CN113404608B - Cylinder cover and gas engine - Google Patents

Abstract

The invention discloses a cylinder cover and a gas engine, wherein the cylinder cover comprises an air inlet throat and an exhaust throat, an air inlet valve seat ring is arranged in the air inlet throat, a tumble sharp angle is arranged on one side, far away from the exhaust throat, in the air inlet valve seat ring, the axial projection of the tumble sharp angle on the upper end surface of the air inlet valve seat ring is a sharp angle projection, the sharp angle projection forms a convex area which is protruded from the inner side edge of the air inlet valve seat ring to the center of the air inlet valve seat ring along the radial direction, and the width of the middle part of the sharp angle projection is larger than the widths of the two ends of the sharp angle projection. On the basis of the existing diesel engine, the tumble closed angle structure is arranged in the intake valve seat ring, so that intake airflow can be cast towards the exhaust throat when passing through the intake valve seat ring, the tumble strength in the cylinder is enhanced, and the heat efficiency of the gas engine is improved. Meanwhile, the invention also reduces the processing difficulty of the tumble sharp angle, so that the tumble sharp angle has higher form freedom degree.

Description

Cylinder cover and gas engine

Technical Field

The invention relates to the technical field of engines, in particular to a cylinder cover and a gas engine.

Background

With the development of gas engine technology, more and more gas engines are transformed on the basis of diesel engines at present. In the case of a diesel engine, the combustion mode is diffusion combustion, and a certain degree of swirl helps the oil bundles to mix with air, thereby improving the combustion process, so that an air inlet passage in the cylinder head of the engine is required to organize the air flow to generate a sufficient swirl ratio during the intake process. Wherein, the vortex refers to the gas rotational flow movement organized around the cylinder axial direction.

However, the combustion mode of the gas engine is premixed combustion, the requirement on the strength of vortex is not high, and small-scale turbulent motion is needed to form a flame wrinkle surface, so that the flame propagation speed is increased, and the heat efficiency is improved, wherein the turbulent motion refers to small rotational flow which is generated in a flow field when the air flow speed is high and has unfixed directions, and is different from laminar motion. For a gas engine, the strength of the vortex does not need to be increased, and the increase of the tumble strength in the cylinder can be beneficial to forming turbulence at the end of compression and generating enough turbulent kinetic energy when the piston moves up to the top dead center, so that the aim of optimizing combustion is fulfilled. Wherein, the tumble refers to the gas rotational flow motion of which the rotation central axis is vertical to the axial direction of the cylinder sleeve.

Therefore, for the existing gas engine cylinder cover which is designed by integrally modifying the diesel engine cylinder cover, tumble flow required by the gas engine is difficult to generate in the cylinder.

Therefore, how to improve the tumble strength in the cylinder of the gas engine is a technical problem that needs to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the present invention provides a cylinder head, which is improved in structure based on the existing diesel engine, so that the gas entering the cylinder generates the tumble motion required by the gas engine, and further, the thermal efficiency of the gas engine is improved. Another object of the present invention is to provide a gas engine comprising the above cylinder head.

In order to achieve the purpose, the invention provides the following technical scheme:

the cylinder cover comprises an air inlet throat and an air outlet throat, wherein an air inlet valve seat ring is arranged in the air inlet throat, a tumble closed angle is arranged on one side, far away from the air outlet throat, in the air inlet valve seat ring, the axial projection of the tumble closed angle on the upper end surface of the air inlet valve seat ring is a closed angle projection, a convex area which is formed by the edge on the inner side of the air inlet valve seat ring and protrudes to the center of the air inlet valve seat ring along the radial direction is formed by the closed angle projection, and the width of the middle part of the closed angle projection is larger than the width of the two ends of the closed angle projection.

Preferably, the sharp corner projects as a crescent shaped region with the concave side disposed towards the centre of the inlet valve seat insert.

Preferably, the edge of the sharp corner projection facing one side of the center of the intake valve seat ring is a sharp corner characteristic line, the connection line between the midpoint of the sharp corner characteristic line and the center of the intake valve seat ring is a sharp corner direction line, the included angle between the sharp corner direction line and the axis of the crankshaft is a sharp corner direction angle, the included angle between the connection line between the center of the intake throat and the center of the exhaust throat and the axis of the crankshaft is an intake and exhaust throat connection direction angle, and the intake and exhaust throat connection direction angle is less than or equal to 2 times the sharp corner direction angle.

Preferably, the minimum distance between the tumble flow sharp angle and the center line of the intake valve seat ring is greater than 0 and less than or equal to 0.5 times of the inner diameter of the intake valve seat ring.

Preferably, the throat that admits air is connected with the intake duct, the intake duct is close to the wall of tumble closed angle one side is first wall, be provided with the curved face portion of water conservancy diversion on the first wall, the curved face portion of water conservancy diversion is for relative first wall is to the sunken arc pit face of cylinder head bottom surface direction.

Preferably, the bottom hole of the air inlet throat is provided with an air inlet chamfer, and the center of the air inlet chamfer is offset towards the exhaust throat relative to the center of the air inlet throat.

Preferably, the cylinder head of the invention comprises a first intake throat and a second intake throat, the distance between the first intake throat and the cylinder head air inlet is less than the distance between the second intake throat and the cylinder head air inlet, a first intake valve seat ring is arranged in the first intake throat, a second intake valve seat ring is arranged in the second intake throat, and the height of the first intake valve seat ring from the bottom surface of the cylinder head is greater than the height of the second intake valve seat ring from the bottom surface of the cylinder head.

Preferably, the difference in height between the first and second intake valve races is greater than 0 and equal to or less than 0.2 times the intake valve diameter.

Preferably, the number of the air inlet throats is one or two or three.

Preferably, the cylinder head of the present invention includes at least two intake ports, and each of the intake ports is arranged separately.

Preferably, the number of the air inlet throats is at least two, and the tumble flow sharp angles of at least two air inlet throats are different.

Preferably, the cylinder head of the present invention comprises a head inlet port arranged at a side face or a top face or a bottom face of the cylinder head.

The invention provides a cylinder cover which comprises an air inlet throat and an air outlet throat, wherein an air inlet valve seat ring is arranged in the air inlet throat, a tumble sharp corner is arranged on one side, far away from the air outlet throat, in the air inlet valve seat ring, the axial projection of the tumble sharp corner on the upper end surface of the air inlet valve seat ring is a sharp corner projection, a protruding area protruding from the edge of the inner side of the air inlet valve seat ring to the center of the air inlet valve seat ring along the radial direction is formed by the sharp corner projection, and the width of the middle part of the sharp corner projection is larger than the widths of the two ends of the sharp corner projection.

The working principle of the invention is as follows:

when the engine cylinder inhales, the intake valve is opened, the intake airflow enters the cylinder from a gap between the intake valve seat ring and the intake valve, the tumble sharp corner arranged on the inner side of the intake valve seat ring enables the intake airflow to be extruded and cast towards the exhaust throat opening, so that most of the intake airflow enters the cylinder from the gap close to one side of the exhaust throat opening, the airflow far away from one side of the exhaust throat opening is reduced, and the airflows on two sides form large-scale tumble motion after entering the cylinder more easily.

On the basis of the existing diesel engine, the tumble closed angle structure is arranged in the intake valve seat ring, so that intake airflow can be thrown towards the exhaust throat when passing through the intake valve seat ring, the tumble strength in the cylinder is favorably enhanced, turbulent flow is favorably formed at the final stage of compression, and the heat efficiency of the gas engine is further improved.

According to the invention, the tumble flow sharp corner structure is arranged on the intake valve seat ring, the precision of the characteristic of the tumble flow sharp corner can be ensured by integrally processing the intake valve seat ring, the intake valve seat ring has higher form freedom degree, and the function of conveniently adjusting the tumble flow strength can be realized by rotating the relative position of the intake valve seat ring on the cylinder cover when a product is developed and assembled.

The invention also provides a gas engine comprising the cylinder cover. The derivation process of the beneficial effects generated by the gas engine is substantially similar to the derivation process of the beneficial effects brought by the cylinder cover, and therefore, the description is omitted.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic longitudinal cross-sectional view of a cylinder head according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of a tumble tip angle arrangement in an embodiment of the present invention;

FIG. 3 is a schematic structural diagram of an arrangement of arc-shaped concave pit surfaces in an air passage of a second cylinder head according to an embodiment of the present invention;

FIG. 4 is a schematic view of an arrangement of eccentric chamfers of a third cylinder head in an embodiment of the present invention;

FIG. 5 is a schematic illustration of a fourth cylinder head according to an embodiment of the present invention with two intake valve seats disposed at different heights;

FIG. 6 is a schematic illustration of a fourth cylinder head according to an embodiment of the present invention in which the two intake valve races are spaced from the cylinder head intake ports.

The meaning of the various reference numerals in figures 1 to 6 is as follows:

the air intake valve comprises a 1-air intake passage, a 2-air intake valve seat ring, a 3-air cylinder cover bottom surface, a 4-tumble sharp angle, a 5-crankshaft axis, a 20-air intake valve seat ring central line, a 21-first air intake valve seat ring, a 22-second air intake valve seat ring, a 23-first air exhaust valve seat ring, a 24-second air exhaust valve seat ring, a 41-sharp angle characteristic line, a 6-arc pit surface, a 71-first air intake chamfer, a 72-second air intake chamfer, a 211-first air intake throat center, a 221-second air intake throat center, a 231-first air exhaust throat center, a 241-second air exhaust throat center, an 11-first air intake passage, a 12-second air intake passage and a 13-cylinder cover air intake.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1 to 6, fig. 1 is a schematic longitudinal cross-sectional view of a cylinder head according to an embodiment of the present invention; FIG. 2 is a schematic diagram of a tumble tip angle arrangement in an embodiment of the present invention; FIG. 3 is a schematic structural diagram of an arrangement of arc-shaped concave pit surfaces in an air passage of a second cylinder head according to an embodiment of the present invention; FIG. 4 is a schematic view of an arrangement of eccentric chamfers of a third cylinder head in an embodiment of the present invention; FIG. 5 is a schematic illustration of a fourth cylinder head according to an embodiment of the present invention with two intake valve seats disposed at different heights; FIG. 6 is a schematic illustration of a fourth cylinder head according to an embodiment of the present invention in which the two intake valve races are spaced from the cylinder head intake ports.

The invention provides a cylinder cover which comprises an air inlet throat and an exhaust throat, wherein an air inlet valve seat ring 2 is arranged in the air inlet throat, a tumble sharp corner 4 is arranged on one side, far away from the exhaust throat, in the air inlet valve seat ring 2, the axial projection of the tumble sharp corner 4 on the upper end surface of the air inlet valve seat ring 2 is a sharp corner projection, the sharp corner projection forms a convex area which is protruded from the edge of the inner side of the air inlet valve seat ring 2 to the center of the air inlet valve seat ring 2 along the radial direction, and the width of the middle part of the sharp corner projection in the circumferential direction of the air inlet valve seat ring 2 is larger than the width of the two ends of the sharp corner projection.

The working principle of the invention is as follows:

when the engine cylinder breathes in, the intake valve is opened, and the air current of admitting air gets into in the cylinder by the gap between intake valve seat insert 2 and the intake valve, and the tumble closed angle 4 that the intake valve seat insert 2 inboard set up makes the air current of admitting air extrude to the direction of exhaust throat mouth and casts to make most minute air current of admitting air get into the cylinder from the gap that is close to exhaust throat mouth one side, and keep away from the air current of exhaust throat mouth one side then by reducing, the air current of these both sides forms large scale tumble motion more easily after getting into the cylinder.

On the basis of the existing diesel engine, the tumble sharp-angled structure 4 is arranged in the intake valve seat ring 2, so that intake airflow can be cast towards the exhaust throat when passing through the intake valve seat ring 2, the tumble strength in an air cylinder is enhanced, turbulent flow is formed in the last stage of compression, and the heat efficiency of a gas engine is improved.

The tumble flow sharp angle 4 is a key characteristic for generating tumble flow, the conventional scheme is that the tumble flow sharp angle 4 is formed in an air passage in a casting mode, the cast tumble flow sharp angle is limited by casting deviation, the consistency of different engines or different cylinders of the same engine cannot be guaranteed, the form freedom degree of the tumble flow sharp angle 4 is also limited by considering factors such as casting pattern drawing and the like, and in addition, the cast tumble flow sharp angle 4 does not have the function of adjusting the tumble flow strength. The intake valve seat ring 2 is provided with the tumble sharp angle 4 structure, so that the machining difficulty of the tumble sharp angle 4 is reduced, the precision of the characteristics of the tumble sharp angle 4 can be ensured by integrally machining the intake valve seat ring 2, the intake valve seat ring has higher form freedom, and the function of conveniently adjusting the tumble strength can be realized by rotating the relative position of the intake valve seat ring 2 on the cylinder cover when a product is developed and assembled.

The tumble flow cusp 4 in this embodiment may be formed integrally with the intake valve seat ring 2 by, for example, integral casting, forging, machining, or the like. By processing the tumble sharp corner 4 on the inner wall of the intake valve seat ring 2 on the side far away from the exhaust throat, the guide projection effect of the intake airflow at the tail end of the intake path can be realized, so that the intake airflow is guided to the exhaust side to the maximum extent, and the tumble motion is favorably formed in the cylinder.

It should be noted that, the tumble sharp corner 4 in this embodiment functions to extrude most of the intake air flow toward the exhaust throat before the intake air flow is injected into the cylinder, and the tumble sharp corner 4 capable of achieving the above function may be designed in various structural shapes, for example, one side edge of the tumble sharp corner 4 facing the center of the intake valve seat ring 2 is designed in an arc shape, a straight shape, a fold shape, or other curved structures. Preferably, the projection of the sharp corner in the present solution is a crescent-shaped area, and the concave side of the crescent-shaped area is arranged towards the center of the intake valve seat ring 2, i.e. one side edge of the tumble sharp corner 4 towards the center of the intake valve seat ring 2 is designed as a concave arc, as shown in fig. 2.

Preferably, the edge of the sharp corner projection facing to one side of the center of the intake valve seat ring 2 is a sharp corner characteristic line, the connecting line of the midpoint of the sharp corner characteristic line and the center of the intake valve seat ring 2 is a sharp corner direction line, the included angle between the sharp corner direction line and the crankshaft axis 5 is a sharp corner direction angle, and the included angle between the connecting line of the center of the intake throat and the center of the exhaust throat and the crankshaft axis 5 is an intake and exhaust throat connecting line direction angle. In a specific embodiment, the cylinder head has two intake valve seat rings and two exhaust valve seat rings, as shown in fig. 2, an included angle between a connecting line of a center of the first intake valve seat ring 21 (i.e., a first intake throat center 211) and a center of the first exhaust valve seat ring 23 (i.e., a first exhaust throat center 231) and the crankshaft axis 5 is a first intake and exhaust throat connecting line direction angle θ 1, an included angle between a connecting line of a center of the second intake valve seat ring 22 (i.e., a second intake throat center 221) and a center of the second exhaust valve seat ring 24 (i.e., a second exhaust throat center 241) and the crankshaft axis 5 is a second intake and exhaust throat connecting line direction angle θ 3, an included angle between a connecting line of a midpoint of a sharp corner feature line 41 in the first intake valve seat ring 21 and a center of the first intake valve seat ring 21 and the crankshaft axis 5 is a first sharp corner direction angle θ 2, and an included angle between a connecting line of a midpoint of a sharp corner feature line 41 in the second intake valve seat ring 22 and a center of the second intake valve seat ring 22 and the crankshaft axis 5 is a first angle θ 2 The direction angle θ 4 of the two sharp corners, preferably, the direction angle of the connecting line of the air inlet and outlet throats is less than or equal to 2 times of the direction angle of the sharp corners, that is, θ 1 (or θ 3) is less than or equal to 2 times of the direction angle of θ 2 (or θ 4), specifically, θ 1 (or θ 3) may be 2 times or 1.5 times or 1.2 times or 1.1 times or 0.9 times or 0.8 times or 0.5 times of the direction angle of θ 2 (or θ 4), so that the direction of the tumble flow sharp corner directed airflow may be further controlled, wherein the best directing effect is achieved when θ 1 (or θ 3) is 0.8-1.2 times of θ 2 (or θ 4).

Preferably, the minimum distance L1 between the tumble flow cusp 4 and the centerline of the intake valve seat ring 2 (intake valve seat ring centerline 20) is greater than 0 and equal to or less than 0.5 times the intake valve seat ring inner diameter D (the minimum diameter of the intake valve seat ring 2 and the intake valve sealing tapered surface), specifically, the minimum distance L1 may be 0.1 times, or 0.2 times, or 0.3 times, or 0.4 times, or 0.5 times the intake valve seat ring inner diameter D, the distance H1 between the tumble flow cusp 4 and the cylinder head bottom surface 3 may be greater than 0 and equal to or less than the intake valve seat ring inner diameter D, specifically, the distance H1 may be 0.1 times, or 0.2 times, or 0.3 times, or 0.4 times, or 0.5 times, or 0.6 times, or 0.7 times, or 0.8 times, or 0.9 times, or 1 times the intake valve seat ring inner diameter.

It should be noted that the tumble flow sharp corner 4 specifically includes an upper side flow guide surface and a lower side processing surface, the juncture of the upper side flow guide surface and the lower side processing surface is the edge of the tumble flow sharp corner 4 protruding toward the center of the intake valve seat ring 2, the tumble flow sharp corner 4 can be designed into different structures, and the lower side processing surface can be specifically designed into a rotary processing surface, or a plurality of planes connected in sequence, or other curved surface structures and the like. Preferably, in the scheme, the lower side processing surface of the tumble sharp angle 4 is a rotary processing surface surrounding a processing axis, the processing axis can be designed to be superposed, parallel or relatively obliquely arranged with the central line 20 of the intake valve seat ring, and the generatrix of the rotary processing surface is a straight line, a broken line or a curve.

It should be noted that, according to different bus shapes, the above-mentioned rotary processing surface can be designed into various different conical surface structures, preferably, the rotary processing surface in this scheme is a conical processing surface, the processing axis of the conical processing surface coincides with the intake valve seat axis 20, and the vertex of the conical processing surface is located above the intake valve seat 2. The specific shape of the tumble sharp angle 4 depends on the size of the cone angle of the conical processing surface, and the tumble sharp angle 4 is sharper when the cone angle is larger. Preferably, the value range of the cone angle of the conical processing surface in the scheme is 60-160 degrees, and within the range, the tumble sharp angle 4 can be ensured to have a sharp enough angle, so that the flow velocity mutation and the extrusion effect on the intake air flow are further strengthened.

As shown in fig. 3, in a preferred embodiment, the air inlet throat is connected to an air inlet duct 1, a wall surface of the air inlet duct 1 close to one side of the tumble sharp angle 4 is a first wall surface, a wall surface arranged in the air inlet duct 1 opposite to the first wall surface is a second wall surface, the first wall surface is provided with a flow guide curved surface portion, and the flow guide curved surface portion is an arc-shaped pit surface 6 which is recessed towards the bottom surface 3 of the cylinder head relative to the first wall surface. In this scheme, after the air current that admits air flows through arc pit face 6, arc pit face 6 casts the air current to contralateral intake duct wall, and tumble closed angle 4 that is located intake valve seat insert 2 further makes the air current to the extrusion of exhaust larynx mouth direction to the air current of flow direction exhaust larynx mouth direction has been strengthened, has reduced the air current that exhaust larynx mouth one side was kept away from to the intake larynx mouth, and this both sides air current forms stronger tumble motion after getting into the cylinder, thereby satisfies gas engine's combustion demand.

Preferably, the deepest part of the arc-shaped pit surface 6, which is sunken relative to the first wall surface, is a pit position point, and the distance L2 between the pit position point and the central line 20 of the intake valve seat ring is 0.5-3 times of the inner diameter D of the intake valve seat ring, specifically, the distance L2 may be 0.5 times, 0.8 times, 1 times, 1.5 times, 2 times, 2.5 times or 3 times of the inner diameter of the intake valve seat ring. The distance H2 between the pit position point and the cylinder head bottom surface 3 is greater than 0 and less than or equal to the intake valve seat inner diameter D, specifically, the distance H2 can be 0.1 times, or 0.2 times, or 0.3 times, or 0.4 times, or 0.5 times, or 0.6 times, or 0.7 times, or 0.8 times, or 0.9 times, or 1 times the intake valve seat inner diameter.

In another preferred embodiment, the bottom hole of the inlet throat is provided with an inlet chamfer, and the center of the inlet chamfer is offset relative to the center of the inlet throat in the direction of the outlet throat, i.e. the inlet chamfer is designed as an eccentric chamfer relative to the inlet throat. So set up for be greater than the gap of keeping away from exhaust larynx mouth one side between intake larynx mouth and the (air) intake valve near the gap of exhaust larynx mouth one side, thereby can guide most part to admit air and flow to the motion of exhaust larynx mouth direction, simultaneously, still because be provided with the tumble closed angle 4 structure that is used for the extruded air current in the (air) intake valve seat circle 2, make the guide effect of the air current of admitting air further promote, and then be favorable to forming the tumble motion of large scale in the cylinder.

Preferably, the included angle between the connecting line of the center of the air inlet throat and the center of the exhaust throat and the axis 5 of the crankshaft is the connecting direction angle of the air inlet throat and the exhaust throat, the included angle between the connecting line of the center of the air inlet chamfer and the center of the air inlet throat and the axis 5 of the crankshaft is the chamfer direction angle, and the connecting direction angle of the air inlet throat and the exhaust throat is less than or equal to 2 times of the chamfer direction angle. In one embodiment, the cylinder head has two intake throats and two exhaust throats, as shown in fig. 4, the angle between the connecting line of the first intake throat center 211 and the first exhaust throat center 231 and the crankshaft axis 5 is a first intake and exhaust throat connecting direction angle θ 1, the angle between the connecting line of the second intake throat center 221 and the second exhaust throat center 241 and the crankshaft axis 5 is a second intake and exhaust throat connecting direction angle θ 3, the angle between the connecting line of the center of the first intake chamfer 71 and the first intake throat center 211 and the crankshaft axis 5 is a first chamfer direction angle θ 5, the angle between the connecting line of the center of the second intake chamfer 72 and the second intake throat center 221 and the crankshaft axis 5 is a second chamfer direction angle θ 6, preferably, the intake and exhaust throat connecting direction angle is 2 times or less of the chamfer direction angle, that is, θ 1 (or θ 3) 2 times or less of θ 5 (or θ 6), specifically, θ 1 (or θ 3) may be 2 times or 1.5 times or 1.2 times or 1.1 times or 0.9 times or 0.8 times or 0.5 times θ 5 (or θ 6).

It should be noted that the air inlet chamfer of the present invention may be designed as a circular rotary chamfer or a non-circular chamfer structure, and for convenience of processing, the air inlet chamfer is preferably a circular rotary chamfer, that is, the air inlet chamfer is a chamfer structure obtained by removing cylinder head material and processing the cylinder head material with a rotary characteristic.

The chamfer structure with different longitudinal section shapes can be obtained according to different rotary processing surfaces, for example, after the cylinder cover material is removed by adopting a conical rotary processing surface, the longitudinal section of the obtained chamfer structure is in a linear structure. Preferably, the longitudinal section of the air inlet chamfer is a straight line or a curve.

Further preferably, the longitudinal section of the air inlet chamfer is a curve protruding towards the inner direction of the cylinder, in the scheme, the chamfer surface protruding towards the inner side of the cylinder can prevent the airflow from flowing and separating when the airflow passes through the chamfer.

It should be noted that the rotation center line of the air inlet chamfer may be arranged in parallel with the axis of the air inlet throat, or may be arranged in an inclined manner with respect to the axis of the air inlet throat.

Preferably, the revolution center line of the air inlet chamfer is obliquely arranged relative to the axis of the air inlet throat, and the lower end opening of the air inlet chamfer is arranged towards the direction of the exhaust throat, so that a wider chamfer surface can be machined at the edge of one side of the air inlet throat close to the exhaust throat, and meanwhile, the transition between the chamfer surface at the side and the bottom surface of the cylinder cover and the wall surface of the air inlet throat is smoother, thereby reducing the kinetic energy loss when airflow flows through the air inlet chamfer.

Preferably, the angle of inclination of the inlet chamfer centre of gyration relative to the inlet throat axis is greater than 0 ° and equal to or less than 30 °, in particular 30 ° or 20 ° or 10 ° or 5 °.

It should be noted that the cylinder head provided by the present invention may be applied to a two-valve engine or a multi-valve engine, that is, the number of the intake throats may be one or two or three or more, and the number of the exhaust throats may also be one or two or more, which is not described herein again.

In a preferred embodiment, as shown in fig. 5 and 6, the cylinder head of the invention comprises a first air inlet throat and a second air inlet throat, the distance L5 between the first air inlet throat and the cylinder head air inlet 13 is smaller than the distance L6 between the second air inlet throat and the cylinder head air inlet 13, a first air inlet valve seat ring 21 is arranged in the first air inlet throat, a second air inlet valve seat ring 22 is arranged in the second air inlet throat, and the height H4 of the first air inlet valve seat ring 21 from the bottom surface 3 of the cylinder head is larger than the height H5 of the second air inlet valve seat ring 22 from the bottom surface 3 of the cylinder head. The first air inlet throat is connected with a first air inlet channel 11, the second air inlet throat is connected with a second air inlet channel 12, and the first air inlet channel 11 and the second air inlet channel 12 are both connected to a cylinder cover air inlet 13.

Install the intake valve seat circle in the throat mouth of admitting air for with the on-off control of intake valve cooperation switching in order to realize admitting air, the throat mouth of admitting air is connected with the intake duct and is used for guiding the inlet airflow, cylinder cap air inlet 13 is the air inlet of intake duct, the line of the center of first throat mouth of admitting air and the center of second throat mouth of admitting air is certain angle with engine crankshaft axis, must lead to the distance of one of them throat mouth of admitting air and cylinder cap air inlet 13 to be greater than the distance of another throat mouth of admitting air and cylinder cap air inlet 13, the distance L6 of second throat mouth of admitting air and cylinder cap air inlet 13 in this scheme is greater than the distance L5 of first throat mouth of admitting air and cylinder cap air inlet 13, as shown in figure 6. The height H4 of the first intake valve seat ring 21 from the bottom surface 3 of the cylinder head, which is closer to the cylinder head intake port 13, is designed to be higher than the height H5 of the second intake valve seat ring 22 from the bottom surface 3 of the cylinder head, and the function of the scheme is to improve the flow capacity of the air passage to the maximum extent on the premise of ensuring the air passage tumble ratio. The principle is that the first air inlet channel 11 connected with the first air inlet throat is designed to be shorter and thicker due to the fact that the distances from the two air inlet valve seat rings to the air inlet 13 of the cylinder cover are different, and therefore, no space is provided for changing the shape of the air channel so that tumble flow can be generated more favorably. Therefore, the height H4 of the first intake valve seat ring 21 from the bottom surface 3 of the cylinder cover is increased, so that the flow guiding length of the guiding wall below the first intake valve seat ring 21 is further prolonged in the opening process of the valve, and tumble flow is more favorably generated. Meanwhile, the air flow is guided by the guide wall, so that the movement towards a target direction (towards the exhaust throat) is facilitated, and the air flow interference in the direction of the central connecting line of the two intake valves can be reduced.

Preferably, the difference in height between the first intake valve seat insert 21 and the second intake valve seat insert 22 is greater than 0 and equal to or less than 0.2 times the intake valve diameter.

It should be noted that, for a cylinder head having two or three or more intake throats, the number of intake ports 1 is two or three or more, the respective intake ports 1 may be arranged in a spaced manner, or upstream portions (i.e., a section near the head intake port 13) of the respective intake ports 1 may be communicated with each other to form an overall intake section.

It should be noted that, when the number of the intake throats in the present invention is two, three, or more, each intake throat or the corresponding intake valve seat ring or intake duct may be designed to have the same structure, or at least two intake throats or at least two intake valve seats may be designed to have an asymmetric structure, or the intake duct corresponding to at least two intake throats may be designed to have an asymmetric structure. The tumble flow cusps in each intake valve seat insert may all adopt the same structure or arrangement, or may adopt different structures or arrangements, for example, for a cylinder head structure with two intake throats, the cusp characteristic line 41 of the tumble flow cusp 4 of one intake valve seat insert 2 is an arc, and the cusp characteristic line 41 of the tumble flow cusp 4 of the other intake valve seat insert 2 is designed as a broken line.

Preferably, the cylinder head of the present invention includes a head intake port 13 (i.e., an intake port of an intake passage), and the head intake port 13 is generally disposed at a side surface of the cylinder head, but the cylinder head of the present invention may also dispose the head intake port 13 at a top surface or a bottom surface of the cylinder head, thereby facilitating mounting arrangements of engines of different models.

The invention also provides a gas engine comprising the cylinder cover. The derivation process of the beneficial effects generated by the gas engine is substantially similar to the derivation process of the beneficial effects brought by the cylinder cover, and therefore, the description is omitted.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (10)

1. A cylinder cover comprises an air inlet throat and an air outlet throat, wherein an air inlet valve seat ring is arranged in the air inlet throat, and the cylinder cover is characterized in that a tumble flow sharp corner is arranged on one side, far away from the air outlet throat, in the air inlet valve seat ring, the axial projection of the tumble flow sharp corner on the upper end surface of the air inlet valve seat ring is a sharp corner projection, the sharp corner projection forms a convex area which is convex from the inner side edge of the air inlet valve seat ring to the center of the air inlet valve seat ring along the radial direction, and the width of the middle part of the sharp corner projection is greater than the widths of the two ends of the sharp corner projection;

the air inlet structure comprises a cylinder cover, an air inlet, a cylinder cover, two air inlet throats, a first air inlet seat ring, a second air inlet seat ring and a second air inlet seat ring, wherein the number of the air inlet throats is two, the first air inlet throats and the second air inlet throats are respectively a first air inlet throat and a second air inlet throat, the distance between the first air inlet throat and the air inlet of the cylinder cover is smaller than the distance between the second air inlet throat and the air inlet of the cylinder cover, the first air inlet throat is internally provided with the first air inlet seat ring, the second air inlet seat ring is internally provided with the second air inlet seat ring, and the height from the first air inlet seat ring to the bottom surface of the cylinder cover is larger than the height from the second air inlet seat ring to the bottom surface of the cylinder cover.

2. The cylinder head of claim 1, wherein the pointed projection is a crescent shaped region with the concave side disposed toward the center of the intake valve seat insert.

3. The cylinder head according to claim 1, wherein an edge of the sharp corner projection on one side toward the center of the intake valve seat ring is a sharp corner feature line, a connecting line between a midpoint of the sharp corner feature line and the center of the intake valve seat ring is a sharp corner direction line, an included angle between the sharp corner direction line and a crankshaft axis is a sharp corner direction angle, an included angle between a connecting line between the center of the intake throat and the center of the exhaust throat and the crankshaft axis is an intake and exhaust throat connecting direction angle, and the intake and exhaust throat connecting direction angle is 2 times or less of the sharp corner direction angle.

4. The cylinder head of claim 1, wherein the tumble tip angle is a minimum distance from a centerline of the intake valve seat insert that is greater than 0 and equal to or less than 0.5 times an intake valve seat insert inner diameter.

5. The cylinder cover according to claim 1, wherein the air inlet throat is connected with an air inlet channel, the wall surface of the air inlet channel close to one side of the tumble closed angle is a first wall surface, a flow guide curved surface part is arranged on the first wall surface, and the flow guide curved surface part is an arc-shaped pit surface which is concave towards the bottom surface of the cylinder cover relative to the first wall surface.

6. The cylinder head of claim 1, wherein the bottom hole of the intake throat is provided with an intake chamfer, and a center of the intake chamfer is offset toward the exhaust throat with respect to a center of the intake throat.

7. The cylinder head of claim 1, including at least two intake ports, and wherein each of the intake ports is spaced apart.

8. The cylinder head according to claim 1, wherein the tumble flow cusps of the two intake throats are different.

9. The cylinder head of claim 1, including a head inlet port disposed at a side or top or bottom surface of the cylinder head.

10. A gas engine, characterized by comprising a cylinder head according to any one of claims 1 to 9.

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