JP2013072364A - Cylinder head cooling structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow the shape of an intake port to be optimized and the strength thereof to be maintained.SOLUTION: In a cylinder head cooling structure with a water jacket 4 formed between intake passage walls 6a, 6b surrounding a plurality of intake ports 2a, 2b and exhaust passage walls 7a, 7b surrounding a plurality of exhaust ports 3a, 3b, an intake port surrounding wall 12 having a solid portion 11 mutually between the plurality of intake ports 2a, 2b and integrally surrounding the plurality of intake ports 2a, 2b is formed.

Description

  The present invention relates to a cylinder head cooling structure.

A cylinder head that is fastened to a cylinder block of a diesel engine and constitutes a part of a combustion chamber is a complicatedly shaped component that is accompanied by an air supply / exhaust system, a valve operating system, a fuel injection system, and the like.
A water jacket composed of a gap through which cooling water flows is formed inside the cylinder head so as to cool a high-temperature portion heated by heat from the cylinder (for example, Patent Documents 1 and 2). reference).

  2 is a cut-away side view showing an example of a conventional cylinder head, FIG. 3 is a plan view of a water jacket as seen from the III-III direction in FIG. 2, wherein 1 is a cylinder head, 2 (2a, 2b) Is an intake port, 3 (3a, 3b) is an exhaust port, 4 is a water jacket constituting a cooling structure, 5 is a combustion chamber, 6a and 6b are intake passage walls, 7a and 7b are exhaust passage walls, and 8a is an intake port 2a. , 2b and the injector peripheral wall surrounding the injector opening 8 provided at the center of the exhaust ports 3a, 3b.

  In the diesel engine to which the cylinder head cooling structure of FIG. 3 is applied, the valve arrangement per cylinder is a four-valve type with two intake valves and two exhaust valves. The intake passage walls 6a and 6b surround the intake port 2a and 2b and a valve body portion of an intake valve (not shown) in the circumferential direction, and the exhaust passage walls 7a and 7b are connected to the exhaust port 3a. , 3b and a valve body portion of an exhaust valve (not shown) are circumferentially surrounded.

  Cooling water inlets 9 and 10 for feeding the cooling water W from the cylinder block to the water jacket 4 are drilled at one predetermined position of the cylinder head 1, from the cooling water inlets 9 and 10. The cooling water W flows between the passage walls 6a, 6b, 7a, 7b and toward the gap around the injector peripheral wall 8a. The water jacket 4 is formed corresponding to each of a plurality of combustion chambers 5 (multiple cylinders).

  In the cylinder head cooling structure shown in FIG. 3, the cooling water W from the cooling water inlets 9 and 10 flows into the gap of the water jacket 4 and generally moves the cylinder head 1 while flowing through the gap as shown by arrows. In addition to cooling, high-temperature parts such as the combustion surface and the exhaust passage are intensively cooled.

Japanese Patent Laying-Open No. 2005-069095 JP 2009-115031 A

  In the conventional cylinder head cooling structure, as shown in FIG. 3, since the intake passage walls 6a and 6b and the exhaust passage walls 7a and 7b surrounding the intake ports 2a and 2b and the exhaust ports 3a and 3b independently are provided, The gap between the intake passage walls 6a and 6b, the exhaust passage walls 7a and 7b, and the injector peripheral wall 8a is narrow, and in particular, the gap X is narrow between the intake passage wall 6a and the injector peripheral wall 8a. FIG. 3 shows a case where the intake passage wall 6b and the injector peripheral wall 8a are integrally formed.

  Further, in order to provide the narrow gap X as described above between the intake passage wall 6a and the injector peripheral wall 8a, the intake port 2a has a distorted shape in which a part is recessed.

  However, as described above, in order to provide the narrow gap X between the intake passage wall 6a and the injector peripheral wall 8a, the intake port 2a has a distorted shape in which a part of the intake port 2a is recessed. Therefore, there is a problem that the intake efficiency is lowered. In order to achieve a compact engine corresponding to the recent high Pmax (maximum in-cylinder pressure), it is required to increase the intake pressure, but the shape of the intake port 2a increases the intake efficiency when the intake pressure is increased. The decline can be significant.

  Further, as the intake pressure is increased, it is necessary to increase the strength around the intake port 2a in the cylinder head 1, but as described above, the intake passage wall 6a surrounding the intake port 2a in order to secure a narrow gap X. Therefore, there is a problem that sufficient strength around the intake port 2a cannot be maintained.

  Further, as described above, since the intake passage walls 6a and 6b and the exhaust passage walls 7a and 7b are provided independently, a gap formed between the intake passage walls 6a and 6b and the exhaust passage walls 7a and 7b. Therefore, there is a problem in that the amount of sand that remains inside the cylinder head 1 after casting increases, which makes it difficult to remove the sand.

  Furthermore, there is a problem that it is very difficult to remove the cast sand remaining in the narrow gap X between the intake passage wall 6a and the injector peripheral wall 8a.

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to provide a cylinder head cooling structure capable of optimizing the shape of the intake port and maintaining the strength.

  The present invention relates to a cylinder head cooling structure in which a water jacket is formed between an intake passage wall surrounding a plurality of intake ports and an exhaust passage wall surrounding a plurality of exhaust ports. An intake port surrounding wall having a real part and integrally surrounding a plurality of intake ports is formed.

  Thus, in the cylinder head cooling structure, since the intake port surrounding wall is formed so as to integrally surround the plurality of intake ports with a solid portion between the plurality of intake ports, it is supplied to the water jacket. The cooling water flows along the intake port surrounding wall and cools around the plurality of intake ports via the intake port surrounding wall. By providing the intake port surrounding wall, the shape of the intake port can be freely selected to be an optimum shape, and the strength around the intake port can be increased.

  In the cylinder head cooling structure, it is preferable that the intake port surrounding wall integrally forms an injector peripheral wall.

  According to the cylinder head cooling structure of the present invention, by providing the intake port surrounding wall, it is possible to increase the intake efficiency by making the intake port into an optimal shape, and further, the intake port surrounding wall increases the strength around the intake port. An excellent effect of being greatly enhanced can be achieved.

  In addition, since the overall volume of the air gap formed between the intake passage wall and the exhaust passage wall can be reduced as compared with the conventional case, and the narrow air gap that has been conventionally provided can be omitted, the casting of the cylinder head There exists an effect which can perform the operation | work for removing the cast sand remaining inside later easily.

It is a cutting | disconnection top view which shows one Example of the cylinder head cooling structure of this invention. It is a cutting side view showing an example of the conventional cylinder head. It is the top view of the conventional water jacket which looked at FIG. 2 from the III-III direction.

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

  FIG. 1 is a cut plan view showing an example of a cylinder head cooling structure of the present invention. Conventionally, as shown in FIG. 3, the intake passage walls 6a and 6b and the exhaust passage walls 7a and 7b that individually surround the plurality of intake ports 2a and 2b and the plurality of exhaust ports 3a and 3b provided in the cylinder head 1, respectively. And the water jacket 4 is formed by a gap such as a narrow gap X formed between them. In the present invention, as shown in FIG. The intake port surrounding wall 12 is provided with a solid portion 11 so as to integrally surround the plurality of intake ports 2a, 2b.

  In other words, in the past, it was considered that the cylinder head 1 was required to be cooled by providing the water jacket 4 in the entire plane direction, but the intake gas was less than the temperature around the exhaust ports 2a and 2b through which the exhaust gas passes. Since the temperature around the intake ports 3a and 3b passing through is low, it has been found that no problem occurs even if the water jacket 4 is not provided close to the intake ports 2a and 2b. Therefore, in the present invention, as described above, the intake port surrounding wall 12 that includes the solid portion 11 between the plurality of intake ports 2a and 2b and integrally surrounds the plurality of intake ports 2a and 2b is provided. The surroundings of 2a and 2b are cooled by one intake port surrounding wall 12.

  At this time, the intake port surrounding wall 12 can cool the injector opening 8 together by integrally forming the injector peripheral wall 8a.

  Next, the operation of the above embodiment will be described.

  As shown in FIG. 1, since the intake port surrounding wall 12 is formed so as to integrally surround the plurality of intake ports 2a, 2b with the solid portion 11 between the plurality of intake ports 2a, 2b, The supplied cooling water W flows along the intake port surrounding wall 12, and the periphery of the intake ports 2 a and 2 b is cooled by the cooling water W through the intake port surrounding wall 12. In addition, when the intake port surrounding wall 12 integrally forms the injector peripheral wall 8a, the periphery of the injector opening 8 is also cooled together.

  As described above, by providing the intake port surrounding wall 12, the shape of the intake ports 2a and 2b can be freely designed, and thus the intake ports 2a and 2b can be optimally shaped. As a result, intake efficiency can be improved, and exhaust gas and fuel consumption can be improved.

  Furthermore, since the strength of the cylinder head 1 is increased by the intake port surrounding wall 12, even when the intake pressure is increased, the strength around the intake ports 2a and 2b can be kept sufficiently high.

  Further, compared to the conventional case, the overall volume of the gap formed between the intake passage walls 6a and 6b and the exhaust passage walls 7a and 7b can be reduced, and the conventional narrow gap X can be omitted. The operation for removing the casting sand remaining inside the cylinder head 1 after casting becomes easy.

  It should be noted that the cylinder head cooling structure of the present invention is not limited to the above-described embodiment, and it is needless to say that various changes can be made without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Intake port 2a, 2b Intake port 3 Exhaust port 3a, 3b Exhaust port 4 Water jacket 6a, 6b Intake passage wall 7a, 7b Exhaust passage wall 8a Injector surrounding wall 11 Solid part 12 Intake port surrounding wall

Claims (2)

  A cylinder head cooling structure in which a water jacket is formed between an intake passage wall surrounding a plurality of intake ports and an exhaust passage wall surrounding a plurality of exhaust ports, and has a solid part between the plurality of intake ports. A cylinder head cooling structure characterized by forming an intake port surrounding wall that integrally surrounds a plurality of intake ports.   2. The cylinder head cooling structure according to claim 1, wherein the intake port surrounding wall integrally forms an injector peripheral wall.

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