Engine

Abstract

The utility model belongs to the technical field of engines, and discloses a piston and an engine, the top wall of the piston can enclose a combustion chamber with the inner wall of a cylinder cover and the inner wall of a cylinder body, the cylinder cover is connected with a fuel injector, and the fuel injector is used for injecting fuel into the combustion chamber; the top wall of the piston is provided with a flow guide and heat insulation structure, the flow guide and heat insulation structure comprises a first flow guide wall, a flow dividing part and a second flow guide wall which are sequentially connected, and the flow dividing part is configured to be capable of dividing a fuel beam injected by the fuel injector towards the flow dividing part so that part of fuel can flow along the first flow guide wall, and the other part of fuel can flow along the second flow guide wall. In addition, a groove is formed in the first flow guide wall, part of the fuel flowing along the first flow guide wall can continue flowing in the current movement direction when passing through the groove, the part of the fuel cannot enter the groove, and therefore a layer of air heat insulation area is formed in the groove. And the wall surface heat transfer loss of the groove wall position of the groove is reduced.

Description

TECHNICAL FIELD

[0001] The utility model relates to the technical field of engine, especially piston and engine. BACKGROUND

[0002] The combustion chamber of the engine is formed by the top wall of the piston, the inner wall of the cylinder head and the inner wall of the cylinder body, and the oil injector is used to spray fuel into the combustion chamber. Figure 1 As shown in the figure, the top wall of the piston 1000 is part of the combustion chamber cavity wall, and the oil injector 2000 is used to spray fuel beam into the combustion chamber, specifically, the fuel beam is sprayed towards the protrusion 1001 of the top wall of the piston 1000, and under the diversion effect of the protrusion 1001, it is divided into two parts, one part flows along the top wall of the piston 1000 towards the outer wall of the piston 1000, and the other part flows along the top wall of the piston 1000 towards the center of the piston 1000. However, this scheme has two problems, one of which is that the oil injector 2000 has upper and lower oil injection holes, and only one protrusion 1001 cannot match the two oil injection holes, which will cause the fuel sprayed by at least one oil injection hole to be unable to be effectively diverted, making it difficult to mix with fresh air uniformly; the other problem is that after the fuel is diverted by the protrusion 1001, the two parts of the fuel flow along the top wall of the piston 1000, which causes a large amount of heat to be conducted to the piston 2000, thereby increasing the heat transfer of the piston 1000, reducing the energy converted into useful work, and causing economic deterioration.

[0003] In view of the problem that only one protrusion cannot match the two oil injection holes of the oil injector, the prior art provides a combustion chamber, the top wall of the piston of which is provided with an upper throat and a lower throat at the same time, the upper throat is used to match the upper layer of the oil injection hole, and the lower throat is used to match the lower layer of the oil injection hole, so that the upper throat and the lower throat respectively divert the fuel beams sprayed by the upper and lower layers of the oil injection hole, so that they can be mixed with air uniformly, but it also has the problem that after the fuel is diverted, the two parts of the fuel will flow along the top wall of the piston, which causes a large amount of heat to be conducted to the piston, thereby increasing the heat transfer of the piston, reducing the energy converted into useful work, and causing economic deterioration. UTILITY MODEL CONTENTS

[0004] According to one aspect of the utility model, the utility model provides a piston to solve the problem in the prior art that after the fuel is diverted, the two parts of the fuel will flow along the top wall of the piston, which causes a large amount of heat to be conducted to the piston, thereby increasing the heat transfer of the piston, reducing the energy converted into useful work, and causing economic deterioration.

[0005] In order to achieve the above purpose, the utility model adopts the following technical scheme:

[0006] A piston, a top wall of the piston being capable of surrounding a combustion chamber with an inner wall of a cylinder head and an inner wall of a cylinder body, the cylinder head being connected with an oil injector, the oil injector being used for injecting fuel into the combustion chamber;

[0007] The top wall of the piston has a flow guide and heat insulation structure, the flow guide and heat insulation structure comprising a first flow guide wall, a flow distribution part and a second flow guide wall connected in sequence, the flow distribution part being configured to be capable of distributing a fuel beam injected by the oil injector towards the flow distribution part, so that part of the fuel flows along the first flow guide wall and another part of the fuel flows along the second flow guide wall, the first flow guide wall being provided with a groove.

[0008] As a preferred scheme of the piston, the flow distribution part is a flow distribution protrusion, two ends of the flow distribution protrusion being connected with the first flow guide wall and the second flow guide wall respectively, the flow distribution protrusion extending towards the combustion chamber relative to the first flow guide wall and the second flow guide wall.

[0009] As a preferred scheme of the piston, the first flow guide wall is located at a side of the flow distribution part away from the cylinder head, and the first flow guide wall is arc-shaped.

[0010] As a preferred scheme of the piston, the flow distribution part is a flow distribution wall, two ends of the flow distribution wall being connected with the first flow guide wall and the second flow guide wall respectively.

[0011] As a preferred scheme of the piston, the first flow guide wall is located at a side of the flow distribution part close to the cylinder head, and the fuel flowing along the first flow guide wall is capable of flowing towards the inner wall of the cylinder head and being distributed by the inner wall of the cylinder head, so that part of the fuel flows towards the center of the cylinder head and another part of the fuel flows towards the outer periphery of the cylinder head.

[0012] As a preferred scheme of the piston, the first flow guide wall further has an end part flow distribution protrusion, the groove being located between the flow distribution part and the end part flow distribution protrusion, the fuel distributed by the inner wall of the cylinder head and flowing towards the outer periphery of the cylinder head is capable of flowing to the end part flow distribution protrusion and being distributed by the end part flow distribution protrusion, so that part of the fuel flows into the groove and another part of the fuel flows along the top wall of the piston towards the outer periphery of the cylinder head.

[0013] As a preferred scheme of the piston, the top wall has two flow guide and heat insulation structures, the second flow guide walls of the two flow guide and heat insulation structures being connected.

[0014] As a preferred scheme of the piston, the first flow guide wall has a connecting wall, the connecting wall connecting a side wall of the groove close to the flow distribution part, and an included angle between the side wall of the groove close to the flow distribution part and the connecting wall is not more than 90°.

[0015] According to another aspect of the utility model, provide engine, including above -mentioned piston, still include cylinder and fuel injector, the cylinder includes cylinder cover and the cylinder body connected to cylinder cover, the inner wall of piston's top wall, cylinder cover and the inner wall of cylinder body enclose combustion chamber, the fuel injector is used for injecting fuel to combustion chamber.

[0016] As the preferred scheme of engine, the fuel injector has upper layer fuel injection port and lower layer fuel injection port, the top wall has two flow guide heat insulation structures, the upper layer fuel injection port can inject fuel beam to the flow division part of one of the flow guide heat insulation structures, and the lower layer fuel injection port can inject fuel beam to the flow division part of another flow guide heat insulation structure.

[0017] The utility model has the advantages that:

[0018] The utility model provides a piston, its top wall can enclose combustion chamber with the inner wall of cylinder cover and the inner wall of cylinder body, cylinder cover connects fuel injector, and the fuel injector is used for injecting fuel to combustion chamber, the top wall of piston has flow guide heat insulation structure, and the flow guide heat insulation structure includes first flow guide wall, flow division part and second flow guide wall connected in proper order, the flow division part is configured to be able to shunt the fuel beam that fuel injector is injected towards flow division part, to make part of fuel flow along first flow guide wall, and another part of fuel flow along second flow guide wall, thereby make fuel beam be shunted and partially flow, make fuel can be mixed with air uniformly, in addition, first flow guide wall is provided with recess, and part of fuel that flows along first flow guide wall will keep the current direction of movement and continue to flow when passing through recess, and will not enter recess, thereby make a layer of air insulation zone be formed at recess, reduce the wall surface heat loss of the position of recess wall, thereby avoid fuel economy deterioration.

[0019] The utility model also provides engine, including above -mentioned piston, still include cylinder and fuel injector, the cylinder includes cylinder cover and the cylinder body connected to cylinder cover, the inner wall of piston's top wall, cylinder cover and the inner wall of cylinder body enclose combustion chamber, the fuel injector is used for injecting fuel to combustion chamber, wherein the fuel beam that fuel injector injects is shunted and partially flow, make fuel can be mixed with air uniformly, in addition, part of fuel that flows along first flow guide wall will keep the current direction of movement and continue to flow when passing through recess, and will not enter recess, thereby make a layer of air insulation zone be formed at recess, reduce the wall surface heat loss of the position of recess wall, thereby avoid fuel economy deterioration. ACCURACY OF DRAWINGS

[0020] Figure 1 It is the structure schematic view of piston and fuel injector in prior art;

[0021] Figure 2 It is the first structure schematic view of piston, cylinder cover and cylinder body in the utility model embodiment;

[0022] Figure 3 is Figure 2 is an enlarged view of A in the middle;

[0023] Figure 4 is a second structural schematic view of the piston, the cylinder cover and the cylinder body in the embodiment of the utility model;

[0024] Figure 5 is a third structural schematic view of the piston, the cylinder cover and the cylinder body in the embodiment of the utility model.

[0025] in the figure:

[0026] 1000, piston; 1001, protrusion; 2000, oil sprayer;

[0027] 100, combustion chamber; 101, heat insulation area; 110, cylinder cover; 120, cylinder body;

[0028] 200, top wall; 210, flow guide heat insulation structure;

[0029] 1, first flow guide wall; 11, connecting wall;

[0030] 2, flow distribution part;

[0031] 3, second flow guide wall;

[0032] 4, groove;

[0033] 5, end flow protrusion; 51, extension wall. DETAILED DESCRIPTION

[0034] The utility model will be further described in detail below in combination with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the utility model and are not limited to the utility model. In addition, it should be noted that, in order to facilitate the description, only the part related to the utility model is shown in the drawings and not all structures.

[0035] In the description of the utility model, unless otherwise explicitly specified and limited, the terms "connected", "connected", "fixed" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrated; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium; it can be the internal communication of two elements or the interaction relationship of two elements. For ordinary skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0036] In the utility model, unless another definite provision and limitation, first feature is in second feature "on" or "under" can include first and second feature direct contact, also can include first and second feature is not direct contact but is through their between another feature contact.

[0037] In the description of the embodiment, the terms "upper", "lower", "left", "right" and other orientation or position relationship are based on the orientation or position relationship shown in the drawings, only for the convenience of description and simplification operation, and do not indicate or imply that the device or element referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the utility model. In addition, the terms "first", "second" are only used to distinguish in the description, and have no special meaning.

[0038] In the conventional scheme, the top wall of the piston is part of the combustion chamber cavity wall, and the oil injector is used to spray a fuel beam to the combustion chamber, specifically, the fuel beam is sprayed towards the convex of the top wall of the piston, and is divided into two parts under the diversion of the convex, one part flows along the top wall of the piston towards the outer wall of the piston, and the other part flows along the top wall of the piston towards the center of the piston, but one of the problems is that the two parts of fuel flow along the top wall of the piston after being divided, resulting in a large amount of heat being conducted to the piston, and in turn increasing the heat transfer amount of the piston, reducing the energy converted into useful work, and causing economic deterioration.

[0039] To this end, the embodiment provides a piston to solve the problem in the prior art that after the fuel is divided, the two parts of fuel will flow along the top wall of the piston, resulting in a large amount of heat being conducted to the piston, and in turn increasing the heat transfer amount of the piston, reducing the energy converted into useful work, and causing economic deterioration, which can be used in the field of engine technology.

[0040] With reference to Figures 2-5The top wall of the piston can surround the combustion chamber 100 together with the inner wall of the cylinder head 110 and the inner wall of the cylinder body 120, the cylinder head 110 is connected with an oil injector for injecting fuel into the combustion chamber 100, in the embodiment, the fuel is diesel, and the piston is used in a diesel engine. The top wall 200 of the piston has a flow guide and heat insulation structure 210, which comprises a first flow guide wall 1, a flow distribution part 2 and a second flow guide wall 3 connected in sequence, the flow distribution part 2 is configured to distribute the fuel beam injected by the oil injector towards the flow distribution part 2, so that part of the fuel flows along the first flow guide wall 1 and another part of the fuel flows along the second flow guide wall 3, thereby the fuel beam is distributed by the flow distribution part 2, and the fuel can be uniformly mixed with air. In addition, the first flow guide wall 1 is provided with a groove 4, and the part of the fuel flowing along the first flow guide wall 1 will continue to flow in the current direction when passing through the groove 4 without entering the groove 4, so that an air heat insulation zone is formed at the groove 4, the wall surface heat loss of the groove wall position of the groove 4 is reduced, and the fuel economy is improved.

[0041] The piston is a rotary body, Figure 2 、 Figure 4 and Figure 5 Only half of the structure of the piston is shown. The first flow guide wall 1, the flow distribution part 2 and the second flow guide wall 3 of the flow guide and heat insulation structure 210 are arranged around the axis of the piston, and the oil injector is arranged at the center line position of the combustion chamber 100, a plurality of oil injection holes of the oil injector are arranged at intervals in the circumferential direction and are used for uniformly injecting the fuel beam towards the flow distribution part 2 around the oil injector.

[0042] It can be understood that, during the operation of the engine, the piston can reciprocate relative to the cylinder, and the oil injector of the embodiment sprays the fuel beam towards the flow distribution part 2, which means that the time and duration of the oil injection of the oil injector are set according to the position of the piston movement or the crank angle based on the actual needs of the engine operation, and during the period of oil injection, the fuel beam is directly sprayed towards the flow distribution part 2.

[0043] Continuing to refer to Figures 2-5 The first flow guide wall 1 has a connecting wall 11 connecting the side wall of the groove 4 close to the flow distribution part 2, and the included angle between the side wall of the groove 4 close to the flow distribution part 2 and the connecting wall 11 is not more than 90°, so that the included angle between the connecting wall 11 and the side wall of the groove 4 close to the flow distribution part 2 is small, which can reduce the amount of fuel flowing along the connecting wall 11 towards the groove 4.

[0044] The flow distribution part 2 has the following two possible structures:

[0045] One of them is as follows Figure 2As shown, the flow divider 2 is a flow divider protrusion. The two ends of the flow divider protrusion are connected to the first guide wall 1 and the second guide wall 3 respectively. The flow divider protrusion extends into the combustion chamber 100 relative to the first guide wall 1 and the second guide wall 3. That is, the flow divider 2 is protruding relative to the first guide wall 1 and the second guide wall 3. The flow divider protrusion guides part of the fuel to move towards the first guide wall 1 and guides another part of the fuel to move towards the second guide wall 3.

[0046] Optionally, the first guide wall 1 is located on the side of the split section 2 away from the cylinder head 110, that is, the first guide wall 1 is located on the side of the split section 2 close to the piston axis. The fuel flowing along the first guide wall 1 flows towards the direction close to the piston axis. The fuel injector is set on the piston axis, and the fuel injection port is generally located diagonally above the split section 2 and can inject fuel towards the split section 2. Since the split section 2 is a protrusion, and the protruding part needs to be set directly opposite the fuel injection port, the first guide wall 1 connected to the split section 2 will extend towards the deeper part of the piston. The first guide wall 1 also needs to be connected to the center part of the piston. Therefore, the flow path of the fuel flowing along the first guide wall 1 is relatively long. In order to reduce the flow resistance of the fuel, the first guide wall 1 is arc-shaped and smoothly transitions as a whole, so that the flow path of this part of the fuel is also arc-shaped, reducing the flow resistance. In addition, this can also increase the overall depth of the piston to adapt to the capacity requirements of the combustion chamber 100.

[0047] Another one is like Figures 2-3 As shown, the flow divider 2 is a flow divider wall. The two ends of the flow divider wall are connected to the first guide wall 1 and the second guide wall 3, respectively. That is, the flow divider 2 no longer protrudes relative to the first guide wall 1 and the second guide wall 3. The fuel jet is directly sprayed onto the flow divider wall and is divided, so that part of the fuel moves toward the first guide wall 1 and the other part of the fuel moves toward the second guide wall 3.

[0048] Optionally, the first guide wall 1 is located on the side of the split section 2 near the cylinder head 110, and the fuel flowing along the first guide wall 1 can flow toward the inner wall of the cylinder head 110 and be split by the inner wall of the cylinder head 110, so that a part of the fuel flows toward the center of the cylinder head 110 and another part of the fuel flows toward the outer periphery of the cylinder head 110, thereby further improving the fluidity of the fuel and further mixing the fuel with air.

[0049] Optionally, the first flow guide wall 1 further has an end portion flow protrusion 5, the groove 4 is located between the flow distribution portion 2 and the end portion flow protrusion 5, and the fuel flowing towards the outer periphery of the cylinder head 110 after being distributed by the inner wall of the cylinder head 110 can flow to the end portion flow protrusion 5 and be distributed by the end portion flow protrusion 5, so that part of the fuel flows into the groove 4, and the other part of the fuel flows along the top wall 200 of the piston towards the outer periphery of the cylinder head 110. In this way, after being distributed by the flow distribution portion 2, part of the fuel flows along the first flow guide wall 1 to the inner wall of the cylinder head 110, and after being distributed by the inner wall of the cylinder head 110, part of the fuel flows to the end portion flow protrusion 5 and is distributed by the end portion flow protrusion 5, so that part of the fuel flows into the groove 4, and the flow rate of the fuel flowing into the groove 4 is already low, and at this time, an air insulation region can also be formed in the groove 4.

[0050] In the embodiment, the top wall 200 has two flow guide insulation structures 210, and the second flow guide walls 3 of the two flow guide insulation structures 210 are connected. One of the flow guide insulation structures 210 has a flow distribution protrusion as the flow distribution portion 2, and the other flow guide insulation structure 210 has a flow distribution wall as the flow distribution portion 2. In the direction from the outer periphery of the piston to the axis, the two flow guide insulation structures 210 connected in sequence on the top wall 200 are arranged close to the outer periphery of the piston, and the end portion flow protrusion 5, the groove wall of the groove 4, the first flow guide wall 1, the flow distribution wall, and the second flow guide wall 3 are sequentially connected. The other flow guide insulation structure 210 is arranged close to the axis of the piston, and the second flow guide wall 3, the flow distribution protrusion, the first flow guide wall 1, and the groove wall of the groove 4 are sequentially connected.

[0051] Referring to Figure 4 In the flow guide insulation structure 210 close to the outer periphery of the piston, the end portion flow protrusion 5 is connected to the end of the outer periphery of the top wall 200 through an extension wall 51, and the angle between the extension wall 51 and the cylinder head 110 is θ, 8°≤θ≤16°. In the radial direction of the piston, the extension wall 51 is inclined towards the direction close to the cylinder head 110, so as to increase the depth of the combustion chamber 100 as much as possible, and the value of θ can be 8°, 9°, 10°, 11°, 12°, 13°, 14°, 15°, or 16°.

[0052] The distance between the end of the extension wall 51 away from the end portion flow protrusion 5, i.e., the connection between the extension wall 51 and the end of the outer periphery of the top wall 200 and the axis of the piston is D1, and 0.86D≤D1≤0.93D, where D is the radius of the inner wall of the cylinder body 120, and D1 can be used to represent the maximum radius of the combustion chamber 100, and the value of D1 can be 0.86D, 0.87D, 0.88D, 0.89D, 0.9D, 0.91D, 0.92D, or 0.93D.

[0053] The distance between the end portion flow protrusion 5 and the piston axis is D2, 0.72D≤D2≤0.88D, and D2<D1, and the value of D2 can be specifically 0.72D, 0.73D, 0.74D, 0.75D, 0.76D, 0.77D, 0.78D, 0.79D, 0.8D, 0.81D, 0.82D, 0.83D, 0.84D, 0.85D, 0.86D, 0.87D, or 0.88D.

[0054] The groove wall of the groove 4 close to one side of the end portion flow protrusion 5 is in a circular arc shape, and the radius is d1, 0.02D≤d1≤0.04D, and the value of d1 can be specifically 0.02D, 0.03D, or 0.04D. The maximum distance between the groove wall of the groove 4 and the cylinder cover 110 is H1, 0.05D≤H1≤0.08D, and the value of H1 can be specifically 0.05D, 0.06D, 0.07D, or 0.08D.

[0055] The groove wall of the groove 4 close to one side of the first flow guide wall 1 is in a circular arc shape, and the radius is d2, and the value of d2 can be obtained according to the simulation analysis result.

[0056] The flow distribution wall is vertically arranged with the cylinder cover 110, and the distance between the flow distribution wall and the piston axis is D3, 0.6D≤D3≤0.65D, and the value of D3 can be specifically 0.6D, 0.61D, 0.62D, 0.63D, 0.64D, or 0.65D.

[0057] The second flow guide walls 3 of the two flow guide heat insulation structures 210 are connected and integrally form a circular arc, and the radius of the circular arc is d3, 0.11D≤d3≤0.16D, and the value of d3 can be specifically 0.11D, 0.12D, 0.13D, 0.14D, 0.15D, or 0.16D.

[0058] Continuing to refer to Figure 4 , in the flow guide heat insulation structure 210 close to the piston axis, the flow distribution protrusion is in a circular arc shape, and the radius is d4, 0.04D≤d4≤0.06D, and the value of d4 can be specifically 0.04D, 0.05D, or 0.06D.

[0059] The distance between one end of the flow distribution protrusion close to the piston axis and the piston axis is D4, 0.5D≤D4≤0.6D, and D4<D3, and the value of D4 can be specifically 0.5D, 0.51D, 0.52D, 0.53D, 0.54D, 0.55D, 0.56D, 0.57D, 0.58D, 0.59D, or 0.6D.

[0060] The distance between the end of the flow splitting protrusion close to the piston axis and the cylinder head 110 is H2, 0.13D≤H2≤0.18D, and H2 can be specifically 0.13D, 0.14D, 0.15D, 0.16D, 0.17D or 0.18D.

[0061] The first flow guide wall 1 is in the shape of a circular arc with a radius d5, 0.04D≤d5≤0.07D, and d5 can be specifically 0.04D, 0.05D, 0.06D or 0.07D.

[0062] The maximum distance between the first flow guide wall 1 and the cylinder head 110 is H, which can be used to represent the maximum depth of the combustion chamber 100, 0.22D≤H≤0.28D, and H can be specifically 0.22D, 0.23D, 0.24D, 0.25D, 0.26D, 0.27D or 0.28D.

[0063] The arc-shaped transition between the connecting wall 11 and the groove wall of the groove 4 has a radius d6, and d6 satisfies Re>300, where Re is the Reynolds number, and the calculation formula is:

[0064]

[0065] where ρ is the density of diesel, U is the average speed of diesel flowing across the arc between the connecting wall 11 and the groove wall of the groove 4, and μ is the dynamic viscosity of diesel. When the Reynolds number Re is greater than 300, the diesel near-wall boundary layer will separate and fall off, periodic vortex shedding will occur at the connection between the connecting wall 11 and the groove wall of the groove 4, the turbulence intensity at the bottom of the groove 4 will be increased, thereby promoting the mixing of fuel and air and improving the diesel combustion heat release rate peak, as shown in Figure 5 .

[0066] The distance between the end point of the groove wall of the groove 4 close to the connecting wall 11 and the piston axis is D5, 0.25D≤D5≤0.3D, and D5 can be specifically 0.25D, 0.26D, 0.27D, 0.28D, 0.29D or 0.3D.

[0067] The groove wall of the groove 4 away from the connecting wall 11 is in the shape of an arc with a radius d7, and the value of d7 can be obtained according to the simulation analysis result.

[0068] The central part of the top wall 200, i.e. the part of the top wall 200 close to the axis, is connected with the groove wall of the groove 4, specifically, the part of the top wall 200 close to the axis and the connecting wall 11 are respectively connected with the two ends of the groove wall of the groove 4, and the part of the top wall 200 close to the axis is also arc-shaped with a radius d8, 0.25D≤d8≤0.35D, and the value of d8 can be specifically 0.25D, 0.26D, 0.27D, 0.28D, 0.29D, 0.3D, 0.31D, 0.32D, 0.33D, 0.34D or 0.35D.

[0069] The embodiment also provides an engine, which comprises the piston, further comprises a cylinder and an oil injector, the cylinder comprises a cylinder head 110 and a cylinder body 120 connected to the cylinder head 110, the top wall 200 of the piston, the inner wall of the cylinder head 110 and the inner wall of the cylinder body 120 form a combustion chamber 100, and the oil injector is used for injecting fuel into the combustion chamber 100. The fuel beam injected by the oil injector is divided by the dividing part 2, so that the fuel can be uniformly mixed with air, and in addition, part of the fuel flowing along the first flow guide wall 1 continues to flow while maintaining the current direction of movement when passing through the groove 4, so that an air heat insulation zone is formed at the groove 4, the heat transfer loss of the wall surface at the position of the groove wall of the groove 4 is reduced, and the fuel economy is prevented from deteriorating.

[0070] Optionally, the oil injector has an upper oil injection port and a lower oil injection port, and the top wall 200 has two flow guide and heat insulation structures 210, the upper oil injection port can inject a fuel beam to the dividing part 2 of one of the flow guide and heat insulation structures 210, and the lower oil injection port can inject a fuel beam to the dividing part 2 of the other flow guide and heat insulation structure 210. Specifically, the time and duration of fuel injection of the oil injector can be set according to the position of piston movement or the crank angle based on the actual needs of engine operation.

[0071] The fuel amount injected by the upper oil injection port and the fuel amount injected by the lower oil injection port can be obtained through simulation analysis or calculation according to actual needs, and in the embodiment, the fuel amount injected by the upper oil injection port is 35-50% of the total fuel injection amount, and the fuel amount injected by the lower oil injection port is 50-65% of the total fuel injection amount.

[0072] Obviously, the above-mentioned embodiments of the utility model are only examples for clearly explaining the utility model, and are not the limitation of the embodiments of the utility model. For ordinary skilled in the art, various obvious changes, re-adjustment and replacement can be carried out without departing from the protection scope of the utility model. Here, it is unnecessary and impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the utility model should be included in the protection scope of the utility model claim.

Claims

1. An engine characterized by, The piston, the cylinder and the fuel injector, the inner wall of the top wall (200) of the piston, the inner wall of the cylinder head (110) and the inner wall of the cylinder body (120) form a combustion chamber (100), the cylinder head (110) is connected with the fuel injector, and the fuel injector is used for injecting fuel into the combustion chamber (100); The top wall (200) of the piston has a flow guide and heat insulation structure (210), the flow guide and heat insulation structure (210) comprises a first flow guide wall (1), a flow distribution part (2) and a second flow guide wall (3) connected in sequence, the flow distribution part (2) is configured to be capable of distributing the fuel jet injected by the fuel injector towards the flow distribution part (2), so that part of the fuel flows along the first flow guide wall (1) and another part of the fuel flows along the second flow guide wall (3), and the first flow guide wall (1) is provided with a groove (4). The fuel injector has an upper layer fuel injection port and a lower layer fuel injection port, the top wall (200) has two flow guide and heat insulation structures (210), the upper layer fuel injection port is capable of injecting a fuel jet towards the flow distribution part (2) of one of the flow guide and heat insulation structures (210), and the lower layer fuel injection port is capable of injecting a fuel jet towards the flow distribution part (2) of the other flow guide and heat insulation structure (210).

2. The engine of claim 1, wherein The flow distribution part (2) is a flow distribution protrusion, two ends of the flow distribution protrusion are connected with the first flow guide wall (1) and the second flow guide wall (3) respectively, and the flow distribution protrusion extends towards the combustion chamber (100) relative to the first flow guide wall (1) and the second flow guide wall (3).

3. The engine of claim 2, wherein, The first flow guide wall (1) is located on the side of the flow distribution part (2) away from the cylinder head (110), and the first flow guide wall (1) is arc-shaped.

4. The engine of claim 1, wherein The flow distribution part (2) is a flow distribution wall, two ends of the flow distribution wall are connected with the first flow guide wall (1) and the second flow guide wall (3) respectively.

5. The engine of claim 4, wherein, The first flow guide wall (1) is located on the side of the flow distribution part (2) close to the cylinder head (110), and the fuel flowing along the first flow guide wall (1) is capable of flowing towards the inner wall of the cylinder head (110) and being distributed by the inner wall of the cylinder head (110), so that part of the fuel flows towards the center of the cylinder head (110) and another part of the fuel flows towards the outer periphery of the cylinder head (110).

6. The engine of claim 5, wherein, The first flow guide wall (1) further has an end part flow distribution protrusion (5), the groove (4) is located between the flow distribution part (2) and the end part flow distribution protrusion (5), the fuel distributed by the inner wall of the cylinder head (110) and flowing towards the outer periphery of the cylinder head (110) is capable of flowing to the end part flow distribution protrusion (5) and being distributed by the end part flow distribution protrusion (5), so that part of the fuel flows into the groove (4) and another part of the fuel flows along the top wall (200) of the piston towards the outer periphery of the cylinder head (110).

7. The engine of any one of claims 1-6, wherein, The top wall (200) has two flow guide and heat insulation structures (210), and the second flow guide walls (3) of the two flow guide and heat insulation structures (210) are connected.

8. The engine of any one of claims 1-6, wherein, The first flow guide wall (1) has a connecting wall (11) connecting the side wall of the groove (4) near the shunt (2), and the included angle between the side wall of the groove (4) near the shunt (2) and the connecting wall (11) is not more than 90°.

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