Small two-stroke chain saw gasoline engine with flat combustion chamber
By adjusting the combustion chamber structure, appropriately increasing the distance between the upper wall of the combustion chamber and the piston edge, and adopting a spherical and conical transition design, the problem of carbon buildup causing engine seizure was solved, thereby improving engine power and thermal efficiency.
Patent Information
- Application Number
- CN202520400327.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-07
- Publication Date
- 2026-02-10
- Estimated Expiration
- 2035-03-07
AI Technical Summary
The combustion chamber edge of existing two-stroke small gasoline engines is too flat, which easily leads to carbon buildup, causing the piston to seize up, reducing the working area of the combustion chamber, and reducing engine power.
The distance S1 between the upper wall edge of the combustion chamber and the upper surface edge of the piston is set to 1/18-1/10 of the cylinder inner diameter. A spherical, conical, and concave curved surface transition design is adopted to ensure that the combustion chamber volume remains unchanged and the height of the top of the combustion chamber is reduced to ensure that the engine compression ratio remains unchanged.
It effectively prevents carbon buildup from seizing the engine, increases the combustion chamber's working area, improves engine power and thermal efficiency, and ensures efficient mechanical energy transfer.
Smart Images
Figure CN223894257U_ABST
Abstract
Description
Technical fields:
[0001] This utility model belongs to the field of engine technology, specifically referring to a two-stroke small gasoline engine for chainsaws with a flat combustion chamber. Background technology:
[0002] Existing two-stroke small gasoline engines include a cylinder 1, inside which a piston 2 slides. A combustion chamber 3 is formed above the piston 2 within the cylinder 1. The combustion chamber 1 is basically hat-shaped, meaning the central part is spherical, gradually flattening outwards until it reaches its flattest point at the cylinder edge. The height of the cylinder edge is typically 1 / 27 to 1 / 20 of the cylinder diameter. Figure 1 As shown. Its shortcomings are: 1. The edges are too flat, and carbon buildup can easily cause them to seize up with the piston (when the piston reaches top dead center), resulting in insufficient engine power or machine malfunction. The cylinder must be opened promptly to clean the carbon deposits in the combustion chamber to restore normal operation. 2. After carbon buildup on the edges of the combustion chamber, the combustible mixture cannot flow to the original outermost area and can only concentrate in the area near the center. The working diameter of the combustion chamber decreases, and the area that pushes the piston downwards during combustion decreases. The instantaneous explosive thrust is also proportionally reduced with the decrease in area, leading to a reduction in engine power. Summary of the Invention:
[0003] The purpose of this invention is to provide a two-stroke small gasoline engine for chainsaws with a flat combustion chamber, in which the piston will not be jammed by carbon deposits, the combustible mixture can flow in the area, the working diameter of the combustion chamber is large, the area that pushes the piston downward when the power is burning is large, the instantaneous explosion thrust is large, and thus the engine power is high.
[0004] This utility model is implemented as follows:
[0005] A two-stroke chainsaw gasoline engine with a flat combustion chamber includes a cylinder, in which a piston is slidably disposed. A combustion chamber is formed in the cylinder above the piston. When the piston is at top dead center, the distance S1 between the edge of the upper wall of the combustion chamber and the edge of the upper surface of the piston is 1 / 18 to 1 / 10 of the cylinder inner diameter D.
[0006] In the aforementioned two-stroke chainsaw gasoline engine with a flat combustion chamber, when the piston is at top dead center, the distance S1 between the edge of the upper wall of the combustion chamber and the edge of the upper surface of the piston is 1 / 16 to 1 / 14 of the cylinder inner diameter D.
[0007] In the aforementioned two-stroke chainsaw gasoline engine with a flat combustion chamber, the way to ensure that the volume of the combustion chamber remains unchanged can be by lowering the height of the top of the combustion chamber or by reducing the diameter of the middle part of the combustion chamber.
[0008] In the aforementioned two-stroke chainsaw small gasoline engine with a flat combustion chamber, the upper wall surface includes a spherical surface in the middle, a conical surface at the edge, and an inwardly concave curved surface connecting the spherical surface and the conical surface. The lower end of the conical surface transitions to the side wall surface of the combustion chamber through an arc surface.
[0009] In the aforementioned two-stroke chainsaw small gasoline engine with a flat combustion chamber, when the piston is at top dead center, the distance S2 between the highest point of the spherical surface and the highest point of the upper surface is 12mm-15mm.
[0010] In the aforementioned two-stroke chainsaw gasoline engine with a flat combustion chamber, the radius R of the sphere is 11mm-12mm.
[0011] The outstanding advantages of this utility model compared to the prior art are:
[0012] 1. In this invention, the distance S1 between the upper wall edge of the combustion chamber and the upper surface edge of the piston is set to 1 / 18-1 / 10 of the cylinder inner diameter D. This effectively increases the distance between the upper wall edge of the combustion chamber and the upper surface edge of the piston, providing ample space. Even if carbon deposits are generated, the piston will not be jammed by the carbon deposits. The combustible mixture can also flow in this area. The combustion chamber has a large working diameter, resulting in a large area for pushing the piston downward during power combustion, a large instantaneous explosion thrust, and thus high engine power.
[0013] 2. The distance S2 between the highest point of the spherical surface and the highest point of the upper surface of this utility model is 12mm-15mm, which effectively reduces the height of the top of the combustion chamber to ensure that the volume of the combustion chamber remains unchanged, thereby ensuring that the compression ratio of the engine remains unchanged. The basic parameters and functions of the power can be guaranteed, and the mechanical energy transmission is efficient and the thermal efficiency is high. Attached image description:
[0014] Figure 1 This is a structural diagram of existing technology;
[0015] Figure 2 This is a schematic diagram of the structure of this utility model;
[0016] Figure 3 This is a schematic diagram of the spark plug-free structure of this utility model.
[0017] Figure label:
[0018] Figure 1 In the middle: 1. Cylinder; 2. Piston; 3. Combustion chamber.
[0019] Figure 2 , 3 In the middle: 11, cylinder; 12, piston; 13, combustion chamber; 14, upper wall surface; 14a, spherical surface; 14b, conical surface; 14c, concave curved surface; 15, upper surface; 16, side wall surface; 17, arc surface. Detailed implementation method:
[0020] The present invention will be further described below with reference to specific embodiments. See also: Figure 2 —3:
[0021] A two-stroke chainsaw gasoline engine with a flat combustion chamber includes a cylinder 11, in which a piston 12 is slidably disposed. A combustion chamber 13 is formed in the cylinder 11 above the piston 12. When the piston 12 is at top dead center, the distance S1 between the edge of the upper wall surface 14 of the combustion chamber 13 and the edge of the upper surface 15 of the piston 12 is 1 / 18 to 1 / 10 of the inner diameter D of the cylinder 11.
[0022] like Figure 2 , 3 As shown, this utility model sets the distance S1 between the edge of the upper wall 14 of the combustion chamber 13 and the edge of the upper surface 15 of the piston 12 to 1 / 18-1 / 10 of the inner diameter D of the cylinder 11. This effectively increases the distance between the edge of the upper wall 14 of the combustion chamber 13 and the edge of the upper surface 15 of the piston 12. With sufficient space, even if carbon deposits are generated, the piston 12 will not be blocked by the carbon deposits. The combustible mixture can also flow in this area. The working diameter of the combustion chamber is large, and the area that pushes the piston downward when the power combustion is performed is large, resulting in a large instantaneous explosion thrust, which in turn leads to high engine power.
[0023] Furthermore, when the piston 12 is at top dead center, the distance S1 between the edge of the upper wall surface 14 of the combustion chamber 13 and the edge of the upper surface 15 of the piston 12 is 1 / 16 to 1 / 14 of the inner diameter D of the cylinder 11. In this embodiment, when the piston 12 is at top dead center, the distance between the edge of the upper wall surface 14 of the combustion chamber 13 and the edge of the upper surface 15 of the piston 12 is 1 / 15 of the inner diameter of the cylinder 11.
[0024] The structure of the upper wall 14 of the combustion chamber 13: as follows Figure 2 , 3 As shown, the upper wall surface 14 includes a spherical surface 14a located in the middle, a conical surface 14b located at the edge, and an inwardly concave curved surface 14c connecting the spherical surface 14a and the conical surface 14b. The lower end of the conical surface 14b transitions to the side wall surface 16 of the combustion chamber 13 through an arc surface 17.
[0025] The distance between the edge of the upper wall 14 of the combustion chamber 13 and the edge of the upper surface 15 of the piston 12 is the same as the distance between the lower end point of the cone 14b and the edge of the upper surface 15 of the piston 12.
[0026] To ensure that the volume of combustion chamber 13 remains constant, such as Figure 3As shown, when the piston 12 is at top dead center, the distance S2 between the highest point of the spherical surface 14a and the highest point of the upper surface 15 is 12mm-15mm. This effectively reduces the height of the top of the combustion chamber 13 to ensure that the volume of the combustion chamber 13 remains constant, thereby ensuring that the engine compression ratio remains constant, and thus guaranteeing the basic parameters and functionality of the power. In this embodiment, when the piston 12 is at top dead center, the distance S2 between the highest point of the spherical surface 14a and the highest point of the upper surface 15 is 14mm.
[0027] As the top of the combustion chamber 13 is lowered, the spark plug mounting position is also moved downwards, bringing the spark plug's ignition electrode closer to the center of the piston 12. This design helps the engine achieve more efficient mechanical energy transfer in each stroke, resulting in higher thermal efficiency.
[0028] When the distance S1 between the edge of the upper wall 14 of the combustion chamber 13 and the edge of the upper surface 15 of the piston 12 is 1 / 18 to 1 / 10 of the inner diameter D of the cylinder 11, the top height of the combustion chamber 13 does not need to be lowered too much, provided that the piston 13 does not collide with carbon deposits and the air-fuel mixture can flow at the edge of the combustion chamber 13.
[0029] Preferably, the radius R of the sphere 14a is 11mm-12mm. In this embodiment, the radius R of the sphere 14a is 11.5mm.
[0030] The above embodiments are only one of the preferred embodiments of this utility model and are not intended to limit the scope of implementation of this utility model. Therefore, all equivalent changes made in accordance with the shape, structure and principle of this utility model should be covered within the protection scope of this utility model.
Claims
1. A two-stroke gasoline engine for chainsaws with a flat combustion chamber, comprising a cylinder (11), wherein a piston (12) is slidably disposed within the cylinder (11), and a combustion chamber (13) is formed within the cylinder (11) above the piston (12), characterized in that: When the piston (12) is at top dead center, the distance between the edge of the upper wall (14) of the combustion chamber (13) and the edge of the upper surface (15) of the piston (12) is 1 / 18 to 1 / 10 of the inner diameter of the cylinder (11).
2. The two-stroke small gasoline engine for chainsaws with a flat combustion chamber according to claim 1, characterized in that: When the piston (12) is at top dead center, the distance between the edge of the upper wall (14) of the combustion chamber (13) and the edge of the upper surface (15) of the piston (12) is 1 / 16 to 1 / 14 of the inner diameter of the cylinder (11).
3. A two-stroke small gasoline engine for chainsaws with a flat combustion chamber according to claim 1, characterized in that: The upper wall surface (14) includes a spherical surface (14a) located in the middle, a conical surface (14b) located at the edge, and an inwardly concave curved surface (14c) connecting the spherical surface (14a) and the conical surface (14b). The lower end of the conical surface (14b) transitions to the side wall surface (16) of the combustion chamber (13) through an arc surface (17).
4. A two-stroke small gasoline engine for chainsaws with a flat combustion chamber according to claim 3, characterized in that: When the piston (12) is at the top dead center, the distance between the highest point of the spherical surface (14a) and the highest point of the upper surface (15) is 12mm-15mm.
5. A two-stroke small gasoline engine for chainsaws with a flat combustion chamber according to claim 3, characterized in that: The radius of the sphere (14a) is 11mm-12mm.