A piston, combustion system and internal combustion engine

Abstract

The present application relates to a kind of piston, combustion system and internal combustion engine, the top of the piston is provided with combustion chamber pit, the circumferential wall surface of combustion chamber pit is sequentially provided with first flow guide surface and second flow guide surface along the bottom surface of combustion chamber pit to the direction of the top of piston, first flow guide surface and second flow guide surface are smoothly connected to form the first circumferential flange projecting to the direction of the injection hole of fuel injector between first flow guide surface and second flow guide surface, the circumferential wall surface of combustion chamber pit is spaced apart along circumference and is provided with multiple radial flange projecting to the direction of the injection hole of fuel injector, the lower end of radial flange extends to the bottom surface of combustion chamber pit, and the upper end extends to second flow guide surface, the part of radial flange on first circumferential flange is arranged opposite to the injection hole of fuel injector one by one.The radial flange of the above-mentioned piston cooperates with circumferential flange to make fuel jet respectively dispersed to four directions, can form four swirl zones of fuel jet, improve gas mixing speed and heat release rate peak, improve combustion efficiency, and then improve engine thermal efficiency.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of internal combustion engines, in particular to a piston, a combustion system and an internal combustion engine. BACKGROUND

[0002] The engine national emission regulations are increasingly stringent, and higher requirements are put forward for engine thermal efficiency. The compression ratio of diesel engine is relatively high, and at the same time, it has high fuel injection pressure and in-cylinder explosion pressure, so it is particularly important to reasonably organize the mixing of high-pressure diesel and fresh air. If diesel and air are not mixed uniformly, it will cause low air utilization rate of the combustion chamber, insufficient fuel combustion, poor combustion effect, increased smoke generated during the combustion process, increased fuel consumption rate and poor combustion economy. The engine piston and fuel injector are key components of the combustion system, and the advantages and disadvantages of the combustion system composed of the engine piston and the fuel injector are particularly important for the organization of the combustion process. A reasonable combustion system is beneficial to improve the air utilization rate of the combustion chamber and reduce the oil consumption of the engine.

[0003] As shown in Figure 1 At present, a piston with a combustion chamber pit at the top is usually used, and a circumferential flange (also known as a throat) protruding towards the direction of the injection hole of the oil injector is arranged on the circumferential side wall of the combustion chamber pit of the piston. The high-pressure fuel injected by the oil injector forms a relatively thick mixture with fresh air, and after reaching the circumferential flange position, part of the mixture diffuses upwards under the diversion of the circumferential flange, and the remaining mixture diffuses to the bottom of the combustion chamber pit below the circumferential flange, and then is sucked upwards after reaching the bottom of the combustion chamber pit. However, this combustion chamber pit structure causes the oil jet to be divided only at the throat position, and almost spreads on the surface of the combustion chamber pit. The center of the oil jet is mixed slowly, there is an over-concentration area, the oil-gas mixing effect is limited, it is difficult to further promote the mixing, resulting in low engine thermal efficiency. Especially for high-power engines, the center of the oil jet is thicker, and it is more difficult to mix uniformly. SUMMARY

[0004] The first object of the present application is to provide a piston to improve the mixing speed of the fuel jet center and improve the gas mixing effect.

[0005] The second object of the present application is to provide a combustion system and an internal combustion engine comprising the above-mentioned piston.

[0006] To achieve the above-mentioned objects, the present application provides the following technical solutions:

[0007] In a first aspect, the application provides a piston, a combustion chamber pit is arranged on a top of the piston, a circumferential wall surface of the combustion chamber pit is sequentially provided with a first flow guide surface and a second flow guide surface in a direction from a bottom surface of the combustion chamber pit to a top surface of the piston, the first flow guide surface is recessed in a direction away from an axis of the piston, the second flow guide surface is recessed in a direction away from a bottom surface of a cylinder head, a first circumferential flange protruding in a direction of a nozzle of a fuel injector is formed by a smooth transition connection between the first flow guide surface and the second flow guide surface, a plurality of radial flanges protruding in the direction of the nozzle of the fuel injector are arranged on the circumferential wall surface of the combustion chamber pit at intervals in a circumferential direction, the radial flanges correspond one-to-one to the nozzles of the fuel injector, lower ends of the radial flanges extend to the bottom surface of the combustion chamber pit, upper ends of the radial flanges extend to the second flow guide surface, and portions of the radial flanges located on the first circumferential flange are arranged opposite the nozzles of the fuel injector.

[0008] In a possible implementation, the radial flanges are symmetrically arranged about a radial plane of the piston.

[0009] In a possible implementation, the radial flange includes a first flange portion, a second flange portion, and a third flange portion sequentially connected in a direction from the bottom surface of the combustion chamber pit to the top surface of the piston, the second flange portion is located on a surface of the first circumferential flange, a circumferential dimension of the second flange portion is greater than circumferential dimensions of the first flange portion and the third flange portion, and the second flange portion is arranged opposite the nozzle of the fuel injector.

[0010] In a possible implementation, surfaces of the first flange portion, the second flange portion, and the third flange portion are all smooth curved surfaces, a smooth curved surface radius r1 of the first flange portion, a smooth curved surface radius r2 of the second flange portion, and a smooth curved surface radius r3 of the third flange portion satisfy r1 < r2 < r3.

[0011] In a possible implementation, a surface of the first circumferential flange is a smooth curved surface, a smooth curved surface radius r4 of the first circumferential flange and the smooth curved surface radius r2 of the second flange portion satisfy r2 ≤ r4.

[0012] In a possible implementation, in the direction from the bottom surface of the combustion chamber pit to the top surface of the piston, a circumferential dimension of the first flange portion gradually increases, and / or a circumferential dimension of the third flange portion gradually increases.

[0013] In a possible implementation, the radial flange comprises first radial flanges and second radial flanges, the first radial flanges and the second radial flanges are alternately arranged along the circumference of the combustion chamber pit, the first radial flanges are arranged one-to-one with the first injection holes on the fuel injector, the second radial flanges are arranged one-to-one with the second injection holes on the fuel injector, and the ratio of the volume of the first radial flange to the volume of the second radial flange is equal to the ratio of the fuel injection amount of the first injection hole to the fuel injection amount of the second injection hole.

[0014] In a possible implementation, the circumferential side wall of the combustion chamber pit further comprises a third flow guide surface arranged between the second flow guide surface and the top surface of the piston, and the second flow guide surface and the third flow guide surface are connected in a smooth transition to form a second circumferential flange protruding in the direction of the bottom surface of the cylinder head or the injection hole of the fuel injector, the radial distance between the first circumferential flange, the second circumferential flange, the upper edge of the circumferential wall of the combustion chamber pit, and the axis of the piston increases in turn, and the third flow guide surface is recessed away from the bottom surface of the cylinder head.

[0015] In a possible implementation, the circumferential wall of the combustion chamber pit further comprises a fourth flow guide surface, the third flow guide surface is connected to the top surface of the piston through the fourth flow guide surface, and the fourth flow guide surface protrudes in the direction of the bottom surface of the cylinder head.

[0016] In a possible implementation, the bottom of the combustion chamber pit is provided with a central boss protruding in the direction of the bottom surface of the cylinder head, the circumferential wall of the combustion chamber pit is arranged around the central boss, and the bottom of the surface of the central boss is connected in a smooth transition to the first flow guide surface.

[0017] In a possible implementation, the surface of the central boss comprises a fifth flow guide surface, a flow guide slope, and a sixth flow guide surface, the fifth flow guide surface is located at the top of the central boss, the fifth flow guide surface is connected in a smooth transition to the sixth flow guide surface through the flow guide slope, the sixth flow guide surface is connected in a smooth transition to the first flow guide surface, and the diameter of the flow guide slope gradually increases in the direction from the fifth flow guide surface to the sixth flow guide surface.

[0018] It can be seen from the above technical solutions that the piston disclosed in the present application is provided with a combustion chamber pit at the top of the piston, a first flow guide surface and a second flow guide surface are sequentially arranged on the circumferential wall surface of the combustion chamber pit in the direction from the bottom surface of the combustion chamber pit to the top surface of the piston, the first flow guide surface is recessed in the direction away from the axis of the piston, the second flow guide surface is recessed in the direction away from the bottom surface of the cylinder head, the first flow guide surface and the second flow guide surface are smoothly connected to form a first circumferential flange protruding in the direction of the injection hole of the fuel injector, a plurality of radial flanges protruding in the direction of the injection hole of the fuel injector are arranged on the circumferential wall surface of the combustion chamber pit at intervals in the circumferential direction, the radial flanges correspond to the injection holes of the fuel injector one by one, the lower end of the radial flange extends to the bottom surface of the combustion chamber pit, and the upper end extends to the second flow guide surface, and the part of the radial flange located on the first circumferential flange is arranged opposite to the injection hole of the fuel injector.

[0019] The radial flange is arranged on the circumferential side wall of the combustion chamber pit of the piston, and forms a cross structure with the first circumferential flange. In the application process, the fuel spray hits the cross structure, and the radial flange and the first circumferential flange cooperate to scatter the oil beam in the horizontal and vertical directions respectively in two directions, so that the fuel spray is more easily broken and atomized, the central concentration of the fuel spray is reduced, the fuel spray is dispersed in four directions respectively, and the flow guide of the first flow guide surface and the second flow guide surface to the fuel spray can form four different direction vortex zones of the fuel spray, improve the gas mixing speed, improve the heat release rate peak, and significantly improve the combustion efficiency, thereby improving the thermal efficiency of the engine.

[0020] In a second aspect of the present application, a combustion system is provided, comprising:

[0021] a piston, which is the piston as described in the first aspect and possible implementation manners thereof;

[0022] a fuel injector arranged on the cylinder head of the combustion system, a plurality of injection holes are arranged on the fuel injector in the circumferential direction, the injection holes are arranged one by one corresponding to the radial flanges in the combustion chamber pit of the piston, and the injection holes are arranged towards the part of the radial flange located on the first circumferential flange of the piston.

[0023] In a possible implementation manner, the injection holes include first injection holes and second injection holes, a plurality of the first injection holes and a plurality of the second injection holes are arranged alternately and at intervals in the circumferential direction of the fuel injector, and the first injection holes and the second injection holes are arranged staggered in the axial direction of the fuel injector, the radial flanges include first radial flanges arranged one by one corresponding to the first injection holes and second radial flanges arranged one by one corresponding to the second injection holes.

[0024] In a possible implementation, a ratio of a volume of the first radial flange to a volume of the second radial flange is equal to a ratio of a fuel injection amount of the first injection hole to a fuel injection amount of the second injection hole.

[0025] Since the combustion system described above adopts the piston in the first aspect and possible implementation ways, the combustion system should have the same beneficial effects as the piston, which will not be repeated here.

[0026] In the third aspect of the present application, the present application provides an internal combustion engine comprising the combustion system as described in the second aspect and possible implementation ways above.

[0027] Since the internal combustion engine adopts the combustion system in the second aspect and possible implementation ways, the internal combustion engine should have the same beneficial effects as the combustion system, which will not be repeated here. BRIEF DESCRIPTION OF DRAWINGS

[0028] 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 prior art description. Obviously, the drawings in the following description only constitute some embodiments of the present application, and for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0029] Figure 1 It is a partial cross-sectional view of the piston in the prior art;

[0030] Figure 2 It is a partial structure schematic view of the piston provided by the embodiment of the present application;

[0031] Figure 3 It is a top view of the piston provided by the embodiment of the present application;

[0032] Figure 4 It is a partial enlarged schematic view of the piston provided by the embodiment of the present application;

[0033] Figure 5 It is a structure schematic view of the combustion chamber pit of the piston provided by the embodiment of the present application;

[0034] Figure 6 It is a structure schematic view of the fuel injector provided by the embodiment of the present application;

[0035] Figure 7 It is a design parameter schematic view of the fuel injector provided by the embodiment of the present application.

[0036] Figure 1 In the middle:

[0037] 01 is a piston; 02 is a combustion chamber pit; 03 is a circumferential flange;

[0038] Figures 2 to 7 In one aspect of the present application, a piston is provided.

[0039] 100 is a piston; 200 is a combustion chamber recess; 210 is a first flow guide surface; 220 is a second flow guide surface; 230 is a third flow guide surface; 240 is a fourth flow guide surface; 300 is a first circumferential flange; 400 is a radial flange; 410 is a first flange portion; 420 is a second flange portion; 430 is a third flange portion; 400a is a first radial flange; 400b is a second radial flange; 500 is a top surface; 600 is a second circumferential flange; 700 is a central boss; 710 is a fifth flow guide surface; 720 is a flow guide slope surface; 730 is a sixth flow guide surface; 800 is a fuel injector; 810 is a first injection hole; 820 is a second injection hole. DETAILED DESCRIPTION

[0040] One of the cores of the present application is to provide a piston which is designed to improve the mixing speed of the fuel jet center and improve the gas mixing effect.

[0041] Another core of the present application is to provide a combustion system comprising the above piston and an internal combustion engine.

[0042] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the scope of protection of the present application.

[0043] To improve the poor dispersion effect of the combustion chamber recess of the current piston on the fuel jet, the present application provides a piston 100, please refer to Figures 2 to 4 .

[0044] The piston 100 is provided with a combustion chamber recess 200 on the top. The circumferential wall surface of the combustion chamber recess 200 is sequentially provided with a first flow guide surface 210 and a second flow guide surface 220 in the direction from the bottom surface of the combustion chamber recess 200 to the top surface 500 of the piston 100. Of course, it should be noted that the circumferential wall surface of the combustion chamber recess 200 can only be composed of the first flow guide surface 210 and the second flow guide surface 220, or other flow guide surfaces can be added on this basis, which is not limited here.

[0045] To reduce the resistance to the fuel jet and the mixture of the fuel jet and air, the first flow guide surface 210 and the second flow guide surface 220 are smooth curved surfaces or a combination of smooth curved surfaces and flat surfaces. The first flow guide surface 210 and the second flow guide surface 220 are both revolving curved surfaces which surround the axis of the piston 100 and are closed in the circumferential direction.

[0046] The first flow guide surface 210 is recessed away from the axis of the piston 100, and the second flow guide surface 220 is recessed away from the bottom surface of the cylinder head. The first flow guide surface 210 and the second flow guide surface 220 are connected in a smooth transition to form a first circumferential flange 300 protruding towards the injection hole of the fuel injector 800. The first circumferential flange 300 is closer to the axis of the piston 100 than the upper edge of the circumferential wall surface of the combustion chamber pit 200, and the injection hole of the fuel injector 800 in the combustion system also faces the first circumferential flange 300. The first circumferential flange 300 is a revolving curved surface surrounding the axis of the piston 100 and closed in the circumferential direction. Thus, the fuel jet forms two air flows upward and downward along the first flow guide surface 210 and the second flow guide surface 220 after hitting the first circumferential flange 300.

[0047] The circumferential wall surface of the combustion chamber pit 200 is provided with a plurality of radial flanges 400 protruding towards the injection hole of the fuel injector 800 at intervals in the circumferential direction. The radial flanges 400 correspond one-to-one to the injection holes of the fuel injector 800, i.e., the number of radial flanges 400 is exactly the same as the number of injection holes of the fuel injector 800. The lower end of the radial flange 400 extends to the bottom surface of the combustion chamber pit 200, and the upper end extends to the second flow guide surface 220, i.e., the radial flange 400 extends from the bottom surface of the combustion chamber pit 200 to the second flow guide surface 220 in the radial direction of the piston 100. The part of the radial flange 400 on the first circumferential flange 300 is arranged opposite the injection hole of the fuel injector 800.

[0048] It should be noted that the radial flange 400 can be divided into two parts by the first circumferential flange 300, i.e., the height of the radial flange 400 is the same as or slightly lower than the height of the first circumferential flange 300. Alternatively, the height of the radial flange 400 can be greater than the height of the first circumferential flange 300, or the height of the part where the radial flange 400 intersects the first circumferential flange 300 is greater than the height of the first circumferential flange 300, and the height of the remaining part is the same as or slightly less than the height of the first circumferential flange 300, i.e., the part where the radial flange 400 intersects the first circumferential flange 300 protrudes outward from the surface of the first circumferential flange 300. The height of the radial flange 400 and the first circumferential flange 300 mentioned above refers to the vertical distance between the top of the radial flange 400 or the first circumferential flange 300 away from the circumferential surface of the combustion chamber pit 200 and the circumferential surface of the combustion chamber pit 200.

[0049] In summary, the piston 100 provided by the embodiment of the application has the radial flange 400 arranged on the circumferential side wall of the combustion chamber pit 200 at the top of the piston 100, which forms a cross structure with the first circumferential flange 300. In the application process, the fuel spray impinges on the cross structure, and the radial flange 400 cooperates with the first circumferential flange 300 to scatter the fuel spray in the horizontal and vertical directions respectively to two directions, so that the fuel spray is more easily broken and atomized, the fuel spray center concentration is reduced, the fuel spray is dispersed in four directions respectively, and the fuel spray is guided by the first flow guide surface 210 and the second flow guide surface 220, so that four entrainment zones of the fuel spray in different directions are formed, the gas mixing speed is improved, the heat release rate peak is improved, the combustion efficiency is significantly improved, and the engine thermal efficiency is improved.

[0050] In order to make the fuel spray more evenly dispersed after impinging on the radial flange 400, in one embodiment of the application, as shown in Figures 2 to 4 , the radial flange 400 is arranged symmetrically about the radial plane of the piston 100, so that the fuel spray can be symmetrically and evenly dispersed to the radial flange 400 after impinging on the radial flange 400, and the uniformity of fuel distribution on both sides of the radial flange 400 is ensured.

[0051] Of course, it should be noted that the radial flange 400 cannot be completely symmetrical in the actual processing and manufacturing process, and the radial flange 400 is not completely symmetrical on both sides of the radial plane of the piston 100 due to process errors and human errors, which also belongs to the protection scope of the scheme. In addition, the radial flange 400 can also be arranged asymmetrically about the radial plane of the piston 100, so that the fuel spray is asymmetrically dispersed after impinging on the radial flange 400.

[0052] As shown in Figure 4 , the radial flange 400 includes the first flange part 410, the second flange part 420 and the third flange part 430 connected in sequence from the bottom surface of the combustion chamber pit 200 to the top surface 500 of the piston 100, the second flange part 420 is located on the surface of the first circumferential flange 300, the first flange part 410 is located on the first flow guide surface 210 or is located on the first flow guide surface 210 and the end of the first flange part 410 away from the second flange part 420 exceeds the edge of the first flow guide surface 210 and extends around the center of the combustion chamber pit 200, the third flange part 430 is located on the second flow guide surface 220, the circumferential dimension of the second flange part 420 is greater than the circumferential dimensions of the first flange part 410 and the third flange part 430, and the second flange part 420 is arranged opposite to the injection hole of the fuel injector 800, that is, the fuel spray impinges on the second flange part 420.

[0053] To reduce the flow resistance of the fuel jet during dispersion along the radial flange 400, in an embodiment of the present application, the surface of the first flange portion 410, the second flange portion 420 and the third flange portion 430 is a smooth curve, including but not limited to a circular arc surface, a spherical surface, and the first flange portion 410, the second flange portion 420 and the third flange portion 430 are smoothly connected with the circumferential side wall of the combustion chamber pit 200, and the first flange portion 410 and the second flange portion 420 and the second flange portion 420 and the third flange portion 430 are smoothly connected, to reduce stress concentration, the smooth curve radius r1 of the first flange portion 410, the smooth curve radius r2 of the second flange portion 420 and the smooth curve radius r3 of the third flange portion 430 satisfy r1 < r2 < r3, as shown in Figure 4

[0054] Further, in a preferred embodiment of the present application, the surface of the first circumferential flange 300 is a smooth curve, and the smooth curve radius r4 of the first circumferential flange 300 and the smooth curve radius r2 of the second flange portion 420 satisfy r2 ≤ r4, so that the second flange portion 420 can protrude significantly from the first circumferential flange 300, improving the impact dispersion effect on the fuel jet.

[0055] The circumferential size of the first flange portion 410 in the extension direction of the radial flange 400 can be uniform without change, that is, the first flange portion 410 is uniformly provided with equal width in the extension direction of the radial flange 400, or the circumferential size of the first flange portion 410 in the extension direction of the radial flange 400 can be provided with unequal width, that is, the width of the first flange portion 410 gradually increases in the extension direction of the radial flange 400, or first widened and then narrowed, or first narrowed and then widened. Similarly, the circumferential size of the third flange portion 430 in the extension direction of the radial flange 400 can be uniform without change, that is, the third flange portion 430 is uniformly provided with equal width in the extension direction of the radial flange 400, or the circumferential size of the third flange portion 430 in the extension direction of the radial flange 400 can be provided with unequal width, that is, the width of the first flange portion 410 gradually increases in the extension direction of the radial flange 400, or first widened and then narrowed, or first narrowed and then widened.

[0056] It can be predicted that the circumferential size of the combustion chamber pit 200 gradually increases from the bottom, that is, the gap between the two adjacent radial flanges 400 gradually increases, and therefore in order to make the fuel distribution more uniform, in an embodiment of the present application, the circumferential size of the first flange portion 410 gradually increases in the direction from the bottom surface of the combustion chamber pit 200 to the top surface 500 of the piston 100, and / or the circumferential size of the third flange portion 430 gradually increases, that is, the circumferential size of at least one of the first flange portion 410 and the third flange portion 430 gradually increases in the direction from the bottom surface of the combustion chamber pit 200 to the top surface 500 of the piston 100.​

[0057] like Figure 4 As shown, in a specific embodiment of the present application, the circumferential dimension of the first flange portion 410 gradually increases along the direction from the bottom surface of the combustion chamber recess 200 to the top surface 500 of the piston 100, and the circumferential dimension of the third flange portion 430 gradually increases, and the circumferential dimension of one end where the first flange portion 410 is connected to the second flange portion 420 is the same as or similar to the circumferential dimension of one end where the third flange portion 430 is connected to the second flange portion 420.

[0058] It should be noted that the parameters of each nozzle of the fuel injector 800 can be exactly the same, that is, the parameters such as the diameter, injection cone angle and axial position of each nozzle are completely consistent. In this case, the fuel injection amount of each nozzle is exactly the same, so the radial flange 400 in each combustion chamber pit 200 can adopt exactly the same structure and size.

[0059] However, in some cases, the fuel injector 800 includes two groups of nozzle holes. The two groups of nozzle holes have different parameters such as diameter, injection cone angle and axial position. Therefore, the fuel injection amounts are different. The different fuel injection amounts also have different requirements for the dispersion effect. Therefore, in order to be able to adapt to the above-mentioned nozzle holes with different fuel injection amounts, in one embodiment of the present application, the radial flange 400 includes a first radial flange 400a and a second radial flange 400b. The multiple first radial flanges 400a and the multiple second radial flanges 400b are alternately arranged along the circumference of the combustion chamber pit 200. The first radial flange 400a is arranged in a one-to-one correspondence with the first nozzle hole 810 on the fuel injector 800, and the second radial flange 400b is arranged in a one-to-one correspondence with the second nozzle hole 820 on the fuel injector 800. The ratio of the volume of the first radial flange 400a to the volume of the second radial flange 400b is equal to the ratio of the fuel injection amount of the first nozzle hole 810 to the fuel injection amount of the second nozzle hole 820, that is, the volume of the radial flange 400 corresponding to the nozzle with a large fuel injection amount is also correspondingly large, and the volume of the radial flange 400 corresponding to the nozzle with a small fuel injection amount is also correspondingly small.

[0060] It can be foreseen that if there is a drop and / or different injection cone angles between the first nozzle 810 and the second nozzle 820 in the axial direction of the fuel injector 800, the landing point of the fuel spray beam on the circumferential side wall of the combustion chamber pit 200 will also be different. Accordingly, it is necessary to adjust the position of the second flange portion 420 of the first radial flange 400a and the second radial flange 400b on the first circumferential flange 300. For example, the second flange portion 420 can be appropriately set on the side of the first circumferential flange 300 close to the second guide surface 220 or on the side of the first circumferential flange 300 close to the first guide surface 210.

[0061] For example, in the present application, the fuel injection amount of the first injection hole 810 is greater than that of the second injection hole 820, the volume of the first radial flange 400a is greater than that of the second radial flange 400b, and accordingly, the radius r1 of the first flange portion 410 of the first radial flange 400a is 0.5mm~1mm, the radius r2 of the second flange portion 420 is equal to the radius r4 of the first circumferential flange 300, i.e. r2=r4, the radius r3 of the third flange portion 430 is 5mm~6mm, the radius r1' of the first flange portion 410 of the second radial flange 400b is 0.5mm~1mm, the radius r2' of the second flange portion 420 is 0.6 times~0.9 times of the radius r4 of the first circumferential flange 300, i.e. r2'=(0.6~0.9)r4, and the radius r3' of the third flange portion 430 is 3mm~5mm.

[0062] Referring to Figures 2 to 5 In an embodiment of the present application, the circumferential side wall of the combustion chamber pit 200 further comprises a third flow guide surface 230 arranged between the second flow guide surface 220 and the top surface 500 of the piston 100, and the second flow guide surface 220 and the third flow guide surface 230 are smoothly connected to form a second circumferential flange 600 protruding towards the direction of the injection hole of the fuel injector 800, the radial distance between the first circumferential flange 300, the second circumferential flange 600, the upper edge of the circumferential wall of the combustion chamber pit 200 and the axis of the piston 100 increases in turn, and the third flow guide surface 230 is recessed away from the bottom surface of the cylinder head.

[0063] Further, as Figure 5 shown, the circumferential wall of the combustion chamber pit 200 further comprises a fourth flow guide surface 240, the third flow guide surface 230 is connected to the top surface 500 of the piston 100 through the fourth flow guide surface 240, the fourth flow guide surface 240 protrudes towards the bottom surface of the cylinder head, the third flow guide surface 230 and the top surface 500 of the piston 100 are smoothly connected through the fourth flow guide surface 240, and the third flow guide surface 230 and the fourth flow guide surface 240 form an annular groove between the combustion chamber pit 200 and the top surface 500 of the piston 100.

[0064] When the fuel jet moves along the second guide surface 220 to the second circumferential flange 600, the fuel jet forms a jet in the upper area of the annular groove under the guide and projection of the second circumferential flange 600. By using the part of the jet and the entrainment effect of the air around the top surface 500 of the piston 100, the uniformity of the gas mixture in the annular groove space can be further improved, which is beneficial to improve the thermal efficiency of the engine. The annular groove forms an air interlayer between the top surface 500 of the piston 100 and the air in the annular groove, which further isolates or reduces the heat conduction of the mixed gas combustion above to the wall surface of the piston 100, reduces the heat transfer loss of the piston 100, and further improves the thermal efficiency of the engine.

[0065] As shown in Figures 2 to 5 , the bottom of the combustion chamber pit 200 is provided with a central boss 700 protruding towards the bottom surface of the cylinder head, and the circumferential wall of the combustion chamber pit 200 is arranged around the central boss 700. The bottom surface of the central boss 700 is smoothly connected to the first guide surface 210, and the central boss 700 is arranged to make the combustion chamber pit 200 have an ω-shaped structure, which can enhance the tumble flow intensity in the combustion chamber.

[0066] As shown in Figure 5 , the surface of the central boss 700 includes a fifth guide surface 710, a guide slope surface 720, and a sixth guide surface 730. The fifth guide surface 710 is located at the top of the central boss 700 and has a spherical structure. The fifth guide surface 710 is smoothly connected to the sixth guide surface 730 through the guide slope surface 720, and the sixth guide surface 730 is smoothly connected to the first guide surface 210. The diameter of the guide slope surface 720 increases gradually in the direction from the fifth guide surface 710 to the sixth guide surface 730.

[0067] Please refer to Figure 5 , the plane passing through the axis of the piston 100 is the symmetry plane of the piston 100. The intersection line between the inner wall of the combustion chamber pit 200 and the symmetry plane includes: a first guide curve corresponding to the first guide surface 210, a second guide curve corresponding to the second guide surface 220, a third guide curve corresponding to the third guide surface 230, a fourth guide curve corresponding to the fourth guide surface 240, a fifth guide curve corresponding to the first circumferential flange 300, a sixth guide curve corresponding to the second circumferential flange 600, a seventh guide curve corresponding to the fifth guide surface 710, an eighth guide curve corresponding to the guide slope surface 720, and a ninth guide curve corresponding to the sixth guide surface 730. The eighth guide curve is a straight line segment or a circular arc line segment, and the remaining guide curves are circular arc curve segments.

[0068] The seventh guide curve, the eighth guide curve, the ninth guide curve, the first guide curve, the fifth guide curve, the second guide curve, the sixth guide curve, the third guide curve and the fourth guide curve are sequentially and smoothly connected in the direction from the axis of the piston 100 to the outer circumferential surface of the piston 100.

[0069] As shown in the drawings, Figure 5 In a specific embodiment, the radius of the piston 100 is R1, the radius R2 of the combustion chamber pit 200 satisfies R2 = (0.86-0.96)R1, the distance R3 between the center of the fifth guide curve and the axis of the piston 100 satisfies R3 = (0.45-0.55)R1, and the depth H of the combustion chamber pit 200 satisfies H = (0.21-0.29)R1.

[0070] The radius r4 of the fifth guide curve is 2mm-4.5mm, the radius r5 of the first guide curve is (0.04-0.11)R1, the radius r6 of the second guide curve is (0.13-0.19)R1, the radius r7 of the third guide curve is (0.15-0.29)R1, the radius r8 of the sixth guide curve is 1mm-2.5mm, the radius r9 of the fourth guide curve is (0.20-0.35)R1, the radius r10 of the seventh guide curve is (0.22-0.28)R1, and the radius r11 of the ninth guide curve is (0.10-0.16)R1.

[0071] Based on the above-mentioned piston 100, the embodiment of the present application further provides a combustion system, which comprises the piston 100 and a fuel injector 800, wherein the piston 100 is the piston 100 as described in the above-mentioned embodiment, the piston 100 is reciprocally movable, the fuel injector 800 is arranged on the cylinder head of the combustion system, the fuel injector 800 is arranged with a plurality of injection holes in the circumferential direction, the injection holes are arranged one by one corresponding to the radial flanges 400 in the combustion chamber pits 200 of the piston 100, and the injection holes are directed to the part of the radial flanges 400 located on the first circumferential flange 300 of the piston 100. Since the combustion system adopts the piston 100 in the above-mentioned embodiment, the technical effects of the combustion system please refer to the above-mentioned embodiment.

[0072] The diameters, injection cone angles and axial positions of the injection holes of the fuel injector 800 in the combustion system provided by the present application are completely consistent, and the injection holes can also include at least two different design parameters, that is, at least one of the diameters, injection cone angles and axial positions of the two injection holes is different.

[0073] As shown in the drawings, Figure 6As shown in the embodiment of the present application, the injection holes include first injection holes 810 and second injection holes 820, the first injection holes 810 and the second injection holes 820 are alternately and spacedly arranged along the circumference of the fuel injector 800, the number of the first injection holes 810 can be same or different from the number of the second injection holes 820, and the first injection holes 810 and the second injection holes 820 are arranged in axial staggered manner along the fuel injector 800, the radial flange 400 includes first radial flanges 400a corresponding to the first injection holes 810 and second radial flanges 400b corresponding to the second injection holes 820.

[0074] As shown in the embodiment of the present application, the injection holes include first injection holes 810 and second injection holes 820, the first injection holes 810 and the second injection holes 820 are alternately and spacedly arranged along the circumference of the fuel injector 800, the number of the first injection holes 810 can be same or different from the number of the second injection holes 820, and the first injection holes 810 and the second injection holes 820 are arranged in axial staggered manner along the fuel injector 800, the radial flange 400 includes first radial flanges 400a corresponding to the first injection holes 810 and second radial flanges 400b corresponding to the second injection holes 820. Figure 7 As shown in the embodiment of the present application, the injection holes include first injection holes 810 and second injection holes 820, the first injection holes 810 and the second injection holes 820 are alternately and spacedly arranged along the circumference of the fuel injector 800, the number of the first injection holes 810 can be same or different from the number of the second injection holes 820, and the first injection holes 810 and the second injection holes 820 are arranged in axial staggered manner along the fuel injector 800, the radial flange 400 includes first radial flanges 400a corresponding to the first injection holes 810 and second radial flanges 400b corresponding to the second injection holes 820.

[0075] As shown in the embodiment of the present application, the injection holes include first injection holes 810 and second injection holes 820, the first injection holes 810 and the second injection holes 820 are alternately and spacedly arranged along the circumference of the fuel injector 800, the number of the first injection holes 810 can be same or different from the number of the second injection holes 820, and the first injection holes 810 and the second injection holes 820 are arranged in axial staggered manner along the fuel injector 800, the radial flange 400 includes first radial flanges 400a corresponding to the first injection holes 810 and second radial flanges 400b corresponding to the second injection holes 820. 2 2 .

[0076] As shown in the embodiment of the present application, the injection holes include first injection holes 810 and second injection holes 820, the first injection holes 810 and the second injection holes 820 are alternately and spacedly arranged along the circumference of the fuel injector 800, the number of the first injection holes 810 can be same or different from the number of the second injection holes 820, and the first injection holes 810 and the second injection holes 820 are arranged in axial staggered manner along the fuel injector 800, the radial flange 400 includes first radial flanges 400a corresponding to the first injection holes 810 and second radial flanges 400b corresponding to the second injection holes 820. 2 2 2 .

[0077] As shown in the embodiment of the present application, the injection holes include first injection holes 810 and second injection holes 820, the first injection holes 810 and the second injection holes 820 are alternately and spacedly arranged along the circumference of the fuel injector 800, the number of the first injection holes 810 can be same or different from the number of the second injection holes 820, and the first injection holes 810 and the second injection holes 820 are arranged in axial staggered manner along the fuel injector 800, the radial flange 400 includes first radial flanges 400a corresponding to the first injection holes 810 and second radial flanges 400b corresponding to the second injection holes 820. 2 2 .​​​​

[0078] Based on the above-mentioned combustion system, the application provides an internal combustion engine comprising the combustion system as described in the above-mentioned embodiments. Since the internal combustion engine adopts the combustion system in the above-mentioned embodiments, the technical effects of the internal combustion engine refer to the above-mentioned embodiments.

[0079] As shown in the present application and claims, unless the context clearly indicates otherwise, the words "one", "an", "a", and / or "the" do not mean a single number, but also include a plurality. Generally, the terms "comprise" and "include" only indicate the inclusion of the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements. The element defined by the statement "comprise a" does not exclude the presence of another identical element in the process, method, product or device comprising the element.

[0080] In the description of the present application, unless otherwise explicitly limited, the words such as arrangement, installation, connection, etc. should be understood in a broad sense, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical solution.

[0081] It should be noted that each embodiment in the present specification is described in a progressive manner, and each embodiment focuses on the difference from other embodiments. The same and similar parts between the embodiments can be understood by mutual reference.

[0082] The principles and implementation modes of the present application are described by applying specific examples in the present text. The above description of the embodiments is only for the purpose of helping to understand the core idea of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways, and these improvements and modifications also fall within the protection scope of the claims of the present application.

Claims

1. A piston characterized by, The top of the piston (100) is provided with a combustion chamber pit (200), the circumferential wall surface of the combustion chamber pit (200) is sequentially provided with a first flow guide surface (210) and a second flow guide surface (220) from the bottom surface of the combustion chamber pit (200) to the top surface (500) of the piston (100), the first flow guide surface (210) is recessed away from the axis direction of the piston (100), the second flow guide surface (220) is recessed away from the bottom surface of the cylinder head, the first flow guide surface (210) and the second flow guide surface (220) are smoothly connected to form a first circumferential flange (300) protruding towards the nozzle direction of the fuel injector (800), a plurality of radial flanges (400) protruding towards the nozzle direction of the fuel injector (800) are arranged on the circumferential wall surface of the combustion chamber pit (200) at intervals, the radial flanges (400) are symmetrically arranged about the radial surface of the piston (100), the radial flanges (400) correspond one-to-one to the nozzles of the fuel injector (800), the lower end of the radial flange (400) extends to the bottom surface of the combustion chamber pit (200), and the upper end extends to the second flow guide surface (220), the part of the radial flange (400) located on the first circumferential flange (300) is arranged opposite to the nozzle of the fuel injector (800), the radial flange (400) includes a first flange part (410), a second flange part (420) and a third flange part (430) connected in sequence from the bottom surface of the combustion chamber pit (200) to the top surface (500) of the piston (100), the second flange part (420) is located on the surface of the first circumferential flange (300), the circumferential dimension of the second flange part (420) is greater than the circumferential dimensions of the first flange part (410) and the third flange part (430), and the second flange part (420) is arranged opposite to the nozzle of the fuel injector (800); The radial flange (400) includes a first radial flange (400a) and a second radial flange (400b), a plurality of first radial flanges (400a) and a plurality of second radial flanges (400b) are alternately and interval arranged along the circumference of the combustion chamber pit (200), the first radial flange (400a) is arranged one-to-one corresponding to the first nozzle (810) on the fuel injector (800), the second radial flange (400b) is arranged one-to-one corresponding to the second nozzle (820) on the fuel injector (800), and the ratio of the volume of the first radial flange (400a) to the volume of the second radial flange (400b) is equal to the ratio of the fuel injection amount of the first nozzle (810) to the fuel injection amount of the second nozzle (820).

2. The piston of claim 1 wherein, The surfaces of the first flange portion (410), the second flange portion (420) and the third flange portion (430) are all smooth curves, and the smooth curve radius r1 of the first flange portion (410), the smooth curve radius r2 of the second flange portion (420) and the smooth curve radius r3 of the third flange portion (430) satisfy r1 < r2 < r3.

3. The piston according to claim 2, characterized in that The surface of the first circumferential flange (300) is a smooth curve, and the smooth curve radius r4 of the first circumferential flange (300) and the smooth curve radius r2 of the second flange portion (420) satisfy r2 ≤ r4.

4. The piston of any one of claims 1-3, wherein, In the direction from the bottom surface of the combustion chamber pit (200) to the top surface (500) of the piston (100), the circumferential dimension of the first flange portion (410) gradually increases, and / or the circumferential dimension of the third flange portion (430) gradually increases.

5. The piston of any one of claims 1-3, wherein, The circumferential side wall of the combustion chamber pit (200) further comprises a third flow guide surface (230) arranged between the second flow guide surface (220) and the top surface (500) of the piston (100), and the second flow guide surface (220) and the third flow guide surface (230) are connected in a smooth transition to form a second circumferential flange (600) protruding in the direction of the bottom surface of the cylinder head or the injection hole of the fuel injector (800), the radial distance between the first circumferential flange (300), the second circumferential flange (600) and the upper edge of the circumferential wall surface of the combustion chamber pit (200) and the axis of the piston (100) increases in turn, and the third flow guide surface (230) is recessed in the direction away from the bottom surface of the cylinder head.

6. The piston of claim 5 wherein, The circumferential wall surface of the combustion chamber pit (200) further comprises a fourth flow guide surface (240), and the third flow guide surface (230) is connected to the top surface (500) of the piston (100) through the fourth flow guide surface (240), and the fourth flow guide surface (240) protrudes in the direction of the bottom surface of the cylinder head.

7. The piston of any one of claims 1-3, wherein, The bottom of the combustion chamber pit (200) is provided with a center boss (700) protruding in the direction of the bottom surface of the cylinder head, the circumferential wall surface of the combustion chamber pit (200) is arranged around the center boss (700), and the bottom of the surface of the center boss (700) is connected in a smooth transition to the first flow guide surface (210).

8. The piston of claim 7 wherein, The surface of the center boss (700) comprises a fifth flow guide surface (710), a flow guide slope surface (720) and a sixth flow guide surface (730), the fifth flow guide surface (710) is located at the top of the center boss (700), the fifth flow guide surface (710) is connected in a smooth transition to the sixth flow guide surface (730) through the flow guide slope surface (720), the sixth flow guide surface (730) is connected in a smooth transition to the first flow guide surface (210), and the diameter of the flow guide slope surface (720) gradually increases in the direction from the fifth flow guide surface (710) to the sixth flow guide surface (730).

9. A combustion system characterized by, Comprise: The piston (100) is the piston (100) according to any one of claims 1-8; A fuel injector (800) is disposed on a cylinder head of the combustion system, the fuel injector (800) is provided with a plurality of injection holes in a circumferential direction, the injection holes are provided one by one with a radial flange (400) in a combustion chamber pit (200) of the piston (100), and the injection holes are located towards the part of the radial flange (400) on the first circumferential flange (300) of the piston (100).

10. An internal combustion engine characterized by comprising: The combustion system comprises the fuel injector (800) according to claim 9.

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