JP2022186334A - cylinder head - Google Patents

Abstract

To making the suppression of obstructing a flow of intake air by a valve seat and the suppression of deteriorating the holding force of the valve seat by a cylinder head, compatible.SOLUTION: A cylinder head is equipped with an intake port connected to a combustion chamber, an annular valve seat in which an intake valve opening/closing the intake port can be seated, and an installing portion that is provided around an opening portion on the combustion chamber side of the intake port and to which the valve seat is installed. The valve seat has an annular projection that is disposed on an outer peripheral side of the valve seat and projects out in an axial direction of the valve seat. The installing portion has an annular groove capable of storing the annular projection of the valve seat, and an outer peripheral surface of the annular projection contacts with a first inner surface on an outer peripheral side of the annular groove while the valve seat is installed to the installing portion.SELECTED DRAWING: Figure 9

Description

The present invention relates to cylinder heads.

An intake port and the like are formed in the cylinder head of the engine. The intake valve opens and closes an opening of the intake port on the side of the combustion chamber. An annular valve seat is provided around this opening. For example, Patent Literature 1 discloses an example of a valve seat for an engine. When the intake valve closes its opening, the intake valve seats on the valve seat.

JP-A-62-23512

Generally, the length direction of the intake port is inclined with respect to the normal direction of the opening of the intake port. Therefore, part of the inner peripheral surface of the valve seat provided in the opening protrudes inward with respect to the inner surface of the intake port. As a result, the intake air introduced into the combustion chamber from the intake port may hit the protruding portion of the valve seat, and the flow of the intake air introduced into the combustion chamber may be obstructed. If the flow of intake air is obstructed, it becomes difficult to form an appropriate tumble flow, and as a result, there is a risk that combustion efficiency will decrease.

Therefore, it is conceivable to reduce the height of the valve seat, which is the width of the valve seat in the axial direction. Reducing the height of the valve seat reduces the amount of protrusion of the valve seat with respect to the inner surface of the intake port, making it difficult for the intake air introduced from the intake port into the combustion chamber to hit the protruding portion of the valve seat. As a result, obstruction of the flow of intake air can be suppressed.

However, if the height of the valve seat is lowered, the contact area between the cylinder head and the valve seat will decrease when the valve seat is press-fitted into the cylinder head around the opening of the intake port. The holding force with which the head holds the valve seat is reduced. As a result, the valve seat may fall off from the cylinder head in some cases.

SUMMARY OF THE INVENTION Accordingly, the present invention provides a cylinder head that is capable of both suppressing the flow of intake air from being blocked by a valve seat and suppressing a decrease in the holding force of the valve seat by the cylinder head. The purpose is to

In order to solve the above problems, a cylinder head according to one embodiment of the present invention includes:
an intake port connected to the combustion chamber;
an annular valve seat on which an intake valve that opens and closes the intake port can be seated;
a mounting portion provided around an opening of the intake port on the side of the combustion chamber and to which the valve seat is mounted;
with
The valve seat has an annular protrusion arranged on the outer peripheral side of the valve seat and protruding in the axial direction of the valve seat,
the mounting portion has an annular groove capable of accommodating the annular projection of the valve seat,
With the valve seat attached to the attachment portion, the outer peripheral surface of the annular projection is in contact with the first inner surface on the outer peripheral side of the annular groove.

Advantageous Effects of Invention According to the present invention, it is possible to prevent the flow of intake air from being obstructed by a valve seat and to prevent a decrease in the holding force of the valve seat by the cylinder head.

FIG. 1 is a schematic diagram showing the configuration of an engine according to this embodiment. FIG. 2 is a schematic enlarged view of an intake port in the cylinder head of the first comparative example. FIG. 3 is a schematic enlarged view of an intake port in a cylinder head of a second comparative example. FIG. 4 is a schematic enlarged view of an intake port in a cylinder head of a third comparative example. FIG. 5 is a schematic enlarged view of an intake port in the cylinder head of this embodiment. FIG. 6 is a perspective view of the valve seat according to this embodiment. FIG. 7 is a detailed enlarged sectional view of the opening of the intake port in the cylinder head of this embodiment. FIG. 8 is an internal plan view of the cylinder head viewed from the combustion chamber side. FIG. 9 is a detailed enlarged cross-sectional view of the opening of the intake port with the valve seat installed. FIG. 10 is a diagram showing the relationship between the amount of intake air introduced into the combustion chamber and the strength of the tumble flow of the intake air introduced into the combustion chamber.

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in such embodiments are merely examples for facilitating understanding of the invention, and do not limit the invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are given the same reference numerals to omit redundant description, and elements that are not directly related to the present invention are omitted from the drawings. do.

FIG. 1 is a schematic diagram showing the configuration of an engine 10 according to this embodiment. The engine 10 is mounted on a vehicle, for example. Engine 10 includes cylinder block 20 , pistons 22 , cylinder head 24 , intake valves 26 and exhaust valves 28 .

A plurality of cylinders 30 are formed in the cylinder block 20 . The piston 22 is slidably housed in the cylinder 30 and can reciprocate in the axial direction of the cylinder 30 . The piston 22 is connected to a crankshaft (not shown) via a connecting rod 32 . The crankshaft rotates according to the reciprocating motion of piston 22 .

The cylinder head 24 is arranged on the side of the cylinder block 20 opposite to the crankshaft. The cylinder head 24 is arranged on the cylinder 30 so as to cover the upper opening of the cylinder 30 and is connected to the cylinder block 20 . The combustion chamber 34 is a space surrounded by the inner surface of the cylinder 30 , the inner surface of the cylinder head 24 and the crown surface of the piston 22 .

Cylinder head 24 has an intake port 40 and an exhaust port 42 . The intake port 40 and the exhaust port 42 communicate with the combustion chamber 34 . Specifically, the intake port 40 is connected to the combustion chamber 34 through an opening 44a of the intake port 40 on the combustion chamber 34 side. The exhaust port 42 is connected to the combustion chamber 34 through an opening 44b of the exhaust port 42 on the combustion chamber 34 side.

The intake valve 26 is provided in the intake port 40 and opens and closes an opening 44 a of the intake port 40 . When the opening 44 a of the intake port 40 is opened by the intake valve 26 , air is introduced into the combustion chamber 34 through the intake port 40 . The exhaust valve 28 is provided in the exhaust port 42 and opens and closes the opening 44 b of the exhaust port 42 . When the opening 44 b of the exhaust port 42 is opened by the exhaust valve 28 , gas within the combustion chamber 34 is discharged through the exhaust port 42 .

The cylinder head 24 includes a mounting portion 50a on the intake port 40 side and a valve seat 52a on the intake port 40 side. The mounting portion 50a is provided around the opening 44a of the intake port 40 on the combustion chamber 34 side. The mounting portion 50a is formed in an annular shape surrounding the opening 44a. The mounting portion 50a is recessed on the side opposite to the combustion chamber 34, for example. The valve seat 52a is formed in an annular shape. The valve seat 52a is attached to the attachment portion 50a. The valve seat 52a is configured so that the intake valve 26 can be seated thereon. The intake valve 26 closes the opening 44a of the intake port 40 by contacting the valve seat 52a. The valve seat 52a on the side of the intake port 40 will be detailed later.

The cylinder head 24 includes a mounting portion 50b on the exhaust port 42 side and a valve seat 52b on the exhaust port 42 side. The mounting portion 50b is provided around the opening 44b of the exhaust port 42 on the combustion chamber 34 side. The mounting portion 50b is formed in an annular shape surrounding the opening 44b. The mounting portion 50b is recessed on the side opposite to the combustion chamber 34, for example. The valve seat 52b is formed in an annular shape. The valve seat 52b is attached to the attachment portion 50b. The valve seat 52b is configured so that the exhaust valve 28 can be seated thereon. The exhaust valve 28 closes the opening 44b of the exhaust port 42 by contacting the valve seat 52b.

The cylinder head 24 is provided with injectors 60 and spark plugs 62 . The injector 60 is arranged with the injection port directed toward the combustion chamber 34 . The injector 60 injects fuel such as gasoline into the combustion chamber 34 at a predetermined timing. The spark plug 62 is arranged with its electrode facing the combustion chamber 34 . The spark plug 62 ignites and burns the mixed gas of air and fuel in the combustion chamber 34 at a predetermined timing. Such combustion reciprocates the piston 22 within the cylinder 30 .

Next, cylinder heads according to first to third comparative examples will be described with reference to FIGS. 2 to 4. FIG. Then, the cylinder head 24 according to the present embodiment will be described in detail with reference to FIG. 5 while comparing with these first to third comparative examples.

FIG. 2 is a schematic enlarged view of the intake port 40 in the cylinder head A10 of the first comparative example. The cylinder head A10 of the first comparative example includes the valve seat B10 of the first comparative example. The valve seat B10 has a height H1. In this specification, the height of the valve seat means the width of the valve seat in the axial direction. The height H1 of the valve seat B10 is, for example, 6 mm.

In general, the lengthwise direction of the intake port 40 is inclined with respect to the normal line direction of the opening 44a of the intake port 40 . Therefore, a part of the inner peripheral surface of the valve seat B10 provided in the opening 44a protrudes with respect to the inner surface of the intake port 40. As shown in FIG. In FIG. 2 , the inner peripheral surface of the upper right portion of the valve seat B10 protrudes inward with respect to the inner surface of the intake port 40 . As a result, as shown by the dashed arrow in FIG. 2, the intake air introduced into the combustion chamber 34 from the intake port 40 hits the protruding portion of the valve seat B10, changes the flow of the intake air, and weakens the momentum. The flow of intake air introduced to 34 may be obstructed. If the flow of intake air is obstructed, it becomes difficult to form an appropriate tumble flow, and as a result, there is a risk that combustion efficiency will decrease.

FIG. 3 is a schematic enlarged view of the intake port 40 in the cylinder head A12 of the second comparative example. The cylinder head A12 of the second comparative example includes the valve seat B12 of the second comparative example. The valve seat B12 is a laser clad valve seat formed by spraying a predetermined alloy into the opening 44a using laser clad technology. In this valve seat B12, the inner peripheral surface of the valve seat B12 hardly protrudes from the inner surface of the intake port 40. As shown in FIG. Therefore, as indicated by the dashed arrow in FIG. 3, the intake air introduced into the combustion chamber 34 from the intake port 40 does not hit the valve seat B12, and the intake air is smoothly introduced into the combustion chamber 34.

However, laser clad valve seats require advanced manufacturing techniques and are expensive to produce. Therefore, there is a demand for a technique that can suppress the obstruction of the flow of intake air due to the valve seat without using the laser clad valve seat.

FIG. 4 is a schematic enlarged view of the intake port 40 in the cylinder head A14 of the third comparative example. The cylinder head A14 of the third comparative example includes the valve seat B14 of the third comparative example. The valve seat B14 has a height H2. Height H2 is lower than height H1 in FIG. The height H2 is, for example, 3 mm or less.

Since the height of the valve seat B14 is low, the amount of protrusion of the valve seat B14 with respect to the inner surface of the intake port 40 is reduced. In FIG. 4, compared with FIG. 2, the protrusion amount of the inner peripheral surface of the upper right portion of the valve seat B14 is reduced. Therefore, the intake air introduced from the intake port 40 into the combustion chamber 34 is less likely to hit the projecting portion of the valve seat B14. As a result, it is possible to prevent the flow of intake air from being obstructed, as indicated by the dashed arrows in FIG. 4 .

However, if the height of the valve seat B14 is lowered, the contact area between the cylinder head A14 and the valve seat B14 decreases when the valve seat B14 is press-fitted into the cylinder head A14. Therefore, the holding force with which the cylinder head A14 holds the valve seat B14 is reduced. As a result, the valve seat B14 may drop out of the cylinder head A14 in some cases. Therefore, in order to increase the holding force of the valve seat by the cylinder head, it is preferable to increase the height of the valve seat.

In contrast to these, FIG. 5 is a schematic enlarged view of the intake port 40 in the cylinder head 24 of this embodiment. The cylinder head 24 of this embodiment includes a valve seat 52a. FIG. 6 is a perspective view of the valve seat 52a according to this embodiment.

The valve seat 52a has a body 70 and an annular projection 74. As shown in FIG. A main body 70 of the valve seat 52a is formed in an annular plate shape. The body 70 of the valve seat 52a has a height H3. The height H3 is approximately the same as the height H2 in FIG. The height H3 is, for example, 3 mm, but is not limited to this example, and may be any value that causes the inner peripheral surface of the valve seat 52a to protrude less.

A main body 70 of the valve seat 52a has a seat surface 72 on which the intake valve 26 can be seated. The seat surface 72 is formed by obliquely cutting the inner peripheral surface of the main body 70 on the side of the combustion chamber 34 . The seat surface 72 is formed in accordance with the canopy shape of the intake valve 26 .

The annular protrusion 74 of the valve seat 52a is formed in an annular shape and arranged on the outer peripheral side of the valve seat 52a. The annular protrusion 74 protrudes in the axial direction of the valve seat 52a, that is, in the height direction of the valve seat 52a. The annular protrusion 74 protrudes from the main body 70 toward the side opposite to the combustion chamber 34 .

An outer peripheral surface 76 of the annular protrusion 74 is continuous with the outer peripheral surface of the main body 70 . The outer diameter of the outer peripheral surface 76 of the annular protrusion 74 is equal to the outer diameter of the outer peripheral surface of the main body 70 . The inner diameter of the inner peripheral surface 78 of the annular protrusion 74 is larger than the inner diameter of the inner peripheral surface of the main body 70 .

The valve seat 52a has a height H4 on the outer peripheral surface side. That is, the height H4 is the height from the combustion chamber 34 side surface of the main body 70 to the tip of the annular projection 74 . Height H4 is at least higher than height H3. The height H4 is approximately the same as the height H1 in FIG. 2, for example. The height H4 is, for example, 6 mm, but is not limited to this example and may be any value higher than the height H3. Also, the amount of projection of the annular projection 74 corresponds to the value obtained by subtracting the height H3 from the height H4.

FIG. 7 is a detailed enlarged sectional view of the opening 44a of the intake port 40 in the cylinder head 24 of this embodiment. FIG. 8 is an internal plan view of the cylinder head 24 viewed from the combustion chamber 34 side. 7 and 8 omit the valve seat 52a and show the state before the valve seat 52a is attached to the attachment portion 50a.

A mounting portion 50 a provided around the opening 44 a has an annular groove 80 . The annular groove 80 is formed in an annular shape and arranged on the outer peripheral side of the mounting portion 50a. The annular groove 80 is recessed on the side opposite to the combustion chamber 34 .

The annular groove 80 is configured to accommodate the annular projection 74 of the valve seat 52a. Specifically, the annular groove 80 has a first inner surface 82 on the outer peripheral side (outer inner wall surface) and a second inner surface 84 on the inner peripheral side (inner inner wall surface). A first inner surface 82 on the outer peripheral side of the annular groove 80 is continuous with the inner surface on the outer peripheral side of the mounting portion 50a. The diameter of the first inner surface 82 of the annular groove 80 is approximately equal to the diameter of the inner surface of the mounting portion 50a. The diameter of the first inner surface 82 of the annular groove 80 is approximately equal to the diameter of the outer peripheral surface 76 of the annular projection 74 . The diameter of the second inner surface 84 on the inner peripheral side of the annular groove 80 is approximately equal to the diameter of the inner peripheral surface 78 of the annular projection 74 . The depth of the annular groove 80 is roughly equal to the amount of protrusion of the annular projection 74 .

The diameter of the second inner surface 84 of the annular groove 80 may be smaller than the diameter of the inner peripheral surface 78 of the annular protrusion 74 . Also, the depth of the annular groove 80 may be greater than the amount of protrusion of the annular projection 74 .

The annular groove 80 is formed such that the central axis of the opening 44a of the intake port 40 and the central axis of the annular groove 80 overlap. For example, in the manufacturing process for forming the opening 44a, along with the formation of the opening 44a, the annular groove 80 may be formed by a tool coaxial with the central axis of the tool forming the opening 44a.

FIG. 9 is a detailed enlarged cross-sectional view of the opening 44a of the intake port 40 with the valve seat 52a attached. The solid line intake valve 26 in FIG. 9 indicates an open state, and the dashed line intake valve 26 in FIG. 9 indicates a closed state.

By press-fitting the valve seat 52a into the mounting portion 50a of the cylinder head 24, the mounting portion 50a and the valve seat 52a are fitted, and the valve seat 52a is mounted on the mounting portion 50a. When the valve seat 52a is attached to the mounting portion 50a, the annular projection 74 of the valve seat 52a is accommodated in the annular groove 80 of the mounting portion 50a, and the annular projection 74 and the annular groove 80 are fitted.

The outer peripheral surface 76 of the annular projection 74 of the valve seat 52a is in contact with the first inner surface 82 of the annular groove 80 on the outer peripheral side when the valve seat 52a is attached to the attachment portion 50a. The outer peripheral surface of the main body 70 of the valve seat 52a is also in contact with the inner surface of the mounting portion 50a.

In the cylinder head 24 of the present embodiment, the outer peripheral surface 76 of the annular projection 74 is in contact with the first inner surface 82 of the annular groove 80. Therefore, the cylinder head 24 and the valve seat 52a are closer together than the third comparative example shown in FIG. contact area can be increased. As a result, the cylinder head 24 of the present embodiment has a greater frictional force between the cylinder head 24 and the valve seat 52a than the third comparative example shown in FIG. Therefore, in the cylinder head 24 of the present embodiment, even if the height of the main body 70 of the valve seat 52a is reduced, the annular projection 74 can suppress a decrease in the holding force of the valve seat 52a by the cylinder head 24. . As a result, in the cylinder head 24 of the present embodiment, the valve seat 52a can be stably fixed to the mounting portion 50a of the cylinder head 24, and the valve seat 52a can be prevented from coming off from the cylinder head 24.

Although not shown, if the outer peripheral surface 76 of the annular protrusion 74 is in contact with the first inner surface 82 of the annular groove 80 when the valve seat 52a is attached to the attachment portion 50a, the inner circumference of the annular protrusion 74 The surface 78 does not have to be in contact with the second inner surface 84 on the inner peripheral side of the annular groove 80 . In this mode as well, the valve seat 52a can be stably fixed to the mounting portion 50a of the cylinder head 24 by the frictional force between the outer peripheral surface 76 of the annular projection 74 and the first inner surface 82 of the annular groove 80.

On the other hand, as shown in FIG. 9, the outer peripheral surface 76 of the annular projection 74 is in contact with the first inner surface 82 of the annular groove 80 when the valve seat 52a is mounted on the mounting portion 50a. The inner peripheral surface 78 is also preferably in contact with the second inner surface 84 of the annular groove 80 . Thus, in addition to the contact between the outer peripheral surface 76 of the annular projection 74 and the first inner surface 82 of the annular groove 80, the inner peripheral surface 78 of the annular projection 74 is also brought into contact with the second inner surface 84 of the annular groove 80. A greater frictional force between the annular groove 80 and the annular protrusion 74 can be achieved. Therefore, in this aspect, the holding force of the valve seat 52a by the cylinder head 24 can be increased, and the valve seat 52a can be fixed to the mounting portion 50a of the cylinder head 24 more stably.

In addition, in the aspect in which both the outer peripheral surface 76 and the inner peripheral surface 78 of the annular projection 74 contact the annular groove 80 , the inner peripheral surface 78 of the annular projection 74 does not contact the annular groove 80 . It is possible to reduce the amount of protrusion. For example, the amount of projection of the annular projection 74 is the sum of the surface area of the outer peripheral surface of the valve seat 52a and the surface area of the inner peripheral surface 78 of the annular projection 74. can be a value that is greater than or equal to the surface area of

In the cylinder head 24 of this embodiment, the height H3 of the main body 70 of the valve seat 52a can be made as low as the height H2 of the third comparative example in FIG. As a result, the cylinder head 24 of the present embodiment can suppress the amount of protrusion of the inner peripheral surface of the main body 70 of the valve seat 52a with respect to the inner surface of the intake port 40, as shown in FIG. Therefore, the cylinder head 24 of the present embodiment can prevent the flow of intake air from being obstructed by the valve seat 52a, as indicated by the dashed arrow in FIG.

FIG. 10 is a diagram showing the relationship between the amount of intake air introduced into the combustion chamber 34 and the strength of the tumble flow of the intake air introduced into the combustion chamber 34. As shown in FIG. A black circle C10 in FIG. 10 indicates the case of the cylinder head A10 of the first comparative example in FIG. A white circle C12 in FIG. 10 indicates the case of the cylinder head 24 of this embodiment.

As shown in FIG. 10, in the cylinder head 24 of the present embodiment, the amount of intake air is increased and the strength of the tumble flow is increased as compared with the cylinder head A10 of the first comparative example. In the cylinder head 24 of this embodiment, the amount of intake air is large, so the intake air is smoothly introduced into the combustion chamber 34 . Further, in the cylinder head 24 of the present embodiment, since the strength of the tumble flow is large, a more suitable tumble flow is formed within the combustion chamber 34 . That is, in the cylinder head 24 of the present embodiment, it is possible to accurately prevent the flow of intake air from being obstructed due to the valve seat 52a.

Therefore, according to the cylinder head 24 of the present embodiment, it is possible to suppress the flow of intake air from being blocked by the valve seat 52a and to suppress the decrease in the holding force of the valve seat 52a by the cylinder head 24. It is possible to

In the above embodiment, the valve seat 52a of the intake port 40 is provided with the annular projection 74. As shown in FIG. However, the valve seat 52 b of the exhaust port 42 may also be provided with the annular protrusion 74 . In this case, the mounting portion 50b of the exhaust port 42 is provided with an annular groove 80 capable of accommodating the annular protrusion 74 of the valve seat 52b. Then, with the valve seat 52b of the exhaust port 42 attached to the attachment portion 50b, the outer peripheral surface 76 of the annular protrusion 74 is brought into contact with the first inner surface 82 of the annular groove 80 on the outer peripheral side.

Although the embodiments of the present invention have been described above with reference to the accompanying drawings, it goes without saying that the present invention is not limited to such embodiments. It is obvious that a person skilled in the art can conceive of various modifications or modifications within the scope of the claims, and it should be understood that these also belong to the technical scope of the present invention. be done.

24 cylinder head 34 combustion chamber 40 intake port 26 intake valve 52a valve seat 44a opening 50a mounting portion 74 annular projection 80 annular groove 76 outer peripheral surface 82 first inner surface 78 inner peripheral surface 84 second inner surface

Claims (3)

an intake port connected to the combustion chamber;
an annular valve seat on which an intake valve that opens and closes the intake port can be seated;
a mounting portion provided around an opening of the intake port on the side of the combustion chamber and to which the valve seat is mounted;
with
The valve seat has an annular protrusion arranged on the outer peripheral side of the valve seat and protruding in the axial direction of the valve seat,
the mounting portion has an annular groove capable of accommodating the annular projection of the valve seat,
The cylinder head, wherein the outer peripheral surface of the annular protrusion is in contact with the first inner surface of the annular groove on the outer peripheral side when the valve seat is attached to the attachment portion. When the valve seat is attached to the attachment portion, the outer peripheral surface of the annular projection is in contact with the first inner surface of the annular groove, and the inner peripheral surface of the annular projection is the inner surface of the annular groove. 2. A cylinder head according to claim 1, in contact with the second inner surface on the circumferential side. 3. The cylinder head according to claim 1, wherein said annular groove is formed such that a central axis of said opening of said intake port and a central axis of said annular groove overlap.

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