Piston, combustion system and engine
By designing combustion pits and staggered injector arrangements in opposed piston engines, the problem of uneven fuel injection in the combustion chamber is solved, achieving full fuel diffusion and efficient combustion, thus improving combustion efficiency and thermal efficiency.
Patent Information
- Application Number
- CN202520316534.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-26
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2035-02-26
AI Technical Summary
In existing opposed piston engines, the fuel injectors in the combustion chamber spray fuel in opposite directions, resulting in localized areas that are either too rich or too lean, leading to poor combustion and limited thermal efficiency.
The piston's combustion pits are arranged symmetrically around the central axis at a 180° rotation. The injectors correspond one-to-one with the combustion pits. The combustion pits are staggered and extended in length. The injectors spray fuel into the combustion pits, and the flame develops along the extension direction of the pits, reducing the probability of flame collision and promoting fuel diffusion.
It improves combustion efficiency and thermal efficiency, reduces the probability of flame collision within the combustion pit, promotes full fuel diffusion, protects the piston top surface, and enhances the performance of the combustion system.
Smart Images
Figure CN223578057U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of engine technology, and in particular to a piston, combustion system and engine. Background Technology
[0002] To alleviate the energy crisis and environmental pollution, improving thermal efficiency and reducing emissions are imperative. To this end, existing technology proposes an opposed piston engine. Specifically, the combustion chamber structure of the opposed piston engine includes a cylinder liner and two pistons that are axially movable and axially distributed within the cylinder liner. The pistons have a central recess, and two conical recesses are arranged on opposite sides of the central recess. Two fuel injectors inject fuel into the central recess through the two conical recesses in a one-to-one correspondence. The central recess serves as the main combustion chamber for fuel diffusion and combustion.
[0003] Two fuel injectors are installed on the cylinder liner at a 180° angle. The fuel injected by the two fuel injectors travels towards each other and collides in the combustion chamber, resulting in localized areas of excessive richness and excessive leanness. As a result, the fuel cannot diffuse sufficiently in the combustion chamber, leading to poor combustion and limited thermal efficiency. Utility Model Content
[0004] The purpose of this invention is to provide a piston, combustion system, and engine that can improve combustion efficiency and the thermal efficiency of the combustion system.
[0005] To achieve this objective, the present invention adopts the following technical solution:
[0006] A piston includes a piston body, the piston body having a top surface, the top surface having two combustion pits, the two combustion pits being arranged in a 180° rotational symmetry about the central axis of the piston body;
[0007] One end of the combustion pit extends to the outer peripheral wall of the piston body to form an injection port; the projection of the combustion pit on a plane perpendicular to the axial direction of the piston body is a first projection, the extension axis of the first projection intersects the outer peripheral wall of the piston body at point A, and the line connecting the two points A is arranged at an angle to the extension axis of any of the first projections; the end of any combustion pit away from its own injection port and the injection port of another combustion pit are located on the same side of a preset plane, the preset plane is perpendicular to the line connecting the two points A and the central axis of the piston body is located in the preset plane.
[0008] As one possible implementation of the piston described above, the cross-sectional area of the combustion pit gradually increases along the extension direction of the first projection, which is the direction from one end of the combustion pit where the injection port is located to the other end.
[0009] As an implementable solution of the piston, the angle between the line connecting the two A points and the extension axis of any of the first projections is θ, 0 < θ < 45°.
[0010] As an implementable solution of the piston, the two combustion pits are arranged at intervals.
[0011] Or, the inner walls of the two combustion pits directly abut and the abutting position is lower than the top surface, and the abutting position is located at one end of the combustion pit away from the incident port.
[0012] As an implementable solution of the piston, the abutting line between the combustion pit and the top surface comprises:
[0013] Two straight line segments;
[0014] A circular arc, and the two straight line segments are connected by the circular arc at one end away from the incident port.
[0015] As an implementable solution of the piston, the length of the straight line segment is L1, the radius of the piston body is d, and d < L1 < 2d;
[0016] And / or, the maximum length of the abutting inner walls of the two combustion pits is L2, the radius of the piston body is d, and 0 < L2 < d;
[0017] And / or, the angle between the two straight line segments of the same combustion pit is α, and 0 < α < 45°;
[0018] And / or, the radius of the circular arc is R, the radius of the piston body is d, and d / 5 < R < d / 3.
[0019] As an implementable solution of the piston, the cross section of the combustion pit perpendicular to the extension direction thereof is a semicircle or a semi-ellipse.
[0020] As an implementable solution of the piston, along the extension direction of the combustion pit, the width of the combustion pit gradually increases;
[0021] And / or, along the extension direction of the combustion pit, the depth of the combustion pit gradually increases.
[0022] In order to achieve the above-mentioned purpose, the utility model also provides a combustion system, including cylinder sleeve and the piston of any scheme, the piston hole is equipped in the cylinder sleeve, the two pistons along the axial direction of the piston hole are movable, the top surface of two pistons is opposite to the axial direction of the piston, and the inner wall of the piston hole between two pistons and two pistons is surrounded to form a combustion chamber.
[0023] The combustion system further comprises two injectors arranged between the two pistons along the axial direction of the pistons, and the two injectors are arranged one-to-one with the two combustion pits of each piston, and the two injectors are used for injecting fuel into the combustion chamber.
[0024] In order to achieve the above-mentioned purpose, the utility model further provides an engine comprising the combustion system.
[0025] The utility model discloses a piston, combustion system and engine, two pistons and the inner peripheral wall of the piston hole between two pistons enclose the combustion chamber, two combustion pits are arranged around the central axis of the piston body 180 rotation symmetry, and the line of two A points is arranged with the included angle of any first projection's extension axis, and the end of any combustion pit away from the incident port and the incident port of another combustion pit are located on the same side of the preset plane, so that two combustion pits are arranged in dislocation, and the length of single combustion pit along the extension direction of itself is prolonged, the injector is in the incident port and sprays fuel into the combustion pit, and the flame formed by the combustion of the fuel sprayed into the combustion pit develops along the extension direction of the combustion pit, which not only prolongs the path of the flame circulating in the combustion pit, but also greatly reduces the probability of the flame colliding in the combustion pit, so that the fuel fully diffuses in the combustion pit, the combustion of the fuel is basically carried out in the combustion pit, which is beneficial to protecting the top surface of the piston and improving the combustion efficiency. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 It is the top surface schematic view of the piston provided by the utility model embodiment one.
[0027] Figure 2 It is the sectional view of the combustion system provided by the utility model embodiment one.
[0028] Figure 3 It is the development schematic view of the flame in the combustion chamber when the combustion system carries out combustion simulation.
[0029] Figure 4 It is the top surface schematic view of the piston provided by the utility model embodiment two.
[0030] Figure 5 It is the sectional view of the combustion system provided by the utility model embodiment two.
[0031] In the drawing:
[0032] 1, piston; 11, top surface; 12, combustion pit; 2, cylinder sleeve; 3, injector;
[0033] 100, preset plane. DETAILED DESCRIPTION
[0034] The utility model will be described in further detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are merely intended to explain the utility model and not to limit the utility model. In addition, it should be noted that only the parts related to the utility model are shown in the drawings for ease of description, not all the structures.
[0035] In the description of the utility model, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the communication between two elements or the interaction relationship between two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.
[0036] In the utility model, unless otherwise explicitly specified and limited, the "upper" or "lower" of the first feature to the second feature can include that the first and second features are in direct contact, or the first and second features are not in direct contact but are in contact through another feature between them. Moreover, the "upper", "upper" and "upper" of the first feature to the second feature include that the first feature is directly above and obliquely above the second feature, or only indicates that the horizontal height of the first feature is higher than that of the second feature. The "below", "below" and "below" of the first feature to the second feature include that the first feature is directly below and obliquely below the second feature, or only indicates that the horizontal height of the first feature is less than that of the second feature.
[0037] In the description of the embodiment, the terms "upper", "lower", "right", etc. orientation or positional relationship is based on the orientation or positional relationship shown in the drawings, only for the convenience of description and simplification of operation, and does not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore it cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.
[0038] Embodiment one
[0039] As shown in Figure 1 and Figure 2 The utility model provides a kind of piston, combustion system comprising the piston and engine comprising the combustion system, wherein, combustion system further include cylinder liner 2 and injector 3, cylinder liner 2 is equipped with piston hole, two pistons 1 movable along its axial direction are equipped in piston hole, piston 1 includes piston body, piston body has top surface 11, the top surface 11 of two pistons 1 is oppositely arranged along the axial direction of piston 1, two pistons 1 and the inner circumferential wall between two pistons 1 in piston hole surround combustion chamber.
[0040] The two combustion pits 12 are arranged in 180° rotational symmetry around the central axis of the piston 1, one end of the combustion pit 12 extends to the outer peripheral wall of the piston body to form an injection port, the projection of the combustion pit 12 on the plane perpendicular to the axial direction of the piston body is a first projection, the extension axis of the first projection intersects the outer peripheral wall of the piston body at point A, and the line connecting the two A points is arranged at an angle with the extension axis of any first projection. The end of any combustion pit 12 away from its own injection port and the injection port of the other combustion pit 12 are located on the same side of the preset plane 100, and the preset plane 100 is perpendicular to the line connecting the two A points and the central axis of the piston body is located in the preset plane 100.
[0041] The combustion system further comprises two injectors 3 arranged between the two pistons 1 in the axial direction of the piston 1; the two injectors 3 are arranged one-to-one corresponding to the two combustion pits 12 of each piston 1, and the injector 3 is used to inject fuel into the combustion chamber. Exemplarily, the two injectors 3 are arranged in 180° rotational symmetry around the central axis of the piston 1, and the projections of the two combustion pits 12 corresponding to the same injector 3 on the plane perpendicular to the axial direction of the piston 1 are completely coincident. The projection of the injection end of the injector 3 on the plane where the top surface 11 is located is an injection projection, and the injection projection is located within the projection of the corresponding combustion pit 12 on the plane where the top surface 11 is located.
[0042] As shown in Figures 1 to 3 The two combustion pits 12 are arranged in 180° rotational symmetry around the central axis of the piston body, and the line connecting the two A points is arranged at an angle with the extension axis of any first projection, and the end of any combustion pit 12 away from its own injection port and the injection port of the other combustion pit 12 are located on the same side of the preset plane 100, so that the two combustion pits 12 are arranged in staggered manner, and the length of a single combustion pit 12 in its extension direction is extended. The injector 3 injects fuel into the combustion pit 12 at the injection port, and the flame formed by the combustion of the fuel injected into the combustion pit 12 develops along the extension direction of the combustion pit 12, not only extending the path of the flame circulating in the combustion pit 12, but also greatly reducing the probability of flame collision in the combustion pit 12, so that the fuel is fully diffused in the combustion pit 12, greatly reducing the area of the combustion pit 12 where the fuel is too thick or too thin, and the combustion of the fuel is basically carried out in the combustion pit 12, which is beneficial to protect the top surface 11 of the piston 1 and improve the combustion efficiency.
[0043] In order to improve the fuel and air mixing uniformity, the vortex intake is generally used when the air enters the combustion chamber, so that the air entering the combustion chamber flows in the form of vortex. When the in-cylinder vortex is relatively large, the flame beams formed by the fuel injected into the combustion chamber by the two injectors 3 are prone to collide. When the in-cylinder vortex is relatively small, the flame beams formed by the fuel injected into the combustion chamber by the two injectors 3 are not prone to collide. In view of this, further, for the engine with relatively small in-cylinder vortex, such as the engine with in-cylinder vortex ratio less than 1.8, the inner walls of the two combustion pits 12 directly abut and the abutting position is lower than the top surface 11, and the abutting position is at the end of the combustion pit 12 away from the incident port of itself. By arranging in this way, the two combustion pits 12 of the same piston 1 are connected, which can further prolong the flame flow path on the basis of reducing the probability of flame collision in the two combustion pits 12, and improve the mixing uniformity of fuel and air and the fuel combustion completeness.
[0044] Figure 3 The development of the flame in the combustion system provided by the embodiment is illustrated, and it can be seen that the flames in the two combustion pits 12 do not collide.
[0045] Further, the maximum length of the inner walls of the two combustion pits 12 directly abutting is L2, and 0 < L2 < d. The size of L2 is determined by the in-cylinder vortex ratio of the engine.
[0046] Further, the cross-sectional area of the combustion pit 12 gradually increases along the extension direction of the first projection, and the extension direction of the first projection is the direction from one end of the combustion pit 12 provided with the incident port to the other end. By limiting the cross-sectional area of the combustion pit 12 gradually increasing along the extension direction of the first projection, the shape of the combustion pit 12 is suitable for the development of the flame, which is conducive to the more uniform mixing of fuel and air in the combustion pit 12, and improves the thermal efficiency.
[0047] Further, the abutting line of the combustion pit 12 and the top surface 11 includes two straight line segments and a circular arc, and the two straight line segments away from the incident port are connected by the circular arc. By arranging in this way, it is conducive to making the shape of the combustion pit 12 more consistent with the development of the flame.
[0048] Specifically, the line connecting the two A points intersects and is perpendicular to the central axis of the piston body, and the center of the circular arc and the line connecting the A points is the extension axis of the corresponding combustion pit 12. Exemplarily, the central angle of the circular arc is greater than or equal to 180°, and the circular arc is symmetrically arranged about the extension axis of the combustion pit 12.
[0049] Further, along the extending direction of the combustion pit 12, the depth of the combustion pit 12 gradually increases, and the width of the combustion pit 12 gradually increases, which conforms to the flame development trend, is beneficial to the full diffusion of the fuel in the process of flowing in the combustion pit 12, and the flame no longer goes forward after colliding with the inner wall of the end of the combustion pit 12, the maximum depth of the end of the combustion pit 12 is maximum, which is beneficial to reduce the probability of the flame rolling out of the combustion pit 12 under the action of the inner wall of the combustion pit 12.
[0050] Exemplarily, the cross section of the combustion pit 12 perpendicular to the extending direction of the combustion pit 12 is a semicircle. In other embodiments, the cross section of the combustion pit 12 perpendicular to the extending direction of the combustion pit 12 can also be a semi-ellipse, the long axis direction of the ellipse is the width direction of the combustion pit 12, and the short axis direction of the ellipse is the depth direction of the combustion pit 12.
[0051] Further, the length of the straight line segment is L1, the radius of the piston body is d, d < L1 < 2d, and the size of L1 is determined by the fuel penetration distance. L1 can be selected as any value greater than d and less than 2d, such as 1.1d, 1.2d, 1.3d, 1.4d, 1.5d, 1.6d, 1.7d, 1.8d and 1.9d.
[0052] The radius of the circular arc is R, and the radius of the piston body is d, d / 5 < R < d / 3. The size of R is determined by the fuel diffusion capacity. The included angle between the two straight line segments of the same combustion pit 12 is α, and 0 < α < 45°. The size of the included angle α is determined by the combustion and diffusion of the fuel in the combustion pit 12. The diameter of the incident port is D, which is determined by the diameter of the injector 3.
[0053] The embodiment also provides a design method of the above-mentioned combustion system to optimize the design of the above-mentioned various parameters. The design method of the combustion system comprises the following steps:
[0054] S1, constructing a three-dimensional model of the combustion system;
[0055] S2, performing three-dimensional combustion simulation and mixed distribution cloud simulation based on the three-dimensional model of the combustion system;
[0056] S3, judging whether the fuel injected by the two injectors 3 collides at the center of the piston 1, if yes, increasing the included angle θ, and then returning to S2; if no, performing S4;
[0057] S4, judging whether the fuel injection process touches the inner wall of the end of the combustion pit 12, if yes, increasing L1, and then returning to S2; if no, performing S5;
[0058] S5, judging whether the fuel distribution in the straight line segment is uniform, if not, reducing the included angle a when the fuel distribution in the straight line segment is too lean, increasing the included angle a when the fuel distribution in the straight line segment is too dense, and then returning to S2; if not, executing S6;
[0059] S6, judging whether the fuel distribution in the circular arc segment is uniform, if not, reducing the radius R when the fuel distribution in the circular arc segment is too lean, increasing the radius R when the fuel distribution in the circular arc segment is too dense, and then returning to S2; if not, completing the parameter optimization of the combustion system.
[0060] The design method of the combustion system provided by the embodiment can quickly design the combustion system required by different engine models, realize the optimization design of the combustion system through three-dimensional combustion simulation and mixed distribution cloud simulation, and has shorter time and lower cost compared with test selection.
[0061] Embodiment two
[0062] The difference between the embodiment and the embodiment one is that, as shown in Figure 4 and Figure 5 For the engine with relatively large in-cylinder swirl, the airflow velocity in the combustion chamber is large, and the probability of flame collision in the two combustion pits 12 is relatively large. In view of this, for the engine with an in-cylinder swirl ratio not less than 1.8, the two combustion pits 12 are arranged at intervals. In other words, the two combustion pits 12 are arranged at intervals, so that the fuel injected by the two injectors 3 is burned in the respective corresponding combustion pits 12, further reducing the probability of flame collision in the two combustion pits 12.
[0063] Obviously, the above embodiments of the utility model are only examples for clearly explaining the utility model, and are not the limitation of the embodiments of the utility model. For ordinary skilled in the art, various obvious changes, re-adjustment and replacement can be made without departing from the protection scope of the utility model. Here, it is not necessary and impossible to enumerate all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the utility model claim.
Claims
1. A piston, comprising a piston body having a top surface (11) and two combustion pits (12) provided thereon, characterized in that, The two combustion pits (12) are arranged symmetrically about the central axis of the piston body at 180° rotation; One end of the combustion pit (12) extends to the outer peripheral wall of the piston body to form an injection port; the projection of the combustion pit (12) on a plane perpendicular to the axial direction of the piston body is a first projection, the extension axis of the first projection intersects the outer peripheral wall of the piston body at point A, and the line connecting the two points A is arranged at an angle to the extension axis of any of the first projections; the end of any combustion pit (12) away from its own injection port and the injection port of another combustion pit (12) are located on the same side of a preset plane (100), the preset plane (100) is perpendicular to the line connecting the two points A and the central axis of the piston body is located in the preset plane (100).
2. The piston according to claim 1, characterized in that, The cross-sectional area of the combustion pit (12) gradually increases along the extension direction of the first projection, which is the direction from one end of the combustion pit (12) where the incident port is located to the other end.
3. The piston according to claim 1, characterized in that, The angle between the line connecting the two points A and the extended axis of any of the first projections is θ, where 0 < θ < 45°.
4. The piston according to claim 1, characterized in that, The two combustion pits (12) are spaced apart; Alternatively, the inner walls of the two combustion pits (12) are directly connected and the connection position is lower than the top surface (11), and the connection position is located at the end of the combustion pit (12) away from its own incident port.
5. The piston according to claim 1, characterized in that, The connection line between the combustion pit (12) and the top surface (11) includes: Two straight line segments; An arc, in which the ends of the two straight segments furthest from the incident port are connected by the arc.
6. The piston according to claim 5, characterized in that, The length of the straight segment is L1, and the radius of the piston body is d, where d < L1 < 2d; And / or, the maximum length of the inner walls of the two combustion pits (12) directly connected is L2, and the radius of the piston body is d, 0 < L2 < d; And / or, the included angle between two straight segments of the same combustion pit (12) is α, 0 < α < 45°; And / or, the radius of the arc is R, and the radius of the piston body is d, where d / 5 < R < d / 3.
7. The piston according to claim 5, characterized in that, The combustion pit (12) has a semicircle or semi-ellipse in cross section perpendicular to its extension direction.
8. The piston according to any one of claims 1 to 7, characterized in that, Along the extending direction of the combustion pit (12), the width of the combustion pit (12) gradually increases; And / or, along the extension direction of the combustion pit (12), the depth of the combustion pit (12) gradually increases.
9. A combustion system, characterized in that, Includes a cylinder liner (2) and a piston (1) as described in any one of claims 1 to 8, wherein the cylinder liner (2) is provided with a piston hole, and two pistons (1) are provided in the piston hole that are movable along its axial direction, the top surfaces (11) of the two pistons (1) are arranged opposite to each other along the axial direction of the pistons (1), and the inner peripheral wall of the piston hole between the two pistons (1) and the two pistons (1) forms a combustion chamber; The combustion system also includes two injectors (3), which are arranged between the two pistons (1) along the axial direction of the piston (1). The two injectors (3) are arranged in a one-to-one correspondence with the two combustion pits (12) of each piston (1). The injectors (3) are used to inject fuel into the combustion chamber.
10. An engine, characterized in that, Includes the combustion system as described in claim 9.