An engine piston with a high-efficiency oil return and weight reduction structure
By designing a pipe-shaped weight-reduction groove and a through-face window below the fourth ring land of the piston, the problems of poor oil return and weight reduction are solved, achieving efficient oil return and weight reduction, and improving engine performance and life.
Patent Information
- Application Number
- CN202522314639.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-31
- Publication Date
- 2026-11-06
- Estimated Expiration
- 2035-10-31
AI Technical Summary
Existing engine pistons suffer from poor oil return during high-speed operation, leading to high oil consumption, increased carbon buildup, and increased emissions. At the same time, it is difficult to balance lightweight design with structural strength, affecting engine performance and lifespan.
A concave, pipe-shaped weight-reduction groove and a through-face window are designed below the fourth ring land of the piston to form a dual oil return path. Combined with a smooth flow-guiding surface, the oil is guided back and the weight is precisely reduced in the non-load-bearing area.
It significantly improves oil return efficiency, reduces oil consumption and carbon deposits, enhances engine performance and fuel economy, improves NVH performance, and ensures structural reliability and weight reduction.
Smart Images
Figure CN224943806U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of internal combustion engine piston technology, and in particular to an engine piston with a high-efficiency oil return and weight reduction structure. Background Technology
[0002] The piston is the "heart" of the engine. It performs reciprocating motion in harsh environments with high temperature, high pressure and high mechanical stress. The quality of its structural design directly determines the engine's power, fuel economy, reliability and emission levels.
[0003] In high-speed engines, the fourth annular land region, located below the oil ring groove at the bottom of the piston, faces two long-standing and interconnected technical bottlenecks in its design: First, there's the problem of poor oil return. When the engine is running, the oil ring scrapes excess oil off the cylinder walls. This scraped oil needs to return smoothly to the crankcase through the return holes or gaps on the fourth ring land. Traditional pistons often have a solid structure below the fourth ring land, or a limited number of return holes with winding paths. This results in insufficient oil return rate at high speeds. Oil that isn't promptly removed accumulates in the fourth ring land area and, under the piston's "pumping effect," is carried into the combustion chamber by the rising combustion gases. This not only increases oil consumption but also causes a series of problems such as combustion chamber carbon buildup, spark plug contamination, and increased emissions, severely damaging engine performance and lifespan.
[0004] Second, there is a conflict between lightweighting and structural strength. As the main reciprocating mass, the weight of the piston directly affects the engine's inertial force, vibration and noise (NVH), and responsiveness. The current mainstream weight reduction method is to hollow out the inner side of the piston skirt to create a weight reduction cavity. However, this weight reduction method often lacks specificity. Blindly removing material can weaken the support stiffness of key stress areas such as the piston pin and piston rings, causing excessive deformation of the piston under the impact of combustion, affecting the sealing effect of the piston rings and piston rings, and even causing abnormal wear or scoring of the piston skirt.
[0005] Therefore, there is an urgent need in this field for an innovative piston structure that can achieve "precise weight reduction" while ensuring the structural strength of key components, and effectively improve the oil return efficiency in the fourth ring area, thereby comprehensively improving the overall performance of the engine. Utility Model Content
[0006] This invention addresses the aforementioned problems in the existing technology by providing an engine piston with a high-efficiency oil return and weight reduction structure.
[0007] The objective of this utility model is mainly achieved through the following solution: An engine piston with a high-efficiency oil return and weight reduction structure includes a piston top, a piston head, and a piston skirt. The piston head is provided with several annular grooves. The space between adjacent annular grooves and the lower side of the lowermost annular groove are annular lands. The lower side of the lowermost annular land is provided with an inwardly recessed weight reduction groove facing the center of the piston interior. One or more through windows are provided in the internal area of the weight reduction groove.
[0008] Preferably, the contour of the weight-reducing groove adopts a smooth curve to form a drainage surface that guides the oil from the side wall of the piston skirt to the center of the piston.
[0009] Preferably, the shape of the face window is circular, elliptical, or oblong.
[0010] Preferably, the pipe-shaped weight-reducing groove and the face window are arranged symmetrically with respect to the piston pin hole axis.
[0011] In summary, compared with the prior art, the present invention has the following beneficial technical effects: (1) This utility model has efficient oil return and significantly reduces oil consumption. The flow-guiding curved surface of the weight reduction groove provides a wide and smooth flow channel for the oil scraped from the oil ring, which can guide the oil to flow quickly into the piston, greatly reducing the oil retention and accumulation in the fourth ring land area. At the same time, the through-hole provides an additional and more direct oil return channel, forming a dual oil return path, which doubles the oil return efficiency, thereby fundamentally and effectively preventing abnormal oil surge, reducing oil consumption, and reducing carbon deposits and emissions pollution. (2) This utility model achieves precise weight reduction and improves engine performance. The weight reduction structure is concentrated in the non-major load-bearing area below the fourth ring. Through the design of the weight reduction groove and the face window, precise weight reduction is achieved. It avoids the negative impact of blind weight reduction on the rigidity of the piston head and the support strength of the pin seat. The reduced reciprocating mass is directly converted into a lower reciprocating inertial force, which helps to improve the engine's maximum speed, power density and acceleration response, while improving fuel economy and NVH performance. (3) The smooth flow-guiding curved surface transition of the weight reduction groove in this utility model avoids stress concentration and ensures that the area still has sufficient structural reliability after thinning, which is conducive to the long-term stable operation of the piston assembly. Attached Figure Description
[0012] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is the front view of this utility model; Figure 3 This is a side view of the present invention; Figure 4 This is a schematic diagram of another type of face window in this utility model.
[0013] Reference numerals: 1-Piston top; 2-Piston head; 3-Piston skirt; 4-Annular groove; 5-Annular land; 6-Weight reduction groove; 7-Face window; 8-Smooth curve; 9-Drainage surface; 10-Piston pin hole. Detailed Implementation
[0014] The technical solution of this utility model will be further described in detail below through specific embodiments and in conjunction with the accompanying drawings. It should be understood that the implementation of this utility model is not limited to the following embodiments, and any modifications and / or alterations made to this utility model will fall within the protection scope of this utility model.
[0015] like Figure 1 , 2 As shown in Figures 1 and 3, this utility model discloses a technical solution: an engine piston with a high-efficiency oil return and weight reduction structure, including a piston top 1, a piston head 2, and a piston skirt 3.
[0016] The outer wall of the piston head 2 is provided with several annular grooves 4, preferably three, of which the upper two are gas ring grooves and the lower one is an oil ring groove; the space between adjacent annular grooves 4 and the lower part of the bottom annular groove 4 are annular lands 5, of which the bottommost annular land is the fourth annular land 5, which is the core area for oil return.
[0017] On the lower side of the fourth ring bank 5, a concave pipe-shaped weight reduction groove 6 is provided along the radial direction of the piston toward the center of the piston interior. The outline of the pipe-shaped weight reduction groove 6 is composed of a continuous smooth curve 8, forming a drainage surface 9 that gently transitions from the side wall of the piston skirt 3 to the center of the piston. The design of the pipe-shaped weight reduction groove 6 removes redundant material while avoiding weakening the root thickness of the fourth ring bank 5.
[0018] The internal area of the pipe-shaped weight-reducing groove 6 has one or more through windows 7. In this embodiment, two windows 7 are provided on each side. Of course, the number of windows 7 can be increased or decreased according to actual process and performance requirements. The shape of the windows 7 can be circular, elliptical, or oblong. Figure 1 , 4 As shown, the face window 7 can be set horizontally or gradually tilted downwards toward the center of the piston.
[0019] Specifically, the pipe-shaped weight-reducing groove 6 and the two side windows 7 are symmetrically arranged with respect to the axis of the piston pin hole 10, with a symmetry error of ≤0.1mm, to ensure uniform mass distribution during piston reciprocating motion and avoid additional inertial forces and vibrations caused by eccentricity.
[0020] The working principle of this invention is as follows: When the engine is running, the oil ring scrapes off excess oil from the cylinder wall. Part of the scraped oil flows down the cylinder wall, while the other part enters the fourth ring land area 5. At this time, the structure of this invention begins to function: most of the oil is effectively captured and guided by the guiding surface 9 of the pipe-shaped weight reduction groove 6 under the action of piston downward movement and gravity, and flows rapidly towards the central area inside the piston along the smooth surface. At the same time, some oil falls directly through the through-hole window 7. This dual oil return path greatly improves the oil return efficiency and avoids oil accumulation. In addition, the pipe-shaped weight reduction groove 6 and the window 7 remove redundant mass in the non-core load-bearing area below the fourth ring land, achieving effective weight reduction.
[0021] The piston of this invention can be integrally formed by casting or forging, and the pipe-shaped weight-reducing groove 6 and face window 7 on it can be precisely obtained by machining.
[0022] The following is a test of the pistons in a 1.5L gasoline engine: The specific parameters are as follows: The piston top 1 has a flat top structure with a diameter of 82mm; the piston head 2 has 3 ring grooves 4, with the gas ring groove being 3mm wide and the oil ring groove being 5mm wide; the root thickness of the fourth ring land 5 is 16mm; a pipe-shaped weight reduction groove 6 is provided on the lower side of the fourth ring land 5, and two oblong windows 7 are opened on the corresponding areas on both sides of the weight reduction groove 6 relative to the piston pin hole.
[0023] Operating results: At 4000rpm, the oil ring scraping rate is 90mL / min, the oil return rate can reach 88mL / min, and the oil return efficiency is 97.8%; the piston weight is reduced from 360g to 330g, a weight reduction of 8.3%; the reciprocating inertial force is reduced from 45N to 40N; in the whole engine NVH test, the vibration acceleration in the 1000-4000rpm frequency band is reduced by 15%; after 1000 hours of continuous operation, the carbon deposit thickness in the combustion chamber is only 0.1mm, and the oil consumption is stable at 0.14L / 1000km.
[0024] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.
Claims
1. An engine piston with a high-efficiency oil return and weight reduction structure, comprising a piston top (1), a piston head (2), and a piston skirt (3), characterized in that: The piston head (2) is provided with several annular grooves (4); the area between adjacent annular grooves (4) and the lower part of the bottom annular groove (4) are all annular lands (5), wherein the lower side of the bottom annular lands (5) is provided with an inwardly recessed weight reduction groove (6) facing the center of the piston interior; one or more through windows (7) are provided in the internal area of the weight reduction groove (6).
2. An engine piston with a high-efficiency oil return and weight reduction structure according to claim 1, characterized in that: The contour of the weight reduction groove (6) adopts a smooth curve (8) to form a drainage surface (9) that guides the oil from the side wall of the piston skirt (3) to the center of the piston.
3. An engine piston with a high-efficiency oil return and weight reduction structure according to claim 1, characterized in that: The shape of the face window (7) is circular, elliptical or oblong.
4. An engine piston with a high-efficiency oil return and weight reduction structure according to claim 1, characterized in that: The pipe-shaped weight-reducing groove (6) and the face window (7) are arranged symmetrically with respect to the piston pin hole (10) axis.