Fuel injector, engine and engine combustion chamber parameter design method

Abstract

The invention belongs to the technical field of engines, and discloses a fuel injector, an engine and an engine combustion chamber parameter design method.The fuel injector is provided with a first fuel injection hole set and a second fuel injection hole set, and the first fuel injection hole set and the second fuel injection hole set are sequentially arranged in the axial direction of the fuel injector; fuel oil in the first oil injection holes still continuously flows in the extending direction of the first oil injection holes after passing through the second end, continuously flows in the extending direction of the inner wall of the combustion chamber after flowing to the inner wall of the combustion chamber and rotates in the combustion chamber, so that the fuel oil injected by the multiple first oil injection holes generates vortex in the circumferential direction of the fuel oil injector; therefore, the swirl ratio in the cylinder is increased, and a high-swirl-ratio cylinder cover is not needed; and meanwhile, the fuel oil duration can be shortened through the arrangement of the double-layer oil injection hole sets, then the combustion duration is shortened, and fuel oil injection can be more uniform.

Description

Technical Field

[0001] The invention relates to the technical field of engines, and in particular to a fuel injector, an engine and a method for designing parameters of an engine combustion chamber. Background Art

[0002] The fuel injector is used to inject fuel into the engine combustion chamber. In order to reduce the generation of soot, it is necessary to ensure that there is a certain swirl ratio in the cylinder. Figure 1-Figure 2 As shown, the injector 1000 has an inner cavity 3000 for fuel to enter and a plurality of injection holes 2000 arranged on the outer wall of the injector 1000, wherein the injection holes 2000 are connected to the inner cavity 3000 and are used to inject fuel into the combustion chamber, wherein the plurality of injection holes 2000 are radially arranged, and the fuel beams injected by the injection holes 2000 do not move along the circumferential direction of the injector 1000, and therefore will not increase the swirl ratio in the cylinder but will reduce the swirl ratio in the cylinder. At this time, in order to meet the demand for the swirl ratio in the cylinder, a cylinder head that can increase the swirl ratio needs to be provided, but this type of cylinder head has a low flow coefficient, which will result in a reduction in the amount of fresh air in the cylinder and an increase in fuel consumption. Summary of the invention

[0003] According to one aspect of the present invention, the present invention provides a fuel injector capable of increasing the swirl ratio in a cylinder while ensuring the injection amount.

[0004] To achieve the above object, the present invention adopts the following technical solutions:

[0005] A fuel injector, used for injecting fuel into a combustion chamber of a cylinder, the fuel injector having a first fuel injection hole group and a second fuel injection hole group, wherein the first fuel injection hole group and the second fuel injection hole group are sequentially arranged along the axial direction of the fuel injector;

[0006] The first fuel injection hole group comprises a plurality of first fuel injection holes arranged at intervals along the circumferential direction of the fuel injector, one end of each of the plurality of first fuel injection holes is used for fuel to enter, and the other end is communicated with the combustion chamber, and the projection of the first fuel injection holes on a plane perpendicular to the axis of the fuel injector forms an angle with the radial direction of the fuel injector;

[0007] The second fuel injection hole group includes a plurality of second fuel injection holes arranged at intervals along the circumferential direction of the fuel injector, one end of each of the second fuel injection holes is used for fuel entry, and the other end is connected to the combustion chamber, and the projection of the second fuel injection holes on a plane perpendicular to the axis of the fuel injector extends along the radial direction of the fuel injector.

[0008] As a preferred embodiment of the fuel injector, the lower end of the fuel injector extends into the combustion chamber, and the second injection hole group is located below the first injection hole group; the angle between the extension direction of the plurality of first injection holes and the axis of the fuel injector is a first injection cone angle, and the angle between the extension direction of the plurality of second injection holes and the axis of the fuel injector is a second injection cone angle, and the second injection cone angle is smaller than the first injection cone angle.

[0009] As a preferred solution of the fuel injector, the lower end of the fuel injector extends into the combustion chamber, and the second fuel injection hole group is located below the first fuel injection hole group; the apertures of the plurality of first fuel injection holes are all r1, and the apertures of the plurality of second fuel injection holes are all r2, and r1 and r2 satisfy: 0.35≤r1 2 / (r1 2 +r2 2 )≤0.45.

[0010] As a preferred solution of the fuel injector, the included angle between the projection of the first injection hole on a plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector is θ, and θ satisfies: 10°≤θ≤60°.

[0011] According to another aspect of the present invention, an engine is provided, comprising a cylinder and the above-mentioned fuel injector, wherein the cylinder comprises a cylinder body, a cylinder head connected to the cylinder body and a piston arranged in the cylinder body, the fuel injector is arranged in the cylinder head, and the inner wall of the cylinder body, the inner wall of the cylinder head and the top wall of the piston together form the combustion chamber.

[0012] As a preferred embodiment of the engine, the top wall of the piston has a first protrusion and a second protrusion, the first protrusion is arranged opposite to the first fuel injection hole group, and the fuel beam sprayed from the first fuel injection hole can be sprayed toward the first protrusion; the second protrusion is arranged opposite to the second fuel injection hole group, and the fuel beam sprayed from the second fuel injection hole can be sprayed toward the second protrusion.

[0013] As a preferred embodiment of the engine, the first protrusion is provided with a first reinforcing rib, and a plurality of the first reinforcing ribs are provided. The plurality of the first reinforcing ribs are arranged in a one-to-one correspondence with the plurality of the first fuel injection holes, and the fuel beams sprayed from the plurality of the first fuel injection holes can be ejected one-to-one to the plurality of the first reinforcing ribs; the second protrusion is provided with a second reinforcing rib, and a plurality of the second reinforcing ribs are provided. The plurality of the second reinforcing ribs are arranged in a one-to-one correspondence with the plurality of the second fuel injection holes, and the fuel beams sprayed from the plurality of the second fuel injection holes can be ejected one-to-one to the plurality of the second reinforcing ribs.

[0014] According to another aspect of the present invention, there is provided a method for designing engine combustion chamber parameters, which is implemented by the above engine;

[0015] The engine combustion chamber parameter design method comprises:

[0016] S100: Acquire the volume of the combustion chamber and the fuel injection amount of the fuel injector;

[0017] S200: determining a diameter of the first fuel injection hole and a diameter of the second fuel injection hole;

[0018] S300: determining an angle between a projection of the first fuel injection hole on a plane perpendicular to the axis of the fuel injector and a radial direction of the fuel injector, determining a shape of the piston top wall, and determining positions and lengths of the first reinforcement rib and the second reinforcement rib;

[0019] Wherein, determining the position and length of the first reinforcing rib and the second reinforcing rib comprises:

[0020] Obtain the fuel injection start time and injection duration of the engine in one cycle;

[0021] Obtaining a first landing point of the fuel beam injected by the fuel injector on the first protrusion to determine the position of the first reinforcing rib, and determining the length of the first reinforcing rib based on the injection start time and injection duration of the engine in one cycle; obtaining a second landing point of the fuel beam injected by the fuel injector on the second protrusion to determine the position of the second reinforcing rib, and determining the length of the second reinforcing rib based on the injection start time and injection duration of the engine in one cycle;

[0022] S400: Perform simulation analysis, draw a simulation curve of the change of the swirl ratio in the cylinder, and obtain the fuel consumption, smoke generation and nitrogen oxide generation;

[0023] S500: Obtaining a maximum deviation value between the simulation curve and the target curve, and determining a magnitude between the maximum deviation value and a preset deviation value;

[0024] If the maximum deviation value is less than the preset deviation value, executing step S600;

[0025] S600: determining whether the fuel consumption is within a set fuel consumption range, determining whether the smoke generation amount is within a set smoke generation range, and determining whether the nitrogen oxide generation amount is within a set nitrogen oxide range;

[0026] If the fuel consumption is within the set fuel consumption range, the smoke generation is within the set smoke generation range, and the nitrogen oxide generation is within the set nitrogen oxide range, it is determined that the design of the combustion chamber meets the requirements.

[0027] As a preferred solution of the engine combustion chamber parameter design method, obtaining the fuel injection start time and fuel injection duration of the engine in one cycle includes:

[0028] Select the running state of the engine and obtain the injection pulse width Tim and fuel injector closing delay pulse width Tim of the engine corresponding to the running state 关闭 And the fuel injector opening delay pulse width Tim 开启 ;

[0029] The injection duration of the engine in one cycle under this operating state is obtained based on the following formula, where CA1 is the size of the crankshaft angle corresponding to the injection duration:

[0030] CA1=6n(Tim+Tim 关闭 -Tim 开启 ) / 1000000, where n is the engine speed corresponding to the selected operating state;

[0031] The injection advance angle CA2 of the engine in this operating state is obtained to obtain the injection start time.

[0032] As a preferred solution of the method for designing engine combustion chamber parameters, in step S500, if the maximum deviation value is not less than the preset deviation value, then return to step S300;

[0033] In step S600, if the fuel consumption is not within the set fuel consumption range, or the smoke generation amount is not within the set smoke generation range, or the nitrogen oxide generation amount is not within the set nitrogen oxide range, then the process returns to step S200.

[0034] The beneficial effects of the present invention are:

[0035] The present invention provides a fuel injector for injecting fuel into a combustion chamber of a cylinder. The fuel injector has a first injection hole group and a second injection hole group. The first injection hole group and the second injection hole group are sequentially arranged along the axial direction of the fuel injector. The first injection hole group includes a plurality of first injection holes arranged at intervals along the circumferential direction of the fuel injector. One end of the plurality of first injection holes is used for fuel to enter, and the other end is connected to the combustion chamber. The projection of the first injection hole on a plane perpendicular to the axis of the fuel injector forms an angle with the radial direction of the fuel injector, so that the fuel in the first injection hole continues to flow in the extension direction of the first injection hole after passing through the second end, and continues to flow in the extension direction of the inner wall of the combustion chamber after flowing to the inner wall of the combustion chamber, and rotates in the combustion chamber, so that the fuel injected by the plurality of first injection holes generates vortices along the circumferential direction of the fuel injector, thereby increasing the vortex ratio in the cylinder, and no high vortex ratio cylinder head is required. The second fuel injection hole group includes a plurality of second fuel injection holes arranged at intervals along the circumferential direction of the fuel injector, one end of each of the plurality of second fuel injection holes is used for fuel to enter, and the other end is connected to the combustion chamber, and the projection of the second fuel injection holes on a plane perpendicular to the axis of the fuel injector extends along the radial direction of the fuel injector. Compared with the first fuel injection hole, the second fuel injection hole is arranged directly opposite to the center line of the fuel injector, and the resistance encountered by the fuel when flowing in the second fuel injection hole is smaller, so that the fuel can more easily enter the second fuel injection hole from the inner cavity of the fuel injector. In addition, by setting a double-layer fuel injection hole group, the fuel duration can be shortened, thereby shortening the combustion duration, and the fuel injection can be made more uniform.

[0036] The present invention also provides an engine, including the above-mentioned fuel injector, the cylinder includes a cylinder body, a cylinder head connected to the cylinder body, and a piston arranged in the cylinder body, the fuel injector is arranged in the cylinder head, the inner wall of the cylinder body, the inner wall of the cylinder head and the top wall of the piston together form a combustion chamber, in the fuel injector, the fuel in the first injection hole continues to flow in the extension direction of the first injection hole after passing through the second end, and after flowing to the inner wall of the combustion chamber, it continues to flow along the extension direction of the inner wall of the combustion chamber and rotates in the combustion chamber, so that the fuel injected by the multiple first injection holes generates vortexes along the circumferential direction of the fuel injector, thereby increasing the vortex ratio in the cylinder, and there is no need to use a high vortex ratio cylinder head. In addition, by setting a double-layer injection hole group, the fuel duration can be shortened, thereby shortening the combustion duration, and the fuel injection can be made more uniform.

[0037] The present invention also provides a method for designing parameters of an engine combustion chamber, by obtaining the volume of the combustion chamber and the injection amount of the fuel injector, determining the aperture of the first injection hole and the aperture of the second injection hole, determining the angle between the projection of the first injection hole on a plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, determining the shape of the piston top wall, and determining the position and length of the first reinforcing rib and the second reinforcing rib, then performing simulation analysis, drawing a simulation curve of the change of the swirl ratio in the cylinder, and obtaining the fuel consumption, smoke generation and nitrogen oxide generation, obtaining the maximum deviation value between the simulation curve and the target curve, and judging the size of the maximum deviation value and the preset deviation value, if the maximum deviation value is less than the preset deviation value, judging whether the fuel consumption is within the set range of fuel consumption, Determine whether the smoke generation is within the set range of smoke, and determine whether the nitrogen oxide generation is within the set range of nitrogen oxide. If the fuel consumption is within the set range, the smoke generation is within the set range of smoke, and the nitrogen oxide generation is within the set range of nitrogen oxide, then it indicates that the aperture of the first injection hole and the aperture of the second injection hole, the angle between the projection of the first injection hole on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, the shape of the piston top wall, the position and length of the first reinforcement rib and the second reinforcement rib meet the requirements of the combustion chamber for the in-cylinder swirl ratio, fuel consumption, smoke generation and nitrogen oxide generation. It can be determined that the design of the combustion chamber meets the requirements, and the design of the combustion chamber is completed through simulation analysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is the first structural schematic diagram of the fuel injector in the prior art;

[0039] Figure 2 It is a second structural schematic diagram of a fuel injector in the prior art;

[0040] Figure 3 is a first structural schematic diagram of a fuel injector in an embodiment of the present invention;

[0041] Figure 4 is a second structural schematic diagram of a fuel injector in an embodiment of the present invention;

[0042] Figure 5 is a third structural schematic diagram of a fuel injector in an embodiment of the present invention;

[0043] Figure 6 is a fourth structural schematic diagram of a fuel injector in an embodiment of the present invention;

[0044] Figure 7 is a partial structural schematic diagram of a fuel injector in an embodiment of the present invention;

[0045] Figure 8 is a structural schematic diagram of a second fuel injection hole group of another fuel injector in an embodiment of the present invention;

[0046] Fig. 9 1 is a schematic diagram of the overall effect of a first fuel injection hole group and a second fuel injection hole group of another fuel injector in an embodiment of the present invention;

[0047] Fig.10 is a first structural schematic diagram of a piston in an embodiment of the present invention;

[0048] Fig.11 is a second structural schematic diagram of the piston in an embodiment of the present invention;

[0049] Fig.12 is a schematic structural diagram of a piston top wall in an embodiment of the present invention;

[0050] Fig.13 is a flow chart of a method for designing engine combustion chamber parameters in an embodiment of the present invention;

[0051] Fig.14 Schematic diagram of a target curve in an embodiment of the present invention.

[0052] In the figure:

[0053] 1000, fuel injector; 2000, fuel injection hole; 3000, inner cavity;

[0054] 100. Combustion chamber;

[0055] 200, piston; 201, first protrusion; 202, second protrusion; 203, first reinforcing rib; 204, second reinforcing rib;

[0056] 211, connecting section; 212, first extension section; 213, second extension section; 214, third extension section; 215, fourth extension section; 216, fifth extension section; 217, plane extension section;

[0057] 1. The first fuel injection hole group; 11. The first fuel injection hole;

[0058] 2. The second fuel injection hole group; 21. The second fuel injection hole;

[0059] 3. Inner cavity. DETAILED DESCRIPTION

[0060] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0061] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0062] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0063] In the description of this embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operate in a specific direction, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0064] Embodiment 1

[0065] The fuel injector is used to inject fuel into the combustion chamber of the engine. In order to reduce the generation of soot, it is necessary to ensure that there is a certain swirl ratio in the cylinder. The existing injector has an inner cavity for fuel to enter and a plurality of injection holes arranged on the outer wall of the injector. The injection holes are connected to the inner cavity and are used to inject fuel into the combustion chamber. Among them, the multiple injection holes are arranged radially, and the fuel beams injected by the injection holes will not move along the circumferential direction of the injector. Therefore, not only will the swirl ratio in the cylinder not be increased, but it will be reduced. At this time, in order to meet the demand for the swirl ratio in the cylinder, it is necessary to set a cylinder head that can increase the swirl ratio. However, the flow coefficient of this type of cylinder head is low, which will lead to a decrease in the amount of fresh air in the cylinder and increase the fuel consumption rate.

[0066] Reference Figure 3-Figure 7The fuel injector is used to inject fuel into the combustion chamber 100 of the cylinder. The fuel injector has a first injection hole group 1 and a second injection hole group 2. The first injection hole group 1 and the second injection hole group 2 are arranged in sequence along the axial direction of the fuel injector. The first injection hole group 1 includes a plurality of first injection holes 11 arranged at intervals along the circumferential direction of the fuel injector. One end of the plurality of first injection holes 11 is used for fuel to enter, and the other end is connected to the combustion chamber 100. The projection of the first injection hole 11 on a plane perpendicular to the axis of the fuel injector forms an angle with the radial direction of the fuel injector, so that the fuel in the first injection hole 11 continues to flow in the extension direction of the first injection hole 11 after passing through the second end, and continues to flow in the extension direction of the inner wall of the combustion chamber 100 after flowing to the inner wall of the combustion chamber 100, and rotates in the combustion chamber 100, so that the fuel injected by the plurality of first injection holes 11 generates vortexes along the circumferential direction of the fuel injector, thereby increasing the vortex ratio in the cylinder, and there is no need to use a high vortex ratio cylinder head. In this embodiment, the number of the first fuel injection holes 11 in the first fuel injection hole group 1 can be 8, 10, 12, 14 or 16, and can also be set to other numbers according to actual needs. The second fuel injection hole group 2 includes a plurality of second fuel injection holes 21 arranged at intervals along the circumferential direction of the fuel injector, one end of each of the plurality of second fuel injection holes 21 is used for fuel to enter, and the other end is connected to the combustion chamber 100, and the projection of the second fuel injection holes 21 on a plane perpendicular to the axis of the fuel injector extends along the radial direction of the fuel injector. Compared with the first fuel injection hole 11, since the second fuel injection hole 21 is arranged directly opposite to the center line of the fuel injector, the resistance encountered by the fuel when flowing in the second fuel injection hole 21 is smaller, so the fuel is more likely to enter the second fuel injection hole 21 from the inner cavity of the fuel injector. In this embodiment, the number of the second fuel injection holes 21 in the second fuel injection hole group 2 can be 8, 10, 12, 14 or 16, and can also be set to other numbers according to actual needs. In addition, by providing a double-layer fuel injection hole group, the fuel duration can be shortened, thereby shortening the combustion duration, and the fuel injection can be made more uniform.

[0067] Optionally, the fuel injector further has an inner cavity 3, the inner cavity 3 is used for fuel to enter, and the plurality of first injection holes 11 and the plurality of second injection holes 21 are all connected to the inner cavity 3 and are used for the fuel in the inner cavity 3 to enter so as to complete the injection of the fuel.

[0068] Continue to refer to Figure 3-Figure 7The lower end of the fuel injector extends into the combustion chamber 100, and the multiple first injection holes 11 and the multiple second injection holes 21 all spray fuel downward along the axis of the fuel injector. Specifically, the second injection hole group 2 is located below the first injection hole group 1; the angle between the extension direction of the multiple first injection holes 11 and the axis of the fuel injector is the first injection cone angle α1, and the angle between the extension direction of the multiple second injection holes 21 and the axis of the fuel injector is the second injection cone angle α2, and the second injection cone angle α2 is smaller than the first injection cone angle α1, so that the fuel sprayed from the two injection hole groups can be dispersed as much as possible. In this embodiment, the difference between the first spray cone angle α1 and the second spray cone angle α2 is between 4° and 10°, wherein the first spray cone angle α1 is between 146° and 154°, and specifically can be 146°, 147°, 148°, 149°, 150°, 151°, 152°, 153° or 154°; the second spray cone angle α2 is between 142° and 156°, and specifically can be 142°, 143°, 144°, 145° or 146°.

[0069] Continue to refer to Figure 3-Figure 7 , the lower end of the fuel injector extends into the combustion chamber 100, and the second injection hole group 2 is located below the first injection hole group 1; the apertures of the plurality of first injection holes 11 are all r1, and the apertures of the plurality of second injection holes 21 are all r2, and r1 and r2 satisfy: 0.35≤r1 2 / (r1 2 +r2 2 )≤0.45, so that the amount of fuel injected by the multiple first injection holes 11 accounts for 0.35-0.45 of the total amount of fuel injected by the fuel injector. Since the fuel injected by the multiple first injection holes 11 will generate vortices along the circumferential direction of the fuel injector, while the fuel injected by the multiple second injection holes 21 will not generate vortices along the circumferential direction of the fuel injector, the vortex intensity formed by the fuel injection can be adjusted by adjusting the ratio of the amount of fuel injected by the multiple first injection holes 11 to the total amount of fuel injected by the fuel injector. Among them, the ratio of the amount of fuel injected by the multiple first injection holes 11 to the total amount of fuel injected by the fuel injector can be 0.35, 0.36, 0.37, 0.38, 0.39, 0.40, 0.41, 0.42, 0.43, 0.44 or 0.45.

[0070] Optionally, a plurality of first fuel injection hole groups 1 are provided; and / or a plurality of second fuel injection hole groups 2 are provided, so that the vortex intensity formed by the fuel injection can be further adjusted according to the number of the first fuel injection hole groups 1 and the second fuel injection hole groups 2.

[0071] Continue to refer to Figure 3-Figure 7, the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector is θ, and θ satisfies: 10°≤θ≤60°. Optionally, when the engine model is an EGR engine model, the cylinder swirl ratio requirement is high, and the value of θ should be large. At this time, the value of θ is 30° to 60°, and can be specifically 30°, 31°, 32°, 33°, 34°, 35°, 36°, 37°, 38°, 39°, 40°, 41°, 42°, 43°, 44°, 45°, 46°, 47°, 48°, 49°, 50°, 51°, 52°, 53°, 54°, 55°, 56°, 57°, 58°, 59° or 60°. When the engine model is an SCR model, the cylinder swirl ratio requirement is lower and the value of θ should be smaller. At this time, the value of θ is 10°~30°, and can be specifically 10°, 11°, 12°, 13°, 14°, 15°, 16°, 17°, 18°, 19°, 20°, 21°, 22°, 23°, 24°, 25°, 26°, 27°, 28°, 29° or 30°.

[0072] As an alternative, the projection of the second fuel injection hole 21 on a plane perpendicular to the axis of the fuel injector also forms an angle with the radial direction of the fuel injector. Figure 8 The schematic diagram of the structure of the second injection hole group 2 in this scheme is shown. Fig. 9 The schematic diagram of the overall effect of the first fuel injection hole group 1 and the second fuel injection hole group 2 in this solution is shown. Figure 8-Figure 9 With such arrangement, the fuel injected from the plurality of second injection holes 21 generates vortex along the circumferential direction of the fuel injector, which cooperates with the fuel injected from the first injection hole 11 to further increase the vortex ratio in the cylinder.

[0073] Embodiment 2

[0074] This embodiment provides an engine, referring to Figure 3-Figure 7 ,as well as Figure 10-12 The engine includes the fuel injector in the above-mentioned embodiment 1, the cylinder includes a cylinder body, a cylinder head connected to the cylinder body, and a piston 200 arranged in the cylinder body, the fuel injector is arranged in the cylinder head, and the inner wall of the cylinder body, the inner wall of the cylinder head and the top wall of the piston 200 together form a combustion chamber 100. In the fuel injector, the fuel in the first injection hole 11 continues to flow in the extension direction of the first injection hole 11 after passing through the second end, and continues to flow along the extension direction of the inner wall of the combustion chamber 100 after flowing to the inner wall of the combustion chamber 100, and rotates in the combustion chamber 100, so that the fuel injected by the multiple first injection holes 11 generates vortexes along the circumferential direction of the fuel injector, thereby increasing the vortex ratio in the cylinder, and there is no need to use a high vortex ratio cylinder head. In addition, by setting a double-layer injection hole group, the fuel duration can be shortened, thereby shortening the combustion duration, and the fuel injection can be made more uniform.

[0075] Continue to refer to Figure 3-Figure 7 ,as well as Figure 10-12 The top wall of the piston 200 has a first protrusion 201 and a second protrusion 202. The first protrusion 201 is arranged opposite to the first injection hole group 1, and the fuel beam injected by the first injection hole 11 can be injected toward the first protrusion 201, thereby being split through the first protrusion 201, so that a part of the fuel beam moves toward the periphery of the piston 200, and the other part moves toward the center of the piston 200; the second protrusion 202 is arranged opposite to the second injection hole group 2, and the fuel beam injected by the second injection hole 21 can be injected toward the second protrusion 202, thereby being split through the second protrusion 202, so that a part of the fuel beam moves toward the periphery of the piston 200, and the other part moves toward the center of the piston 200.

[0076] Continue to refer to Figure 3-Figure 7 ,as well as Figure 10-12 The first protrusion 201 is provided with a first reinforcing rib 203, and a plurality of first reinforcing ribs 203 are provided. The plurality of first reinforcing ribs 203 are arranged in a one-to-one correspondence with the plurality of first fuel injection holes 11, and the fuel beams sprayed from the plurality of first fuel injection holes 11 can be ejected to the plurality of first reinforcing ribs 203 in a one-to-one correspondence, so that the fuel can be diverted and diffused along the width direction of the first reinforcing rib 203 through the first reinforcing rib 203, and then the fuel is further diverted along the radial direction of the piston 200 when flowing through the first protrusion 201, so as to increase the diversion effect of the fuel. The second protrusion 202 is provided with a second reinforcing rib 204, and a plurality of second reinforcing ribs 204 are provided. The plurality of second reinforcing ribs 204 are arranged in a one-to-one correspondence with the plurality of second fuel injection holes 21, and the fuel beams sprayed from the plurality of second fuel injection holes 21 can be ejected one-to-one to the plurality of second reinforcing ribs 204, so that the fuel can be diverted and diffused along the width direction of the second reinforcing rib 204 through the second reinforcing rib 204, and then the fuel is further diverted along the radial direction of the piston 200 when flowing through the second protrusion 202, so as to increase the diversion effect of the fuel.

[0077] Embodiment 3

[0078] This embodiment provides a method for designing engine combustion chamber parameters, and the method for designing engine combustion chamber parameters is implemented by the engine in the above-mentioned embodiment 2.

[0079] Reference Fig.13 ,The engine combustion chamber parameter design method includes the following steps.

[0080] S100: Acquire the volume of the combustion chamber 100 and the fuel injection amount of the fuel injector.

[0081] The volume of the combustion chamber 100 is the volume of the cavity between the inner wall of the cylinder body, the inner wall of the cylinder head and the top wall of the piston 200 when the piston 200 moves to the top dead center, and its value is related to the specific model of the engine. The injection amount of the fuel injector can be obtained according to the model of the fuel injector used.

[0082] S200 : Determine the hole diameter of the first fuel injection hole 11 and the hole diameter of the second fuel injection hole 21 .

[0083] The apertures of the first fuel injection holes 11 are all r1, and the apertures of the second fuel injection holes 21 are all r2, and r1 and r2 satisfy: 0.35≤r1 2 / (r1 2 +r2 2 )≤0.45. The initial values ​​of the aperture r1 of the first fuel injection hole 11 and the aperture r2 of the second fuel injection hole 21 can be set based on experience. Since the fuel injected by the multiple first fuel injection holes 11 will generate vortices along the circumferential direction of the fuel injector, while the fuel injected by the multiple second fuel injection holes 21 will not generate vortices along the circumferential direction of the fuel injector, the vortex intensity formed by the fuel injection can be adjusted by adjusting the proportion of the amount of fuel injected by the multiple first fuel injection holes 11 to the total amount of fuel injected by the fuel injector.

[0084] S300: Determine the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, determine the shape of the top wall of the piston 200, and determine the position and length of the first reinforcement rib 203 and the second reinforcement rib 204.

[0085] The angle θ between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector satisfies: 10°≤θ≤60°. Optionally, the size of θ should be determined according to the actual engine model. When the engine model is an EGR engine model, the cylinder swirl ratio requirement is high, and the value of θ should be large. At this time, the value of θ is 30° to 60°. When the engine model is an SCR engine model, the cylinder swirl ratio requirement is low, and the value of θ should be small. At this time, the value of θ is 10° to 30°.

[0086] In this embodiment, the shape of the top wall of the piston 200 is as follows:

[0087] The top wall of the piston 200 has a first protrusion 201 and a second protrusion 202, both of which are arc-shaped, and the radius of the first protrusion 201 is between 1 and 1.5 mm, specifically 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm or 1.5 mm, and the radius of the second protrusion 202 is between 3 and 3.5 mm, specifically 3 mm, 3.1 mm, 3.2 mm, 3.3 mm, 3.4 mm or 3.5 mm. Optionally, the distance between the center of the second protrusion 202 and the axis of the piston 200 is D1, and the ratio between D1 and the radius of the piston 200 is between 0.48 and 0.52, specifically 0.48, 0.49, 0.50, 0.51 or 0.52.

[0088] The top wall of the piston 200 also has a connecting section 211 located between the first protrusion 201 and the second protrusion 202. The connecting section 211 is arc-shaped, and the ratio between the radius of the connecting section 211 and the radius of the piston 200 is between 0.14 and 0.18, and can specifically be 0.14, 0.15, 0.16, 0.17 or 0.18.

[0089] The top wall of the piston 200 also has a first extension section 212 connected to the first protrusion 201 and extending toward the outer periphery of the piston 200. The first extension section 212 is arc-shaped, and the ratio between the radius of the first extension section 212 and the radius of the piston 200 is between 0.17 and 0.25, and specifically can be 0.17, 0.18, 0.19, 0.20, 0.21, 0.22, 0.23, 0.24 or 0.25.

[0090] The top wall of the piston 200 also has a second extension section 213 connected to the first extension section 212 and extending toward the outer periphery of the piston 200. The second extension section 213 is arc-shaped, and the ratio between the radius of the second extension section 213 and the radius of the piston 200 is between 0.24 and 0.3, and specifically can be 0.24, 0.25, 0.26, 0.27, 0.28, 0.29 or 0.3.

[0091] In the second extension section 213, one end close to the outer periphery of the piston 200 is connected with a plane extension section 217, the plane extension section 217 is connected to the outer peripheral wall of the piston 200, the plane extension section 217 is a plane, and is parallel to the surface of the cylinder head. In other words, the top wall of the piston 200 begins to form a groove at the connection between the second extension section 213 and the plane extension section 217, and the ratio between the distance from the connection between the second extension section 213 and the plane extension section 217 to the axis of the piston 200 and the radius of the piston 200 is between 0.88 and 0.92, and can be specifically 0.88, 0.89, 0.9, 0.91 or 0.92.

[0092] The top wall of the piston 200 also has a third extension section 214 connected to the second protrusion 202 and extending toward the center of the piston 200. The third extension section 214 extends in a direction away from the cylinder head so that a pit is formed at the position where the third extension section 214 is located. The third extension section 214 is arc-shaped so that the ratio between the depth of the pit and the radius of the piston 200 is between 0.24 and 0.27, specifically 0.24, 0.25, 0.26 or 0.27.

[0093] The top wall of the piston 200 also has a fourth extension section 215 connected to the third extension section 214 and extending toward the center of the piston 200. The fourth extension section 215 is arc-shaped, and the ratio between the radius of the fourth extension section 215 and the radius of the piston 200 is between 0.11 and 0.14, and specifically can be 0.11, 0.12, 0.13 or 0.14.

[0094] The top wall of the piston 200 also has a fifth extension section 216 connected to the fourth extension section 215 and extending toward the center of the piston 200. The fifth extension section 216 is arc-shaped, and the ratio between the radius of the fifth extension section 216 and the radius of the piston 200 is between 0.24 and 0.27, and can specifically be 0.24, 0.25, 0.26 or 0.27.

[0095] Determining the shape of the top wall of the piston 200 means determining the size parameters of each structure of the top wall of the piston 200 under the premise of meeting the above-mentioned size requirements. The initial values ​​of the size parameters of each structure of the top wall of the piston 200 can be set by the designer based on experience or with reference to existing engine models. In other embodiments, the top wall of the piston 200 can also be designed into other shapes according to actual needs, and the size parameters of each structure can be determined by referring to the above method.

[0096] Determining the position and length of the first reinforcing rib 203 and the second reinforcing rib 204 includes the following steps.

[0097] Get the injection start time and injection duration of the engine in one cycle.

[0098] The first landing point of the fuel beam injected by the fuel injector on the first protrusion 201 is obtained to determine the position of the first reinforcing rib 203, and the length of the first reinforcing rib 203 is determined based on the injection start time and injection duration of the engine in one cycle; the second landing point of the fuel beam injected by the fuel injector on the second protrusion 202 is obtained to determine the position of the second reinforcing rib 204, and the length of the second reinforcing rib 204 is determined based on the injection start time and injection duration of the engine in one cycle.

[0099] The position of the fuel beam injected onto the top wall of the piston 200 can be obtained by calculation or simulation analysis based on the injection start time and injection duration of the engine within one cycle, and the first reinforcing rib 203 or the second reinforcing rib 204 can be set at the corresponding position so that the fuel beam is directly injected onto the first reinforcing rib 203 or the second reinforcing rib 204.

[0100] Wherein, obtaining the fuel injection start time and the fuel injection duration of the engine in one cycle includes the following steps.

[0101] Select the running state of the engine and obtain the injection pulse width Tim and fuel injector closing delay pulse width Tim of the engine corresponding to the running state 关闭 And the fuel injector opening delay pulse width Tim 开启 .

[0102] The running state of the engine can be obtained from the universal characteristic diagram of the engine, specifically by selecting a common operating point on the universal characteristic diagram, such as the minimum fuel consumption point. The engine speed and torque corresponding to the operating point are the engine parameter values ​​required in the subsequent process.

[0103] The engine injection pulse width Tim can be obtained through the first correspondence between the engine speed, the injection amount and the engine injection pulse width Tim. The first correspondence can be obtained through a large number of previous tests and stored in the controller. 关闭 The pulse width Tim can be delayed according to engine speed, torque and fuel injector closing 关闭 The second corresponding relationship between the two can be obtained through a large number of previous experiments and stored in the controller. Fuel injector opening delay pulse width Tim 开启 The pulse width Tim can be delayed according to the engine speed, torque and fuel injector closing delay 开启 The third corresponding relationship between them can be obtained through a large number of experiments in the early stage and stored in the controller.

[0104] The injection duration of the engine in one cycle is obtained based on the following formula, where CA1 is the crankshaft angle corresponding to the injection duration:

[0105] CA1=6n(Tim+Tim 关闭 -Tim 开启 ) / 1000000.

[0106] The size of CA1 is the size of the injection duration of the engine in one cycle under the operating state, and n is the engine speed corresponding to the selected operating state.

[0107] The injection advance angle CA2 of the engine in this operating state is obtained, and then the crankshaft angle corresponding to the start time of the engine injection can be obtained, and the range of the crankshaft angle corresponding to the injection duration is obtained through the above CA1, thereby obtaining the range of the crankshaft angle of the engine in the entire injection cycle. In addition, the position of the piston 200 under the above crankshaft angle range can be used to obtain the landing point and range of the fuel beam on the top wall of the piston 200, and then the position and length of the corresponding reinforcement rib can be obtained.

[0108] After completing step S300 , step S400 is executed.

[0109] S400: Perform simulation analysis, draw a simulation curve of the change of the swirl ratio in the cylinder, and obtain the fuel consumption, smoke generation and nitrogen oxide generation.

[0110] The simulation curve is specifically a simulation curve of the change of the swirl ratio in the cylinder with the crankshaft angle.

[0111] Among them, the methods for obtaining the in-cylinder swirl ratio, fuel consumption, smoke generation and nitrogen oxide generation are all relatively common technologies in simulation analysis, which will not be elaborated here.

[0112] S500: Obtaining a maximum deviation value between the simulation curve and the target curve, and determining a magnitude between the maximum deviation value and a preset deviation value.

[0113] The target curve is a curve showing the variation of the in-cylinder swirl ratio with the crankshaft angle under ideal conditions, and the maximum deviation between the simulation curve and the target curve represents the difference between the swirl ratio obtained during the actual simulation and the swirl ratio under ideal conditions.

[0114] In this embodiment, the target curve is as follows: Fig.14 As shown, the horizontal axis is the crankshaft angle, the vertical axis is the cylinder swirl ratio, the solid line is the curve of the cylinder swirl ratio changing with the crankshaft angle when a low swirl ratio cylinder head is used, the dotted line is the curve of the cylinder swirl ratio changing with the crankshaft angle when a high swirl ratio cylinder head is used, and the dotted line is the target curve in this embodiment. Since a high swirl ratio cylinder head is not required in this solution, before the start of fuel injection, the difference between the cylinder swirl ratio and the cylinder swirl ratio when a low swirl ratio cylinder head is used is small, and after the start of fuel injection, the cylinder swirl ratio rises, and the cylinder swirl ratio can reach the level when a high swirl ratio cylinder head is used. Among them, the target curve is obtained through a large number of simulations or experiments in the early stage.

[0115] Specifically, several points can be selected from the simulation curve and compared with the corresponding points on the target curve, and the point with the largest difference is taken as the maximum deviation value Δ max .

[0116] If the maximum deviation value is smaller than the preset deviation value, step S600 is executed.

[0117] Maximum deviation Δ max The eddy current ratio on the corresponding simulation curve is Swril 优化 , the target swirl ratio on the corresponding target curve is Swril 目标 , that is, Δ max = |Swril 优化 -Swril 目标 |. Optionally, in this embodiment, the preset deviation value is Swril 目标 That is, if |Swril 优化 -Swril 目标 | / Swril 目标 <5%, it is considered to meet the design requirements.

[0118] Optionally, in step S500, if the maximum deviation value is not less than the preset deviation value, it indicates that the deviation between the swirl ratio obtained by simulation and the target swirl ratio is large, indicating that under the condition of the current aperture, the in-cylinder swirl ratio cannot meet the demand, and then return to step S300, re-determine the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, determine the shape of the top wall of the piston 200, and determine the position and length of the first reinforcing rib 203 and the second reinforcing rib 204, and perform subsequent steps. Further optionally, since the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector directly affects the swirl intensity in the cylinder, therefore, after returning to step S300, the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector can be preferentially adjusted, and the position and length of the first reinforcing rib 203 and the second reinforcing rib 204 are correspondingly adjusted, and subsequent steps are performed. If the maximum deviation value is still not less than the preset deviation value at this time, return to step S300 again. At this time, in addition to continuing to change the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, the dimensional parameters of each structure of the top wall of the piston 200 can also be adjusted, and the simulation analysis is performed again until the maximum deviation value is less than the preset deviation value, that is, the swirl ratio in the cylinder can meet the requirements, and then execute step S600.

[0119] S600: Determine whether the fuel consumption is within a set fuel consumption range, determine whether the smoke generation is within a set smoke generation range, and determine whether the nitrogen oxide generation is within a set nitrogen oxide generation range.

[0120] If the fuel consumption is within the set fuel consumption range, the smoke generation is within the set smoke generation range, and the nitrogen oxide generation is within the set nitrogen oxide range, it is determined that the design of the combustion chamber 100 meets the requirements.

[0121] Specifically, the simulated fuel consumption is ISFC 优化, the target fuel consumption is ISFC 目标 , if both satisfy (ISFC 优化 -ISFC 目标 ) / ISFC 目标 <10%, the fuel consumption can be considered to be within the set fuel consumption range.

[0122] Specifically, the simulated smoke generation amount is SOOT 优化 , the target smoke generation is SOOT 目标 , if both satisfy |(SOOT 优化 -SOOT 目标 ) / SOOT 目标 |<20%, the smoke generation can be considered to be within the set smoke range.

[0123] Specifically, the simulated nitrogen oxide generation is NOx 优化 , the target nitrogen oxide generation is NOx 目标 , if both satisfy |(NOx 优化 -NOx 目标 ) / NOx 目标 |<10%, the nitrogen oxide generation can be considered to be within the nitrogen oxide setting range.

[0124] Optionally, in step S600, if the fuel consumption is not within the set range of fuel consumption, or the smoke generation is not within the set range of smoke, or the nitrogen oxide generation is not within the set range of nitrogen oxide, it indicates that at least one of the fuel consumption, smoke generation and nitrogen oxide generation does not meet the requirements. At this time, return to step S200 to fine-tune the values ​​of the aperture r1 of the first fuel injection hole 11 and the aperture r2 of the second fuel injection hole 21. When returning to step S200 for the first time, only the aperture r1 of the first fuel injection hole 11 and the aperture r2 of the second fuel injection hole 21 can be adjusted. Step S300 corresponds to The parameters remain unchanged, and the simulation analysis is performed again. If at least one of the fuel consumption, smoke generation and nitrogen oxide generation still does not meet the requirements, when returning to step S200 again, the aperture r1 of the first injection hole 11 and the aperture r2 of the second injection hole 21 can be adjusted, and the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector can be changed, or the size parameters of each structure of the top wall of the piston 200 can be adjusted, and the position and length of the first reinforcement rib 203 and the second reinforcement rib 204 can be adjusted accordingly, and the subsequent steps can be executed.

[0125] The engine combustion chamber parameter design method provided in this embodiment obtains the volume of the combustion chamber 100 and the injection amount of the fuel injector, determines the aperture of the first injection hole 11 and the aperture of the second injection hole 21, determines the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, determines the shape of the top wall of the piston 200, and determines the position and length of the first reinforcing rib 203 and the second reinforcing rib 204, then performs simulation analysis, draws a simulation curve of the change of the swirl ratio in the cylinder, and obtains the fuel consumption, smoke generation and nitrogen oxide generation, obtains the maximum deviation value between the simulation curve and the target curve, and judges the size of the maximum deviation value and the preset deviation value. If the maximum deviation value is less than the preset deviation value, it is judged whether the fuel consumption is within the set range of fuel consumption, and whether the smoke generation is Whether it is within the set range of smoke density, and whether the amount of nitrogen oxides generated is within the set range of nitrogen oxides, if the fuel consumption is within the set range of fuel consumption, the amount of smoke generated is within the set range of smoke density, and the amount of nitrogen oxides generated is within the set range of nitrogen oxides, it indicates that at this time, the engine is in the selected operating state, the aperture of the first injection hole 11 and the aperture of the second injection hole 21, the angle between the projection of the first injection hole 11 on the plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, the shape of the top wall of the piston 200, the position and length of the first reinforcement rib 203 and the second reinforcement rib 204 meet the requirements of the combustion chamber for the cylinder swirl ratio, fuel consumption, smoke generation and nitrogen oxide generation, and it can be determined that the design of the combustion chamber 100 meets the requirements, so as to complete the design of the combustion chamber 100 through the simulation analysis method. Since the selected operating state corresponds to the common operating point of the engine, the combustion chamber 100 obtained by this design method can meet the use requirements of the engine under the common operating point.

[0126] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. For those skilled in the art, various obvious changes, readjustments and substitutions can be made without departing from the protection scope of the present invention. It is not necessary and impossible to list all the embodiments here. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. A fuel injector for injecting fuel into a combustion chamber (100) of a cylinder, characterized in that: The fuel injector comprises a first fuel injection hole group (1) and a second fuel injection hole group (2), wherein the first fuel injection hole group (1) and the second fuel injection hole group (2) are arranged in sequence along the axial direction of the fuel injector; The first fuel injection hole group (1) comprises a plurality of first fuel injection holes (11) arranged at intervals along the circumferential direction of the fuel injector, one end of each of the plurality of first fuel injection holes (11) is used for fuel to enter, and the other end is connected to the combustion chamber (100), and the projection of the first fuel injection holes (11) on a plane perpendicular to the axis of the fuel injector forms an angle with the radial direction of the fuel injector; The second fuel injection hole group (2) comprises a plurality of second fuel injection holes (21) arranged at intervals along the circumferential direction of the fuel injector, one end of each of the plurality of second fuel injection holes (21) is used for fuel entry, and the other end is connected to the combustion chamber (100), and the projection of the second fuel injection holes (21) on a plane perpendicular to the axis of the fuel injector extends along the radial direction of the fuel injector.

2. The fuel injector according to claim 1, characterized in that The lower end of the fuel injector extends into the combustion chamber (100), and the second fuel injection hole group (2) is located below the first fuel injection hole group (1); the angle between the extension direction of the plurality of first fuel injection holes (11) and the axis of the fuel injector is a first injection cone angle, and the angle between the extension direction of the plurality of second fuel injection holes (21) and the axis of the fuel injector is a second injection cone angle, and the second injection cone angle is smaller than the first injection cone angle.

3. The fuel injector according to claim 1, characterized in that The lower end of the fuel injector extends into the combustion chamber (100), and the second fuel injection hole group (2) is located below the first fuel injection hole group (1); the apertures of the plurality of first fuel injection holes (11) are all r1, and the apertures of the plurality of second fuel injection holes (21) are all r2, and r1 and r2 satisfy: 0.35≤r1 2 / (r1 2 +r2 2 )≤0.

45.

4. The fuel injector according to claim 1, characterized in that The included angle between the projection of the first fuel injection hole (11) on a plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector is θ, and θ satisfies: 10°≤θ≤60°.

5. An engine, characterized in that It comprises a cylinder and a fuel injector as claimed in any one of claims 1 to 4, wherein the cylinder comprises a cylinder body, a cylinder head connected to the cylinder body and a piston (200) arranged in the cylinder body, the fuel injector is arranged in the cylinder head, and the inner wall of the cylinder body, the inner wall of the cylinder head and the top wall of the piston (200) together form the combustion chamber (100).

6. The engine according to claim 5, characterized in that The top wall of the piston (200) has a first protrusion (201) and a second protrusion (202); the first protrusion (201) is arranged opposite to the first fuel injection hole group (1), and the fuel beam sprayed by the first fuel injection hole (11) can be sprayed toward the first protrusion (201); the second protrusion (202) is arranged opposite to the second fuel injection hole group (2), and the fuel beam sprayed by the second fuel injection hole (21) can be sprayed toward the second protrusion (202).

7. The engine according to claim 6, characterized in that The first protrusion (201) is provided with a first reinforcing rib (203), and a plurality of the first reinforcing ribs (203) are provided. The plurality of the first reinforcing ribs (203) are provided in a one-to-one correspondence with the plurality of the first fuel injection holes (11), and the fuel beams sprayed by the plurality of the first fuel injection holes (11) can be sprayed toward the plurality of the first reinforcing ribs (203) in a one-to-one correspondence; the second protrusion (202) is provided with a second reinforcing rib (204), and a plurality of the second reinforcing ribs (204) are provided. The plurality of the second reinforcing ribs (204) are provided in a one-to-one correspondence with the plurality of the second fuel injection holes (21), and the fuel beams sprayed by the plurality of the second fuel injection holes (21) can be sprayed toward the plurality of the second reinforcing ribs (204) in a one-to-one correspondence.

8. The method for designing engine combustion chamber parameters is characterized in that: By the engine as claimed in claim 7; The engine combustion chamber parameter design method comprises: S100: obtaining the volume of the combustion chamber (100) and the fuel injection amount of the fuel injector; S200: determining the aperture of the first fuel injection hole (11) and the aperture of the second fuel injection hole (21); S300: determining the angle between the projection of the first fuel injection hole (11) on a plane perpendicular to the axis of the fuel injector and the radial direction of the fuel injector, determining the shape of the top wall of the piston (200), and determining the position and length of the first reinforcing rib (203) and the second reinforcing rib (204); Wherein, determining the position and length of the first reinforcing rib (203) and the second reinforcing rib (204) includes: Obtain the fuel injection start time and injection duration of the engine in one cycle; Obtaining a first landing point of the fuel beam injected by the fuel injector on the first protrusion (201) to determine the position of the first reinforcing rib (203), and determining the length of the first reinforcing rib (203) based on the injection start time and injection duration of the engine in one cycle; obtaining a second landing point of the fuel beam injected by the fuel injector on the second protrusion (202) to determine the position of the second reinforcing rib (204), and determining the length of the second reinforcing rib (204) based on the injection start time and injection duration of the engine in one cycle; S400: Perform simulation analysis, draw a simulation curve of the change of the swirl ratio in the cylinder, and obtain the fuel consumption, smoke generation and nitrogen oxide generation; S500: Obtaining a maximum deviation value between the simulation curve and the target curve, and determining a magnitude between the maximum deviation value and a preset deviation value; If the maximum deviation value is less than the preset deviation value, executing step S600; S600: determining whether the fuel consumption is within a set fuel consumption range, determining whether the smoke generation amount is within a set smoke generation range, and determining whether the nitrogen oxide generation amount is within a set nitrogen oxide range; If the fuel consumption is within the set fuel consumption range, the smoke generation is within the set smoke generation range, and the nitrogen oxide generation is within the set nitrogen oxide range, it is determined that the design of the combustion chamber (100) meets the requirements.

9. The method for designing engine combustion chamber parameters according to claim 8, characterized in that: Obtaining the injection start time and injection duration of the engine in a cycle includes: Select the running state of the engine and obtain the injection pulse width Tim and fuel injector closing delay pulse width Tim of the engine corresponding to the running state 关闭 And the fuel injector opening delay pulse width Tim 开启 ; The injection duration of the engine in one cycle under this operating state is obtained based on the following formula, where CA1 is the crankshaft angle corresponding to the injection duration: CA1=6n(Tim+Tim 关闭 -Tim 开启 ) / 1000000, where n is the engine speed corresponding to the selected operating state; The injection advance angle CA2 of the engine in this operating state is obtained to obtain the injection start time.

10. The method for designing engine combustion chamber parameters according to claim 8, characterized in that: In step S500, if the maximum deviation value is not less than the preset deviation value, return to step S300; In step S600, if the fuel consumption is not within the set fuel consumption range, or the smoke generation amount is not within the set smoke generation range, or the nitrogen oxide generation amount is not within the set nitrogen oxide range, then the process returns to step S200.

Images