Precombustion chamber and engine

Abstract

The present invention provides a pre-combustion chamber and an engine, the pre-combustion chamber comprising a shell, a pre-combustion chamber is formed in the lower part of the shell, a plug-in hole connected to the pre-combustion chamber and suitable for inserting a spark plug is formed in the upper part of the shell, a flame-spraying hole connected to the pre-combustion chamber is also formed in the lower part of the shell, and the length H of the pre-combustion chamber in the vertical direction is greater than or equal to the diameter D of the plug-in hole, and less than or equal to 3 times the diameter D of the plug-in hole. The pre-combustion chamber of the present invention can effectively concentrate a relatively concentrated oil-gas mixture in a limited space by setting the length H of the pre-combustion chamber within a limited range, which is conducive to the electric spark generated by the spark plug electrode to quickly ignite the oil-gas mixture to form a higher energy flame flow. At the same time, the high energy flame flow can also enter the main combustion chamber through the flame-spraying hole in the shortest path, and quickly ignite the oil-gas mixture in the main combustion chamber, thereby improving the ignition effect of the engine.

Description

Technical Field

[0001] The present invention relates to the technical field of spark plugs, and in particular to a pre-combustion chamber. The present invention also relates to an engine. Background Art

[0002] At present, in the domestic and foreign automotive industries, high thermal efficiency and small displacement hybrid gasoline engines have attracted much attention. Gasoline engines rely on spark plugs to ignite the oil-gas mixture in the cylinder, and after full combustion, they output power and torque. Traditional gasoline engines use a spark plug mounting hole arranged on the upper part of the combustion chamber of the cylinder head. After the spark plug electrode generates an electric spark, it ignites the mixed oil and gas in the cylinder body. However, the current problem is that the ignition capacity of the spark plug is limited, which easily leads to incomplete combustion of the mixture.

[0003] The current high thermal efficiency engine often uses a new ignition device, which adds a new pre-combustion chamber or a pre-combustion chamber spark plug on the basis of the cylinder head combustion chamber. The existing gasoline engine combustion chamber mainly has several shapes: hemispherical combustion chamber, pentagonal combustion chamber, wedge-shaped combustion chamber, etc. The above combustion chambers are simple to process, low in production cost, and small in heating area. When working, the spark plug first ignites the oil and gas in the pre-combustion chamber to form a flame flow, which is ejected through the flame-spraying hole of the pre-combustion chamber, and then ignites the mixed gas in the main combustion chamber to increase the combustion speed.

[0004] The arrangement of the spark plug electrode and the flame jet hole in the existing pre-combustion chamber is unreasonable, and the flame flow in the pre-combustion chamber cannot be fully and effectively utilized, which will affect the ignition effect of the engine. In addition, the existing pre-combustion chamber arrangement has three main manifestations: First, the flame flow has not been fully formed, but it is sprayed to the main combustion chamber through the flame jet hole, and the flame energy is low; second, after the flame flow is fully formed, it has to flow in the pre-combustion chamber for a period of time before being sprayed to the main combustion chamber through the flame jet hole, and the utilization rate of the flame flow is low; third, the flame has not been transmitted, and the end mixture is natural, resulting in detonation, and a normal flame flow cannot be formed. Summary of the invention

[0005] In view of this, the present invention aims to provide a pre-combustion chamber to improve the ignition effect of the engine.

[0006] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A pre-combustion chamber comprises a shell, wherein a pre-combustion cavity is formed in the lower part of the shell, an insertion hole connected with the pre-combustion cavity and suitable for inserting a spark plug is formed in the upper part of the shell, and a flame-spraying hole connected with the pre-combustion cavity is also formed in the lower part of the shell, and a length H of the pre-combustion cavity in the vertical direction is greater than or equal to a diameter D of the insertion hole and less than or equal to 3 times the diameter D of the insertion hole.

[0008] Furthermore, the pre-combustion chamber includes a first chamber, a second chamber and a third chamber which are arranged in sequence from top to bottom; the second chamber is a variable diameter chamber which gradually decreases in diameter from the first chamber to the third chamber, the first chamber is an equal diameter chamber which has the same diameter as the large diameter end of the second chamber, and the third chamber has at least an equal diameter portion which has the same diameter as the small diameter end of the second chamber; the flame hole is arranged at the bottom of the third chamber.

[0009] Furthermore, the third chamber also has an arc-shaped cavity portion located at its bottom; the arc-shaped cavity portion is connected to the equal-diameter portion; and the flame-spraying hole is arranged on the inner wall of the arc-shaped cavity portion.

[0010] Furthermore, the height h1 of the first chamber satisfies: h1≤35%H; the height h2 of the second chamber satisfies: h1≤h2≤50%H; and the height h3 of the third chamber satisfies: 90%h1≤h3≤35%H.

[0011] Furthermore, the head of the inserted spark plug extends into the first chamber, and the ground electrode in the head extends into the second chamber.

[0012] Furthermore, a distance h0 between the ground electrode and an upper end portion of the second chamber, and a distance h4 between the ground electrode and an upper end portion of the first chamber, satisfy the following relationship: h0≤30%h4.

[0013] Furthermore, the distance h4 between the ground electrode and the upper end of the first chamber, the height H of the pre-combustion chamber, and the diameter D of the spark plug satisfy: 30%H≤h4≤40%H, and 50%D≤h4≤70%D.

[0014] Furthermore, the flame-spraying holes include a plurality of first flame-spraying holes and a plurality of second flame-spraying holes, and the connecting openings between the second flame-spraying holes and the arc-shaped cavity portion are lower than the connecting openings between the first flame-spraying holes and the arc-shaped cavity portion;

[0015] The distance h5 between the first flame hole and the connecting opening of the arc-shaped cavity part and the ground electrode satisfies: 50%H≤h5≤60%H; the distance h6 between the second flame hole and the connecting opening of the arc-shaped cavity part and the ground electrode, and the height H of the pre-combustion cavity, satisfy: h6≤70%H.

[0016] Furthermore, the number of the flame holes is between 4 and 8, and the diameter of the flame holes is between 0.8 and 2 mm.

[0017] Compared with the prior art, the present invention has the following advantages:

[0018] The pre-combustion chamber described in the present invention can effectively concentrate a relatively concentrated oil-gas mixture in a limited space by setting the length H of the pre-combustion chamber within a limited range, which is conducive to the electric spark generated by the spark plug electrode to quickly ignite the oil-gas mixture to form a higher energy flame flow. At the same time, the high energy flame flow can also enter the main combustion chamber through the flame hole in the shortest path, quickly ignite the oil-gas mixture in the main combustion chamber, thereby improving the ignition effect of the engine.

[0019] Another object of the present invention is to provide an engine having a pre-combustion chamber as described above, and the housing is integrated in the cylinder head of the engine; or, the housing is integrated on the spark plug.

[0020] The engine described in the present invention, by assembling the above pre-combustion chamber, can quickly ignite the mixed gas to form a flame flow with higher energy, so as to introduce the oil-gas mixed gas into the main combustion chamber of the cylinder, thereby forming a better ignition effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0022] Figure 1 is a cross-sectional view of the pre-combustion chamber according to the first embodiment of the present invention;

[0023] Figure 2 It is a partial cross-sectional view of the pre-combustion chamber described in the first embodiment of the present invention.

[0024] Description of reference numerals:

[0025] 1. Shell; 101. First chamber; 102. Second chamber; 103. Third chamber; 1031. Equal diameter portion; 1032. Arc-shaped chamber portion; 10321. Flame-spraying hole; 103211. First flame-spraying hole; 103212. Second flame-spraying hole; 2. Spark plug; 201. Head; 2011. Ground electrode. DETAILED DESCRIPTION

[0026] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0027] In the description of the present invention, it should be noted that if there are terms indicating orientation or positional relationship such as "upper", "lower", "inner", "outer", etc., they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, if there are terms such as "first", "second", etc., they are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0028] In addition, in the description of the present invention, unless otherwise clearly defined, the terms "installed", "connected", "connection" and "connector" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in combination with specific circumstances.

[0029] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0030] Embodiment 1

[0031] The present embodiment relates to a pre-combustion chamber, which in terms of overall design comprises a shell 1, a pre-combustion chamber is formed in the lower portion of the shell 1, an insertion hole connected to the pre-combustion chamber and suitable for inserting the spark plug 2 is formed in the upper portion of the shell 1, and a flame injection hole 10321 connected to the pre-combustion chamber is also formed in the lower portion of the shell 1.

[0032] In addition, the length H of the pre-combustion chamber in the vertical direction of this embodiment is greater than or equal to the diameter D of the above-mentioned insertion hole, and the length H is also less than or equal to 3 times the diameter D of the insertion hole.

[0033] The pre-combustion chamber of this embodiment, by setting the length H of the pre-combustion chamber within the above-mentioned range, can effectively concentrate the relatively thick oil-gas mixture in the limited space within the pre-combustion chamber, which is beneficial for the electric spark generated by the electrode of the spark plug 2 to quickly ignite the oil-gas mixture to form a higher energy flame flow. At the same time, the high energy flame flow can also enter the main combustion chamber of the cylinder through the flame hole 10321 in the shortest path, and can quickly ignite the oil-gas mixture in the main combustion chamber, thereby improving the ignition effect of the engine.

[0034] Based on the above overall structure introduction, an exemplary structure of the pre-combustion chamber of this embodiment is as follows: Figure 1As shown in , at this time, as a preferred embodiment, the pre-combustion chamber formed in the shell 1 includes a first chamber 101, a second chamber 102 and a third chamber 103 arranged in sequence from top to bottom, and the second chamber 102 is a variable diameter chamber that gradually decreases in diameter from the first chamber 101 to the third chamber 103, the first chamber 101 is an equal diameter cavity with the same diameter as the large diameter end of the second chamber 102, and the third chamber 103 has an equal diameter portion 1031 with the same diameter as the small diameter end of the second chamber 102.

[0035] As a further preferred implementation form, in this embodiment, the third chamber 103 further has an arc-shaped cavity portion 1032 located at its bottom. The arc-shaped cavity portion 1032 is connected to the equal-diameter portion 1031, so that the two together form the entire third chamber 103. At the same time, in this embodiment, the flame-spraying hole 10321 is provided at the bottom of the third chamber 103, specifically, on the inner wall of the arc-shaped cavity portion 1032.

[0036] In this embodiment, through the setting of the flame hole 10321, the fresh oil-gas mixture in the main combustion chamber of the cylinder, and specifically the fresh oil-gas mixture in the cylinder head combustion chamber, enters the pre-combustion cavity of the pre-combustion chamber through the flame hole 10321. Similarly, the flame flow in the pre-combustion chamber also flows to the cylinder head combustion chamber through the flame hole 10321, so that the main combustion chamber can be ignited after pre-combustion in the pre-combustion chamber.

[0037] In addition, in addition to further providing the arc-shaped cavity portion 1032 , it should be noted that, of course, the third chamber 103 can also be composed of only the equal-diameter portion 1031 . In this case, the above-mentioned flame holes 10321 can also be directly formed at the bottom of the third chamber 103 .

[0038] In this embodiment, the head 201 of the spark plug 2 inserted through the insertion hole extends into the first chamber 101, and the ground electrode 2011 in the head 201 also extends into the second chamber 102. In addition, in this embodiment, the number of the flame-spraying holes 10321 is also set between 4 and 8, and the specific number can be determined according to the displacement of the vehicle. In addition, the diameter of each flame-spraying hole 10321 is also set between 0.8 mm and 2 mm, and it should be pointed out that in the overall design of the flame-spraying holes 10321, the diameter of the flame-spraying holes 10321 is approximately inversely proportional to the number of the flame-spraying holes 10321.

[0039] Therefore, when the number of the flame holes 10321 is large, for example, 8, the diameter of the flame holes 10321 adopts a lower value, for example, 0.8 mm, and when the number of the flame holes 10321 is small, for example, 4, the diameter of the flame holes 10321 can be increased, and for example, 2 mm can be adopted to obtain a better ignition effect.

[0040] In addition, by limiting the diameter of the flame injection hole 10321 within the above range, the flame flow entering the main combustion chamber of the cylinder through the flame injection hole 10321 can effectively maintain its high energy, thereby ensuring the ignition effect. If the aperture of the flame injection hole 10321 is too small, the flame is easily extinguished, which will directly affect the combustion efficiency of the mixed gas in the main combustion chamber.

[0041] At the same time, through the above limitation on the number of the flame holes 10321, this embodiment can also achieve a balance between the flame coverage performance and the ignition performance, and thus can also ensure the ignition effect on the cylinder head combustion chamber. Moreover, if the number of the flame holes 10321 is too small, it is not conducive to the flame flow in the pre-combustion chamber to fully cover the entire cylinder head combustion chamber space, and it is not conducive to the uniform combustion of the mixture in the cylinder head combustion chamber. It is easy to cause the mixture at the end of the combustion chamber to spontaneously ignite, resulting in low combustion efficiency. If there are too many flame holes 10321, although the flame flow can effectively cover the combustion chamber space, in the limited pre-combustion chamber bottom space, the excessive number of flame holes 10321 means that the diameter of the flame hole 10321 is too small, and the flame flow is very likely to be extinguished when passing through, which is also not conducive to the ignition of the oil-gas mixture in the cylinder head combustion chamber.

[0042] Still combined Figure 1 As shown, in this embodiment, the plurality of flame holes 10321 include a plurality of first flame holes 103211 and a plurality of second flame holes 103212, and the connecting opening between the second flame holes 103212 and the arc-shaped cavity portion 1032 is lower than the connecting opening between the first flame holes 103211 and the arc-shaped cavity portion 1032. After the spark plug 2 in the pre-combustion chamber 1 is ignited by the ground electrode 2011, the formed flame flow will flow out through the flame holes 10321 and then ignite the mixed gas in the main combustion chamber. Therefore, by reasonably arranging the positions of the first flame holes 103211 and the second flame holes 103212, the ignition of the mixed gas can be made more uniform, and the occurrence of engine knocking can be improved, thereby improving the stability of the engine operation.

[0043] In this embodiment, refer to Figure 2 As shown, it should be noted that h0 is the distance of the ground electrode 2011 extending into the second chamber 102, h1 is the height of the first chamber 101, h2 is the height of the second chamber 102, h3 is the height of the third chamber 103, h4 is the distance between the ground electrode 2011 and the upper end of the first chamber 101, h5 is the distance between the first flame-spraying hole 103211 and the connecting port of the arc-shaped chamber part 1032 and the ground electrode 2011, and h6 is the distance between the second flame-spraying hole 103212 and the connecting port of the arc-shaped chamber part 1032 and the ground electrode 2011. H is also the overall height of the pre-combustion chamber, and D is the diameter of the insertion hole, that is, the diameter of the spark plug 2.

[0044] At this time, in order to improve the ignition effect of the grounding electrode 2011 of the spark plug 2, the distance h0 of the grounding electrode 2011 in this embodiment extending into the second chamber 102, and the distance h4 between the grounding electrode 2011 and the upper end of the first chamber 101, both satisfy: h0≤30%h4, thereby the mixture in the pre-combustion chamber 1 can be quickly ignited and the mixture can be fully burned.

[0045] At the same time, after the relative position between the ground electrode 2011 of the spark plug 2 and the second chamber 102 is determined, the center electrode position of the spark plug 2 is also determined, and it is also the initial spark center position of the spark plug 2. At this time, by making the ground electrode 2011 adopt the above-mentioned arrangement range, it can be ensured that the spark generated by the electrode of the spark plug 2 is effectively transmitted to the upper end of the first chamber 101, and then the oil-gas mixture at the upper end of the first chamber 101 can be effectively ignited, and driven by the air flow movement in the pre-combustion chamber, it flows to the bottom of the pre-combustion chamber. At the same time, the above-mentioned arrangement can also avoid the self-ignition of the high-temperature oil-gas mixture at the upper end of the first chamber 101 before the spark arrives due to the long spark transmission distance at the upper end of the first chamber 101, or even detonation.

[0046] The distance h4 between the ground electrode 2011 and the upper end of the first chamber 101, the height H of the pre-combustion chamber, and the diameter D of the spark plug 2 satisfy the following conditions: 30% H≤h4≤40% H, and 50% D≤h4≤70% D. By setting the matching relationship between the distance h4 between the ground electrode 2011 and the upper end of the first chamber 101 and the height H of the pre-combustion chamber, the ground electrode 2011 of the spark plug 2 can play a better role in the pre-combustion chamber 1 and can increase the ignition speed of the mixture. In addition, the setting of the matching relationship between the diameter D of the spark plug 2 and the distance h4 between the ground electrode 2011 and the upper end of the first chamber 101 can ensure the ignition effect of the ground electrode 2011.

[0047] In addition, in this embodiment, the height h1 of the first chamber 101 satisfies: h1≤35% H, the height h2 of the second chamber 102 satisfies: h1≤h2≤50% H, and the height h3 of the third chamber 103 satisfies: 90% h1≤h3≤35% H. By setting the ratio of the height h1 of the first chamber 101, the height h2 of the second chamber 102, and the height h3 of the third chamber 103 to the height H of the pre-combustion chamber, the distribution of the multiple chambers of the pre-combustion chamber can be rationalized, thereby ensuring the rapid ignition of the mixed gas and making the combustion more uniform, so as to improve the combustion effect of the main combustion chamber.

[0048] Limiting the height of the first chamber 101 within the above range can effectively concentrate the richer oil-gas mixture around the electrode of the spark plug 2. At the same time, the distances from the electric spark generated by the electrode of the spark plug 2 to the periphery and upper end of the first chamber 101 are approximately the same. As a result, the electric spark can be simultaneously transmitted to the periphery and upper end of the first chamber 101 to ignite the oil-gas mixture to form a high-energy flame flow, thereby preventing the electric spark from propagating at different distances and times, causing the surrounding mixture to spontaneously ignite and produce detonation.

[0049] At the same time, by limiting the height of the second chamber 102 within the above-mentioned range, the high-energy flame flow in the pre-combustion chamber can be effectively gathered at the upper part of the flame hole 10321, so that the flame flow can quickly and directly pass through the flame hole 10321 into the main combustion chamber, ignite the oil-gas mixture in the main combustion chamber, so as to form rapid and uniform combustion, thereby effectively improving the combustion efficiency of the mixture.

[0050] In this embodiment, the distance h5 between the first flame hole 103211 and the connecting port of the arc-shaped cavity portion 1032 and the ground electrode 2011, as well as the height H of the pre-combustion chamber, satisfy the following conditions: 50%H≤h5≤60%H; the distance h6 between the second flame hole 103212 and the connecting port of the arc-shaped cavity portion 1032 and the ground electrode 2011, as well as the height H of the pre-combustion chamber, satisfy the following conditions: h6≤70%H. The positions of the first flame hole 103211 and the second flame hole 103212 are arranged so that the spray distance of the flame ejected from the first flame hole 103211 and the second flame hole 103212 can be adjusted, so that the spray distances of the multiple first flame holes 103211 and the multiple second flame holes 103212 are as equal as possible, so that the ignition of the mixture can become more uniform.

[0051] It can be understood that after the ground electrode 2011 of the spark plug 2 is ignited, it can quickly ignite the oil-gas mixture in the pre-combustion chamber, and can quickly form a fire core, and then ignite the mixture in the pre-combustion chamber to form a high-energy flame flow. At this time, the high-energy flame flow can quickly pass through the flame hole 10321 into the main combustion chamber, which can reduce the energy loss in flame propagation, and can make the mixture burn fully, thereby improving the ignition effect.

[0052] Moreover, through the above-mentioned limitations on the distance h5 and the distance h6, and combined with the above-mentioned limitations on the range of the distance h4, this embodiment can effectively transmit the electric spark generated by the electrode of the spark plug 2 to the upper end of the first chamber 101 and the lower end of the second chamber 102, and can make the time and distance of the propagation of the electric spark or flame flow in the pre-combustion chamber located above the flame hole 10321 approximately the same, so that the oil-gas mixture in the pre-combustion chamber can be effectively ignited, avoiding the spontaneous combustion of the surrounding mixture and the generation of detonation due to the different propagation distances and times of the electric spark.

[0053] The pre-combustion chamber of the present embodiment adopts the above-mentioned overall setting. By arranging the relative positions of the ignition electrode of the spark plug 2 and the height of the flame hole 10321 and rationally designing the pre-combustion chamber structure of the pre-combustion chamber 1, a high-energy fire core can be quickly formed after the spark plug 2 is ignited. The high-energy flame flow then ignites the mixture in the main combustion chamber through the flame hole 10321. As a result, the high-energy flame flow in the pre-combustion chamber can ignite the mixture in the main combustion chamber through the flame hole 10321, which can make the mixture in the combustion chamber fully burn, thereby improving the economy and emission of the engine, and has good practicality.

[0054] At the same time, the pre-combustion chamber of the present embodiment makes the time and distance for the electric spark generated by the electrode of the spark plug 2 to propagate to the walls of various parts of the pre-combustion chamber approximately the same, and can also effectively ignite the oil-gas mixture in the pre-combustion chamber, thereby avoiding the spontaneous combustion of the surrounding mixture caused by different propagation distances and times of the electric spark, thereby also reducing the possibility of detonation.

[0055] Embodiment 2

[0056] This embodiment relates to an engine, which has the pre-combustion chamber described in the first embodiment, and the housing 1 is integrated in the cylinder head of the engine; or, the housing 1 is integrated on the spark plug. When the housing 1 is integrated on the spark plug 2, the spark plug 2 is also an integrated spark plug with a pre-combustion chamber, and the integration of the housing 1 on the spark plug 2 and the integrated arrangement of the housing 1 on the cylinder head can all be referred to the relevant structures in the prior art.

[0057] The engine of this embodiment, by providing the pre-combustion chamber described in the first embodiment, can quickly ignite the mixture in the pre-combustion chamber and form a flame flow with higher energy to enter the cylinder to form a better ignition effect. It can also reduce the possibility of knock in the combustion chamber, improve the stability of the engine operation, and has good practicality.

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A pre-combustion chamber, comprising a shell (1), wherein a pre-combustion chamber is formed in the lower part of the shell (1), an insertion hole communicating with the pre-combustion chamber and suitable for inserting a spark plug (2) is formed in the upper part of the shell (1), and a flame injection hole (10321) communicating with the pre-combustion chamber is also formed in the lower part of the shell (1), characterized in that: The length H of the pre-combustion chamber in the vertical direction is greater than or equal to the diameter D of the insertion hole, and less than or equal to 3 times the diameter D of the insertion hole; The pre-combustion chamber comprises a first chamber (101), a second chamber (102) and a third chamber (103) which are arranged in sequence from top to bottom; The second chamber (102) is a variable diameter chamber whose diameter gradually decreases from the first chamber (101) to the third chamber (103); the first chamber (101) is an equal diameter chamber whose diameter is equal to that of the large diameter end of the second chamber (102); and the third chamber (103) has at least an equal diameter portion (1031) whose diameter is equal to that of the small diameter end of the second chamber (102); The flame-spraying hole (10321) is arranged at the bottom of the third chamber (103), and the third chamber (103) further has an arc-shaped cavity portion (1032) located at the bottom thereof; The head (201) of the inserted spark plug (2) extends into the first chamber (101), and the ground electrode (2011) in the head (201) extends into the second chamber (102), the flame-spraying hole (10321) comprises a plurality of first flame-spraying holes (103211) and a plurality of second flame-spraying holes (103212), and the connecting opening between the second flame-spraying hole (103212) and the arc-shaped cavity portion (1032) is lower than the connecting opening between the first flame-spraying hole (103211) and the arc-shaped cavity portion (1032); A distance h5 between the first flame-spraying hole (103211), the communicating opening of the arc-shaped cavity portion (1032), and the grounding electrode (2011) satisfies: 50%H≤h5≤60%H.

2. The pre-combustion chamber according to claim 1, characterized in that: The arc-shaped cavity portion (1032) is connected to the equal-diameter portion (1031); The flame-spraying hole (10321) is arranged on the inner wall of the arc-shaped cavity portion (1032).

3. The pre-combustion chamber according to claim 1, characterized in that: The height h1 of the first chamber (101) satisfies: h1≤35%H; The height h2 of the second chamber (102) satisfies: h1≤h2≤50%H; The height h3 of the third chamber (103) satisfies: 90% h1≤h3≤35%H.

4. The pre-combustion chamber according to claim 1, characterized in that: A distance h0 between the ground electrode (2011) and the upper end of the second chamber (102), and a distance h4 between the ground electrode (2011) and the upper end of the first chamber (101), satisfy the following relationship: h0≤30%h4.

5. The pre-combustion chamber according to claim 1, characterized in that: The distance h4 between the ground electrode (2011) and the upper end of the first chamber (101), the height H of the pre-combustion chamber, and the diameter D of the spark plug (2) satisfy the following conditions: 30%H≤h4≤40%H, and 50%D≤h4≤70%D.

6. The pre-combustion chamber according to claim 1, characterized in that: The distance h6 between the second flame-spraying hole (103212), the connecting opening of the arc-shaped cavity portion (1032) and the grounding electrode (2011), and the height H of the pre-combustion cavity satisfy the following relationship: h6≤70%H.

7. The pre-combustion chamber according to any one of claims 1 to 6, characterized in that: The number of the flame-spraying holes (10321) is between 4 and 8, and the diameter of the flame-spraying holes (10321) is between 0.8 and 2 mm.

8. An engine, characterized in that: The engine comprises a pre-combustion chamber as claimed in any one of claims 1 to 7, and the housing (1) is integrated into a cylinder head of the engine; or, the housing (1) is integrated on the spark plug (2).

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