Piston structure of internal combustion engine

Abstract

The invention relates to the technical field of internal combustion engine pistons, and provides an internal combustion engine piston structure which comprises a piston, the piston is provided with an annular groove used for installing gas rings or oil rings, the piston is sequentially sleeved with at least two gas rings and at least one oil ring from top to bottom, and the gas ring at the uppermost end is a totally-closed piston ring. A backpressure hole is formed in a ring groove between the uppermost gas ring and the uppermost oil ring of the piston, the backpressure hole is used for communicating the outer side of the piston with a connecting rod cavity on the inner side of the piston, the uppermost totally-closed gas ring is arranged, and the backpressure hole for communicating the outer side of the piston with the connecting rod cavity is formed in the ring groove between the uppermost gas ring and the uppermost oil ring. The initial sealing performance of the piston and the cylinder wall is improved, engine oil backflow is achieved to reduce the problems of oil pumping and engine oil burning, and meanwhile high-pressure back pressure in the acting stroke is rapidly released.

Description

TECHNICAL FIELD

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

[0002] In an internal combustion engine, the piston is the core component of mechanical movement, and the cooperation effect of the ring groove and the piston ring directly determines the sealing performance of the combustion chamber of the internal combustion engine. Among them, the core function of the gas ring is to block the high-temperature and high-pressure gas in the combustion chamber from leaking to the crankcase, and the oil ring is responsible for scraping the excess oil on the surface of the cylinder wall.

[0003] In the prior art, in order to improve the sealing effect, multiple gas rings are often used in the internal combustion engine piston, among which the double-gas-ring layout is widely used. However, in the actual operation process, the double-gas-ring structure has multiple design defects, which leads to insufficient sealing performance and use reliability: firstly, the double-gas-ring only relies on the opening staggered angle to achieve sealing, and no effective circumferential positioning mechanism is provided. When the piston reciprocates, the gas ring is easily affected by factors such as inertial impact and gas pressure fluctuation to slide circumferentially, which causes the preset opening staggered angle to deviate or even align, forming a straight-through leakage path for the gas, and seriously damaging the sealing effect; secondly, the oil ring does not scrape the oil, which will flow upward, not only causing waste of oil, but also accumulating in the ring groove and carbonizing at high temperature to form carbon deposits. The carbon deposits will fill the gap between the ring grooves, hinder the circumferential and axial movement of the gas ring, reduce the gas flow space, and make the gas that leaks between the gas rings unable to be quickly discharged, resulting in a continuous rise in back pressure. The increased back pressure will push the first gas ring upward, causing it to float away from the piston ring groove. The piston ring floats obliquely, causing the piston ring to vibrate and partially separate from the cylinder wall, which greatly reduces the sealing performance, further increases the amount of gas leakage, and more gas leaks into the ring groove to further increase the back pressure, forming a vicious cycle of carbon deposit accumulation, back pressure increase, first ring floating, gas leakage aggravation, and higher back pressure, which eventually leads to the complete loss of sealing function of the first gas ring; thirdly, the existing structure lacks precise matching optimization of the back gap size, and the too small back gap becomes a key hidden danger triggering oil burning and secondary faults. As a reserved space for the piston ring and the bottom of the ring groove, a too small back gap will cause the piston ring to have no expansion allowance after being heated and expanded, and will not be able to tightly adhere to the cylinder wall through its own elasticity, which not only weakens the sealing ability of the gas ring, but also reduces the scraping force of the oil ring. At the same time, the oil scraped by the oil ring has no temporary storage space and is easy to accumulate in the ring groove and flow upward to the combustion chamber, and the gas that leaks into the ring groove will impact the oil and accelerate its atomization and inhalation, directly causing oil burning and possibly causing piston ring jamming, cylinder wall damage, and other secondary faults, further aggravating the sealing failure; fourthly, the space between the gas rings is easy to accumulate high-pressure back pressure that is not discharged in time. This back pressure will push the gas ring to deviate axially along the ring groove in the opposite direction, aggravating the friction and wear between the gas ring and the piston ring groove, shortening the service life, and interacting with the problems of carbon deposit accumulation, too small back gap, and opening misalignment failure to continuously enlarge the defects of the existing structure. SUMMARY

[0004] The present application aims to provide an internal combustion engine piston structure, which solves the problems of easy oil channeling into the combustion chamber, high back pressure between the gas ring and the oil ring, and unstable sealing in the prior art.

[0005] The present application is implemented by the following technical scheme: an internal combustion engine piston structure, comprising a piston, the piston being provided with a ring groove for mounting a gas ring or an oil ring, the outer side of the piston being sequentially sleeved with at least two gas rings and at least one oil ring from top to bottom, the uppermost gas ring being a fully-closed piston ring, and the piston being provided with a back pressure hole in the ring groove between the uppermost gas ring and the uppermost oil ring, the back pressure hole being used for connecting the outer side of the piston and the connecting rod cavity on the inner side of the piston.

[0006] Further, the uppermost gas ring is composed of two open rings arranged in a staggered manner, the two open rings being mutually clamped and matched and / or being respectively clamped and matched with the piston.

[0007] Further, the two open rings are staggered by an angle of 3°-90° in the circumferential direction of the piston.

[0008] Further, the opening width of the upper open ring is smaller than that of the lower open ring.

[0009] Further, one of the open rings is provided with a first boss, and the other open ring is provided with a first groove for positioning and clamping the first boss.

[0010] Further, one of the open rings is provided with a second boss for positioning and clamping the opening of the other open ring.

[0011] Further, the open ring is provided with a third boss in the radial and / or axial direction, and the piston is provided with a third groove for positioning and clamping the third boss.

[0012] Further, the open ring is provided with a fourth groove, and the piston is provided with a fourth boss for positioning and clamping the fourth groove.

[0013] Further, the uppermost gas ring is made of at least two continuous and close windings of ring pieces.

[0014] Further, the uppermost gas ring comprises two ring bodies, and at least one of the ring bodies is a snap type sealing ring.

[0015] The present application has at least the following advantages and beneficial effects: (1) By arranging the uppermost fully-closed gas ring and the back pressure hole in the ring groove between the uppermost gas ring and the uppermost oil ring for connecting the outer side of the piston and the connecting rod cavity, the initial sealing performance of the piston and the cylinder wall is improved, the oil backflow is realized to reduce the oil channeling and the oil burning, and the high pressure back pressure in the working stroke is quickly released.

[0016] (2) By setting the uppermost gas ring as two open rings with staggered openings and mutual clamping / opening rings respectively clamped with the piston, a double sealing barrier is formed to avoid direct gas passage, improve sealing reliability and exhaust pressure efficiency, balance exhaust pressure and sealing performance, enhance sealing stability and prolong the service life of the gas ring. BRIEF DESCRIPTION OF DRAWINGS

[0017] Figure 1 A structural schematic diagram of an internal combustion engine piston structure is provided.

[0018] Figure 2 A partial sectional view of an internal combustion engine piston structure during the suction stroke is provided.

[0019] Figure 3 A partial sectional view of an internal combustion engine piston structure during the working stroke is provided.

[0020] Figure 4 A structural schematic diagram of two open rings in Example Three of the present application is provided.

[0021] Figure 5 A structural schematic diagram of two open rings in Example Four of the present application is provided.

[0022] Figure 6 A structural schematic diagram of two open rings with an axially arranged third boss in Example Five of the present application is provided.

[0023] Figure 7 A structural schematic diagram of two open rings with a radially arranged third boss in Example Five of the present application is provided.

[0024] Figure 8 A structural schematic diagram of two open rings in Example Six of the present application is provided.

[0025] Figure 9 A structural schematic diagram of the uppermost gas ring in Example Seven of the present application is provided.

[0026] Figure 10 A structural schematic diagram of the ring body in Example Eight of the present application is provided.

[0027] Figure 11 Another structural schematic diagram of the ring body in Example Eight of the present application is provided.

[0028] Reference signs: 1-piston, 10-back pressure hole, 11-ring groove, 2-gas ring, 20-open ring, 211-first boss, 212-first recess, 22-second boss, 23-third boss, 24-fourth recess, 3-oil ring. DETAILED DESCRIPTION

[0029] The specific embodiments are described below in conjunction with the accompanying drawings.

[0030] Example One like Figures 1 to 3 As shown, this embodiment mainly discloses an internal combustion engine piston structure, including a piston 1. The piston 1 has an annular groove 11 for installing a compression ring 2 or an oil ring 3. At least two compression rings 2 and at least one oil ring 3 are sequentially sleeved on the outside of the piston 1 from top to bottom. The uppermost compression ring 2 is a fully enclosed piston ring. The piston 1 has a back pressure hole 10 in the annular groove 11 between the uppermost compression ring 2 and the uppermost oil ring 3. The back pressure hole 10 is used to connect the outer side of the piston 1 with the inner connecting rod cavity of the piston 1.

[0031] Specifically, In terms of sealing performance, the uppermost piston ring 2 is a fully enclosed piston ring, which blocks gas leakage and improves the initial sealing performance between piston 1 and cylinder wall; in terms of oil return and back pressure reduction, the space between the uppermost piston ring 2 and the uppermost oil ring 3 on the outside of piston 1 is connected to the connecting rod cavity inside piston 1 through the back pressure hole 10.

[0032] It should be noted that there is a side clearance between the upper and lower planes of the compression ring 2 and the ring groove 11, and a back clearance between the compression ring 2 and the bottom of the ring groove 11. During the intake stroke, the piston 1 moves from top to bottom in the cylinder. At this time, the compression ring 2 abuts against the upper plane of the ring groove 11 under the action of the piston 1. During the movement of the piston 1, the oil leaked by the oil ring 3 enters the back clearance from the lower side clearance between the compression ring 2 and the piston 1 through the scraping of the compression ring 2, and then flows back to the connecting rod chamber through the back pressure hole 10. This prevents the oil from accumulating in the area from the back pressure hole 10 to the uppermost oil ring 3, reducing the problems of oil leakage and oil burning. During the power stroke, piston 1 moves from top to bottom in the cylinder. At this time, the compression ring 2 comes into contact with the lower plane in the ring groove 11 under the action of fuel combustion. The gas expanding in the combustion chamber may flow downward through the gap between the inner wall of the cylinder and the uppermost compression ring 2. High-pressure gas accumulates in the area from the back pressure hole 10 to the uppermost compression ring 2. It enters the back clearance from the upper side gap between the compression ring 2 and piston 1, and then is discharged to the connecting rod chamber through the back pressure hole 10, quickly releasing the high pressure back pressure.

[0033] Example 2 like Figures 1 to 3 As shown, in this embodiment, the main structure is completely the same as in Embodiment 1. The difference lies in that the uppermost gas ring 2 is composed of two staggered open rings 20. The two open rings 20 are interlocked and / or each of the two open rings 20 is interlocked with the piston 1. The use of two stacked open rings 20 forms a double sealing barrier. At the same time, the staggered arrangement of the open rings 20 avoids the formation of a straight gas passage when the two openings are aligned, thus improving the reliability of the seal.

[0034] Furthermore, in specific implementations, the angle at which the two open rings 20 provided in this embodiment of the invention are staggered from each other along the circumference of the piston 1 is 3° to 90°. Specifically, by shortening the circumferential distance between the openings of the two open rings 20, gas can be discharged quickly through a shorter path, significantly improving the pressure relief efficiency and avoiding back pressure accumulation that could cause the two open rings 20 to separate; a balance is achieved between "rapid pressure relief" and "effective sealing," improving sealing stability and the service life of the gas ring 2.

[0035] Furthermore, in specific implementation, the opening width of the upper opening ring 20 provided in the embodiment of the present invention is smaller than the opening width of the lower opening ring 20. This allows the lower opening ring 20 to more easily introduce gas into the back gap to form a larger upward pressure, creating a pressure difference with the smaller upward pressure of the upper ring. This firmly presses the two opening rings 20 into the ring groove 11, preventing the ring from floating, ensuring sealing stability, reducing impact wear between the ring and the ring groove 11, and extending the service life of the uppermost gas ring 2.

[0036] Furthermore, in specific implementations, the back pressure holes 10 provided in the embodiments of the present invention are provided with one or several evenly spaced along the circumference of the piston 1. By adjusting the diameter of the back pressure holes 10 and the number of circumferentially arranged holes, the back pressure intensity in the piston ring area can be flexibly adjusted to ensure that the upper open ring 20 is always subjected to stable pressure and fits against the ring groove 11, effectively preventing it from floating due to back pressure fluctuations. At the same time, the parameter optimization of the back pressure holes 10 can also synchronously adjust the oil return rate. When the hole diameter is enlarged or the density is increased, the oil return efficiency is improved, which can further reduce the accumulation of oil in the ring groove 11. Conversely, it can precisely control the oil return amount according to the operating conditions of the internal combustion engine, adapting to the usage requirements under different scenarios. In addition, the opening of the back pressure holes 10 should avoid damaging the overall rigidity of the piston 1.

[0037] Example 3 like Figure 4 As shown, in this embodiment, the main structure is completely the same as in Embodiment 2. The difference lies in that one of the open rings 20 is provided with a first boss 211, and the other open ring 20 is provided with a first groove 212 that engages with the first boss 211. After the first boss 211 and the first groove 212 are engaged, the circumferential relative movement of the two open rings 20 is restricted. During the reciprocating motion of the piston 1, neither of the two open rings 20 can rotate relative to the other, ensuring that the opening misalignment angle remains stable and eliminating the potential for sliding and deviating of the opening from a structural perspective. At the same time, the cooperation between the first boss 211 and the first groove 212 has a guiding and positioning function. During assembly, no manual measurement and adjustment are required. Simply align the first boss 211 with the first groove 212 and insert it to complete the angle alignment, greatly improving assembly efficiency and reducing assembly errors.

[0038] Example 4 likeFigure 5 As shown, in this embodiment, the main structure is completely the same as in Embodiment 2. The difference is that one of the open rings 20 is provided with a second protrusion 22 that engages with the opening of the other open ring 20. Specifically, the second protrusion 22 of one open ring 20 is fitted into the opening of the other open ring 20, restricting the circumferential relative movement of the two open rings 20.

[0039] Example 5 like Figure 6 and Figure 7 As shown, in this embodiment, the main structure is completely the same as in Embodiment 2. The difference is that a third boss 23 is provided on the open ring 20 along the radial and / or axial direction, and the piston 1 has a third groove that is positioned and engaged with the third boss 23. By cooperating with the third groove, the relative position of the two open rings 20 and the piston 1 is limited, preventing the two open rings 20 from moving around in the circumferential and axial directions.

[0040] Example 6 like Figure 8 As shown, in this embodiment, the main structure is completely the same as in Embodiment 2. The difference is that a fourth groove 24 is provided on the open ring 20, and a fourth boss is provided on the piston 1 to be positioned and engaged with the fourth groove 24. By cooperating with the fourth groove 24, the relative positions of the two open rings 20 and the piston 1 are limited, preventing the two open rings 20 from moving around in the circumference and axial direction.

[0041] Example 7 like Figure 9 As shown, in this embodiment, the main structure is completely the same as in Embodiment 2. The difference is that the uppermost gas ring 2 is made by continuously and tightly winding at least two turns of ring plate without obvious gaps. This structurally blocks the direct path of gas flow, resulting in strong sealing continuity and a tighter fit to the cylinder wall. This not only improves the initial sealing performance but also simplifies the structure and reduces the risk of leakage.

[0042] Example 8 like Figure 10 and Figure 11 As shown, in this embodiment, the main structure is completely the same as in Embodiment 2. The difference is that the uppermost air ring 2 includes two ring bodies, and at least one of the ring bodies is a snap-on sealing ring. The structure of two ring bodies with at least one snap-on sealing ring ensures the reliability of single-ring sealing, and the double protection avoids opening alignment failure. At the same time, it can cooperate with the back pressure hole 10 to quickly release pressure, taking into account both sealing effect and pressure release efficiency, and the assembly is also more flexible.

Claims

1. An internal combustion engine piston structure comprising a piston (1) provided with a ring groove (11) for mounting a gas ring (2) or an oil ring (3), characterized in that, The piston (1) is sequentially sleeved with at least two air rings (2) and at least one oil ring (3) from top to bottom, the uppermost air ring (2) is a full-closed piston ring, a back pressure hole (10) is arranged in the ring groove (11) between the uppermost air ring (2) and the uppermost oil ring (3) of the piston (1), and the back pressure hole (10) is used for connecting the outer side of the piston (1) and the inner side connecting rod cavity of the piston (1).

2. A piston structure for an internal combustion engine according to claim 1, wherein The uppermost air ring (2) is composed of two open rings (20) arranged in an open position error mode, the two open rings (20) are clamped and matched with each other and / or the two open rings (20) are respectively clamped and matched with the piston (1).

3. A piston structure for an internal combustion engine according to claim 2, wherein The angle of mutual staggering of the two open rings (20) along the circumference of the piston (1) is 3°-90°.

4. A piston structure for an internal combustion engine according to claim 2, wherein The opening width of the upper open ring (20) is smaller than that of the lower open ring (20).

5. A piston structure for an internal combustion engine according to claim 2, wherein One of the open rings (20) is provided with a first boss (211), and the other open ring (20) is provided with a first groove (212) for positioning and clamping the first boss (211).

6. A piston structure for an internal combustion engine according to claim 2, wherein One of the open rings (20) is provided with a second boss (22) for positioning and clamping the opening of the other open ring (20).

7. A piston structure for an internal combustion engine according to claim 2, 5 or 6, characterized in that The open ring (20) is provided with a third boss (23) in the radial and / or axial direction, and the piston (1) is provided with a third groove (213) for positioning and clamping the third boss (23).

8. A piston structure for an internal combustion engine according to claim 2, 5 or 6, characterized by The open ring (20) is provided with a fourth groove (24), and the piston (1) is provided with a fourth boss (214) for positioning and clamping the fourth groove (24).

9. A piston structure for an internal combustion engine according to claim 1, wherein The uppermost air ring (2) is made of at least two continuous and close windings of ring pieces.

10. A piston structure for an internal combustion engine according to claim 1, wherein The uppermost air ring (2) includes two ring bodies, and at least one of the ring bodies is a buckle type sealing ring.

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