CN116816534A - Engine cylinder cover and Miller circulation air inlet system - Google Patents

Abstract

The application relates to an engine cylinder cover and a Miller circulation air inlet system. The engine cylinder cover is used for installing on the cylinder of engine, the engine cylinder cover includes lid and water conservancy diversion spare, the lid is connected with the cylinder, be equipped with the air inlet with the cylinder intercommunication on the lid, be equipped with the intake duct of one end and air inlet intercommunication in the lid, the water conservancy diversion spare is located in the intake duct and is close to the air inlet setting, the water conservancy diversion spare has the water conservancy diversion face, the water conservancy diversion face is configured to make the air can circulate to the cylinder by the intake duct along the water conservancy diversion direction of water conservancy diversion face, wherein, the line between two points that follow water conservancy diversion direction each other on the periphery of water conservancy diversion face is first line, the line that defines perpendicular with the line between the centre of a circle of air inlet and the centre of a circle of cylinder is first tangent line, the contained angle between the orthographic projection of first line on the cross section of air inlet and the orthographic projection of first tangent line on the cross section of air inlet is less than or equal to 15 degrees. The air flow intensity in the cylinder can be improved only by additionally arranging the guide piece on the engine cylinder cover, and the structure is simple.

Description

Engine cylinder cover and Miller circulation air inlet system

Technical Field

The application relates to the technical field of engines, in particular to an engine cylinder cover and a Miller circulation air inlet system.

Background

Engines typically improve their economy, dynamics, and emissions performance by enhancing intake swirl. For this reason, an engine capable of improving the strength of the swirl is provided in the related art.

However, the engine structure provided in the related art is complicated.

Disclosure of Invention

Accordingly, it is necessary to provide an engine head and a miller cycle intake system that can improve the strength of the swirl and have a simple structure.

According to one aspect of the present application, there is provided an engine head for mounting on a cylinder of an engine, the engine head comprising:

the cover body is connected with the air cylinder, an air inlet communicated with the air cylinder is arranged on the cover body, and an air inlet channel with one end communicated with the air inlet is arranged in the cover body; and

a flow guide member disposed within the air intake duct and adjacent to the air intake port, the flow guide member having a flow guide surface configured to enable gas to flow from the air intake duct to the cylinder along a flow guide direction of the flow guide surface;

the connecting line between two points which are opposite to each other along the diversion direction on the periphery of the diversion surface is defined as a first connecting line, a straight line which is perpendicular to the connecting line between the circle center of the air inlet and the circle center of the air cylinder is defined as a first tangent line, and an included angle between the orthographic projection of the first connecting line on the cross section of the air inlet and the orthographic projection of the first tangent line on the cross section of the air inlet is smaller than or equal to 15 degrees.

According to the engine cylinder cover, the guide piece is arranged in the air inlet channel, so that gas flows into the cylinder along the guide direction of the guide surface when entering the cylinder under the guide effect of the guide piece, and the included angle between the orthographic projection of the first connecting line on the cross section of the air inlet and the orthographic projection of the first tangent line on the cross section of the air inlet is smaller than or equal to 15 degrees, so that the gas flows along the direction close to the circumferential direction of the cylinder, turbulence energy in the cylinder during top dead center is improved, mixing of the gas and fuel in the cylinder is promoted, and the economical efficiency, the dynamic property and the emission performance of the engine are improved. And the air flow intensity in the cylinder can be improved only by additionally arranging a guide piece in the air inlet channel, and the structure is simple.

In one embodiment, the flow guiding surface has a first end and a second end opposite to each other along the flow guiding direction, the first end is connected to one side inner wall of the air inlet channel, the second end extends toward the other side inner wall of the air inlet channel, and the second end is located between the first end and the air inlet in the axial direction of the air inlet.

In one embodiment, the included angle between the first connecting line and the cross section of the air inlet is greater than or equal to 30 degrees and less than or equal to 60 degrees.

In one embodiment, the distance between the flow guiding surface and the cross section of the air inlet along the axial direction of the air inlet gradually decreases from the first end to the second end.

In one embodiment, the flow guiding surface is configured as a plane; or (b)

The guide surface is recessed towards the guide piece along the direction perpendicular to the guide direction and the axial direction of the air inlet respectively; or (b)

The guide surface protrudes outwards from the guide piece along a direction perpendicular to the guide direction and the axial direction of the air inlet respectively.

In one embodiment, the orthographic projection area of the flow guide piece on the cross section of the air inlet is a, and the area of the cross section of the air inlet is b;

wherein, b is more than or equal to 40 percent and less than or equal to 50 percent.

In one embodiment, the cover and the flow guide member are manufactured by an integral molding process.

In one embodiment, the engine cylinder cover further comprises an intake valve, and the intake valve movably penetrates through the air inlet along the axial direction of the air inlet;

the guide piece is provided with a clearance channel penetrating through the guide piece along the axial direction of the air inlet, the air inlet valve movably penetrates through the avoidance channel, and is arranged at intervals along the radial direction of the air inlet and the flow guide piece.

In one embodiment, a valve disc capable of enabling the air inlet channel to be communicated with or isolated from the air cylinder is arranged on one end of the air inlet valve close to the air inlet;

the engine cylinder cover also comprises an air inlet seat ring arranged in the air inlet channel, the air inlet seat ring is positioned between the air inlet and the flow guide piece along the extending direction of the air inlet channel, and the air inlet seat ring can be matched with the valve disc so that the valve disc is isolated from the air inlet channel and the air cylinder.

According to another aspect of the application, there is provided a miller cycle intake system comprising an engine head according to any of the embodiments described above.

In one embodiment, the engine cylinder cover further comprises an intake valve, wherein the intake valve is movably arranged on the air inlet in a penetrating way along the axial direction of the air inlet so as to enable the air inlet channel to be communicated with or isolated from the air cylinder;

the Miller circulation air inlet system further comprises an air cylinder connected with the cover body and a piston movably arranged in the air cylinder;

the intake valve is configured to communicate the intake passage with the cylinder when the piston is at bottom dead center, and to move relative to the intake port to isolate the intake passage from the cylinder when the piston moves a first crank angle from the bottom dead center toward top dead center;

wherein the first crank angle is greater than or equal to 50 degrees and less than or equal to 90 degrees.

Drawings

FIG. 1 is a schematic diagram of an engine head and cylinder assembly in accordance with an embodiment of the present application.

Fig. 2 is a schematic view of the engine head in the embodiment shown in fig. 1.

Fig. 3 is a schematic view of the engine head of the embodiment of fig. 1 from another perspective.

FIG. 4 is a schematic diagram of the engine head and piston assembly of the embodiment of FIG. 1.

Fig. 5 is a schematic diagram of the engine head and piston assembly of the embodiment of fig. 1 from another perspective.

FIG. 6 is a schematic diagram illustrating the assembly of an intake valve with an intake runner in accordance with an embodiment of the present application.

Fig. 7 is the valve lift in the comparative example one and the embodiment one.

Fig. 8 shows the average turbulence in the cylinder in the first comparative example, the second comparative example and the first example.

Fig. 9 is the total in-cylinder mass in the comparative example one and the embodiment one.

Reference numerals illustrate:

100. an engine cylinder cover;

10. a cover body; 11. an air inlet; 12. an air inlet channel;

20. a flow guide; 21. a flow guiding surface; 21a, a first end; 21b, a second end; 22. a avoidance channel; 23. a first edge; 24. a second edge; 25. a bottom surface;

30. an intake valve; 31. a valve disc;

40. an air inlet seat ring;

200. a cylinder;

300. a piston;

A. a diversion direction; B. a first direction;

m, first connecting line, n and first tangent line.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The present application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit of the application, whereby the application is not limited to the specific embodiments disclosed below.

In the description of the present application, it should be understood that, if any, these terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., are used herein with respect to the orientation or positional relationship shown in the drawings, these terms refer to the orientation or positional relationship for convenience of description and simplicity of description only, and do not indicate or imply that the apparatus or element referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore should not be construed as limiting the application.

Furthermore, the terms "first," "second," and the like, if any, are used for descriptive purposes only and are 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 the description of the present application, the terms "plurality" and "a plurality" if any, mean at least two, such as two, three, etc., unless specifically defined otherwise.

In the present application, unless explicitly stated and limited otherwise, the terms "mounted," "connected," "secured," and the like are to be construed broadly. For example, the two parts can be fixedly connected, detachably connected or integrated; 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 application can be understood by those of ordinary skill in the art according to the specific circumstances.

In the present application, unless expressly stated or limited otherwise, the meaning of a first feature being "on" or "off" a second feature, and the like, is that the first and second features are either in direct contact or in indirect contact through an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

It will be understood that if an element is referred to as being "fixed" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. If an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein, if any, are for descriptive purposes only and do not represent a unique embodiment.

FIG. 1 is a schematic illustration of an engine head and cylinder assembly in accordance with an embodiment of the present application; FIG. 2 is a schematic view of the engine head of the embodiment of FIG. 1; fig. 3 is a schematic view of the engine head of the embodiment of fig. 1 from another perspective.

Referring to fig. 1-3, an engine cylinder head 100 according to an embodiment of the present application is configured to be mounted on a cylinder 200 of an engine, where the engine cylinder head 100 includes a cover body 10 and a flow guide 20.

The cover 10 is connected with the cylinder 200, an air inlet 11 (see fig. 2) communicated with the cylinder 200 is arranged on the cover 10, and an air inlet 12 with one end communicated with the air inlet 11 is arranged in the cover 10. A baffle 20 is disposed within the intake duct 12 and adjacent to the intake port 11, the baffle 20 having a baffle surface 21, the baffle surface 21 being configured to enable gas flow from the intake duct 12 to the cylinder 200 along a baffle direction a (i.e., direction a in fig. 2) of the baffle surface 21. Wherein, a line between two points opposite to each other along the flow guiding direction a on the outer periphery of the flow guiding surface 21 is defined as a first line m, a line perpendicular to a line between the center of the air inlet 11 and the center of the cylinder 200 is defined as a first line n, and an included angle between an orthographic projection of the first line m on the cross section of the air inlet 11 and an orthographic projection of the first line n on the cross section of the air inlet 11 is less than or equal to 15 degrees.

In the engine cylinder head 100, the guide 20 is disposed in the air inlet 12, so that the air flowing from the air inlet 12 to the cylinder 200 flows into the cylinder 200 along the guide direction a under the guide action of the guide 20. The line between two points on the outer periphery of the flow guiding surface 21 opposite to each other in the flow guiding direction a is defined as a first line m, and the extending direction of the orthographic projection of the first line m on the cross section of the gas inlet 11 is the direction of the velocity component of the gas on the plane parallel to the cross section of the gas inlet 11. And since the angle between the orthographic projection of the first line m on the cross section of the intake port 11 and the orthographic projection of the first tangential line n on the cross section of the intake port 11 is less than 15 degrees, that is, the angle between the direction of the velocity component of the gas on the plane parallel to the cross section of the intake port 11 and the direction passing through the center of the intake port 11 and tangential to the circumference of the cylinder 200 is less than or equal to 15 degrees. In this way, more gas flows along the direction similar to the circumferential direction of the cylinder 200 when entering the cylinder 200, so that turbulence energy in the cylinder 200 at the top dead center is improved, gas and fuel in the cylinder 200 are promoted to be mixed, combustion speed is accelerated, economical efficiency, dynamic property and emission performance of the engine are improved, and air flow intensity in the cylinder 200 can be enhanced only by additionally arranging the guide piece 20 in the air inlet channel 12, so that the engine cylinder cover 100 is simple in structure.

Optionally, the angle between the orthographic projection of the first line m on the cross section of the intake port 11 and the orthographic projection of the first tangential line n on the cross section of the intake port 11 is 5 degrees or less, so that the gas flows into the cylinder 200 from the intake port 12 more in the circumferential direction of the cylinder 200 when flowing into the cylinder 200.

In one embodiment, as shown in fig. 1, the orthographic projection of the first line m on the cross section of the air inlet 11 is parallel to the orthographic projection of the first line n on the cross section of the air inlet 11.

In some embodiments, as shown in fig. 2, the flow guiding surface 21 has a first end 21a and a second end 21b opposite to each other along the flow guiding direction a, the first end 21a is connected to one side inner wall of the air intake duct 12, the second end 21b extends toward the other side inner wall of the air intake duct 12, and the second end 21b is located between the first end 21a and the air intake 11 in the axial direction of the air intake 11. In this way, since the first end 21a is connected to the inner wall of the intake duct 12 on one side, the gas flows from the intake duct 12 into the cylinder 200, passes through the space between the second end 21b and the intake duct 12, and then enters the intake port 11. Since the second end 21b is located between the first end 21a and the intake port 11 in the axial direction of the intake port 11, the flow guide surface 21 is inclined with respect to the cross section of the intake port 11, and the flow guide surface 21 provides not only a flow guide effect in a direction close to the circumferential direction of the cylinder 200 but also a flow guide effect in the axial direction of the intake port 11 to facilitate the flow of the gas from the intake port 12 into the cylinder 200.

In some embodiments, as shown in fig. 2, the included angle between the first line m and the cross section of the intake port 11 is defined as α, which is 30 degrees or more and 60 degrees or less, so that the flow guiding surface 21 provides a more effective flow guiding effect for the gas flowing into the cylinder 200 from the intake port 12.

In some embodiments, as shown in fig. 2, from the first end 21a to the second end 21b, the distance between the flow guiding surface 21 and the cross section of the intake port 11 along the axial direction of the intake port 11 is gradually reduced to further improve the flow guiding effect of the gas introduced into the cylinder 200 from the intake port 12.

Alternatively, the flow guiding surface 21 may be configured as a plane or a curved surface.

Specifically, when the guide surface 21 is configured as a curved surface, the guide surface 21 may be recessed inward of the guide 20 in a first direction B (i.e., direction B in fig. 2) perpendicular to the axial direction of the intake port 11 and the guide direction a, respectively, and the guide surface 21 may also be protruded outward of the guide 20 in the first direction B.

In some embodiments, as shown in fig. 1-2, the orthographic projection area of the flow guiding member 20 on the cross section of the air inlet 11 is a, and the cross section area of the air inlet 11 is b, wherein a is equal to or greater than 40% b, so that the flow guiding member 20 has a strong flow guiding effect on the air flowing through the flow guiding surface 21.

Further, a is equal to or less than 50% b to avoid excessively low intake air amount caused by excessively large resistance of the air guide 20 to the air flowing from the intake duct 12 into the cylinder 200.

In some embodiments, the cover 10 and the guide 20 are manufactured by an integral molding process, so as to improve the connection reliability of the cover 10 and the guide 20 and reduce the production cost of the engine cylinder cover 100.

Optionally, the flow guiding member 20 is integrally cast with the cover body 10, so as to improve the overall structural strength of the cover body 10 and the flow guiding member 20. In the actual production process, the mold for pouring the cover body 10 in the related art may be adjusted so that the shape of the mold corresponds to the shape of the integrated structure of the cover body 10 and the guide member 20, resulting in a reduction in production cost.

In some embodiments, as shown in fig. 2, the flow guiding surface 21 is disposed on a side of the flow guiding element 20 away from the air inlet 11 along the axial direction of the air inlet 11, and a bottom surface 25 of the flow guiding element 20 on the side of the air inlet 11 away from the flow guiding surface 21 along the axial direction of the air inlet is parallel to the cross section of the air inlet 11, so that the flow guiding element 20 is more convenient to process.

In other embodiments, the bottom surface 25 of the baffle 20 may also be disposed obliquely with respect to the cross-section of the inlet 11.

In some embodiments, the orthographic projection of the baffle 21 onto the cross-section of the air inlet 11 coincides with the orthographic projection of the baffle 20 onto the cross-section of the air inlet 11.

Further, in the axial direction of the intake port 11, the first end 21a of the flow guiding surface 21 is configured to fit with a part of the intake duct 12 to block the flow of the air with the first end 21a, so that the air passing through the flow guiding surface 21 is guided from the first end 21a to the second end 21b.

FIG. 4 is a schematic illustration of the assembly of the engine head and piston of the embodiment of FIG. 1; FIG. 5 is a schematic view of the engine head and piston assembly of the embodiment of FIG. 1 from another perspective; FIG. 6 is a schematic diagram illustrating the assembly of an intake valve with an intake runner in accordance with an embodiment of the present application.

In some embodiments, as shown in connection with fig. 4-6, engine head 100 further includes an intake valve 30, with intake valve 30 movably disposed through intake port 11 in the axial direction of intake port 11. As shown in fig. 2-3, the guide member 20 is provided with a avoidance channel 22 penetrating through the guide member 20 along the axial direction of the air inlet 11, the air inlet valve 30 movably penetrates through the avoidance channel 22, and the air inlet valve 30 is arranged at intervals from the guide member 20 along the radial direction of the air inlet 11. In this way, the guide member 20 is penetrated along the axial direction of the air inlet 11 by arranging the avoidance channel 22 so that the air inlet valve 30 passes through the guide member 20 from the avoidance channel 22, and the air inlet valve 30 is arranged at intervals with the guide member 20 along the radial direction of the air inlet 11 so as to avoid the guide member 20 from influencing the movement of the air inlet valve 30 along the axial direction of the air inlet 11.

The intake valve 30 is configured to enable communication or isolation of the intake passage 12 from the cylinder 200, and the intake valve 30 is clearance-fitted with the bypass passage 22 when the intake valve 30 isolates the intake passage 12 from the cylinder 200.

Alternatively, when the intake valve 30 insulates the intake passage 12 from the cylinder 200, the fit clearance of the intake valve 30 to the avoidance passage 22 is 1mm to 2mm.

In some embodiments, as shown in connection with fig. 1 and 3, the shape of the section of the clearance channel 22 perpendicular to the axial direction of the air intake 11 is semicircular.

In some embodiments, as shown in connection with fig. 1-2, the intersection of the guide surface 21 and the bottom surface 25 of the guide 20 forms a first edge 23 and a second edge 24, the first edge 23 and the second edge 24 being located on opposite sides of the clearance channel 22 in the radial direction of the air inlet 11, respectively.

Alternatively, as shown in fig. 1, the orthographic projection of the first edge 23 on the cross section of the air intake 11 and the orthographic projection of the second edge 24 on the cross section of the air intake 11 each extend along a straight line.

In one embodiment, as shown in FIG. 1, the orthographic projection of the first edge 23 on the cross-section of the air inlet 11 and the orthographic projection of the second edge 24 on the cross-section of the air inlet 11 are collinear.

In other embodiments, the front projection of the first edge 23 on the cross-section of the air inlet 11 and the front projection of the second edge 24 on the cross-section of the air inlet 11 may also extend along curves (not shown in the figures).

In some embodiments, as shown in FIG. 6, a valve disc 31 is provided at an end of the intake valve 30 near the intake port 11 that enables the intake port 12 to communicate or be isolated from the cylinder 200 (see FIG. 1). As shown in fig. 2, the engine cylinder head 100 further includes an intake runner 40 disposed in the intake duct 12, and the intake runner 40 is located between the intake port 11 and the guide member 20 along the extending direction of the intake duct 12, and the intake runner 40 can cooperate with the valve disc 31 to isolate the intake duct 12 from the cylinder 200 by the valve disc 31. By providing the valve disc 31 at one end of the intake valve 30 in this manner, the intake valve 30 can close the intake port 11 with the valve disc 31, thereby isolating the intake port 12 from the cylinder 200. The intake port 11 is blocked by providing an intake runner 40 in the intake duct 12 to cooperate with the valve disc 31. And since the intake runner 40 is located between the intake port 11 and the deflector 20 in the extending direction of the intake duct 12, the deflector 20 is prevented from interfering with the intake runner 40.

Specifically, as shown in connection with fig. 1-2, along the axial direction of the air intake port 11, the first edge 23 and the second edge 24 of the deflector 20 are each spaced from the side of the intake runner 40 remote from the air intake port 11.

In some embodiments, as shown in fig. 1-2, the number of air inlets 11 is plural, and air inlets 12 are disposed in one-to-one correspondence with air inlets 11. For example, two intake ports 11 and two intake ports 12 are shown in fig. 1, and two exhaust ports spaced apart from the two intake ports 11 are also shown in fig. 1.

It will be appreciated that the number of air inlets 11 may be set according to the needs of use, and is not limited herein.

In some embodiments, the flow guiding elements 20 are disposed in the air inlet 12 in a one-to-one correspondence, and an angle between an orthographic projection of the first line m of each flow guiding element 20 on the cross section of the air inlet 11 and an orthographic projection of the first tangential line n of the corresponding air inlet 12 on the cross section of the air inlet 11 is less than or equal to 15 degrees. It should be noted that, for an engine with a strong supercharging system capability, there is enough supercharging pressure to supplement the intake air amount, so as to meet the full load requirement of the engine, a flow guiding member 20 may be disposed in each air inlet 12, so as to further improve the air flow strength in the cylinder 200, and better improve the performance of the engine.

In other embodiments, the number of baffle members 20 is less than the number of inlet passages 12 to enhance the macroscopic and microscopic air flow intensities within cylinder 200 to improve engine performance when the full load condition of the engine is highly demanding of the intake air amount and the supercharging system is difficult to meet.

According to another aspect of the present application, there is provided a miller cycle intake system comprising an engine head 100 according to any of the embodiments described above.

In some embodiments, as shown in fig. 6, the engine head 100 further includes an intake valve 30, where the intake valve 30 is movably disposed through the intake port 11 along an axial direction of the intake port 11, so that the intake port 12 is communicated or isolated from a cylinder 200 (see fig. 2), and the miller cycle intake system further includes the cylinder 200 connected to the head body 10 and a piston 300 movably disposed in the cylinder 200.

Fig. 7 is the valve lift in the comparative example one and the embodiment one.

Specifically, when the piston 300 is at bottom dead center, the intake valve 30 is configured to communicate the intake passage 12 with the cylinder 200, and when the piston 300 moves from the bottom dead center toward the top dead center by a first crank angle, the intake valve 30 is configured to move relative to the intake port 11 to isolate the intake passage 12 from the cylinder 200. In this way, the closing timing of the intake valve 30 of the miller cycle intake system is made later than the closing timing of the intake valve 30 of the non-miller cycle intake system in the related art to push the mixture in the cylinder 200 out of the cylinder 200 in the compression stroke of the piston 300, reducing the effective compression ratio, thereby alleviating the tendency of knocking.

For example, as shown in fig. 7, a non-miller cycle intake system is provided in comparative example one, and a miller cycle intake system is provided in embodiment one of the present application, in which the intake valve 30 closing timing is later than that in comparative example one.

Fig. 8 shows the average turbulence in the cylinder in the first comparative example, the second comparative example and the first example.

It should be noted that, since the miller cycle intake system in the related art opens the intake valve 30 in the compression stroke, the maintenance of tumble and vortex in the cylinder 200 is affected, the original squeeze process is destroyed, and the air flow intensity in the cylinder 200 at the top dead center is reduced, which is unfavorable for combustion. For example, as shown in fig. 8, a miller cycle intake system without the baffle 20 is provided in the second comparative example, in which the average turbulence in the cylinder 200 is lower than that in the first comparative example at the ignition timing (typically, in the range of 10 degrees to 30 degrees before the top dead center, 720CA at the top dead center, and 690CA to 710CA at the ignition timing in fig. 8), because the miller cycle in the second comparative example destroys the original extrusion process. Specifically, the extrusion process occurs after 540CA, so that after 540CA, the average turbulence in the first cylinder 200 of the comparative example decreases more slowly, and the average turbulence in the second cylinder 200 of the comparative example decreases more rapidly, and by the time of ignition, it appears that the average turbulence in the first cylinder 200 of the comparative example is higher than that of the second cylinder of the comparative example. In the present application, the engine cylinder cover 100 according to any one of the embodiments is adopted to greatly improve the movement strength of the air flow in the cylinder 200 by using the diversion effect of the diversion surface 21, so as to avoid the problem of lower movement strength of the air flow in the second comparative example. In particular, as shown in fig. 8, in the first embodiment of the present application, the average turbulence energy in the ignition timing cylinder 200 is greater than the average turbulence energy in the ignition timing cylinder 200 of the first and second comparative examples.

Fig. 9 is the total in-cylinder mass in the comparative example one and the embodiment one.

In addition, since the intake valve 30 of the related art non-miller cycle engine is close to closing at the bottom dead center of the intake stroke to complete the whole intake process, whereas the intake valve 30 of the related art miller cycle intake system is not closed at the bottom dead center of the intake stroke to move the piston 300 upward for a while after the bottom dead center to push the gas in the cylinder 200 out of the cylinder 200 from the intake valve 30 until the intake valve 30 is closed, the pushing of the gas in the cylinder 200 from the cylinder 200 is stopped, and thus the intake air amount of the related art miller cycle intake system is reduced as compared with the intake air amount of the related art non-miller cycle intake system, thereby requiring an increase in intake pressure to cause a large burden on the turbocharger. In the present application, since the engine head 100 according to any one of the embodiments is used, the intake resistance of the intake port 12 is increased by the guide 20, that is, the amount of intake air in the cylinder 200 in the intake stroke is reduced at the same intake pressure, and when the air flow flows from the cylinder 200 to the intake port 12, the resistance of the intake port 12 is also increased by the guide 20, so that the amount of air pushed out from the cylinder 200 is reduced. As such, the amount of gas entering the cylinder 200 from the intake duct 12 and the amount of gas pushed out of the cylinder 200 in the present application are reduced, so that the total mass of gas in the cylinder 200 is not affected. As shown in fig. 9 in particular, the difference between the total mass in the cylinder 200 in the first embodiment and the total mass in the cylinder 200 in the non-miller cycle intake system provided in the first comparative example is small.

In some embodiments, when the piston 300 moves from the bottom dead center to the top dead center by a first crank angle, which is greater than or equal to 50 degrees and less than or equal to 90 degrees, the intake valve 30 is configured to move relative to the intake port 11 to isolate the intake port 12 from the cylinder 200, so that the miller cycle intake system has a better intake backflow effect.

It should be noted that, the engine cylinder cover 100 provided by the present application may be applied to different miller cycle intake systems, as long as the intake valve 30 is closed late, for example, the magnitude of the first crank angle and the valve lift may all take other settings according to the use requirement, which is not limited herein.

Therefore, in the miller cycle intake system provided by the application, since the engine cylinder cover 100 according to any one of the embodiments is adopted to increase the air flow movement intensity in the cylinder 200 by the guide member 20 and increase the resistance of the air flowing into the cylinder 200 or flowing out of the cylinder 200 by the guide member 20, the influence of the insufficient air flow movement intensity on combustion is avoided, and the increase of the intake pressure due to the low intake air amount is avoided, which causes a large burden on the turbocharger. In this way, in the miller cycle air intake system provided by the application, the late closing of the air intake valve and the flow guide piece 20 are matched, so that the combustion speed is increased by enhancing the air flow movement intensity in the air cylinder 200 on the premise of not influencing the air intake amount.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The above examples illustrate only a few embodiments of the application, which are described in detail and are not to be construed as limiting the scope of the claims. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims (11)

1. An engine head for mounting on a cylinder of an engine, the engine head comprising:

the cover body is connected with the air cylinder, an air inlet communicated with the air cylinder is arranged on the cover body, and an air inlet channel with one end communicated with the air inlet is arranged in the cover body; and

a flow guide member disposed within the air intake duct and adjacent to the air intake port, the flow guide member having a flow guide surface configured to enable gas to flow from the air intake duct to the cylinder along a flow guide direction of the flow guide surface;

the connecting line between two points which are opposite to each other along the diversion direction on the periphery of the diversion surface is defined as a first connecting line, a straight line which is perpendicular to the connecting line between the circle center of the air inlet and the circle center of the air cylinder is defined as a first tangent line, and an included angle between the orthographic projection of the first connecting line on the cross section of the air inlet and the orthographic projection of the first tangent line on the cross section of the air inlet is smaller than or equal to 15 degrees.

2. The engine head according to claim 1, wherein the flow guide surface has a first end and a second end opposite to each other in the flow guide direction, the first end being connected to one side inner wall of the intake passage, the second end extending toward the other side inner wall of the intake passage, the second end being located between the first end and the intake port in the axial direction of the intake port.

3. The engine head of claim 2, wherein an included angle between the first line and a cross-section of the intake port is 30 degrees or more and 60 degrees or less.

4. The engine head of claim 2, wherein a distance between the flow directing surface and a cross section of the intake port along an axial direction of the intake port decreases progressively from the first end to the second end.

5. The engine head of claim 4, wherein the flow directing surface is configured as a planar surface; or (b)

The guide surface is recessed towards the guide piece along the direction perpendicular to the guide direction and the axial direction of the air inlet respectively; or (b)

The guide surface protrudes outwards from the guide piece along a direction perpendicular to the guide direction and the axial direction of the air inlet respectively.

6. The engine head according to any one of claims 1 to 5, characterized in that the orthographic projection area of the flow guide on the cross section of the intake port is a, and the area of the cross section of the intake port is b;

wherein, b is more than or equal to 40 percent and less than or equal to 50 percent.

7. The engine head of any one of claims 1 to 5, wherein the cover and the baffle are formed using an integral molding process.

8. The engine head according to any one of claims 1 to 5, further comprising an intake valve movably penetrating the intake port in an axial direction of the intake port;

the guide piece is provided with a clearance channel penetrating through the guide piece along the axial direction of the air inlet, the air inlet valve movably penetrates through the avoidance channel, and is arranged at intervals along the radial direction of the air inlet and the flow guide piece.

9. The engine cylinder head as set forth in claim 8, wherein a valve disc capable of communicating or isolating said intake passage with said cylinder is provided at an end of said intake valve adjacent to said intake port;

the engine cylinder cover also comprises an air inlet seat ring arranged in the air inlet channel, the air inlet seat ring is positioned between the air inlet and the flow guide piece along the extending direction of the air inlet channel, and the air inlet seat ring can be matched with the valve disc so that the valve disc is isolated from the air inlet channel and the air cylinder.

10. A miller cycle intake system comprising an engine head according to any of claims 1 to 9.

11. The miller cycle intake system of claim 10, wherein the engine head further comprises an intake valve movably disposed through the intake port in an axial direction of the intake port to communicate or isolate the intake port from the cylinder;

the Miller circulation air inlet system further comprises an air cylinder connected with the cover body and a piston movably arranged in the air cylinder;

the intake valve is configured to communicate the intake passage with the cylinder when the piston is at bottom dead center, and to move relative to the intake port to isolate the intake passage from the cylinder when the piston moves a first crank angle from the bottom dead center toward top dead center;

wherein the first crank angle is greater than or equal to 50 degrees and less than or equal to 90 degrees.