JP3758567B2 - Cylinder head cooling water passage structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cooling water passage structure for a cylinder head with improved cooling performance.
[0002]
[Prior art]
The bottom surface temperature of the cylinder head is one of the main characteristic values that dominate the durability life. Lowering the bottom surface temperature of the cylinder head is important for ensuring durability quality. To that end, it is necessary to secure a sufficient coolant flow velocity near the bottom surface of the coolant passage formed inside, particularly between the ports. is there. On the other hand, if the cooling water flow rate becomes excessive, there are problems such as cavitation and increased pressure loss. Therefore, it is necessary to properly control the cooling water flow rate in each part of the cooling water passage. It is also important to reduce the variation in flow rate between cylinders.
[0003]
FIG. 5 shows a cooling water passage structure of a cylinder head 100 that has been generally employed. In the figure, 101 and 102 are exhaust ports, 103 and 104 are intake ports, and 105 is a fuel injector mounting portion. The longitudinal direction (left and right in the figure) corresponds to each cylinder on the cylinder block (not shown) side. The exhaust ports 101 and 102, the intake ports 103 and 104, and the fuel injector mounting portion 105 are provided along the direction). In the cooling water passage 106, gasket holes 107a, 107b, 107c, and 107d are provided as cooling water inlets corresponding to the respective cylinders. The cooling water flowing in from these inflow ports flows from between the two exhaust ports 101 and 102 around the mounting portion 105 in each cylinder, and flows from the upstream to the downstream as indicated by a small arrow c as a whole. ing. In order to reduce the variation between the cylinders in the flow velocity of the coolant flowing between the exhaust ports 101 and 102, the opening area of the gasket holes 107a, 107b,... It is common to make adjustments such as making it smaller as you go to the right).
[0004]
[Problems to be solved by the invention]
As described above, reducing the variation in the flow rate of the cooling water between the cylinders is important in terms of the durability of the cylinder head. For this reason, the exhaust ports 101 and 102 are adjusted by adjusting the opening areas of the gasket holes 107a to 107d. Although the flow rate variation between the exhaust port 101 and the intake port 103 is different from the amount of cooling water flowing between the exhaust port 102 and the intake port 104, there is a difference in cooling performance. End up. Further, since the cooling water from the cylinder block side flows into each cylinder, the amount of cooling water increases as it goes downstream, and the flow velocity between the exhaust ports 101 and 102 and the intake ports 103 and 104 becomes faster as it goes downstream. Therefore, there is a problem that the cooling capacity between the cylinders also varies.
[0005]
The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide a cooling water passage structure for a cylinder head in which variations in the flow velocity of the cooling water flowing between the ports are reduced.
[0006]
[Means for Solving the Problems]
In the cooling water passage structure of the cylinder head according to the present invention that achieves the above object, the invention according to claim 1 is characterized in that a plurality of cooling water passages are formed in the cylinder head separately. Of these, at least one cooling water passage is connected to at least one cooling water inlet for each cylinder, an inter-port passage through which cooling water flowing in from the inlet flows, and another cooling water passage between the ports. In the cooling water passage structure of the cylinder head provided with a cooling water outlet for allowing the cooling water flowing through the flow passage to flow into other cooling water passages, the inter-port flow passage is divided into two branch passages, which are different from each other. It is configured to flow out to another cooling water passage through the outlet, and the two branch channels are composed of a branch channel directed to the downstream side and a branch channel directed to the upstream side. Channel cross-sectional area is above Characterized in that are smaller than the minimum flow path cross-sectional area of the branch passage side.
[0007]
The invention according to claim 2 is the invention according to claim 1, wherein SL is the minimum channel cross-sectional area of the shunt channel toward the downstream side in the two shunt channels, and SL is the minimum channel cross-sectional area of the shunt channel toward the upstream side. As the SU, the SL / SU ratio in the flow path between ports in the downstream cylinder is equal to or smaller than the SL / SU ratio in the flow path between ports in the upstream cylinder .
[0008]
According to a third aspect of the present invention, a plurality of cooling water passages are separately formed in the cylinder head, and at least one cooling water passage is provided in at least one of the plurality of cooling water passages for each cylinder. Cooling water flow that causes the cooling water flowing through the inter-port passage by communicating with the water inlet, the inter-port passage through which the cooling water flowing in from the inlet flows, and the other cooling water passage. In the cooling water passage structure of the cylinder head provided with an outlet, the inter-port passage is divided into two branch passages, and flows out to other cooling passages through different outlets. , Where SL is the minimum channel cross-sectional area of the diversion channel going downstream in the two diversion channels, and SU is the minimum channel cross-sectional area of the diversion channel going upstream, and SL in the inter-port flow channel in the upstream cylinder / For SU ratio SL / SU ratio of the port between the flow path in the flow-side cylinder, so as to be smaller between at least a portion of the upstream and downstream cylinders, characterized in that it is equal to or smaller.
[0009]
The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the cylinder head is provided with two intake ports and two exhaust ports for each cylinder, and the inter-port flow path. Is characterized in that the cooling water passes between the two exhaust ports and is divided so as to flow between the exhaust ports and the intake ports .
[0010]
The invention according to claim 5 is the invention according to claim 4 , wherein the cooling water inlet is provided in the vicinity of two exhaust ports .
[0011]
The invention according to claim 6 is the invention according to any one of claims 1 to 5 , wherein the outlet of the diversion channel going to the downstream side and the outflow port of the diversion channel going to the upstream side are independently formed for each cylinder. The opening surface of the outlet forms a part of the channel cross section of the branch channel .
[0012]
The invention according to claim 7 is the invention according to any one of claims 1 to 6, wherein the other cooling water passage to which the outflow port communicates has a cross-sectional area corresponding to each cylinder on the upstream side. In comparison, the downstream side is equal or larger .
[0013]
The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the plurality of cooling water passages are formed separately in two upper and lower stages of an upper cooling water passage and a lower cooling water passage. Features .
[0016]
That is, according to the first aspect of the present invention, the inter-port flow path is divided into two branch flow paths, and flows out to the other cooling water passages through different outlets. Therefore, the flow rate can be easily controlled to reduce the difference in cooling capacity between adjacent ports. In addition, the cooling water that has flowed through the branch flow path for each cylinder flows out to the other cooling water passages, and the port wall is rationally cooled to increase the cooling efficiency. Can be avoided. Also, the flow rate of the cooling water flowing between the ports can be changed by adjusting the flow area of the branch flow path, the opening area of the outlet, and the flow area of other cooling water passages communicating with the outlet. Since it can change individually in more detail, it is possible to set the appropriate flow rate and eliminate the variation surely.
Since the minimum channel cross-sectional area of the downstream shunt is smaller than the minimum channel cross-sectional area of the upstream shunt, the flow resistance at the upstream shunt that is relatively difficult to flow is relatively It is possible to make the flow rate in the branch channel directed to the upstream side and the flow rate in the branch channel directed to the downstream side as uniform as possible, and to equalize the cooling ability between the ports. Note that the minimum channel cross-sectional area may be obtained by a branch channel, or the opening area of the outlet may be the minimum channel cross-sectional area.
[0017]
According to the fourth aspect of the present invention, since the cooling water that has passed between the two exhaust ports is diverted so as to flow between each exhaust port and the intake port, adjacent exhaust ports and intake ports are cooled as evenly as possible. Make it possible. Further, in each cylinder, an exhaust port that is relatively high in temperature can be efficiently cooled.
[0018]
According to the invention of claim 5 , the cooling efficiency of the exhaust port can be further increased.
[0022]
As described above, in the other cooling water passages, the cooling water flows from the upstream to the downstream, so there is a pressure difference in the cylinder, and the amount of cooling water increases further on the downstream side. growing. As a result, in the branch path toward the upstream side, the cooling water is less likely to flow toward the downstream side. According to the invention of claim 2 or 3 , since the SL / SU ratio between the cylinders can be made smaller toward the downstream side, the above-mentioned problem can be solved by relatively reducing the flow resistance in the branch flow path toward the upstream toward the downstream side. This eliminates the variation between cylinders.
[0023]
According to the seventh aspect of the present invention, the flow passage cross-sectional area can be increased toward the downstream side in another cooling water passage in which the cooling water flow increases toward the downstream side. Therefore, the phenomenon that the pressure difference in the cylinder increases toward the downstream side can be alleviated.
[0024]
According to the eighth aspect of the present invention, the plurality of cooling water passages are formed separately in two upper and lower stages of the upper cooling water passage and the lower cooling water passage. Can be cooled.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0026]
1 and 2 show a cylinder head 10 of the first embodiment. This cylinder head 10 has an upper cooling water passage 11 and a lower cooling water passage 12 provided in two upper and lower stages. FIG. 1 shows a portion of the lower cooling water passage 12 in a cross section, and FIG. A longitudinal section in the longitudinal direction at the center position of the cylinder is shown. As clearly shown in FIG. 2, regarding the flow of the cooling water, here, the left side of FIG. 2 is the upstream side and the right side is the downstream side.
[0027]
The cylinder head 10 is provided with two exhaust ports 21 and 22 and two intake ports 23 and 24 around the fuel injector mounting portion 25 corresponding to each cylinder.
[0028]
In the cooling water passage 12, gasket holes 15 a, 15 b, 15 c and 15 d are provided in the lower wall 16 of the cylinder head 10 as inlets of cooling water from the cylinder block (not shown) side, corresponding to each cylinder. Is provided. The gasket holes 15a, 15b, 15c and 15d are provided at positions near the outside between the exhaust ports 21 and 22 corresponding to each cylinder. And the opening area of each gasket hole 15a, 15b, 15c, 15d is made small toward the downstream.
Corresponding to the position between the cylinders, an outlet 14 through which cooling water flows out from the lower cooling water passage 12 to the upper cooling water passage 11 is formed in the partition wall 13 of the upper cooling water passage 11 and the lower cooling water passage 12. It is formed and both passages are connected.
[0029]
According to the cooling water passage structure of the cylinder head 10 configured as described above, the flow of the cooling water in the lower cooling water passage 12 can be indicated by the small arrows a and b shown in the drawing. That is, in each cylinder, the cooling water flows into the lower cooling water passage 12 using the corresponding gasket holes 15a, 15b, 15c, 15d as inflow ports, and flows between the ports formed between the exhaust ports 21, 22. After flowing into the passage 31, it flows as shown by a small arrow “a” in a branch passage 32 formed between one (downstream) exhaust port 21 and the intake port 23, and the other (upstream) exhaust port 22 and intake air. As shown by the small arrow b, the flow is divided into the branch flow path 33 formed between the ports 24. Of the divided cooling water, the cooling water having the flow indicated by the small arrow a flows through the downstream outlet 14 to the upper cooling water passage 11, and the cooling water having the flow indicated by the small arrow b is upstream. It flows to the upper cooling water passage 11 through the outlet 14 on the side.
[0030]
As described above, in the lower cooling water passage 12 of each cylinder, the cooling water that has cooled the port wall flows through the lower cooling water passage 12 to the downstream side without flowing to the downstream cylinder side. Therefore, it is possible to appropriately secure the cooling water flowing through the inter-port flow path 31 and the branch flow paths 32 and 33 to rationally cool the port wall of each cylinder, thereby increasing the cooling efficiency. In particular, in the case of this embodiment, the exhaust port that is likely to become high temperature is efficiently cooled, which is effective in improving the durability quality of the cylinder head 10.
[0031]
A point to be noted in the cylinder head 10 of this embodiment is a point of the in-cylinder pressure difference ΔP generated by the flow of the cooling water in the upper cooling water passage 11. Further, in the upper cooling water passage 11, the amount of cooling water increases as it goes downstream due to the cooling water flowing from the cooling water passage 12, and the downstream cylinder pressure difference ΔPL is closer to the downstream side than the upstream cylinder pressure difference ΔPU. It is a point that becomes larger. If the in-cylinder pressure difference ΔP is large, the cooling water indicated by the small arrow b that has been diverted to the diversion channel 33 will not easily flow to the upper cooling water passage 11 through the outflow port 14. As a technique for solving such points to be noted, the following form is taken .
[0033]
In this embodiment , in the lower cooling water passage 12, the area of the branch passage formed between the exhaust port 21 and the intake port 23 is different from the area of the branch passage formed between the exhaust port 22 and the intake port 24. There is a feature in the point. As shown in the figure, the height direction dimension dL1 of the branch flow path 321 on the downstream side with respect to the inter-port flow path 31 is made smaller than the height direction dimension dU1 of the branch flow path 331 on the upstream side, The minimum channel cross-sectional area of the branch channel 321 is made narrower than the channel cross-sectional area of the branch channel 331. The same relationship applies to the other cylinders.
[0034]
By doing so, the flow of the cooling water flowing toward the downstream side as indicated by the small arrow a in the diversion channel 321 can be reduced, and as a result, the amount of cooling water flowing in the diversion channel 331 as indicated by the small arrow b is increased. The problem of the difference in flow rate between the ports due to the cylinder pressure difference ΔP can be eliminated. Therefore, the height dimensions dL1 and dU1 are adjusted to appropriately control the flow rate of the cooling water flowing through the branch flow paths 321 and 331, thereby eliminating variations and efficiently cooling the port wall and the lower wall 16. is there. Similar effects can be obtained in other cylinders having the same relationship.
The above relationship can be applied to the shunt flow in all cylinders, but may be applied to the shunt flow in some cylinders.
[0035]
In this embodiment, the minimum cross-sectional area of the branch flow path between the cylinders is adjusted in order to eliminate the variation between the cylinders. That is, the dL1 / dU1 ratio in the downstream cylinder is smaller than the dL0 / dU0 ratio in one cylinder. This relationship can be obtained by adjusting the minimum cross-sectional area of the diversion channel going to the downstream side and the diversion channel going to the upstream side. Usually, from the viewpoint of ease of design, the downstream side is usually more downstream. The above relationship is obtained by reducing the minimum cross-sectional area of the diverting flow path. In this embodiment, dU0 and dU1 have the same size, and the above relationship is obtained by dL0> dL1.
[0036]
According to the above, even in the cylinder head in which the pressure difference in the cylinder that becomes larger toward the downstream side (ΔP _U <ΔP _{L in the} figure) becomes larger, it is possible to eliminate the difficulty of the water flow in the branch flow path toward the upstream toward the downstream side. Reduce variation in cooling capacity between cylinders.
The above relationship may be applied sequentially among all the cylinders, or the above relationship may be satisfied among some cylinders. For example, the above relationship may be satisfied by limiting only between the downstream cylinders where the problem of in-cylinder pressure difference becomes large.
[0037]
In the above embodiment, the adjusting flow path resistance in the magnitude of the flow path cross-sectional area of the flow path, outlet port in communication with the lower cooling water passage 12 and the upper cooling water passage 11, the outlet shown in FIG. 4 When the upstream branch flow path and the downstream branch flow path are formed independently of each other as well as between the cylinders as in 14a and 14b, these opening areas can be changed without changing the flow path cross-sectional area of the branch flow path. By changing the above, it is possible to obtain the same effect as the adjustment of the channel cross-sectional area of the branch channel.
Further, in this embodiment, the relationship between the flow path cross-sectional area of the shunt flow path toward the downstream side in one cylinder and the flow path cross-sectional area of the shunt flow path toward the upstream side is adjusted, and the relationship between the two for each cylinder. However, the present invention may have only the former configuration. However, in order to eliminate the variation between the cylinders, it is desirable to have both configurations.
[0038]
FIG. 3 shows the cylinder head 10 of the second embodiment, and the same reference numerals are given to the same parts as those of the first embodiment, and the description thereof is omitted.
[0039]
In the second embodiment, the flow area of the upper cooling water passage 11 is changed on the upstream side and the downstream side, and the downstream cross-sectional area is made larger than that on the upstream side. As shown in the figure, the height direction dimension D1 of the upper cooling water passage 11 of the downstream cylinder position is larger than the height direction dimension D0 of the upper cooling water passage 11 of the upstream cylinder position. is there.
[0040]
In this way, the phenomenon that the in-cylinder pressure difference ΔP increases toward the downstream side can be mitigated, and as a result, the cooling in the branch flow path 33 that becomes difficult to flow toward the downstream side due to the in-cylinder pressure difference ΔP. It is possible to facilitate the flow of water (small arrow b). Therefore, it is possible to appropriately control the flow rate of the cooling water flowing through the branch flow paths 32 and 33 to eliminate the variation between the cylinders, and to cool the port wall and the lower wall 16 efficiently. In the present invention, the adjustment of the upper-side channel cross-sectional area may be performed without adjusting the lower-side channel cross-sectional area shown in the first embodiment. Side, upper stage side) may be adjusted.
[0041]
Further, in the description of the second embodiment, although by varying the flow path cross-sectional area by changing the height of the flow path between the fuel injector attachment 25 adjacent, as shown in FIG. 4, the other flow It is also possible to change the cross-sectional area of the upstream and downstream channels by changing the cross-sectional area in the path.
For example, the channel section 180a and the channel section 181a, the channel section 180b and the channel section 181b, the channel section 180c and the channel section 181c, the channel section 180d and the channel section 181d, the channel section 180e and the channel section. A similar effect can be obtained by increasing the cross-sectional area toward the downstream side in the relationship between the flow path cross section 181e and the flow path cross section 181f.
[0042]
As mentioned above, although several embodiment was described, in any embodiment, the flow of a suitable cooling water can be formed between ports for every cylinder in the lower-stage cooling water passage 12. In order to form this proper flow, the cylinder head can be effectively cooled without providing a partition wall, and an increase in the weight of the cylinder head due to the formation of the partition wall can be avoided.
[0043]
【The invention's effect】
As described above, according to the cooling water passage structure of the cylinder head of the present invention, an appropriate flow of cooling water can be ensured between the exhaust port and the intake port. There is an effect of improving the durability of the head.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a lower cooling water passage of a cylinder head according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view along the longitudinal direction.
FIG. 3 is a longitudinal sectional view along the longitudinal direction of a cylinder head according to a second embodiment of the present invention.
FIG. 4 is a cross-sectional view of an upper cooling water passage showing a modification of the second embodiment of the present invention.
FIG. 5 is a cross-sectional view of a cooling water passage of a conventional cylinder head.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Cylinder head 11 Upper stage cooling water path 12 Lower stage cooling water path 13 Partition wall 14 Outlet 14a Outlet 14b Outlet 15a Gasket hole 15b Gasket hole 15c Gasket hole 15d Gasket hole 16 Lower wall 21 Exhaust port 22 Exhaust port 23 Intake port 24 Intake port 25 Mounting portion 31 Port-to-port channel 32 Split channel 320 Split channel 321 Split channel 33 Split channel 330 Split channel 331 Split channel

Claims (8)

A plurality of cooling water passages are formed in the cylinder head, and at least one of the plurality of cooling water passages is connected to at least one cooling water inlet for each cylinder, and from the inlet. Cylinder head provided with an inter-port flow path through which the inflowing cooling water flows, and a cooling water outlet that communicates with another cooling water passage and causes the cooling water that has flowed through the inter-port flow path to flow into the other cooling water passage. In the cooling water passage structure of
The inter-port flow path is divided into two branch flow paths, each of which is configured to flow out to another cooling water passage through different outlets, and the two branch flow paths are divided into downstream flow paths and A cooling water passage structure for a cylinder head, characterized in that the minimum flow passage cross-sectional area of the downstream branch flow passage is smaller than the minimum flow passage cross-sectional area of the upstream branch flow passage. .   In the two branch channels, SL is the minimum channel cross-sectional area of the shunt channel going downstream, and SU is the minimum channel cross-sectional area of the shunt channel going upstream, and SL / 2. The cooling water passage structure for a cylinder head according to claim 1, wherein the SL / SU ratio in the flow path between ports in the downstream cylinder is equal to or smaller than the SU ratio. A plurality of cooling water passages are formed in the cylinder head, and at least one of the plurality of cooling water passages is connected to at least one cooling water inlet for each cylinder, and from the inlet. Cylinder head provided with an inter-port flow path through which the inflowing cooling water flows, and a cooling water outlet that communicates with another cooling water passage and causes the cooling water that has flowed through the inter-port flow path to flow into the other cooling water passage. In the cooling water passage structure of
The inter-port passage is divided into two branch passages, and is configured to flow out to other cooling water passages through different outlets, and the minimum of the branch passages toward the downstream side in the two branch passages. SL is the channel cross-sectional area, and SU is the minimum channel cross-sectional area of the shunting channel toward the upstream side. The SL / SU ratio in the port-to-port channel in the upstream cylinder is the port-to-port channel in the downstream cylinder. A cooling water passage structure for a cylinder head, wherein the SL / SU ratio of the cylinder head is equal to or smaller than at least a part of the upstream and downstream cylinders .   The cylinder head is provided with two intake ports and two exhaust ports for each cylinder, and the inter-port flow path is divided between each exhaust port and the intake air by the cooling water passing between the two exhaust ports. The cooling water passage structure for a cylinder head according to any one of claims 1 to 3, wherein the cooling water passage structure is formed so as to flow between the ports.   5. The cooling water passage structure for a cylinder head according to claim 4, wherein the cooling water inlet is provided in the vicinity between two exhaust ports.   For each cylinder, the outlet of the diversion channel going to the downstream side and the outflow port of the diversion channel going to the upstream side are formed independently, and the opening surface of the outflow port forms a part of the flow path cross section of the diversion channel The cooling water passage structure for a cylinder head according to any one of claims 1 to 5, wherein   The other cooling water passage with which the said outflow port is connected has the flow-path cross-sectional area corresponding to each cylinder, or the downstream is equal or enlarged compared with the upstream. A cooling water passage structure for a cylinder head according to any one of the above.   The cooling water passage for a cylinder head according to any one of claims 1 to 7, wherein the plurality of cooling water passages are formed separately in two upper and lower stages of an upper cooling water passage and a lower cooling water passage. Construction.

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