Internal combustion engine

Abstract

An internal combustion engine includes a cylinder in which a piston reciprocates, a stepped portion formed on an upper end portion of an inner peripheral surface of the cylinder, and a ring member provided to the stepped portion and having a cylindrical shape. A thickness of the ring member decreases toward a center of a bottom portion of the piston, and an outer peripheral surface of the ring member is an inclined surface in which a lower end of the outer peripheral surface is positioned closer to a center in a radial direction of the ring member than an upper end of the outer peripheral surface.

Description

Technical Field

[0001] This disclosure relates to internal combustion engines, including cylinders and pistons. Background Technology

[0002] In internal combustion engines, a ring member is provided on the stepped portion of the upper part of the inner circumferential surface of the cylinder. For example, Japanese Unexamined Patent Application Publication No. 2017-089410 discloses an internal combustion engine in which an oil scraper ring is provided on the stepped portion to remove soot and grease adhering to the piston.

[0003] Existing technology

[0004] Patent documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2017-089410 Summary of the Invention

[0006] The problem to be solved by the present invention

[0007] In internal combustion engines, minimizing heat loss is desirable. However, when the ring components are located in the upper part of the cylinder, it is difficult to maintain a high temperature inside the combustion chamber due to the heat loss caused by the ring components.

[0008] This disclosure is made in view of these points, and its purpose is to provide an internal combustion engine that can reduce heat loss even when ring components are provided.

[0009] The means to solve this problem

[0010] In one aspect of this disclosure, an internal combustion engine is provided, comprising: a cylinder in which a piston reciprocates; a stepped portion formed at an upper end of an inner peripheral surface of the cylinder; and a ring member disposed in the stepped portion, having a cylindrical shape, wherein the thickness of the ring member decreases toward the bottom dead center of the piston, and the outer peripheral surface of the ring member is an inclined surface, wherein the lower end of the outer peripheral surface is closer to the center of the ring member in the radial direction than the upper end of the outer peripheral surface.

[0011] Furthermore, the inner circumferential surface of the step portion can be an inclined surface parallel to the outer circumferential surface, which is the inclined surface of the ring member.

[0012] In addition, the thickness of the lower end of the ring member can be equal to or less than half the thickness of the upper end of the ring member.

[0013] In addition, the inner circumferential surface of the ring component can be mirrored.

[0014] In addition, the internal combustion engine may also include an injector for injecting fuel, wherein, in the ring member, the thickness of a plurality of injection target portions, which are the portions of fuel to be injected into the injector, may be less than the thickness of other portions.

[0015] In addition, the spray target portion can be a portion on the outer peripheral surface of the ring member that has a recessed portion.

[0016] In addition, multiple protrusions can be formed on the inner circumferential surface of the cylinder, and the protrusions cooperate with the corresponding recesses of each injection target part.

[0017] Furthermore, the recessed portion may be a curved groove, and the protruding portion may have a curved protruding shape.

[0018] Furthermore, the minimum thickness in the recessed portion can be less than half the thickness of the other parts of the ring member.

[0019] In addition, the spray target portion can be a portion with a recessed portion formed on the inner circumferential surface of the ring member.

[0020] Effects of the present invention

[0021] According to this disclosure, even with the inclusion of ring components, heat loss in an internal combustion engine can be reduced. Attached Figure Description

[0022] Figure 1 This is a schematic diagram showing the internal configuration of an internal combustion engine 1 according to an embodiment.

[0023] Figure 2 This is a schematic diagram showing an internal combustion engine 100 according to a comparative example.

[0024] Figure 3 This is a schematic diagram illustrating an improved example of internal combustion engine 1. Detailed Implementation

[0025] <International Internal Combustion Engine Configuration>

[0026] Reference Figure 1 Describe the configuration of an internal combustion engine according to an implementation method.

[0027] Figure 1 This is a schematic diagram showing the internal configuration of an internal combustion engine 1 according to an embodiment. Figure 1 The diagram shows only a portion of the internal combustion engine 1, and other components have been omitted for ease of explanation.

[0028] An internal combustion engine 1 is, for example, an engine installed in a vehicle. Figure 1 As shown, the internal combustion engine 1 includes a cylinder 10, a piston 15, a stepped portion 20, a cylinder head 25, a gasket 30, and a ring member 40.

[0029] The cylinder 10 is made of metal and formed into a cylindrical shape. The piston 15 is housed in the cylinder 10.

[0030] Piston 15 reciprocates between top dead center and bottom dead center in cylinder 10. Figure 1 In the middle, piston 15 is located at top dead center. Piston ring 16 is fitted into a groove formed on the outer peripheral surface of piston 15.

[0031] like Figure 1 As shown, the stepped portion 20 is located at the upper end of the inner circumferential surface 11 of the cylinder 10. When the piston 15 is at top dead center, the stepped portion 20 is located above the piston ring 16. The stepped portion 20 is formed such that it extends circumferentially into the ground along the inner circumference of the inner circumferential surface 11 of the cylinder 10. The stepped portion 20 is located below the gasket 30.

[0032] The stepped portion 20 has an inner circumferential surface 22, which is as follows: Figure 1 The inclined surface is shown. Here, the inner circumferential surface 22 is inclined in a straight line at a predetermined inclination angle. The inner circumferential surface 22 is inclined such that the inner circumferential surface 22 is closer to the center of the cylinder 10 the further it is towards the bottom surface of the inner circumferential surface 22.

[0033] The cylinder head 25 is located above the cylinder 10. The cylinder head 25 is made of metal, and for example, of the same material as the cylinder 10.

[0034] Gasket 30 is disposed between cylinder 10 and cylinder head 25. Gasket 30 has the function of enhancing the airtightness of cylinder 10.

[0035] like Figure 1 As shown, the ring member 40 is disposed in the stepped portion 20. Specifically, the ring member 40 is fitted into the stepped portion 20. The ring member 40 is formed in a cylindrical shape and covers the periphery of the piston 15 located at the top dead center. The ring member 40 is made of metal. Here, the ring member 40 is made of the same material as the cylinder 10, but is not limited thereto, and may be made of a different material than the cylinder 10.

[0036] The ring member 40 is configured to narrow the space between the cylinder 10 and the piston 15. In other words, the inner circumferential surface 41 of the ring member 40 is positioned closer to the outer circumferential surface of the piston 15 than the inner circumferential surface 11 of the cylinder 10. If the ring member 40 is not provided, the space between the inner circumferential surface 11 of the cylinder 10 and the outer circumferential surface of the piston 15 would ultimately be a useless space unused for combustion, thereby reducing combustion efficiency. On the other hand, if the ring member 40 is provided as in this embodiment, the useless space can be reduced, thereby increasing the compression ratio and improving fuel efficiency.

[0037] The inner circumferential surface 41 of the ring member 40 is parallel to the inner circumferential surface 11 of the cylinder 10, but the outer circumferential surface 42 of the ring member 40 is not parallel to the inner circumferential surface 11 of the cylinder 10. The outer circumferential surface 42 of the ring member 40 is an inclined surface, wherein the lower end of the outer circumferential surface 42 is positioned closer to the radial center of the ring member 40 than the upper end of the outer circumferential surface 42. The inclination angle of the outer circumferential surface 42 is the same as the inclination angle of the inner circumferential surface 22 of the stepped portion 20, and the outer circumferential surface 42 is parallel to the inner circumferential surface 22.

[0038] like Figure 1 As shown, the thickness of the ring member 40 decreases towards the bottom surface of the stepped portion 20. In other words, the thickness of the ring member 40 decreases towards the bottom dead center of the piston 15. Here, the thickness of the lower end of the ring member 40 is equal to or less than half the thickness of the upper end of the ring member 40. Figure 2 Compared to the comparative example shown, providing a ring member 40 with this thickness has advantages.

[0039] Figure 2 This is a schematic diagram showing an internal combustion engine 100 according to a comparative example. In the comparative example, the inner circumferential surface 141 and the outer circumferential surface 142 of the ring member 140 are parallel to each other, and the thickness of the ring member 140 is constant. Furthermore, the inner circumferential surface 122 of the stepped portion 120 is parallel to the inner circumferential surface 11 of the cylinder 10. With the ring member 140 provided, a certain amount of heat is lost due to the ring member 140 compared to the case without the ring member. Therefore, it is difficult to maintain a high temperature inside the cylinder 10.

[0040] Conversely, in this embodiment, the outer peripheral surface 42 of the ring member 40 is an inclined surface. Therefore, the thickness of the ring member 40 is not constant, meaning that the thickness of the ring member 40 decreases towards the bottom surface of the stepped portion 20. Specifically, the thickness at the lower end of the ring member 40 is equal to or less than half the thickness at the upper end. In this case, since the volume of the ring member 40 is smaller than that of the ring member 140 in the comparative example, the heat capacity of the ring member 40 is smaller. This allows the temperature of the ring member 40 to rise more easily and enhances the heat shielding effect while reducing heat loss.

[0041] Furthermore, when the outer peripheral surface 42 is an inclined surface, the area of ​​the outer peripheral surface 42 is larger than the area of ​​the outer peripheral surface 142 in the comparative example. That is, since the area of ​​the outer peripheral surface 42 facing the inner peripheral surface 22 of the stepped portion 20 is large, gas leakage can be prevented. In addition, since the outer peripheral surface 42 and the inner peripheral surface 22 of the stepped portion 20 are inclined surfaces, the ring member 40 can be easily assembled into the stepped portion 20.

[0042] The inner circumferential surface 41 of the ring member 40 is mirror-like, and the irregularity on the inner circumferential surface 41 is very small. For example, the arithmetic mean roughness, representing the surface roughness of the inner circumferential surface 41, is 0.1 μm or less. Because the inner circumferential surface 41 is mirror-like, putty can be prevented from adhering to the inner circumferential surface 41. This helps to reduce heat loss caused by heat absorption by the putty, thereby enhancing the thermal shielding effect in the cylinder 10. Conversely, if the inner circumferential surface were not mirror-like, putty might easily adhere to irregularities on the inner circumferential surface.

[0043] <Modification Example>

[0044] Figure 3 This is a schematic diagram illustrating a modified example of internal combustion engine 1. Figure 3 For ease of explanation, piston 15 and other details have been omitted.

[0045] The configuration of the ring member 40 and the inner circumferential surface 11 of the cylinder 10 in the modified example is... Figure 1 The ring member 40 and the inner circumferential surface 11 shown are configured differently. This is because the configuration of other components in the modified example differs from... Figure 1 The configurations shown are the same, so a detailed description of them will be omitted.

[0046] The internal combustion engine 1 includes an injector 60 for injecting fuel. For example, the injector 60 is located above the central axis of the cylinder 10 and injects fuel radially within the cylinder 10. The direction of fuel flow injected from the injector 60 is determined by… Figure 3 The area is indicated by a dashed line.

[0047] The width of the ring member 40 in the modified example is not constant. Specifically, as shown... Figure 3 As shown, in the annular member 40, the thickness of a plurality of injection target portions 45, which are portions of fuel to be injected into the injector 60, is smaller than the thickness of other portions. The injection target portions 45 are arranged at four positions at predetermined intervals in the circumferential direction of the annular member 40. The thickness of the portions other than the injection target portions 45 is constant.

[0048] A recessed portion 46 is formed on the outer peripheral surface 42 of the ring member 40. Here, the recessed portion 46 is a curved groove. The recessed portion 46 is formed at four locations on the outer peripheral surface 42 at predetermined intervals. The spray target portion 45 is the portion of the recessed portion 46 formed on the outer peripheral surface 42 of the ring member 40. Figure 3 As shown, the minimum thickness in the recessed portion 46 is less than half the thickness of the other portions of the ring member 40.

[0049] It should be noted that although the recessed portion 46 is formed on the outer peripheral surface 42 of the ring member 40 in the above description, the present disclosure is not limited thereto, and for example, the recessed portion may be formed on the inner peripheral surface 41 of the ring member 40.

[0050] By reducing the thickness of the spray target portion 45 of the ring member 40 as described above, the volume of the ring member 40 is further reduced, and the heat capacity of the ring member 40 is further reduced. This makes it easier for the temperature of the ring member 40 to rise, and even further enhances the heat shielding effect.

[0051] A plurality of protrusions 18 are formed on the inner circumferential surface 11 of the cylinder 10, and the protrusions 18 mate with the corresponding recesses 46 of each injection target portion 45. The protrusions 18 are arranged at four positions at predetermined intervals in the circumferential direction. Here, each protrusion 18 has a curved protruding shape. The protrusions 18 are fitted into the recesses 46 of the ring member 40. Therefore, when the ring member 40 is fitted into the stepped portion 20 of the cylinder 10, the injection target portion 45 can be positioned in the appropriate position. Furthermore, even if the ring member 40 attempts to rotate in the circumferential direction during the operation of the internal combustion engine 1, the mating recesses 46 and protrusions 18 also act as, for example, rotation stops.

[0052] <Effects of this implementation method>

[0053] The internal combustion engine 1 of the embodiments described above includes a ring member 40 having a cylindrical shape, which is disposed on a stepped portion 20 formed on the upper end portion of the inner peripheral surface 11 of the cylinder 10. The thickness of the ring member 40 decreases toward the bottom dead center of the piston 15, and the outer peripheral surface 42 of the ring member 40 is an inclined surface, wherein the lower end of the outer peripheral surface 42 is positioned closer to the radial center of the ring member 40 than the upper end of the outer peripheral surface 42.

[0054] When the ring member 40 has an inclined outer peripheral surface 42, the volume of the ring member 40 is reduced. Therefore, the heat capacity of the ring member 40 is reduced. As a result, the temperature of the ring member 40 tends to increase, and the heat shielding effect is enhanced while reducing heat loss.

[0055] This disclosure has been described based on exemplary embodiments. The technical scope of this disclosure is not limited to the scope described in the above embodiments, and various changes and modifications can be made within the scope of this disclosure. For example, all or part of the device may be configured with any functionally or physically separated or integrated units. Furthermore, new exemplary embodiments resulting from any combination thereof are included in the exemplary embodiments. Moreover, the effects of the new exemplary embodiments resulting from the combinations also have the effects of the original exemplary embodiments.

[0056] Description of reference numerals in the attached figures

[0057] 1. Internal Combustion Engine

[0058] 10 cylinders

[0059] 11 Inner peripheral surface

[0060] 18. Protruding part

[0061] 20 steps

[0062] 40 ring components

[0063] 41 Inner peripheral surface

[0064] 42 Peripheral surface

[0065] 45. Spray target section

[0066] 46. ​​Recessed portion

[0067] 60 injectors

Claims

1. An internal combustion engine, comprising: Cylinder, in which the piston reciprocates; The stepped portion is formed at the upper end of the inner circumferential surface of the cylinder; as well as The ring member, disposed in the stepped portion, has a cylindrical shape, wherein... The thickness of the ring member decreases toward the bottom dead center of the piston, and The outer peripheral surface of the ring member is an inclined surface, wherein the lower end of the outer peripheral surface is positioned closer to the radial center of the ring member than the upper end of the outer peripheral surface. The internal combustion engine also includes an injector that injects fuel, wherein... In the ring member, the thickness of a plurality of injection target portions, which are the portions to be injected with fuel from the injector, is smaller than the thickness of the other portions, and The spray target portion is formed at predetermined intervals along the circumferential direction of the ring member.

2. The internal combustion engine according to claim 1, wherein, The inner circumferential surface of the stepped portion is an inclined surface parallel to the outer circumferential surface, and the outer circumferential surface is the inclined surface of the ring member.

3. The internal combustion engine according to claim 1, wherein, The thickness of the lower end of the ring member is equal to or less than half the thickness of the upper end of the ring member.

4. The internal combustion engine according to claim 1, wherein, The inner circumferential surface of the ring component is a mirror surface.

5. The internal combustion engine according to claim 1, wherein, The spray target portion is the portion on the outer peripheral surface of the ring member that has a recessed portion.

6. The internal combustion engine according to claim 5, wherein, A plurality of protrusions are formed on the inner circumferential surface of the cylinder, the protrusions engaging with a corresponding recess of each of the injection target portions.

7. The internal combustion engine according to claim 6, wherein, The recessed portion is a curved groove, and The protruding portion has a curved protruding shape.

8. The internal combustion engine according to claim 5, wherein, The minimum thickness in the recessed portion is less than half the thickness of the other portions of the ring member.

9. The internal combustion engine according to claim 1, wherein, The spray target portion is the portion on the inner circumferential surface of the ring member that has a recessed portion.

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