JP2017040175A - Cooling structure of cylinder head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the cooling efficiency of a cylinder head.SOLUTION: In a cooling structure of a cylinder head 1, a plurality of cylinders 11A to C are arranged in series in the longitudinal direction of an engine, exhaust ports 12A, B are arranged in the cylinders 11A to C along the longitudinal direction of the engine, and head bolt boss parts 15 are provided on an exhaust side between the cylinders 11A to C. The cooling structure includes: cooling water introduction parts 25 provided under the exhaust ports 12A, B to introduce cooling water supplied from a cylinder block side into the cylinder head 1; first cooling water flow channels 26 branched from the cooling water introduction parts 25 to extend between a pair of the exhaust ports 12A, B; at least one or more second cooling water flow channels 27A, B branched from the cooling water introduction parts 25 to flow in the vicinity of the head bolt boss parts 15; and projection parts 30A, B provided projectingly into the cooling water introduction parts 25 with a prescribed projection amount to squeeze flow channels from the cooling water introduction parts 25 to the second cooling water flow channels 27A, B.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cooling structure for a cylinder head.

  In general, since the contact surface of the cylinder head is likely to be hot, a cooling structure is adopted in which a cooling water flow path is provided around the exhaust port and the injector boss to reduce the temperature of the cylinder head.

  For example, in Patent Document 1, in a cylinder head having a pair of exhaust ports in each cylinder, exhaust gas extending between the exhaust ports is supplied to supply cooling water between exhaust ports that are likely to become the highest temperature or in the vicinity of an injector boss. A cooling structure for a cylinder head having a flow path between ports is disclosed.

JP-A-2015-113706

  Generally, the cooling water supplied to the cylinder head is introduced from a water jacket in the cylinder block to a cooling water introducing portion formed below the exhaust port of the cylinder head. The cooling water introduction section is connected to a flow path between exhaust ports, a head bolt boss side flow path that flows in the vicinity of the head bolt boss section, and the like. In such a flow path structure, the cooling water introduced from the cylinder block to the cooling water introducing section flows into the flow path beside the head bolt boss without being supplied to the flow path between the exhaust ports where the temperature is high. The cooling efficiency may be reduced.

  An object of the disclosed cooling structure is to improve the cooling efficiency of the cylinder head by effectively ensuring the cooling water flow rate from the cooling water introduction part of the cylinder head to the flow path between the exhaust ports.

  In the disclosed cooling structure, a plurality of cylinders are arranged in series in the longitudinal direction of the engine, a pair of exhaust ports are arranged along the longitudinal direction of the engine, and a head is disposed on the exhaust side between the cylinders. A cooling structure for a cylinder head provided with a bolt boss part, the cooling water introduction part being provided below the exhaust port for introducing cooling water supplied from the cylinder block side into the cylinder head, A first cooling water flow path branched from the cooling water introduction section and extending between the pair of exhaust ports; and at least one second cooling water flow branched from the cooling water introduction section and flowing in the vicinity of the head bolt boss section. And a projecting portion that protrudes from the cooling water introduction portion by a predetermined amount and narrows the flow path from the cooling water introduction portion to the second cooling water flow passage.

  A region in which the protrusion extends from the upper flow path wall of the cooling water introduction part to the bottom of the cylinder head and the first cooling water flow path branches in the cooling water introduction part; 2 You may interrupt | block to the area | region where a cooling water flow path branches.

  The cooling water introduction part is provided below the exhaust port in the longitudinal direction of the engine, the first cooling water flow path is provided branched from the longitudinal center of the cooling water introduction part, and the two second A cooling water flow path is provided by branching from both ends in the longitudinal direction of the cooling water introduction part, and the two protrusions are respectively provided from two places between the longitudinal center of the cooling water introduction part and both longitudinal ends. It may be provided protruding.

  According to the disclosed cooling structure, the cooling efficiency of the cylinder head can be improved by effectively ensuring the cooling water flow rate from the cooling water introduction part of the cylinder head to the flow path between the exhaust ports.

(A) is the typical bottom view which looked at a part of cooling structure of the cylinder head concerning a first embodiment from the lower part (cylinder block side), (B) is an AA line sectional view of (A). It is. (A) is the typical bottom view which looked at a part of cooling structure of the cylinder head concerning a second embodiment from the lower part (cylinder block side), (B) is an AA line sectional view of (A). It is. It is the typical bottom view which looked at the flow of the cooling water of the cooling structure of the cylinder head concerning other embodiments from the lower part (cylinder block side).

  Hereinafter, a cylinder head cooling structure according to each embodiment of the present invention will be described with reference to the accompanying drawings. The same parts are denoted by the same reference numerals, and their names and functions are also the same. Therefore, detailed description thereof will not be repeated.

[First embodiment]
1A and 1B are views for explaining a cooling structure of a cylinder head according to the first embodiment. The cooling structure of this embodiment is applied to a multi-cylinder in-line engine in which a plurality of cylinders are arranged in series in the longitudinal direction (crankshaft direction) of the engine.

  Each cylinder 11A-C of the cylinder head 1 has a pair of exhaust ports 12A and B that accommodate two exhaust valves (not shown) and a pair of intake ports 13A and B that respectively contain two intake valves (not shown). (Shown only in FIG. 1A) are opposed to each other with an interval therebetween. An injector boss portion 14 (shown only in FIG. 1A) for installing an injector (not shown) is provided between the intake ports 13A and B facing the exhaust ports 12A and B.

  Between the cylinders 11A to 11C on the exhaust side of the cylinder head 1, exhaust side head bolt boss portions 15 for inserting head bolts (not shown) are provided at intervals. In addition, an intake side head bolt boss portion 16 (shown only in FIG. 1A) for inserting a head bolt (not shown) is spaced between the respective cylinders 11A to 11C on the intake side of the cylinder head 1. Is provided.

  On the intake side of the cylinder head 1, an intake side cooling water flow path 20 (shown only in FIG. 1A) extending in the vicinity of the intake ports 13A, B along the longitudinal direction of the engine (hereinafter also referred to as the vertical direction) is provided. Is provided. A cooling water outlet (not shown) for returning the cooling water to a radiator (not shown) is provided at the downstream end of the intake-side cooling water channel 20.

  On the exhaust side of the cylinder head 1, there is provided an exhaust-side cooling water passage 21 (shown only in FIG. 1B) extending above the exhaust ports 12A and B along the longitudinal direction of the engine. The downstream side of the exhaust-side cooling water passage 21 is connected to the cooling water outlet (not shown) described above.

  Between the cylinders 11A to 11C of the cylinder head 1, an inter-cylinder cooling water flow path 23 extending along the short direction (lateral direction) of the engine is provided. The inter-cylinder cooling water passage 23 is formed so as to branch off from the head bolt boss side cooling water passages 27A and B, the details of which will be described later, and the downstream end thereof joins the intake-side cooling water passage 20.

  Between the exhaust ports 12A, B and the intake ports 13A, B of the cylinder head 1, an intake / exhaust port cooling water flow path 24 (shown only in FIG. 1A) extending in the longitudinal direction of the engine is provided. . The cooling water flow path 24 between intake and exhaust ports branches from the downstream end of the cooling water flow path 26 between exhaust ports, the details of which will be described later, and flows between the intake and exhaust ports 12A and flows between the intake port 13A and the exhaust port 12A. The passage 24A and the cooling water flow path 24B between the second intake and exhaust ports flowing between the intake port 13B and the exhaust port 12B are configured.

  Below each exhaust port 12A, B of the cylinder head 1, a cooling water introduction part 25 for introducing cooling water into the cylinder head 1 from a water jacket of a cylinder block (not shown) is provided in the longitudinal direction of the engine. . The cooling water introducing portion 25 is provided with flow passage restricting protrusions 30A and 30B, the details of which will be described later.

  Between the exhaust ports 12A and 12B of the cylinder head 1, an inter-exhaust-port cooling water flow path (first cooling water flow path) 26 extending in the short direction of the engine is provided. The inter-exhaust-port cooling water flow path 26 is formed so as to branch from substantially the center in the longitudinal direction of the cooling water introducing portion 25 and to have its downstream end merged with the inter-intake / exhaust-port cooling water flow path 24 in the vicinity of the injector boss portion 14. ing.

  Between each exhaust port 12A, B of the cylinder head 1 and the exhaust side head bolt boss part 15, a pair of branches branching from both longitudinal ends of the coolant introduction part 25 and extending in the vicinity of the exhaust side head bolt boss part 15. Head bolt boss side cooling water flow paths (second cooling water flow paths) 27A, B are provided. The head bolt boss side cooling water flow paths 27 </ b> A and B are formed so as to merge with the upstream end of the inter-cylinder cooling water flow path 23, and the downstream end thereof merges with the exhaust-side cooling water flow path 21.

  Above the inter-exhaust-port cooling water flow path 26, an exhaust-side supply flow path 28 (FIG. 1) extends upward from the inter-exhaust-port cooling water flow path 26 and has its downstream end merged with the exhaust-side cooling water flow path 21. (Shown only in (B)).

  The flow restricting protrusions 30A and B are provided so as to protrude in the cooling water introduction part 25 from the exhaust ports 12A and B toward the lower side by a predetermined protrusion amount. A predetermined gap is secured between the projecting ends of the flow restricting protrusions 30A and 30B and the lower inner wall surface of the cooling water introducing part 25, and the flow restricting protrusions 30A and 30B are appropriately projected appropriately. By setting the amount, the cooling water flow rate from the cooling water introduction part 25 to the head bolt boss side cooling water flow paths 27A, B can be adjusted.

  As described above in detail, according to the cooling structure according to the first embodiment, the amount of protrusion of the flow path restricting protrusions 30A and 30B is appropriately set to an optimum value, By restricting the flow path to the cooling water flow paths 27A and 27B, it becomes possible to effectively secure the flow rate of the cooling water supplied to the cooling water flow path 26 between the exhaust ports, and to improve the cooling efficiency of the cylinder head 1. Can do.

[Second Embodiment]
2A and 2B are views for explaining a cooling structure of the cylinder head according to the second embodiment. The cooling structure of the second embodiment is obtained by replacing the flow restrictor protrusions 30A, B of the first embodiment with flow passage blocking protrusions 31A, B. Since other configurations are substantially the same as those of the first embodiment, detailed description thereof is omitted.

  The flow passage blocking projections 31A and 31B are provided so as to protrude downward from the flow passage wall on the exhaust port 12A and B side of the cooling water introduction portion 25 to the bottom of the cylinder head 1. That is, the flow path blocking projections 31A and 31B branch the inside of the cooling water introduction part 25 into the central region in the longitudinal direction that branches from the inter-exhaust-port cooling water flow path 26 and the head bolt boss side cooling water flow paths 27A and B. It is configured so as to be completely blocked by the regions at both longitudinal ends.

  Thereby, the flow of the cooling water from the cooling water introduction part 25 to the head bolt boss side cooling water flow paths 27A and 27B is completely blocked, and the cooling water flow rate of the cooling water flow path 26 between the exhaust ports is effectively increased. Therefore, the cooling efficiency of the cylinder head 1 can be improved with certainty.

  The present invention is not limited to the above-described embodiments, and can be appropriately modified and implemented without departing from the spirit of the present invention.

  For example, as shown in FIG. 3, the cooling water flow direction of the cooling water flow path 26 between the exhaust ports may be configured to flow in the opposite direction.

DESCRIPTION OF SYMBOLS 1 Cylinder head 11A-C Cylinder 12A, B Exhaust port 13A, B Intake port 14 Injector boss part 15 Exhaust side head bolt boss part 16 Intake side head bolt boss part 20 Intake side cooling water flow path 21 Exhaust side cooling water flow path 23 Between cylinders Cooling water flow path 24 Cooling water flow path between intake / exhaust ports 25 Cooling water introduction part 26 Cooling water flow path between exhaust ports 27A, B Head bolt boss side cooling water flow path 28 Exhaust side supply flow path 30A, B Flow path restricting projections 31A, B Channel blocking projection

Claims (3)

A plurality of cylinders are arranged in series in the longitudinal direction of the engine, a pair of exhaust ports are arranged along the longitudinal direction of the engine, and a head bolt boss portion is provided on the exhaust side between the cylinders. A cylinder head cooling structure,
A cooling water introduction section that is provided below the exhaust port and introduces cooling water supplied from the cylinder block side into the cylinder head;
A first cooling water flow path branched from the cooling water introduction section and extending between the pair of exhaust ports;
At least one second cooling water flow path branched from the cooling water introduction section and flowing in the vicinity of the head bolt boss section;
A cooling structure for a cylinder head, comprising: a protruding portion that protrudes from the cooling water introduction portion to the second cooling water flow passage, and protrudes from the cooling water introduction portion into the cooling water introduction portion. A region in which the protrusion extends from the upper flow path wall of the cooling water introduction part to the bottom of the cylinder head and the first cooling water flow path branches in the cooling water introduction part; The cooling structure for a cylinder head according to claim 1, wherein the cooling structure is cut off at a region where the cooling water flow path branches. The cooling water introduction portion is provided in the longitudinal direction of the engine below the exhaust port;
The first cooling water flow path is branched from the longitudinal center of the cooling water introduction part;
Two of the second cooling water flow paths are provided to be branched from both longitudinal ends of the cooling water introduction part,
The cylinder head cooling structure according to claim 1 or 2, wherein the two protrusions are provided so as to protrude from two locations between a longitudinal center of the cooling water introduction portion and both longitudinal ends.

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