JP2008248894A - Cooling structure of cylinder head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve cooling effect of respective parts in a cylinder head such as a combustion surface and a valve guide part to avoid high temperature stress responding to increase of output of the cylinder head. <P>SOLUTION: In the cylinder head CH of an internal combustion engine, an inter-exhaust-valve jacket 7, connected with an exhaust gas port side jacket 13, having a shape for enclosing an exhaust gas merging port 11 is formed at or around an exhaust valve guide hole 10 part and a passage 15 for cooling the exhaust gas port is opened in an attaching surface of a bottom surface of the cylinder head CH to a cylinder block. A cylindrical deflector 35 for communicating from the passage 15 for cooling the exhaust gas port to the inter-exhaust-valve jacket 7 is internally provided so that a fluid refrigerant from the cylinder block is directly introduced from the passage 15 for cooling exhaust gas port to the inter-exhaust-valve jacket 7. The deflector 35 is provided to detour to avoid interference with the exhaust gas merging port 11 and an exhaust gas branching port 11a. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a structure for improving the cooling effect of each part inside a cylinder head such as a combustion surface and a valve guide part in order to avoid high thermal stress in response to higher output of the cylinder head.

  Conventionally, in a cylinder head of an internal combustion engine (for example, a diesel engine) cooled by a fluid refrigerant such as cooling water, a flow passage or jacket of the fluid refrigerant such as cooling water is formed by casting, a supply / exhaust valve or a supply / exhaust valve. Integrated so as to wrap around the port and fuel injection valve (in the case of a diesel engine), or to face the combustion surface, which is the surface facing the combustion chamber, among the bottom surface, which is the mounting surface to the cylinder block Forming. Among these, a fluid refrigerant jacket is provided between the air supply valves and around the air supply port, especially around the exhaust valve and the exhaust port that become hot, and the jacket burns to cool the combustion surface with this jacket. It was formed so as to face the surface in parallel.

  In the cylinder head, there is formed a fluid refrigerant flow path through which the fluid refrigerant introduced from the cylinder block is circulated to the fluid refrigerant jacket also serving as the combustion surface cooling formed between the valves. As one embodiment, a cooling structure of a four-valve OHV type diesel engine will be described with reference to FIGS. 1 is a bottom view of the cylinder block CH, FIG. 2 is also a plan sectional view, FIG. 3 is a plan view of a state where a fuel injection valve, a valve operating mechanism, and the like are also attached, and FIG. 4 is a state where a valve arm cover is also attached. FIG. 5 is a side sectional view showing the intake valve structure, FIG. 6 is a side sectional view showing the exhaust valve structure, and FIG. 7 is a sectional view taken along line XX in FIG.

  First, of the bottom surface of the cylinder head CH (attachment surface to the cylinder block), a portion facing the combustion chamber in the cylinder bore fitted in the cylinder block is defined as a combustion surface A as shown in FIG. That is, it is a portion surrounded by bolt holes 16, 16,... For fixing the cylinder liner. Further, in order to introduce the fluid refrigerant from the inside of the cylinder block attached via the bottom surface, the fluid refrigerant introduction port is opened at the bottom surface of the cylinder head CH, and the combustion surface is introduced from the introduction port into the cylinder head. A fluid refrigerant vertical introduction path 1 that is substantially perpendicular to A is formed, and fuel injection is performed from the fluid refrigerant vertical introduction path 1 between the supply valve guide hole 8 and the exhaust valve guide hole 10. A fluid refrigerant lateral introduction passage 2 that is communicated with the valve insertion hole 3 and is substantially parallel to the combustion surface A is formed. From the fuel injection valve insertion hole 3, the air supply valve guide holes 8 and 8 (the air supply branch port 9a) are formed. 9a) An inter-supply valve cooling passage 4 parallel to the combustion surface A is provided in the inter-supply valve jacket 5 which is a fluid refrigerant jacket formed between the exhaust valves guide holes 10 and 10 (exhaust branch port 11a). 11a) Fluid refrigerant jacket formed between And communicates the combustion surface A substantially parallel shape of the exhaust valve between the cooling flow path 6 between the gas valve jacket 7. The intake valve jacket 5 and the exhaust valve jacket 7 have combustion surface cooling surfaces 5a and 7a facing the combustion surface A so as to cool the combustion surface A, as shown in FIG. Have. Further, since the exhaust gas is expanded at a higher temperature than the supply air, a large amount of fluid refrigerant is required. Therefore, as shown in FIG. And the caliber is getting bigger. When the inter-exhaust valve cooling flow path 6 is drilled, as shown in FIG. 2, a conical hole 17 is drilled from the side surface of the cylinder head CH, and the exhaust valve jacket 7 and the fuel injection valve insertion hole 3 are formed. An exhaust valve cooling flow path 6 is drilled in the thick part of the gas pipe, and a cap 18 is applied to the outer opening.

In addition to the above-described jacket 5 between the intake valves and the jacket 7 between the exhaust valves formed as a fluid refrigerant jacket in the range of the combustion surface A in plan view, the range of the combustion surface A as shown in FIG. Outside, a supply air merging port side jacket 12 is formed so as to wrap the air supply port 9, and an exhaust port side jacket 13 is formed so as to wrap the exhaust merging port 11, and each of the fluid refrigerant jackets 12 and 13 is conventionally provided. In order to introduce the fluid refrigerant directly from the cylinder block, as shown in FIG. 2 and FIG. 6, an air supply port cooling flow path 14 and an exhaust port cooling flow path 15 having openings at the bottom surface of the cylinder head CH are respectively provided. Communicate. The fluid refrigerant channels 14 and 15 are shown in FIG. 6 (only the exhaust port cooling channel 15 is disclosed, but the air supply port cooling channel 14 is also the same). 13 and the bottom surface of the cylinder head CH are interposed substantially perpendicular to the bottom surface.
Japanese Patent Application No. 5-33640

  Due to the recent trend toward higher output, the cooling effect around the combustion surface and the exhaust valve is further required. This is because the temperature at the time of partial combustion increases in proportion to the increase in output, and the tendency for stress (high temperature stress) due to a temperature difference with other parts in the cylinder head becomes higher. High-temperature stress causes damage to parts in the cylinder head, leakage of fluid refrigerant (cooling water) and lubricating oil, friction of valves and valve seats, and gas blowout due to gaps between the cylinder block on the combustion surface. In order to suppress this as much as possible, it is a problem to sufficiently cool a portion such as the combustion surface in the cylinder head.

  In this configuration, in the configuration of the fluid refrigerant jacket and the fluid refrigerant flow path in the cylinder head formed as described above, the combustion surface cooling surfaces 5a and 7a of the fluid refrigerant jackets 5 and 7 have fluid refrigerant flow as shown in FIG. It is lower than Roads 4 and 6. In other words, the distances between the fluid refrigerant channels 4 and 6 and the combustion surface A are longer than the distances between the combustion surface cooling surfaces 5a and 7a and the combustion surface A. However, this is because the formation part of the fluid refrigerant channels 4 and 6 is the periphery of the fuel injection valve insertion hole 3, and this peripheral part is inserted into the fuel injection valve insertion hole 3 unless a sufficient thickness is taken. This is because there is a problem in fixing the fuel injection valve. On the other hand, with respect to the fluid refrigerant jackets 5 and 7, the combustion surface cooling surfaces 5a and 7a are brought close to the combustion surface A in order to improve the cooling effect of the combustion surface A.

  However, since the distance from the combustion surface A is different in this way, the main part of the fluid refrigerant flowing into the fluid refrigerant jackets 5 and 7 from the fluid refrigerant flow paths 4 and 6 is different from the combustion surface A. It flows in parallel and flows out to the outlet of the fluid refrigerant jackets 5 and 7. Therefore, the amount of collision of the fluid refrigerant only by passing through the surface against the combustion surface cooling surfaces 5a and 7a in the fluid refrigerant jackets 5 and 7 is small, and therefore introduced into each fluid refrigerant jacket 5 and 7. From the viewpoint of the amount of fluid refrigerant to be produced, a sufficient cooling effect did not appear on the combustion surface cooling surfaces 5a and 7a, and the cooling effect on the combustion surface A was not sufficient. With the recent increase in output, a further cooling effect is required for the combustion surface A. However, depending on the conventional cooling structure of the cylinder head, such a required effect cannot be achieved. It was. That is, the high output particularly increases the temperature of the exhaust gas flowing in the exhaust branch ports 11a and 11a and the exhaust gas merge port 11, and particularly the cooling of the combustion surface cooling surface 7a of the jacket 7 between the exhaust valves has the conventional structure. As a result, the combustion surface A is heated to a high temperature, and the above-described high-temperature stress may be adversely affected.

  2 and FIG. 2 in which substantially perpendicular fluid refrigerant channels 14 and 15 are provided on the bottom surface of the cylinder head CH with respect to the respective fluid refrigerant jackets 12 and 13 formed around the supply and exhaust merging ports 9 and 11. In the structure shown in FIG. 6, since the fluid refrigerant from the cylinder block is directly introduced, the inside of each fluid refrigerant jacket 12 and 13 is sufficiently cooled, and the cooling effect of the combustion surface A and the ports 9 and 11 is apparent. Actually, for example, the fluid refrigerant ejected from the exhaust port cooling flow path 15 into the exhaust port side jacket 13 directly collides with the B portion of FIG. 6, and only the B portion is cooled. Thus, the low temperature of the sufficiently introduced fluid refrigerant is not conducted to the other part in the exhaust port side jacket 13, and between the supply port cooling flow path 14 and the supply port side jacket 12. The same situation Occurs and, therefore, can not be entirely cooled feed gas converging port 9/11, also, the cooling effect of the bottom surface of the cylinder head CH is also not much increased.

  In order to enhance the cooling effect in the exhaust joint port 11 particularly in the exhaust valve jacket 7, the inside of the exhaust valve jacket 7 formed so as to wrap around the exhaust joint port 11 and the exhaust branch ports 11 a and 11 a. It is conceivable to increase the flow rate of the fluid refrigerant or increase the flow rate, but the conventional structure of the jacket 7 between the exhaust valves has a problem that the flow rate and the flow rate are insufficient to obtain a cooling effect sufficient for high output. There is also.

  Further, the exhaust valve guide portion (the exhaust valve guide hole 10) is also a part that becomes particularly high in temperature, and becomes a part of the surrounding fluid refrigerant jacket (the exhaust valve jacket 7 or the exhaust port side jacket 15). However, there has been no such structure in the cylinder head in the past.

  In order to solve the above problems, the present invention uses the following means.

  In claim 1, in the cylinder head (CH) of the internal combustion engine, the exhaust port guide jacket (13) is connected to the exhaust port side jacket (13) around the exhaust valve guide hole (10) or the exhaust valve guide hole (10). An exhaust valve jacket (7) shaped to enclose the exhaust confluence port (11) is formed, and an exhaust port cooling channel (15) is opened on the mounting surface of the bottom surface of the cylinder head (CH) to the cylinder block. From the exhaust port cooling flow path (15), the fluid refrigerant from the cylinder block is directly led from the exhaust port cooling flow path (15) to guide the fluid refrigerant from the cylinder block to the exhaust valve jacket (7). A tubular deflector (35) communicating with the jacket (7) between the exhaust valves is installed in the pipe, and the deflector (35) is detoured so as not to interfere with the exhaust junction port (11) and the exhaust branch port (11a). It is those that were.

  The present invention has the following effects due to the above structure.

  As in claim 1, in the cylinder head (CH) of the internal combustion engine, the exhaust valve guide hole (10) is connected to the exhaust port side jacket (13) around the exhaust valve guide hole (10) or the exhaust valve guide hole (10). An exhaust valve jacket (7) shaped to enclose the exhaust confluence port (11) is formed, and an exhaust port cooling channel (15) is opened on the mounting surface of the bottom surface of the cylinder head (CH) to the cylinder block. From the exhaust port cooling flow path (15), the fluid refrigerant from the cylinder block is directly led from the exhaust port cooling flow path (15) to guide the fluid refrigerant from the cylinder block to the exhaust valve jacket (7). A cylindrical deflector (35) communicating with the jacket (7) between the exhaust valves is internally installed, and the deflector (35) is detoured so as not to interfere with the exhaust junction port (11) and the exhaust branch port (11a). Therefore, the fluid refrigerant introduced directly from the cylinder block is spread throughout the fluid refrigerant jacket, and the whole fluid refrigerant jacket is uniformly cooled, so that the combustion surface, the valve and the valve around the fluid refrigerant jacket in the cylinder head Since the ports and other parts are cooled and the internal combustion engine has a tendency to increase the output, it is possible to supply a highly durable cylinder head that has a high cooling effect on the combustion surface and other valve operating parts and does not generate high-temperature stress. is there.

  In addition, the fluid refrigerant is sent directly from the cylinder block around the valve guide part to enhance the cooling effect of this part, and the valve part and the valve port around the deflector are cooled, resulting in high output of the internal combustion engine. In recent years, the cooling effect of the combustion surface and other valve operating parts is high, and a highly durable cylinder head free from high temperature stress can be supplied.

  Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 8 is a cross-sectional view of the cylinder head CH taken along the line XX in FIG. 1, and is a diagram in the case where the pipe 19 as the combustion surface cooling means according to the present invention is provided in the jacket 7 between the exhaust valves. FIG. 10 shows a case where a deflector 21 is provided, FIG. 11 shows a case where a flow path control plate 7b is provided on the combustion surface cooling surface 7a in the jacket 7 between the exhaust valves. FIG. 12 is a cross-sectional view taken along line YY in FIG. 11, and FIG. 13 is a cylinder head when a flow path control plate 22 projects from the combustion surface cooling surface 7a in the jacket 7 between the exhaust valves. FIG. 14 is a sectional view taken along line YY in FIG. 13, and FIG. 15 is a sectional view taken along line XX in FIG. 1 of the cylinder head CH, and has an exhaust valve having a curved portion 6'a at the outlet portion. A diagram in the case of providing the intercooling flow path 6 ′, 16 is a side sectional view of the cylinder head CH when an inclined exhaust valve cooling passage 6 ″ is provided, and FIG. 17 is an internal fitting of a pipe member 23 having a spiral groove 23a in the fluid refrigerant introduction passages 1 and 2. FIG. 18 is a side sectional view of the cylinder head CH when the fin portion 2 a is formed in the fluid refrigerant lateral introduction path 2, and FIG. 19 is a narrow portion 7 c in the jacket 7 between the exhaust valves. FIG. 20 is a bottom view of the cylinder head CH when the exhaust branch ports 11a and 11a are deformed to form a cylinder. FIG. 20 shows the cylinder head CH when the bend-like fluid refrigerant flow paths 15 and 15a are connected to the exhaust port side jacket 13. FIG. 21 is a cross-sectional view taken along the line ZZ in FIG. 20, and FIG. 22 is a cross-sectional view when the deflector 23 is extended from the fluid refrigerant passage 15 to the exhaust valve guide jacket 7 around the exhaust valve guide hole 8. Plan sectional view of Daheddo CH, FIG. 23 is a Z'-Z 'line cross-sectional view in FIG. 22.

  As an embodiment of the present invention, a one-cylinder head CH of a four-valve OHV type diesel engine is taken up. The internal structure of the cylinder head CH is basically the same as that described in the prior art. That is, as shown in FIG. 1 to FIG. 7, a portion facing the combustion chamber (portion surrounded by the bolt holes 16, 16... In a plan view) is formed on the bottom surface of one cylinder head CH. The fuel injection valve insertion hole 3 is formed substantially at the center of the combustion surface A, and the air supply valve guide holes 8 and 8, the air supply branch ports 9a and 9a, the air supply merging port 9 and the exhaust guide hole are formed around the fuel injection valve insertion hole 3. 10 and 10, exhaust branch ports 11 a and 11 a, and exhaust merge port 11 are formed. Further, as a fluid refrigerant jacket, the combustion surface cooling surface 7 a. An air supply valve jacket 7 and an exhaust valve jacket 9 having 9a are formed. Outside the combustion surface A, an air supply port side jacket 12 and an exhaust port side jacket 13 are formed, and the bottom surface of the cylinder head CH is used as a fluid refrigerant flow path. More burning The fluid refrigerant longitudinal introduction path 1 and the fluid refrigerant lateral introduction path 2 are inserted into the injection valve insertion hole 3, the air supply valve cooling flow path 4 is inserted from the fuel injection valve insertion hole 3 into the air supply valve jacket 5, and the fuel injection valve is inserted. From the hole 3 to the exhaust valve jacket 7, the inter-exhaust valve cooling flow path 6, from the bottom surface of the cylinder head CH to the air supply port side jacket 12, and from the bottom surface of the cylinder head CH to the exhaust port. An exhaust port cooling flow path 15 is formed in the side jacket 13.

  Here, the structure of a fuel injection valve, a valve operating mechanism, and the like attached to the cylinder head CH will be described with reference to FIGS. First, the cylinder head CH is attached to the upper surface of a cylinder block (not shown) and fastened to the cylinder block with mounting bolts 24, 24... Screwed into the bolt holes 16. A combustion chamber is formed inside the surface fastened by the mounting bolts 24, 24,..., And the bottom surface of the cylinder head CH facing this is the combustion surface A. A fuel injection valve 25 is fitted and fixed in the fuel injection valve insertion hole 3 as shown in FIG. 3, and each of the air supply valve 26 and the exhaust valve 27 is inserted into each air supply valve guide hole 8 and each exhaust valve guide hole 10. The valve shaft part is slidably inserted. A valve arm support base 29 is erected on the upper surface of the cylinder head CH via bolts 28 and 28, and an air supply valve arm 30 and an exhaust valve arm 31 are pivotally supported on each side of the valve arm support base 29, respectively. As shown in FIGS. 5 and 6, the upper ends of the two air supply valves 26 and 26 and the exhaust valves 27 and 27 are respectively attached to the one ends of the air supply valve arm 30 and the exhaust valve arm 31, and pushed from the other ends. The rods 32 and 33 extend downward and are pressed against the cam in the cylinder block via a tappet. The fuel injection valve 25 and the valve operating mechanism attached in this way are covered with a valve arm cover 34 attached to the upper surface of the cylinder head CH as shown in FIG.

  As described above, in the internal structure of the 4-valve cylinder head CH having the same fluid refrigerant jacket and fluid refrigerant flow path as those shown in FIGS. A configuration in which various combustion surface cooling means are provided in the jacket 7 between the exhaust ports formed between and around the branch ports 11a and 11a will be described with reference to FIGS. The combustion surface cooling means used in the following configuration examples can also be applied to the inter-supply valve jacket 5, and may be applied to the inter-supply valve jacket 5 when it is desired to improve the cooling effect.

  In the configuration example of FIG. 8, the pipe 19 is fitted from the outer surface of the cylinder head CH, and the inner end thereof is communicated with the opening of the inter-exhaust valve cooling passage 6 with respect to the inter-exhaust valve jacket 7. Pass through the jacket 7 between the exhaust valves. In the through portion of the pipe 19 in the jacket 7 between the exhaust valves, one or a plurality of holes 19a are provided in a portion facing the combustion surface cooling surface 7a. The pipe 19 is preferably a pipe material having heat resistance and corrosion resistance, such as a steel pipe. When the pipe 19 is provided, the pipe 19 is inserted using the conical hole 16. Alternatively, the pipe 19 may be disposed in a predetermined position in the cylinder head CH before casting, and casting may be performed. Further, it is conceivable that another pipe for recovering the fluid refrigerant is connected to the outer end of the pipe 19 from the outside of the cylinder head CH and used for cooling the other part.

  In such a configuration, the fluid refrigerant flowing into the pipe 19 from the inter-exhaust valve cooling flow path 6 is ejected from the hole 19a into the inter-exhaust valve jacket 7, and first collides with the combustion surface cooling surface 7a. Then, the exhaust valve jacket 7 is filled and used for cooling the exhaust valve guide holes 10 and 10, the exhaust branch ports 11 a and 11 a, and the exhaust junction port 11. Accordingly, since the relatively low-temperature fluid refrigerant collides with the combustion surface cooling surface 7a in a substantially vertical direction and directly from the cooling passage 6 between the exhaust valves, the combustion surface cooling surface 7a is sufficiently cooled. The cooling effect of the combustion surface A is improved.

  Next, the combustion surface cooling means shown in FIG. 9 will be described. In the jacket 7 between the exhaust valves, a covering member 20 is disposed so as to cover the combustion surface cooling surface 7a and the wall portion around the fuel injection valve insertion hole 3. In the covering member 20, an outlet of the cooling passage 6 between the exhaust valves is opened, and an outlet 20a is provided in the covering member 20, and the fluid refrigerant in the covering member 20 is It can flow out into the jacket 7 between the exhaust valves outside the covering member 20. The covering member 20 may be a cast material, a steel plate, or the like, and preferably has heat resistance and corrosion resistance. As an arrangement processing method, it is conceivable to arrange at a predetermined position before casting and perform casting.

  In such a configuration, the fluid refrigerant that has flowed into the covering member 11 from the inter-exhaust-valve cooling flow path 6 is first guided by the covering member 20 and collides with the combustion surface cooling surface 7a. The fluid refrigerant flowing out of 20a is filled in the exhaust valve jacket 7 and used for cooling the exhaust valve guide holes 10 and 10 and the exhaust ports 11a, 11a and 11. Accordingly, since the relatively low-temperature fluid refrigerant collides with the combustion surface cooling surface 7a in a substantially vertical direction and directly from the cooling passage 6 between the exhaust valves, the combustion surface cooling surface 7a is sufficiently cooled. The cooling effect of the combustion surface A is improved.

  Further, the combustion surface cooling means shown in FIG. 10 will be described. In the jacket 7 between the exhaust valves, a deflector 21 is piped from the outlet of the cooling passage 6 between the exhaust valves, and the outlet 21a faces the combustion surface cooling surface 7a. The deflector 21 is made of a material having heat resistance and corrosion resistance. As a piping method, it is conceivable that the deflector 21 is disposed at a predetermined position before casting and is cast.

  In such a configuration, the fluid refrigerant that has flowed into the deflector 21 from the inter-exhaust-valve cooling flow path 6 first flows out of the outlet 21a and collides with the combustion surface cooling surface 7a, and then the exhaust-valve jacket. 7 is used to cool the exhaust valve guide holes 10 and 10 and the exhaust ports 11a, 11a and 11. Accordingly, since the relatively low-temperature fluid refrigerant collides with the combustion surface cooling surface 7a in a substantially vertical direction and directly from the cooling passage 6 between the exhaust valves, the combustion surface cooling surface 7a is sufficiently cooled. The cooling effect of the combustion surface A is improved.

  Next, a configuration example of a flow path control plate that protrudes from the combustion surface cooling surface as the combustion surface cooling means will be described with reference to FIGS. 11 and 12, a part of the combustion surface cooling surface 7a protrudes from the combustion surface cooling surface 7a of the jacket 7 between the exhaust valves so as to face the outlet of the cooling passage 6 between the exhaust valves. The formed flow path control plate 7b is disclosed. The flow path control plate 7b is integral with the bottom thick portion of the cylinder head CH between the combustion surface cooling surface 7a and the combustion surface A. This is the same as if the fins were provided on the bottom thick part, and the thermal conductivity from the bottom thick part to the combustion surface A was improved. The fluid refrigerant that has flowed out of the outlet of the inter-exhaust-valve cooling passage 6 directly collides with the passage control plate 7b in a substantially vertical shape, whereby the passage control plate 7b is first cooled. The cooling effect spreads to the integral bottom thick part, and the combustion surface A is sufficiently cooled.

  Further, in FIGS. 13 and 14, the exhaust gas control plate 22, which is a member different from the material of the cylinder head CH, is disposed so as to face the outlet of the inter-exhaust valve cooling flow channel 6 in the same manner as described above. The structure arrange | positioned so that it may protrude from the combustion surface cooling surface 7a of the jacket 7 between valves is disclosed. The flow path control plate 22 is connected to the combustion surface cooling surface 7a, and improves the heat conductivity to the combustion surface cooling surface 7a, the bottom thick portion, and the combustion surface A, and is used for cooling between the exhaust valves. The fluid refrigerant from the outlet of the flow path 6 is cooled by colliding directly and substantially vertically, and the cooling effect is sufficiently spread to the combustion surface A. Here, the flow path control plate 22 which is a separate member from the cylinder head CH is made of, for example, aluminum having high thermal conductivity, and is made of a material having better thermal conductivity than the material of the cylinder head CH. Thus, the thermal conductivity to the combustion surface cooling surface 7a, the bottom thick portion, and the combustion surface A can be further improved.

  With the configuration of the flow path control plate 7b or 22 as described above, the thermal conductivity of the portion C shown in FIGS. 12 and 14 on the combustion surface cooling surface 7a is the heat in the case where the flow path control plate 7b or 22 is not provided. For example, it is about 1.5 times the conductivity.

  Next, a structure for improving the fluid refrigerant flow path will be described with reference to FIGS. 15 and 16 as a structure for cooling the combustion surface A by cooling the combustion surface cooling surface of the fluid refrigerant jacket. 15 and 16 disclose a structure for improving the exhaust valve cooling flow path 6 to cool the combustion surface A by cooling the combustion surface cooling surface 7a of the jacket 7 between the exhaust valves. It is also conceivable to cool the combustion surface cooling surface 5a of the inter-supply valve jacket 5 by applying the following improved configuration to the supply valve cooling flow path 4.

  As a basic idea, if the combustion surface side portion at the outlet end of the inter-exhaust valve cooling passage 6 is connected to the combustion surface cooling surface 7a of the inter-exhaust valve jacket 7, the inside of the inter-exhaust valve cooling passage 6 The fluid refrigerant flowing through the combustion surface cooling surface 7a can be guided onto the combustion surface cooling surface 7a, but the inlet portion of the inter-exhaust valve cooling flow path 6 is a wall around the fuel injection valve insertion hole 3 as described in the prior art. In order to obtain a sufficient thickness between the portion and the combustion surface A, the distance between the combustion surface A and the combustion surface A must be increased to some extent. Therefore, the inlet portion cannot be brought close to the combustion surface A side. Accordingly, the exhaust valve cooling flow path 6 parallel to the combustion surface A shown in FIG. 7 cannot be arranged in parallel with the combustion surface A as it is. Thus, the inter-exhaust-valve cooling flow paths 6 'and 6 "as shown in FIGS. 15 and 16 have been devised.

  First, the exhaust valve cooling flow path 6 ′ shown in FIG. 15 is basically the same as the constant diameter exhaust gas cooling path 6 substantially horizontal to the combustion surface A shown in FIG. Although the distance between the inlet and the combustion surface A is sufficiently maintained, improvements can be seen at the outlet. That is, a curved portion 6 ′ a curved toward the combustion surface A is formed in the combustion surface side portion near the outlet opening in the exhaust valve jacket 7, and the outlet end thereof is the combustion surface cooling surface of the exhaust valve jacket 7. 7a is connected. Thereby, the fluid refrigerant flowing in the cooling passage 6 'between the exhaust valves is guided to the combustion surface cooling surface 7a through the inclined portion 6'a in the vicinity of the outlet of the flow near the combustion surface A, A sufficient low-temperature fluid refrigerant is brought into contact with the combustion surface cooling surface 7a, and the combustion surface A is cooled through this.

  16 is formed by drilling a constant-diameter conical hole in an inclined shape, and the inlet opening to the fuel injection valve insertion hole 3 is illustrated in FIG. 2, the combustion surface side portion of the outlet end thereof is connected to the combustion surface cooling surface 7a of the inter-exhaust valve jacket 7. Thus, the exhaust valve is located in the same position as the exhaust valve cooling flow path 6 shown in FIG. The fluid refrigerant flowing in the intercooling flow path 6 "is guided to the combustion surface cooling surface 7a in the vicinity of the outlet of the fluid refrigerant near the combustion surface A, and a sufficient low temperature fluid refrigerant is brought into contact with the combustion surface cooling surface 7a. Through this, the combustion surface A is cooled.

  Among these, in the case of the configuration example of the inter-exhaust valve cooling flow path 6 ″, the thermal conductivity of the D portion of the combustion surface cooling surface 7a shown in FIG. If the thermal conductivity at the same position in the case of being formed is 1, for example, the thermal conductivity is approximately doubled, and by having such a high thermal conductivity, the cooling effect of the combustion surface cooling surface 7a is sufficiently high. This causes a sufficient cooling effect on the combustion surface A.

  Next, a configuration for improving the cooling effect between the valves and the combustion surface A by improving the fluid refrigerant lateral introduction path 2 shown in FIGS. 1 and 2 will be described with reference to FIGS. 17 and 18. Basically, the inner surface of the fluid refrigerant lateral introduction path 2 is finned to improve heat exchange. However, in the configuration example shown in FIG. 17, an L-shape having a spiral groove 23a formed on the inner peripheral surface. A bent tube member 23 is internally fitted over the longitudinal channel 1 for introducing fluid refrigerant and the transverse channel 2 for introducing fluid refrigerant. This piping method is a casting process for piping before casting, and the material of the pipe member may be a metal material or the like that has heat resistance and corrosion resistance.

  On the other hand, in the configuration example shown in FIG. 18, the fin portions 2 a, 2 a... Are integrally formed on the inner peripheral surface of the fluid refrigerant introduction lateral flow path 2 formed integrally with the cylinder head CH. That is, the fins 2a, 2a,... Are formed by a mold, and these are formed by casting.

  With the configuration as shown in FIG. 17 or 18, the cooling effect of the thick portion of the cylinder head CH around the small flow path 2 for introducing the fluid refrigerant is enhanced, and the cooling effect is spread to the combustion surface A and the like. When combined with the combustion surface cooling means in the jacket 7 between the exhaust valves and the improved configuration of the cooling passage 6 between the exhaust valves, a further cooling effect can be seen.

  Next, a configuration example in which the flow rate of the fluid refrigerant is increased by the deformation of the exhaust valve jacket 7 to improve the thermal conductivity will be described with reference to FIG. The exhaust branch ports 11a and 11a on both sides sandwiching the exhaust valve jacket 7 project toward the exhaust valve jacket 7 as shown in FIG. 19, and the passage between the exhaust branch ports 11a and 11a, that is, the exhaust valve jacket 7 The fluid refrigerant passage is narrowed to form a narrow portion 7c. Thereby, when passing through the narrow portion 7c of the jacket 7 between the exhaust valves, the flow rate of the fluid refrigerant is increased, the thermal conductivity of the inner surface of the jacket 7 between the exhaust valves is improved, the cooling effect of the combustion surface A, and the exhaust valve The cooling effect of the exhaust branch ports 11a and 11a in contact with the intermediate jacket 7, the exhaust junction port 11, and the exhaust valve guide holes 10 and 10 is also improved.

  Next, a configuration example in which the fluid refrigerant from the cylinder block is directly introduced into the exhaust port side jacket 13 will be described with reference to FIGS. 20 and 21. FIG. As described in the above prior art, as shown in FIG. 6, a structure in which the exhaust port cooling flow path 15 substantially perpendicular to the bottom surface of the cylinder head CH is directly connected to the exhaust port side jacket 13 is conventionally employed. However, in order to solve the problems of the conventional structure, a bend shape bent into a substantially L shape as shown in FIG. 21 is formed, and the latter half portion of the flow path is a bent portion 15a substantially parallel to the bottom surface of the cylinder head CH. On the other hand, the exhaust port side jacket 13 is formed with a connection surface 13a perpendicular to the bottom surface of the cylinder head CH as a connection surface to the bent portion 15a, and the bent portion 15a parallel to the bottom surface is formed on the connection surface 13a. Are connected so that the fluid refrigerant is introduced into the exhaust port side jacket 13 in parallel with the cylinder head CH. As a result, the fluid refrigerant from the exhaust port cooling passages 15 and 15a is not concentrated in one place in the exhaust port side jacket 13 but spreads throughout. In addition, the air supply port cooling flow path 14 is bent in the same manner as shown in FIG. 20 so that the rear half of the air supply port cooling flow path 14 becomes a bent portion 14a substantially parallel to the bottom surface of the cylinder head CH. The air port side jacket 12 is formed with a connecting surface 12a substantially perpendicular to the bottom surface of the cylinder head CH, and fluid refrigerant is supplied into the air port side jacket 12 via the air port cooling passages 14 and 14a. The cylinder head CH is introduced substantially parallel to the bottom surface of the cylinder head CH.

  Thus, if the thermal conductivity of the B portion in FIG. 8 described in the prior art is 1, the thermal conductivity of the B portion of the exhaust port side jacket 13 in the configuration example of FIGS. For example, about 0.3. At first glance, it seems that the former has higher thermal conductivity and higher cooling effect than the latter, but in the former case, the heat conduction efficiency of the exhaust port side jacket 13 is as much as the heat conduction is concentrated in one part of the B portion. In contrast, in the case of the latter configuration example shown in FIGS. 20 and 21, the thermal conductivity of the B portion is smaller than that of the conventional one, but the heat of the other portion of the exhaust port side jacket 13 is correspondingly reduced. The conductivity is evenly increased. Thus, by improving the thermal conductivity of the exhaust port side jacket 13 as a whole, the entire surface in contact with the exhaust port side jacket 13, that is, the entire bottom surface of the exhaust merging port 11 and the cylinder head CH is cooled, and the cooling effect is enhanced. .

  In the embodiment shown in FIGS. 22 and 23, the fluid refrigerant from the cylinder block is directly fed to the fluid refrigerant jacket 7 around the exhaust valve guide hole 10 (this part is a part of the exhaust valve jacket 7 and is connected to the exhaust joint). In order to guide the exhaust port to the exhaust port side jacket 13 that encloses the port 13), a deflector 35 is piped from the exhaust port cooling flow path 15, and the outlet thereof is a fluid refrigerant jacket around the exhaust valve guide hole 10. 7c. The deflector 35 is detoured so as not to interfere with the exhaust merge port 11 and the exhaust branch port 11a. Thereby, since the fluid refrigerant from the low-temperature cylinder block is directly introduced around the exhaust valve guide hole 10, the cooling effect of the exhaust valve is enhanced and the durability of the exhaust valve is improved. Further, the proximity of the exhaust port 11 to the deflector 35 contributes to cooling of the exhaust port 11 and other parts.

It is a bottom view of cylinder block CH. It is a plane sectional view similarly. It is a top view of the state which attached the fuel injection valve, the valve operating mechanism, etc. similarly. It is a top view of the state where the valve arm cover was similarly attached. It is side surface sectional drawing which similarly shows an air supply valve structure. It is side surface sectional drawing which similarly shows an exhaust valve structure. It is the XX sectional view taken on the line in FIG. FIG. 2 is a cross-sectional view of the cylinder head CH taken along the line XX in FIG. 1 and shows a case where a pipe 19 which is a combustion surface cooling means according to the present invention is provided in the exhaust valve jacket 7. It is a figure at the time of providing the covering member 20 similarly. It is a figure at the time of providing the deflector 21 similarly. FIG. 6 is a plan sectional view of a cylinder head CH when a flow path control plate 7b is projected from a combustion surface cooling surface 7a in an exhaust valve jacket 7. It is the YY sectional view taken on the line in FIG. FIG. 6 is a plan sectional view of a cylinder head CH when a flow path control plate 22 protrudes from a combustion surface cooling surface 7a in an exhaust valve jacket 7. It is the YY sectional view taken on the line in FIG. FIG. 2 is a cross-sectional view of the cylinder head CH taken along the line XX in FIG. It is side surface sectional drawing of cylinder head CH at the time of providing the inclined flow path 6 "between exhaust valve cooling. It is side surface sectional drawing of the cylinder head CH at the time of fitting the pipe member 23 which incorporates the spiral groove 23a in the fluid refrigerant introduction path 1 * 2. 3 is a side cross-sectional view of a cylinder head CH when a fin portion 2a is formed in a fluid refrigerant lateral introduction path 2. FIG. FIG. 5 is a bottom view of the cylinder head CH when the exhaust branch ports 11a and 11a are deformed so as to form a narrow portion 7c in the exhaust valve jacket 7; FIG. 3 is a plan sectional view of a cylinder head CH when a bend-like fluid refrigerant flow path 15, 15 a is connected to the exhaust port side jacket 13. FIG. 21 is a sectional view taken along line ZZ in FIG. 20. FIG. 5 is a plan sectional view of the cylinder head CH when a deflector 23 is extended from the fluid refrigerant flow path 15 of the present invention to the exhaust valve jacket 7 around the exhaust valve guide hole 8. FIG. 23 is a sectional view taken along line Z′-Z ′ in FIG. 22.

Explanation of symbols

CH Cylinder Head A Combustion Surface 1 Fluid Refrigerant Vertical Introductory Path 2 Fluid Refrigerant Lateral Introductory Path 2a Fin Port 3 Fuel Injection Valve Insertion Hole 4 Cooling Channel between Supply Valves 5 Inter-Supply Valve Jacket 5a Combustion Surface Cooling Surface 6 Exhaust Valve Intercooling channel 6 'Exhaust valve cooling channel 6'a Curved portion 6 "Inclined exhaust valve cooling channel 7 Exhaust valve jacket 7a Combustion surface cooling surface 7b Channel control plate 7c Narrow part 8 Supply Air valve guide hole 9 Supply air merge port 9a Supply air branch port 10 Exhaust valve guide hole 11 Exhaust merge port 11a Exhaust branch port 12 Supply port side jacket 13 Exhaust port side jacket 14 Supply port cooling flow path 15 Exhaust port cooling Flow path 19 Pipe (combustion surface cooling means)
19a hole 20 coating member (combustion surface cooling means)
21 Deflector (combustion surface cooling means)
22 Flow path control plate 23 Pipe member 23a Spiral groove 35 Deflector

Claims (1)

In the cylinder head (CH) of the internal combustion engine, connected to the exhaust port side jacket (13) around the exhaust valve guide hole (10) or the exhaust valve guide hole (10), and the exhaust merge port (11) ) To form a jacket (7) between the exhaust valves,
An exhaust port cooling flow path (15) is opened in a mounting surface of the bottom surface of the cylinder head (CH) to the cylinder block, and fluid refrigerant from the cylinder block is supplied from the exhaust port cooling flow path (15). In order to directly lead to the exhaust valve jacket (7), a cylindrical deflector (35) communicating from the exhaust port cooling flow path (15) to the exhaust valve jacket (7) is internally installed. ,
The cooling structure of a cylinder head, wherein the deflector (35) is detoured so as not to interfere with the exhaust merging port (11) and the exhaust branch port (11a).

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