WO2023174003A1

WO2023174003A1 - Piston and engine

Info

Publication number: WO2023174003A1
Application number: PCT/CN2023/077047
Authority: WO
Inventors: 窦站成; 崔京朋; 梁伟; 刘近报; 李志杰; 王德成
Original assignee: 潍柴动力股份有限公司
Priority date: 2022-03-17
Filing date: 2023-02-16
Publication date: 2023-09-21
Also published as: CN114352431A; CN114352431B

Abstract

A piston and an engine. The piston comprises a piston body (1), the top of which is provided with a combustion chamber (2). The combustion chamber comprises a first ring groove (21), a second ring groove (22) and a third ring groove (23) sequentially arranged in a direction from the bottom of the piston body to the top of the piston body and having sequentially increasing diameters; the bottom of the combustion chamber is provided with a protruding part (3); the first ring groove, the second ring groove and the third ring groove are coaxial and communicated with each other, and are all arranged around the protruding part; the second ring groove comprises an annular outer side wall (221) and a bottom wall (222) located on the inner side of the outer side wall and connected to the outer side wall, and a boss (24) is formed between the bottom wall and the first ring groove; the third ring groove comprises an arc-shaped concave part (231), the inner end of the arc-shaped concave part is connected to the end of the outer side wall distant from the bottom wall, and the outer end of the arc-shaped concave part is connected to the top surface of the piston body.

Description

Pistons and engines

This application claims the priority of the invention patent filed with the China Patent Office on March 17, 2022, with the application number 202210260961.0 and the invention title "A piston and an engine", the entire content of which is incorporated into this application by reference.

Technical field

This application relates to the field of engine technology, for example, to a piston and an engine.

Background technique

The engine is an important part of power devices such as vehicles, and the combustion chamber is one of the core components of the engine. The structure of the combustion chamber plays an important role in the thermal efficiency of the engine and the fuel economy of the engine.

In recent years, as people's awareness of environmental protection has increased, various car companies have paid more and more attention to the thermal efficiency of the engine and the fuel economy of the engine. However, related technologies are limited by the structure of the combustion chamber, the thermal efficiency of the engine and the fuel economy of the engine. The economics are not ideal yet.

Therefore, there is an urgent need to design a new combustion chamber structure to improve the above problems.

Contents of the invention

The present application provides a piston and an engine that can improve the problem of unsatisfactory thermal efficiency of the engine and unsatisfactory fuel economy of the engine due to the structure of the combustion chamber.

One embodiment provides a piston, including:

The piston body is provided with a combustion chamber at the top of the piston body, and a convex portion is provided at the bottom of the combustion chamber; the combustion chambers are arranged sequentially in a direction from the bottom of the piston body to the top of the piston body. The first annular groove, the second annular groove and the third annular groove, the diameters of the first annular groove, the second annular groove and the third annular groove increase in sequence, the first annular groove, the The second annular groove and the third annular groove are coaxial and connected with each other, and the first annular groove, the second annular groove and the third annular groove are all arranged around the protrusion;

Wherein, the second annular groove includes an annular outer wall and is located inside the outer wall and connected with The bottom wall is connected to the outer side wall, and a boss extending in the direction of the axis of the piston body is formed between the bottom wall and the first annular groove;

The third annular groove includes an arc-shaped concave portion, the inner end of the arc-shaped concave portion is connected to an end of the outer wall away from the bottom wall, and the outer end of the arc-shaped concave portion is connected to an end of the piston body. The top surface is connected; during engine operation, the arc-shaped concave surface can form an air interlayer between the mixture and the air mixture.

The piston provided by this application includes a piston body with a combustion chamber on the top, and a convex portion is provided on the bottom of the combustion chamber. The combustion chamber includes a third piston body with a caliber that is sequentially arranged in a direction from the bottom of the piston body to the top of the piston body and whose caliber increases sequentially. The first annular groove, the second annular groove and the third annular groove are coaxial and connected with each other, and are all arranged around the protrusion. The second annular groove includes an annular outer wall and a bottom wall located inside the outer wall and connected to the outer wall. A boss extending in the direction of the axis of the piston body is formed between the bottom wall and the first annular groove. With the help of the kinetic energy of the fuel itself and the second annular groove, the fuel injected onto the combustion chamber wall can be effectively guided, and then the fuel beam is directed to the space of the third annular groove. The third ring groove includes an arc-shaped concave portion. The inner end of the arc-shaped concave portion is connected to an end of the outer wall of the second ring groove away from the bottom wall of the second ring groove. The outer end of the arc-shaped concave portion is connected to the top surface of the piston body. connect. During the operation of the piston, when it reaches a predetermined position (for example, when the piston moves to near the top dead center of the engine), a strong squeezing flow will be formed from the outer edge to the center of the combustion chamber. The fuel flows to the center of the combustion chamber, and finally forms a relatively uniform mixture in the upper space of the second and third annular grooves. The turbulence in the combustion chamber is fully utilized to form a mixture in the upper space of the second and third annular grooves. Combustion enables the piston provided by this application to make full use of the combustion chamber space and form a uniform mixture inside the entire combustion chamber. Making full use of the combustion chamber space for mixing and combustion can fully increase the heat release rate of the entire combustion process, especially the heat release rate when the crankshaft angle is 8° to 30°, thereby improving engine thermal efficiency and engine fuel economy.

During engine operation, under the interaction of the strong squeeze flow at the edge of the piston and the oil jet, an air interlayer is formed between the arc-shaped concave portion of the third ring groove and the mixture. The air interlayer can reduce heat loss and effectively reduce the piston's wear and tear. Reduce heat transfer loss, improve thermal efficiency, and further reduce engine fuel consumption.

In addition, the piston provided by this application makes full use of the space of the entire combustion chamber to form a uniform mixture. In this way, the fuel-rich area is reduced during the combustion process, and the high-temperature combustion area inside the combustion chamber is reduced. Therefore, nitrogen can be significantly reduced. Formation of oxygen compounds while fuel mixes with space Sufficient can significantly reduce the formation of particulate matter.

Optionally, the diameter of the portion of the boss closest to the axis of the piston body is 50% to 55% of the outer diameter of the piston body.

Optionally, the boss is an arcuate boss. Along the axis direction of the piston body, in the longitudinal section of the piston body, the center of the circle where the arc surface of the arcuate boss is located coincides with the third The distance between the lowest parts of an annular groove is H1, and H1 is 7% to 8% of the outer diameter of the piston body.

Optionally, the third annular groove includes a planar portion and an arc-shaped convex portion, the inner end of the planar portion is connected to the second annular groove, and the outer end of the planar portion is connected to the arc-shaped concave portion. The inner end is connected; the inner end of the arc-shaped convex portion is connected to the outer end of the arc-shaped concave portion, and the outer end of the arc-shaped convex portion is connected to the top surface of the piston body.

Optionally, the outer wall of the second annular groove is perpendicular to the top surface of the piston body;

In the radial direction of the piston body, the distance between the outer end of the flat part and the outer wall of the second ring groove is W3, and the outer end of the arc-shaped convex part and the second ring groove The distance between the outer side walls of the groove is W4, and the value of W4/W3 is 3 to 4.

Optionally, at least one of the following solutions is also included:

The radius of the arc-shaped concave portion is 2 to 3 times the radius of the arc-shaped convex portion;

The depth of the third annular groove is 2.5% to 4.5% of the thickness of the piston body;

The diameter of the third annular groove is 80% to 90% of the outer diameter of the piston body.

Optionally, at least one of the following solutions is also included:

The part with the smallest inner diameter of the arc boss is the throat. On the same radius of the piston body, the part of the first annular groove farthest from the axis of the piston body is between the corresponding part of the throat. The distance is d. When the outer diameter of the piston body is less than or equal to 150 mm, d is 0.5% to 1% of the outer diameter of the piston body;

In the longitudinal section of the piston body, the distance between the center of the circle where the arc surface of the arc surface boss is located and the lowest part of the first annular groove in the axial direction of the piston body is 9 to 10 times d. times.

Optionally, at least one of the following solutions is also included:

On the same radius of the piston body, the distance between the part of the boss closest to the axis of the piston body and the outer wall is 4% to 5% of the outer diameter of the piston body;

The outer side wall of the second ring groove is connected to the third ring groove through a first fillet, and the outer wall of the second ring groove is connected to the third ring groove through a first fillet. The fillet is connected to the bottom wall; the distance between the flat part and the center of the second fillet in the axial direction of the piston body is 1.1% to 1.3% of the outer diameter of the piston body;

The caliber at the outer wall of the second annular groove is 55% to 65% of the outer diameter of the piston body;

The bottom wall of the second annular groove includes a tapered surface, and an included angle between the tapered surface and the top surface of the piston body is 8° to 25°.

Optionally, the distance between the lowest part of the first annular groove and the top surface of the piston body is 13% to 20% of the outer diameter of the piston body.

Optionally, the first annular groove includes a first arc segment and a second arc segment that are smoothly connected, the first arc segment is located at the bottom of the first annular groove, and the second arc segment Connect the first arc segment and the second annular groove;

The circle where the first arc segment is located is the first circle, the circle where the second arc segment is located is the second circle, and the second circle is located in the first circle and is connected with the first circle. The circles are tangent, and the center of the first circle is closer to the axis of the piston body than the center of the second circle; the part of the first circle closest to the axis of the piston body is in contact with the second circle. The distance between the parts farthest from the axis of the piston body is W1, and the value of W1/H1 is 1.65-1.9.

Optionally, the raised portion includes a truncated cone portion disposed at the bottom of the combustion chamber and located in the combustion chamber, and a spherical portion disposed on a side of the truncated cone portion facing the top surface of the piston body, wherein, The cone angle of the truncated cone portion is 92° to 96°, and the radius of the spherical portion is 15 to 20 mm.

This application also provides an engine, including any piston provided in the above technical solutions.

The engine provided by this application can reduce heat loss, effectively reduce the heat transfer loss of the piston, improve thermal efficiency, and reduce engine fuel consumption. At the same time, the piston makes full use of the entire combustion chamber space to form a uniform mixture. This reduces the excessively rich fuel area during the combustion process and reduces the high-temperature combustion area inside the combustion chamber. Therefore, the formation of nitrogen oxide compounds can be significantly reduced. , and at the same time, sufficient mixing of fuel and space can significantly reduce the formation of particulate matter.

Description of the drawings

Figure 1 is a schematic structural diagram of a piston provided by an embodiment of the present application;

Figure 2 is a schematic structural diagram of the partial structure of the piston shown in Figure 1 when marked;

Figure 3 is an enlarged view of E in Figure 1;

Figure 4 is a schematic structural diagram of another part of the structure of the piston shown in Figure 1;

Figure 5 is a schematic diagram of the path of fuel in a piston provided by an embodiment of the present application (the arrow drawn from the axis of the piston body in the figure represents the fuel sprayed by the injector, and other arrows represent the fuel injected into the side wall of the combustion chamber and then burned through the The path of the fuel after being guided by the side wall of the chamber);

Figure 6 is a simulation cloud diagram of the mixture distribution in the combustion chamber when the engine uses the piston provided by this application;

Figure 7 is a simulation cloud diagram of the mixture distribution in the combustion chamber when the engine uses a piston other than that of this embodiment.

Icon: 1-piston body; 2-combustion chamber; 3-convex portion; 21-first ring groove; 22-second ring groove; 221-outside wall; 222-bottom wall; 23-third ring groove; 231 -Arc-shaped concave portion; 232-Planar portion; 233-Arc-shaped convex portion; 24-Boss; 4-First circle; 5-Second circle.

Detailed ways

The existing combustion chamber can effectively organize the mixing of oil and gas inside it, but the utilization rate of the air in the peripheral area of the combustion chamber is very low. If the diameter of the existing combustion chamber at the top surface of the piston is increased to bring the outer edge of the combustion chamber as close as possible to the outer edge of the piston, a large amount of oil-gas mixture will inevitably burn close to the inner wall of the cylinder liner, resulting in oil burning and piston enlargement. The wear of the ring and cylinder liner, the increase in soot (soot) emissions from the engine, increase the collection pressure of the after-treatment, increase the exhaust back pressure of the engine, and increase the cost of the after-treatment. At the same time, the increase in engine exhaust back pressure in turn reduces the engine's fuel economy. Since the existing combustion chamber cannot fully utilize the air near the edge of the combustion chamber, the heat release rate is relatively low when the diesel engine is working (when the crankshaft angle is about 8° to 30°), resulting in a relatively low thermal efficiency of the engine.

As shown in Figure 1, a piston provided in this embodiment includes a piston body 1, a combustion chamber 2 is provided at the top of the piston body 1, and a boss 3 is provided at the bottom of the combustion chamber 2; the combustion chamber 2 is included in the piston body 1 The bottom of the first annular groove 21, the second annular groove 22 and the third annular groove 23 are arranged sequentially in the direction of the top of the piston body 1. The first annular groove 21, the second annular groove 22 and the third annular groove 23 are The caliber increases sequentially, the first annular groove 21, the second annular groove 22 and the third annular groove 23 are coaxial and connected with each other, and the first annular groove 21, the second annular groove 22 and the third annular groove 23 all surround the bulge Part 3 settings;

As shown in FIG. 2 , the second annular groove 22 includes an annular outer wall 221 and an outer There is a bottom wall 222 inside the wall 221 and connected to the outer wall 221. A boss 24 extending in the direction of the axis of the piston body 1 is formed between the bottom wall 222 and the first annular groove 21;

The third ring groove 23 includes an arc-shaped concave portion 231. The inner end of the arc-shaped concave portion 231 is connected to an end of the outer wall 221 away from the bottom wall 222. The outer end of the arc-shaped concave portion 231 is connected to the top surface of the piston body 1; engine During operation, the arc-shaped concave portion 231 can form an air interlayer F between the mixed gas (as shown in Figures 5 and 6, where the air interlayer is not numbered in Figure 6).

The piston provided in this embodiment includes a piston body 1 with a combustion chamber 2 at the top. The combustion chamber 2 is provided with a protrusion 3 at the bottom. The combustion chamber 2 is included in the direction from the bottom of the piston body 1 to the top of the piston body 1. The first annular groove 21, the second annular groove 22 and the third annular groove 23 are arranged and have their diameters increased sequentially. The first annular groove 21, the second annular groove 22 and the third annular groove 23 are coaxial and connected with each other, and are evenly spaced. Set around the raised portion 3. The second annular groove 22 includes an annular outer wall 221 and a bottom wall 222 located inside the outer wall 221 and connected to the outer wall 221 . An axis directed toward the piston body 1 is formed between the bottom wall 222 and the first annular groove 21 . The boss 24 extends in the same direction. The fuel injected onto the wall of the combustion chamber 2 can be effectively guided by the kinetic energy of the fuel itself and the second annular groove 22 , and then the fuel beam is guided to the space of the third annular groove 23 . The third ring groove 23 includes an arc-shaped concave portion 231. The inner end of the arc-shaped concave portion 231 is connected to an end of the outer wall 221 of the second ring groove 22 away from the bottom wall 222 of the second ring groove 22. The outer end is connected to the top surface of the piston body 1. During the operation of the piston, when it reaches a predetermined position (for example, when the piston moves to near the top dead center of the engine), a strong squeezing flow will be formed from the outer edge to the center of the combustion chamber 2. This strong squeezing flow will guide the flow from the second annular groove 22 The incoming fuel flows toward the center of the combustion chamber 2, and finally forms a relatively uniform mixture in the upper space of the second annular groove 22 and the third annular groove 23, making full use of the turbulence in the combustion chamber 2, and creates a mixture between the second annular groove 22 and the third annular groove 23. The upper space of the annular groove 23 forms a mixture for combustion, so that the piston provided in this embodiment can fully utilize the space of the combustion chamber 2 and form a uniform mixture inside the entire combustion chamber 2 . Making full use of the space of the combustion chamber 2 for mixing and combustion can fully increase the heat release rate of the entire combustion process, especially the heat release rate when the crankshaft angle is 8° to 30°, thus improving the engine thermal efficiency and engine fuel economy.

At the same time, during engine operation, under the interaction of the strong squeezing flow at the edge of the piston and the oil jet, an air interlayer will be formed between the arc-shaped concave portion 231 of the third annular groove 23 and the mixture (as shown in Figures 5 and 6 (shown), the air interlayer can reduce heat loss, effectively reduce the heat transfer loss of the piston, improve thermal efficiency, and further reduce engine fuel consumption.

In addition, the piston provided in this embodiment fully utilizes the space of the entire combustion chamber 2 to form a uniform mixture. In this way, the fuel-rich area is reduced during the combustion process, and the high-temperature combustion area inside the combustion chamber 2 is reduced. Therefore, it is possible to The formation of nitrogen oxides is significantly reduced, and sufficient mixing of fuel and space can significantly reduce the formation of particulate matter.

As shown in Figure 7, after simulation, if the third annular groove 23 is a tapered surface, no matter how the angle between the third annular groove 23 and the top surface of the piston body 1 is set, the air interlayer in this embodiment cannot be formed. , that is, the effects of reducing heat loss, reducing piston heat transfer loss, and improving thermal efficiency cannot be achieved.

Along the axis direction of the piston body 1, the distance H0 between the top of the protrusion 3 and the top surface of the piston body 1 is related to the protrusion amount of the injector and can be set according to actual needs. Moreover, those skilled in the art know that the protrusion The top of the rising portion 3 is lower than the top surface of the piston body 1 .

The bottom of the combustion chamber 2 is provided with a protruding portion 3. In an optional implementation, the protruding portion 3 is provided at the center of the bottom of the combustion chamber 2. The first annular groove 21, the second annular groove 22, and the third annular groove 23 and the axis of the protrusion 3 can be coincident with the axis of the piston body 1 .

When specifically setting the above-mentioned raised portion 3, in an optional implementation, the raised portion 3 includes a truncated cone portion disposed at the bottom of the combustion chamber 2 and located in the combustion chamber 2, and a truncated cone portion disposed on the truncated cone portion facing the top surface of the piston body 1. As for the spherical portion on one side, the cone angle α of the truncated cone portion is 92° to 96°, and the radius R0 of the spherical portion is 15 to 20 mm.

It should be noted that the diameter of the first annular groove 21 mentioned in this embodiment refers to the diameter of the end of the first annular groove 21 away from the bottom of the piston body 1 , and the diameter of the second annular groove 22 refers to the diameter of the second annular groove 22 . 22 is the diameter of the end of the third annular groove 23 away from the first annular groove 21 , and the diameter of the third annular groove 23 refers to the diameter of the end of the third annular groove 23 away from the second annular groove 22 .

A boss 24 extending in the direction of the axis of the piston body 1 is formed between the bottom wall 222 of the second ring groove 22 and the first ring groove 21. In order to facilitate processing, it can also play a role in controlling the fuel injected onto the boss 24. For better guiding effect, when specifically setting the above-mentioned boss 24, in an optional implementation manner, the boss 24 is a curved boss.

Please continue to refer to FIG. 1 . In an optional implementation, the diameter D1 of the portion of the boss 24 closest to the axis of the piston body 1 is 50% to 55% of the outer diameter of the piston body 1 .

In an optional implementation, the boss 24 is an arcuate boss. Along the axis direction of the piston body 1, on the longitudinal section of the piston body 1 (that is, the section passing through the axis of the piston body 1), the arcuate boss is The distance between the center of the circle where the arc surface is located and the lowest part of the first ring groove 21 is H1, H1 It is 7% to 8% of the outer diameter of the piston body 1 , so that the first annular groove 21 can utilize the air in the combustion chamber 2 more effectively.

For example, the radius R1 of the arcuate boss may be 2.5-3.5 mm, for example, 3 mm.

In order to better guide the oil-air mixture injected onto it, in an optional implementation, as shown in Figures 2 and 3, the third annular groove 23 includes a flat portion 232 and an arc-shaped convex portion. 233, the inner end of the flat part 232 is connected with the second annular groove 22, the outer end of the flat part 232 is connected with the inner end of the arc concave part 231; the inner end of the arc convex part 233 is connected with the outer end of the arc concave part 231 The outer end of the arc-shaped convex portion 233 is connected to the top surface of the piston body 1 .

In an optional implementation, the outer side wall 221 of the second annular groove 22 is perpendicular to the top surface of the piston body 1;

Please continue to refer to Figure 2. In the radial direction of the piston body 1, the distance between the outer end of the flat portion 232 and the outer wall 221 of the second annular groove 22 is W3, and the outer end of the arc-shaped convex portion 233 and the second The distance between the outer side walls 221 of the annular groove 22 is W4, and the value of W4/W3 is 3 to 4 (that is, the ratio of W4 to W3 is 3 to 4), thereby further improving the efficiency of the third annular groove 23 to be sprayed thereon. The guiding effect of the oil-gas mixture.

The third annular groove 23 includes a flat portion 232 and an arc-shaped convex portion 233. In an optional implementation, the radius R4 of the arc-shaped concave portion 231 is 2 to 3 times the radius R5 of the arc-shaped convex portion 233, for example: R4 is 2.5 times that of R5.

The depth H4 of the third ring groove 23 is 2.5% to 4.5% of the thickness of the piston body 1;

The diameter D3 of the third annular groove 23 (that is, the diameter of the third annular groove 23 at the connection point between the arc-shaped convex portion 233 and the top surface of the piston body 1) is 80% to 90% of the outer diameter of the piston body 1.

In some embodiments, the above-mentioned radius R4 is 2 to 3 times the radius R5 of the arc-shaped convex portion 233 , the depth H4 is 2.5% to 4.5% of the thickness of the piston body 1 , and the diameter D3 is 80% of the outer diameter of the piston body 1 There are three size relationships of % to 90%, and you can have only one of them, any two of them, or three of them at the same time.

The above arrangement of the third ring groove 23 is more conducive to the formation of an air interlayer between the arc-shaped concave portion 231 and the mixture.

In an optional implementation, if the boss 24 formed between the bottom wall 222 of the second ring groove 22 and the first ring groove 21 is an arc boss, then:

The part with the smallest inner diameter of the arc boss is the throat; on the same radius of the piston body 1, the first The distance between the farthest part of the annular groove 21 from the axis of the piston body 1 and the corresponding part of the throat is d. When the outer diameter of the piston body 1 is less than or equal to 150 mm, d is 0.5%~ of the outer diameter of the piston body 1 1%;

Alternatively, in the longitudinal section of the piston body 1, the distance f between the center of the circle where the arc surface of the arcuate boss is located and the lowest part of the first annular groove 21 in the axial direction of the piston body 1 is 9 to 10 times d.

Of course, the above d is 0.5% to 1% of the outer diameter of the piston body 1 and the distance f is 9 to 10 times d, which can also be used together in the same embodiment.

The above arrangement of the first annular groove 21 makes it difficult for the oil jet ejected from the injector to overlap with the air-fuel mixture rolled back by the first annular groove 21 , thereby improving the uniformity of the oil-air mixture inside the first annular groove 21 .

In an optional implementation, the outer wall 221 of the second annular groove 22 is perpendicular to the top surface of the piston body 1. On the same radius of the piston body 1, the part of the boss 24 closest to the axis of the piston body 1 is in contact with the second ring groove 22. The distance W2 (as shown in Figure 4) between the outer side walls 221 of the annular groove 22 is 4% to 5% of the outer diameter of the piston body 1, so as to better guide the fuel injected onto the boss 24. .

In an optional implementation, the outer side wall 221 of the second ring groove 22 is connected to the third ring groove 23 through the first fillet R3, and is connected to the bottom wall 222 through the second fillet R2. The third ring groove 23 includes Planar portion 232, the inner end of the planar portion 232 is connected to the second annular groove 22, and the outer end of the planar portion 232 is connected to the inner end of the arc concave portion 231; along the axis direction of the piston body 1, the planar portion 232 is connected to the second annular groove 22. The distance H3 between the centers of the fillets R2 is 1.1% to 1.3% of the outer diameter of the piston body 1; for example, R2 is larger than R3, and R3 is as small as possible, for example: R2=1.5mm, R3=1mm.

In an optional implementation, the diameter D2 at the outer side wall 221 of the second annular groove 22 is 55% to 65% of the outer diameter of the piston body 1;

In an optional implementation, the bottom wall 222 of the second annular groove 22 includes a tapered surface, and the angle b between the tapered surface and the top surface of the piston body 1 is 8° to 25°. The bottom wall 222 of the second annular groove 22 has an inclined structure, which is beneficial to fuel guidance.

The above-mentioned arrangement of the second annular groove 22 is more conducive to guiding the oil-air mixture injected onto it upward, and is conducive to improving the mixing uniformity of the oil-air mixture.

In order to improve the uniformity of the oil-air mixture, in an optional implementation, the distance H2 between the lowest part of the first annular groove 21 and the top surface of the piston body 1 is the outer diameter of the piston body 1 13% to 20%.

Further, in an optional implementation, the first annular groove 21 includes a first circular arc segment and a second circular arc segment that are smoothly connected. The first circular arc segment is located at the bottom of the first annular groove 21 and the second circular arc segment is located at the bottom of the first annular groove 21 . The arc segment connects the first arc segment and the second annular groove 22;

The circle where the first arc segment is located is the first circle 4, the circle where the second arc segment is located is the second circle 5, the second circle 5 is located in the first circle 4 and is tangent to the first circle 4, and The center of the first circle 4 is closer to the axis of the piston body 1 than the center of the second circle 5; between the part of the first circle 4 closest to the axis of the piston body 1 and the part of the second circle 5 farthest from the axis of the piston body 1 The distance is W1, and the value of W1/H1 is 1.65~1.9.

The value of W1/H1 is 1.65~1.9, which makes it difficult for the oil jet ejected from the injector in the early stage of combustion of the engine to overlap with the mixed gas recirculated from the first annular groove 21, which can improve the mixing of oil and gas inside the first annular groove 21. Uniformity can effectively improve the heat release rate in the early stage of combustion, improve thermal efficiency, and reduce fuel consumption rate; at the same time, the oil and gas are evenly mixed in the first ring groove 21, which can effectively reduce soot emissions.

In the piston provided in this embodiment, the combustion chamber 2 includes three annular grooves, which improves the full utilization of air in each area inside the combustion chamber 2 by forcibly dividing the oil-air mixture into different circulation paths (as shown in Figure 5). At the same time, the design of multiple ring grooves can form multiple oil jets through steps between ring grooves, which is conducive to the complete mixing of oil and gas. The outermost ring groove (the third ring groove 23 in this embodiment) in the multi-ring groove design can make full use of the air near the outer edge of the combustion chamber 2 close to the inner wall of the cylinder liner; improving the uniformity of the oil-gas mixture inside the combustion chamber 2 sex. In this embodiment, the three-ring groove design of the piston can make full use of the squeezing flow generated when the piston is compressed to make the oil-air mixture flow more easily toward the center of the combustion chamber 2, avoiding oil burning and wear caused by the mixture burning close to the inner wall of the cylinder liner. Reliability problems such as aggravation; at the same time, the optimized annular groove design can take advantage of the squeezing flow at the edge of the piston and the interaction of the oil beam to form an air interlayer between the mixture and the third annular groove 23 of the piston. The air interlayer can effectively reduce the piston heat transfer loss, further reducing engine fuel consumption.

In addition, the design of the annular groove of the combustion chamber 2 in this embodiment makes it easier for the combustion chamber 2 to match the air passage. Regardless of the arrangement of the air passage, the swirl ratio intensity can be easily optimally matched to the combustion chamber 2.

This embodiment provides an engine including the above-mentioned piston.

The engine provided by this embodiment includes the above-mentioned piston. Therefore, it can at least achieve the technical effects that the above-mentioned piston can achieve, and the technical effects will not be described again here.

The engine provided in this embodiment can further improve the thermal efficiency of the diesel engine and reduce the engine fuel consumption on the premise of meeting the National VI emissions.

It should be noted that the engine mentioned in this embodiment may be a diesel engine or a gasoline engine.

Claims

A piston includes a piston body (1), a combustion chamber (2) is provided at the top of the piston body (1), and a protrusion (3) is provided at the bottom of the combustion chamber (2); the combustion chamber (2) It includes a first annular groove (21), a second annular groove (22) and a third annular groove arranged sequentially in the direction from the bottom of the piston body (1) to the top of the piston body (1). (23), the diameters of the first annular groove (21), the second annular groove (22) and the third annular groove (23) increase in sequence, the first annular groove (21), the The second ring groove (22) and the third ring groove (23) are coaxial and connected with each other, and the first ring groove (21), the second ring groove (22) and the third ring groove The grooves (23) are all arranged around the raised portion (3);

Wherein, the second annular groove (22) includes an annular outer wall (221) and a bottom wall (222) located inside the outer wall (221) and connected to the outer wall (221). A boss (24) extending in the direction of the axis of the piston body (1) is formed between the wall (222) and the first annular groove (21);

The third annular groove (23) includes an arc-shaped concave portion (231), and the inner end of the arc-shaped concave portion (231) is connected to an end of the outer wall (221) away from the bottom wall (222). The outer end of the arc-shaped concave portion (231) is connected to the top surface of the piston body (1); during engine operation, the arc-shaped concave portion (231) can form an air interlayer with the mixture.
The piston according to claim 1, wherein the diameter of the portion of the boss (24) closest to the axis of the piston body (1) is 50% to 55% of the outer diameter of the piston body (1).
The piston according to claim 1, wherein the boss (24) is a curved boss, along the axis direction of the piston body (1), on the longitudinal section of the piston body (1), the The distance between the center of the circle where the arc surface of the arc surface boss is located and the lowest part of the first annular groove (21) is H1, and H1 is 7% to 8% of the outer diameter of the piston body (1). .
The piston according to claim 1, wherein the third annular groove (23) includes a flat portion (232) and an arc-shaped convex portion (233), and the inner end of the flat portion (232) is in contact with the second The annular groove (22) is connected, the outer end of the flat part (232) is connected with the inner end of the arc-shaped concave part (231); the inner end of the arc-shaped convex part (233) is connected with the arc-shaped concave part The outer end of the arc-shaped convex portion (233) is connected to the top surface of the piston body (1).
The piston according to claim 4, wherein the outer wall (221) of the second annular groove (22) is perpendicular to the top surface of the piston body (1);

In the radial direction of the piston body (1), the distance between the outer end of the flat portion (232) and the outer wall (221) of the second annular groove (22) is W3, and the arc The distance between the outer end of the convex portion (233) and the outer wall (221) of the second annular groove (22) is W4, and the value of W4/W3 is 3-4.
The piston according to claim 4, further comprising at least one of the following solutions:

The radius of the arc-shaped concave portion (231) is 2 to 3 times the radius of the arc-shaped convex portion (233);

The depth of the third annular groove (23) is 2.5% to 4.5% of the thickness of the piston body (1);

The diameter of the third annular groove (23) is 80% to 90% of the outer diameter of the piston body (1).
The piston according to claim 3, further comprising at least one of the following solutions:

The part with the smallest inner diameter of the arc boss is the throat. On the same radius of the piston body (1), the part of the first annular groove (21) farthest from the axis of the piston body (1) is the same as that of the piston body (1). The distance between the corresponding parts of the throat is d. When the outer diameter of the piston body (1) is less than or equal to 150 mm, d is 0.5% to 1% of the outer diameter of the piston body (1);

In the longitudinal section of the piston body (1), the center of the circle where the arc surface of the arcuate boss is located and the lowest part of the first annular groove (21) are in the axial direction of the piston body (1). The distance above is 9 to 10 times of d.
The piston according to claim 5, further comprising at least one of the following solutions:

On the same radius of the piston body (1), the distance between the part of the boss (24) closest to the axis of the piston body (1) and the outer wall (221) is the distance of the piston body (221) 1) 4% to 5% of the outer diameter;

The outer side wall (221) of the second annular groove (22) is connected to the third annular groove (23) through a first fillet and connected to the bottom wall (222) through a second fillet; along the The distance between the flat part (232) and the center of the second fillet in the axial direction of the piston body (1) is 1.1% to 1.3% of the outer diameter of the piston body (1);

The diameter of the outer wall (221) of the second annular groove (22) is 55% to 65% of the outer diameter of the piston body (1);

The bottom wall (222) of the second annular groove (22) includes a tapered surface, and the angle between the tapered surface and the top surface of the piston body (1) is 8° to 25°.
The piston according to any one of claims 1-8, wherein the first annular groove (21) The distance between the lowest part and the top surface of the piston body (1) is 13% to 20% of the outer diameter of the piston body (1).
The piston according to claim 3, wherein the first annular groove (21) includes a first arc segment and a second arc segment that are smoothly connected, and the first arc segment is located in the first annular groove. (21) at the bottom, the second arc segment connects the first arc segment and the second annular groove (22);

The circle where the first arc segment is located is the first circle (4), the circle where the second arc segment is located is the second circle (5), and the second circle (5) is located on the first in the circle (4) and tangent to the first circle (4), and the center of the first circle (4) is closer to the center of the piston body (1) than the center of the second circle (5) Axis; the distance between the part of the first circle (4) closest to the axis of the piston body (1) and the part of the second circle (5) farthest from the axis of the piston body (1) is W1, and the value of W1/H1 is 1.65~1.9.
The piston according to any one of claims 1 to 8, wherein the raised portion (3) includes a truncated cone portion disposed at the bottom of the combustion chamber and located in the combustion chamber, and a truncated cone portion disposed toward the bottom of the combustion chamber. As for the spherical portion on one side of the top surface of the piston body (1), the cone angle of the truncated cone portion is 92° to 96°, and the radius of the spherical portion is 15 to 20 mm.
An engine including the piston according to any one of claims 1-11.