Eccentric inner-cooling oil cavity piston

Abstract

The invention relates to the technical field of internal combustion engine pistons, in particular to an eccentric inner-cooling oil cavity piston, an eccentric combustion chamber is arranged at the top, the center line of the eccentric combustion chamber and the center line of the piston are offset by the distance L1, an inner-cooling oil cavity comprises an outer ring cavity and an inner ring cavity which are communicated with each other, and the center line of the outer ring cavity and the center line of the piston are collinear; the center line of the inner ring cavity and the center line of the eccentric combustion chamber are collinear. The weight of the piston can be effectively reduced, and the overall performance is improved. Meanwhile, the surface temperature of a piston combustion chamber part can be reduced, carbon deposition layers and oxide layers on the part are reduced, and the reliability and the service life of the piston are improved.

Description

Technical Field

[0001] The invention relates to the technical field of internal combustion engine pistons, and in particular to an eccentric inner-cooling oil cavity piston. Background Art

[0002] The piston is a component that reciprocates within the cylinder of an internal combustion engine. At top dead center, the piston's top surface, the cylinder, and the cylinder head together form the engine's combustion chamber. Fuel in the cylinder burns here, and this area is subject to high thermal loads. Excessive temperatures in the combustion chamber can easily lead to carbon deposits and ablation, significantly impacting the component's service life. To mitigate this risk, most pistons are equipped with an internal cooling oil chamber for forced cooling.

[0003] Most pistons currently on the market have their combustion chamber centerlines aligned with the piston centerline. However, some pistons have non-aligned combustion chambers (also known as eccentric combustion chambers), and the combustion chamber centerline is significantly offset from the piston centerline. This results in a smaller cooling chamber in the design of eccentric combustion chamber pistons, increasing piston weight. Furthermore, the wall thickness between the piston cooling chamber and the combustion chamber is uneven, leading to uneven cooling of the combustion chamber and uneven temperature distribution across the piston, significantly impacting piston reliability and service life.

[0004] To cope with increasing thermal and mechanical loads, the existing design of the internal cooling oil chamber for eccentric combustion chamber pistons aligns the centerline of the internal cooling oil chamber with the piston centerline, and the outer wall thickness of the internal cooling oil chamber is consistent with that of the piston ring land and ring groove. This results in uneven wall thickness between the inner wall of the internal cooling oil chamber and the combustion chamber, and the size of the internal cooling oil chamber is also limited.

[0005] For pistons with eccentric combustion chambers, according to existing design and manufacturing methods, the centerline of the piston's internal cooling oil cavity and the centerline of the piston's combustion chamber are not aligned. This leads to the following disadvantages: 1. The size of the piston's inner cooling oil cavity is greatly affected by the eccentricity of the combustion chamber. The overall size of the inner cooling oil cavity is relatively small, and the cooling capacity is insufficient, which has a significant negative impact on the overall cooling of the piston.

[0006] 2. The wall thickness between the cold oil cavity and the combustion chamber in the piston is uneven, resulting in uneven cooling of the combustion chamber where the temperature of the piston top surface is higher. Thick carbon deposits and oxide layers are easily formed locally, which has a great impact on the reliability and service life of the piston.

[0007] 3. The cold oil chamber in the piston is relatively small, the piston is heavy, and the energy loss in the engine is large, which affects the performance of the entire machine and cannot meet the lightweight design requirements of the piston. Summary of the Invention

[0008] In response to the shortcomings of the existing technology, the present invention provides an eccentric internal cooling oil chamber piston, which optimizes the internal cooling oil chamber structure of the eccentric combustion chamber piston, ensures that the cooling effect of the outer circumference of the internal cooling oil chamber of the piston on the ring land and the ring groove is consistent, and at the same time ensures the structural strength of the ring groove and the ring land, thereby improving the reliability and service life of the piston.

[0009] The present invention is achieved through the following technical solutions: An eccentric inner cooling oil chamber piston is provided, with an eccentric combustion chamber on the top. The centerline of the eccentric combustion chamber is offset from the centerline of the piston by a distance L1. The inner cooling oil chamber includes an outer ring cavity and an inner ring cavity that are interconnected. The centerline of the outer ring cavity is collinear with the centerline of the piston, and the centerline of the inner ring cavity is collinear with the centerline of the eccentric combustion chamber.

[0010] This solution optimizes the structure of the cooling oil chamber in the eccentric combustion chamber piston, dividing the inner cooling oil chamber into two parts: an inner ring chamber and an outer ring chamber. The centerline of the outer ring chamber is in a straight line with the centerline of the piston, and the centerline of the inner ring chamber is in a straight line with the centerline of the combustion chamber. The size of the inner cooling oil chamber is significantly increased, and the wall thickness from the inner cooling oil chamber to the combustion chamber is greatly reduced, thereby improving the cooling effect of the inner cooling oil chamber on the combustion chamber, and being able to meet the heat exchange requirements under the current high-strength index requirements of the engine; to a certain extent, it reduces the weight of the piston, reduces the energy loss during engine operation, and improves the engine performance.

[0011] Furthermore, the wall thicknesses L2 and L3 from the circumference of the inner ring cavity to the combustion chamber remain consistent, and the wall thicknesses L6 and L7 from the outer wall of the outer ring cavity to the piston ring groove remain consistent.

[0012] The wall thickness setting of the inner ring cavity of the eccentric inner cooling oil cavity ensures that the inner cooling oil cavity cools all parts of the piston combustion chamber, which can effectively reduce the temperature of the piston combustion chamber; the wall thickness setting of the outer ring cavity of the eccentric inner cooling oil cavity ensures that the inner cooling oil cavity cools the piston ring groove and ring land, which can effectively reduce the temperature of the piston ring land and ring groove, while ensuring the structural strength of the ring groove and ring land.

[0013] Furthermore, the annular upper wall of the inner cooling oil chamber is formed by a plane wall and curved walls located on both sides of the plane wall. The widths of the plane walls on both sides of the axis of the inner cooling oil chamber are L8 and L9 respectively, where: L8>L9>0, and (L8-L9) / 2=L1.

[0014] Beneficial effects of the present invention: The present invention optimizes the structure of the cooling oil chamber in the eccentric combustion chamber piston through design innovation, and divides the cooling oil chamber into two parts: an inner ring chamber and an outer ring chamber. The center line of the inner ring chamber is in a straight line with the center line of the piston, and the center line of the outer ring chamber is in a straight line with the center line of the combustion chamber. That is, this part of the cooling oil chamber maintains the same eccentric state as the eccentric combustion chamber, so that the size of the cooling oil chamber is significantly increased, and the wall thickness from the inner cooling oil chamber to the combustion chamber is greatly reduced, thereby improving the cooling effect of the cooling oil chamber on the combustion chamber, and can meet the heat exchange requirements of the current high-strength engine requirements, ensure that the outer circumferential side of the cooling oil chamber in the piston has the same cooling effect on the ring bank and the ring groove, and at the same time ensure the structural strength of the ring groove and the ring bank, and the wall thickness between the inner side of the cooling oil chamber and various parts of the combustion chamber is consistent, thereby ensuring uniform cooling of the entire combustion chamber and the ring bank.

[0015] The size of the internal cooling oil cavity of the present invention has been improved, which can effectively reduce the weight of the piston and improve the performance of the entire machine. At the same time, it can reduce the surface temperature of the piston combustion chamber, reduce the generation of carbon deposits and oxide layers in this area, reduce energy loss during engine operation, and improve engine performance. It is of great help to improve the thermal efficiency, economy, environmental protection and other indicators of the internal combustion engine, and can effectively improve the reliability and service life of the piston. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a cross-sectional schematic diagram of the eccentric inner cooling oil chamber piston of the present invention.

[0017] Figure 2 for Figure 1 Schematic cross-section of HH.

[0018] Figure 3 This is a three-dimensional view of the eccentric inner cooling oil chamber of the eccentric inner cooling oil chamber piston shown in the present invention.

[0019] Figure 4 It is a schematic cross-sectional perspective view of the eccentric inner cooling oil chamber piston of the present invention.

[0020] Figure 5 The present invention adopts FEA simulation analysis cloud map.

[0021] As shown in the figure: 1. Piston body, 2. Centerline of the piston, 3. Centerline of the eccentric combustion chamber, 4. Eccentric inner cooling oil cavity, 5. Outer ring cavity, 6. Inner ring cavity, 7. Eccentric combustion chamber, 8. Plane wall, 9. Curved wall. DETAILED DESCRIPTION

[0022] In order to clearly illustrate the technical features of this solution, this solution is described below through specific implementation methods.

[0023] like Figure 1-Figure 3As shown, an eccentric internal oil-cooling piston has an eccentric combustion chamber 7 on top. The centerline 3 of the eccentric combustion chamber is offset from the centerline 2 of the piston by a distance L1. The internal oil-cooling chamber includes an outer ring cavity 5 and an inner ring cavity 6 that are interconnected. The centerline of the outer ring cavity 5 is collinear with the centerline 2 of the piston, and the centerline of the inner ring cavity 6 is collinear with the centerline 3 of the eccentric combustion chamber. The offset distance L1 between the centerline 3 of the piston and the centerline 3 of the eccentric combustion chamber is not fixed and is related to the layout of the engine cylinder head, intake and exhaust valves, and injectors. Taking the injector as an example, when the injector position is set, the position of the combustion chamber on the piston is determined, that is, the injector is located on the centerline 3 of the eccentric combustion chamber. The offset distance L1 is the vertical distance between the injector and the centerline 2 of the piston.

[0024] like Figure 1 As shown, the annular upper wall of the inner cooling oil chamber is formed by a plane wall 8 and a curved wall 9 located on both sides of the plane wall 8. The widths of the plane wall 8 on both sides of the axis of the inner cooling oil chamber are L8 and L9 respectively, where: L8>L9>0, and (L8-L9) / 2=L1.

[0025] like Figure 1 As shown, the wall thickness L2 and L3 of the inner ring cavity from the circumference to the combustion chamber remain consistent, and the wall thickness L6 and L7 of the outer wall of the outer ring cavity from the piston ring groove remain consistent.

[0026] The piston of the present invention has an eccentric combustion chamber 7, the center line 3 of the eccentric combustion chamber 7 is offset from the center line 2 of the piston by a distance L1, the offset distance and direction are not fixed, and the piston material and forming method are not fixed; like Figure 2 As shown, the eccentric inner cooling oil chamber 4 is located at the head of the piston body 1. During operation, the engine oil is forced to be sprayed in the inner cooling oil chamber to cool the piston ring land and the combustion chamber. The eccentric inner cooling oil chamber 4 is composed of the outer ring chamber 5 and the inner ring chamber 6. The proportion of the outer ring chamber 5 and the inner ring chamber 6 in the entire eccentric inner cooling oil chamber 4 is not fixed. The processing and forming methods of the outer ring chamber 5 and the inner ring chamber 6 are not fixed. The three-dimensional shape of the eccentric inner cooling oil chamber 4 is as follows: Figure 3 shown.

[0027] The centerline of the inner cooling oil cavity outer ring cavity diameter L4 is in a straight line with the piston centerline 2. In this state, the eccentric inner cooling oil cavity 4 circumferentially to the piston ring groove wall thickness L6, L7 are equal.

[0028] The center line of the inner ring cavity 6 of the eccentric inner cooling oil chamber is in a straight line with the center line 3 of the combustion chamber, and the offset distance from the center line 2 of the piston is equal to the eccentric distance L1 of the combustion chamber. This ensures that the center line of the diameter L5 of the inner ring cavity of the inner cooling oil chamber is in a straight line with the center line 3 of the combustion chamber. In this state, the wall thickness L2 and L3 of the eccentric inner cooling oil chamber 4 from the circumference to the piston combustion chamber are equal.

[0029] The uniform wall thickness of the outer ring cavity of the eccentric inner cooling oil chamber 4 ensures that the inner cooling oil chamber cools the piston ring grooves and lands, effectively reducing the temperatures of the piston lands and grooves while also ensuring the structural strength of the grooves and lands. The uniform wall thickness of the inner side of the eccentric inner cooling oil chamber 4 ensures that the inner cooling oil chamber cools all parts of the piston combustion chamber, effectively reducing the temperature of the piston combustion chamber.

[0030] like Figure 5 As shown in the figure, the piston temperature is predicted by FEA simulation analysis. By analyzing the cloud map, we can see that the temperature distribution of the piston using the eccentric inner cooling oil cavity of the present invention is more uniform than that of the conventional inner cooling oil cavity piston, and the maximum temperature value is lower.

[0031] Of course, the above description is not limited to the above examples. Technical features not described in the present invention can be achieved by or by adopting existing technologies, which will not be described here. The above embodiments and drawings are only used to illustrate the technical solutions of the present invention and are not limitations of the present invention. The present invention is described in detail with reference to the preferred implementation methods. Ordinary technicians in this field should understand that changes, modifications, additions or substitutions made by ordinary technicians in this technical field within the essential scope of the present invention do not depart from the purpose of the present invention and should also fall within the scope of protection of the claims of the present invention.

Claims

1. An eccentric internally cooled oil chamber piston with an eccentric combustion chamber on top, characterized by: The centerline of the eccentric combustion chamber is offset from the centerline of the piston by a distance of L1. The inner cooling oil cavity includes an outer ring cavity and an inner ring cavity that are connected to each other. The centerline of the outer ring cavity is collinear with the centerline of the piston, and the centerline of the inner ring cavity is collinear with the centerline of the eccentric combustion chamber.

2. The eccentric inner-cooling oil chamber piston according to claim 1, characterized in that: The wall thicknesses L2 and L3 from the circumference of the inner ring cavity to the combustion chamber remain consistent, and the wall thicknesses L6 and L7 from the outer wall of the outer ring cavity to the piston ring groove remain consistent.

3. The eccentric inner-cooling oil chamber piston according to claim 1, characterized in that: The annular upper wall of the inner cooling oil chamber is formed by a plane wall and curved walls on both sides of the plane wall. The widths of the plane walls on both sides of the axis of the inner cooling oil chamber are L8 and L9 respectively, where: L8>L9>0, and (L8-L9) / 2=L1.

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