JP6728952B2 - Cylinder head of internal combustion engine - Google Patents

Description

The present invention relates to a cylinder head of an internal combustion engine.

A cylinder head of an internal combustion engine is provided with a water jacket for cooling a combustion chamber with cooling water, a plug mounting portion for mounting a spark plug, and the like.
In such a cylinder head, in order to suppress a difference in the cooling effect of the combustion chamber between the cylinders, for example, in the cylinder head described in Patent Document 1, an inter-cylinder flow path for flowing cooling water between the combustion chambers of adjacent cylinders Is attached to the water jacket. Further, in order to enhance the cooling effect of the plug mounting portion having a high heat load, such inter-cylinder flow passage is provided with a projection for guiding the cooling water flowing through the inter-cylinder flow passage to the plug mounting portion.

JP-A-5-86969

By the way, when the protrusion is provided in the inter-cylinder flow passage, the pressure loss in the portion where the protrusion is provided in the inter-cylinder flow passage increases, so that the flow rate of the cooling water in the downstream of the protrusion decreases and, for example, the cooling effect by the cooling water May decrease.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a cylinder of an internal combustion engine capable of suppressing a decrease in the cooling water flow rate downstream of a projection provided in an inter-cylinder flow path of a water jacket. To provide a head.

A cylinder head of an internal combustion engine that solves the above-mentioned problems is a cylinder head that includes a water jacket that cools a combustion chamber of the internal combustion engine with cooling water and a plug mounting portion that mounts an ignition plug, and the water jackets are adjacent cylinders. An inter-cylinder flow path for flowing cooling water between the combustion chambers is provided, and the inter-cylinder flow path is provided with a projection that guides the cooling water flowing through the inter-cylinder flow path to the plug mounting portion, In the flow passage on the downstream side of the protrusion in the inter-cylinder flow passage, a flow passage enlarged portion is formed so that the vertical width of the flow passage becomes wider toward the downstream side.

The "vertical width" of the same configuration means that the direction in which the cylinder head cover mounting surface is provided in the cylinder head is the upward direction, and the direction in which the cylinder block mounting surface is provided in the cylinder head is the downward direction. It means the width of the flow path in the up-and-down direction.

According to this configuration, in the flow path on the downstream side of the protrusion in the inter-cylinder flow path, the flow path enlarged portion is formed so that the vertical width of the flow path becomes wider toward the downstream side. Therefore, the flow passage cross-sectional area in the flow passage on the downstream side of the protrusion becomes wider toward the downstream side, which reduces the pressure loss on the downstream side of the protrusion. Therefore, it becomes possible to suppress a decrease in the cooling water flow rate downstream of the protrusion.

FIG. 3 is a longitudinal sectional view of a cylinder head of an internal combustion engine in one embodiment. Sectional drawing of the cylinder head along the AA line shown in FIG. FIG. 3 is a partially enlarged view in the vicinity of a flow path between cylinders of a cylinder head. Sectional drawing of the longitudinal direction of the cylinder head in the modification of the embodiment.

An embodiment in which a cylinder head of an internal combustion engine is embodied will be described below with reference to FIGS. 1 to 3.
As shown in FIG. 1, in this cylinder head 100, a plurality of combustion chambers 10 (shown by broken lines in FIG. 1) are provided on the lower surface to which the cylinder block is attached. Further, in the cylinder head 100, an intake port 20 for introducing intake air into the combustion chamber 10 and an exhaust port 30 for exhausting exhaust gas from the combustion chamber 10 are formed for each combustion chamber 10. Further, a plug mounting portion 6 for mounting a spark plug is provided between the pair of intake ports 20 and exhaust port 30.

The cylinder head 100 is integrally formed with an exhaust manifold (not shown) in which the exhaust ports 30 are assembled.
A combustion chamber water jacket 110 that extends in the longitudinal direction of the cylinder head 100 (direction of arrow L shown in FIG. 1) and cools each combustion chamber 10 with cooling water of the internal combustion engine is integrated with the cylinder head 100. Has been formed. The cylinder head 100 is provided with a flow path (not shown) for introducing the cooling water, which has passed through the water jacket provided in the cylinder block of the internal combustion engine, into the combustion chamber water jacket 110.

Further, the cylinder head 100 is integrally formed with an exhaust manifold water jacket 120 that allows cooling water of the internal combustion engine to flow around the exhaust manifold. The exhaust manifold water jacket 120 cools the exhaust manifold with cooling water. The cylinder head 100 introduces the cooling water after passing through the water jacket provided in the cylinder block of the internal combustion engine and the cooling water after passing through the combustion chamber water jacket 110 into the exhaust manifold water jacket 120. Is provided (not shown). The exhaust manifold integrally formed with the cylinder head and the exhaust manifold water jacket for cooling the exhaust manifold have well-known configurations, and a detailed description thereof will be omitted.

The combustion chamber water jacket 110 is provided with an inter-cylinder flow channel 115 (a flow channel in a region surrounded by a two-dot chain line in FIG. 1) that flows between the combustion chambers 10 of adjacent cylinders. Cooling water that has passed through the water jacket provided in the cylinder block of the internal combustion engine flows into the intake port 20 side of the inter-cylinder flow path 115 through a flow path (not shown). The cooling water flowing into the intake port 20 side of the inter-cylinder flow path 115 flows through the inter-cylinder flow path 115 toward the exhaust port 30 side. The cooling water that has passed through the inter-cylinder flow path 115 from the intake port 20 side toward the exhaust port 30 side in this way flows into the exhaust manifold water jacket 120 via a flow path (not shown), and then the cylinder head 100. It is discharged to the outside of the cylinder head 100 by flowing into the cooling water pipe connected to.

Further, each inter-cylinder flow path 115 is provided with a first projection 51 that functions as a projection that guides the cooling water flowing through the inter-cylinder flow path 115 to the plug mounting portion 6. The first protrusion 51 extends in the longitudinal direction of the cylinder head 100 and extends in a direction substantially orthogonal to the flow direction of the cooling water flowing through the inter-cylinder flow passage 115. Further, a second protrusion 52 extending in the cooling water flow direction is provided from a central portion of the first protrusion 51 in the longitudinal direction of the cylinder head 100. As shown in FIG. 1, the width W2 of the second protrusion 52 in the longitudinal direction of the cylinder head 100 is shorter than the width W1 of the first protrusion 51 in the longitudinal direction of the cylinder head 100, and the width of the inter-cylinder flow path 115 increases. Is provided with a substantially T-shaped protrusion 50 composed of a first protrusion 51 and a second protrusion 52.

FIG. 2 shows a cross section of the inter-cylinder flow path 115 along the flow direction of the cooling water. In FIG. 2, the direction in which the head cover mounting surface 140 for mounting the cylinder head cover in the cylinder head 100 is provided is the upward direction, and this is indicated by an arrow Y1. Further, the direction in which the block mounting surface 150 for mounting the cylinder block in the cylinder head 100 is provided is the downward direction, and this is indicated by arrow Y2.

As shown in FIG. 2, the first projections 51 and the second projections 52 project in a state of extending from the upper wall surface 115U of the inter-cylinder flow path 115 toward the lower wall surface 115D halfway, and these first projections The protrusion amounts of 51 and the second protrusion 52 are substantially the same.

Further, in the inter-cylinder flow passage 115, a flow passage enlarged portion 116 formed such that the vertical width H of the flow passage becomes wider toward the downstream side is provided in the flow passage on the downstream side of the first protrusion 51. .. In the cross-sectional view shown in FIG. 2, the vertical width HL of the flow passage 117 of the inter-cylinder flow passage 115 on the downstream side of the flow passage enlarged portion 116 is smaller than the vertical width H of the flow passage enlarged portion 116. There is. However, since the flow passage 117 is widened in the longitudinal direction of the cylinder head 100 (the direction from the front to the back on the paper surface of FIG. 2), the pressure loss in the flow passage 117 is equal to the pressure loss in the flow passage expanding portion 116. Alternatively, the pressure loss is lower than the pressure loss in the enlarged flow passage portion 116.

With the cylinder head 100 configured as described above, the following operational effects can be obtained.
(1) As shown in FIG. 3, the flow direction of the cooling water that has flowed into the inter-cylinder flow path 115 is changed by the first protrusions 51 and flows toward the plug mounting portion 6. Therefore, it is possible to enhance the cooling effect of the cooling water with respect to the plug mounting portion 6 having a high heat load.

(2) As shown in FIG. 3, the cooling water flowing toward the plug mounting portion 6 returns to the inter-cylinder flow path 115 again while flowing toward the exhaust port 30 side. Here, the cooling water returns to the inter-cylinder flow path 115 from the plug mounting portions 6 of the adjacent combustion chambers 10. However, the respective returning cooling water is suppressed from being mixed by the second projections 52. .. Therefore, it is possible to prevent the cooling water from flowing from one side of the adjacent combustion chambers 10 toward the other side, which can promote the uniformization of the cooling water flow rate between the combustion chambers 10.

(3) The first protrusions 51 and the second protrusions 52 provided in the inter-cylinder flow passage 115 also function as ribs for increasing the rigidity in the formation portion of the inter-cylinder flow passage 115. Therefore, as compared with the case where the first protrusion 51 and the second protrusion 52 are not provided, the rigidity at the portion where the inter-cylinder flow path 115 is formed is improved. Therefore, for example, the deformation of the cylinder head 100 at the time of fastening the cylinder head 100 and the cylinder block with a bolt can be suppressed, whereby the sealing property of the head gasket sandwiched between the cylinder head 100 and the cylinder block is improved. Will improve.

(4) As shown in FIG. 1 above, the width W2 of the second protrusion 52 is made smaller than the width W1 of the first protrusion 51. Therefore, as compared with the case where the width W2 of the second protrusion 52 is the same as the width W1 of the first protrusion 51 or the width W2 of the second protrusion 52 is longer than the width W1 of the first protrusion 51, It is possible to suppress an increase in pressure loss in the inter-cylinder flow path 115 due to the provision of the two protrusions 52.

(5) The first protrusion 51 extends in the inter-cylinder flow path 115 in a direction substantially orthogonal to the flow direction of the cooling water. Therefore, if the first protrusion 51 is simply provided in the inter-cylinder flow passage 115, the pressure loss at the portion where the first protrusion 51 is provided in the inter-cylinder flow passage 115 increases, and the downstream side of the first protrusion 51. The flow rate of the cooling water in is reduced. Therefore, for example, the cooling effect of the cooling water may decrease.

In this respect, in the cylinder head 100 of the present embodiment, as shown in FIG. 2 above, in the inter-cylinder flow passage 115, in the flow passage on the downstream side of the first protrusion 51, the vertical width H of the flow passage is downstream. The flow channel expanding portion 116 is formed so as to become wider toward the. Therefore, the flow passage cross-sectional area in the flow passage on the downstream side of the first protrusion 51 becomes wider toward the downstream side, and thus the pressure loss downstream of the first protrusion 51 becomes smaller. Therefore, it is possible to suppress a decrease in the flow rate of the cooling water downstream of the first protrusion 51.

The above-described embodiment can also be implemented in the following modes, which are appropriately modified.
Although the protrusion 50 has a substantially T shape, other shapes may be used as long as the cooling water can be guided to the plug mounting portion 6. For example, it may have an arrow shape pointing to the upstream direction in the flow direction of the cooling water.

In the cylinder head 100 of the above embodiment, the first protrusion 51 and the second protrusion 52 are provided in the inter-cylinder flow path 115. In addition, as shown in FIG. 4, even if the cylinder head 200 is provided with the first projection 51 in the inter-cylinder flow path 115 but not with the second projection 52, the inter-cylinder flow path is provided. By providing the flow path expanding portion 116 in the 115, it is possible to obtain operational effects other than the above (2) and (4).

6... Plug attachment part, 10... Combustion chamber, 20... Intake port, 30... Exhaust port, 50... Projection part, 51... First projection, 52... Second projection, 100... Cylinder head, 110... Combustion chamber water jacket , 115... Inter-cylinder flow path, 115D... Lower wall surface, 115U... Upper wall surface, 116... Flow path enlarged portion, 117... Flow path, 120... Exhaust manifold water jacket, 140... Head cover mounting surface, 150... Block mounting surface, 200... Cylinder head.

Claims (1)

A water jacket for cooling the combustion chamber of the internal combustion engine with cooling water, a plug mounting portion for mounting a spark plug, and a port provided on one side and the other side across the plug mounting portion in a direction orthogonal to the cylinder alignment direction, A cylinder head provided with,
The water jacket comprises a cylinder-by-cylinder passage for flowing the cooling water between the combustion chamber of the cylinder adjacent with provided between said one port and the other port,
On the one port side of the inter-cylinder flow path, a flow path for inflowing cooling water into the inter-cylinder flow path is connected,
The inter-cylinder flow path is provided with a projection that guides cooling water flowing from the one port side of the inter-cylinder flow path to the other port side to the plug mounting portion,
The protrusion has a first protrusion and a second protrusion that protrude from the upper wall surface of the inter-cylinder flow passage toward the lower wall surface in the middle,
The first protrusion extends in the direction in which the adjacent cylinders are arranged,
The second protrusion extends from the middle of the first protrusion in the direction in which the adjacent cylinders are arranged to the downstream side in the cooling water flow direction,
The width of the second protrusion in the arrangement direction of the adjacent cylinders is shorter than the width of the first protrusion in the arrangement direction of the adjacent cylinders,
In the inter-cylinder flow passage, a flow passage enlarged portion is formed in the flow passage on the downstream side of the first protrusion so that the vertical width of the flow passage becomes wider toward the downstream side. head.

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