Pre-combustion chamber structure and engine

Abstract

The utility model discloses a precombustion chamber structure and engine relates to vehicle technical field, precombustion chamber structure includes: precombustion chamber shell, precombustion chamber shell defines precombustion chamber, precombustion chamber shell includes side wall and bottom wall, the thickness of side wall is greater than the thickness of bottom wall, precombustion chamber shell is provided with through hole, precombustion chamber shell is equipped with the through hole, precombustion chamber shell is equipped with the precombustion chamber. The pre-combustion chamber shell is suitable for being placed in a combustion chamber of an engine, and when ignition is conducted in the pre-combustion cavity, sparks or flames are sprayed to the combustion chamber along the through holes. The thickness of the side wall of the precombustion chamber shell is larger than that of the bottom wall, the bottom wall is thin, the compactness of the structure can be guaranteed, the size of the precombustion chamber shell extending into a combustion chamber is reduced, fresh air enters the combustion chamber to form a higher turbulence ratio and turbulence energy, the combustion speed is increased, the thickness of the side wall is set to be larger, and the combustion efficiency is improved. And the strength of the pre-combustion chamber structure can be ensured.

Description

Technical Field

[0001] This utility model relates to the field of vehicle technology, and in particular to a pre-combustion chamber structure and engine. Background Technology

[0002] A pre-combustion chamber is an ignition mechanism used in internal combustion engines. It enables a more efficient and stable combustion process, effectively reducing emissions and improving engine thermal efficiency. It is suitable for various fuels, such as ammonia, hydrogen, and gasoline.

[0003] Because the gas mixture inside the pre-combustion chamber burns, there is a continuous high-temperature environment inside the pre-combustion chamber. When igniting inside the pre-combustion chamber, there is room for improvement in the structural strength and combustion speed of the pre-combustion chamber in the existing technology. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a pre-combustion chamber structure, wherein the sidewalls of the pre-combustion chamber shell are thicker than the bottom wall. The thinner bottom wall ensures the compactness of the structure and reduces the size of the pre-combustion chamber shell extending into the combustion chamber, allowing fresh air to enter the combustion chamber and form a stronger turbulence ratio and turbulent kinetic energy, thereby accelerating the combustion speed. The thicker sidewalls ensure the strength of the pre-combustion chamber structure.

[0005] According to the pre-combustion chamber structure of this utility model embodiment, the pre-combustion chamber shell defines a pre-combustion cavity. The pre-combustion chamber shell includes a side wall and a bottom wall. The thickness of the side wall is greater than the thickness of the bottom wall. The pre-combustion chamber shell is provided with a through hole. The pre-combustion chamber shell is suitable for being placed in the combustion chamber of an engine. When ignition occurs in the pre-combustion cavity, a spark or flame is sprayed into the combustion chamber along the through hole.

[0006] According to the pre-combustion chamber structure of this utility model embodiment, the side wall of the pre-combustion chamber shell is thicker than the bottom wall. The thin bottom wall can ensure the compactness of the structure and reduce the size of the pre-combustion chamber shell extending into the combustion chamber, so that fresh air enters the combustion chamber to form a stronger turbulence ratio and turbulent kinetic energy, thereby accelerating the combustion speed. Moreover, the side wall is set to be thicker, which can ensure the strength of the pre-combustion chamber structure.

[0007] According to the pre-combustion chamber structure of this utility model embodiment, the thickness of the bottom wall is a, and the thickness of the side wall is b, wherein 0.7≤a / b≤1.

[0008] According to the pre-combustion chamber structure of this utility model embodiment, a transition connection is formed between the side wall and the bottom wall, the through hole is provided at the transition connection, and the thickness of the transition connection is greater than the thickness of the side wall or the bottom wall.

[0009] According to the pre-combustion chamber structure of this utility model embodiment, the bottom wall is horizontally arranged, the extension line of the bottom wall is perpendicular to the extension line of the side wall, and the transition connection is an arc-shaped transition.

[0010] According to the pre-combustion chamber structure of this utility model embodiment, the through holes are provided in a plurality of manner, and the plurality of through holes are distributed at intervals along the lower circumferential direction of the pre-combustion chamber shell, the spacing between adjacent through holes is c, and satisfies 1mm≤c≤3mm.

[0011] According to the pre-combustion chamber structure of this utility model embodiment, both the side wall and the bottom wall include an inner wall and an outer wall connected along the inside and outside, and the thermal conductivity of the outer wall is higher than that of the inner wall.

[0012] According to the pre-combustion chamber structure of this utility model embodiment, the ratio of the thermal expansion coefficient of the inner wall material to the thermal expansion coefficient of the outer wall material is d, and satisfies 0.7≤d≤1.3.

[0013] According to the pre-combustion chamber structure of this utility model embodiment, the inner wall or the outer wall accounts for 1 / 3 to 2 / 3 of the thickness of the pre-combustion chamber shell.

[0014] According to the pre-combustion chamber structure of this utility model embodiment, the pre-combustion chamber can be configured such that the inner diameter of the end away from the bottom wall is larger than the inner diameter of the end close to the bottom wall.

[0015] This utility model embodiment also discloses an engine, including a spark plug and the above-described pre-combustion chamber structure, wherein at least a portion of the spark plug extends into the pre-combustion chamber cavity for ignition within the pre-combustion chamber, so that a spark is sprayed along the through hole into the combustion chamber.

[0016] The advantages of the engine described above compared to existing technologies are the same as those of the pre-combustion chamber structure described above compared to existing technologies, and will not be elaborated here.

[0017] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0019] Figure 1 This is a schematic diagram of the active pre-combustion chamber structure according to an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the pre-combustion chamber shell according to an embodiment of the present invention;

[0021] Figure 3 This is a schematic diagram of the passive pre-combustion chamber structure according to an embodiment of the present invention.

[0022] Figure label:

[0023] Pre-combustion chamber structure 100,

[0024] The pre-combustion chamber shell 1, outer wall 11, inner wall 12, through hole 13, side wall 14, inner side wall 141, outer side wall 142, transition connection 15, bottom wall 16, inner bottom wall 161, outer bottom wall 162, pre-combustion chamber 17, spark plug 2, fuel injector 3, center electrode 4, and side electrode 5. Detailed Implementation

[0025] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0026] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0028] The following is for reference. Figures 1-3The pre-combustion chamber structure 100 according to an embodiment of the present invention is described. The thickness of the side wall 14 of the pre-combustion chamber shell 1 is greater than the thickness of the bottom wall 16. The thinner bottom wall 16 ensures the compactness of the structure and reduces the size of the pre-combustion chamber extending into the combustion chamber, allowing fresh air to enter the combustion chamber and form a stronger turbulence ratio and turbulent kinetic energy, thus accelerating the combustion speed. The thicker side wall 14 ensures the strength of the pre-combustion chamber structure 100. Moreover, the pre-combustion chamber shell 1 includes an inner wall 12 and an outer wall 11 connected along the inside and outside. The thermal conductivity of the outer wall 11 is higher than that of the inner wall 12. Through the double-layer structure and the design of different thermal conductivity, the loss of ignition heat from the pre-combustion cavity 17 of the pre-combustion chamber shell 1 is reduced, while the ignition efficiency is improved. It also allows the heat of the pre-combustion chamber shell 1 to be rapidly dissipated from the outside of the pre-combustion chamber shell 1 and inside the combustion chamber, improving the phenomena of combustion chamber knock and pre-ignition.

[0029] like Figure 1-3 As shown, a pre-combustion chamber structure 100 according to an embodiment of the present invention includes: a pre-combustion chamber shell 1.

[0030] The pre-combustion chamber shell 1 defines the pre-combustion chamber 17. The pre-combustion chamber shell 1 includes a side wall 14 and a bottom wall 16. The thickness of the side wall 14 is greater than the thickness of the bottom wall 16. The pre-combustion chamber shell 1 is provided with a through hole 13. The pre-combustion chamber shell 1 is suitable for being placed in the combustion chamber of the engine. When ignition occurs in the pre-combustion chamber 17, the spark or flame is sprayed into the combustion chamber along the through hole 13.

[0031] In practice, it should be noted that this pre-combustion chamber structure is mainly used in two scenarios: passive and active. For example... Figure 1 As shown, in a passive application scenario, a spark plug 2 is provided on the upper part of the pre-combustion chamber housing 1. The working principle is to use the conventional spark plug 2 to ignite the mixture in the pre-combustion chamber housing 1. After combustion, it is injected into the combustion chamber through the through hole 13 of the pre-combustion chamber housing 1, forming multiple jet flames, which ignite the mixture in the combustion chamber of the engine, thereby accelerating the combustion speed, improving combustion stability, increasing combustion efficiency, and improving thermal efficiency.

[0032] like Figure 3 As shown, in the active application scenario, the upper part of the pre-combustion chamber housing 1 is equipped with an injector 3 and a spark plug 2. Based on the aforementioned passive application, the injector 3 is added. During the compression stroke, the injector 3 is used to introduce a small amount of fuel or a mixture of fuel and air into the pre-combustion chamber 17, which is ignited by the conventional spark plug 2. After the mixture in the pre-combustion chamber 17 is burned, it is injected into the combustion chamber through the through hole 13 of the pre-combustion chamber housing 1, forming multiple jet flames, which ignite the mixture in the engine combustion chamber, thereby achieving stable combustion under high dilution or high EGR rate, and thus improving the engine thermal efficiency. Here, high EGR rate refers to the high proportion of exhaust gas recirculation to total intake air in the exhaust gas recirculation system.

[0033] In active combustion applications, the ignition process can be actively controlled. This design results in higher ignition energy and faster flame propagation, making it suitable for high-dilution combustion and improving combustion speed while suppressing knocking. In passive combustion, oil and gas are drawn into the pre-combustion chamber 17 of the pre-combustion chamber shell 1 by negative pressure and ignited. This design makes the combustion process more natural and is suitable for traditional combustion needs.

[0034] Specifically, the pre-combustion chamber shell 1 of this utility model embodiment can be applied to both active and passive scenarios. When the thickness of the side wall 14 of the pre-combustion chamber shell 1 is greater than that of the bottom wall 16, the thin bottom wall 16 can ensure the compactness of the structure and reduce the size of the pre-combustion chamber shell 1 extending into the combustion chamber, allowing fresh air to enter the combustion chamber and form a stronger turbulence ratio and turbulent kinetic energy, thus accelerating the combustion speed. Moreover, the thickness of the side wall 14 is set to be relatively thick, so that the strength of the entire pre-combustion chamber shell 1 is not too low, thus ensuring the structural strength of the pre-combustion chamber shell 1.

[0035] In addition, it should be noted that the pre-combustion chamber housing 1 is located in the combustion chamber of the engine, and the top of the pre-combustion chamber housing 1 is also sealed by the cylinder head of the engine. This also limits the tensile strength of the overall material of the pre-combustion chamber housing 1 to 440 MPa-680 MPa and the yield strength to 250 MPa-680 MPa. Limiting the tensile strength and yield strength of the pre-combustion chamber housing 1 can ensure that under extreme conditions, the pre-combustion chamber housing 1 will not break due to excessive tensile force, thereby improving structural strength and extending the service life of the pre-combustion chamber housing 1.

[0036] In some embodiments, the thickness of the bottom wall 16 is a, and the thickness of the side wall 14 is b, wherein 0.7 ≤ a / b ≤ 1.

[0037] In practice, the thickness of the bottom wall can be set to 0.7 times, 0.8 times, or 0.9 times the thickness of the side wall, which means that the thickness of the bottom wall 16 can be less than the thickness of the side wall 14, while also reducing the thickness difference between the bottom wall 16 and the side wall 14, so that the difference in heating or strength is not too large. Thus, the strength of the pre-combustion chamber structure is guaranteed while reducing the thickness of the bottom wall 16.

[0038] In some embodiments, a transition connection 15 is formed between the sidewall 14 and the bottom wall 16, a through hole 13 is provided at the transition connection 15, and the thickness of the transition connection 15 is greater than the thickness of the sidewall 14 or the bottom wall 16.

[0039] In practice, such as Figure 3 As shown, the sidewall 14 includes an inner sidewall 141 and an outer sidewall 142, while the bottom wall 16 includes an inner bottom wall 161 and an outer bottom wall 162. The connection between the inner sidewall 141 and the inner bottom wall 161 and the connection between the outer sidewall 142 and the outer bottom wall 162 together form a transition connection 15.

[0040] By placing the through hole 13 at the transition connection 15 between the side wall 14 and the bottom wall 16, the spark or high-temperature flame can diffuse downwards when it is injected from the upper part of the pre-combustion chamber 17. By positioning the through hole 13 at the transition connection 15 between the side wall 14 and the bottom wall 16, while the mixture is ignited in the pre-combustion chamber 17 to generate a spark or flame, the spark or flame will converge toward the transition connection 15 near the side wall 14 and the bottom wall 16. Placing the through hole 13 at this position can improve the efficiency of spark injection, thereby improving the combustion efficiency of the mixture in the combustion chamber.

[0041] Furthermore, the thickness of the transition connection 15 is set to be thicker than that of the side wall 14 or the bottom wall 16, so that when the spark or high-temperature flame is ejected along the through hole 13, it is ejected along the thicker part. Since the temperature near the through hole 13 of the pre-combustion chamber shell 1 is high, increasing the thickness near the through hole 13 locally can enhance the reliability of the overall structure and improve the service life of the pre-combustion chamber shell 1.

[0042] The shape of the through hole 13 can be set as circular, elliptical, square, rectangular, etc., which can be determined according to the actual processing convenience and the range of sparks and flames sprayed from the pre-combustion chamber 17 into the combustion chamber.

[0043] In some embodiments, the bottom wall 16 is configured to be horizontal, the extension line of the bottom wall 16 is perpendicular to the extension line of the side wall 14, and the transition connection 15 is configured to be an arc transition.

[0044] like Figure 3 As shown, the extension lines of the bottom wall 16 and the side wall 14 are perpendicular to each other. The transition connection 15 between the bottom wall 16 and the side wall 14 is set as an arc transition. The arc transition can reduce the phenomenon of uneven heat at the transition connection 15 between the bottom wall 16 and the side wall 14, which can lead to local high temperature at the transition connection 15 and cause problems such as cracking of the pre-combustion chamber shell 1. When the bottom wall 16 is set to a horizontal direction, the spark and flame generate an interaction force with the bottom wall 16 when they reach the bottom wall 16. After the bottom wall 16 exerts a reverse force on the spark and flame, it can guide the spark and flame to a position of the bottom wall 16 near the side wall 14, such as to the transition connection 15 between the bottom wall 16 and the side wall 14, so as to achieve better and more efficient realization of the spark and flame being sprayed from the through hole 13 into the combustion chamber of the engine.

[0045] Of course, in actual design, the bottom wall 16 can also be set as an arched structure. The arched structure is set closer to the spark plug 2 along the direction from the transition connection 15 to the central axis of the pre-combustion chamber shell 1. That is, when the spark and flame are injected into the pre-combustion chamber 17 of the combustion chamber shell, the spark and flame come into contact with the inner bottom wall 161, and the spark and flame are guided to the transition connection 15 through the bottom wall 16 of the arched structure, thereby improving the ejection efficiency of the spark and flame.

[0046] In some embodiments, a plurality of through holes 13 are provided, and the plurality of through holes 13 are distributed at circumferential intervals along the transition connection 15, the spacing between adjacent through holes 13 is c, and satisfies 1mm≤c≤3mm.

[0047] The pre-combustion chamber shell 1 has multiple through holes 13 spaced circumferentially at its lower part. When the pre-combustion chamber shell 1 is located within the engine's combustion chamber, sparks and flames can be ejected along the bottom of the pre-combustion chamber shell 1 in multiple circumferential directions within the pre-combustion cavity 17. The through holes 13 are evenly distributed; the number of through holes 13 can be controlled to approximately 6-10, resulting in simultaneous combustion at multiple points within the combustion chamber. This improves the combustion speed and temperature of combustible gases, leading to high thermal efficiency and reduced harmful pollutant generation. Furthermore, the distance between adjacent through holes 13 is at least 1 mm, such as 2 mm or 3 mm, thereby enhancing the reliability of the pre-combustion chamber shell 1 and preventing the strength of the pre-combustion chamber shell 1 from being affected by excessively small distances between the through holes 13.

[0048] In some embodiments, the pre-combustion chamber shell 1 includes an inner wall 12 and an outer wall 11 connected along the inside and outside, wherein the thermal conductivity of the outer wall 11 is higher than that of the inner wall 12.

[0049] Specifically, the sidewall 14 includes an inner sidewall 141 and an outer sidewall 142, and the bottom wall 16 also includes an inner bottom wall 161 and an outer bottom wall 162. The outer wall 11 and the inner wall 12 of the pre-combustion chamber shell 1 are made of different materials. The inner wall 12 includes a connected inner sidewall 141 and an inner bottom wall 161, and the outer wall 11 includes a connected outer sidewall 142 and an outer bottom wall 162. The thermal conductivity of the material used for the inner wall 12 can be lower than that of the material used for the outer wall 11. Therefore, the inner sidewall 141 and... The thermal conductivity of the inner bottom wall 161 is set lower than that of the outer wall 142 and the outer bottom wall 162. For example, the inner wall 12 can be made of alloy steel, the outer wall 11 is made of copper alloy, and the thermal conductivity of the inner wall 12 is low. When the mixture in the pre-combustion chamber housing 1 is ignited, the energy released by combustion can be effectively prevented from being lost through the cylinder head and coolant, so that the energy in the pre-combustion chamber housing 1 can be fully transferred to the combustion chamber of the engine through the through hole 13, thereby improving the ignition capability of the mixture in the combustion chamber of the engine.

[0050] Furthermore, the outer wall 11 has a high thermal conductivity, which allows the heat from the contact surface between the outer wall 11 and the combustion chamber to be quickly dissipated through the cylinder head and coolant, thereby improving the phenomena of combustion chamber knock and pre-ignition. In other words, through the double-layer structure and the design of different thermal conductivity, the loss of ignition heat from the pre-combustion chamber 17 of the pre-combustion chamber shell 1 is reduced, while the ignition efficiency is improved. It also allows the heat of the pre-combustion chamber shell 1 to be quickly dissipated from the outside of the pre-combustion chamber shell 1 and inside the combustion chamber, thus improving the phenomena of combustion chamber knock and pre-ignition.

[0051] Pre-ignition refers to the phenomenon where the air-fuel mixture is ignited prematurely by a heat source during the compression stroke before the spark plug 2 has ignited. This leads to reduced power, unstable engine operation, and knocking noises and overheating. In other words, if the outer wall 11 has poor thermal conductivity, heat cannot be effectively dissipated, causing the pre-combustion chamber shell 1 to overheat, potentially resulting in pre-ignition. Knocking occurs after the spark plug 2 ignites, due to a sudden increase in pressure causing spontaneous combustion. This occurs when the heat from the outer wall 11 cannot dissipate, leading to excessively high temperatures and internal pressures in the entire pre-combustion chamber shell 1. Knocking typically occurs during the power stroke and causes high-frequency noise and knocking. Therefore, improving the heat dissipation effect of the outer wall 11 can reduce knocking.

[0052] Furthermore, the outer wall 11 is made of a material with a thermal conductivity of 150 W / mk-300 W / mk, while the inner wall 12 is made of a material with a thermal conductivity of 5-20 W / mk. This means that the thermal conductivity of the outer wall 11 is at least 10 times that of the inner wall 12. By defining the specific parameters of the inner and outer walls 11, suitable materials can be more easily selected. Moreover, by limiting the thermal conductivity of the inner wall 12 of the pre-combustion chamber shell 1, when the air-fuel mixture inside the pre-combustion chamber shell 1 is ignited, the energy released by combustion can be effectively prevented from dissipating through the cylinder head and coolant. This allows the energy inside the pre-combustion chamber shell 1 to be efficiently transferred to the combustion chamber through the through-hole 13, thereby enhancing the ignition capability of the air-fuel mixture in the combustion chamber through the pre-combustion chamber structure 100.

[0053] When the coefficient of thermal expansion of the outer wall 11 of the pre-combustion chamber shell 1 is limited, the heat of the contact surface between the pre-combustion chamber shell 1 and the combustion chamber can be quickly dissipated through the cylinder head and coolant, minimizing the temperature of the contact surface between the pre-combustion chamber shell 1 and the combustion chamber, thereby improving combustion chamber knock and pre-ignition. With this double-layer structure and the material selection of the inner wall 12 and the outer wall 11, the low temperature of the contact surface between the outer surface of the pre-combustion chamber shell 1 and the combustion chamber is achieved, improving knock or pre-ignition, while also reducing the heat transfer loss of the pre-combustion chamber shell 1, thereby improving engine thermal efficiency and maximizing the effect of the pre-combustion chamber shell 1 and the pre-combustion chamber 17.

[0054] It should also be noted that the spark plug 2 includes a center electrode 4 and a side electrode 5. When the ignition coil applies voltage to the center electrode 4, an electric spark is generated between the center electrode 4 and the side electrode 5, thereby igniting in the pre-combustion chamber 17 of the pre-combustion chamber housing 1. Since the combustion chamber is large, the spark or flame sprayed into the combustion chamber through the pre-combustion chamber housing 1 can ignite more of the mixture in the combustion chamber, thereby improving the ignition efficiency of the mixture in the combustion chamber.

[0055] In some embodiments, the ratio of the coefficient of thermal expansion of the material of the inner wall 12 to the coefficient of thermal expansion of the material of the outer wall 11 is d, and satisfies 0.7≤d≤1.3.

[0056] In practice, the inner wall 12 can be made of alloy steel. The advantages of alloy steel mainly include higher comprehensive mechanical properties such as strength, toughness, and wear resistance, as well as better hardenability, good corrosion resistance and high-temperature stability, fatigue resistance, and brittleness resistance. When the spark plug 2 ignites in the pre-combustion chamber 17, the spark or flame can directly contact the inner wall 12, meeting the requirements for spark plug 2 to ignite in the pre-combustion chamber 17. In addition, the outer wall 11 is made of copper alloy. Copper alloy has good corrosion resistance and can resist the erosion of various chemicals, making it suitable for various harsh environments. Furthermore, copper alloy has high strength and can withstand greater external forces. Copper alloy has excellent electrical and thermal conductivity, which also meets the requirements for the outer wall 11 to contact the gas in the combustion chamber. The heat of the contact surface between the pre-combustion chamber shell 1 and the combustion chamber can be quickly dissipated through the cylinder head and coolant, thereby effectively reducing the temperature of the contact surface between the pre-combustion chamber shell 1 and the combustion chamber, and thus improving the problems of combustion chamber knock and pre-ignition.

[0057] Specifically, a range is set for the ratio of the thermal expansion coefficient of the inner wall 12 material to that of the outer wall 11 material. If this ratio exceeds this range, meaning the thermal expansion coefficients of the inner wall 12 and outer wall 11 deviate significantly, the thicknesses of the inner wall 12 and outer wall 11 will exhibit inconsistent trends with temperature changes during engine combustion. Conversely, when the ratios of the inner wall 12 and outer wall 11 fall within this range, meaning their thermal expansion coefficients are relatively close, the dimensions of the inner wall 12 and outer wall 11 maintain consistent changes with temperature, thereby ensuring the reliability of the double-layer structure of the pre-combustion chamber shell 1.

[0058] Specifically, if the coefficient of thermal expansion of the inner wall 12 of the pre-combustion chamber is greater than that of the outer wall 11 of the pre-combustion chamber and the difference is greater than 30%, the inner wall 12 of the pre-combustion chamber will exert a large force on the outer wall 11 of the pre-combustion chamber. Under this force, the outer wall material of the pre-combustion chamber is at risk of cracking. If the coefficient of thermal expansion of the inner wall 12 of the pre-combustion chamber is lower than that of the outer wall 11 of the pre-combustion chamber and the difference is greater than 30%, there will be a significant gap between the inner wall 12 and the outer wall 11 of the pre-combustion chamber shell 1. If this gap is too large, it will cause cracking between the inner wall 12 and the outer wall 11, thereby affecting the reliability of the engine. Therefore, the deviation of the coefficients of thermal expansion of the inner wall 12 and the outer wall 11 is set within ±30% to avoid this problem.

[0059] Among them, the coefficient of thermal expansion of the inner wall 12 material can be between 1.2×10^-5 / ℃ and 1.8×10^-5 / ℃, and the coefficient of thermal expansion of the outer wall 11 material can be between 1.5×10^-5 / ℃ and 2.0×10^-5 / ℃. It is necessary to keep the coefficient of thermal expansion of the inner wall 12 material and the coefficient of thermal expansion of the outer wall 11 within the above-mentioned difference range.

[0060] In some embodiments, the inner wall 12 or the outer wall 11 accounts for 1 / 3 to 2 / 3 of the thickness of the pre-combustion chamber shell 1.

[0061] For example, the inner wall 12 can be set to account for 1 / 3 of the thickness of the pre-combustion chamber shell 1, and the outer wall 11 can be set to account for 2 / 3 of the thickness of the pre-combustion chamber shell 1. Alternatively, the inner wall 12 can be set to account for 2 / 3 of the thickness of the pre-combustion chamber shell 1, and the outer wall 11 can be set to account for 1 / 3 of the thickness of the pre-combustion chamber shell 1. Of course, the inner wall 12 can also be set within the range of 1 / 3 to 2 / 3 of the thickness of the pre-combustion chamber shell 1, or the outer wall 11 can be set within the range of 1 / 3 to 2 / 3 of the thickness of the pre-combustion chamber shell 1. This avoids an excessive difference in wall thickness between the inner wall 12 and the outer wall 11, and prevents the inner wall 12 or the outer wall 11 from being set too thin. This makes the effects of the materials selected for the inner wall 12 or the outer wall 11 more balanced, that is, balancing the problems of knocking and pre-ignition in the combustion chamber with the problem of improving ignition efficiency.

[0062] Furthermore, the inner wall 12 and the outer wall 11 are welded together by brazing. In the brazing process, only the filler metal melts, while the heating temperature of the base material is relatively low. Therefore, the deformation of the weldment is small. In particular, when the integral heating method is used, the deformation of the weldment can be minimized, thereby ensuring the dimensional accuracy of the weldment. In other words, the impact of welding on the inner wall 12 and the outer wall 11 can be minimized, thereby improving the shape accuracy of the inner wall 12 and the outer wall 11. Moreover, the brazing method can also maintain the integrity of the connection between the inner wall 12 and the outer wall 11.

[0063] In addition, the top of the pre-combustion chamber housing 1 is also sealed by the cylinder head, meaning that the engine cylinder head can cover both the combustion chamber and the top of the pre-combustion chamber housing 1, thereby ensuring the sealing of the spark plug 2 and the fuel injector 3.

[0064] In some embodiments, the pre-combustion chamber 17 may be configured such that the inner diameter of the end away from the bottom wall 16 is larger than the inner diameter of the end near the bottom wall 16.

[0065] If can Figure 1-3 The shape of the pre-combustion chamber housing 1 can be designed such that the inner diameter of the side closer to the spark plug 2 is larger than the inner diameter of the side farther away from the spark plug 2. That is, when ignition occurs between the center electrode 4 and the side electrode 5 of the spark plug 2, the spark and flame can be concentrated and flow toward the through hole 13 at the bottom of the pre-combustion chamber 17. This allows the spark and flame to be ejected more quickly along the circumferential through hole 13 at the bottom of the pre-combustion chamber housing 1, thereby improving the ignition efficiency of the air-fuel mixture in the combustion chamber of the engine.

[0066] Of course, the pre-combustion chamber shell 1 can also be divided into a first section, a second section and a third section formed integrally from bottom to top. That is, the pre-combustion chamber 17 includes the space enclosed by the first section, the second section and the third section connected sequentially from bottom to top. The first section is perpendicular to the bottom wall 16, the angle between the second section and the first section is an obtuse angle, the third section is also perpendicular to the bottom wall 16, and the head of the spark plug 2 is located in the space formed by the third section. The head of the spark plug 2 is the end of the center electrode 4 and the side electrode 5 that can generate a spark under the action of voltage. In this way, after the flame and spark are ignited in the space formed by the third section, the flame and spark can be guided along the second section and flow into the space formed by the first section, which increases the speed of the flame flow to the through hole 13 and improves the ignition efficiency of the mixture in the combustion chamber.

[0067] Additionally, it should be noted that in this embodiment of the present invention, a plug hole corresponding to the spark plug 2 can be provided at the cylinder head. The position where the spark plug 2 connects to the cylinder head is provided with an external thread, and the plug hole is provided with an internal thread corresponding to the external thread of the spark plug 2. The spark plug 2 is connected to the spark plug 2 through the plug hole and sealed. This makes it convenient to install the spark plug 2 and ensures that the mixture in the pre-combustion chamber 17 will not leak to the top of the pre-combustion chamber shell 1. Moreover, the horizontal distance between the spark plug 2 and the inner wall 12 is at least greater than 4 times the sum of the thicknesses of the inner wall 12 and the outer wall 11. That is, under the premise that the wall thickness of the pre-combustion chamber shell 1 meets the working requirements, the spark plug 2 is kept too close to the inner wall 12, which would cause continuous high temperature effects on the inner wall 12 and the outer wall 11, resulting in thermal deformation of the inner wall 12 and the outer wall 11.

[0068] Figure 3In this configuration, the fuel injector 3 is tilted and forms an angle with the spark plug 2. For example, the head of the spark plug 2 extends vertically into the pre-combustion chamber 17 formed by the pre-combustion chamber housing 1. The angle between the central axis of the fuel injector 3 and the central axis of the spark plug 2 can be set between 10° and 45°, such as 10°, 20°, 25°, 30°, etc. If the angle is set too small, it may be difficult for the fuel gas to be sprayed towards the position near the central electrode 4 and the side electrode 5, resulting in an excessively lean fuel gas concentration at the spark plug 2, uneven fuel gas distribution, and poor ignition assist effect, thus leading to poor ignition effect in the combustion chamber. If the angle is set too large, the fuel gas may be sprayed towards the cylinder head. Therefore, setting the angle between the central axis of the fuel injector 3 and the central axis of the spark plug 2 within the above range can achieve uniform fuel gas distribution and enable the fuel injector 3 to effectively assist the ignition process.

[0069] This utility model embodiment also discloses an engine, including a spark plug and a pre-combustion chamber structure 100 as described in any of the above embodiments. At least a portion of the spark plug 2 extends into the pre-combustion chamber 17 for ignition within the pre-combustion chamber 17, so that the spark is sprayed into the combustion chamber along the through hole 13. The side wall 14 of the pre-combustion chamber shell 1 is thicker than the bottom wall 16. The thin bottom wall 16 ensures the compactness of the structure and reduces the size of the pre-combustion chamber shell 1 extending into the combustion chamber, allowing fresh air to enter the combustion chamber and form a stronger turbulence ratio and turbulent kinetic energy, thereby accelerating the combustion speed. The thicker side wall 14 ensures the strength of the pre-combustion chamber structure 100, improves the combustion speed of the engine, and extends the service life of the combustion chamber structure 100.

[0070] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0071] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A pre-combustion chamber structure, characterized in that, include: A pre-combustion chamber housing defines a pre-combustion chamber. The pre-combustion chamber housing includes a side wall and a bottom wall. The thickness of the side wall is greater than the thickness of the bottom wall. The pre-combustion chamber housing is provided with a through hole. The pre-combustion chamber housing is adapted to be placed in the combustion chamber of an engine. When ignition occurs in the pre-combustion chamber, a spark or flame is sprayed into the combustion chamber along the through hole.

2. The pre-combustion chamber structure according to claim 1, characterized in that, The thickness of the bottom wall is a, and the thickness of the side wall is b, wherein 0.7 ≤ a / b ≤ 1.

3. The pre-combustion chamber structure according to claim 1, characterized in that, A transition connection is formed between the sidewall and the bottom wall, the through hole is provided at the transition connection, and the thickness of the transition connection is greater than the thickness of the sidewall or the bottom wall.

4. The pre-combustion chamber structure according to claim 3, characterized in that, The bottom wall is horizontally oriented, the extension line of the bottom wall is perpendicular to the extension line of the side wall, and the transition connection is an arc-shaped transition.

5. The pre-combustion chamber structure according to claim 3, characterized in that, The through holes are configured as a plurality of holes, and the plurality of through holes are distributed circumferentially at intervals along the transition connection. The spacing between adjacent through holes is c, and satisfies 1mm≤c≤3mm.

6. The pre-combustion chamber structure according to claim 1, characterized in that, The pre-combustion chamber shell includes an inner wall and an outer wall connected along the inside and outside, wherein the thermal conductivity of the outer wall is higher than that of the inner wall.

7. The pre-combustion chamber structure according to claim 6, characterized in that, The ratio of the thermal expansion coefficient of the inner wall material to that of the outer wall material is d, and satisfies 0.7≤d≤1.

3.

8. The pre-combustion chamber structure according to claim 6, characterized in that, The inner wall or the outer wall occupies 1 / 3 to 2 / 3 of the thickness of the pre-combustion chamber shell.

9. The pre-combustion chamber structure according to claim 1, characterized in that, The pre-combustion chamber can be configured such that the inner diameter of the end furthest from the bottom wall is larger than the inner diameter of the end closest to the bottom wall.

10. An engine, characterized in that, The invention includes a spark plug and a pre-combustion chamber structure as described in any one of claims 1-9, wherein at least a portion of the spark plug extends into the pre-combustion chamber for ignition within the pre-combustion chamber, such that a spark is directed along the through-hole into the combustion chamber.

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