Multi-spark-plug ignition system, combustion chamber and gas engine
By combining the pre-combustion chamber and the second spark plug in the multi-spark plug ignition system, the problems of slow flame propagation and high knocking tendency in heavy-duty gas engines are solved, achieving rapid flame propagation and reduced knocking.
Patent Information
- Application Number
- CN202520267336.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-19
- Publication Date
- 2025-11-21
- Estimated Expiration
- 2035-02-19
AI Technical Summary
In heavy-duty gas engines, where high power density and transient response are required, traditional single spark plug ignition systems result in long flame propagation distances, increased knocking tendency, and reduced efficiency.
It adopts a multi-spark plug ignition system, combined with the design of a pre-combustion chamber and a second spark plug. The pre-combustion chamber is located in the center of the dome structure, with the nozzle pointing towards the high-frequency detonation area. The second spark plug is close to the edge of the dome. It adopts a high-speed jet and center ignition method to form a compact and large combustion space and improve the flame propagation speed.
It effectively shortens flame propagation time, reduces detonation tendency, and improves combustion efficiency and response speed.
Smart Images
Figure CN223578101U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to the technical field of engine, especially a multi-spark plug ignition system, a combustion chamber and a gas engine. BACKGROUND
[0002] Heavy gas machines bear heavy load transportation work daily, so there are higher requirements for the power density and transient response of the engine. On the other hand, from the national five to the national six gas machine, the equivalent ratio and EGR (Exhaust Gas Recirculation) collaborative control technology route is adopted, which increases the tendency of knock compared with lean burn, and the main means to control knock is to delay the ignition angle, which often leads to the reduction of efficiency and the delay of response.
[0003] The traditional spark-ignition engine adopts a single spark plug ignition mode, and the spark plug ignition feature is central ignition flame propagation. Due to the large cylinder diameter of the heavy-duty engine, the flame propagation distance is long, and the molecular structure of natural gas is stable, and the laminar flame speed is low, which causes the flame to propagate to the edge of the combustion chamber for a long time, thus further increasing the tendency of knock. SUMMARY
[0004] The first purpose of the utility model is to provide a multi-spark plug ignition system to accelerate flame propagation and make the flame reach the edge of the engine combustion chamber as soon as possible to reduce the tendency of knock.
[0005] The second purpose of the utility model is to provide a combustion chamber and a gas engine comprising the above multi-spark plug ignition system.
[0006] To achieve the above purpose, the utility model provides the following technical scheme:
[0007] A multi-spark plug ignition system for the cylinder head of an engine, the bottom surface of the cylinder head is provided with a dome structure for surrounding a combustion chamber with a piston and a cylinder of the engine, the cylinder head comprises an intake port and an exhaust port, the intake port and the exhaust port are in communication with the dome structure, and the multi-spark plug ignition system further comprises:
[0008] A pre-chamber is arranged in the center of the dome structure, a first spark plug is arranged in the pre-chamber, a plurality of injection holes are arranged in the pre-chamber in a circumferential direction, and at least one injection hole is directed to a high-frequency knock area near an exhaust throat of the exhaust port in the combustion chamber;
[0009] A second spark plug is arranged between the intake port and the exhaust port at a distance from the pre-chamber, and the second spark plug is close to the edge of the dome structure.
[0010] In one embodiment of the present application, the axis of the second spark plug intersects with the ridge line of the dome structure.
[0011] In one embodiment of the present application, the second spark plug is arranged obliquely so that the ignition end of the second spark plug is inclined toward the pre-chamber.
[0012] In one embodiment of the present application, the second spark plug is arranged symmetrically on both sides of the pre-chamber.
[0013] In one embodiment of the present application, the cylinder head is provided with two intake ports and two exhaust ports, the intake ports are symmetrically arranged about the longitudinal symmetry plane of the dome structure, the exhaust ports are symmetrically arranged about the longitudinal symmetry plane of the dome structure, the longitudinal symmetry plane of the dome structure is a plane perpendicular to and bisecting the ridge line of the dome structure, the second spark plug and the pre-chamber are arranged on both sides of the axis connecting the intake port and the exhaust port on the same side of the longitudinal symmetry plane.
[0014] In one embodiment of the present application, the pre-chamber includes at least eight injection holes in the directions of the two intake ports, the direction between the two intake ports, the direction of the two exhaust ports, the direction between the two exhaust ports, and the direction of the two second spark plugs.
[0015] A combustion chamber surrounded by a cylinder head, a cylinder, and a piston, wherein the cylinder head is provided with the multi-spark plug ignition system according to any one of the above.
[0016] In one embodiment of the present application, the top surface of the piston is provided with a central boss and a combustion chamber pit surrounding the central boss, the boss top surface of the central boss facing the opening of the combustion chamber pit is connected with the bottom of the combustion chamber pit through a first guide wall surface, the bottom of the combustion chamber pit and the piston top surface surrounding the combustion chamber pit are connected through a second guide wall surface, the first guide wall surface and the second guide wall surface are smoothly connected, the first guide wall surface gradually expands in the direction from the boss top surface of the central boss to the bottom of the combustion chamber pit, the second guide wall surface gradually shrinks in the direction from the piston top surface to the bottom of the combustion chamber pit, and the injection holes of the pre-chamber of the multi-spark plug ignition system are arranged along the first guide wall surface toward the second guide wall surface.
[0017] In one embodiment of the present application, the plane passing through the central axis of the piston is the piston symmetry plane, the intersection line between the first guide wall surface and the piston symmetry plane is an inclined straight line segment, and the intersection line between the second guide wall surface and the piston symmetry plane is a circular arc line segment or an inclined straight line segment.
[0018] A gas engine comprising a combustion chamber as claimed in any one of the preceding claims.
[0019] It can be seen from the above technical solutions that the multi-spark plug ignition system is used for a cylinder head of an engine, the bottom surface of the cylinder head is provided with a dome structure for surrounding a combustion chamber with a piston and a cylinder of the engine, the cylinder head comprises an intake passage and an exhaust passage, the intake passage and the exhaust passage are respectively communicated with the dome structure, the multi-spark plug ignition system further comprises a pre-chamber and a second spark plug, wherein the pre-chamber is arranged at the center of the dome structure, the first spark plug is arranged in the pre-chamber, a plurality of injection holes are arranged in the pre-chamber in a circumferential direction, at least one injection hole is directed to a high-frequency knock area near an exhaust throat of the exhaust passage in the combustion chamber, and the second spark plug is arranged between the intake passage and the exhaust passage in a spaced manner with the pre-chamber, and the second spark plug is close to the edge of the dome structure.
[0020] The multi-spark plug ignition system in the application adopts a combined design of the first spark plug in the pre-chamber and the second spark plug outside the pre-chamber, the pre-chamber is located at the center of the dome structure, and in general, the higher the temperature in the combustion chamber, the higher the knock tendency, therefore, at least one injection hole of the pre-chamber is directed to the high-frequency knock area near the exhaust throat of the exhaust passage in the combustion chamber, the ignition mode of the pre-chamber is high-speed jet, the second spark plug is located between the intake throat and the exhaust throat, and the ignition mode of the second spark plug is that the central ignition flame spreads to the periphery, therefore, through the above design, a relatively compact combustion space is formed between the dome structure and the piston in the tumble flow parallel plane, i.e. the direction from the intake valve to the exhaust valve, the high-speed jet of the pre-chamber can make the flame reach the edge of the combustion chamber as soon as possible, and the knock tendency is reduced, and in the tumble flow vertical plane, i.e. along the ridge line direction of the dome structure, a relatively large combustion space is formed between the dome structure and the piston, and the pre-chamber and the second spark plug close to the edge of the dome structure cooperate to accelerate the combustion in this combustion space at the same time, thereby reducing the knock tendency here, and it can be seen that the multi-spark plug ignition system can effectively improve the flame propagation speed, shorten the time of flame propagation to the edge of the combustion chamber, make the flame reach the edge of the combustion chamber of the engine as soon as possible, and achieve the purpose of reducing the knock tendency. BRIEF DESCRIPTION OF DRAWINGS
[0021] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or the prior art description. Obviously, the drawings in the following description only show some of the embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort based on these drawings.
[0022] Figure 1 The dome structure in the present application provides a schematic diagram of the distribution of the knock tendency.
[0023] Figure 2 The bottom view of the dome structure provided by the embodiment of the utility model,
[0024] Figure 3 The cross-sectional view of the combustion chamber along the tumble flow parallel surface provided by the embodiment of the utility model,
[0025] Figure 4 The cross-sectional view of the combustion chamber along the tumble flow vertical surface provided by the embodiment of the utility model,
[0026] Figure 5 The schematic diagram of the jet hole orientation of the precombustion chamber in the multi-spark plug ignition system provided by the embodiment of the utility model,
[0027] Figure 6 The cross-sectional view of the piston of the combustion chamber provided by the embodiment of the utility model.
[0028] In the drawing,
[0029] 1 is a cylinder cover; 2 is a dome structure; 3 is an air inlet throat; 4 is an exhaust throat; 5 is a precombustion chamber; 6 is a second spark plug; 7 is a piston; 701 is a center boss; 702 is a combustion chamber pit; 703 is a boss top surface; 704 is a first guide wall surface; 705 is a piston top surface; 706 is a second guide wall surface; 8 is a cylinder; 9 is an air inlet valve; 10 is an exhaust valve; 11 is a high-speed jet. DETAILED DESCRIPTION
[0030] One of the cores of the utility model is to provide a multi-spark plug ignition system, the structural design of the multi-spark plug ignition system makes it possible to accelerate flame propagation, so that the flame reaches the edge of the combustion chamber of the engine as soon as possible, and the knocking tendency is reduced.
[0031] Another core of the utility model is to provide a combustion chamber and a gas engine based on the above multi-spark plug ignition system.
[0032] The technical solutions in the embodiments of the utility model will be clearly and completely described below with reference to the drawings in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the utility model.
[0033] Please refer to Figure 1 and Figure 2 , Figure 1 The schematic diagram of the knocking tendency distribution in the dome structure provided by the embodiment of the utility model, Figure 2 The bottom view of the dome structure provided by the embodiment of the utility model.
[0034] The utility model discloses a kind of multiple spark plug ignition systems, to reduce the occurrence of knock in combustion chamber, knock is the spontaneous combustion phenomenon produced before flame propagation reaches end mixture, when spontaneous combustion ratio reaches certain value, two flame propagation superposition generates shock wave, and then pressure oscillation occurs in main combustion chamber.Therefore, the occurrence of knock and the flow field in cylinder, flame propagation situation and hot spot in cylinder exist certain relationship, generally speaking, the position of exhaust throat 4 is washed by high-temperature exhaust, wall surface temperature is very high, therefore hot spot region is located in the vicinity of exhaust throat 4, if there is mixture concentration and flow field suitable for ignition in hot spot region simultaneously, then spontaneous combustion is relatively easy to occur.Visualization and combustion simulation of combustion can identify the spontaneous combustion and pressure oscillation of subregion, as shown in Figure 1 D, E, F region near exhaust throat 4 has the highest knock tendency, C, G region between intake throat 3 and exhaust throat 4 has the second knock tendency, B, H region close to intake throat 3 has lower knock tendency than C, G region, and A region farthest from exhaust throat 4 has relatively lowest knock tendency, the case is designed to increase flame propagation speed by ignition system, to prevent spontaneous combustion produced before flame propagation reaches.
[0035] As shown in Figure 2 As shown in the figure, the multiple spark plug ignition system is used for cylinder cover 1 of engine, the bottom surface of cylinder cover 1 is provided with dome structure 2 for surrounding combustion chamber with piston 7 and cylinder 8 of engine, cylinder cover 1 includes intake passage and exhaust passage, intake passage and exhaust passage are communicated with dome structure 2 respectively, intake passage is provided with intake throat at the communicated place of dome structure 2, intake throat is provided with intake valve 9, exhaust passage is provided with exhaust throat at the communicated place of dome structure 2, exhaust throat is provided with exhaust valve 10, the multiple spark plug ignition system further includes prechamber 5 and second spark plug 6.
[0036] Prechamber 5 is arranged in the center of dome structure 2, the center here refers to the central region of dome structure 2, and is not limited to the exact center of dome structure 2, that is, prechamber 5 can be arranged in the center of dome structure 2, or can be arranged in the position of central region deviated from intake throat or exhaust throat, first spark plug is arranged in prechamber 5, prechamber 5 is circumferentially spaced apart multiple injection holes, each injection hole can be uniformly distributed along the circumference of prechamber 5, or can be asymmetrically designed according to the knock tendency distribution of visualization or simulation as shown in Figure 1 At least one injection hole points to high-frequency knock region near exhaust throat 4 of exhaust passage in combustion chamber, second spark plug 6 is arranged between intake passage and exhaust passage at a distance from prechamber 5, and second spark plug 6 is close to the edge of dome structure 2.
[0037] Compared with the prior art, the multi-spark plug ignition system provided in this embodiment of the utility model adopts a combination design of a first spark plug in the pre-combustion chamber 5 and a second spark plug 6 outside the pre-combustion chamber 5. The pre-combustion chamber 5 is located in the center of the dome structure 2. Generally speaking, the higher the temperature in the combustion chamber, the higher the knocking tendency. Therefore, at least one nozzle of the pre-combustion chamber 5 is pointed towards the high-frequency knocking area near the exhaust throat 4 of the exhaust passage in the combustion chamber. The ignition method of the pre-combustion chamber 5 is a high-speed jet 11. The second spark plug 6 is located between the intake throat 3 and the exhaust throat 4. The ignition method of the second spark plug 6 is a central ignition flame that spreads to the surrounding areas. Therefore, through the above design, in the tumble parallel plane, such as Figure 3 As shown, from the intake throat to the exhaust throat, a relatively compact combustion space is formed between the dome structure 2 and the piston 7. The cone angle of the high-speed jet 11 ejected from the pre-combustion chamber 5 corresponds to the cone angle of the dome structure 2, that is, they are equal or approximately equal. The high-speed jet 11 ejected from the pre-combustion chamber 5 can enable the flame to reach the edge of the combustion chamber as quickly as possible, reducing the tendency for knocking. On the vertical plane of the tumble flow, such as Figure 4 As shown, along the ridge line of the dome structure 2, a relatively large combustion space is formed between the dome structure 2 and the piston 7. The pre-combustion chamber 5, together with the second spark plug 6 near the edge of the dome structure 2, can simultaneously accelerate the combustion in this combustion space, thereby reducing the tendency of knocking at this location.
[0038] It is evident that the aforementioned multi-spark plug ignition system can effectively increase the flame propagation speed, shorten the time it takes for the flame to reach the edge of the combustion chamber, and enable the flame to reach the edge of the engine's combustion chamber as quickly as possible, thereby reducing the tendency for knocking.
[0039] In one embodiment of this application, such as Figure 4 As shown, the axis of the second spark plug 6 intersects the ridge line of the dome structure 2. Furthermore, in this embodiment, the axis of the second spark plug 6 and the axis of the pre-combustion chamber 5 are located on the same plane. Of course, it should be noted that the arrangement of the second spark plug 6 is not limited to this. For example, in other embodiments, the second spark plug 6 can also be arranged on the side of the ridge line of the dome structure 2 near the exhaust port 4.
[0040] like Figure 4 As shown in the illustrated embodiment, the second spark plug 6 is inclined so that the ignition end of the second spark plug 6 is biased toward the pre-combustion chamber 5, so as to ignite the mixture in the space between the high-speed jet 11 and the ridge of the dome structure 2 at the edge of the combustion chamber and to allow flame propagation.
[0041] It should be noted that the second spark plug 6 can be installed only on one side of the pre-combustion chamber 5, or it can be installed as follows: Figure 4 In the embodiment shown, second spark plugs 6 are symmetrically arranged on both sides of the pre-combustion chamber 5 as needed.
[0042] likeFigure 1 and Figure 2 As shown, under normal circumstances, the cylinder head 1 is provided with two intake ports and two exhaust ports. The intake throats 3 of the two intake ports are symmetrically arranged about the longitudinal symmetry plane of the dome structure 2, and the exhaust throats 4 of the two exhaust ports are symmetrically arranged about the longitudinal symmetry plane of the dome structure 2. The longitudinal symmetry plane of the dome structure 2 is a plane that is perpendicular to and bisects the ridge line of the dome structure 2. The second spark plug 6 and the pre-combustion chamber 5 are respectively arranged on both sides of the axis connecting the intake throat 3 and the exhaust throat 4 on the same side of the longitudinal symmetry plane, so that the second spark plug 6 is arranged as close as possible to the edge of the dome structure 2.
[0043] like Figure 5 As shown, in one embodiment of this application, the pre-combustion chamber 5 includes at least eight nozzles pointing in the directions of the two air intake ports 3, the direction between the two air intake ports 3, the direction of the two exhaust ports 4, the direction between the two exhaust ports 4, and the direction of the two second spark plugs 6. The eight nozzles point to regions A, B, C, D, E, F, G, and H, respectively. Since regions C and G have larger spaces, the high-speed jet 11 from the pre-combustion chamber 5 and the second spark plugs 6 simultaneously accelerate combustion in these regions, significantly reducing the knocking tendency in these regions. Regions A, B, D, E, F, and H have smaller spaces due to the influence of the dome structure 2, and the high-speed jet 11 from the pre-combustion chamber 5 accelerates combustion in these six regions.
[0044] The multi-spark plug ignition system provided in this application embodiment can adopt multiple working modes, as detailed below.
[0045] Operating mode 1: The first spark plug in the pre-combustion chamber 5 ignites first, and the second spark plug 6 ignites later. This mode is suitable for areas with a high tendency to knock, located in regions D, E, and F. The distribution of the high-speed jet 11 allows the flame to reach the edge of the combustion chamber as quickly as possible, reducing the tendency to knock. The second spark plug 6 accelerates the flame propagation in regions C and G.
[0046] Operating mode 2: The second spark plug 6 ignites first, and the first spark plug in the pre-combustion chamber 5 ignites later. This mode is suitable for areas with a high tendency to knock, located in the C and G regions. The ignition of the second spark plug 6 ignites the mixture at the edge of the combustion chamber and the flame spreads. Then, the distribution of the high-speed jet 11 in the pre-combustion chamber 5 is used to accelerate the combustion in other regions, thereby improving the combustion speed together.
[0047] Operating Mode 3: The first spark plug and the second spark plug 6 ignite simultaneously. This operating mode is suitable for situations where the knock tendency is not high. Setting different ignition sequences for the first spark plug and the second spark plug 6 does not provide significant benefits compared to simultaneous ignition. In this case, simultaneous ignition greatly reduces the calibration workload. Another applicable scenario for this operating mode is when the knock tendency is high, but the area with the most prominent knock tendency cannot be identified through simulation or visualization analysis. That is, the knock area may be located in several different locations, and it is impossible to further reduce knock by optimizing the ignition sequence of the first spark plug and the second spark plug 6.
[0048] This application embodiment also provides a combustion chamber, which is surrounded by a cylinder head 1, a cylinder 8 and a piston 7. The cylinder head 1 is provided with a multi-spark plug ignition system as described in the above embodiment. Since the combustion chamber adopts the multi-spark plug ignition system in the above embodiment, the technical effect of the combustion chamber is as described in the above embodiment.
[0049] To improve the gas mixing effect and further accelerate the flame propagation speed, in this application, such as Figure 6 As shown, the piston 7 has a central boss 701 on its top surface and a combustion chamber recess 702 surrounding the central boss 701. The top surface 703 of the central boss 701 facing the opening of the combustion chamber recess 702 is connected to the bottom of the combustion chamber recess 702 by a first guide wall 704. The bottom of the combustion chamber recess 702 is connected to the piston top surface 705 of the piston 7 surrounding the combustion chamber recess 702 by a second guide wall 706. The first guide wall 704 extends from the top surface 703 of the boss to the combustion chamber. The bottom of the recess 702 gradually widens, while the second guide wall 706 gradually narrows from the piston top surface 705 to the bottom of the combustion chamber recess 702. The first guide wall 704 and the second guide wall 706 are smoothly connected. The nozzle of the pre-combustion chamber 5 of the multi-spark plug ignition system faces the second guide wall 706 along the first guide wall 704. The cooperation of the first guide wall 704 and the second guide wall 706 can guide the high-speed jet 11 of the pre-combustion chamber 5, disturbing the gas and air in the combustion chamber. This improves the gas-air mixing process, making the gas and air mix more uniform, thereby improving the entire combustion process and also being more conducive to flame propagation.
[0050] To further optimize the above technical solution, in one embodiment of this application, such as... Figure 6 As shown, the plane passing through the central axis of piston 7 is the symmetry plane of piston 7. The intersection of the first guide wall 704 and the symmetry plane of piston 7 is an inclined straight line segment. The intersection of the second guide wall 706 and the symmetry plane of piston 7 is an arc segment or an inclined straight line segment.
[0051] The application further provides a gas engine comprising the combustion chamber as described in the above embodiments, and since the gas engine adopts the combustion chamber in the above embodiments, the technical effects of the gas engine refer to the above embodiments.
[0052] It should be noted that each of the embodiments in the specification adopts a progressive manner for description, and each of the embodiments focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other.
[0053] The principle and implementation mode of the present application are described by using specific examples, and the above embodiment is only used to help understand the core idea of the present application. It should be pointed out that for ordinary skilled in the art, without departing from the principle of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the protection scope of the claims of the present application.
Claims
1. A multiple spark plug ignition system for a cylinder head (1) of an engine, a bottom surface of the cylinder head (1) being provided with a dome structure (2) for enclosing a combustion chamber with a piston (7) and a cylinder (8) of the engine, the cylinder head (1) comprising an intake passage and an exhaust passage, respectively, which communicate with the dome structure (2), characterized in that, The multi-spark plug ignition system further comprises: a pre-chamber (5) arranged in the center of the dome structure (2), a first spark plug arranged in the pre-chamber (5), and a plurality of injection holes circumferentially arranged in the pre-chamber (5), at least one of the injection holes pointing to a high-frequency knock area near an exhaust port (4) of the exhaust passage in the combustion chamber; a second spark plug (6) arranged between the intake passage and the exhaust passage at a distance from the pre-chamber (5), and close to the edge of the dome structure (2).
2. The multiple spark plug ignition system of claim 1 wherein, The axis of the second spark plug (6) intersects the ridge line of the dome structure (2).
3. The multiple spark plug ignition system of claim 1 wherein, The second spark plug (6) is arranged obliquely so that the ignition end of the second spark plug (6) is inclined toward the pre-chamber (5).
4. The multiple spark plug ignition system of any one of claims 1-3, wherein, The second spark plug (6) is symmetrically arranged on both sides of the pre-chamber (5).
5. The multiple spark plug ignition system of claim 4 wherein, The cylinder head (1) is provided with two intake passages and two exhaust passages, the intake ports (3) of the two intake passages are symmetrically arranged about the longitudinal symmetry plane of the dome structure (2), the exhaust ports (4) of the two exhaust passages are symmetrically arranged about the longitudinal symmetry plane of the dome structure (2), the longitudinal symmetry plane of the dome structure (2) is a plane perpendicular to and bisecting the ridge line of the dome structure (2), and the second spark plug (6) and the pre-chamber (5) are arranged on both sides of the axis connecting the intake port (3) and the exhaust port (4) on the same side of the longitudinal symmetry plane.
6. The multiple spark plug ignition system of claim 5 wherein, The pre-chamber (5) comprises at least eight injection holes in the directions of the two intake ports (3), the direction between the two intake ports (3), the direction of the two exhaust ports (4), the direction between the two exhaust ports (4), and the direction of the two second spark plugs (6).
7. A combustion chamber, which is surrounded by a cylinder head (1), a cylinder (8), and a piston (7), characterized in that, The cylinder head (1) is provided with the multi-spark plug ignition system according to any one of claims 1-6.
8. The combustion chamber of claim 7, wherein The top surface of the piston (7) is provided with a center boss (701) and a combustion chamber pit (702) surrounding the center boss (701), the top surface of the boss opening of the combustion chamber pit (702) is connected with the bottom of the combustion chamber pit (702) through a first guide wall surface (704), the bottom of the combustion chamber pit (702) is connected with the piston top surface (705) of the piston (7) surrounding the combustion chamber pit (702) through a second guide wall surface (706), the first guide wall surface (704) and the second guide wall surface (706) are smoothly connected, the first guide wall surface (704) is gradually expanded along the boss top surface (703) of the center boss (701) to the bottom of the combustion chamber pit (702), the second guide wall surface (706) is gradually contracted along the piston top surface (705) to the bottom of the combustion chamber pit (702), the injection hole of the precombustion chamber (5) of the multi-spark plug ignition system is along the first guide wall surface (704) towards the second guide wall surface (706).
9. The combustion chamber of claim 8, wherein, The plane passing through the central axis of the piston (7) is the symmetry plane of the piston (7), the intersection line of the first guide wall surface (704) and the symmetry plane of the piston (7) is an inclined straight line segment, and the intersection line of the second guide wall surface (706) and the symmetry plane of the piston (7) is an arc line segment or an inclined straight line segment.
10. A gas engine characterized in that, The gas engine comprises the combustion chamber as claimed in any one of claims 7-9.