Piston of internal combustion engine

Abstract

The internal combustion engine piston comprises a piston body, an inner cooling oil cavity is formed in the piston body, a groove is formed in the top of the inner cooling oil cavity and extends upwards from the top of the inner cooling oil cavity, the groove is filled with a heat conduction block, and the heat conduction block is used for conducting heat of the part, located above the inner cooling oil cavity, of the piston body to the inner cooling oil cavity. The heat conductivity of the heat conduction block is higher than that of the piston body, so that more heat is transferred to the inner cooling oil cavity from the top of the piston in unit time, the heat transfer speed of the heat of the part, located above the inner cooling oil cavity, of the piston body to the inner cooling oil cavity is increased, the heat taking efficiency of engine oil is improved, and the piston cooling capacity of the inner cooling oil cavity is improved. The problems of abnormal temperature of the piston, carbon deposition, clamping stagnation of movement of the ring group and the like are avoided, and heat dissipation of the piston in the movement process is met.

Description

TECHNICAL FIELD

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

[0002] The temperature of the piston top combustion chamber is a key to evaluate the reliability of the piston. In the related art, the cooling of the internal combustion engine piston is mainly through the internal cooling oil cavity inside the piston, and the heat of the combustion chamber and the ring groove of the piston is taken away by the flowing oil in the internal cooling oil cavity through heat conduction.

[0003] With higher demands on the performance indicators such as power of the internal combustion engine, the in-cylinder combustion environment becomes more severe, the in-cylinder pressure, combustion temperature and other values increase, and the thermal load increases. In order to ensure the normal operation of the internal combustion engine, avoid the coking of the oil in the internal cooling oil cavity and the ring groove, and prevent the occurrence of problems such as abnormal piston temperature, carbon deposition and ring set movement stagnation, higher requirements are put forward for the heat dissipation capacity of the piston during operation.

[0004] Therefore, how to improve the heat dissipation capacity of the piston has become a technical problem to be solved by the person skilled in the art. CONTENT OF THE UTILITY MODEL

[0005] The present application provides an internal combustion engine piston to improve the heat dissipation capacity of the piston.

[0006] In order to achieve the above purpose, the present application provides an internal combustion engine piston, comprising a piston body, an internal cooling oil cavity is formed in the piston body, a groove extending upward from the top of the internal cooling oil cavity is arranged at the top of the internal cooling oil cavity, a heat conduction block is filled in the groove, the heat conduction block is used for conducting heat of the part of the piston body above the internal cooling oil cavity to the internal cooling oil cavity, and the thermal conductivity of the heat conduction block is greater than that of the piston body.

[0007] Preferably, in the above internal combustion engine piston, the height of the top end of the groove is equal to or less than the height of the throat of the piston body.

[0008] Preferably, in the above internal combustion engine piston, the groove is arranged at the middle part between a ring groove of the piston body and the throat of the piston body; and / or, the width of the groove is less than or equal to half of the width of the internal cooling oil cavity.

[0009] Preferably, in the above internal combustion engine piston, the width of the end of the groove away from the internal cooling oil cavity is less than the width of the end of the groove close to the internal cooling oil cavity.

[0010] Preferably, in the above internal combustion engine piston, the groove is a ring-shaped groove, and the ring-shaped groove is formed along the circumference of the piston body.

[0011] Preferably, in the above-mentioned internal combustion engine piston, the inner cooling oil chamber comprises an annular oil chamber, an oil inlet channel and an oil outlet channel, the inlet of the oil inlet channel is in a trumpet shape, and the larger-diameter end of the trumpet shape is farther away from the annular oil chamber than the smaller-diameter end of the trumpet shape.

[0012] Preferably, in the above-mentioned internal combustion engine piston, the oil inlet channel is located at the portion of the annular oil chamber corresponding to the main thrust side of the piston body.

[0013] Preferably, in the above-mentioned internal combustion engine piston, the width of the portion of the annular oil chamber corresponding to the main thrust side of the piston body is greater than the width of the portion of the annular oil chamber corresponding to the secondary thrust side of the piston body.

[0014] Preferably, in the above-mentioned internal combustion engine piston, the annular oil chamber is located between a ring groove of the piston body and a three-ring groove of the piston body.

[0015] Preferably, in the above-mentioned internal combustion engine piston, the annular oil chamber is in an elongated shape in the cross section parallel to the axis direction of the piston body.

[0016] The internal combustion engine piston provided by the embodiment of the present application comprises a piston body, and an inner cooling oil chamber is formed in the piston body. A groove is arranged at the top of the inner cooling oil chamber, and the groove extends upward from the top of the inner cooling oil chamber. A heat-conducting block is filled in the groove, and the heat-conducting block is used to conduct heat from the portion of the piston body above the inner cooling oil chamber to the inner cooling oil chamber. The heat conductivity of the heat-conducting block is higher than the thermal conductivity of the piston body, so that more heat can be transferred from the top of the piston to the inner cooling oil chamber per unit time. The heat transfer speed of the heat from the portion of the piston body above the inner cooling oil chamber to the inner cooling oil chamber is improved, the efficiency of heat removal by oil is improved, the cooling capacity of the inner cooling oil chamber for the piston is improved, the problems such as abnormal temperature of the piston, carbon deposition and jamming of ring set movement are avoided, and the heat dissipation of the piston during movement is met. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some examples or embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creating any creative labor, and the present application can also be applied to other similar scenarios according to the provided drawings. Unless it is obvious from the language environment or otherwise stated, the same reference numerals in the drawings represent the same structure or operation.

[0018] Figure 1 is a structural schematic diagram of the internal combustion engine piston of the present application;

[0019] Figure 2is a partial sectional view of an internal combustion engine piston according to the present application;

[0020] Figure 3 is a structural schematic view of an internal cooling oil cavity of an internal combustion engine piston according to the present application.

[0021] The accompanying drawings are described as follows:

[0022] 1-piston body; 11-throat; 12-a ring groove; 2-internal cooling oil cavity; 21-groove; 22-annular oil cavity; 23-oil inlet passage; 24-oil outlet passage; 3-heat conduction block. DETAILED DESCRIPTION

[0023] The present application will be further described below in conjunction with the drawings and embodiments. It can be understood that the specific embodiments described herein are only used to explain the related application, but not to limit the application. The described embodiments are only a part of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts fall within the scope of protection of the present application.

[0024] It should be noted that, for the convenience of description, only the parts related to the application are shown in the drawings. The embodiments in the present application and the features in the embodiments can be combined with each other arbitrarily without conflict, as long as the combined technical features are not contradictory. All the feasible feature combinations are the technical contents explicitly described herein. Any one of the multiple features contained in the same sentence can be applied independently, and does not have to be applied together with other features.

[0025] As shown in the present application and claims, unless the context clearly indicates otherwise, the words “one”, “an”, “a”, and / or “the” do not specifically refer to the singular, but also include the plural. Generally speaking, the terms “comprise” and “include” only indicate the inclusion of the steps and elements explicitly identified, and these steps and elements do not constitute an exclusive list, and the method or device can also include other steps or elements. The element defined by the sentence “comprises a” does not exclude the presence of another identical element in the process, method, product or device comprising the element.

[0026] In the description of the embodiments of the present application, “ / ” represents or, unless otherwise specified, for example, A / B can represent A or B; “and / or” herein is only a description of the association between the associated objects, which means that there can be three relationships, for example, A and / or B can represent: A alone, A and B together, and B alone. In addition, in the description of the embodiments of the present application, “multiple” means two or more than two.

[0027] The piston comprises a piston top, a piston head and a piston skirt, wherein the piston top bears gas pressure and, together with the cylinder cover and the cylinder wall, forms a combustion chamber, the shape, position and size of which are related to the specific form of the combustion chamber; the piston head refers to the part above the ring groove piston pin hole, the piston head has multiple ring grooves for mounting piston rings, and the diesel engine has a high compression ratio, generally four ring grooves, namely a ring groove, a two-ring groove, a three-ring groove and a four-ring groove, the upper three ring grooves are used to mount gas rings, and the lower ring groove is used to mount an oil ring; the piston head conducts heat downward from the piston top to the cooling wall surface of the cylinder through the piston rings, thereby preventing the temperature of the piston top from being too high; the piston skirt refers to the part from the lower end surface of the four-ring groove to the lowermost end of the piston, including the piston pin hole for mounting the piston pin.

[0028] Please refer to Figures 1-3 .

[0029] The application discloses an internal combustion engine piston, comprising a piston body 1, an inner cooling oil cavity 2 is arranged in the piston body 1, the inner cooling oil cavity 2 is a cavity penetrating through the piston top, comprising an oil inlet channel 23, an annular oil channel and an oil return channel, engine oil is sprayed out by an oil sprayer, enters the annular oil channel from the oil inlet channel 23, oscillates reciprocatingly in the annular oil channel along the up-down movement of the piston body 1, simultaneously takes away the heat of the piston body 1, plays a cooling role on the piston, and finally the engine oil is discharged through the oil return channel.

[0030] In the scheme, a groove 21 is arranged at the top of the inner cooling oil cavity 2, the groove 21 extends upward from the top of the inner cooling oil cavity 2, a heat-conducting block 3 is filled in the groove 21, the heat-conducting block 3 is used for conducting heat of the part above the inner cooling oil cavity 2 of the piston body 1 to the inner cooling oil cavity 2, the thermal conductivity of the heat-conducting block 3 is higher than that of the piston body 1, so that more heat is transferred from the piston top to the inner cooling oil cavity 2 per unit time, the heat transfer speed of the heat of the part above the inner cooling oil cavity 2 of the piston body 1 to the inner cooling oil cavity 2 is improved, the heat taking away efficiency of the engine oil is improved, the cooling capacity of the inner cooling oil cavity 2 for the piston is improved, problems such as abnormal temperature of the piston, carbon deposition and ring set movement jam are avoided, and the heat dissipation of the piston in the movement process is met. Optionally, the heat-conducting block 3 is a copper alloy or other metal with good thermal conductivity.

[0031] Here, the position of the piston top of the piston is the upper end of the piston, the position of the piston skirt of the piston is the lower end of the piston, the top of the inner cooling oil cavity 2 is one end of the inner cooling oil cavity 2 close to the piston top of the piston body 1, and the groove 21 extends upward from the top of the inner cooling oil cavity 2, that is, the groove 21 extends from the inner cooling oil cavity 2 to the direction of the piston top.

[0032] The shape of the heat-conducting block 3 is matched with the shape of the groove 21, the heat-conducting block 3 fills the whole groove 21, the heat-conducting block 3 is close to the groove wall of the groove 21, and the heat of the piston body 1 is directly transmitted to the heat-conducting block 3; the inner cooling oil cavity 2 is communicated with the groove 21, and the heat-conducting block 3 located in the groove 21 can be directly contacted with the engine oil of the inner cooling oil cavity 2, so that the engine oil directly takes away the heat conducted by the heat-conducting block 3.

[0033] In the scheme, the heat-conducting block 3 is filled in the groove 21, the heat-conducting block 3 can support the groove wall of the groove 21, and the problem of the strength reduction of the piston body 1 caused by the opening of the groove 21 is reduced.

[0034] As shown in Figure 1 and Figure 2 , the groove 21 is opened along the vertical direction.

[0035] In some embodiments, the height of the top end of the groove 21 is equal to or less than the height of the throat 11 of the piston body 1, the length of the groove 21 is as long as possible, the heat transfer speed of the part of the piston body 1 between the throat 11 of the piston body 1 and the inner cooling oil cavity 2 is accelerated, and the temperature of the part of the piston body 1 between the throat 11 of the piston body 1 and the inner cooling oil cavity 2 is reduced.

[0036] The height of the top end of the groove 21 does not exceed the height of the throat 11 of the piston body 1, the cooling demand of the piston body 1 can be met, and the influence on the overall strength of the piston body 1 is reduced.

[0037] In some embodiments, the groove 21 is opened in the middle part between the ring groove 12 of the piston body 1 and the throat 11 of the piston body 1, so that the opening of the groove 21 does not excessively affect the strength of the piston body 1.

[0038] Further, the groove 21 is opened in the middle part between the ring groove 12 of the piston body 1 and the throat 11 of the piston body 1 and is close to the position of the ring groove 12 of the piston body 1, so that the heat of the piston body 1 close to the ring groove 12 is more conducted on the basis of ensuring the strength of the piston body 1, and the risk of carbon deposition in the ring groove 12 is reduced.

[0039] In the scheme, the width of the groove 21 is less than the width of the inner cooling oil cavity 2, in some embodiments, the width of the groove 21 is less than or equal to half of the width of the inner cooling oil cavity 2, the cooling effect of the piston body 1 is enhanced on the basis of not excessively affecting the strength of the piston body 1. Optionally, the width of the groove 21 is at least 2 mm, so as to reduce the risk of stress concentration.

[0040] It should be noted that the width of the inner cooling oil chamber 2 is the dimension of the inner cooling oil chamber 2 in the direction perpendicular to the axis of the piston body 1, and the width of the groove 21 is also the dimension perpendicular to the extension direction of the groove 21, and the extension direction of the groove 21 is the direction from the end of the groove 21 communicating with the inner cooling oil chamber 2 to the straight line where the top end of the groove 21 is located.

[0041] The width of the end of the groove 21 away from the inner cooling oil chamber 2 is smaller than the width of the end of the groove 21 close to the inner cooling oil chamber 2, so that the cross section of the groove 21 in the direction parallel to the axis of the piston body 1 is tapered, and correspondingly, the cross section of the heat conduction block 3 in the direction parallel to the axis of the piston body 1 is also tapered.

[0042] The cross section of the groove 21 and the heat conduction block 3 is tapered, which can reduce the matching difficulty of the groove 21 and the heat conduction block 3 on the one hand, and can increase the contact area of the heat conduction block 3 and the oil in the inner cooling oil chamber 2 on the other hand, further improving the cooling effect on the piston, and on the third aspect, it can also reduce the influence on the strength of the part of the piston body 1 close to the piston top end.

[0043] The design of the heat conduction block 3 changes the heat transfer path of the throat 11 of the combustion chamber to the annular groove 12, more heat is absorbed by the top of the heat conduction block 3 and conducted to other areas of the heat conduction block 3, thereby generating a new heat affected zone around the heat conduction block 3, achieving the goal of reducing the temperature of the annular groove 12, which helps to improve the reliability of the piston.

[0044] The inner cooling oil chamber 2 is an annular oil chamber, and the shape of the groove 21 is the same as that of the inner cooling oil chamber 2, which is an annular groove, and the groove 21 is arranged along the circular ring where the annular oil chamber is located, so as to form a continuous heat conduction structure in the piston body 1, and ensure the temperature balance of each position in the circumferential direction of the piston body 1.

[0045] The inner cooling oil chamber 2 includes an annular oil chamber 22, an oil inlet channel 23 and an oil outlet channel 24, and the groove 21 can be discontinuously distributed along the circumferential direction of the annular oil chamber 22, and the top ends of adjacent grooves 21 are communicated through flow channels to prevent dead corners from being formed in the grooves 21. Since the temperature of the main thrust side of the piston body 1 is higher than that of the auxiliary thrust side of the piston body 1, optionally, the number of grooves 21 arranged on the main thrust side of the piston body 1 can be greater than that of the grooves 21 arranged on the auxiliary thrust side of the piston body 1, and the total area of the grooves 21 arranged on the main thrust side of the piston body 1 is greater than that of the grooves 21 arranged on the auxiliary thrust side of the piston body 1.

[0046] In some embodiments, as shown in Figure 3 The inlet of the oil inlet channel 23 is in the shape of a horn, and the horn-shaped inlet has an end with a larger diameter and an end with a smaller diameter, and the end with a larger diameter of the horn-shaped inlet is away from the annular oil chamber 22 relative to the end with a smaller diameter of the horn-shaped inlet.

[0047] The larger end of the trumpet-shaped inlet is opposite the oil nozzle, facilitating more oil sprayed by the oil nozzle to enter the oil inlet 23, and then enter the annular oil gallery, increasing the amount of oil supplied to the inner cooling oil chamber 2 per unit time. Increasing the amount of oil entering the inner cooling oil chamber 2 increases the amount of oil in the inner cooling oil chamber 2 for cooling, enhancing the cooling effect of the inner cooling oil chamber 2 on the piston body 1.

[0048] The oil enters the oil inlet 23 through the trumpet mouth, and then enters the annular oil chamber 22 through the oil inlet 23. With the rapid and high-frequency up-and-down movement of the piston body 1, the oil continuously collides with the upper and lower wall surfaces of the inner cooling oil chamber 2 under the action of inertial force. Heat is transferred from the high-temperature area to the low-temperature area in the form of heat conduction. The high-temperature area is mainly concentrated in the throat 11 of the combustion chamber of the piston and the top surface of the piston. The heat is conducted downward, sequentially passing through the land, the ring groove, and the piston skirt.

[0049] Generally, the oil inlet 23 is arranged on the main thrust side of the piston body 1. Because the main thrust side is the exhaust end, the temperature of the main thrust side is high. Spraying the oil supplied through the oil inlet 23 at a lower temperature on the main thrust side at a higher temperature helps to better reduce the temperature of the piston.

[0050] The oil return gallery and the oil inlet 23 can be symmetrically distributed on both sides of the annular oil gallery, or can not be symmetrically distributed with the oil inlet 23. The position of the oil return gallery is not specifically limited in the present scheme, and those skilled in the art can design the position of the oil return gallery according to actual needs.

[0051] In some embodiments, the width of the annular oil chamber 22 is equal in the circumferential direction of the piston body 1.

[0052] In other embodiments, the width of the portion of the annular oil chamber 22 corresponding to the main thrust side of the piston body 1 is greater than the width of the portion of the annular oil chamber 22 corresponding to the secondary thrust side of the piston body 1.

[0053] The oil enters the portion of the annular oil chamber 22 corresponding to the main thrust side of the piston body 1 through the oil inlet 23, and then enters the portion of the annular oil chamber 22 corresponding to the secondary thrust side of the piston body 1. The oil entering the portion of the annular oil chamber 22 corresponding to the secondary thrust side of the piston body 1 has absorbed a part of the heat. This embodiment accelerates the flow rate of the oil in the portion of the annular oil chamber 22 corresponding to the secondary thrust side of the piston body 1 by reducing the width of the portion of the annular oil chamber 22 corresponding to the secondary thrust side of the piston body 1, to improve the heat exchange effect on the secondary thrust side of the piston body 1.

[0054] Optionally, the inner cooling oil chamber 2 is integrally formed with the groove 21.

[0055] In some embodiments, the annular oil chamber 22 is located between a ring groove 12 and a three-ring groove of the piston body 1 to cool the portion of the piston body 1 between the ring groove 12 and the three-ring groove. The annular oil chamber 22 is formed in a position of the piston body 1 with high strength, and the size of the annular oil chamber 22 can be relatively large to ensure the cooling effect of the piston body 1.

[0056] As shown in Figs. 1 and 2, the annular oil chamber 22 is in the shape of a long strip in a cross section parallel to the axis of the piston body 1, and the upper end and the lower end of the annular oil chamber 22 are both arc-shaped to increase the heat exchange area of the annular oil chamber 22. Figure 1 Figure 2 As shown in Figs. 1 and 2, the annular oil chamber 22 is in the shape of a long strip in a cross section parallel to the axis of the piston body 1, and the upper end and the lower end of the annular oil chamber 22 are both arc-shaped to increase the heat exchange area of the annular oil chamber 22.

[0057] The top of the annular oil chamber 22 is lower than the ring groove 12, and the bottom of the annular oil chamber 22 is higher than the three-ring groove.

[0058] The above description is merely preferred embodiments of the present application and the technical principles used, and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. The scope of the present application is not limited to the technical solutions formed by the specific combinations of the above technical features, and should also cover other technical solutions formed by any combinations of the above technical features or equivalent features without departing from the above application concept. For example, the above features can be replaced with the technical features disclosed in the present application (but not limited to) with similar functions to form technical solutions.​

Claims

1. An internal combustion engine piston characterized by, The piston body (1) is internally provided with an inner cooling oil cavity (2), the top of the inner cooling oil cavity (2) is provided with a groove (21) extending upward from the top of the inner cooling oil cavity (2), the groove (21) is filled with a heat-conducting block (3), the heat-conducting block (3) is used for conducting heat of the part of the piston body (1) above the inner cooling oil cavity (2) to the inner cooling oil cavity (2), and the thermal conductivity of the heat-conducting block (3) is greater than that of the piston body (1).

2. The internal combustion engine piston of claim 1, wherein The height of the top end of the groove (21) is equal to or less than the height of the throat (11) of the piston body (1).

3. The internal combustion engine piston of claim 1, wherein The groove (21) is arranged at the middle part between the ring groove (12) of the piston body (1) and the throat (11) of the piston body (1); and / or, the width of the groove (21) is less than or equal to half of the width of the inner cooling oil cavity (2).

4. The internal combustion engine piston of claim 1, wherein The width of the end of the groove (21) away from the inner cooling oil cavity (2) is less than the width of the end of the groove (21) close to the inner cooling oil cavity (2).

5. The internal combustion engine piston of any one of claims 1-4, wherein, The groove (21) is an annular groove, which is arranged along the circumferential direction of the piston body (1).

6. The internal combustion engine piston of any one of claims 1-4, wherein, The inner cooling oil cavity (2) comprises an annular oil cavity (22), an oil inlet channel (23) and an oil outlet channel (24), the inlet of the oil inlet channel (23) is in a trumpet shape, and the end with a larger diameter of the trumpet shape is away from the annular oil cavity (22) relative to the end with a smaller diameter of the trumpet shape.

7. The internal combustion engine piston of claim 6, wherein The oil inlet channel (23) is located at the part of the annular oil cavity (22) corresponding to the main thrust side of the piston body (1).

8. The internal combustion engine piston of claim 7, wherein The width of the part of the annular oil cavity (22) corresponding to the main thrust side of the piston body (1) is greater than the width of the part of the annular oil cavity (22) corresponding to the auxiliary thrust side of the piston body (1).

9. The internal combustion engine piston of claim 6, wherein, The annular oil cavity (22) is located between the ring groove (12) of the piston body (1) and the three-ring groove of the piston body (1).

10. The internal combustion engine piston of claim 6, wherein The annular oil cavity (22) is in a strip shape in the cross section parallel to the axis direction of the piston body (1).

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