 4 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the third position.

[0027] Figure 5 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the fourth position.

[0028] Figure 6 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the fifth position.

[0029] Figure 7 A schematic diagram of another crank-connecting rod mechanism provided for some embodiments of the present application.

[0030] Figure 8 A schematic diagram of yet another crank-connecting rod mechanism provided for some embodiments of the present application.

[0031] Fig. 9 A schematic diagram of yet another crank-connecting rod mechanism provided for some embodiments of the present application. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by technicians in the technical field to which this application belongs; the terms used in the specification of the application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0034] The terms "comprising" and "having" and any variations thereof in the specification, claims and drawings of this application are intended to cover but not exclude other contents. The word "a" or "an" does not exclude the presence of a plurality.

[0035] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase "embodiments" in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0036] In addition, the terms "first", "second", etc. in the specification and claims of this application or the above-mentioned drawings are used to distinguish different objects rather than to describe a specific order, and may explicitly or implicitly include one or more of the features.

[0037] In the description of the present application, unless otherwise specified, "plurality" means more than two (including two), and similarly, "multiple groups" means more than two groups (including two).

[0038] In the description of the present application, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense. For example, the "connection" or "connection" of a mechanical structure may refer to a physical connection. For example, the physical connection may be a fixed connection, such as a fixed connection through a fixing member, such as a fixed connection through a screw, bolt or other fixing member; the physical connection may also be a detachable connection, such as a mutual snap connection or snap connection; the physical connection may also be an integral connection, such as welding, bonding or integral molding to form a connection for connection. The "connection" or "connection" of a circuit structure may refer to an electrical connection or a signal connection in addition to a physical connection. For example, it may be a direct connection, that is, a physical connection, or it may be an indirect connection through at least one intermediate element, as long as the circuit is connected, or it may be the internal connection of two elements; the signal connection may refer to a signal connection through a media medium, such as a radio wave, in addition to a signal connection through a circuit. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0039] The embodiment of the present application provides a crank-connecting rod mechanism, Figure 1 This is a schematic diagram of the structure of a crank-connecting rod mechanism provided in some embodiments of the present application. Figure 1 As shown, the crank-connecting rod mechanism is arranged in the crankcase 01. The crank-connecting rod mechanism includes: a crankshaft 02, a crank 03 and a connecting rod 04. The small end of the connecting rod 04 is connected to the piston 05, and the large end of the connecting rod 04 is connected to the first end of the crank 03. The crank 03 rotates around the crankshaft center 021. The crankshaft center 021 is the rotation center of the crankshaft 02. A protrusion 06 is provided at the edge of the second end of the crank 03. The first motion trajectory of the protrusion 06 and the second motion trajectory of the reed valve 07 intersect, so that when the crank 03 rotates around the crankshaft center 021, the protrusion 06 pushes the reed valve 07 to rebound to the closed position. Among them, the first motion trajectory of the protrusion 06 refers to the motion trajectory of the protrusion 06 when the crank 03 rotates around the crankshaft center 021 from the first position to the second position. The second motion trajectory refers to the motion trajectory of the reed valve 07 rebounding from the maximum open position to the closed position. Reference Figure 1 , the motion trajectory a is the entire motion trajectory of the protrusion 06 as the crank 03 rotates around the crankshaft center 021. It can be understood that the first motion trajectory of the protrusion 06 is Figure 1 Part of the motion trajectory a in . Figure 2 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in a first position. Figure 3 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the second position. Figure 2 and Figure 3The crank 03 is parallel to the connecting rod 04 when in the first position and the second position. When the crank 03 is in the first position, the piston 05 is located at the highest point of the upward movement. When the crank 03 is in the second position, the piston 05 is located at the lowest point of the downward movement.

[0040] In actual applications, the first motion trajectory of the protrusion 06 and the second motion trajectory of the reed valve 07 intersect, and they may intersect when the crank 03 is in the first position and the reed valve 07 is in the maximum open position. In this way, the duration of the protrusion 06 pushing the reed valve 07 to rebound to the closed position will be longer, and the rebound speed of the reed valve 07 will be faster.

[0041] It is worth noting that the embodiment of the present application does not specifically limit the shape and material of the protrusion 06. For example, the protrusion 06 can be any one of the shapes of round, oval, square, etc., or a combination of multiple shapes. For example, the protrusion 06 can be made of metal, plastic, or a composite material. Among them, the composite material can be glass fiber or nylon, etc.

[0042] In the present embodiment, since the crank 03 rotates around the crankshaft center 021, a protrusion 06 is provided at the edge of the second end of the crank 03, and the first movement trajectory of the protrusion 06 intersects with the second movement trajectory of the reed valve 07. In this way, during the normal rotation of the crank 03, the protrusion 06 can push the reed valve 07 to rebound to the closed position, thereby accelerating the rebound of the reed valve 07, thereby preventing the combustible mixture gas supplied to the engine that has entered the crankcase 01 from flowing back through the reed valve 07, causing the combustible mixture gas supplied to the engine to leak, thereby affecting the performance of the engine.

[0043] In some embodiments, the initial intersection point of the first motion trajectory of the protrusion 06 and the second motion trajectory of the reed valve 07 is located between the starting end 071 of the reed valve 07 and the midpoint 072 of the reed valve 07. The initial intersection point refers to a point where the protrusion 06 and the reed valve 07 just touch each other. It can be understood that the initial intersection point can be the starting end 071 of the reed valve 07, the initial intersection point can be the midpoint 072 of the reed valve 07, or any point between the starting end 071 of the reed valve 07 and the midpoint 072 of the reed valve 07. The starting end 071 of the reed valve 07 and the midpoint 072 of the reed valve 07 are as shown in FIG. Figure 1 shown.

[0044] In this way, the protrusion 06 can contact the reed valve 07 earlier when the crank 03 rotates around the crankshaft center 021, thereby increasing the duration of the protrusion 06 pushing the reed valve 07 to rebound, so as to make the reed valve 07 rebound faster.

[0045] In some embodiments, the surface of the protrusion 06 that contacts the reed valve 07 is a smooth surface.

[0046] In this way, the damage to the reed valve 07 when the protrusion 06 pushes the reed valve 07 to rebound can be reduced.

[0047] In some embodiments, the protrusion 06 is a square. Figure 7 A schematic diagram of another crank-connecting rod mechanism provided in some embodiments of the present application, Figure 7 The crank-connecting rod mechanism is shown when the protruding member 06 is a square. The protruding member 06 can be welded to the edge of the second end of the crank 03, or can be integrally formed with the crank 03.

[0048] Figure 8 A schematic diagram of another crank-connecting rod mechanism is provided for applying some embodiments. In some embodiments, reference is made to Figure 8 The vertex angle of the second end of the block away from the crank 03 is a circular chamfer 063.

[0049] In this way, when the block just contacts the reed valve 07 and pushes the reed valve 07 to rebound, the top corner of the block will not scratch the reed valve 07 .

[0050] In some embodiments, when the protrusion 06 pushes the reed valve 07 to rebound to the closed position, rolling friction occurs between the protrusion 06 and the reed valve 07 .

[0051] In some embodiments, reference Figure 1 The protrusion 06 may include a first shaft 061 and a first bearing 062, the first shaft 061 and the first bearing 062 cooperate with each other, the second end of the crank 03 is provided with a first accommodating hole, the first bearing 062 is provided with a second accommodating hole, the first shaft 061 passes through the second accommodating hole and is fixed to the first accommodating hole, so that the protrusion 06 is fixed to the second end of the crank 03.

[0052] In this way, rolling friction is formed between the protrusion 06 and the reed valve 07, so that the protrusion 06 causes less damage to the reed valve 07.

[0053] In some embodiments, the protrusion 06 may include a second shaft and a second bearing, the second shaft and the second bearing cooperate with each other, the second bearing is provided with a third accommodating hole, the second shaft passes through the third accommodating hole and is fixed to the surface of the second end of the crank 03, so that the protrusion 06 is fixed to the second end of the crank 03.

[0054] It is worth pointing out that the first shaft 061 and the first bearing 062 are matched, which means that the first shaft 061 can be exactly accommodated in the second accommodation hole provided on the first bearing 062, and the first bearing 062 and the first shaft 061 will not slide against each other. Similarly, the second shaft and the second bearing are matched, which means that the second shaft can be exactly accommodated in the third accommodation hole provided on the second bearing, and the second bearing and the second shaft will not slide against each other.

[0055] In some embodiments, Fig. 9 A schematic diagram of another crank-connecting rod mechanism provided in some embodiments of the present application, referring to Fig. 9 The protrusion 06 can also be an arc-shaped protrusion.

[0056] In practical applications, a avoidance member may be provided in the crankcase 01, and the size and shape of the avoidance member may match the protrusion member 06 to prevent the protrusion member 06 from contacting the crankcase 01; the avoidance member may also be provided on other structural members in the crankcase 01 to prevent the protrusion member 06 from contacting other structural members in the crankcase 01. For example, the avoidance member may be a corresponding groove provided in the crankcase 01 or on other structural members in the crankcase 01 to accommodate the protrusion member 06, so as to avoid contact with the protrusion member 06 and affect the normal rotation of the crank 03.

[0057] Alternatively, the size of the protrusion 06 can be set according to actual needs to ensure that the protrusion 06 does not contact other structural parts in the crankcase 01 except the reed valve 07 during the rotation of the crank 03.

[0058] Another embodiment of the present application further provides an engine, Figure 1 , comprising: a crankcase 01, a scavenging passage 08, a piston 05, a combustion chamber 09, an exhaust passage 10 and a crank-connecting rod mechanism provided in the first aspect of the embodiment of the present application. The crank-connecting rod mechanism is arranged in the crankcase 01, the crankcase 01 is connected to the combustion chamber 09 through the scavenging passage 08, the combustion chamber 09 is also connected to the exhaust passage 10, and the combustion chamber 09 is located on the side of the piston 05 away from the connecting rod 04.

[0059] In this embodiment, the protrusion 06 in the crank-connecting rod mechanism can push the reed valve 07 to rebound from the maximum open position to the closed position. In this way, the rebound of the reed valve 07 can be accelerated, thereby preventing the combustible mixture gas supplied to the engine that has entered the crankcase 01 from flowing back through the reed valve 07, causing the combustible mixture gas supplied to the engine to leak and affecting the performance of the engine.

[0060] The specific process of the protrusion 06 pushing the reed valve 07 to rebound to the closed position is described below in conjunction with the working process of the engine.

[0061] When the crank 03 is in the second position, due to the inertia of the crank 03, the crank 03 will continue to rotate toward the first position along the motion trajectory a, and the crank 03 drives the connecting rod 04 to push the piston 05 upward. As the piston 05 moves upward, the volume of the crankcase 01 continues to increase and the pressure continues to decrease. When the pressure in the crankcase 01 decreases to a value lower than the pressure in the intake passage 11, the reed valve 07 gradually opens. Figure 4 A schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the third position, with reference to Figure 4, the gas in the intake passage 11 begins to enter the crankcase 01. The piston 05 continues to move upward, Figure 5 This is a schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the fourth position, with reference to Figure 5 As the piston 05 moves upward, the piston 05 closes the scavenging passage 08 and the exhaust passage 10, and ignition begins in the combustion chamber 09. When the crank 03 is in the first position, the pressure in the crankcase 01 is close to the pressure in the intake passage 11, and the reed valve 07 is opened to the maximum opening position. At this time, the pressure in the combustion chamber 09 increases due to the combustion of gas, and then, the piston 05 is pushed downward, and the piston 05 drives the connecting rod 04 downward, and the connecting rod 04 pushes the crank 03 to rotate from the first position to the second position. At this time, the volume in the crankcase 01 gradually decreases, and the pressure in the crankcase 01 increases to be greater than the pressure in the intake passage 11, and the reed valve 07 gradually closes. Reference Figure 1 During this process, since the first motion trajectory of the protrusion 06 and the second motion trajectory of the reed valve 07 intersect, when the crank 03 rotates around the crankshaft center 021, the protrusion 06 can push the reed valve 07 to rebound to the closed position to accelerate the rebound of the reed valve 07. Figure 6 This is a schematic diagram of a crank of a crank-connecting rod mechanism provided in some embodiments of the present application when the crank is in the fifth position, with reference to Figure 6 , the reed valve 07 is closed, and as the piston 05 moves downward, the exhaust passage 10 is connected to the combustion chamber 09, and the burned gas in the combustion chamber 09 is discharged through the exhaust passage 10. The piston 05 continues to move downward, the scavenging passage 08 is connected to the combustion chamber 09, and the combustible mixture supplied to the engine in the crankcase 01 enters the combustion chamber 09 through the scavenging passage 08, sweeping the burned gas inside the combustion chamber 09 out of the combustion chamber 09 through the exhaust passage 10. The piston 05 continues to drive the connecting rod 04 downward until the connecting rod 04 pushes the crank 03 to the second position, and then, as in the above process, due to the inertia of the crank 03, the crank 03 will continue to rotate to the first position along the motion trajectory a. In this way, during the operation of the engine, the protrusion 06 can push the reed valve 07 to rebound to the closed position to accelerate the rebound of the reed valve 07.

[0062] It is worth pointing out that the weight of the crank 03 provided in the embodiment of the present application should not be increased too much compared with the conventional crank 03, thereby affecting the power-to-weight ratio of the engine.

[0063] Those skilled in the art will appreciate that, although some embodiments herein include certain features included in other embodiments, the combination of features of different embodiments is meant to be within the scope of the present application and form different embodiments. For example, in the claims, any one of the claimed embodiments may be used in any combination.

[0064] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A crank-connecting rod mechanism, characterized in that: The crank-connecting rod mechanism is arranged in the crankcase, and the mechanism comprises: a crankshaft, a crank and a connecting rod; The small end of the connecting rod is connected to the piston, and the large end of the connecting rod is connected to the first end of the crank, and the crank rotates around the center of the crankshaft, and the center of the crankshaft is the rotation center of the crankshaft. A protrusion is provided at the edge of the second end of the crank, and the first movement trajectory of the protrusion and the second movement trajectory of the reed valve intersect, so that when the crank rotates around the center of the crankshaft, the protrusion pushes the reed valve to rebound to the closed position, wherein the first movement trajectory of the protrusion refers to the movement trajectory of the protrusion when the crank rotates around the center of the crankshaft from the first position to the second position, and the second movement trajectory refers to the movement trajectory of the reed valve when it rebounds from the maximum open position to the closed position.

2. The mechanism according to claim 1, characterized in that: An initial intersection point of the first motion trajectory of the protruding member and the second motion trajectory of the reed valve is located between the starting end of the reed valve and the midpoint of the reed valve.

3. The mechanism according to claim 1, characterized in that: The surface of the protruding member in contact with the reed valve is a smooth surface.

4. The mechanism according to claim 1, characterized in that: The protruding piece is a square.

5. The mechanism according to claim 4, characterized in that: The top angle of the second end of the block away from the crank is a circular arc chamfer.

6. The mechanism according to claim 1, characterized in that: When the protrusion pushes the reed valve to rebound to the closed position, rolling friction occurs between the protrusion and the reed valve.

7. The mechanism according to claim 6, characterized in that The protrusion includes a first shaft and a first bearing, the first shaft and the first bearing cooperate with each other, a first accommodating hole is provided at the second end of the crank, a second accommodating hole is provided on the first bearing, the first shaft passes through the second accommodating hole and is fixed to the first accommodating hole, so that the protrusion is fixed to the second end of the crank.

8. The mechanism according to claim 6, characterized in that: The protrusion includes a second shaft and a second bearing, the second shaft and the second bearing cooperate with each other, the second bearing is provided with a third accommodating hole, the second shaft passes through the third accommodating hole and is fixed to the surface of the second end of the crank, so that the protrusion is fixed to the second end of the crank.

9. An engine, characterized in that: The engine includes a crankcase, a scavenging passage, a piston, a combustion chamber, an exhaust passage and a crank-connecting rod mechanism as described in any one of claims 1 to 8, wherein the crank-connecting rod mechanism is arranged in the crankcase, the crankcase is connected to the combustion chamber through the scavenging passage, the combustion chamber is also connected to the exhaust passage, and the combustion chamber is located on the side of the piston away from the connecting rod.

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