A gas engine combustion chamber suitable for equivalence ratio combustion

Abstract

The present invention relates to a gas engine combustion chamber suitable for equivalent ratio combustion, comprising: a piston; a combustion chamber, which is arranged in the piston, an opening is arranged at the top of the combustion chamber, an intake passage and an exhaust passage are arranged above the opening, and the axis of the combustion chamber deviates from the intake passage by a first preset distance relative to the axis of the piston. By designing the combustion chamber to be offset relative to the piston in the direction away from the intake passage, the gas entering from the intake passage can be evenly distributed in the combustion chamber, the gas flow velocity and turbulence size along the direction perpendicular to the axis of the combustion chamber are relatively consistent, the flow field distribution in the cylinder is improved, the flame is more evenly distributed in the combustion chamber, the combustion cycle changes caused by uneven combustion are reduced, and the knock tendency is reduced.

Description

Technical Field

[0001] The present invention relates to the field of engines, and in particular to a gas engine combustion chamber suitable for equivalence ratio combustion. Background Art

[0002] Currently, to reduce development cycles and costs, gas engines are generally developed based on diesel engines. Due to the development of high-pressure common rail technology, diesel engines have mostly straight airways with relatively low turbulence. Ultra-high injection pressures are used to promote fuel-gas mixing, resulting in efficient and clean combustion. Natural gas has two combustion modes: single-fuel ignition and dual-fuel compression ignition. The most typical dual-fuel compression ignition mode is HPDI combustion, which features a fuel injection device located in the center of the combustion chamber. Diesel fuel is used for ignition, and then the combustible gas is injected simultaneously with combustion. Single-fuel ignition engines typically utilize premixed combustion. Natural gas, air, and exhaust gases are premixed and enter the cylinder through the intake manifold. A spark plug is located in the center of the combustion chamber, initiating the combustion process. Because the gases are premixed before entering the cylinder, the flame propagation rate depends on the amount of turbulent kinetic energy within the cylinder. The combustion chamber shape significantly influences the amount and distribution of turbulent kinetic energy.

[0003] Gas engine piston combustion chambers are primarily shallow basin-shaped. These chambers have a uniform height and a certain squish area, but the squish flow effect is poor and the flame propagation is slow. To improve the combustion process within the cylinder, a high-turbulence gas engine combustion chamber has been proposed in the related art. By modifying the throat opening and bottom surface shape, either the throat opening is designed to be elliptical or the bottom surface is designed to be elliptical, increasing the turbulence intensity within the cylinder and accelerating combustion. However, because the intake duct is offset to one side of the combustion chamber, the gas flow velocity and turbulence level along a plane perpendicular to the combustion chamber axis are inconsistent. Gas entering through the intake duct is concentrated within the combustion chamber on the side closest to the exhaust duct. The turbulent kinetic energy near the exhaust duct is greater, causing the flame core to shift toward the exhaust side during propagation. This results in significant flame asymmetry within the combustion chamber, with the majority of the flame distributed within the combustion chamber space on the exhaust side. The airflow within the intake-side combustion chamber space is not fully utilized, resulting in low thermal efficiency, high combustion cycle variability, and a greater tendency to knock. Summary of the Invention

[0004] An embodiment of the present invention provides a gas engine combustion chamber suitable for equivalence ratio combustion to solve the problems in related technologies in which most of the flame is distributed in the combustion chamber space on the exhaust side, the airflow in the combustion chamber space on the intake side cannot be fully utilized, the thermal efficiency is low, the combustion cycle fluctuation is high, and the knock tendency increases.

[0005] In a first aspect, a gas engine combustion chamber suitable for equivalence ratio combustion is provided, which includes: a piston; a combustion chamber, which is arranged in the piston, an opening is provided at the top of the combustion chamber, an intake duct and an exhaust duct are provided above the opening, and the axis of the combustion chamber deviates from the axis of the piston by a first preset distance in a direction away from the intake duct.

[0006] In some embodiments, a spark plug is provided above the combustion chamber, and an axis of the spark plug deviates from an axis of the piston by a second preset distance in a direction close to the intake passage.

[0007] In some embodiments, a ratio of an offset distance between an axis of the spark plug and an axis of the piston to a diameter of the piston is 0.01 to 0.02.

[0008] In some embodiments, a ratio of an offset distance between an axis of the combustion chamber and an axis of the piston to a diameter of the piston is 0.02 to 0.04.

[0009] In some embodiments, an upper squeeze flow zone is provided at the upper end of the inner wall of the combustion chamber, the portion of the upper squeeze flow zone close to the opening protrudes inward, and the portion away from the opening protrudes outward, and the ratio of the diameter of the lower end of the upper squeeze flow zone to the diameter of the piston is 0.51 to 0.53.

[0010] In some embodiments, a throat is provided on the inner wall of the combustion chamber, the upper end of the throat is connected to the lower end of the upper squeezing area, the throat is in the shape of an arc convex inward, and the ratio of the distance from the center of the throat to the top surface of the combustion chamber to the depth of the combustion chamber is 0.1 to 0.12.

[0011] In some embodiments, a central squeeze flow zone is provided in the middle of the inner wall of the combustion chamber, the upper end of the central squeeze flow zone is connected to the lower end of the throat, the central squeeze flow zone is conical, and the cross-sectional size gradually expands from top to bottom, and the angle between the cross-section of the wall of the central squeeze flow zone and the axis of the piston is 25° to 28°.

[0012] In some embodiments, a pit is provided at the lower end of the inner wall of the combustion chamber, the upper end of the pit is connected to the lower end of the middle squeezing area, the pit is in the shape of an arc convex outward, and the ratio of the radius of the pit to the diameter of the piston is 0.07 to 0.08.

[0013] In some embodiments, a spherical cap bottom surface is provided at the bottom of the combustion chamber, and the spherical cap bottom surface is in an inwardly convex arc shape, and the ratio of the diameter of the spherical cap bottom surface to the diameter of the piston is 1.7 to 1.8.

[0014] In some embodiments, the axis of the spark plug is parallel to the axis of the piston, and the axis of the combustion chamber is parallel to the axis of the piston.

[0015] The beneficial effects brought about by the technical solution provided by the present invention include:

[0016] An embodiment of the present invention provides a gas engine combustion chamber suitable for equivalence ratio combustion. By offsetting the combustion chamber relative to the piston in a direction away from the intake duct, the gas entering from the intake duct can be evenly distributed in the combustion chamber, and the gas flow velocity and turbulence size along the axis perpendicular to the combustion chamber are relatively consistent, thereby improving the flow field distribution in the cylinder, making the flame more evenly distributed in the combustion chamber, reducing the combustion cycle changes caused by uneven combustion, and reducing the tendency of knock. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A schematic diagram of the overall structure of a gas engine combustion chamber suitable for equivalence ratio combustion provided by an embodiment of the present invention;

[0019] Figure 2 A schematic diagram of the partial structure of a combustion chamber of a gas engine suitable for equivalence ratio combustion provided by an embodiment of the present invention;

[0020] Figure 3 A schematic diagram of the three-dimensional structure of a combustion chamber of a gas engine suitable for equivalence ratio combustion provided by an embodiment of the present invention;

[0021] Figure 4 A schematic top view of a combustion chamber of a gas engine suitable for equivalence ratio combustion provided in an embodiment of the present invention.

[0022] Numbers in the figure:

[0023] 1. Piston; 2. Combustion chamber; 21. Opening; 22. Upper squeeze area; 23. Throat; 24. Middle squeeze area; 25. Concave groove; 26. Bottom of the spherical crown; 3. Intake duct; 4. Exhaust duct; 5. Spark plug. DETAILED DESCRIPTION

[0024] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0025] In related technologies, since the intake duct is biased toward one side of the combustion chamber, the gas flow velocity and turbulence size along the axis perpendicular to the axis are inconsistent. The turbulent kinetic energy is larger on the side close to the exhaust duct, causing the fire core to shift toward the exhaust side when propagating. The flame in the combustion chamber shows obvious asymmetry, and most of the flame is distributed in the combustion chamber space on the exhaust side. The airflow in the combustion chamber space on the intake side cannot be fully utilized, resulting in low thermal efficiency, high combustion cycle fluctuations, and a greater tendency to detonation.

[0026] An embodiment of the present invention provides a gas engine combustion chamber suitable for equivalence ratio combustion, which can solve the problems in related technologies in which most of the flame is distributed in the combustion chamber space on the exhaust side, the airflow in the combustion chamber space on the intake side cannot be fully utilized, the thermal efficiency is low, the combustion cycle fluctuation is high, and the knock tendency increases.

[0027] See also Figure 1 As shown, a gas engine combustion chamber suitable for equivalence ratio combustion provided in an embodiment of the present invention may include: a piston 1; a combustion chamber 2, which is arranged in the piston 1, and an opening 21 is provided at the top of the combustion chamber 2, and an intake duct 3 and an exhaust duct 4 are provided above the opening 21, and the axis of the combustion chamber 2 deviates from the axis of the piston 1 by a first preset distance in the direction away from the intake duct 3.

[0028] In this embodiment, the piston 1 is cylindrical, and the combustion chamber 2 is formed by being recessed from the surface of the piston 1. The intake passage 3 is provided on one side of the combustion chamber 2 and is communicated with the interior of the combustion chamber 2. The exhaust passage 4 is provided on the other side of the combustion chamber 2 and is communicated with the interior of the combustion chamber 2. The gas enters the combustion chamber 2 from the intake passage 3. Since the combustion chamber 2 is offset relative to the piston 1 in the direction away from the intake passage 3, that is, compared with the traditional design in which the axis of the combustion chamber 2 coincides with the axis of the piston 1, the area in which the intake port of the intake passage 3 coincides with the opening 21 of the combustion chamber 2 is larger, the axis of the combustion chamber 2 in this embodiment is closer to the piston 1 than the axis of the piston 1. 1 deviates from the axis, which reduces the overlapping area between the air inlet of the intake duct 3 and the opening 21 of the combustion chamber 2. The gas entering through the intake duct 3 can be evenly distributed in the combustion chamber 2. The gas flow velocity and turbulence size along the axis perpendicular to the combustion chamber 2 are relatively consistent, which improves the flow field distribution in the cylinder. The turbulent kinetic energy on the side of the combustion chamber 2 close to the exhaust duct 4 is not much different from the turbulent kinetic energy on the side close to the intake duct 3. The fire core propagates more evenly, the flame in the combustion chamber 2 is more symmetrical, and the flame is evenly distributed in the space of the combustion chamber 2. The airflow in the combustion chamber 2 can be fully utilized, the thermal efficiency is high, the combustion cycle fluctuation is low, and the knock tendency is reduced.

[0029] See also Figure 1 、 Figure 3 and Figure 4 As shown, in some embodiments, a spark plug 5 is provided above the combustion chamber 2 , and the axis of the spark plug 5 can deviate from the axis of the piston 1 by a second preset distance in a direction close to the intake passage 3 .

[0030] In this embodiment, the function of the spark plug 5 is to discharge pulsed high voltage electricity sent from the high-voltage wire (the nozzle wire), break down the air between the two electrodes of the spark plug 5, and generate an electric spark to ignite the mixed gas in the combustion chamber 2. The cathode of the spark plug 5 extends into the combustion chamber 2. By offsetting the combustion chamber 2 and the spark plug 5 in opposite directions relative to the axis of the piston 1, that is, the spark plug 5 is offset relative to the piston 1 toward the intake duct 3, and the combustion chamber 2 is offset relative to the piston 1 away from the intake duct 3, the flow field distribution in the cylinder is improved, and the turbulent kinetic energy is evenly distributed throughout the combustion chamber 2, thereby optimizing the combustion process, shortening the combustion duration, and improving gas economy. At the same time, the simultaneous offset design of the spark plug 5 and the combustion chamber 2 ensures engine reliability while making the flame more evenly distributed in the combustion chamber 2, reducing the combustion cycle fluctuations caused by uneven combustion, and reducing the tendency of knock. This design can reduce the knock index KP-PK value from 3 to between 1.5 and 2, thereby reducing the occurrence of knock. Therefore, this embodiment can significantly improve the anti-knock performance of the engine and reduce the tendency of knock.

[0031] In some optional embodiments, the spark plug 5 may not be offset and the combustion chamber 2 may be offset by a larger distance, or the combustion chamber 2 may not be offset and the spark plug 5 may be offset by a larger distance, or both the combustion chamber 2 and the spark plug 5 may be offset, and the above-mentioned effects may be achieved.

[0032] See also Figure 1 As shown, in some embodiments, the ratio of the offset distance between the axis of the spark plug 5 and the axis of the piston 1 to the diameter of the piston 1 is 0.01 to 0.02. In this embodiment, by making the offset distance of the spark plug 5 relative to the piston 1 smaller, the flow field distribution in the cylinder can be better improved while ensuring the reliability of the engine body, making the turbulent kinetic energy more evenly distributed in the entire combustion chamber 2, better optimizing the combustion process, shortening the combustion duration, and improving gas economy; making the flame more evenly distributed in the combustion chamber 2, reducing the combustion cycle changes caused by uneven combustion, reducing the tendency of knock, and significantly improving the engine's anti-knock performance. In other embodiments, the ratio of the offset distance between the axis of the spark plug 5 and the axis of the piston 1 to the diameter of the piston 1 can also be set to other data according to actual conditions.

[0033] See also Figure 1 As shown, in some embodiments, the ratio of the offset distance between the axis of the combustion chamber 2 and the axis of the piston 1 to the diameter of the piston 1 is 0.02 to 0.04. In this embodiment, by reducing the offset distance of the combustion chamber 2 relative to the piston 1, the flow field distribution in the cylinder can be improved while ensuring the reliability of the engine body, making the turbulent kinetic energy more evenly distributed throughout the entire combustion chamber 2, better optimizing the combustion process, shortening the combustion duration, and improving gas economy. The flame is more evenly distributed in the combustion chamber 2, reducing the combustion cycle fluctuations caused by uneven combustion, reducing the tendency of knock, and significantly improving the engine's anti-knock performance. In other embodiments, the ratio of the offset distance between the axis of the combustion chamber 2 and the axis of the piston 1 to the diameter of the piston 1 can also be set to other values ​​according to actual conditions.

[0034] In some embodiments, the top surface of the piston 1 to the bottom surface of the combustion chamber 2 is formed by connecting the upper squeeze flow area 22, the throat 23, the middle squeeze flow area 24 and the lower squeeze flow area in sequence. The lower squeeze flow area is formed by connecting the pit 25 and the bottom surface of the spherical cap 26. By improving the shape of various parts in the combustion chamber 2, the turbulence intensity in the cylinder is increased and the combustion is accelerated.

[0035] See also Figure 2 As shown, in some embodiments, an upper squeeze flow area 22 is provided at the upper end of the inner wall of the combustion chamber 2, the portion of the upper squeeze flow area 22 close to the opening 21 protrudes inward, and the portion away from the opening 21 protrudes outward, and the ratio of the lower end diameter of the upper squeeze flow area 22 to the diameter of the piston 1 is 0.51 to 0.53.

[0036] In this embodiment, the upper squeezing area 22 of the combustion chamber 2 is located at the opening 21 at the top of the combustion chamber 2 at the top of the piston 1, and is formed by two arcs of equal diameter connected tangentially. Specifically, the upper edge of the upper arc of the upper squeezing area 22 is connected to the edge of the opening 21 of the combustion chamber 2, and the lower edge is connected to the lower arc. The upper edge of the lower arc is connected to the lower edge of the upper arc, and the lower edge is connected to the upper edge of the throat 23; the ratio of the lower end surface diameter of the upper squeezing area 22 of the combustion chamber 2 to the diameter of the piston 1 (cylinder) is 0.51 to 0.53. By adopting a smaller diameter ratio, a larger squeezing velocity is obtained near the compression top dead center, and a stronger squeezing motion is formed inside the combustion chamber 2, which increases the turbulent kinetic energy around the spark plug 5 at the ignition moment, and the flame propagation speed is fast, which is conducive to the formation of the fire core and the development of the flame in the early stage of combustion, and can effectively increase the combustion reaction rate and improve the thermal efficiency of the gas engine.

[0037] Furthermore, the upper squeeze flow area 22 has two parts, the part close to the opening 21 protrudes inward, and the part away from the opening 21 protrudes outward, which is conducive to forming a stronger squeeze flow movement. In other embodiments, the upper squeeze flow area 22 can also be a whole that only protrudes inward. The upper squeeze flow area 22 can also be designed into other shapes, for example, it can be conical or stepped; the ratio of the lower end diameter of the upper squeeze flow area 22 to the diameter of the piston 1 is 0.51~0.53. In other embodiments, the ratio of the diameter of the upper squeeze flow area 22 to the diameter of the piston 1 can also be set within other ranges as needed.

[0038] See also Figure 2 As shown, in some embodiments, the inner wall of the combustion chamber 2 is provided with a throat 23, the upper end of the throat 23 is connected to the lower end of the upper squeezing area 22, the throat 23 is in an inwardly convex arc, and the ratio of the distance from the center of the throat 23 to the top surface of the combustion chamber 2 to the depth of the combustion chamber 2 is 0.1 to 0.12.

[0039] In this embodiment, the throat 23 connects the upper squeeze flow area and the middle squeeze flow area. Specifically, its upper edge is connected to the lower edge of the upper squeeze flow area 22, and the lower edge is connected to the upper wall surface of the middle squeeze flow area 24; the ratio of the distance between the center of the throat 23 and the top surface of the combustion chamber 2 to the depth of the combustion chamber 2 is 0.1 to 0.12. By adopting a smaller depth ratio, a larger squeeze flow velocity is obtained near the compression top dead center, and a stronger squeeze flow motion is formed inside the combustion chamber 2, which increases the turbulent kinetic energy around the spark plug 5 at the ignition moment, and the flame propagation speed is fast, which is conducive to the formation of the fire core and the development of the flame in the early stage of combustion, and can effectively increase the combustion reaction rate and improve the thermal efficiency of the gas engine.

[0040] Furthermore, the throat 23 is in the shape of an arc convex inward, which is conducive to forming a stronger squeeze flow motion. In other embodiments, the throat 23 can also be designed into other shapes, for example, it can be conical or stepped; the ratio of the distance from the center of the throat 23 to the top surface of the combustion chamber 2 to the depth of the combustion chamber 2 is 0.1 to 0.12. In other embodiments, the ratio of the distance from the center of the throat 23 to the top surface of the combustion chamber 2 to the depth of the combustion chamber 2 can also be set within other ranges as needed.

[0041] See also Figure 2 As shown, in some embodiments, a central squeeze flow area 24 is provided in the middle of the inner wall of the combustion chamber 2, the upper end of the central squeeze flow area 24 is connected to the lower end of the throat 23, the central squeeze flow area 24 is conical, and the cross-sectional size gradually expands from top to bottom, and the angle between the cross-section of the wall of the central squeeze flow area 24 and the axis of the piston 1 is 25° to 28°.

[0042] In this embodiment, the middle squeeze flow area 24 of the combustion chamber 2 is located at the center of the outer side of the combustion chamber 2, the upper edge of the middle squeeze flow area 24 is connected to the lower part of the throat 23, and the lower edge is connected to the pit 25 of the combustion chamber 2; the middle squeeze flow area 24 is designed as a right conical inclined wall, the inner diameter increases from top to bottom, and the angle between the cross section and the axis of the piston 1 is 25 to 28 degrees. As the piston 1 moves upward, the upper squeeze flow area 22 and the middle squeeze flow area 24 work together to form a strong squeeze flow motion inside the combustion chamber 2, thereby increasing the turbulent kinetic energy around the spark plug at the ignition moment, which is beneficial to the formation of the fire core and the development of the flame in the early stage of combustion, and can effectively increase the combustion reaction rate and improve the thermal efficiency of the gas engine.

[0043] Furthermore, the middle squeeze flow area 24 is conical, and the cross-sectional size gradually expands from top to bottom, which is conducive to forming a stronger squeeze flow movement. In other embodiments, the middle squeeze flow area 24 can be designed to have other shapes, for example, it can be arc-shaped or stepped; the angle between the cross-section of the wall of the middle squeeze flow area 24 and the axis of the piston 1 is 25° to 28°. In other embodiments, the ratio of the diameter of the middle squeeze flow area 24 to the diameter of the piston 1 can also be set within other ranges as needed.

[0044] See also Figure 2 As shown, in some embodiments, a pit 25 is provided at the lower end of the inner wall of the combustion chamber 2, the upper end of the pit 25 is connected to the lower end of the middle squeezing area 24, the pit 25 is in an arc shape convex outward, and the ratio of the radius of the pit 25 to the diameter of the piston 1 is 0.07 to 0.08.

[0045] In this embodiment, the pit 25 of the combustion chamber 2 is located at the bottom of the combustion chamber 2, with its upper edge connected to the lower edge of the middle squeezing area 24, and the lower edge connected to the outer side of the spherical cap bottom surface 26 of the combustion chamber 2; the ratio of the radius of the pit 25 to the diameter of the piston 1 is 0.07~0.08, which can increase the squeezing area at the bottom of the combustion chamber 2 and the squeezing intensity inside the combustion chamber 2, increase the air flow velocity and turbulence intensity at the bottom of the combustion chamber 2, which is conducive to the flame developing in the direction away from the spark plug 5, and the flame is more evenly distributed in the space of the combustion chamber 2, thereby obtaining better gas economy and emissions, and can significantly improve the size of the turbulent kinetic energy in the cylinder.

[0046] Furthermore, the pit 25 is in the shape of an arc convex outward, which is conducive to forming a stronger squeeze flow motion. In other embodiments, the pit 25 can be designed into other shapes, such as a cone or a step-shaped shape; the ratio of the radius of the pit 25 to the diameter of the piston 1 is 0.07 to 0.08. In other embodiments, the ratio of the radius of the pit 25 to the diameter of the piston 1 can also be set within other ranges as needed.

[0047] See also Figure 2 As shown, in some embodiments, a spherical cap bottom surface 26 is provided at the bottom of the combustion chamber 2 , and the spherical cap bottom surface 26 is in an inwardly convex arc shape, and the ratio of the diameter of the spherical cap bottom surface 26 to the diameter of the piston 1 is 1.7 to 1.8.

[0048] In this embodiment, the spherical cap bottom surface 26 of the combustion chamber 2 is located at the bottom of the combustion chamber 2, and its outer edge is connected to the inner side of the pit 25 of the combustion chamber 2, and the inner edge is connected to the central boss of the combustion chamber; the bottom of the squeeze flow area at the lower part of the combustion chamber adopts a hemispherical cap design, and the ratio of the spherical cap arc diameter to the cylinder diameter is 1.7 to 1.8. The larger curvature radius can increase the height of the central boss of the combustion chamber, providing sufficient space for the flame to propagate in the longitudinal direction, and preventing the increase in heat transfer loss caused by the flame contacting the wall; at the same time, the hemispherical cap design increases the squeeze flow area at the bottom of the combustion chamber 2 and the squeeze flow intensity inside the combustion chamber 2, increases the air flow velocity and turbulence intensity at the bottom of the combustion chamber 2, which is conducive to the flame developing in the direction away from the spark plug, and the flame is more evenly distributed in the space of the combustion chamber 2, thereby obtaining better gas economy and emissions, and can significantly improve the size of the turbulent kinetic energy in the cylinder.

[0049] Furthermore, the bottom surface 26 of the spherical cap is in the shape of an arc convex inward, which is conducive to forming a stronger squeeze flow motion. In other embodiments, the bottom surface 26 of the spherical cap can be designed to be other shapes, for example, linear; the ratio of the spherical cap arc diameter to the cylinder diameter is 1.7 to 1.8. In other embodiments, the ratio of the spherical cap arc diameter to the cylinder diameter can also be set within other ranges as needed.

[0050] See also Figure 2As shown, in some embodiments, the axis of the spark plug 5 is parallel to the axis of the piston 1 , and the axis of the combustion chamber 2 is parallel to the axis of the piston 1 .

[0051] In this embodiment, the intake duct 3 and exhaust duct 4 of the combustion chamber 2 are vertical ducts, and the center axis of the piston, the center axis of the spark plug, and the axis of the combustion chamber are parallel but do not overlap. The axis of the combustion chamber 2 is biased toward the exhaust duct 4, and the axis of the spark plug 5 is biased toward the intake duct 3, which is convenient for installation and helps to make the flow field distribution in the cylinder more uniform. The turbulent kinetic energy on the side close to the exhaust duct 4 in the combustion chamber 2 is not much different from the turbulent kinetic energy on the side close to the intake duct 3. The fire core propagates more evenly, the flame in the combustion chamber 2 is more symmetrical, and the flame is evenly distributed in the space of the combustion chamber 2. The airflow in the combustion chamber 2 can be fully utilized, the thermal efficiency is high, the combustion cycle fluctuation is low, and the knock tendency is reduced.

[0052] The embodiment of the present invention provides a gas engine combustion chamber suitable for equivalence ratio combustion. By rationally organizing the airflow movement in the cylinder, the size and distribution of the turbulent kinetic energy in the cylinder are improved, and the airflow in the cylinder is rationally used, thereby improving the distribution of the flame in the entire combustion chamber space, optimizing the combustion process, shortening the combustion duration, improving thermal efficiency, reducing combustion cycle fluctuations, and reducing the tendency of knock. In order to achieve the above-mentioned purpose, the top surface of the piston 1 is connected to the bottom surface of the combustion chamber 2 through the upper squish area 22, the throat 23, the middle squish area 24, and the lower squish area in sequence. The upper squish area 22 of the combustion chamber 2 is located at the opening 21 at the top of the combustion chamber 2 at the top of the piston 1, and includes two arcs of equal diameter; the middle squish area 24 of the combustion chamber 2 includes the inclined wall of the right circular cone of the combustion chamber 2; the throat 23 connects the upper squish area 22 and the middle squish area 24; the lower squish area includes a pit 25 and a spherical cap bottom surface 26. Among them, the upper squeezing area 22 is located at the top of the piston 1 and is formed by two arcs of equal diameter connected tangentially. The upper edge of the upper arc is connected to the edge of the combustion chamber opening, the lower edge is connected to the lower arc, the upper edge of the lower arc is connected to the lower edge of the upper arc, and the lower edge is connected to the upper edge of the throat 23; the upper edge of the throat 23 is connected to the lower edge of the upper squeezing area, and the lower edge is connected to the upper wall of the upper squeezing area 22; the upper squeezing area 22 is a right conical inclined wall, located at the center position of the outer side of the combustion chamber 2, its upper edge is connected to the lower part of the throat 23, and the lower edge is connected to the pit 25; the upper edge of the pit 25 is connected to the lower edge of the upper squeezing area 22, and the lower edge is connected to the outer side of the spherical crown bottom surface 26; the spherical crown bottom surface 26 is located at the bottom of the combustion chamber 2, its outer edge is connected to the inner side of the pit 25, and the inner edge is connected to the central boss of the combustion chamber 2.

[0053] The gas engine using this invention has the following emission and fuel consumption performance: emissions have reached the China VI B emission standard, BTE reaches 42%, a 1% improvement over the original solution, and the knock index KP-PK value is 1.5-2. Compared with the existing technology, it has a significant improvement in gas consumption and a reduced knock tendency.

[0054] The principle of a gas engine combustion chamber suitable for equivalence ratio combustion provided by an embodiment of the present invention is as follows:

[0055] 1. The embodiment of the present invention improves the in-cylinder flow field distribution by offsetting the combustion chamber 2 and the spark plug 5 in opposite directions relative to the axis of the piston 1, thereby evenly distributing the turbulent kinetic energy throughout the entire combustion chamber 2, optimizing the combustion process, shortening the combustion duration, and improving gas economy. Furthermore, while ensuring engine reliability, the simultaneous offset design of the spark plug 5 and the combustion chamber 2 makes the flame more evenly distributed in the combustion chamber 2, reduces the combustion cycle variations caused by uneven combustion, and reduces the tendency to knock. This design can reduce the knock index KP-PK value from 3 to between 1.5 and 2, thereby reducing the occurrence of knock. Therefore, the present invention can significantly improve the engine's anti-knock performance and reduce the tendency to knock.

[0056] 2. In this embodiment of the present invention, the ratio of the lower end diameter of the upper squish zone 22 of the combustion chamber 2 to the cylinder diameter is 0.51-0.53. This smaller diameter ratio achieves a higher squish velocity near compression top dead center. The middle squish zone 24 of the combustion chamber 2 has a right conical sloping wall design, with an inner diameter that increases from top to bottom. The angle between the cross-section and the axis of the piston 1 is 25-28°. As the piston 1 moves upward, the upper squish zone 22 and the middle squish zone 24 work together to generate a strong squish motion within the combustion chamber 2. This increases the turbulent kinetic energy around the spark plug 5 at the moment of ignition, facilitating the formation of a fire core and flame development in the initial stages of combustion. Therefore, the present invention can significantly improve the thermal efficiency of gas engines.

[0057] 3. In the embodiment of the present invention, the bottom of the lower squeezing zone of the combustion chamber 2 adopts a hemispherical crown design, with the ratio of the arc diameter of the spherical crown to the cylinder diameter being 1.7-1.8. The larger radius of curvature can increase the height of the central boss of the combustion chamber 2, providing sufficient space for the flame to propagate in the longitudinal direction, and preventing the increase in heat transfer loss caused by the flame contacting the wall. At the same time, the hemispherical crown design increases the squeezing area at the bottom of the combustion chamber 2 and the squeezing intensity inside the combustion chamber, increasing the airflow velocity and turbulence intensity at the bottom of the combustion chamber 2, which is conducive to the flame developing in a direction away from the spark plug. At the same time, the right conical inclined wall design of the squeezing zone 24 in the middle of the combustion chamber increases the turbulence intensity in the cylinder, which is conducive to the flame developing toward the outside of the combustion chamber. In addition, the offset design of the combustion chamber 2 makes the turbulent kinetic energy in the entire combustion chamber 2 more uniform, and the flame is more evenly distributed in the space of the combustion chamber 2, thereby achieving better gas economy and emissions. Therefore, the present invention can significantly improve the turbulent kinetic energy in the cylinder.

[0058] In the description of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "upper" and "lower" is based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. Unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be internal communication between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0059] It should be noted that, in the present invention, relational terms such as "first" and "second" are merely used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element.

[0060] The foregoing description is intended only to provide specific embodiments of the present invention, which will enable those skilled in the art to understand and implement the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not intended to be limited to the embodiments shown herein, but is intended to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A gas engine combustion chamber suitable for equivalence ratio combustion, characterized in that: It includes: Piston (1); A combustion chamber (2) is arranged in the piston (1), the top of the combustion chamber (2) is provided with an opening (21), an intake passage (3) and an exhaust passage (4) are provided above the opening (21), and the axis of the combustion chamber (2) deviates from the axis of the piston (1) in a direction away from the intake passage (3) by a first preset distance; A spark plug (5) is provided above the combustion chamber (2), and the axis of the spark plug (5) deviates from the axis of the piston (1) by a second preset distance in a direction close to the intake passage (3); An upper squeezing flow area (22) is provided at the upper end of the inner wall of the combustion chamber (2); a portion of the upper squeezing flow area (22) close to the opening (21) protrudes inwardly, and a portion away from the opening (21) protrudes outwardly; and a ratio of a lower end diameter of the upper squeezing flow area (22) to a diameter of the piston (1) is 0.51 to 0.

53.

2. The gas engine combustion chamber suitable for equivalence ratio combustion according to claim 1, characterized in that: The ratio of the deviation distance between the axis of the spark plug (5) and the axis of the piston (1) to the diameter of the piston (1) is 0.01 to 0.

02.

3. The gas engine combustion chamber suitable for equivalence ratio combustion according to claim 1, characterized in that: The ratio of the deviation distance between the axis of the combustion chamber (2) and the axis of the piston (1) to the diameter of the piston (1) is 0.02 to 0.

04.

4. The gas engine combustion chamber suitable for equivalence ratio combustion according to claim 1, characterized in that: The inner wall of the combustion chamber (2) is provided with a throat (23), the upper end of the throat (23) is connected to the lower end of the upper squeezing flow area (22), the throat (23) is in the shape of an arc convex inwardly, and the ratio of the distance between the center of the throat (23) and the top surface of the combustion chamber (2) to the depth of the combustion chamber (2) is 0.1 to 0.

12.

5. The gas engine combustion chamber suitable for equivalence ratio combustion according to claim 4, characterized in that: A middle squeeze flow area (24) is provided in the middle of the inner wall of the combustion chamber (2), the upper end of the middle squeeze flow area (24) is connected to the lower end of the throat (23), the middle squeeze flow area (24) is conical, and the cross-sectional size gradually increases from top to bottom, and the angle between the tangent plane of the wall of the middle squeeze flow area (24) and the axis of the piston (1) is 25° to 28°.

6. The gas engine combustion chamber suitable for equivalence ratio combustion according to claim 5, characterized in that: A pit (25) is provided at the lower end of the inner wall of the combustion chamber (2), the upper end of the pit (25) is connected to the lower end of the middle squeezing flow area (24), the pit (25) is in an arc shape convex outwards, and the ratio of the radius of the pit (25) to the diameter of the piston (1) is 0.07-0.

08.

7. The gas engine combustion chamber suitable for equivalence ratio combustion according to claim 6, characterized in that: A spherical crown bottom surface (26) is provided at the bottom of the combustion chamber (2). The spherical crown bottom surface (26) is in an arc shape convex inwards, and the ratio of the diameter of the spherical crown bottom surface (26) to the diameter of the piston (1) is 1.7-1.

8.

8. The gas engine combustion chamber suitable for equivalence ratio combustion according to claim 1, characterized in that: The axis of the spark plug (5) is parallel to the axis of the piston (1), and the axis of the combustion chamber (2) is parallel to the axis of the piston (1).

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