Combustion system and internal combustion engine

Abstract

This utility model relates to a combustion system and an internal combustion engine. The combustion system includes a piston and a fuel injector. A combustion chamber recess is provided on the top of the piston. A first circumferential flange is provided on the circumferential surface of the combustion chamber recess. A central boss is provided at the bottom of the combustion chamber recess, and a projectile boss is provided on the circumferential surface of the central boss. The fuel injector is disposed on the cylinder head and has multiple first nozzles and multiple second nozzles arranged circumferentially. The first nozzles face the first circumferential flange, and the second nozzles face the projectile boss. By providing a projectile boss on the central boss of the piston's combustion chamber recess, the combustion system can promote the diffusion of the air-fuel mixture to the upper and lower regions of the combustion chamber and the region near the fuel injector nozzles. This improves the space utilization near the fuel injector nozzles and the uniformity of the air-fuel mixture distribution throughout the combustion chamber, thereby improving combustion quality and ultimately enhancing engine performance.

Description

Technical Field

[0001] This utility model relates to the field of internal combustion engine technology, and in particular to a combustion system and an internal combustion engine. Background Technology

[0002] Diesel engines employ a combination of premixed and diffusion combustion, with diffusion combustion being the dominant method. Therefore, the uniformity of the air-fuel mixture distribution is crucial to engine performance. In traditional combustion systems, the fuel jet injected by the fuel injector is guided by structures such as the throat of the combustion pit at the top of the piston and the arc at the bottom, thus distributing the air-fuel mixture relatively evenly across most of the combustion chamber. However, the space utilization near the fuel injector nozzle is low. Even when the rest of the combustion chamber is filled with a uniform mixture, the area near the fuel injector nozzle may not have sufficient mixture. This significantly reduces the overall space utilization of the combustion chamber, hindering engine performance improvements. Utility Model Content

[0003] The first objective of this invention is to provide a combustion system that improves the space utilization near the nozzle of the fuel injector and the uniformity of the mixture distribution throughout the combustion chamber.

[0004] The second objective of this invention is to provide an internal combustion engine that includes the above-described combustion system.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] In a first aspect of this application, a combustion system is provided, comprising:

[0007] The piston has a combustion chamber recess on its top, a first circumferential flange on the circumferential surface of the combustion chamber recess, a central boss protruding towards the bottom surface of the cylinder head of the combustion system at the bottom of the combustion chamber recess, and a projectile boss on the circumferential surface of the central boss.

[0008] A fuel injector is disposed on the cylinder head. The fuel injector has a plurality of first nozzles and a plurality of second nozzles arranged circumferentially. Along the axial direction of the fuel injector, the second nozzles are farther away from the cylinder head than the first nozzles. The first nozzles face the first circumferential flange, and the second nozzles face the projectile boss.

[0009] In one possible implementation, the diameter of the second nozzle is smaller than the diameter of the first nozzle.

[0010] In one possible implementation, the injection cone angle of the first nozzle is greater than that of the second nozzle.

[0011] In one possible implementation, the plane passing through the piston axis is the central symmetry plane of the piston, the intersection of the central symmetry plane and the projectile boss is the projectile boss profile, the intersection of the central symmetry plane and the central boss is the central boss profile, the projectile boss profile includes a first projectile profile facing the second nozzle and a second projectile profile facing away from the second nozzle, the first end of the first projectile profile and the first end of the second projectile profile are respectively smoothly connected to the central boss profile, the second end of the first projectile profile and the second end of the second projectile profile are smoothly connected, and the distance between the first projectile profile and the second projectile profile decreases as the distance from the central boss profile increases.

[0012] In one possible implementation, the first projectile profile is a straight segment or an arc segment concave towards the second projectile profile, and the second projectile profile is a straight segment or an arc segment concave towards the first projectile profile.

[0013] In one possible implementation, the central boss profile includes two circumferential surface profiles and a top surface profile that smoothly connects the two circumferential surface profiles. The circumferential surface profiles include a first surface profile and a second surface profile distributed on both sides of the projectile boss profile. The first surface profile is a straight segment or an arc segment recessed towards the axis of the piston, and the second surface profile is a straight segment or an arc segment recessed towards the axis of the piston.

[0014] In one possible implementation, the intersection line of the central symmetry plane and the circumferential surface of the combustion chamber recess includes a first guide line, a first circumferential flange line, and a second guide line connected in sequence. The first guide line, the first circumferential flange line, and the second guide line are smoothly connected in sequence along the direction from the bottom of the combustion chamber recess to the top of the piston. The end of the first guide line away from the first circumferential flange line is smoothly connected to the central boss line.

[0015] In one possible implementation, the first guide profile is an arc segment that is concave in the direction away from the axis of the piston, the first circumferential flange profile is an arc segment that is concave in the direction of the axis of the piston, and the second guide profile is a straight line segment or an arc segment that is concave in the direction away from the axis of the piston, starting from one end connected to the first circumferential flange profile.

[0016] In one possible implementation, a second circumferential flange is provided on the circumferential surface of the combustion chamber recess. The intersection of the second circumferential flange and the central symmetry plane is a second circumferential flange profile. The second circumferential flange profile is an arc segment recessed towards the axis of the piston. One end of the second circumferential flange profile is smoothly connected to the second guide profile, and the other end is connected to the top surface profile formed by the intersection of the top surface of the piston and the central symmetry plane.

[0017] As can be seen from the above technical solutions, this utility model discloses a combustion system, which includes a piston and a fuel injector. The piston has a combustion chamber recess on its top, a first circumferential flange on the circumferential surface of the combustion chamber recess, and a central boss protruding towards the bottom surface of the cylinder head of the combustion system at the bottom of the combustion chamber recess. The circumferential surface of the central boss has a projectile boss. The fuel injector is disposed on the cylinder head and has multiple first nozzles and multiple second nozzles circumferentially arranged. Along the axial direction of the fuel injector, the second nozzles are farther away from the cylinder head than the first nozzles. The first nozzles face the first circumferential flange, and the second nozzles face the projectile boss.

[0018] It should be noted that the circumferential surface of the combustion chamber recess also includes a first guide surface and a second guide surface disposed on both sides of the first circumferential flange. The first guide surface is located on the side of the first circumferential flange away from the cylinder head, and the second guide surface is located on the side of the second circumferential flange closer to the cylinder head. The first guide surface is used to guide the air-fuel mixture to the bottom of the combustion chamber recess, that is, to diffuse the air-fuel mixture into the lower region of the combustion chamber. The second guide surface is used to guide the air-fuel mixture to the top opening of the combustion chamber recess, that is, to diffuse the air-fuel mixture into the upper region of the combustion chamber.

[0019] In application, the fuel jet ejected from the first nozzle impacts the first circumferential flange and then diffuses to both sides of the first circumferential flange, moving along the first guide surface and the second guide surface respectively. This breaks and atomizes the fuel jet ejected from the first nozzle, reducing the central concentration of the fuel jet ejected from the first nozzle. One stream of the fuel jet ejected from the first nozzle moves along the first guide surface to the bottom of the combustion chamber recess and changes direction along the central boss. After contacting the ejection boss, it changes direction again and moves towards the top of the combustion chamber recess. The other stream moves along the second guide surface to the top of the combustion chamber recess, thus forming a diffusion of the fuel jet into the upper and lower regions of the combustion chamber. At the same time, the fuel jet ejected from the second nozzle impacts the ejection boss and then changes direction to move towards the top of the combustion chamber recess, realizing the diffusion of the mixture into the region near the nozzle of the fuel injector.

[0020] It is evident that the combustion system described above, by setting a projectile protrusion on the central protrusion of the piston's combustion chamber recess, can promote the diffusion of the air-fuel mixture to the upper and lower regions of the combustion chamber and the region near the fuel injector nozzle, thereby improving the space utilization near the fuel injector nozzle and the uniformity of the air-fuel mixture distribution throughout the combustion chamber, improving combustion quality, and thus enhancing engine performance.

[0021] In a second aspect of this application, an internal combustion engine is provided, including a combustion system as described in the first aspect and its possible implementations.

[0022] Since the internal combustion engine employs the combustion system described in the first aspect and its possible implementations, it should therefore have the same beneficial effects as the combustion system, which will not be elaborated upon here. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A top view of the combustion chamber recess of the piston in the combustion system provided in an embodiment of this utility model;

[0025] Figure 2 A cross-sectional view of the fuel injector of the combustion system provided in an embodiment of this utility model;

[0026] Figure 3 A cross-sectional view of the combustion system provided in an embodiment of this utility model.

[0027] In the picture:

[0028] 100 is the combustion chamber recess; 110 is the circumferential surface of the combustion chamber recess; 111 is the first guide surface; 112 is the first circumferential flange; 113 is the second guide surface; 114 is the second circumferential flange; 120 is the central boss; 121 is the surface of the first boss; 122 is the surface of the second boss; 123 is the top curved surface; 130 is the projectile boss; 131 is the first projectile surface; 132 is the second projectile surface; 133 is the transition curved surface;

[0029] 200 is the fuel injector; 210 is the first nozzle; 220 is the second nozzle. Detailed Implementation

[0030] One of the core features of this invention is to provide a combustion system whose structural design enables it to improve the space utilization near the fuel injector nozzle and the uniformity of the air-fuel mixture distribution throughout the combustion chamber, thereby improving combustion quality and enhancing engine performance.

[0031] Another core aspect of this invention is to provide an internal combustion engine that includes the aforementioned combustion system.

[0032] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0033] This application provides a combustion system; please refer to [link / reference]. Figure 1 and Figure 3 The combustion system includes a piston and a fuel injector 200. It should be noted that the combustion system includes more than just a piston and a fuel injector 200. As those skilled in the art know, the combustion system of an internal combustion engine also includes at least a cylinder head and a cylinder. The cylinder head is located above the cylinder and is sealed to the cylinder. The piston is reciprocally positioned inside the cylinder. The cylinder head, cylinder, and piston form a combustion chamber. The cylinder head is provided with an intake manifold, an exhaust manifold, an intake throttle valve, and an exhaust throttle valve. The intake manifold and exhaust manifold are respectively connected to the combustion chamber. The intake throttle valve is located in the intake manifold and is used to control the intake of the combustion chamber. The exhaust throttle valve is located in the exhaust manifold and is used to control the exhaust of the combustion chamber.

[0034] In this application, a combustion chamber recess 100 is provided on the top of the piston. A first circumferential flange 112 is provided on the circumferential surface 110 of the combustion chamber recess 100. A central boss 120 protruding towards the bottom surface of the cylinder head of the combustion system is provided at the bottom of the combustion chamber recess 100. A projectile boss 130 is provided on the circumferential surface of the central boss 120. The circumferential surface of the central boss 120 includes a first boss surface 121 located on the side of the projectile boss 130 near the bottom of the combustion chamber recess 100 and a second boss surface 122 located on the side of the projectile boss 130 near the top of the combustion chamber recess 100. Both the first boss surface 121 and the second boss surface 122 are circumferentially closed surfaces of revolution. The top surface 123 of the central boss 120 is a spherical surface or a smooth surface.

[0035] like Figure 3As shown, the fuel injector 200 is disposed on the cylinder head. The fuel injector 200 is usually coaxial with the piston. The fuel injector 200 is provided with a plurality of first nozzles 210 and a plurality of second nozzles 220 along the circumferential direction. The spacing between two adjacent first nozzles 210 in the circumferential direction can be the same or different. Correspondingly, the spacing between two adjacent second nozzles 220 in the circumferential direction can be the same or different. The number of first nozzles 210 and the number of second nozzles 220 can be the same or different. In one embodiment of this application, each first nozzle 210 is evenly distributed along the circumferential direction, and each second nozzle 220 is evenly distributed along the circumferential direction. In actual manufacturing, it is impossible for the first nozzles 210 and the second nozzles 220 to be strictly evenly distributed along the circumferential direction. The non-strict even distribution of the first nozzles 210 and the second nozzles 220 in the circumferential direction due to process errors and human errors is also within the protection scope of this solution.

[0036] Along the axial direction of the fuel injector 200, the second nozzle 220 is farther away from the cylinder head than the first nozzle 210. The first nozzle 210 faces the first circumferential flange 112, and the second nozzle 220 faces the projectile boss 130.

[0037] It should be noted that the circumferential surface 110 of the combustion chamber recess 100 also includes a first guide surface 111 and a second guide surface 113 disposed on both sides of the first circumferential flange 112. The first guide surface 111 is located on the side of the first circumferential flange 112 away from the cylinder head, and the second guide surface 113 is located on the side of the second circumferential flange 114 close to the cylinder head. The first guide surface 111 is used to guide the air-fuel mixture to the bottom of the combustion chamber recess 100, that is, to allow the air-fuel mixture to diffuse into the lower region of the combustion chamber. The second guide surface 113 is used to guide the air-fuel mixture to the top opening of the combustion chamber recess 100, that is, to allow the air-fuel mixture to diffuse into the upper region of the combustion chamber.

[0038] To reduce resistance to the fuel jet and its air-fuel mixture, the first guide surface 111 and the second guide surface 113 are smooth curved surfaces or a combination of smooth curved surfaces and planes. Both the first guide surface 111 and the second guide surface 113 are rotary curved surfaces that surround the piston axis and are closed in the circumferential direction.

[0039] In addition to the first guide surface 111 and the second guide surface 113, the circumferential surface 110 of the combustion chamber recess 100 may also include other guide surfaces, which are not limited here.

[0040] In application, the fuel jet ejected from the first nozzle 210 impacts the first circumferential flange 112 and then diffuses to both sides of the first circumferential flange 112, moving along the first guide surface 111 and the second guide surface 113 respectively. This causes the fuel jet ejected from the first nozzle 210 to break up and atomize, reducing the central concentration of the fuel jet ejected from the first nozzle 210. One strand of the fuel jet ejected from the first nozzle 210 moves along the first guide surface 111 towards the bottom of the combustion chamber recess 100 and along the center... The protrusion 120 changes direction and, after contacting the ejection protrusion 130, changes direction again to move towards the top of the combustion chamber recess 100. Another stream moves along the second guide surface 113 towards the top of the combustion chamber recess 100, thereby forming a fuel jet that diffuses into the upper and lower regions of the combustion chamber. At the same time, the fuel jet ejected from the second nozzle 220, after hitting the ejection protrusion 130, changes direction to move towards the top of the combustion chamber recess 100, thus achieving the diffusion of the mixture into the region near the nozzle of the fuel injector 200.

[0041] It can be seen that by setting a projectile protrusion 130 on the central protrusion 120 of the piston combustion chamber recess 100, the above-mentioned combustion system can promote the diffusion of the air-fuel mixture to the upper region of the combustion chamber, the lower region of the combustion chamber, and the region near the nozzle of the fuel injector 200, thereby improving the space utilization near the nozzle of the fuel injector 200 and the uniformity of the air-fuel mixture distribution in the entire combustion chamber, improving the combustion quality, and thus improving engine performance.

[0042] It is foreseeable that if the fuel injection amount of the second nozzle 220 is too large, when the fuel jet ejected from the second nozzle 220 and the air-fuel mixture diffuse into the upper region of the combustion chamber, it is easy to interfere with the fuel jet ejected from the first nozzle 210. Therefore, in one embodiment of this application, the aperture of the second nozzle 220 is smaller than the aperture of the first nozzle 210, so that the fuel injection amount of the second nozzle 220 is smaller than the fuel injection amount of the first nozzle 210.

[0043] The above method avoids interference between the fuel jets ejected from the first nozzle 210 and the second nozzle 220 by controlling the amount of fuel injected from the first nozzle 210 and the second nozzle 220. In other embodiments, other methods can be used to achieve this. For example, the first nozzles 210 and the second nozzles 220 can be staggered in the circumferential direction to spatially separate the fuel jets ejected from the first nozzles 210 and the second nozzles 220. Alternatively, the injection timing of the first nozzles 210 and the second nozzles 220 can be staggered to temporally separate the fuel jets ejected from the first nozzles 210 and the second nozzles 220. It should be noted that the above-mentioned control of the fuel injection quantity, injection position setting, and injection timing setting of the first nozzles 210 and the second nozzles 220 can be used individually or at least two of them can be used simultaneously.

[0044] To better control the injection of the first nozzle 210 and the second nozzle 220, and to enable the first nozzle 210 and the second nozzle 220 to inject as needed, the fuel injector 200 in this embodiment includes a first needle valve for controlling the injection of the first nozzle 210 and a second needle valve for controlling the injection of the second nozzle 220. By having the first nozzle 210 and the second nozzle 220 controlled by different needle valves, the injection quantity, injection duration and injection advance angle of different nozzles can be controlled separately, further improving the control accuracy.

[0045] Further optimize the above technical solutions, such as Figure 2 As shown, in one embodiment of this application, the injection cone angle of the first nozzle 210 is greater than that of the second nozzle 220. The injection cone angle refers to the angle between the axis of the nozzle and the axis of the fuel injector 200. By making the injection cone angle of the first nozzle 210 greater than that of the second nozzle 220, the interference between the fuel jet ejected from the first nozzle 210 and the fuel jet ejected from the second nozzle 220 can be further avoided, which facilitates the diffusion of the formed mixture in the combustion chamber.

[0046] The surface of the ejector protrusion 130 facing the second nozzle 220 is the first ejector surface 131, and the surface facing away from the second nozzle 220 is the second ejector surface 132. The ends of the first ejector surface 131 and the second ejector surface 132 away from the central protrusion 120 are smoothly connected by a transition surface 133. The first ejector surface 131 and the second ejector surface 132 are smoothly connected to the circumferential surface of the central protrusion 120. The first ejector surface 131 is used to obliquely eject the fuel jet ejected from the second nozzle 220 toward the top of the combustion chamber pit 100 in a direction away from the central protrusion 120. The second ejector surface 132 is used to obliquely eject a portion of the fuel jet ejected from the first nozzle 210 that moves toward the bottom of the combustion chamber pit 100 toward the top of the combustion chamber pit 100 in a direction away from the central protrusion 120.

[0047] Please continue reading. Figure 2The plane passing through the piston axis is taken as the central symmetry plane of the piston. The intersection of the central symmetry plane and the ejector boss 130 is the ejector boss 130 profile line. The intersection of the central symmetry plane and the central boss 120 is the central boss 120 profile line. The ejector boss 130 profile line includes a first ejection profile line facing the second nozzle 220 and a second ejection profile line facing away from the second nozzle 220. The first ejection profile line is the intersection of the first ejection surface 131 and the central symmetry plane, and the second ejection profile line is the intersection of the second ejection surface 131 and the central symmetry plane. 2. The intersection line with the central symmetry plane, the first end of the first projectile profile and the first end of the second projectile profile are smoothly connected to the central boss 120 profile to avoid stress concentration and reduce the impact on the kinetic energy of the mixture. The second end of the first projectile profile and the second end of the second projectile profile are smoothly connected. The distance between the first projectile profile and the second projectile profile decreases as the distance from the central boss 120 profile increases, further reducing the impact of the projectile boss 130 on the kinetic energy of the mixture.

[0048] As a preferred option, such as Figure 3 As shown, in one embodiment of this application, the first projectile profile is a straight segment or an arc segment concave towards the second projectile profile, and the second projectile profile is a straight segment or an arc segment concave towards the first projectile profile.

[0049] Please continue reading. Figure 3 In one embodiment of this application, the central boss 120 profile includes two circumferential surface profiles and a top surface profile that smoothly connects the two circumferential surface profiles. The circumferential surface profiles include a first surface profile and a second surface profile distributed on both sides of the projectile boss 130 profile. That is, the intersection of the first boss surface 121 and the central symmetry plane is the first surface profile, the intersection of the second boss surface 122 and the central symmetry plane is the second surface profile, and the intersection of the top curved surface 123 of the central boss 120 and the central symmetry plane is the top surface profile. The first surface profile is a straight line segment or an arc segment concave towards the piston axis, the second surface profile is a straight line segment or an arc segment concave towards the piston axis, and the top surface profile is an arc segment concave towards the fuel injector 200.

[0050] It should be noted, of course, that the first surface profile and the second surface profile can also be arc segments that are concave in the circumferential direction away from the piston, and this is not limited here.

[0051] Please see Figure 3The intersection line between the central symmetry plane and the circumferential surface 110 of the combustion chamber recess 100 includes a first guide profile, a first circumferential flange 112 profile, and a second guide profile connected in sequence. The first guide profile is the intersection line between the first guide surface 111 and the central symmetry plane, the second guide profile is the intersection line between the second guide surface 113 and the central symmetry plane, and the first circumferential flange 112 profile is the intersection line between the first circumferential flange 112 and the central symmetry plane. The first guide profile, the first circumferential flange 112 profile, and the second guide profile are smoothly connected in sequence along the direction from the bottom of the combustion chamber recess 100 to the top of the piston. The end of the first guide profile away from the first circumferential flange 112 profile is smoothly connected to the central boss 120 profile to reduce the flow resistance to the mixture.

[0052] Further optimize the above technical solutions, such as Figure 3 As shown, the first guide profile is an arc segment that is concave in the direction away from the piston axis. The first guide profile can be composed of one arc segment or multiple arc segments smoothly connected. The first circumferential flange 112 profile is an arc segment that is concave in the direction of the piston axis. The first circumferential flange 112 profile can be composed of one arc segment or multiple arc segments smoothly connected. The second guide profile is a straight line segment that slopes away from the piston axis from the end connected to the first circumferential flange 112 profile, or an arc segment that is concave in the direction away from the piston axis. Alternatively, the second guide profile can be composed of at least one straight line segment and at least one arc segment smoothly connected. The second guide profile can also be composed of multiple arc segments smoothly connected.

[0053] Please see Figure 1 and Figure 3 In one embodiment of this application, in order to provide a second circumferential flange 114 on the circumferential surface 110 of the combustion chamber recess 100, the intersection line of the second circumferential flange 114 and the central symmetry plane is the second circumferential flange 114 profile. The second circumferential flange 114 profile is an arc segment recessed in the direction of the piston axis. One end of the second circumferential flange 114 profile is smoothly connected to the second guide profile, and the other end is connected to the top surface profile formed by the intersection of the piston top surface and the central symmetry plane. The second circumferential flange 114 can further guide and propel the mixture, so that the mixture diffuses to the upper region of the combustion chamber.

[0054] This application also provides an internal combustion engine, which includes the combustion system described in the above embodiments. The internal combustion engine includes, but is not limited to, a diesel engine. Since the internal combustion engine uses the combustion system described in the above embodiments, the technical effects of the internal combustion engine can be referred to the above embodiments.

[0055] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0056] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0057] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0058] This article uses specific examples to illustrate the principles and implementation methods of this utility model. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made to this utility model without departing from the principles of this utility model, and these improvements and modifications also fall within the protection scope of the claims of this utility model.

Claims

1. A combustion system, characterized in that, include: The piston has a combustion chamber recess (100) on its top, and a first circumferential flange (112) is provided on the circumferential surface (110) of the combustion chamber recess (100). A central boss (120) protruding towards the bottom surface of the cylinder head of the combustion system is provided at the bottom of the combustion chamber recess (100), and a projectile boss (130) is provided on the circumferential surface of the central boss (120). A fuel injector (200) is disposed on the cylinder head. The fuel injector (200) is provided with a plurality of first nozzles (210) and a plurality of second nozzles (220) in the circumferential direction. In the axial direction of the fuel injector (200), the second nozzles (220) are farther away from the cylinder head than the first nozzles (210). The first nozzles (210) face the first circumferential flange (112), and the second nozzles (220) face the ejection boss (130).

2. The combustion system according to claim 1, characterized in that, The diameter of the second nozzle (220) is smaller than the diameter of the first nozzle (210).

3. The combustion system according to claim 1, characterized in that, The spray cone angle of the first nozzle (210) is greater than that of the second nozzle (220).

4. The combustion system according to any one of claims 1-3, characterized in that, The plane passing through the piston axis is the central symmetry plane of the piston. The intersection of the central symmetry plane and the projectile boss (130) is the projectile boss (130) profile. The intersection of the central symmetry plane and the central boss (120) is the central boss (120) profile. The projectile boss (130) profile includes a first projectile profile facing the second nozzle (220) and a second projectile profile facing away from the second nozzle (220). The first end of the first projectile profile and the first end of the second projectile profile are smoothly connected to the central boss (120) profile. The second end of the first projectile profile and the second end of the second projectile profile are smoothly connected. The distance between the first projectile profile and the second projectile profile decreases as the distance from the central boss (120) profile increases.

5. The combustion system according to claim 4, characterized in that, The first projectile profile is a straight line segment or an arc segment that is concave towards the direction of the second projectile profile, and the second projectile profile is a straight line segment or an arc segment that is concave towards the direction of the first projectile profile.

6. The combustion system according to claim 4, characterized in that, The central boss (120) profile includes two circumferential surface profiles and a top surface profile that smoothly connects the two circumferential surface profiles. The circumferential surface profiles include a first surface profile and a second surface profile distributed on both sides of the projectile boss (130) profile. The first surface profile is a straight line segment or an arc segment recessed towards the axis of the piston. The second surface profile is a straight line segment or an arc segment recessed towards the axis of the piston.

7. The combustion system according to claim 4, characterized in that, The intersection of the central symmetry plane and the circumferential surface (110) of the combustion chamber recess (100) includes a first guide line, a first circumferential flange (112) line and a second guide line connected in sequence. The first guide line, the first circumferential flange (112) line and the second guide line are smoothly connected in sequence from the bottom of the combustion chamber recess (100) to the top of the piston. The end of the first guide line away from the first circumferential flange (112) line is smoothly connected to the central boss (120) line.

8. The combustion system according to claim 7, characterized in that, The first guide profile is an arc segment that is concave in the direction away from the axis of the piston, the first circumferential flange (112) profile is an arc segment that is concave in the direction of the axis of the piston, and the second guide profile is a straight line segment or an arc segment that is concave in the direction away from the axis of the piston, starting from the end connected to the first circumferential flange (112) profile.

9. The combustion system according to claim 7, characterized in that, The circumferential surface (110) of the combustion chamber recess (100) is provided with a second circumferential flange (114). The intersection of the second circumferential flange (114) and the central symmetry plane is the second circumferential flange (114) profile. The second circumferential flange (114) profile is an arc segment recessed towards the axis of the piston. One end of the second circumferential flange (114) profile is smoothly connected to the second guide profile, and the other end is connected to the top surface profile formed by the intersection of the top surface of the piston and the central symmetry plane.

10. An internal combustion engine, characterized in that, Includes the combustion system as described in any one of claims 1-9.

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