CN217481414U - Arc top piston top, arc top piston and combustion chamber - Google Patents

Abstract

The utility model provides an arc top piston top, arc top piston and combustion chamber, arc top piston top includes: the arc pit area is a bowl-shaped pit and is positioned at the center of the top of the arc-top piston; the height of the first end of the conical surface convex area is higher than that of the second end of the conical surface convex area, the first end of the conical surface convex area is contacted with the outer edge of the arc pit area, and the second end of the conical surface convex area extends to the edge of the top of the arc top piston; the two conical surface convex areas are respectively positioned on the front side and the rear side of the arc pit area, and the two conical surface convex areas are symmetrically arranged relative to the arc pit area. The arc top piston top can be applied to a large-cylinder-diameter high-compression-ratio engine, the air flow movement speed in the air inlet stroke of the engine can be increased to a large extent, the compression stroke and the turbulent kinetic energy at the tail end of the compression stroke are improved, and the detonation phenomenon of the large-cylinder-diameter high-compression-ratio engine in the related technology is effectively solved.

Description

Arc top piston top, arc top piston and combustion chamber

Technical Field

The utility model relates to an engine field especially relates to an arc top piston top, arc top piston and combustion chamber.

Background

The engine is a main emission source of atmospheric pollutants and is also an important source of carbon emission, the annual average petroleum consumption of the engine accounts for more than 60% of the total petroleum consumption in China, and the carbon dioxide emission of the engine exceeds 10% of the total carbon emission in China. With the continuous promotion of the green development concept, the engine faces the challenge of increasingly strict emission and oil consumption regulations, and the development of a high-thermal-efficiency near-zero-emission engine becomes the primary target of the academic and engineering circles. At present, the development of gasoline engines with high thermal efficiency mainly depends on technical means such as high compression ratio, external cooling EGR (exhaust gas recirculation), low friction loss and the like. Compared with a diesel engine, the large-displacement gasoline engine has the advantages of low noise, low cost and the like, and has larger market space in the market-dividing fields of high-end business buses, large pickup trucks and the like. Compared with a complex V-shaped multi-cylinder arrangement type, the scheme with the in-line large cylinder diameter has the advantage of cost. However, for a large-cylinder-diameter gasoline engine, the flame propagation distance is longer, the knocking tendency is greater, and the technical challenge of realizing efficient development in combination with technologies such as high compression ratio and the like exists. The technical reasons lead the development of the in-line large-cylinder-diameter high-efficiency gasoline engine to be very difficult.

The piston top is an important component in an engine combustion chamber, and directly influences the mixing uniformity, flame propagation speed, heat release rate, heat transfer loss and knocking tendency of the engine, so that the performance of the engine is influenced. The origin of knocking is that the tail end mixed gas is self-ignited, and the larger the cylinder diameter is, the higher the compression ratio is, the greater the knocking tendency is.

The top of the piston of the conventional PFI gasoline engine is mostly designed to be flat, so that the efficient organization of oil-gas mixing and the improvement of turbulent kinetic energy distribution are difficult, the detonation phenomenon is easily caused, the power of the engine is reduced, and the fuel economy of the engine is poor. In some models, an irregular pit is constructed in the center of the top of a piston and acts with other structures together, so that airflow enters a combustion chamber to form a plane vortex, turbulent kinetic energy is enhanced, quality of mixed gas is improved, and knocking tendency is reduced.

In addition, the top of the existing special-shaped piston is generally designed into an irregular shape, is difficult to realize by processing, can only be formed by casting, has poor surface roughness, causes certain loss to intake tumble, and simultaneously needs to be cooperatively applied with direct injection (GDI) in a cylinder, so that certain problems exist in the application of the special-shaped piston to a PFI gasoline engine with a large cylinder diameter.

Therefore, how to improve the flow of mixed gas in a combustion chamber of the engine by further optimizing the top structure of the piston, effectively inhibit the knocking tendency of the gasoline engine with a large cylinder diameter and a high compression ratio, and realize the autonomous design and development of the in-line large-cylinder-diameter high-efficiency engine is a technical problem which needs to be solved urgently at present.

SUMMERY OF THE UTILITY MODEL

Technical problem to be solved

The prior art generally adopts methods of accelerating combustion speed, reducing in-cylinder temperature and the like to inhibit knocking. The inventor finds that the mixing of the fuel and the air in the cylinder can be effectively enhanced by optimizing the structure of the combustion chamber, the combustion speed is accelerated, the knocking is inhibited, and the EGR tolerance is improved. The applicant finds that through research, the structure of the combustion chamber at the top of the piston is optimized, the flow of mixed gas in a cylinder can be better improved, the tumble ratio and the turbulent kinetic energy of the combustion chamber are improved, the knocking tendency of a large-cylinder-diameter high-compression-ratio gasoline engine is effectively inhibited, the flame propagation speed is accelerated, the combustion duration is shortened, the combustion stability is improved, and the dynamic property and the economical efficiency of an engine are finally improved. The utility model provides an arc top piston top and use its arc top piston and combustion chamber to solve the problem that exists among the above-mentioned prior art at least.

(II) technical scheme

To achieve the above object, the present invention provides an arc crown piston top, including: the arc pit area is a bowl-shaped pit and is positioned at the center of the top of the arc-top piston; the first ends of the conical surface convex areas are higher than the second ends of the conical surface convex areas, the first ends of the conical surface convex areas are in contact with the outer edge of the arc-shaped pit area, and the second ends of the conical surface convex areas extend to the edge of the top of the arc-top piston; the two conical surface convex areas are respectively positioned on the front side and the rear side of the arc pit area, and the two conical surface convex areas are symmetrically arranged relative to the arc pit area.

In some embodiments of the present invention, the system further comprises:

the first flat top area is a plane, one end of the first flat top area is in contact with the outer edge of the left side of the arc-shaped pit area, the other end of the first flat top area extends to the edge of the top of the arc-shaped top piston, and the first flat top area is located between the two conical surface convex areas;

and the second flat top area is a plane and is coplanar with the first flat top area, one end of the second flat top area is contacted with the outer edge of the right side of the arc-shaped pit area, the other end of the second flat top area extends to the edge of the top of the arc-shaped top piston, and the second flat top area is positioned between the two conical surface convex areas.

In some embodiments of the present invention, the outer edge of the arc pit area reaches the vertical distance at the bottom of the arc pit area is 5-7 mm, and the radius of the arc pit area is 75-85 mm.

In some embodiments of the present invention, an included angle between a conical generatrix of the conical convex region and a plane of the first flat top region or the second flat top region is 18 ° to 22 °.

In some embodiments of the present invention, the first plateau region comprises:

the two inlet valve avoiding areas are arc-shaped pits and are respectively arranged at the intersection of the first flat top area and the two conical surface convex areas; wherein, the included angle between the normal line of the bottom of the arc-shaped concave pit in the two inlet valve avoiding areas and the vertical direction is 17-20 degrees.

In some embodiments of the present invention, the second flat top region comprises:

the two exhaust valve avoiding areas are arc-shaped pits and are respectively arranged at the intersection of the second flat top area and the two conical surface convex areas; wherein, the included angle between the pit bottom normal of the arc-shaped pit in the two exhaust valve avoiding areas and the vertical direction is 20-24 degrees.

The utility model also provides an arc top piston, include:

a crown piston crown as disclosed above;

the outer diameter of the head is the same as that of the top of the arc top piston, the outer diameter is 95-100 mm, and the head is located below the top of the arc top piston;

and the skirt part is fixedly connected with the lower part of the head part.

In some embodiments of the invention, the head comprises:

the oil guide groove is formed in the outer ring of the head part;

and the piston ring is sleeved in the oil guide groove.

In some embodiments of the invention, the skirt further comprises

And the connecting rod pin hole is suitable for rotatably connecting the connecting rod of the arc top piston.

The utility model also provides a combustion chamber, include:

a cylinder wall;

the arc top piston is arranged inside the cylinder wall and is coaxially and slidably connected with the cylinder wall;

and the cylinder cover is fixedly connected with the upper opening of the cylinder wall and forms a closed cavity with the cylinder wall.

(III) advantageous effects

According to the technical solution, the arc top piston and the combustion chamber using the same of the present invention have at least one or one of the following beneficial effects:

(1) the utility model provides an arc pit area at arc top piston top and the structure of two conical surface protruding districts can optimize the interior airflow motion form of jar to a great extent, increase the air current velocity of motion among the engine intake stroke, can be applied to the development of big jar footpath high efficiency engine on, effectively solve the detonation phenomenon of big jar footpath high compression ratio engine among the correlation technique.

(2) The conical surface convex area and the flat top area can jointly realize the optimization of the air flow motion form to form a larger-scale tumble, the piston compression process can lead the tumble to be broken and converted into stronger turbulent kinetic energy during the work doing period of the combustion chamber, the combustion is accelerated, the detonation tendency is obviously improved, the application problem of the high compression ratio technology of the large-cylinder-diameter engine is solved, and the fuel economy of the engine can be effectively improved.

(3) The utility model provides an arc top piston top and conical surface protruding structure through matcing in coordination with the engine air flue, does not rely on the GDI system, is applicable to the air flue injection (PFI) that the cost is lower. The application working condition limit of the high compression ratio technology of the traditional air passage injection PFI gasoline engine can be effectively expanded, and the inhibition of knocking and the improvement of fuel economy can be realized under lower injection pressure.

(4) The utility model provides a marginal structure at arc top piston top can make the fuel in the combustion chamber form the torrent at the marginal zone at piston top, especially is adapted to the design of big jar footpath, can effectively strengthen sensitive region's such as combustion chamber outer fringe fuel flow and heat transfer, improves the detonation tendency.

(5) The utility model provides a structure at arc top piston top easily uses mirror finish manufacturing, and reducible flow loss, and then increase the mobile intensity of fuel in the jar promotes combustion speed, reduces fuel consumption, strengthens the low-speed dynamic of engine, improves whole car driving sense and fuel economy.

Drawings

Fig. 1 is a perspective view of a crown of an arc-topped piston in an embodiment of the invention;

fig. 2 is a top view of a curved crown piston crown in an embodiment of the invention;

FIG. 3 is a cross-sectional view taken along A-A of FIG. 2;

FIG. 4 is a cross-sectional view taken along line B-B of FIG. 2;

FIG. 5 is a cross-sectional view taken along the line C-C of FIG. 2;

fig. 6 is a front view of a curved top piston in an embodiment of the invention;

FIG. 7 is a perspective view of a flat-top combustor;

FIG. 8 is a perspective view of a contoured combustion chamber;

fig. 9 is a graph comparing transient tumble flows of an arc top piston combustion chamber with a conventional flat top piston combustion chamber in an embodiment of the present invention;

fig. 10 is a graph comparing transient turbulence energy of a curved topped piston combustion chamber with a conventional flat topped piston combustion chamber in an embodiment of the invention.

[ description of the main reference numerals in the drawings ] for the embodiments of the present invention

1-a first plateau region;

2-arc pit area;

3-a conical surface convex area;

31-a first end of a conical raised region;

32-a second end of the pyramidal convex region;

4-an exhaust valve avoiding area;

5-an intake valve avoidance zone;

6-a second plateau region;

7-top;

8-a head;

9-a skirt;

10-oil guide grooves;

11-a piston ring;

12-connecting rod pin hole.

Detailed Description

The utility model provides an arc top piston top, arc top piston and combustion chamber, its arc top piston top, include: an arc-shaped pit area and two conical surface convex areas. The arc pit area is a bowl-shaped pit and is positioned at the center of the top of the arc top piston; the first end of the conical surface convex area is higher than the second end of the conical surface convex area, the first end of the conical surface convex area is contacted with the outer edge of the arc pit area, and the second end of the conical surface convex area extends to the edge of the top of the arc top piston; the two conical surface protruding areas are respectively located on the front side and the rear side of the arc-shaped pit area, and the two conical surface protruding areas are symmetrically arranged relative to the arc-shaped pit area. The arc-top piston top can be applied to a large-cylinder-diameter high-compression-ratio engine, can increase the air flow movement speed in the air inlet stroke of the engine to a greater extent, improves the compression stroke and turbulent kinetic energy at the tail end of the compression stroke, and effectively solves the knocking phenomenon of the large-cylinder-diameter high-compression-ratio engine in the related technology.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in detail with reference to the accompanying drawings. The present invention may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity, and like reference numerals designate like elements throughout.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. It should be understood that the description is illustrative only and is not intended to limit the scope of the present invention. In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the embodiments of the invention. It may be evident, however, that one or more embodiments may be practiced without these specific details. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The terms "comprises," "comprising," and the like, as used herein, specify the presence of stated features, steps, operations, and/or components, but do not preclude the presence or addition of one or more other features, steps, operations, or components.

All terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless otherwise defined. It is noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of this specification and should not be interpreted in an idealized or overly formal sense.

Where a convention analogous to "at least one of A, B and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B and C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.). Where a convention analogous to "A, B or at least one of C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B or C" would include but not be limited to systems that have a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B, C together, etc.).

The utility model provides an arc top piston top, as shown in figure 1, this arc top piston top includes: an arc-shaped pit area 2 and two conical convex areas 3. The arc pit area 2 is a bowl-shaped pit and is positioned at the center of the top of the arc top piston. The first end 31 of the conical surface convex area is higher than the second end 32 of the conical surface convex area, the first end 31 of the conical surface convex area is contacted with the outer edge of the arc pit area 2, and the second end 32 of the conical surface convex area extends to the edge of the top of the arc top piston; the two conical surface convex areas 3 are respectively positioned on the front side and the rear side of the arc pit area 2, and the two conical surface convex areas 3 are symmetrically arranged relative to the arc pit area 2.

The combined design of the arc-shaped pit area 2 and the conical surface convex area 3 can increase the airflow movement speed in the air inlet stroke of the engine to a greater extent.

As shown in fig. 1 and 2, the arc-top piston top further includes: a first plateau 1 and a second plateau 6. The first flat top area 1 is a plane, one end of the first flat top area 1 is in contact with the outer edge of the left side of the arc-shaped pit area 2, the other end of the first flat top area 1 extends to the edge of the top of the arc-shaped piston, and the first flat top area 1 is located between the two conical surface convex areas 3. The second flat top area 6 is a plane and is coplanar with the first flat top area 1, one end of the second flat top area 6 is contacted with the outer edge of the right side of the arc-shaped pit area 2, the other end of the second flat top area 6 extends to the edge of the top of the arc-shaped top piston, and the second flat top area 6 is positioned between the two conical surface convex areas 3.

The conical surface convex area 3 can be combined with the flat top area, the optimization of the air flow motion form is realized, large-scale tumble flow is formed, the tumble flow can be broken and converted into stronger turbulent kinetic energy in the piston compression process during the work doing period of the combustion chamber, the combustion is accelerated, the detonation tendency is further obviously improved, the application problem of the high compression ratio technology of the large-cylinder-diameter engine is solved, and the fuel economy of the combustion chamber of the engine can be effectively improved.

The combined design of the arc pit area 2 and the conical surface bulge can increase the airflow movement speed of the air inlet stroke of the combustion chamber to a greater extent and improve the tumble strength; at the moment of the compression end of the combustion chamber, by means of the special structural design of the conical surface convex area 3 at the top of the piston, tumble flow can be effectively broken and converted into stronger turbulent kinetic energy, and the combustion process is accelerated. Especially in the knock sensitive areas such as the outer edge of the combustion chamber, compared with the traditional technical scheme, the local micro-turbulence can be formed, the flow and heat exchange of the area are effectively enhanced, and the knocking tendency is obviously improved.

As shown in fig. 2 and 3, the first flat top region 1 includes: two intake valve avoidance zones 5. The intake valve avoiding area 5 is an arc-shaped pit, and the two intake valve avoiding areas 5 are respectively arranged at the intersection of the first flat top area 1 and the two conical surface convex areas 3; wherein, the included angle alpha between the normal line of the bottom of the arc-shaped concave pit in the two inlet valve avoiding areas 5 and the vertical direction is 17-20 degrees. The second flat top region 6 includes: two exhaust valve avoidance zones 4. The exhaust valve avoiding zone 4 is an arc-shaped pit, and the two exhaust valve avoiding zones 4 are respectively arranged at the intersection of the second flat top zone 6 and the two conical surface convex zones 3; wherein, the included angle beta between the pit bottom normal of the arc-shaped pit in the two exhaust valve avoiding areas 4 and the vertical direction is 20-24 degrees.

Fig. 4 shows a cross-sectional view of fig. 2 along the direction B-B, in which the vertical distance d from the outer edge of the arc-shaped pit area 2 to the pit bottom of the arc-shaped pit area 2 is 5-7 mm, and the radius R of the arc-shaped pit area 2 is 75-85 mm.

Fig. 5 shows a cross-sectional view along the direction C-C of fig. 2, in which the included angle γ between the generatrix of the conical surfaces of the two conical surface convex regions 3 and the plane of the first flat top region 1 or the second flat top region 6 is 18 ° to 22 °.

The utility model discloses an above-mentioned arc top piston top can form the microturbulence at its marginal zone, effectively strengthens its flow and heat transfer, has improved the detonation tendency greatly.

The utility model also provides a curved roof piston, as shown in figure 6, this curved roof piston includes top 7, head 8 and skirt portion 9 in the preceding. The outer diameter of head 8 is the same with the outer diameter of top 7, and this outer diameter be 95 ~ 100mm, and this head 8 is located top 7 below, and skirt portion 9 links firmly with the below of head 8.

As shown in fig. 6, the head 8 of the arc-topped piston includes: an oil guide groove 10 arranged on the outer ring of the head part 8 and a piston ring 11 sleeved and arranged in the oil guide groove 10.

The skirt portion 9 of the arc top piston includes a connecting rod pin bore 12 for rotatably connecting the connecting rod of the arc top piston. The connecting rod drives the arc top piston to move up and down to do work externally by being connected with a crankshaft of the engine.

The oil guide groove 10 is used for installing a piston ring 11 of the arc top piston to form a lubricating oil path, so that the arc top piston is lubricated. Specifically, the outer ring of the piston ring 11 contacts with the inner wall of the cylinder wall in the combustion chamber, and the piston ring 11 guides the residual fuel on the cylinder wall into the oil guide groove 10 along with the sliding of the arc-top piston to complete the lubrication of the arc-top piston, thereby prolonging the service life of the arc-top piston.

The distance between the first flat top area 1 or the second flat top area 6 of the arc top piston top 7 and the center of the connecting rod pin hole 12 is 32-36 mm.

An air inlet valve avoiding area 5 and an air outlet valve avoiding area 4 of the arc top piston top 7 are areas for ensuring the safety distance between the piston and the air valve, and the whole areas are of arc structures and are respectively intersected with the arc pit area 2, the conical surface convex area 3, the first flat top area 1 and the second flat top area 6. The central normal lines of the inlet valve avoiding area 5 and the exhaust valve avoiding area 4 are coaxial with the central line of the engine valve, wherein the radius of the inlet valve avoiding area 5 is 20-22 mm, and the distance between the bottom of the arc-shaped pit in the inlet valve avoiding area 5 and the connecting rod pin hole 12 is 38-42 mm; the radius of the exhaust valve avoiding area 4 is 17-19 mm, and the distance between the bottom of the arc-shaped pit in the exhaust valve avoiding area 4 and the connecting rod pin hole 12 is 41-45 mm.

The utility model discloses piston diameter scope that arc top piston structure used is 95 ~ 100 mm.

In addition, fig. 7 and 8 respectively show a top-flat combustion chamber perspective view and a special-shaped combustion chamber perspective view in the related art, the top structures of the two pistons cannot be machined, the pistons need to be machined in a casting mode, the casting production process is multiple, the process control is complex, and the rejection rate is high.

What differs from this, the utility model provides a first flat top district 1, the flat top district 6 of second, arc pit district 2 and the protruding district 3 of conical surface in the top 7 of arc top piston can adopt mirror finishing process, and this project organization workable, its roughness of surface precision can reach more than Ra3.2.

The mirror surface processing technology can reduce the flow loss and realize better oil-gas mixing effect. The flow intensity in the cylinder is increased, and the knocking is further improved. By the technical measures, the application problem of the high compression ratio technology of the large-cylinder-diameter gasoline engine can be effectively solved, the fuel consumption rate is effectively reduced, the low-speed power performance is enhanced, and the driving feeling and the fuel economy of the whole vehicle are obviously improved.

The utility model also provides an use the combustion chamber of above-mentioned arc top piston, this combustion chamber includes: cylinder walls, a curved-top piston, and a cylinder head. The arc top piston is arranged in the cylinder wall and is coaxially connected with the cylinder wall in a sliding manner; the cylinder cover is fixedly connected with the upper opening of the cylinder wall and forms a closed cavity with the cylinder wall.

Through the structure that designs into the easy processing's of major scale arc pit district 2 with arc top piston top central area, two conical surface protruding district 3 and first flat top district 1 and the second flat top district 6 combined action simultaneously, can show the optimization air current motion form, form the tumble flow of bigger scale, especially at the combustion chamber compression end moment, rely on conical surface protruding district 3 class of designs at piston top, can effectively make the tumble flow broken, turn into stronger turbulent kinetic energy, the combustion process accelerates, show and improve the detonation tendency, the problem of application of big cylinder diameter gasoline engine high compression ratio technique has been solved, fuel economy nature has effectively been promoted.

As can be seen from fig. 9, the transient tumble ratio of the arc-topped piston combustion chamber of the present invention is significantly higher than that of the conventional flat-topped piston combustion chamber; as can be seen from fig. 10, the transient turbulence energy of the arc crown piston combustion chamber of the present invention is significantly greater than the transient tumble ratio of the conventional flat crown piston combustion chamber. Therefore, the arc top piston combustion chamber has better combustion effect and stronger power of the engine.

The design of the piston top combustion chamber directly influences the oil-gas mixing uniformity, the flame propagation speed, the heat release rate heat transfer loss and the knocking tendency of the engine, and further influences the performance of the engine. Through the design optimization combustion chamber structure, the combustion characteristics of the gasoline engine can be better improved, the tumble ratio and the turbulent kinetic energy of the combustion chamber are improved, the flame propagation speed is accelerated, the combustion duration is shortened, the combustion stability is improved, the detonation tendency is reduced, and finally the dynamic property and the economical efficiency of the engine are improved.

The utility model discloses an use the combustion chamber of above-mentioned arc top piston can not rely on GDI to directly spout the implementation that the system realized the high compression ratio scheme, has effectively reduced system development cost, makes the use of big cylinder diameter high compression ratio gasoline engine in fields such as commercial car possible. The utility model discloses a combustion chamber does not rely on the GDI system, sprays (PFI) research and development to the air flue that the cost is lower, under lower injection pressure, through the optimal design of piston top combustion chamber, matches in coordination with air flue etc. and equally can be applied to high compression ratio model, has effectively promoted the range of application of traditional PFI gasoline engine high compression ratio technique.

It should also be noted that directional terms, such as "upper", "lower", "front", "rear", "left", "right", etc., used in the embodiments are only directions referring to the drawings, and are not intended to limit the protection scope of the present invention. Throughout the drawings, like elements are represented by like or similar reference numerals. In the event of possible confusion for understanding of the present invention, the conventional structure or configuration will be omitted, and the shapes and sizes of the respective components in the drawings do not reflect the actual sizes and proportions, but merely illustrate the contents of the embodiments of the present invention.

Unless otherwise indicated, the numerical parameters set forth in the specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present invention. In particular, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term "about". Generally, the expression is meant to encompass variations of ± 10% in some embodiments, 5% in some embodiments, 1% in some embodiments, 0.5% in some embodiments by the specified amount.

The use of ordinal numbers such as "first," "second," "third," etc., in the specification and claims to modify a corresponding element does not by itself connote any ordinal number of the element or any ordering of one element from another or the order of manufacture, and the use of the ordinal numbers is only used to distinguish one element having a certain name from another element having a same name.

In addition, unless steps are specifically described or must occur in sequence, the order of the steps is not limited to that listed above and may be changed or rearranged as desired by the desired design. The embodiments described above may be mixed and matched with each other or with other embodiments based on design and reliability considerations, i.e., technical features in different embodiments may be freely combined to form further embodiments.

The above-mentioned embodiments, which further illustrate the objects, technical solutions and advantages of the present invention in detail, it should be understood that the above-mentioned embodiments are only examples of the present invention, and are not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. An arc crown piston crown, comprising:

the arc pit area is a bowl-shaped pit and is positioned at the center of the top of the arc-top piston;

the height of the first end of the conical surface convex area is higher than that of the second end of the conical surface convex area, the first end of the conical surface convex area is contacted with the outer edge of the arc pit area, and the second end of the conical surface convex area extends to the edge of the top of the arc top piston; the two conical surface convex areas are respectively positioned on the front side and the rear side of the arc pit area, and the two conical surface convex areas are symmetrically arranged relative to the arc pit area.

2. The curved crown piston crown of claim 1, further comprising:

the first flat top area is a plane, one end of the first flat top area is in contact with the outer edge of the left side of the arc-shaped pit area, the other end of the first flat top area extends to the edge of the top of the arc-shaped top piston, and the first flat top area is located between the two conical surface convex areas;

and the second flat top area is a plane and is coplanar with the first flat top area, one end of the second flat top area is contacted with the outer edge of the right side of the arc-shaped pit area, the other end of the second flat top area extends to the edge of the top of the arc-shaped top piston, and the second flat top area is positioned between the two conical surface convex areas.

3. The curved-topped piston crown as set forth in claim 1, wherein the vertical distance from the outer edge of the curved-shaped pit area to the pit bottom of the curved-shaped pit area is 5 to 7mm, and the radius of the curved-shaped pit area is 75 to 85 mm.

4. The curved-topped piston crown of claim 1, wherein the included angle between the generatrix of the conical surface convex region and the plane of the first flat top region or the second flat top region is 18 ° to 22 °.

5. The curved top piston crown of claim 2, wherein said first flat top area comprises:

the two inlet valve avoiding areas are arc-shaped pits and are respectively arranged at the intersection of the first flat top area and the two conical surface convex areas; wherein, the included angle between the normal line of the bottom of the arc-shaped concave pit in the two inlet valve avoiding areas and the vertical direction is 17-20 degrees.

6. The curved crown piston crown of claim 2, wherein said second flat crown area comprises:

the two exhaust valve avoiding areas are arc-shaped pits and are respectively arranged at the intersection of the second flat top area and the two conical surface convex areas; wherein, the included angle between the normal of the bottom of the arc-shaped pit in the two exhaust valve avoiding areas and the vertical direction is 20-24 degrees.

7. An arc crown piston, comprising:

the curved top piston crown of any one of claims 1 to 6;

the outer diameter of the head is the same as that of the top of the arc top piston, the outer diameter is 95-100 mm, and the head is located below the top of the arc top piston;

and the skirt part is fixedly connected with the lower part of the head part.

8. The arc crown piston of claim 7, wherein the head portion comprises:

the oil guide groove is formed in the outer ring of the head part;

and the piston ring is sleeved in the oil guide groove.

9. The curved crown piston of claim 7, wherein the skirt portion further comprises

And the connecting rod pin hole is suitable for rotatably connecting the connecting rod of the arc top piston.

10. A combustor, comprising:

a cylinder wall;

the arc top piston of any one of claims 7 to 9, disposed inside the cylinder wall in sliding coaxial connection therewith;

and the cylinder cover is fixedly connected with the upper opening of the cylinder wall and forms a closed cavity with the cylinder wall.

Images