CN219299423U - Piston and methanol engine - Google Patents

Abstract

The utility model discloses a piston and a methanol engine, wherein a combustion chamber is concavely arranged on the top surface of the piston, the combustion chamber comprises a bottom wall and a side wall, the side wall is obliquely arranged towards the central axis of the piston and is connected with the bottom wall, a first contour line intersecting with the bottom wall along the first section of the central axis of the piston is an arc line protruding towards the top surface far away from the piston, a second contour line intersecting with the bottom wall along the second section of the central axis of the piston is a straight line, and the first section and the second section are orthogonal. According to the technical scheme, turbulent energy in the cylinder can be improved, so that the thermal efficiency of the engine is improved.

Description

Piston and methanol engine

Technical Field

The utility model relates to the technical field of engines, in particular to a piston and methanol engine.

Background

Gas engines such as natural gas, methanol heavy duty engines and the like are all developed on the basis of diesel engines. The diesel engine belongs to a compression ignition type diffusion combustion mode, and is developed in a mode of surrounding vortex air inlet to air inlet structure and flow in a cylinder of the engine, and the flow in the cylinder is also used for promoting the mixing of diesel oil and air, so that high-efficiency combustion and low pollutant emission are realized; the natural gas and the methanol have higher spontaneous combustion temperature due to the characteristic of fuel, the ignition type combustion mode of the spark plug has high requirements on the air inlet mode, the tumble ratio in the cylinder and the turbulent energy, and if the large-size flow of vortex flow exists in the gas engine, the flow speed near the spark plug is lower at the end of compression, the longitudinal flow speed is also lower, the vortex flow cannot be broken into small-size turbulence, the turbulent energy is lower easily caused, and the mixing effect of the gas and the air is influenced, so the thermal efficiency of the engine is reduced.

Disclosure of Invention

The main purpose of the utility model is to provide a piston which aims at improving turbulence energy in a cylinder so as to improve the thermal efficiency of an engine.

In order to achieve the above object, the top surface of the piston provided by the utility model is concavely provided with a combustion chamber, the combustion chamber comprises a bottom wall and a side wall, the side wall is obliquely arranged towards the central axis of the piston and is connected with the bottom wall, a first contour line intersecting with the bottom wall along a first section of the central axis of the piston is an arc line protruding towards the top surface far away from the piston, a second contour line intersecting with the bottom wall along a second section of the central axis of the piston is a straight line, and the first section and the second section are orthogonal.

Optionally, the side wall includes two first water conservancy diversion wall surfaces and two second water conservancy diversion wall surfaces, two first water conservancy diversion wall surfaces and two second water conservancy diversion wall surfaces are in turn alternately and smoothly meet along circumference, first water conservancy diversion wall surface with the diapire is smooth to meet, the second water conservancy diversion wall surface with diapire circular arc transition.

Optionally, an included angle between the first guide wall surface and the top surface of the piston is smaller than an included angle between the first guide wall surface and the top surface of the piston.

Optionally, the first guide wall surface and the second guide wall surface are in arc transition with the top surface of the piston.

Optionally, the two first guide wall surfaces are respectively opposite to the air inlet and the air outlet.

Optionally, the air inlet and the air outlet are both provided with two.

Optionally, the two first guide wall surfaces are symmetrically disposed about the second section, and the two second guide wall surfaces are symmetrically disposed about the first section.

Optionally, a maximum distance between the first contour and the top surface of the piston is equal to a distance between the second contour and the top surface of the piston.

Optionally, an edge profile of a side of the side wall remote from the bottom wall is elliptical.

The utility model also proposes a methanol engine comprising a piston as described above.

According to the technical scheme, compared with a traditional circular combustion chamber, the ship-shaped combustion chamber structure is designed, so that the combustion chamber structure is more compliant with the inlet air flow to generate tumble flow, and the inlet tumble flow is matched with the flow of the inlet tumble flow to further promote and strengthen the inlet tumble flow, so that air and gas fuel in a cylinder are further mixed, turbulence energy and turbulence intensity in the cylinder are effectively improved, flame propagation speed is improved, the possibility of knocking is reduced, and therefore, the thermal efficiency, the use reliability and the economy of the engine are improved.

Drawings

In order to more clearly illustrate the embodiments of the present utility model or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are only some embodiments of the present utility model, and other drawings may be obtained according to the structures shown in these drawings without inventive effort for a person skilled in the art.

FIG. 1 is a schematic view of an embodiment of a piston according to the present utility model;

FIG. 2 is a schematic view of the piston of FIG. 1 taken in a first cross-section;

fig. 3 is a schematic structural view of the piston of fig. 1 after being cut in a second section.

Reference numerals illustrate:

the achievement of the objects, functional features and advantages of the present utility model will be further described with reference to the accompanying drawings, in conjunction with the embodiments.

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the utility model without making any inventive effort, are intended to be within the scope of the utility model.

In the present utility model, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

It should be noted that, if directional indications (such as up, down, left, right, front, and rear … …) are included in the embodiments of the present utility model, the directional indications are merely used to explain the relative positional relationship, movement conditions, etc. between the components in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indications are correspondingly changed.

In addition, if there is a description of "first", "second", etc. in the embodiments of the present utility model, the description of "first", "second", etc. is for descriptive purposes only and is not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the meaning of "and/or" as it appears throughout is meant to include three side-by-side schemes, for example, "a and/or B", including a scheme, or B scheme, or a scheme that is satisfied by both a and B. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be considered to be absent and not within the scope of protection claimed in the present utility model.

The utility model provides a piston 10, which is applied to a gas engine, such as a natural gas engine and a methanol engine.

Referring to fig. 1 to 3, in the embodiment of the present utility model, the top surface 13 of the piston 10 is concavely provided with a combustion chamber 20, the combustion chamber 20 includes a bottom wall 21 and a side wall 22, the side wall 22 is obliquely disposed toward the central axis of the piston 10 and is connected with the bottom wall 21, a first contour 23 intersecting the first section 11 and the bottom wall 21 along the central axis of the piston 10 is an arc protruding away from the top surface 13 of the piston 10, a second contour 24 intersecting the second section 12 and the bottom wall 21 along the central axis of the piston 10 is a straight line, the first section 11 and the second section 12 are orthogonal, wherein the top surface 13 of the piston 10 is disposed facing the cylinder cover of the engine, and an air flow flows in a space between the cylinder cover and the top surface 13 of the piston 10, so that compared with the conventional circular combustion chamber 20, the structure of the combustion chamber 20 can be more conformed to the air flow of the intake air flow to generate a tumble, thereby further promote and strengthen the air flow in the cylinder, further mix the air and the gas fuel in the cylinder with the air flow, the turbulent flow and the turbulent flow strength in the cylinder are effectively promoted, the propagation speed of the engine is improved, the thermal turbulent flow is improved, and the flame propagation speed is reduced, and the thermal efficiency and the flame efficiency is reduced.

Because the side wall 22 is connected with the bottom wall 21 and is obliquely arranged towards the central axis of the piston 10, gas entering the combustion chamber 20 generates rolling flow motion under the guiding action of the side wall 22, and the momentum of the rolling flow is less attenuated in the compression process, so that the momentum can be stored to the end stage of the compression stroke, when the piston 10 is close to the top dead center, the large-scale strong rolling flow is broken into a plurality of small-scale rolling flows, the turbulence intensity and the turbulence energy of the end stage of compression are increased, the flame propagation speed is greatly improved, the knocking tendency is reduced, the thermal efficiency of the engine is improved, and the economy and the use reliability are improved.

The bottom wall 21 is in an arc line protruding towards the top surface 13 far away from the piston 10 at the first contour line 23 of the first section 11, and is in a straight line at the second contour line 24 of the second section 12, it can be understood that the arc structure of the bottom wall 21 further conforms to the air inlet tumble flow to promote the further mixing of the gas fuel and the air, and the second contour line 24 of the bottom wall 21 is in a straight line at the second section 12 because the second section 12 is orthogonal to the first section 11, namely, is perpendicular to each other, so that the area of the combustion chamber 20 on the second section 12 is effectively increased, the tumble flow range in the combustion chamber 20 is further increased, the tumble flow ratio is improved, and the mixing of the air and the gas fuel is more promoted, so that on one hand, the ignition of the spark plug is effectively promoted, and the risk of fire is reduced; on the other hand, the air flow movement intensity and turbulence energy in the combustion chamber 20 after the compression stroke are improved, the flame propagation speed is greatly improved, the knocking tendency is reduced, the heat efficiency of the engine is improved, and the economy and the use reliability are improved.

According to the technical scheme, compared with the traditional circular combustion chamber 20, the ship-shaped combustion chamber 20 is designed, so that the structure of the combustion chamber 20 is more compliant with the inlet airflow to generate tumble, and the inlet tumble is matched with the flow of the inlet tumble to further promote and strengthen the inlet tumble, so that air and gas fuel in a cylinder are further mixed, turbulence energy and turbulence intensity in the cylinder are effectively improved, flame propagation speed is improved, the possibility of knocking is reduced, and therefore, the thermal efficiency, the use reliability and the economy of the engine are improved.

Optionally, in an embodiment, the side wall 22 includes two first guide wall surfaces 221 and two second guide wall surfaces 222, where the two first guide wall surfaces 221 and the two second guide wall surfaces 222 are sequentially and alternately and smoothly connected along the circumferential direction, the first guide wall surfaces 221 are smoothly connected with the bottom wall 21, and the second guide wall surfaces 222 are in arc transition with the bottom wall 21, that is, the first guide wall surfaces 221 and the second guide wall surfaces 222 are alternately arranged along the circumferential direction of the piston 10, the adjacently arranged first guide wall surfaces 221 and the second guide wall surfaces 222 are smoothly connected, and meanwhile, the connection part between the side wall 22 and the bottom wall 21 is smoothly connected, so that structural abrupt change of the combustion chamber 20 can be effectively reduced, and a tumble can be smoothly formed in the process that gas is guided by the side wall 22 and flows to the bottom wall 21 of the combustion chamber 20, so that the flame propagation speed of the gas flow in the combustion chamber 20 is accelerated, and the thermal efficiency of the engine is improved. The radius of the circular arc formed by the circular arc transition between the second guide wall surface 222 and the bottom wall 21 may be set according to the inclination of the second guide wall surface 222.

Optionally, in an embodiment, the included angle between the first guide wall 221 and the top surface 13 of the piston 10 is smaller than the included angle between the first guide wall 221 and the top surface 13 of the piston 10, that is, the first guide wall 221 is relatively gentle, so as to be beneficial to guiding the airflow flowing into the combustion chamber 20 to flow toward the bottom wall 21, the second guide wall 222 is relatively steep, so as to be beneficial to rolling the airflow flowing into the combustion chamber 20 along the second guide wall 222 and increasing the rolling range in the combustion chamber 20, thereby increasing the rolling ratio, matching with the design that the first contour line 23 of the bottom wall 21 in the first section 11 is in an arc protruding toward the top surface 13 far from the piston 10, and the second contour line 24 in the second section 12 is in a straight line, so that the airflow is greatly promoted to form a rolling flow better, and the gaseous fuel and the air are better mixed, thus being capable of meeting the flow requirement in the cylinder, having a higher rolling ratio and turbulent energy requirement, further accelerating the flame propagation speed of the airflow in the combustion chamber 20, and improving the thermal efficiency of the engine.

Specifically, the included angle between the first guide wall surface 221 and the top surface 13 of the piston 10 may be a1, a1 may be greater than or equal to 33 ° and less than or equal to 34 °, where a specific value of a1 may be 33.1 °, 33.2 °, 33.3 °, 33.4 °, 33.5 °, 33.6 °, 33.7 °, 33.8 °, 33.9 °, 34 °. The included angle between the first diversion wall surface 221 and the top surface 13 of the piston 10 is a2, a2 may be greater than or equal to 49.5 ° and less than or equal to 50.5 °, wherein a specific value of a2 may be 49.5 °, 49.6 °, 49.7 °, 49.8 °, 49.9 °, 50 °, 50.1 °, 50.2 °, 50.3 °, 50.4 °, 50.5 °.

Optionally, in an embodiment, the first guide wall 221 and the second guide wall 222 are in arc transition with the top surface 13 of the piston 10, so that the connection between the side wall 22 of the combustion chamber 20 and the top surface 13 of the piston 10 is configured to form an arc structure, which is beneficial to further increasing the possibility of forming a tumble when the airflow enters the combustion chamber 20; at the same time, the abnormal local temperature of the piston 10 caused by the over sharp joint can be reliably avoided. Wherein, the radius of the circular arc is R, and R can be set according to actual needs.

Optionally, in an embodiment, the two first guide wall surfaces 221 are disposed opposite to the air inlet and the air outlet, respectively, and it is understood that the air flows in from the air inlet and flows toward the bottom wall 21 under the guiding action of the first guide wall surfaces 221, and meanwhile, since the two first guide wall surfaces 221 are disposed obliquely toward the central axis of the piston 10, they are respectively disposed on opposite sides of the central axis of the piston 10 and smoothly connected to the bottom wall 21, so that the air flowing toward the bottom wall 21 can roll along the first guide wall surfaces 221, the bottom wall 21 and the first guide wall surfaces 221 to form a rolling flow.

Optionally, in an embodiment, both the air inlet and the air outlet are provided.

Referring to fig. 1 to 3, in an embodiment, two first guide wall surfaces 221 are symmetrically disposed about the second section 12, and two second guide wall surfaces 222 are symmetrically disposed about the first section 11, and it is understood that two air inlets and two air outlets are symmetrically disposed about the second section 12. The two first diversion lines of the two first diversion wall surfaces 221 on the first section 11 are symmetrically arranged about the second section 12 and are respectively connected to two ends of the first contour line 23, wherein the first diversion lines and the first contour line 23 are in smooth transition, the whole is in an arc-shaped structure, and the lines are relatively slow, so that the air flow can flow to the bottom wall 21 or flow out of the bottom wall 21 by being matched with the air inlet conveniently; the two second diversion walls 222 on the second section 12 are symmetrically arranged about the first section 11 and are respectively connected to two ends of the second contour line 24, wherein the second diversion walls and the second contour line 24 are in arc transition, and the whole is in a basin-shaped structure, so that the tumble range of the combustion chamber 20 is conveniently enlarged, the efficient mixing of gas fuel and air is facilitated, the turbulence intensity and turbulence energy are enhanced, the flame propagation speed is increased, and the heat efficiency of the engine is improved. In addition, the symmetrical arrangement of the two first guide wall surfaces 221 and the symmetrical arrangement of the two second guide wall surfaces 222 can further ensure the relative uniformity of the air flow in the combustion chamber 20.

Optionally, in an embodiment, the maximum distance between the first contour line 23 and the top surface 13 of the piston 10 is equal to the distance between the second contour line 24 and the top surface 13 of the piston 10, so that the occurrence of abrupt changes in the structure of the bottom wall 21 to disrupt the flow path of the air flow can be effectively avoided, thereby facilitating the formation of the tumble flow.

Optionally, in an embodiment, the edge profile of the side wall 22 away from the bottom wall 21 is elliptical, wherein the maximum distance between the two first guiding wall surfaces 221 is greater than the maximum distance between the two second guiding wall surfaces 222, and the first guiding wall surfaces 221 are disposed in a gentle slope on the whole, and have a longer guiding length, so as to be beneficial to follow the airflow and generate the tumble flow.

The utility model also provides a methanol engine, which comprises a piston 10, wherein the specific structure of the piston 10 refers to the embodiment, and as the methanol engine adopts all the technical schemes of all the embodiments, the methanol engine has at least all the beneficial effects brought by the technical schemes of the embodiments, and the description is omitted herein.

The foregoing description is only of the optional embodiments of the present utility model, and is not intended to limit the scope of the utility model, and all the equivalent structural changes made by the description of the present utility model and the accompanying drawings or the direct/indirect application in other related technical fields are included in the scope of the utility model.

Claims (10)

1. The utility model provides a piston, its characterized in that, the top surface of piston is concave to be equipped with the combustion chamber, the combustion chamber includes diapire and lateral wall, the lateral wall orientation the axis slope setting of piston, and with the diapire is connected, along the first cross-section of axis of piston with the crossing first contour line of diapire is the arc of keeping away from the protruding top surface of piston, along the second cross-section of axis of piston with the crossing second contour line of diapire is the straight line, first cross-section with the second cross-section quadrature.

2. The piston of claim 1 wherein said side wall includes two first guide wall surfaces and two second guide wall surfaces, said two first guide wall surfaces and said two second guide wall surfaces alternating in sequence and smoothly meeting in a circumferential direction, said first guide wall surfaces smoothly meeting said bottom wall, said second guide wall surfaces transitioning with said bottom wall arcuate.

3. The piston of claim 2 wherein an angle between the first deflector wall and a top surface of the piston is less than an angle between the first deflector wall and a top surface of the piston.

4. The piston of claim 2 wherein said first guide wall surface and said second guide wall surface each transition with an arc of a top surface of said piston.

5. The piston of claim 2 wherein two of said first guide walls are disposed opposite said inlet and said outlet, respectively.

6. The piston of claim 5 wherein said intake port and said exhaust port are each provided with two.

7. The piston of any one of claims 2 to 6 wherein two of said first guide wall surfaces are symmetrically disposed about said second cross-section and two of said second guide wall surfaces are symmetrically disposed about said first cross-section.

8. The piston of claim 1 wherein a maximum distance between the first contour line and a top surface of the piston is equal to a distance between the second contour line and the top surface of the piston.

9. The piston of claim 1 wherein the side wall has an oval edge profile on a side remote from said bottom wall.

10. A methanol engine comprising a piston as claimed in any one of claims 1 to 9.

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