CN116857082A - Piston of low-speed two-stroke engine - Google Patents

Piston of low-speed two-stroke engine Download PDF

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Publication number
CN116857082A
CN116857082A CN202310616838.2A CN202310616838A CN116857082A CN 116857082 A CN116857082 A CN 116857082A CN 202310616838 A CN202310616838 A CN 202310616838A CN 116857082 A CN116857082 A CN 116857082A
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CN
China
Prior art keywords
cooling
hole
cavity
oil
oil return
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Pending
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CN202310616838.2A
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Chinese (zh)
Inventor
夏雨
冯立岩
卢耀
曲文静
方源
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Dalian University of Technology
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Dalian University of Technology
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Application filed by Dalian University of Technology filed Critical Dalian University of Technology
Priority to CN202310616838.2A priority Critical patent/CN116857082A/en
Publication of CN116857082A publication Critical patent/CN116857082A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02F—CYLINDERS, PISTONS OR CASINGS, FOR COMBUSTION ENGINES; ARRANGEMENTS OF SEALINGS IN COMBUSTION ENGINES
    • F02F3/00—Pistons 
    • F02F3/16—Pistons  having cooling means
    • F02F3/20—Pistons  having cooling means the means being a fluid flowing through or along piston
    • F02F3/22—Pistons  having cooling means the means being a fluid flowing through or along piston the fluid being liquid
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/10—Internal combustion engine [ICE] based vehicles
    • Y02T10/12—Improving ICE efficiencies

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Pistons, Piston Rings, And Cylinders (AREA)

Abstract

The invention discloses a low-speed two-stroke engine piston, which comprises a piston rod, a piston head, a piston skirt, a distribution block, an injection disk and an oil return pipe, wherein the piston rod is connected with the piston head through the distribution block; the central cooling cavity of the piston head is communicated with the cooling blind hole; the oil return pipe is arranged in the piston rod and is provided with an oil return channel, and an oil inlet channel is formed between the oil return pipe and the piston rod; the distribution block is arranged at one end of the oil return pipe and is provided with an oil inlet hole, an oil return groove and an oil return hole; the spray disk is provided with a through hole, a side cooling hole and a top cooling hole, a strong convection cavity is formed between the spray disk and the central cooling cavity, and a distribution oil cavity is formed between the spray disk and the distribution block; a gap is reserved at the transition part of the piston head and the jet disc; the oil inlet channel is communicated with the distribution oil cavity through an oil inlet hole, the distribution oil cavity is communicated with the central cooling cavity through a side cooling hole, and the distribution oil cavity is communicated with the strong convection cavity through a top cooling hole; the strong convection cavity is communicated with the central cooling cavity through a gap, the central cooling cavity is communicated with the oil return groove through a through hole, and the oil return groove is communicated with the oil return channel through an oil return hole. The cooling and heat exchanging requirements of the piston of the low-speed two-stroke engine are met.

Description

Piston of low-speed two-stroke engine
Technical Field
The invention relates to the technical field of engines, in particular to a low-speed two-stroke engine piston.
Background
The piston is an important component of the combustion chamber, is one of the core components of the engine, and plays a vital role in the reliable operation of the engine. The working environment of the piston is extremely severe, and the piston is in direct contact with high-temperature and high-pressure fuel gas in the combustion chamber, and simultaneously bears the mechanical load and the high thermal load transferred by the combustion chamber, so that the problems of poor lubrication, difficult cooling and the like are easily caused. When the piston is insufficiently cooled, the temperature of the piston can be excessively high, the mechanical property of the material is reduced, the piston is locally broken or cracked, and the reliable operation of an engine is seriously threatened; the lubricating oil between the piston and the cylinder sleeve is glued to induce the serious fault that the piston pulls the cylinder and the piston ring is blocked; the oil on the top surface is carbonized, which causes a series of problems such as overhigh local temperature, increased thermal stress of the piston, ablation of the top surface, increased emission and the like.
As ships develop larger and larger, the average effective pressure and burst pressure of the low-speed two-stroke engine are continuously increased, so that the pressure and the temperature in the combustion chamber are higher and higher, and higher requirements are put on cooling heat exchange of the piston.
Disclosure of Invention
The invention provides a low-speed two-stroke engine piston, which is used for meeting the higher requirement of the piston on cooling heat exchange.
In order to achieve the above object, the technical scheme of the present invention is as follows:
a low-speed two-stroke engine piston comprises a piston head arranged at the top of a piston rod, a piston skirt arranged around the piston rod and closely connected with the piston head, a distribution block, an injection disk and an oil return pipe;
the piston head is internally provided with a central cooling cavity and a cooling blind hole which is obliquely arranged at the transition part of the top wall and the side wall in the piston head, and the central cooling cavity is communicated with the cooling blind hole;
the oil return pipe is arranged in the piston rod, an oil return channel is arranged in the oil return pipe, and an oil inlet channel is formed between the oil return pipe and the piston rod;
the distribution block is arranged at one end of the oil return pipe and fixedly connected with the piston rod, and is provided with an oil inlet hole, an oil return groove and an oil return hole;
the spray disc is provided with a through hole, a side cooling hole and a top cooling hole, the spray disc is fixedly connected with the distribution block, a strong convection cavity is formed between the top wall of the spray disc and the top wall of the central cooling cavity, and a distribution oil cavity is formed between the spray disc and the distribution block;
gaps are reserved between the transition part of the top wall and the side wall in the piston head and the transition part of the top wall and the side wall of the jet disc;
the oil inlet channel is communicated with the distribution oil cavity through an oil inlet hole, the distribution oil cavity is communicated with the central cooling cavity through a side cooling hole with the axis facing the bottom of the cooling blind hole, and the distribution oil cavity is communicated with the strong convection cavity through a top cooling hole;
the strong convection cavity is communicated with the central cooling cavity through a gap, the central cooling cavity is communicated with the oil return groove through a through hole, and the oil return groove is communicated with the oil return channel through an oil return hole.
Further, the axis of the top cooling hole is perpendicular to the top wall of the central cooling cavity.
Further, the side cooling holes and the cooling blind holes are located on the same axis.
Further, the axis of the side cooling bores is offset relative to the axis of the cooling blind bores, the axis of the side cooling bores being directed toward the piston head side wall.
Further, the axis of the side cooling bores is offset relative to the axis of the cooling blind bores, the axis of the side cooling bores being directed toward the top wall of the piston head.
Further, the center of the dispensing block is arched toward the top wall of the piston head.
Further, the distance between the top outer wall of the jet disc and the top wall of the central cooling cavity is 15-25 mm, and the gap is 5-10 mm.
Further, the aperture of the side cooling hole is 2-5 mm, and the aperture of the top cooling hole is 2-5 mm.
Furthermore, one end of the oil return pipe, which is close to the distribution block, is a horn mouth, and an inner hole of one end of the piston rod, which is close to the distribution block, is horn-shaped.
Further, the through hole is a kidney-shaped hole, and the cross section shape of the oil return groove is the same as that of the through hole.
The invention has the beneficial effects that:
compared with the prior art, the low-speed two-stroke engine piston provided by the invention has the advantages that the distribution oil cavity is arranged in the central cooling cavity of the piston head through the combined structure of the injection disk and the distribution block, the side/top cooling holes communicated with the distribution oil cavity are formed in the injection disk, injection cooling can be realized without installing a spray pipe, the positions, angles and the number of the side/top cooling holes arranged on the injection disk are not limited by space dimensions, the low-speed two-stroke engine piston can be arranged according to actual cooling requirements, the structure is simpler, the cooling mode is more flexible, the number of parts is effectively reduced, and the manufacturing difficulty of the piston is reduced;
after cooling oil enters the distribution oil cavity, a part of cooling oil impacts a cooling blind hole on the piston head along a side cooling hole, heat exchange is enhanced on the side surface and the top edge of the piston through free jet cooling, and the other part of cooling oil enters a strong convection cavity along the top cooling hole, impacts the wall surface of the central cooling cavity, is limited by the top wall of the central cooling cavity and the top wall of the jet disc, continuously collides, rebounds and re-collides between the two wall surfaces, and simultaneously is mutually coupled with cooling liquid in the strong convection cavity to form extremely strong turbulent flow, and heat exchange on the top surface of the piston is enhanced through limited submerged jet.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions of the prior art, the drawings that are needed in the embodiments or the description of the prior art will be briefly described below, it will be obvious that the drawings in the following description are some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort to a person skilled in the art.
FIG. 1 is a front elevational view in cross-section of the entirety of example 1 of a low speed two-stroke engine piston of the present disclosure;
FIG. 2 is a side elevational view in cross section of the entirety of example 1 of a low speed two-stroke engine piston of the present disclosure;
FIG. 3 is a top view cross-section of the entirety of example 1 of a low speed two-stroke engine piston of the present disclosure;
FIG. 4 is a schematic illustration of the structure of the injection disk of example 1 of a low speed two-stroke engine piston of the present disclosure;
FIG. 5 is a first diagram of the cooling oil flow path of example 1 of a low speed two-stroke engine piston in accordance with the present disclosure;
FIG. 6 is a second diagram of the cooling oil flow path of example 1 of a low speed two-stroke engine piston in accordance with the present disclosure;
FIG. 7 is a schematic diagram of injection cooling of example 1 of a low speed two-stroke engine piston in accordance with the present disclosure;
FIG. 8 is a schematic diagram of injection cooling of example 2 of a low speed two-stroke engine piston in accordance with the present disclosure;
FIG. 9 is a schematic diagram of injection cooling of example 3 of a low speed two-stroke engine piston in accordance with the present disclosure;
fig. 10 is an enlarged partial cross-sectional view of example 4 of a low speed two-stroke engine piston of the present disclosure.
In the figure: 1. a piston head; 11. a central cooling chamber; 12. cooling the blind hole;
2. a piston skirt;
3. a piston rod; 31. an oil inlet passage;
4. a distribution block; 41. an oil inlet hole; 42. an oil return groove; 43. an oil return hole; 44. distributing an oil cavity;
5. a jet disk; 51. a through hole; 52. a side cooling hole; 53. a top cooling hole; 54. a strong convection chamber;
6. a bolt;
7. an oil return pipe; 71. and an oil return passage.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments of the present invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Example 1
The embodiment provides a low-speed two-stroke engine piston, which comprises a piston head 1 arranged at the top of a piston rod 3, a piston skirt 2 arranged around the piston rod 3 and closely connected with the piston head 1, a distribution block 4, an injection disk 5 and an oil return pipe 7, as shown in fig. 1 and 2;
the piston head 1 is internally provided with a central cooling cavity 11 and a cooling blind hole 12 obliquely arranged at the transition part of the top wall and the side wall of the interior of the piston head 1, and the central cooling cavity 11 is communicated with the cooling blind hole 12 (in the embodiment, the cooling blind hole 12 is a flat bottom blind hole);
the oil return pipe 7 is arranged inside the piston rod 3, an oil return channel 71 is arranged in the oil return pipe 7, and an oil inlet channel 31 is formed between the oil return pipe 7 and the piston rod 3;
the distribution block 4 is arranged at one end of the oil return pipe 7 and is fixedly connected with the piston rod 3, and as shown in fig. 3, an oil inlet hole 41, an oil return groove 42 and an oil return hole 43 are arranged on the distribution block 4;
as shown in fig. 4, the injection disk 5 is provided with a through hole 51, a side cooling hole 52 and a top cooling hole 53, the injection disk 5 is fixedly connected with the distribution block 4, a strong convection cavity 54 is formed between the top wall of the injection disk 5 and the top wall of the central cooling cavity 11, and a distribution oil cavity 44 is formed between the injection disk 5 and the distribution block 4;
a gap is reserved between the transition part of the top wall and the side wall of the interior of the piston head 1 and the transition part of the top wall and the side wall of the jet disc 5;
the oil inlet channel 31 is communicated with the distribution oil cavity 44 through an oil inlet hole 41, the distribution oil cavity 44 is communicated with the central cooling cavity 11 through a side cooling hole 52 with the axis facing the bottom of the cooling blind hole 12, and the distribution oil cavity 44 is communicated with a strong convection cavity 54 through a top cooling hole 53;
the strong convection chamber 54 is communicated with the central cooling chamber 11 through a gap, the central cooling chamber 11 is communicated with the oil return groove 42 through a through hole 51, and the oil return groove 42 is communicated with the oil return passage 71 through an oil return hole 43.
Compared with the prior art, the low-speed two-stroke engine piston provided by the invention has the advantages that the distribution oil cavity 44 is arranged in the central cooling cavity 11 of the piston head 1 through the combined structure of the injection disk 5 and the distribution block 4, the injection disk 5 is provided with the side cooling holes 52 and the top cooling holes 53 which are communicated with the distribution oil cavity 44, injection cooling can be realized without installing a spray pipe, the positions, the angles and the number of the side/top cooling holes arranged on the injection disk are not limited by space size, the piston can be arranged according to actual cooling requirements, the structure is simpler, the cooling mode is more flexible, the number of parts is effectively reduced, and the manufacturing difficulty of the piston is reduced;
in the prior art, the heat exchange effect of the oscillating cooling is greatly affected by the rotating speed, the higher the rotating speed is, the better the heat exchange effect is, for a low-speed two-stroke engine, the rotating speed is lower than 300r/min, the oscillating cooling heat exchange cannot be enhanced by increasing the rotating speed, when the piston is close to the bottom dead center, the cooling oil is accumulated at the bottom of the piston oil cavity under the action of inertia force, so that the high Wen Dingmian is separated from the cooling oil, and the effective cooling cannot be obtained, therefore, the increasing heat load requirement of the piston cannot be met by the conventional oscillating cooling;
according to the low-speed two-stroke engine piston provided by the invention, as shown in fig. 5 and 6, cooling oil enters through the oil inlet channel 31, enters the distribution oil cavity 44 through the oil inlet hole 41, and part of the cooling oil impacts the cooling blind hole 12 on the piston head 1 along the side cooling hole 52, so that the heat exchange to the side and top edges of the piston head 1 is enhanced through free injection cooling, and the piston is ensured to fully exchange heat in a region near a bottom dead center;
the other part of cooling oil enters the strong convection cavity 54 along the top cooling hole 53, impacts the wall surface of the central cooling cavity 11, is limited by the top wall of the central cooling cavity 11 and the top wall of the jet disc 5, continuously collides, rebounds and re-collides between the two wall surfaces, and is continuously coupled with the cooling oil in the strong convection cavity 54 at the same time, so that strong turbulent flow is formed in the strong convection cavity 54, and the heat exchange of the top surface of the piston is enhanced by limited submerged jet cooling;
the cooling oil after heat exchange flows out through the gap, is accumulated at the bottom of the central cooling cavity 11 under the action of gravity, and finally enters the oil return channel 71 to flow out after passing through the through hole 51, the oil return groove 42 and the oil return hole 43;
the invention effectively strengthens the cooling heat exchange of the piston through the combination of the limited submerged jet cooling and the free jet cooling, meets the high requirement of the piston of the low-speed two-stroke engine on the cooling heat exchange, can effectively avoid the faults of the engine piston caused by overhigh heat load, and ensures that the engine can safely and reliably run.
In a specific embodiment, the piston rod 3, the distribution block 4 and the injection disk are fixedly connected through bolts 6, and the oil return pipe 7 is fixedly welded with the distribution block 4.
In a specific embodiment, the axis of the side cooling hole 52 is offset relative to the axis of the cooling blind hole 12, the axis of the side cooling hole 52 being directed toward the piston head 1 side wall;
in this embodiment, as shown in fig. 7, after the cooling oil impacts the bottom of the cooling blind hole 12 through the side cooling hole 52, the cooling oil flows down along the side wall of the cooling blind hole 12 and flows from the bottom of the cooling blind hole 12 to the side of the side wall of the piston head 1 to the side of the top wall, and continuously collides in the cooling blind hole 12, so that the heat exchange between the top edge and the side of the piston head 1 can be enhanced, in this embodiment, the axis of the side cooling hole 52 points to the side wall of the piston head 1, so that the jet is directed to the position of the bottom of the cooling blind hole 12 close to the side wall of the piston head 1, and the cooling heat exchange on the side wall of the piston head 1 is better.
In a specific embodiment, the center of the distribution block 4 is arched towards the top wall of the piston head 1, so that the weight of the distribution block 4 is reduced, meanwhile, the volume of the distribution oil cavity 44 between the distribution block 4 and the injection disk 5 is reduced, cooling oil can quickly fill the distribution oil cavity 44, cooling oil can quickly pass through the distribution oil cavity 44, meanwhile, the weight of the cooling oil stored in the distribution oil cavity 44 can be reduced, the weight reduction of the piston is realized by reducing the weight of the distribution block 4 and the cooling oil stored in the distribution oil cavity 44, the inertia force of the piston is reduced, the friction between the piston and a cylinder sleeve is reduced, the load of a connecting rod group is reduced, the durability of an engine is improved, and meanwhile, the whole weight of the engine can be reduced by reducing the weight, and the economy is improved.
In practical application, the transition part of the top wall and the side wall of the distribution block 4 is provided with a chamfer, the transition part of the top wall and the side wall inside the piston head 1 is provided with a chamfer, and the transition part of the top wall and the side wall inside the injection disk 5 is provided with a chamfer so as to avoid stress concentration.
In a specific embodiment, the distance between the top outer wall of the spraying disc 5 and the top inner wall of the central cooling cavity 11 is 15-25 mm (see H1 in fig. 10), the distance between the top outer wall of the spraying disc 5 and the top inner wall of the central cooling cavity 11 is 5-10 mm (see H2 in fig. 10), and the distance H2 between the top outer wall of the spraying disc 5 and the top wall of the central cooling cavity 11 is narrowed relative to the distance H1, so that the strong convection cavity 54 can be filled with cooling oil by reducing the outflow flow of the cooling oil.
In a specific embodiment, the diameter of the side cooling holes 52 is 2-5 mm, and the diameter of the top cooling holes 53 is 2-5 mm, and the small diameter ensures that the cooling oil at the same pressure is ejected from the holes at a faster flow rate.
In a specific embodiment, the axis of the cooling blind hole 12 is offset relative to the central axis of the piston head 1, and the included angle between the axis and the central axis is 15-30 degrees, so that the depth of the cooling blind hole 12 can be ensured under the angle range without affecting the strength of the piston head 1, and a good heat exchange effect can be ensured.
In a specific embodiment, one end of the oil return pipe 7, which is close to the distribution block 4, is a bell mouth, an inner hole of one end of the piston rod 3, which is close to the distribution block 4, is in a bell shape, and the inclined angle of the bell shape can enable the back flow of the cooling oil to be smoother.
In a specific embodiment, the through hole 51 is a kidney-shaped hole, the cross section of the oil return groove 42 is the same as that of the through hole 51, and the kidney-shaped hole increases the passable area, so that the cooling oil can smoothly flow back.
In a specific embodiment, the plurality of cooling blind holes 12 are distributed on the piston head 1 in a circular array around the central axis of the piston head 1, the plurality of oil inlet holes 41, the plurality of oil return grooves 42 and the plurality of oil return holes 43 are distributed on the distribution block 4 in a circular array around the central axis of the piston head 1, and the plurality of through holes 51, the plurality of side cooling holes 52 and the plurality of top cooling holes 53 are distributed on the injection disk 5 in a circular array around the central axis of the piston head 1;
the groups of cooling oil with pressure are continuously sprayed into the central cooling cavity 11 and the strong convection cavity 54 at high speed, are limited by the top wall of the central cooling cavity 11 and the top wall of the spraying disc 5, continuously collide, rebound and re-collide between the two wall surfaces, are mutually coupled with the cooling oil in the strong convection cavity 54, generate strong turbulent flow, and greatly enhance the convection heat exchange of the top surface of the piston head 1.
In practical application, the piston head 1, the piston skirt 2 and the piston rod 3 are fixedly connected through threaded fasteners.
Example 2
The working principle and main structure of this embodiment are the same as those of embodiment 1, and the difference between this embodiment and embodiment 1 is as follows:
in embodiment 1, the axis of the side cooling hole 52 is offset with respect to the axis of the cooling blind hole 12, and the axis of the side cooling hole 52 is directed toward the piston head 1 side wall.
In this embodiment, as shown in fig. 8, the side cooling holes 52 are coaxial with the cooling blind holes 12;
in this embodiment, after the cooling oil is impacted to the bottom of the cooling blind hole 12 through the side cooling hole 52, the cooling oil flows down along the side wall of the cooling blind hole 12 and flows from the center of the bottom of the cooling blind hole 12 to the outside of the bottom of the cooling blind hole 12, and continuously collides in the cooling blind hole 12, so that heat exchange between the top and the side of the piston can be enhanced, in this embodiment, the side cooling hole 52 and the cooling blind hole 12 are on the same axis, so that the jet flow is directed to the center of the bottom of the cooling blind hole 12, and the cooling heat exchange between the side wall and the top wall of the piston head 1 is relatively uniform.
Example 3
The working principle and main structure of this embodiment are the same as those of embodiment 1, and the difference between this embodiment and embodiment 1 is as follows:
in embodiment 1, the axis of the side cooling hole 52 is offset with respect to the axis of the cooling blind hole 12, and the axis of the side cooling hole 52 is directed toward the piston head 1 side wall.
In this embodiment, as shown in FIG. 9, the axis of the side cooling hole 52 is offset relative to the axis of the blind cooling hole 12, and the axis of the side cooling hole 52 is directed toward the top wall of the piston head 1;
in this embodiment, after the cooling oil is impacted to the bottom of the cooling blind hole 12 through the side cooling hole 52, the cooling oil flows downwards along the side wall of the cooling blind hole 12 and flows from the bottom of the cooling blind hole 12 to the side close to the top wall of the piston head 1, and continuously collides in the cooling blind hole 12, so that heat exchange between the top and the side of the piston can be enhanced, in this embodiment, the axis of the side cooling hole 52 points to the top wall of the piston head 1, so that the jet flow points to the bottom of the cooling blind hole 12 close to the top wall of the piston head 1, and the cooling heat exchange on the top wall of the piston head 1 is better.
Example 4
The working principle and main structure of this embodiment are the same as those of embodiment 1, and the difference between this embodiment and embodiment 1 is as follows:
in embodiment 1, the orientation of the top cooling hole 53 is not limited.
In this embodiment, as shown in fig. 10, the axis of the top cooling hole 53 is perpendicular to the top wall of the central cooling cavity 11, so that the angle of the jet flow emitted from the top cooling hole 53 and the angle of the heat exchange surface of the top wall of the central cooling cavity 11 are 90 degrees, and the maximum heat exchange coefficient can be obtained at this time, and the heat exchange effect is the best.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and not for limiting the same; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some or all of the technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit of the invention.

Claims (10)

1. A low-speed two-stroke engine piston comprising a piston head (1) arranged at the top of a piston rod (3) and a piston skirt (2) arranged around the piston rod (3) and closely connected with the piston head (1), is characterized by further comprising a distribution block (4), an injection disc (5) and an oil return pipe (7);
a central cooling cavity (11) and a cooling blind hole (12) which is obliquely arranged at the transition part of the top wall and the side wall inside the piston head (1) are arranged in the piston head (1), and the central cooling cavity (11) is communicated with the cooling blind hole (12);
the oil return pipe (7) is arranged inside the piston rod (3), an oil return channel (71) is arranged in the oil return pipe (7), and an oil inlet channel (31) is formed between the oil return pipe (7) and the piston rod (3);
the distribution block (4) is arranged at one end of the oil return pipe (7) and is fixedly connected with the piston rod (3), and the distribution block (4) is provided with an oil inlet hole (41), an oil return groove (42) and an oil return hole (43);
the spray disc (5) is provided with a through hole (51), a side cooling hole (52) and a top cooling hole (53), the spray disc (5) is fixedly connected with the distribution block (4), a strong convection cavity (54) is formed between the top wall of the spray disc (5) and the top wall of the central cooling cavity (11), and a distribution oil cavity (44) is formed between the spray disc (5) and the distribution block (4);
gaps are reserved between the transition part of the top wall and the side wall of the interior of the piston head (1) and the transition part of the top wall and the side wall of the jet disc (5);
the oil inlet channel (31) is communicated with the distribution oil cavity (44) through an oil inlet hole (41), the distribution oil cavity (44) is communicated with the central cooling cavity (11) through a side cooling hole (52) with the axis facing the bottom of the cooling blind hole (12), and the distribution oil cavity (44) is communicated with the strong convection cavity (54) through a top cooling hole (53);
the strong convection cavity (54) is communicated with the central cooling cavity (11) through a gap, the central cooling cavity (11) is communicated with the oil return groove (42) through a through hole (51), and the oil return groove (42) is communicated with the oil return channel (71) through an oil return hole (43).
2. A low speed two stroke engine piston according to claim 1, wherein the axis of the top cooling hole (53) is perpendicular to the top wall of the central cooling chamber (11).
3. A low speed two stroke engine piston according to claim 1, wherein the side cooling bores (52) are coaxial with the cooling blind bores (12).
4. A low speed two stroke engine piston according to claim 1, wherein the axis of the side cooling hole (52) is offset with respect to the axis of the cooling blind hole (12), the axis of the side cooling hole (52) being directed towards the piston head (1) side wall.
5. A low speed two stroke engine piston according to claim 1, wherein the axis of the side cooling hole (52) is offset with respect to the axis of the cooling blind hole (12), the axis of the side cooling hole (52) being directed towards the top wall of the piston head (1).
6. A low speed two stroke engine piston according to claim 1, wherein the centre of the distributor block (4) is arched towards the top wall of the piston head (1).
7. A low speed two stroke engine piston according to claim 1, wherein the distance between the top outer wall of the injection disc (5) and the top wall of the central cooling chamber (11) is 15-25 mm, said gap being 5-10 mm.
8. A low speed two stroke engine piston according to claim 1, wherein the side cooling holes (52) have a bore diameter of 2-5 mm and the top cooling holes (53) have a bore diameter of 2-5 mm.
9. A low-speed two-stroke engine piston according to claim 1, wherein the end of the oil return pipe (7) close to the distribution block (4) is a bell mouth, and the inner hole of the end of the piston rod (3) close to the distribution block (4) is bell-shaped.
10. A low-speed two-stroke engine piston according to claim 1, wherein the through hole (51) is a kidney-shaped hole, and the oil return groove (42) has the same cross-sectional shape as the through hole (51).
CN202310616838.2A 2023-05-29 2023-05-29 Piston of low-speed two-stroke engine Pending CN116857082A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310616838.2A CN116857082A (en) 2023-05-29 2023-05-29 Piston of low-speed two-stroke engine

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310616838.2A CN116857082A (en) 2023-05-29 2023-05-29 Piston of low-speed two-stroke engine

Publications (1)

Publication Number Publication Date
CN116857082A true CN116857082A (en) 2023-10-10

Family

ID=88217926

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310616838.2A Pending CN116857082A (en) 2023-05-29 2023-05-29 Piston of low-speed two-stroke engine

Country Status (1)

Country Link
CN (1) CN116857082A (en)

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