cylinder head

Abstract

Provided is a cylinder head capable of suppressing an increase in pressure loss in a water jacket and improving cooling performance. The cylinder head has a mounting hole that is opened in a wall surface that demarcates a combustion chamber of an internal combustion engine and that mounts a spark plug, an intake port and an exhaust port that are disposed on opposite sides of the mounting hole, a first flow path of cooling water that is connected to a water jacket in a cylinder block from the combustion chamber side, that is adjacent to the intake port, and that extends along the wall surface toward the mounting hole, and a second flow path of cooling water that is connected to the water jacket from the combustion chamber side, that is adjacent to the exhaust port, and that extends along the wall surface toward the mounting hole, at least one of the first flow path and the second flow path having a protrusion that protrudes in a direction inclined toward the combustion chamber side with respect to a direction in which the at least one flow path is adjacent to the intake port and the exhaust port.

Description

Technical Field

[0001] This invention relates to a cylinder head. Background Technology

[0002] Regarding the cylinder head of an internal combustion engine, for example, Patent Document 1 describes the following: In order to improve the flow rate distribution of cooling water near the combustion chamber, an embossed portion protruding from the upper part of the inner wall of the flow path downwards to the combustion chamber side is provided in the water jacket connected to the cooling water passage on the cylinder block side. Existing technical documents

[0003] Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 7-42612

[0005] The problem that the invention aims to solve

[0006] However, according to the above technology, the embossed part hinders the flow of cooling water, which may increase the pressure loss inside the water jacket. Summary of the Invention

[0007] Therefore, the present invention was made in view of the above-mentioned problems, and its object is to provide a cylinder head that can suppress the increase of pressure loss in the water jacket and improve cooling performance.

[0008] The cylinder head of the present invention is a cylinder head for an internal combustion engine, wherein the cylinder head has: a mounting hole that opens on a wall defining a combustion chamber of the internal combustion engine for mounting a spark plug of the internal combustion engine; an intake port and an exhaust port that are disposed on opposite sides of each other relative to the mounting hole; a first flow path for cooling water that connects to a water jacket inside the cylinder body of the internal combustion engine from the combustion chamber side, is adjacent to the intake port, and extends along the wall towards the mounting hole; and a second flow path for cooling water that connects to a water jacket inside the cylinder body from the combustion chamber side, is adjacent to the exhaust port, and extends along the wall towards the mounting hole.

[0009] At least one of the first flow path and the second flow path has a protrusion that protrudes in a direction inclined toward the combustion chamber side relative to the air inlet and the air outlet adjacent to the at least one flow path and the adjacency direction of the at least one flow path.

[0010] In the cylinder head described above, the flow path of at least one of the components may have a straight section on the upstream side of the protrusion.

[0011] In the cylinder head described above, the air port adjacent to the flow path of at least one of the protrusions may be located on the opposite side of the direction in which the protrusion protrudes.

[0012] In the cylinder head described above, the surface of the protrusion may also have a curved shape.

[0013] According to the present invention, the increase in pressure loss within the water jacket can be suppressed, and the cooling performance of the cylinder head can be improved. Attached Figure Description

[0014] Figure 1 This is a partial sectional view that roughly represents an example of the structure of an engine.

[0015] Figure 2 It is along Figure 1 A cross-sectional view along line AA.

[0016] Figure 3 Viewed from the oblique angle Figure 1 The cross-sectional view of the flow path shown.

[0017] Figure 4 It is along Figure 1 A cross-sectional view of the BB line.

[0018] Figure 5 This is a diagram illustrating the flow of cooling water within a flow path.

[0019] Explanation of reference numerals in the attached figures

[0020] 1 Cylinder head, 2 Cylinder block, 9 Engine (internal combustion engine), 10 Mounting hole, 11, 12 Flow path, 13, 14 Protrusion, 18 Intake port, 17 Exhaust port, 19 Wall, 21, 22 Water jacket, 90 Combustion chamber, 91 Piston, 92 Spark plug, 111, 121 Straight section Detailed Implementation

[0021] (Engine structure)

[0022] Figure 1 This is a partial cross-sectional view that roughly represents an example of the structure of engine 9. Figure 2 It is along Figure 1 A cross-sectional view along line AA. Additionally, in Figures 1 to 5 The diagram shows the mutually orthogonal X, Y, and Z directions.

[0023] Engine 9 is an example of an internal combustion engine mounted in a vehicle, such as a gasoline engine or a diesel engine. Engine 9 has a cylinder head 1 and a cylinder block 2 that are interconnected via a gasket 3. Figure 1 A partial cross-section of engine 9 is shown along the connection direction (Z direction) between cylinder head 1 and cylinder block 2.

[0024] The cylinder head 1 has a spark plug 92 mounting hole 10, coolant flow paths 11 and 12 as part of a water jacket, an exhaust port 17 for exhaust, and an intake port 18 for intake. The mounting hole 10 extends toward the cylinder block 2 in the Z direction and opens on the wall 19 defining the combustion chamber 90 of the engine 9. The spark plug 92 is installed by inserting it into the mounting hole 10. The spark plug 92 ignites the air-fuel mixture in the combustion chamber 90 according to external control.

[0025] The combustion chamber 90 is defined by the lower wall 19 of the cylinder block 2, the cylinder 20 inside the cylinder block 2, and the upper surface of the piston that reciprocates in the Z direction within the cylinder 20 during combustion of the air-fuel mixture. The upper wall 19 of the combustion chamber 90 in the Z direction has an opening for a mounting hole 10, an exhaust port 17, and an intake port 18. The intake port 18 introduces intake air from the outside into the combustion chamber 90, and the exhaust port 17 discharges exhaust gas from the combustion chamber 90 to the outside after combustion.

[0026] Two exhaust ports 17 and two intake ports 18 are provided on opposite sides of the mounting hole 10. In a top view of the engine 9, the two exhaust ports 17 and the intake ports 18 are arranged symmetrically about the mounting hole 10. The exhaust ports 17 and the intake ports 18 extend in a generally straight line from the X-direction end of the cylinder head 1 toward the center, and curve toward the negative Z-direction of the combustion chamber 90 near the mounting hole 10.

[0027] The coolant flow paths 11 and 12 are examples of the first and second flow paths. Flow paths 11 and 12 are located on opposite sides of each other across the mounting hole 10, and are substantially arranged on the same straight line. Flow paths 11 and 12 are adjacent to the exhaust port 17 and the intake port 18 respectively in the Y direction, and extend along the wall 19 of the combustion chamber 90 towards the mounting hole 10. Coolant is introduced into flow paths 11 and 12 from inlets 15 and 16, which open on the cylinder block 2 side, respectively. The combustion chamber 90 is cooled by the flow of coolant in flow paths 11 and 12.

[0028] A flow path 11 extends in the X direction between two exhaust ports 17. The flow path 11 has an inlet 110, a straight section 111, and an outlet 112. The inlet 110 extends in the Z direction and connects to the water jacket 21 inside the cylinder block 2 from the combustion chamber 90 side via an opening 31 in the gasket 3. The water jacket 21 is adjacent to the cylinder 20 in the X direction and extends in the Z direction. At one end of the inlet 110, an inlet 15 is provided at a position corresponding to the opening 31.

[0029] The straight section 111 extends approximately orthogonally to the Z-direction relative to the water jacket 21, communicates with the inlet section 110, and extends linearly in the X-direction. The outlet section 112 communicates with the straight section 111 and extends obliquely relative to the straight section 111 (on the positive side in both the Z and X directions) near the mounting hole 10. As indicated by arrow D1, cooling water is introduced from the water jacket 21 into the inlet section 110 and flows from the straight section 111 through the outlet section 112 to other cylinders.

[0030] Another flow path 12 extends in the X direction between the two air intakes 18. Flow path 12 has an inlet 120, a straight section 121, and an outlet 122. The inlet 120 extends in the Z direction and connects to the water jacket 22 inside the cylinder block 2 from the combustion chamber 90 side via the opening 32 of the gasket 3. The water jacket 22 is provided on the side of the cylinder 20 opposite to the other water jacket 21, adjacent to the cylinder 20 in the X direction and extending in the Z direction. At one end of the inlet 120, an inlet 16 is provided at a position corresponding to the opening 32.

[0031] The straight section 121 extends approximately orthogonally to the Z-direction relative to the water jacket 22, communicates with the inlet section 120, and extends linearly along the X-direction. The outlet section 122 communicates with the straight section 121 and extends obliquely relative to the straight section 121 (positive side in the Z-direction and negative side in the X-direction) near the mounting hole 10. As shown by arrow D2, cooling water is introduced from the water jacket 22 into the inlet section 120 and flows from the straight section 121 through the outlet section 122 to other cylinders.

[0032] Flow paths 11 and 12 have protrusions 13 and 14 at the boundaries of their straight sections 111 and 121 and their outlet sections 112 and 122, respectively. Protrusion 13 protrudes in a direction inclined towards the combustion chamber 90 relative to the adjacent direction of the exhaust port 17 and flow path 11. Protrusion 14 protrudes in a direction inclined towards the combustion chamber 90 relative to the adjacent direction of the intake port 18 and flow path 11. Specifically, protrusions 13 and 14 protrude in a direction inclined towards the negative side of the Z direction relative to the Y direction. Furthermore, in the Y direction, the exhaust port 17 and intake port 18 are provided on the back side of protrusions 13 and 14. The shapes of protrusions 13 and 14 will be described below.

[0033] (shape of convex part)

[0034] Figure 3 Viewed from the oblique angle Figure 1 The cross-sectional view of the flow path 11 shown is shown. Additionally, Figure 4 It is along Figure 1 A cross-sectional view of the BB line. Figure 3 This shows the view as observed from a viewpoint tilted slightly to the X direction relative to the Y direction. Figure 1 The cross section. Figure 4A cross-section of the flow path 11 near the protrusion 13 is shown. In addition, in this example, one flow path 11 and protrusion 13 are illustrated, while the other flow path 12 and protrusion 14 have the same shape as the protrusion 13.

[0035] The cross-section of the flow path 11 is, for example, approximately rectangular. Of the two opposing surfaces in the Z direction, the surface on the positive side in the Z direction is designated as the upper surface 11a, and the surface on the negative side in the Z direction is designated as the lower surface 11b. Similarly, of the two opposing surfaces in the Y direction, the surface on the positive side in the Y direction is designated as the side surface 11d, and the surface on the negative side in the Y direction is designated as the side surface 11c.

[0036] A pair of protrusions 13 facing each other in the Y direction are provided in the flow path 11. One protrusion 13 protrudes from the upper surface 11a and the side surface 11c in the protrusion direction La. The other protrusion 13 protrudes from the upper surface 11a and the side surface 11d in the protrusion direction Lb. The protrusion directions La and Lb are directions inclined towards the combustion chamber 90 side (the negative side of the Z direction) relative to the Y direction adjacent to the exhaust port 17 and the flow path 11.

[0037] Thus, the protrusions 13 protrude from the two corners on the positive side of the Z direction toward the combustion chamber 90 in the cross-section of the flow path 11. Therefore, the main flow of cooling water is guided to the area close to the combustion chamber 90, allowing for more effective cooling of the combustion chamber 90 compared to the case where the protrusions 13 are not provided. Furthermore, in the cross-section of the flow path 11, compared to the case where the protrusions 13 protrude from the upper surface 11a toward the combustion chamber 90 (the negative side of the Z direction), the protrusions 13 protrude obliquely relative to the combustion chamber 90, making it easier for cooling water flowing in from the cylinder block 2 side to flow toward the upper surface 11a, thus reducing resistance to the cooling water. Additionally, a space d is ensured between the pair of protrusions 13 on the upper surface 11a to further reduce resistance to the cooling water, but space d is not necessary.

[0038] Furthermore, the surface of the protrusion 13 has a curved shape. For example, the protrusion 13 bulges out toward the combustion chamber 90 from the corner between the upper surface 11a and the side surfaces 11c and 11d. Therefore, compared to the case where the surface of the protrusion 13 is assumed to be planar, the resistance to cooling water is further reduced. However, the surface of the protrusion 13 is not limited to this and may also be planar.

[0039] Furthermore, the air inlet 18 is located on the opposite side of the protrusion direction La, Lb of the protrusion 13. Therefore, the larger the volume of the protrusion 13, the larger the size of the exhaust port 17 can be. As a result, the exhaust volume of the exhaust port 17 increases. Alternatively, the air inlet 18 can be located on the opposite side of the protrusion 14 of the flow path 12, in which case the intake volume of the air inlet 18 increases. However, the exhaust port 17 and the air inlet 18 are not limited to this, and they may not be located on the opposite side of the protrusions 13 and 14.

[0040] (Effects)

[0041] Figure 5 This is a diagram illustrating the flow of cooling water within flow path 11. Figure 5 express Figure 1 The shape of the flow path 11 is shown, and the direction and thickness of the arrows within the flow path 11 roughly indicate the flow direction and speed of the cooling water. Furthermore, the flow of the cooling water is the result of simulations conducted by the inventors.

[0042] Near the inlet 15 of the inlet section 110, as shown by reference numeral P1, cooling water introduced from the water jacket 21 on the cylinder block 2 side flows in the positive direction of Z. Near the boundary between the inlet section 110 and the straight section 111, as shown by reference numeral P2, the cooling water collides with the upper surface of the flow path 11, thereby dispersing the flow direction.

[0043] However, since the straight section 111 is formed in a straight line, as shown by reference numeral P3, the flow direction of the cooling water can be made consistent in the region downstream of the straight section 111. Downstream of the protrusion 13, as shown by reference numeral P4, the fast-flowing main stream (refer to the thick arrow) does not flow along the upper surface, but rather in a region closer to the combustion chamber 90 than the upper surface. Therefore, the combustion chamber 90 is effectively cooled.

[0044] In this example, because a straight section 111 is provided on the upstream side of the protrusion 13, the flow direction of the temporarily dispersed cooling water can be aligned. Therefore, compared to the case where the straight section 111 is not provided, the flow of cooling water brought by the protrusion 13 can be effectively controlled. Furthermore, it is not necessary to provide the straight section 111. Also, while this example describes one flow path 11, the same effect can be achieved for the other flow path 12.

[0045] In the above embodiments, protrusions 13 and 14 are provided on both sides of the two flow paths 11 and 12, but it is sufficient to provide protrusions 13 and 14 on at least one of the flow paths 11 and 12.

[0046] The above-described embodiments are preferred embodiments of the present invention. However, they are not limited thereto, and various modifications can be made without departing from the spirit of the present invention.

Claims

1. A cylinder head for an internal combustion engine, wherein, The cylinder head has: Mounting holes are openings in the wall of the combustion chamber of the internal combustion engine for mounting the spark plugs of the internal combustion engine; An air inlet and an exhaust outlet are disposed on opposite sides of each other relative to the mounting hole; A first flow path for cooling water, the first flow path being connected from the combustion chamber side to the water jacket inside the cylinder of the internal combustion engine, adjacent to the air intake, and extending along the wall towards the mounting hole; as well as A second flow path for cooling water connects to the water jacket inside the cylinder block from the combustion chamber side, is adjacent to the exhaust port, and extends along the wall towards the mounting hole. At least one of the first flow path and the second flow path has a protrusion. The protrusion protrudes in a direction inclined toward the combustion chamber side relative to the air inlet and the air outlet adjacent to the flow path of at least one of the air inlets and the air outlets.

2. The cylinder head according to claim 1, wherein, The flow path of at least one of them has a straight section on the upstream side of the protrusion.

3. The cylinder head according to claim 1 or 2, wherein, An air port adjacent to the flow path of at least one of the protrusions is disposed on the opposite side of the direction in which the protrusion protrudes.

4. The cylinder head according to claim 1 or 2, wherein, The surface of the protrusion has a curved shape.

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