JP2010265840A - Cylinder head water jacket structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To firmly support a core for forming a water jacket at the time of casting of a cylinder head while securing cooling performances of high temperature sections around a combustion chamber by providing a rib in the water jacket of the cylinder head. <P>SOLUTION: The figure shows the core for forming the water jacket in the cylinder head. A passage expansion part 20 is provided in the water jacket between adjacent combustion chambers, cooling water is divided to a pair of main cooling water passages 20a by a rib 21 erectly provided at a center thereof, and parts near an intake valve hole 14, an exhaust valve hole 15, and a spark plug insertion through-hole 16 where temperature becomes high are cooled. A through channel 20c and a branch channel 20d are formed in a T-shape in the rib 21, and a core pin is made abut on a crossing part thereof (a position where a cap 23 covering the pin hole is installed) from an upper part. Consequently, not only the core is firmly supported in a die at the time of casting of the cylinder head, but also useless material of the rib 21 of quantity of a pin hole is reduced to reduce weight of the cylinder head. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a water jacket structure for a cylinder head in which a water jacket for cooling the periphery of a plurality of combustion chambers is formed inside a cylinder head of a multi-cylinder engine.

  A water jacket that flows cooling water in a direction perpendicular to the cylinder row (intake and exhaust direction) inside the cylinder head of the engine, and is located between two combustion chambers adjacent to each other in the cylinder row direction Patent Document 1 below discloses that a T-shaped rib (reserving column 26) is provided to cool the high-temperature portion near the combustion chamber by branching the flow of cooling water to both sides of the rib. .

Japanese Patent Publication No. 7-015275

  By the way, as described in Patent Document 1, when a rib for restricting the flow of cooling water is provided, the weight of the cylinder head increases by the amount of the rib. desirable.

  In order to form a water jacket on the cylinder head, it is necessary to hold the core inside the mold for casting the cylinder head. In order to firmly support the core inside the mold by the core pin, It is desirable to set the position of the core pin at the center of two adjacent combustion chambers. However, as described in Patent Document 1, if a rib is arranged at the center of two adjacent combustion chambers, the position of the core pin is set to two adjacent positions in order to avoid interference with the rib. It is necessary to shift from the center of the combustion chamber or to reduce the diameter of the core pin, and the support of the core by the core pin may become unstable.

  The present invention has been made in view of the above circumstances, and a core for forming a water jacket at the time of casting of the cylinder head while providing a rib on the water jacket of the cylinder head to ensure the cooling performance of the high temperature portion around the combustion chamber. The purpose is to enable strong support.

  In order to achieve the above object, according to the first aspect of the present invention, a combustion chamber that divides the combustion chamber into a cylinder head of a multi-cylinder engine in which a plurality of combustion chambers are arranged in a cylinder row direction. A water jacket for flowing cooling water in the intake / exhaust direction to cool the vicinity of the upper wall of the combustion chamber, and an upstream valve located on the upstream side in the flow direction of the cooling water. A hole, a downstream valve hole located downstream in the flow direction of the cooling water, and a member insertion hole to be cooled into which at least one of the spark plug and the fuel injection valve is inserted at a position sandwiched between the valve holes. The water jacket has a water jacket structure for a cylinder head having a passage expansion portion in which a passage cross-sectional area expands between adjacent combustion chambers, and an upper wall wall of the water jacket is formed at the center of the passage expansion portion. And a rib that connects the lower wall and biases the flow of the cooling water toward the upstream valve hole, the downstream valve hole, and the member to be cooled insertion hole, and the rib is arranged in a cylinder row direction. A penetrating water passage and a pin hole penetrating from the through water passage to the upper surface of the cylinder head are formed, and the pin hole located at the center of the passage extension portion when viewed in the cylinder axial direction is formed by casting the cylinder head. A water jacket structure for a cylinder head is proposed, characterized in that it is sometimes formed by a core pin that holds a core for forming the water jacket.

  According to the second aspect of the present invention, in addition to the configuration of the first aspect, the rib extends from the connecting portion of the through water channel and the pin hole to the downstream side in the flow direction of the cooling water. A water jacket structure for a cylinder head is proposed, in which a branch water channel communicating with the expansion portion is formed.

  The intake valve hole 14 of the embodiment corresponds to the upstream valve hole of the present invention, the exhaust valve hole 15 of the embodiment corresponds to the downstream valve hole of the present invention, and the spark plug insertion hole of the embodiment. 16 corresponds to the member to be cooled insertion hole of the present invention.

  According to the configuration of the first aspect, the water jacket for flowing cooling water in the intake and exhaust directions, the upstream valve hole, the downstream valve hole, and the member to be cooled are inserted into the combustion chamber upper wall of the cylinder head of the multi-cylinder engine. The water jacket has a passage extension that expands the cross-sectional area of the passage between adjacent combustion chambers, and a rib is formed in the center of the passage extension. By deviating toward the upstream valve hole, the downstream valve hole, and the member insertion hole to be cooled, the cooling effect of the high temperature portion can be enhanced. The rib is formed with a through water passage penetrating in the cylinder row direction and a pin hole penetrating from the through water passage to the upper surface of the cylinder head in the center of the passage expansion portion as seen in the cylinder axial direction. The core for forming the water jacket can be firmly held by the core pin for forming the pin hole at the time of casting the cylinder head, and the ribs of the rib can be reduced by the amount of the pin hole. Weight can be reduced.

  According to the second aspect of the present invention, since the branch water channel extending from the connecting portion of the through water channel and the pin hole to the downstream side in the flow direction of the cooling water and communicating with the passage expansion portion is formed in the rib, the through water channel and the branch water channel Ribs can be reduced to reduce the weight of the cylinder head, and the ribs can be cooled by cooling water flowing through the through water channel and the branch water channel.

Sectional drawing of the direction orthogonal to the cylinder axis line of the cylinder head of an in-line four cylinder engine. FIG. 2 is an enlarged sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 4 is a cross-sectional view taken along line 4-4 of FIG. FIG. The top view of the core which shape | molds the water jacket of a cylinder head. The bottom view of the core which shape | molds the water jacket of a cylinder head. FIG.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a cross-sectional view of a cylinder head 11 of an in-line four-cylinder engine cut along a plane parallel to a coupling surface with a cylinder block, as viewed from above (head cover side). The upper side is the exhaust side. Four combustion chambers 12 are arranged along the cylinder line L1 on the lower surface (the back side of the paper surface) of the cylinder head 11, and two intake valve holes are formed in the combustion chamber upper wall 13 shown in cross section. 14, two exhaust valve holes 15, 15 and a spark plug insertion hole 16 surrounded by them are formed.

  Inside the cylinder head 11, a water jacket J surrounded by an intake side wall 11a, a timing chain chamber side wall 11b, an exhaust side wall 11c and a transmission side wall 11d is shown in white. 6 and 7 show the shape of the core 17 used when casting the cylinder head 11, and the shape of the core 17 is the same as the shape of the water jacket J. FIG. Hereinafter, the structure of the water jacket J will be described with reference to FIGS. 1, 6, and 7.

  The water jacket J connects the intake side gallery 18 along the intake side side wall 11 a of the cylinder head 11, the exhaust side gallery 19 along the exhaust side side wall 11 c of the cylinder head 11, and the intake side gallery 18 and the exhaust side gallery 19. Individual passage expansion portions 20... The three passage expansion portions 20 are arranged on the cylinder row line L1 and at positions sandwiched between the four combustion chambers 12. The intake side gallery 18 and the exhaust side gallery 19 at the lower position of the cylinder head 11 are indicated by solid lines in FIG. 1, but the three passage expansion portions 20 are higher than the intake side gallery 18 and the exhaust side gallery 19. Because of its position, it is shown in phantom in FIG.

  A cooling water inlet 18a to which cooling water is supplied from a cooling water pump provided in the cylinder block is provided on the lower surface of the intake side gallery 18, and the four cylinder axes L2,. Four first cooling water passages 18b extend from the cooling water inlet 18a toward the position a. From the four a positions, each of the two second cooling water passages 18c extends toward the cylinder row line L1, and the three to six second cooling water passages 18c that gather together are The three passage positions 20 between the four combustion chambers 12 communicate with the three passage extensions 20.

  A total of eight second cooling water passages 18c are formed with communication holes 18d communicating with the water jacket on the cylinder block side, and a part of the cooling water flowing through the intake side gallery 18 is formed with the communication holes 18d. Is distributed to the water jacket on the cylinder block side. Further, the exhaust side gallery 19 is formed with four communication holes 19a at positions shifted from the four cylinder axis lines L2 to the exhaust side, and a part of the cooling water flowing through the exhaust side gallery 19 is in communication. It passes through the holes 19a and is distributed to the water jacket on the cylinder block side. Two cooling water outlets 19b and 19b are formed at a position near the transmission side wall 11d of the exhaust side gallery 19, and the cooling water that has flowed through the water jacket J to the end passes through the cooling water outlets 19b and 19b to form a cylinder. Returned to the water jacket on the block side.

  Next, the structure of the channel | path extension part 20 is demonstrated based on FIGS.

  Since the three passage expansion portions 20 at positions sandwiched by the four combustion chambers 12 on the cylinder line L1 have substantially the same structure, the one passage expansion portion 20 will be described below. .

  The passage expanding portion 20 communicates the intake side gallery 18 and the exhaust side gallery 19, and by forming a rib 21 in the vertical direction at the center thereof, the cooling water is moved in the left and right direction (two sandwiching the passage expanding portion 20). Two main cooling water passages 20a, 20a are formed for diversion in the direction of the two combustion chambers 12, 12. Accordingly, the cooling water flowing through the passage expanding portion 20 branches to the two main cooling water passages 20a and 20a that bypass the rib 21 at the b position on the intake side, and then merges again at the c position on the exhaust side to form the exhaust side gallery. 19 flows into.

  That is, as is apparent from FIG. 8, the cooling water flowing into the passage expanding portion 20 at the position b is blocked by the rib 21 and branches into the left and right main cooling water passages 20a and 20a, and the intake valve holes 14 and 14 are formed. After cooling the wall portions 11e and 11e, the wall portion 11f in which the spark plug insertion hole 16 is formed, and the wall portions 11g and 11g in which the exhaust valve holes 15 and 15 are formed, at the position c on the exhaust side. It merges again and flows into the exhaust side gallery 19.

  Two main cooling water passages 20a, 20a opposite to each other of two passage expansion portions 20, 20 adjacent to each other in the direction of the cylinder line L1 are provided with wall portions 11e, 11e in which intake valve holes 14, 14 are formed, and ignition. It is connected by a communication water passage 20b disposed between the wall portion 11f in which the plug insertion hole 11f is formed, and the wall portions 11e and 11e of the intake valve holes 14 and 14 and the ignition by the cooling water flowing through the communication water passage 20b. The wall portion 11f of the plug insertion hole 16 is further cooled.

  In FIG. 8, the flow rate of the cooling water (see arrow A1) flowing through the main cooling water passage 20a of the left passage expansion portion 20 and the cooling water flowing through the main cooling water passage 20a of the right passage expansion portion 20 (see arrow A2). If the flow rate of the refrigerant is antagonized, the cooling water stays in the communication water passage 20b that allows the two main cooling water passages 20a and 20a to communicate with each other, and the wall portions 11e of the intake valve holes 14 and 14 that the communication water passage 20b faces. 11e and the cooling effect of the wall portion 11f of the spark plug insertion hole 16 are reduced.

  In order to solve this problem, in the present embodiment, one of the wall portions 11e and 11e of the left and right intake valve holes 14 and 14 facing the opening portions at both ends of the communication water channel 20b (in the embodiment, on the right side of FIG. 8). A protruding portion 11h that protrudes from the intake side toward the exhaust side is formed in the wall portion 11e) of the intake valve hole 14.

  By forming this protrusion 11h, the cooling water (see arrow A2) flowing through the main cooling water passage 20a on the right side in the figure is directed to the exhaust side and hardly flows into the right end opening of the communication water passage 20b. On the other hand, the cooling water (see arrow A1) flowing through the main cooling water passage 20a on the left side in the figure is likely to flow into the left end opening of the communication water passage 20b because there is no protrusion 11h, and the communication is lost due to the loss of the balance. The flow of the cooling water from the left to the right indicated by the arrow A3 is generated in the water channel 20b, and the cooling effect of the wall portions 11e, 11e of the intake valve holes 14, 14 and the wall portion 11f of the spark plug insertion hole 16 can be enhanced. .

  In addition, it is desirable to provide the side where the protrusion 11h is provided on the side of the left and right main cooling water passages 20a, 20a where the flow rate of the cooling water is low. The reason is that by providing the protrusion 11h, the main cooling water passage 20a is throttled and the flow velocity increases, so the flow velocity of the cooling water flowing in the left and right main cooling water passages 20a, 20a is made uniform, and the cooling effect is made uniform. Because it can be done.

  Next, the structure of the rib 21 provided in the center of the channel | path expansion part 20 is demonstrated based on FIGS. 2-5 and FIG.

  The rib 21 erected at the center of the passage expanding portion 20 is formed in a substantially columnar shape, and both ends of the through water passage 20c formed in the direction of the cylinder row line L1 are left and right main cooling water passages 20a and 20a. Open to. A branch water channel 20 d extends from the central portion of the through water channel 20 c toward the exhaust side, and an outlet end thereof opens at a point c of the exhaust side gallery 19. The through water channel 20c and the branch water channel 20d are formed in a substantially T shape in the horizontal cross section (see FIGS. 4 and 8), and the rib 21 is formed by one semicircular portion and two fan-shaped portions in the horizontal cross section. To separate. Accordingly, a part of the cooling water flowing through the left and right main cooling water passages 20a, 20a flows in from both ends of the through water channel 20c and flows toward the center, then flows into the branch water channel 20d and flows out to the exhaust side gallery 19. To do.

  In the upper half of the rib 21, a pin hole 21 a that extends upward from the intersection of the through water channel 20 c and the branch water channel 20 d and penetrates to the upper surface of the cylinder head 11 is formed. The bottom of the pin hole 21a, that is, the upper side of the intersecting portion of the through water channel 20c and the branch water channel 20d is closed by the press-fitting of the cap 22, thereby preventing the cooling water from leaking from the pin hole 21a.

  When the cylinder head 11 is cast, the core 17 (see FIGS. 6 and 7) for forming the water jacket J is supported in the cavity of the mold via a plurality of core pins. The lower end of the core pin 23 (see FIGS. 2 and 5) of the book corresponds to the center portion of the rib 21, more specifically, the portion where the intersection of the penetrating water channel 20c and the branch water channel 20d of the core 17 is formed. By contact, the core 17 is held in the mold.

  3 and 4, reference numeral 24... Is an intake port connected to the intake valve hole 14..., And 25 is an exhaust port connected to the exhaust valve hole 15.

  As described above, the core pin 23 is inserted into the central portion of the rib 21 to form the pin hole 21a, and therefore the weight of the cylinder head 11 is reduced by reducing the thickness of the rib 21 by the amount of the pin hole 21a. Can do. Further, it is difficult to secure the arrangement space for arranging the core pin 23 while avoiding the position of the rib 21, or it becomes difficult to arrange the core pin 23 at an appropriate position, thereby strengthening the core 17. Although it cannot be supported, according to the present embodiment, the above problem can be solved.

  Further, since the through water channel 20c and the branch water channel 20d are formed inside the rib 21, it is possible to further reduce the weight of the cylinder head 11 by reducing the thickness of the rib 21, and to effectively cool the rib 21. be able to.

  The embodiments of the present invention have been described above, but various design changes can be made without departing from the scope of the present invention.

  For example, in the water jacket J of the embodiment, the cooling water flows from the intake side to the exhaust side of the cylinder head 11, but the cooling water may flow from the exhaust side to the intake side.

  The member to be cooled inserted into the member to be cooled insertion hole of the present invention is a spark plug, but the member to be cooled may be a fuel injection valve.

  In the embodiment, the rib 21 is provided with the through water channel 20c and the branched water channel 20d, but the branched water channel 20d can be omitted.

11 Cylinder head 12 Combustion chamber 13 Combustion chamber upper wall 14 Intake valve hole (upstream valve hole)
15 Exhaust valve hole (downstream valve hole)
16 Spark plug insertion hole (cooled member insertion hole)
17 Core 20 Passage expansion part 20c Through water channel 20d Branch water channel 21 Rib 21a Pin hole 23 Core pin L1 Cylinder row line L2 Cylinder axis J Water jacket

Claims (2)

A combustion chamber upper wall (13) that partitions the combustion chamber (12) into a cylinder head (11) of a multi-cylinder engine in which a plurality of combustion chambers (12) are arranged in a cylinder row line (L1) direction, and the combustion A water jacket (J) for flowing cooling water in the intake and exhaust directions to cool the vicinity of the upper wall (13);
In the combustion chamber upper wall (12), an upstream valve hole (14) located on the upstream side in the flow direction of the cooling water, a downstream valve hole (15) located on the downstream side in the flow direction of the cooling water, A cooled member insertion hole (16) into which at least one of the spark plug and the fuel injection valve is inserted is formed at a position sandwiched between both valve holes (14, 15),
The water jacket (J) has a water jacket structure of a cylinder head including a passage expansion portion (20) in which a passage cross-sectional area expands between adjacent combustion chambers (12),
An upper wall and a lower wall of the water jacket (J) are connected to the center of the passage extension (20) so that the flow of cooling water flows to the upstream valve hole (14), the downstream valve hole (15), and Ribs (21) that are biased toward the cooled member insertion holes (16) are formed,
The rib (21) has a through water passage (20c) penetrating in the direction of the cylinder row (L1) and a pin hole (21a) penetrating from the through water passage (20c) to the upper surface of the cylinder head (11). The pin hole (21a) formed and positioned in the center of the passage extension (20) when viewed in the direction of the cylinder axis (L2) forms the water jacket (J) when the cylinder head (11) is cast. A water jacket structure for a cylinder head, wherein the water jacket structure is formed by a core pin (23) for holding a core (17).   The rib (21) has a branch water channel (20d) extending from the connecting portion of the through water channel (20c) and the pin hole (21a) to the downstream side in the flow direction of the cooling water and communicating with the passage expansion portion (20). The water jacket structure for a cylinder head according to claim 1, wherein:

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