Engine piston and engine

Abstract

The utility model discloses an engine piston and an engine, the engine piston comprises a piston body, a cooling oil cavity is formed in the piston body, the cooling oil cavity comprises an oil cavity body and an annular groove oil cavity, and the annular groove oil cavity is used for cooling the part, located between an annular groove of the piston body and the oil cavity body, of the piston body. According to the engine piston disclosed in the scheme, the structure of the cooling oil cavity is changed, on the basis of an original heat transfer path of the piston, the heat transfer path of the annular groove oil cavity is added, the overall heat exchange area of the cooling oil cavity is increased, the heat exchange efficiency of the piston body is improved, the annular land and the annular groove which are prone to carbon deposition are specifically cooled, and the service life of the piston body is prolonged. The risk of carbon deposition of a ring groove and a ring land is reduced; meanwhile, transfer of part of heat from the piston head to the ring groove and the ring land is cut off through the ring groove oil cavity, the heat transferred to the ring groove and the ring land is reduced, and the purpose that the temperature of the ring groove and the temperature of the ring land are reduced so as to reduce the carbon deposition risk of the ring groove and the ring land can be achieved.

Description

Technical Field

[0001] This application relates to the field of engine technology, and in particular to an engine piston and an engine. Background Technology

[0002] The temperature inside the combustion chamber is transferred sequentially through the piston top, the piston's first ring land, the first ring groove, the cooling oil chamber, and the piston bottom. In related technologies, piston cooling is mainly achieved through oil injection cooling.

[0003] like Figure 1 and Figure 2 As shown, the distance between the piston's cooling oil chamber 01 and the first ring groove 011 is relatively far. The cooling capacity of the cooling oil chamber 01 for the area above the first ring groove 011 is limited. There is a risk of carbon buildup in the piston's first ring groove 011 and first ring land 012. Carbon buildup will reduce the side clearance and back clearance of the piston ring located in the first ring groove 011, or even eliminate the clearance, causing the piston ring to stick, lose elasticity, and cause cylinder scoring, or even damage to this section of the piston ring.

[0004] Therefore, how to reduce the risk of carbon buildup in the piston's first ring groove and first ring land has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] This application discloses an engine piston designed to reduce the risk of carbon buildup on the piston's first annular groove and first annular land. This application also discloses an engine.

[0006] To achieve the above objectives, this application provides an engine piston, including a piston body, wherein a cooling oil chamber is formed within the piston body.

[0007] The cooling oil chamber includes an oil chamber body and an annular groove oil chamber communicating with the upper end of the oil chamber body. The annular groove oil chamber is used to cool the portion of the piston body located between an annular groove of the piston body and the oil chamber body of the piston body.

[0008] Preferably, in the engine piston described above, the height of the annular groove oil chamber does not exceed the upper edge of the annular groove.

[0009] Preferably, in the engine piston described above, the width of the annular groove oil cavity is less than or equal to the width of the annular groove, and the width of the annular groove oil cavity is ≥2mm.

[0010] Preferably, in the above-mentioned engine piston, the annular groove oil chamber is located in the middle between the throat of the piston body and an annular groove of the piston body.

[0011] Preferably, in the above-mentioned engine piston, the width of the portion of the annular groove oil cavity corresponding to the main thrust surface of the piston body is greater than the width of the portion of the annular groove oil cavity corresponding to the secondary thrust surface of the piston body.

[0012] Preferably, in the engine piston described above, the width of the annular groove oil cavity is equal or gradually decreases from the end communicating with the oil cavity body to the end away from the oil cavity body.

[0013] Preferably, in the above-mentioned engine piston, the annular groove oil chamber is an annular oil chamber.

[0014] Preferably, in the engine piston described above, the communication position between the annular groove oil chamber and the oil chamber body is close to the annular groove.

[0015] Preferably, in the above-mentioned engine piston, the inner wall of the end of the annular groove oil chamber away from the oil chamber body is arc-shaped.

[0016] An engine includes an engine piston, wherein the engine piston is the engine piston described in any of the above embodiments.

[0017] The engine piston provided in this application includes a piston body with a cooling oil chamber. The cooling oil chamber includes an oil chamber body and an annular groove oil chamber. The annular groove oil chamber is located at the upper end of the oil chamber body and communicates with it, serving to cool the portion of the piston body located between the annular groove and the oil chamber body. This engine piston alters the structure of the cooling oil chamber by adding the annular groove oil chamber as a heat transfer path to the original piston heat transfer path. The annular groove oil chamber increases the overall heat exchange area of ​​the cooling oil chamber, improving the heat exchange efficiency of the piston body. It also specifically cools the annular land and annular groove, which are prone to carbon buildup, reducing the risk of carbon buildup in these areas. Simultaneously, the annular groove oil chamber isolates some heat from the piston head to the annular groove and annular land, reducing the heat transferred to these areas and lowering their temperature, thus reducing the risk of carbon buildup.

[0018] This solution also discloses an engine, including an engine piston, which is the engine piston described in any of the above solutions. Since the engine piston has the aforementioned technical effects, the engine having this engine piston also has the same technical effects, and will not be elaborated further here. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort, and this application can be applied to other similar scenarios based on the provided drawings. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0020] Figure 1 This is a heat flow diagram of a piston in an existing engine.

[0021] Figure 2 It is a cross-sectional view of the cooling oil chamber of the piston in an existing engine.

[0022] Figure 3 This is a heat flow diagram of the engine piston in this application;

[0023] Figure 4 This is a cross-sectional view of the cooling oil chamber of the engine piston in this application;

[0024] Figure 5 This is a simulation comparison of engine piston temperatures before and after using this cooling solution for the oil chamber;

[0025] Figure 6 This is a simulation comparison of the fatigue safety factors of key parts of the engine piston before and after adopting this cooling oil chamber solution;

[0026] Figure 7 This is a simulation comparison diagram of the fatigue safety factor of the cooling oil chamber of the engine piston before and after adopting this solution.

[0027] The attached diagram is described below:

[0028] 01-Cooling oil chamber; 011-Annular groove; 012-Annular shore;

[0029] 1-Piston body; 11-Throat; 12-Annular groove; 2-Cooling oil chamber; 21-Oil chamber body; 22-Annular groove oil chamber; 23-Upper edge. Detailed Implementation

[0030] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. The described embodiments are only a part of the embodiments of the present application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are within the scope of protection of the present application.

[0031] It should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined, provided that the combined technical features are not contradictory. All feasible combinations of features are the technical content explicitly described herein. Any one of the multiple sub-features contained in the same statement can be applied independently, without necessarily being applied together with other sub-features.

[0032] As indicated in this application and claims, unless the context clearly indicates otherwise, the words "a," "an," "a," and / or "the" are not specifically singular and may include the plural. Generally, the terms "comprising" and "including" only indicate the inclusion of expressly identified steps and elements, which do not constitute an exclusive list, and the method or apparatus may also include other steps or elements. An element defined by the phrase "comprising an..." does not exclude the presence of other identical elements in the process, method, product, or apparatus that includes the element.

[0033] In the description of the embodiments of this application, unless otherwise stated, " / " means "or", for example, A / B can mean A or B; "and / or" in this document is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Furthermore, in the description of the embodiments of this application, "multiple" refers to two or more.

[0034] A piston consists of three parts: the piston crown, the piston head, and the piston skirt. The piston crown bears the gas pressure and, together with the cylinder head and cylinder wall, forms the combustion chamber. Its shape, position, and size are related to the specific form of the combustion chamber. The piston head refers to the part above the 12th piston pin hole. The piston head has multiple annular grooves for installing piston rings. Diesel engines have a high compression ratio and generally have four annular grooves: the 1st annular groove (12th), the 2nd annular groove, the 3rd annular groove, and the 4th annular groove. The upper three annular grooves are for installing compression rings, and the lower annular groove is for installing oil rings. The upper end of the 1st annular groove (12th) is the 1st annular land, the space between the 1st annular groove (12th) and the 2nd annular groove is the 2nd annular land, the space between the 2nd annular groove and the 3rd annular groove is the 3rd annular land, and the space between the 3rd annular groove and the 4th annular groove is the 4th annular land. The piston head conducts heat from the piston crown downwards through the piston rings to the cooling walls of the cylinder, thus preventing the piston crown from overheating. The piston skirt refers to the part from the lower end face of the 4th annular groove to the bottom of the piston, including the piston pin hole for installing the piston pin.

[0035] Please see Figures 1-7 .

[0036] Some embodiments of this application disclose an engine piston, including a piston body 1, a cooling oil chamber 2 is provided in the piston body 1, the cooling oil chamber 2 includes an oil chamber body 21 and an annular groove oil chamber 22, the annular groove oil chamber 22 is disposed at the upper end of the oil chamber body 21 and communicates with the oil chamber body 21, the annular groove oil chamber 22 is used to cool the part of the piston body 1 located between an annular groove 12 of the piston body 1 and the oil chamber body 21.

[0037] like Figure 3 As shown, the oil chamber body 21 is located between the second and fourth ring banks. The oil chamber body 21 cools the part of the piston body 1 located between the second and fourth ring banks. The oil chamber body 21 is located at a position where the piston body 1 has high strength. The size of the oil chamber body 21 can be designed to be relatively large to ensure the cooling effect on the piston body 1. The annular groove oil chamber 22 is located between the first annular groove 12 and the oil chamber body 21. The annular groove oil chamber 22 cools the part of the piston body 1 located between the first annular groove 12 and the oil chamber body 21.

[0038] The engine piston disclosed in this solution adds an annular groove oil chamber 22 to the original cooling oil chamber 2. The oil chamber body 21 is connected to the annular groove oil chamber 22, so that the engine oil enters the annular groove oil chamber 22 at the same time as entering the oil chamber body 21. The oil chamber body 21 and the annular groove oil chamber 22 play a cooling role at the same time, cooling the part of the piston body 1 located between the first annular groove 12 and the fourth annular land.

[0039] The cooling oil chamber 2 disclosed in this solution changes the structure of the piston cooling oil chamber 2 in related technologies. Based on the original heat transfer path of the piston, it adds a heat transfer path of annular groove oil chamber 22 from two aspects: increasing the heat exchange area of ​​cooling oil chamber 2 and blocking the heat transfer path. This significantly reduces the surface temperature of the throat 11 and annular groove 12 of the piston body 1 of the high power density engine. Specifically, the annular groove oil chamber 22 is located at the top of the oil chamber body 21, increasing the overall heat exchange area of ​​the cooling oil chamber 2 and improving the heat exchange efficiency of the piston body 1. It also specifically cools the first annular land and the first annular groove 12, which are prone to carbon buildup, reducing their temperature and thus lowering the risk of carbon buildup. The annular groove oil chamber 22 is located between the first annular groove 12 and the throat 11 of the piston body 1. Heat conducted from the piston head is first conducted to the annular groove oil chamber 22 before being conducted to the first annular groove 12 and the first annular land. The annular groove oil chamber 22 blocks some of the heat from the piston head to the first annular groove 12 and the first annular land, reducing the amount of heat transferred to the first annular groove 12 and the first annular land, thereby lowering their temperature and reducing the risk of carbon buildup. This, in turn, reduces engine cylinder scoring and improves engine reliability.

[0040] like Figure 2As shown, assuming the length of the oil chamber body 21 along the circumferential direction of the piston body 1 is L, the heat transfer area S of the piston's cooling oil chamber 2 in the prior art is S = L × (L1 + L2), where L1 + L2 is the perimeter of the cross-section of the cooling oil chamber 2 along the direction parallel to the piston's axis. Figure 2 The cooling oil chamber 2 is divided into two parts along the circumference of its cross-section parallel to the piston axis: L2 is the circumferential length of the cooling oil chamber 2 where it connects with the annular groove oil chamber 22, and L1 is the circumferential length of the cooling oil chamber 2 where it does not connect with the annular groove oil chamber 22. Figure 4 As shown, the heat exchange area S′ of the cooling oil chamber 2 disclosed in this solution is S′=L×(L1+ Ls), where Ls is the perimeter of the cross section of the annular groove oil chamber 22 along the direction parallel to the piston axis. The length of Ls is much greater than L2. The heat exchange area S′ of the cooling oil chamber 2 disclosed in this solution is greater than the heat exchange area S of the cooling oil chamber 2 in the prior art. Therefore, the heat exchange effect of the cooling oil chamber 2 of the engine piston disclosed in this solution is higher than the heat exchange effect of the cooling oil chamber 2 of the engine piston in the prior art.

[0041] In traditional high-power-density diesel engines, the piston throat 11 and the piston annular groove 12 typically operate around the limits of their allowable operating temperatures. This solution reduces the temperature of the piston body 1's throat 11 and annular groove 12, allowing them to operate within the limits of their allowable operating temperatures. This significantly improves the fatigue strength of the piston throat 11, noticeably delays the formation of carbon deposits in the piston annular groove 12, and enhances the lifespan and reliability of the piston in the high-power-density diesel engine.

[0042] In some embodiments, the height of the annular groove oil chamber 22 does not exceed the upper edge 23 of the annular groove 12, so that the annular groove oil chamber 22 can cool the portion of the piston body 1 located between the annular groove 12 and the oil chamber body 21.

[0043] This design incorporates an annular groove oil cavity 22 in the portion of the piston body 1 located between the annular groove 12 and the oil cavity body 21. This upward movement of the upper end of the cooling oil cavity 2 within the piston body 1 allows for targeted cooling of the portion of the piston body 1 located between the annular groove 12 and the oil cavity body 21, reducing the cooling limitations imposed on the throat 11 and the annular groove 12 of the piston body 1 due to their position. It should be noted that the upper edge 23 of the annular groove oil cavity 22 is the point on the piston body 1 that is furthest from the oil cavity body 21 along the axial direction of the piston body 1.

[0044] If the upper edge 23 of the annular groove oil chamber 22 is too high, it may cause insufficient strength of the piston body 1 in this part. The arc of the upper edge 23 of the annular groove oil chamber 22 should be controlled at 180° as much as possible.

[0045] The width of the annular groove oil cavity 22 is less than or equal to the width of the annular groove 12. The width of the annular groove oil cavity 22 is the dimension of the annular groove oil cavity 22 along the direction perpendicular to the axis of the piston body 1, and the width of the annular groove 12 is the dimension of the annular groove 12 along the direction perpendicular to the axis of the piston body 1.

[0046] The width of the annular groove oil cavity 22 is at least 2 mm and does not exceed the width of the annular groove 12. If the width of the annular groove oil cavity 22 is too small, it is easy to cause local stress concentration. If the width of the annular groove oil cavity 22 is too large, it is easy to cause insufficient strength of the piston body 1 at the position corresponding to the annular groove 12 and the throat 11.

[0047] Optionally, the width, height, and curvature of the upper edge 23 of the annular groove oil cavity 22 are optimized using precise simulation analysis techniques. This allows for the precise determination of the optimal height of L2 (arc length of the arc at the point where the annular groove oil cavity 22 connects to the oil cavity body 21), Ls (width of the cross-section at the end of the annular groove oil cavity 22 away from the oil cavity body 21), and the specific height of the upper edge 23. This achieves the goal of precise design while ensuring piston strength and reducing the temperature of the piston throat 11 and the annular groove 12.

[0048] The annular groove oil chamber 22 is located in the middle between the throat 11 of the piston body 1 and the annular groove 12 of the piston body 1, so as to ensure that the strength of the piston body 1 located on both sides of the annular groove oil chamber 22 is similar, and to reduce the impact of the opening of the annular groove oil chamber 22 on the strength of the piston body 1.

[0049] like Figure 5 The figure shows a piston temperature simulation diagram. It can be seen from the figure that the temperature of the throat 11 of the engine piston using the above-mentioned cooling oil chamber 2 is reduced by more than 10°C compared with the temperature of the throat 11 of the engine piston using the conventional cooling oil chamber 2, and the temperature of the first ring groove 12 of the engine piston is reduced by more than 15°C. The above data proves that the above-mentioned cooling oil chamber 2 can reduce the temperature of the throat 11 and the first ring groove 12 by at least 10°C.

[0050] Although this design provides an annular groove oil cavity 22 between the annular groove 12 of the piston body 1 and the oil cavity body 21, it does not significantly affect the strength of the piston throat 11 and the annular groove 12. Figure 6 As shown, the safety factor of the piston top and key parts of the cooling oil chamber 2 is slightly lower or higher than that of a traditional piston. However, for the newly added annular groove oil chamber 22, as... Figure 7 As shown, the upper part is relatively weak because the newly added annular groove oil chamber 22 is mainly under pressure. The safety factor is much greater than the design standard, and the fatigue strength of the piston meets the requirements.

[0051] Under normal circumstances, the oil inlet of the cooling oil chamber 2 is located on the main thrust side of the piston body 1. Since the main thrust side is the exhaust end, the temperature of the exhaust end is high. The oil with a lower temperature supplied through the oil inlet is sprayed onto the main thrust side with a higher temperature, which helps to better reduce the temperature of the piston.

[0052] The engine oil first enters the portion of the oil chamber body 21 corresponding to the main thrust side of the piston body 1 through the oil inlet passage, and then enters the portion of the oil chamber body 21 corresponding to the secondary thrust side of the piston body 1. The engine oil entering the portion of the oil chamber body 21 corresponding to the secondary thrust side of the piston body 1 has already absorbed some heat. This embodiment improves the heat exchange effect on the secondary thrust side of the piston body 1 by reducing the width of the portion of the oil chamber body 21 corresponding to the secondary thrust side of the piston body 1.

[0053] Optionally, the width of the portion of the annular groove oil cavity 22 corresponding to the main thrust surface of the piston body 1 is greater than the width of the portion of the annular groove oil cavity 22 corresponding to the secondary thrust surface of the piston body 1, so as to accelerate the flow speed of the oil in the annular groove oil cavity 22 corresponding to the secondary thrust surface of the piston body 1, thereby improving the heat exchange effect between the annular groove 12 and the oil cavity body 21 on the secondary thrust side of the piston body 1.

[0054] Optionally, the annular groove oil cavity 22 is integrally formed with the oil cavity body 21.

[0055] The width of the annular groove oil cavity 22 is equal or gradually decreases from the end connected to the oil cavity body 21 to the end away from the oil cavity body 21. While ensuring the strength of the piston body 1, it improves the cooling effect of the oil in the annular groove oil cavity 22 on the piston body 1.

[0056] The oil chamber body 21 is an annular oil chamber, and the shape of the annular groove oil chamber 22 can be the same as that of the oil chamber body 21, also being an annular oil chamber. The annular groove oil chamber 22 is arranged along the annulus where the oil chamber body 21 is located, so as to form a continuous cooling structure in the piston body 1 and ensure that the temperature of each position in the circumferential direction of the piston body 1 is uniform.

[0057] The oil chamber body 21 is an annular oil chamber, and the annular groove oil chambers 22 can be discontinuously distributed along the circumference of the oil chamber body 21. The tops of adjacent annular groove oil chambers 22 are connected through flow channels to prevent the oil from forming dead zones in the annular groove oil chambers 22. Since the temperature on the main thrust side of the piston body 1 is higher than the temperature on the secondary thrust side of the piston body 1, optionally, the number of annular groove oil chambers 22 provided on the main thrust side of the piston body 1 can be greater than the number of annular groove oil chambers 22 provided on the secondary thrust side of the piston body 1, and the total area of ​​the annular groove oil chambers 22 provided on the main thrust side of the piston body 1 is greater than the total area of ​​the annular groove oil chambers 22 provided on the secondary thrust side of the piston body 1.

[0058] like Figure 3 As shown, the cross-section of the oil cavity body 21 along the direction parallel to the axis of the piston body 1 is elongated, and both the upper and lower ends of the oil cavity body 21 are arc-shaped to increase the heat exchange area of ​​the oil cavity body 21.

[0059] The top of the oil cavity body 21 is lower than the first annular groove 12, and the bottom of the oil cavity body 21 is higher than the third annular groove.

[0060] The annular groove oil chamber 22 is connected to the oil chamber body 21 at a position close to the annular groove 12 of the piston body 1, so as to enhance the cooling effect of the annular groove oil chamber 22 on the position of the annular groove 12.

[0061] The inner wall of the end of the annular groove oil cavity 22 away from the oil cavity body 21 is arc-shaped to increase the contact area between the annular groove oil cavity 22 and the piston body 1 and improve the cooling effect.

[0062] This solution also discloses an engine, including an engine piston, which is the engine piston described in any of the above solutions.

[0063] Since the engine piston has the aforementioned technical effects, the engine with the same engine piston also has the same technical effects, which will not be elaborated further here.

[0064] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed, and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. The scope of this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described application concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An engine piston, characterized in that, It includes a piston body (1), and a cooling oil chamber (2) is provided inside the piston body (1). The cooling oil chamber (2) includes an oil chamber body (21) and an annular groove oil chamber (22) connected to the upper end of the oil chamber body (21). The annular groove oil chamber (22) is used to cool the portion of the piston body (1) located between an annular groove (12) of the piston body (1) and the oil chamber body (21) of the piston body (1). The oil inlet of the cooling oil chamber (2) is located on the main thrust side of the piston body (1). The oil chamber body (21) is located between the second and fourth ring banks. The oil chamber body (21) cools the part of the piston body (1) located between the second and fourth ring banks. The annular groove oil chamber (22) is located between the first annular groove (12) and the oil chamber body (21). The height of the annular groove oil chamber (22) does not exceed the upper edge (23) of the first annular groove (12). The width of the annular groove oil chamber (22) is less than or equal to the width of the first annular groove (12).

2. The engine piston according to claim 1, characterized in that, The width of the annular groove oil cavity (22) is ≥2mm.

3. The engine piston according to claim 1, characterized in that, The annular groove oil chamber (22) is located in the middle between the throat (11) of the piston body (1) and an annular groove (12) of the piston body (1).

4. The engine piston according to claim 1, characterized in that, The width of the portion of the annular groove oil cavity (22) corresponding to the main thrust surface of the piston body (1) is greater than the width of the portion of the annular groove oil cavity (22) corresponding to the secondary thrust surface of the piston body (1).

5. The engine piston according to claim 1, characterized in that, The width of the annular groove oil cavity (22) is equal or gradually decreases from the end connected to the oil cavity body (21) to the end away from the oil cavity body (21).

6. The engine piston according to claim 1, characterized in that, The annular groove oil cavity (22) is an annular oil cavity.

7. The engine piston according to claim 1, characterized in that, The annular groove oil cavity (22) is located close to the annular groove (12) in the communication position with the oil cavity body (21).

8. The engine piston according to claim 1, characterized in that, The inner wall of the end of the annular groove oil cavity (22) away from the oil cavity body (21) is arc-shaped.

9. An engine, characterized in that, Includes an engine piston, wherein the engine piston is the engine piston according to any one of claims 1-8.

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