JPH09228887A - Internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance cooling property of a valve and a valve seat so as to aim at their strength increase as well as to attempt enlargement of a sucked gas quantity by realizing a diameter increase of the valve or its arrangement near the center of a combustion chamber. SOLUTION: An engine 1 is so constituted as opening/closing a port opened to its combustion chamber 7 at a proper timing by means of a valve so as to carry out necessary gas replacement. In this case, a valve seat on which the valve is to be set is composed of joint type valve seats 8, 9 and also provided with a cooling communication part 40 for communicating at least each one part of the joint type valve seats 8, 9 with the water jacket 31 of a cylinder head 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine having a joint type valve seat.

[0002]

2. Description of the Related Art In a four-cycle engine, for example, an intake port and an exhaust port opening to a combustion chamber are opened and closed by an intake valve and an exhaust valve at appropriate timings to perform a required gas exchange, and an intake port of a cylinder head. Further, a valve seat on which the intake valve and the exhaust valve are to be seated intermittently is generally assembled by press fitting around the opening of the exhaust port.

[0003]

By the way, such a press-fitting type valve seat has a relatively large thickness because it is necessary to secure necessary strength and rigidity, and its height is required because a predetermined press-fitting margin is required. The dimensions are also set relatively large.
Therefore, particularly in a multi-valve engine having a plurality of valves, the distance between the valves becomes large, and there is a limit in increasing the diameter of the valves or arranging the valves near the center of the combustion dome. I could not increase.

On the other hand, in the cylinder head into which the valve seat is press-fitted, thick portions are formed around the openings of the intake port and the exhaust port to ensure the required strength and rigidity of those portions. For this reason, the water jacket formed in the cylinder head is located above the throat portions of the intake port and the exhaust port, and the heat conduction distance between the water jacket and the valve seat becomes long, so that the intake valve and the exhaust valve are exhausted. Since the valves and the valve seats have poor cooling properties, the temperatures thereof are increased, and the strength thereof is lowered.

Further, in forming the valve seat, press-fitting type valve seats are used on both the intake side and the exhaust side, and the size of the valve seat is similar to the valve size including the sectional shape, and one combustion is performed. There were restrictions on the layout within the dome. In particular, in the case of a high-power internal combustion engine, it has not been possible to secure a sufficient valve size due to performance requirements.

Further, in the shape of the cylinder head near the valve seat, the valve shaft center and the port shaft center substantially coincide with each other, and moreover, they exist in a plane orthogonal to the crank shaft.
In the conventional layout, if an attempt is made to increase the port diameter in order to improve the performance, the dimension between the ports becomes small, and the cooling between the valve seats becomes disadvantageous.

The present invention has been made in view of the above problems, and it is possible to increase the intake gas amount by increasing the diameter of the valve or arranging it near the center of the combustion chamber.
It is an object of the present invention to provide an internal combustion engine that can enhance the cooling performance of a valve and a valve seat to increase the strength of these.

[0008]

In order to solve the above-mentioned problems and to achieve the object, the invention according to claim 1 is to open and close a port opening to the combustion chamber by a valve at an appropriate timing to perform a required gas exchange. In the internal combustion engine for carrying out the above, the valve seat on which the valve is to be seated is composed of a joint type valve seat, and a cooling communicating portion for communicating at least a part of the joint type valve seat and a water jacket of the cylinder head is provided. It is characterized by that. By directly transferring heat from at least a part of the joint type valve seat to the cooling water of the water jacket without passing through the cylinder head, it is possible to reduce the heat load on the valve and the joint type valve seat. It is possible to increase the strength and increase the strength.

According to a second aspect of the present invention, the internal combustion engine is characterized in that the cooling communication portion is formed by a casting surface hole which communicates with the water jacket of the cylinder head. A cooling head can be easily formed by forming a cylinder head having a casting surface hole with a mold, and joining the joint type valve seat to this cylinder head.
It is easily formed by utilizing the sealing property of the joint type valve seat.

In the internal combustion engine of the third aspect of the present invention, the cooling communication portion has a hole formed by processing for communicating with the water jacket of the cylinder head, and processing for communicating this hole with the joint type valve seat. Alternatively, it is characterized in that it is formed by a peripheral groove around the joint type valve seat formed by a casting surface. By joining the joint type valve seat to the cylinder head, the cooling communication part can be easily formed around the joint type valve seat, and the cooling communication part is
It is formed by utilizing the sealing property of the joint type valve seat.

According to a fourth aspect of the present invention, in an internal combustion engine in which a port opening to a combustion chamber is opened and closed by an intake valve and an exhaust valve at appropriate timings to perform a required gas exchange, a valve seat on which the intake valve should be seated. Is a joint type valve seat, and the valve seat on which the exhaust valve is to be seated is a press fit type valve seat. By making the valve seat on which the intake valve should be seated a joint type valve seat, a large-diameter valve can be adopted on the intake side, and by changing only the intake to a joint type valve seat, performance specifications can be satisfied. it can. The rigidity of the exhaust side, which has a higher thermal load than the intake side, can be reinforced by the press-fitting type valve seat itself.

In the internal combustion engine of the present invention as defined in claim 5, the inner diameter of the junction type valve seat on which the intake valve is to be seated is set to be equal to or larger than the inner diameter of the press fit type valve seat on which the exhaust valve is seated. What I did is a feature. It is possible to satisfy the performance specifications by making the valve seat on which the intake valve should be seated into a joint type valve seat and adopting a large diameter valve on the intake side.

According to a sixth aspect of the present invention, in an internal combustion engine in which a port opening to the combustion chamber is opened / closed by a valve at appropriate timing to perform a required gas exchange, the valve seat on which the valve is to be seated is a joint type valve seat. In addition, the joint type valve seat is inclined outward at a predetermined angle with respect to the valve axis by directing the port axis of the joint type valve seat toward the bore center. By directing the port axis of the junction valve seat toward the center of the bore, the port diameter can be increased by inclining it to the outside at a predetermined angle with respect to the valve axis, and even if a pair of ports is formed, a space is created between the ports. . Therefore, the shape for passing cooling water can be formed by casting, which is advantageous for cooling between valve seats.

According to a seventh aspect of the present invention, in the internal combustion engine according to the seventh aspect, the port axis of the junction type valve seat on which the pair of intake or exhaust valves should be seated is directed toward the bore center so that the valve axis is outside by a predetermined angle. It is characterized by forming a water jacket between these ports.
Forming the water jacket between the ports enhances the cooling performance of the valve and the junction valve seat, lowers their temperatures, and enhances the strength of the valve and the junction valve seat.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an internal combustion engine of the present invention will be described below with reference to the accompanying drawings.

1 to 4 show a first embodiment of an internal combustion engine, FIG. 1 is a longitudinal sectional view of a cylinder head of the internal combustion engine, FIG. 2 is a sectional view taken along the line II--II of FIG. 1, and FIG. 4 to 11 are views for explaining the joining process of the joining type valve seat, FIG. 12 is an enlarged cross-sectional view of the principal part, and FIG. 13 is another embodiment of the principal part. It is an expanded sectional view.

The internal combustion engine 1 is a four-cycle four-valve engine, which comprises two intake valves 2 and two exhaust valves 3 for each cylinder, formed on a cylinder head 4 made of a lightweight A1 alloy. The two intake ports 5 and the two exhaust ports 6 thus opened and closed are opened and closed at appropriate timings by the intake valve 2 and the exhaust valve 3, respectively, whereby required gas exchange is performed.

A concave combustion dome 4a forming a combustion chamber 7 is formed on the lower surface of the cylinder head 4, and the ignition plug 30 is formed on the cylinder head 4 so as to face the combustion chamber 7.
Are formed. Joint type valve seats 8 and 9 on which the intake valve 2 and the exhaust valve 3 should be seated intermittently are respectively provided around the openings of the intake port 5 and the exhaust port 6 formed in the cylinder head 4 to the combustion chamber 7. It is provided. A water jacket 31 is formed on the cylinder head 4, and the water jacket 31 is formed between and around the intake port 5 and the exhaust port 6.

The intake valve 2 and the exhaust valve 3 are slidably inserted in valve guides 10 and 11, respectively, and these are always biased in the closing direction by valve springs 12 and 13. The intake valve 2 and the exhaust valve 3 are cams 1 that rotate while slidingly contacting the valve lifters 14 and 15.
6 and 17 are driven at appropriate timings.

The joint type valve seats 8 and 9 are coated with, for example, 0.1 to 0.1% of a coating on the surface of a base material formed into a ring shape by a Fe-based sintered material having excellent impact resistance, wear resistance and high temperature strength.
It is formed to have a thickness of 30 μm, and these are bonded to the cylinder head 4 by a resistance thermal bonding method. Cu, which has high thermal conductivity and self-lubricating property, is formed in the pores of the Fe-based sintered material, which is the base material of the joining-type valve seats 8 and 9.
And the like are filled by the infiltration treatment.

By the way, as the material of the coating, between A1 which is the main component of the A1 alloy which is the material of the cylinder head 4 and the element or the main component element of the material, A1 and the element or the main component element of the material are used. A material which forms a eutectic alloy having a melting point lower than that of Cu was selected, and Cu was used in this example. In this embodiment, Cu is formed by electroplating.
Although the above coating is formed, other coatings may be formed by electroless plating or thermal spraying. The melting points of A1 and Cu simple substances are 660 ° C. and 1083 ° C., respectively, while A1-C
The temperature of the eutectic point of the u alloy is the melting point of A1, Cu (660 ° C,
548 ° C., which is lower than
An Al-Cu eutectic alloy having a melting point lower than that of 1, Cu can be formed.

Next, the joining process of the joining type valve seat 8 on the intake side will be described with reference to FIGS. 4 to 9 are half-cut sectional views for explaining the joining process of the joining type valve seat, FIG. 10 is an enlarged detailed view of an A portion of FIG. 5, and FIG. 11 is an enlarged detailed view of an B portion of FIG.

First, as shown in FIG. 4, the joint type valve seat 8 is set in a state in which the protrusion 8d on the outer periphery thereof abuts the protrusion on the peripheral edge of the intake port 5 of the cylinder head 4. At this time, the guide bar 20 for guiding the upper electrode 21 shown in FIG. 5 is inserted and set in the valve guide insertion hole formed in the cylinder head 4 in advance.

Next, as shown in FIG. 5, the upper electrode 21 of the resistance welding machine, which moves up and down along the guide bar 20, is fitted to the inner peripheral tapered surface 8b of the joint type valve seat 8 to form the joint type valve seat 8. Is pressed by the upper electrode 21 with a predetermined force F and is pressed against the cylinder head 4. At this time, the A1 alloy, which is the material of the cylinder head 4, and the Cu, which is the material of the coating film 80, are brought into contact and pressed in the solid state. FIG. 10 shows the state of the contact portion between the joint type valve seat 8 and the cylinder head 4 at this time.

Then, from the pressurized state shown in FIG.
When the joint type valve seat 8 is energized (see FIG. 6), the joint type valve seat 8 moves from the cylinder head 4 to the cylinder head 4.
An electric current flows to the contact area, and the contact area between them and their surroundings are heated. At this time, as a result of the atomic motion activated by the temperature rise, mutual diffusion of Cu and A1 atoms occurs at the contact portion between the two, and the solid phase diffusion layer having the Cu—A1 alloy composition forms the coating 80 of the junction valve seat 8. Between the cylinder head 4 and the cylinder head 4.

When the heating temperature reaches a temperature sufficient to generate the liquid phase of the Cu-A1 alloy, the Cu-A1 alloy begins to melt at the contact portion between the junction type valve seat 8 and the cylinder head 4, and This melting progresses with the lapse of time, and as shown in FIG. 11, the Fe-based sintered material, which is the base material of the junction type valve seat 8, and the cylinder head 4 are in direct contact with each other. At this time, the following things proceed simultaneously.

That is, the A1 alloy material of the cylinder head 4 causes a plastic flow in the direction of the arrow in FIG. 11 at the joint interface with the joint type valve seat 8 to discharge the liquid phase generated by the reaction to the outside, and at the contact interface. The solid-state diffusion of Fe atoms and A1 atoms causes the bonded valve seat 8 to be firmly bonded to the periphery of the intake port 5 of the cylinder head 4.

When the joining type valve seat 8 is firmly joined to the cylinder head 4 by the above mechanism, the power supply is cut off. Then, as shown in FIG. 7, a plastically deformable layer 81 of A1 is formed at the joint interface between the joint type valve seat 8 and the cylinder head 4, and a part where the discharged liquid phase is solidified is formed at the interface end. It

Next, as shown in FIG. 8, the electrode 21 is removed to release the pressure on the joint type valve seat 8, and finally the joint type valve seat 8 is machined to a predetermined position as shown in FIG. When finished into a shape, the joining operation of the joining type valve seat 8 to the cylinder head 4 is completed, and the joining type valve seat 8 is firmly joined and integrated with the peripheral edge of the opening of the intake port 5 of the cylinder head 4. It

Although the joining process of only the intake side joint type valve seat 8 has been described above, the exhaust side joint type valve seat 9 is firmly joined to the cylinder head 4 in the same manner.

By the way, the thickness of the joining type valve seats 8 and 9 joined as described above is very thin (usually 5).
The width and height are very small, but as shown in FIG. 3, the width L10 of the A1 alloy portion of the cylinder head 4 is ensured to have a joining strength and the intake valve 2 has a large diameter. Therefore, the amount of intake gas that passes through the intake valve 2 and is supplied into the cylinder (not shown) can be increased to improve the engine output.

By the way, the cylinder head 4 is formed with a water jacket 31 for flowing cooling water. In this embodiment, the joint type valve seats 8 and 9 are used, and at least one of the joint type valve seats 8 and 9 is used. A cooling communication part 40 is provided that connects the parts 8 a and 9 a with the water jacket 31 of the cylinder head 4. As described above, the thickness of the joint type valve seats 8 and 9 itself is also very small, and further, at least a part of the joint type valve seats 8 and 9 is used for the cylinder head 4
By directly transferring the heat to the cooling water of the water jacket 31 without passing through, it is possible to reduce the heat load on the intake valve 2, the exhaust valve 3, and the junction type valve seats 8, 9.
It is possible to enhance the cooling properties of these and increase the strength.

Further, the cooling communication portion 40 can be formed by a casting surface hole 41 which communicates with the water jacket 31 of the cylinder head 4 as shown in FIG. in this way,
Forming a cylinder head 4 having a casting surface hole 41 with a mold,
By joining the joint type valve seats 8 and 9 so as to close the casting surface hole 41 of the cylinder head 4, the cooling communication portion 40 can be easily formed. Moreover, the casting surface hole 4 of the cooling communication portion 40
1 is easily formed by utilizing the sealing properties of the joint type valve seats 8 and 9.

Further, as shown in FIG. 13, the cooling communication portion 40 has a hole 42 formed by processing for communicating with the water jacket 31 of the cylinder head 4, and the hole 42 and the joint type valve seats 8 and 9. It is formed by the peripheral groove 43 around the joint type valve seat formed by communicating processing or casting surface. The circumferential groove 43 may be formed in a part or the entire circumference of the joint type valve seat. As described above, by joining the joint type valve seats 8 and 9 to the cylinder head 4, the cooling communication portion 40 is formed.
Can be easily formed around 9, and the cooling communication part 40 is
It is formed by utilizing the sealing property of the joint type valve seats 8 and 9.

14 and 15 show a second embodiment of the internal combustion engine, FIG. 14 is a vertical sectional view of a cylinder head of the internal combustion engine, and FIG. 15 is a sectional view taken along line XV-XV of FIG.

The internal combustion engine of the second embodiment has the same structure as that of the first embodiment of FIGS.
The same reference numerals are given and the description is omitted.

In the internal combustion engine 1 of the second embodiment, the valve seat on which the intake valve 2 is to be seated is the joint type valve seat 8, and the valve seat on which the exhaust valve 3 is to be seat is the press fit type valve seat 50. doing. The inner diameter D1 of the joining type valve seat 8 on which the intake valve 2 should be seated,
The exhaust valve 3 is set to be larger than or equal to the inner diameter D2 of the press-fitting type valve seat 50 to be seated, and in this embodiment, the inner diameter D1 of the joining type valve seat 8 is larger than the inner diameter D2 of the press-fitting type valve seat 50. It is set.

In particular, in the high-power internal combustion engine 1, the joint type valve seat 8 is used as the valve seat on which the intake valve 2 is to be seated, so that a large-diameter valve can be adopted on the intake side and only the intake air is joined. By changing to the mold valve seat 8, the performance specifications can be satisfied. The rigidity of the exhaust side, which has a higher thermal load than the intake side, can be reinforced by the press-fitting type valve seat 50 itself.

16 to 18 show a third embodiment of an internal combustion engine, FIG. 16 is a vertical sectional view of a cylinder head of the internal combustion engine, FIG. 17 is a sectional view taken along line XVII-XVII of FIG. 16, and FIG. FIG. 17 is a right side view of FIG. 16.

The internal combustion engine of the second embodiment has the same structure as that of the first embodiment of FIGS.
The same reference numerals are given and the description is omitted.

In the internal combustion engine 1 of the third embodiment, by directing the port axis L1 of the joint type valve seat 9 toward the bore center O, a predetermined angle θ is formed with respect to the valve axis L2 as shown in FIGS. 17 and 18. It is offset to the outside. As shown in FIGS. 16 and 18, the opening of the exhaust port 3 is processed using the throat cutter 70 from the combustion dome 4a side along the port axis L1.

In this way, the exhaust port diameter can be increased by orienting the port axis L1 of the junction type valve seat 9 toward the bore center O and inclining it to the outside by a predetermined angle θ with respect to the valve axis L2. Moreover, even when a pair of exhaust ports 3 are formed, a space is created between the ports, and a shape for passing cooling water can be formed by casting, which is advantageous for cooling between valve seats.

In this embodiment, the water jacket 71 is formed between the exhaust ports 3, and by forming the water jacket 71 between the exhaust ports 3, the cooling performance of the exhaust valve 3 and the joint type valve seat 9 is improved. As a result, these temperatures are lowered and the strength of the exhaust valve 3 and the junction type valve seat 9 is increased.

In this embodiment, the case where the port axis L1 of the joint type valve seat 9 on which the exhaust valve 3 is to be seated is directed to the bore center O has been described.
Similarly, the port axis of the joined valve seat 8 to be seated can also be tilted outward at a predetermined angle with respect to the valve axis so as to be directed toward the bore center O.

[0045]

As is apparent from the above description, claim 1
Since the invention described above transfers heat directly from at least a part of the joint type valve seat to the cooling water of the water jacket without passing through the cylinder head, it is possible to reduce the heat load on the valve and the joint type valve seat. It is possible to enhance the cooling properties of these and increase the strength.

According to the second aspect of the present invention, since the cylinder head having the casting surface hole is formed by the mold and the joining type valve seat is joined to the cylinder head, the cooling communicating portion can be easily formed and the cooling communicating portion can be formed. Can be easily formed by utilizing the sealing property of the bonded valve seat.

According to the third aspect of the present invention, by joining the joint type valve seat to the cylinder head, the cooling communication portion can be easily formed around the joint type valve seat, and the cooling communication portion is formed in the joint type valve seat. It can be formed by utilizing the sealing property.

In the invention according to claim 4, the valve seat on which the intake valve is to be seated is a joint type valve seat,
A large-diameter valve can be adopted on the intake side, and performance specifications can be satisfied by changing only the intake to a joint type valve seat.

According to the fifth aspect of the present invention, the performance specifications can be satisfied by using the joint type valve seat as the valve seat on which the intake valve is to be seated and adopting the large diameter valve on the intake side.

According to the sixth aspect of the present invention, the port axis of the junction type valve seat is directed toward the center of the bore, whereby the port diameter can be increased by inclining the port axis to the outside at a predetermined angle with respect to the valve axis, and the pair of ports can be made larger. Even when formed, a space is created between the ports, and the shape for passing cooling water can be formed by casting, which is advantageous for cooling between valve seats.

According to the seventh aspect of the present invention, by forming a water jacket between the ports, the cooling properties of the valve and the joint type valve seat are enhanced and the temperatures thereof are lowered, so that the strength of the valve and the joint type valve seat is improved. Can be increased.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of a cylinder head showing a first embodiment of an internal combustion engine.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an enlarged view of a joint portion of the joint type valve seat.

FIG. 4 is a diagram illustrating a joining process for joining type valve seats.

FIG. 5 is a diagram illustrating a joining process for joining type valve seats.

FIG. 6 is a diagram illustrating a joining process for joining type valve seats.

FIG. 7 is a diagram illustrating a joining process for joining type valve seats.

FIG. 8 is a diagram illustrating a joining process for joining type valve seats.

FIG. 9 is a diagram illustrating a joining process for joining-type valve seats.

FIG. 10 is an enlarged detailed view of a portion A of FIG.

FIG. 11 is an enlarged detailed view of a B part in FIG.

FIG. 12 is an enlarged sectional view of a main part.

FIG. 13 is an enlarged cross-sectional view of another embodiment of the main part.

FIG. 14 is a vertical sectional view of a cylinder head showing a second embodiment of the internal combustion engine.

15 is a sectional view taken along line XV-XV in FIG.

FIG. 16 is a vertical sectional view of a cylinder head showing a third embodiment of an internal combustion engine.

17 is a sectional view taken along line XVII-XVII in FIG.

FIG. 18 is a right side view of FIG.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Intake Valve 3 Intake Valve 4 Cylinder Head 5 Intake Port 6 Exhaust Port 7 Combustion Chamber 8, 9 Joint Valve Seat 31 Water Jacket 40 Cooling Communication Portion

Claims (7)

[Claims] 1. An internal combustion engine in which a port opening to a combustion chamber is opened / closed by a valve at an appropriate timing to perform a required gas exchange, and a valve seat on which the valve is to be seated is a joint type valve seat. An internal combustion engine, comprising: a cooling communication portion that communicates at least a part of the joined valve seat with a water jacket of a cylinder head. 2. The internal combustion engine according to claim 1, wherein the cooling communication portion is formed by a casting hole that communicates with a water jacket of the cylinder head. 3. The cooling communication portion has a hole formed by a process of communicating with the water jacket of the cylinder head, and the joint formed by a process or a casting surface for communicating the hole with the joint type valve seat. The internal combustion engine according to claim 1, wherein the internal combustion engine is formed by a peripheral groove around the mold valve seat. 4. In an internal combustion engine in which a port opening to a combustion chamber is opened and closed by an intake valve and an exhaust valve at appropriate timings to perform a required gas exchange, a valve seat on which the intake valve should be seated is a joint type valve seat. An internal combustion engine, wherein a valve seat on which the exhaust valve is to be seated is a press-fit type valve seat. 5. The inner diameter of the joining type valve seat on which the intake valve is to be seated is set to be equal to or larger than the inner diameter of the press-fitting type valve seat on which the exhaust valve is seated. Internal combustion engine. 6. In an internal combustion engine in which a port opening to a combustion chamber is opened / closed by a valve at an appropriate timing to perform a required gas exchange, a valve seat on which the valve is to be seated is a joint type valve seat, and An internal combustion engine, wherein the joint type valve seat has a port axis directed toward the center of the bore to be inclined outward at a predetermined angle with respect to the valve axis. 7. A water jacket is provided between the ports by inclining the port axis of the junction type valve seat, on which the pair of intake or exhaust valves are to be seated, toward the center of the bore to incline outward at a predetermined angle. The internal combustion engine according to claim 6, wherein the internal combustion engine is formed.