JP2005188352A - Exhaust manifold integrated engine cooling structure - Google Patents

Abstract

The cooling capacity of a cooling structure of an exhaust manifold integrated engine is increased.
A cooling water flow passage from a cylinder block side water jacket to a water jacket provided in a cylinder head is arranged so that the flow rate is increased on one end side of the cylinder row and on the exhaust side, and the other end side of the cylinder row is disposed. A cooling water outlet 4b is provided on the intake side. Suitable for the exhaust manifold where the directivity of the flow of the main cooling water passage flowing from one end side to the other end side in the cylinder row direction is constant, and the temperature becomes high by the sub cooling water passage that starts to flow from the exhaust side and cools around the exhaust manifold Can be cooled to. Since the high temperature around the exhaust manifold is cooled by a separate system from the main cooling water passage, the main and sub cooling water passages are provided side by side, and the parallel flow reduces the resistance of each flow passage. It can be cooled efficiently.
[Selection] Figure 7

Description

  The present invention relates to a cooling structure for an exhaust manifold integrated engine.

Conventionally, there is an automobile engine in which an exhaust manifold is formed on a cylinder head (see, for example, Patent Document 1). In the engine having such a structure, the exhaust manifold can be cooled by the cooling water flowing in the water jacket provided in the cylinder head.
Japanese Examined Patent Publication No. 61-14598 (2nd page, Fig. 2)

  As described above, the exhaust manifold and its collecting part are cooled by flowing cooling water around the exhaust manifold, so that the exhaust manifold can be suitably cooled. However, when the exhaust temperature becomes higher due to higher output Therefore, it is necessary to further increase the cooling capacity. For this purpose, it is conceivable to increase the cooling area, but there is a problem that the water jacket becomes larger and the engine becomes larger.

  In order to solve such a problem and realize a cooling structure of an exhaust manifold integrated engine that can enhance the cooling capacity of an exhaust manifold provided integrally with a cylinder head, in the present invention, a cylinder of a crossflow engine An exhaust manifold (2) having an exhaust assembly (2c) in which a plurality of exhaust branches (2b) and the respective exhaust branches (2b) are assembled inside the head (1), a water jacket (4), Is an exhaust manifold-integrated engine cooling structure formed integrally with the water jacket (4), in which the cooling water flowing in the water jacket (4) flows from the exhaust side of one end in the cylinder row direction toward the other end side of the combustion chamber CL. A main cooling water passage (D) that flows around and an auxiliary cooling water passage (E) that flows around the exhaust manifold (2) are provided.

  An exhaust manifold (2) having a plurality of exhaust branches (2b) and an exhaust collecting part (2c) in which the exhaust branches (2b) are gathered inside a cylinder head (1) of a crossflow engine. And a water jacket (4) integrally formed in the cooling structure of the exhaust manifold-integrated engine, wherein the cylinder block-side water jacket (5) communicates with the water jacket (4). (11a, 11b), and a cooling water inlet (5a) at one end of the cylinder row so that the main cooling water flow in the cylinder block side water jacket (5) makes one round of the cylinder row. And a cooling water outlet (5b) and a partition wall (5c) positioned between the cooling water inlet (5a) and the cooling water outlet (5b) are provided, and the cooling water passage (1 a · 11b) is provided so that the flow rate is increased on the exhaust side on one end side in the cylinder row direction, and the cooling water outlet (4b) of the water jacket (4) of the cylinder head (1) is It is assumed that it is provided on the intake side at the other end side in the cylinder row direction.

  According to the present invention, since the cooling water flowing through the main cooling water passage provided in the cylinder head flows from one end side to the other end side in the cylinder row direction, the directivity of the flow is constant and the cooling water flows from the exhaust side. It is possible to suitably cool the exhaust manifold which becomes high temperature from the start. In addition, by providing a sub-cooling water passage for cooling the exhaust manifold, the high temperature exhaust manifold is cooled by a separate system from the main cooling water passage. Since the resistance of each flow path is reduced by the parallel flow, the exhaust manifold can be efficiently cooled.

  In addition, the cooling water entering the water jacket in the cylinder head is more on the exhaust side on one end side in the cylinder row direction and is discharged from the intake side on the other end side in the cylinder row direction so that the cooling water flows around the exhaust manifold. Will be leaked from. In this way, by defining the directivity of the flow of cooling water in the water jacket in the cylinder head, a smooth flow of cooling is ensured, and most of the cooling water can flow to the exhaust manifold, which is particularly hot. The cooling efficiency can be greatly improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing intake / exhaust paths in a cylinder head of an in-line four-cylinder engine to which the present invention is applied. This engine is a four-valve engine provided with two intake valves and two exhaust valves per cylinder. In addition, it is not limited to an in-line 4-cylinder or 4-valve engine, and the number of other cylinders, the cylinder arrangement, and the number of valves may be different.

  As shown in the figure, an exhaust manifold 2 is formed inside the cylinder head 1. The exhaust manifold 2 includes a pair of exhaust branch passages 2a communicating with a pair of exhaust valve ports of a cylinder, an exhaust branch passage 2b having a pair of exhaust branch passages 2a, and the same number of exhaust branch passages 2b as the number of cylinders. And an exhaust collecting portion 2c, which are formed into one, and are formed inside the cylinder head 1 as shown in the figure. As shown in FIG. 2, the exhaust collecting portion 2c is opened on the side surface of the cylinder head 1, and the external exhaust pipe 3 is connected to the opening. In addition, although the exhaust manifold 2 is drawn flat in the drawing, it is actually formed in three dimensions.

  Since the exhaust gas flows through the exhaust manifold 2, it is necessary to cool the exhaust manifold 2. The cooling can be performed by providing a part of the water jacket provided in the cylinder head 1 also around the exhaust manifold 2.

  The water jacket in the engine of the illustrated example has a shape as shown in FIG. The shape shown in FIG. 3 schematically shows the outer shape of each of the water jackets 4 and 5 formed in the cylinder head 1 and the cylinder block (not shown). The water jacket 5 on the cylinder block side has a wave shape and an oval annular shape as a whole so as to surround each cylinder. A cooling water inlet 5a to the water jacket 5 is provided at one end in the direction of the cylinder row, and a cooling water outlet 5b is provided at an opposing position across the corresponding cylinder.

  Further, a separator (formed by protruding a part of the cylinder block into the water jacket 5 as a partition wall) 5c is provided between the cooling water inlet 5a and the cooling water outlet 5b in the water jacket 5, and the cooling water inlet The flow rate of the cooling water flowing in the shorter direction between 5a and the cooling water outlet 5b is limited to be small. As a result, most of the cooling water flowing in from the cooling water inlet 5a flows around all the cylinders as indicated by an arrow A in the figure. A part of the cooling water can flow from the part not blocked by the separator 5c to the cooling water outlet side as indicated by an arrow B in the figure.

  The cylinder block side water jacket 5 and the cylinder head side water jacket 4 communicate with each other via a coolant passage provided in a gasket (not shown) sandwiched between the cylinder block and the cylinder head 1. As shown in FIG. 4, many cooling water passages 11a and 11b are arranged on one end side of the cylinder row where the cooling water inlet 5a and the cooling water outlet 5b are provided. Further, the opening area of the cooling water passage 11a provided on one end side of the cylinder row is made wider than that of the other cooling water passages 11b. A part of the cooling water in the cylinder block side water jacket 5 flows to the cylinder head side water jacket 4 through these cooling water passages 11a and 11b (arrow C). The cooling water flowing into the water jacket 4 cools around the combustion chamber and flows out from a plurality of cooling water outlets 4b provided on the side opposite to the side provided with the cooling water passage 11a in the cylinder row direction.

  In the illustrated example, as shown in FIG. 1, an exhaust manifold cooling water jacket 6 for cooling the exhaust manifold 2 around the exhaust collecting portion 2c is provided. The exhaust manifold cooling water jacket 6 is defined and formed by a portion recessed in the cylinder head 1 and a lid member 7. When casting the cylinder head 1, the water jacket 6 for cooling the exhaust manifold can be formed together. For example, the core of the water jacket 6 is set simultaneously with the core of the exhaust manifold 2, or the exhaust manifold After setting the two cores, the core of the water jacket 6 can be set. Therefore, since the cylinder head 1 can be manufactured in substantially the same manner as the case where the exhaust manifold cooling water jacket 6 is not provided, the productivity reduction due to the provision of the water jacket 6 in the cylinder head 1 does not occur.

  A pair of left and right openings 7 are provided on the side wall surface of the cylinder head 1 as insertion / extraction holes for the core of the exhaust manifold cooling water jacket 6 as shown in FIG. A lid member 8 is attached to these openings 7. Further, a cooling water inlet 6a communicating with the cylinder head side water jacket 4 is provided on one end side in the longitudinal direction of the water jacket 6 (right side in FIG. 1), and attached to the lid member 8 on the other end side (left side in FIG. 1). The hose plug 9 is provided with a cooling water outlet so that the cooling water flows from the one end side toward the other end side.

  The exhaust manifold cooling water jacket 6 is provided with rib-shaped partitions 10 formed integrally with the cylinder head 1 at intermediate portions between the exhaust collecting portion 2 c and the left and right openings 7. Further, the central portion in the longitudinal direction of the water jacket 6 is narrowed to open the exhaust collecting portion 2c to the outside. Each partition 10 extends in a direction crossing a linear flow path from the cooling water inlet 6 a to the cooling water outlet (9) in the water jacket 6, and is formed by a portion where the exhaust collecting portion 2 c is formed in the water jacket 6. The water jacket 6 extends from one end in the width direction toward the other end so as to make the side opposite to the side that is made thinner. Thereby, the flow path of the water jacket 6 is formed to meander.

  Therefore, the flow of the cooling water flowing from one end side to the other end side in the longitudinal direction of the exhaust manifold cooling water jacket 6 is as shown by the arrows in FIG. 5 and the portions where the left and right partitions 10 and the exhaust collecting portion 2c are formed. The flow becomes meandering. Since the cooling water flow path meanders in this way, in the exhaust manifold cooling water jacket 6, the flow path length of the cooling water is increased, the contact area with the exhaust manifold 2 is increased, and the cooling performance with respect to the exhaust manifold 2 is improved. improves.

  On the other hand, when the partition 10 is not provided, in the water jacket 16 as shown in FIG. 6, the flow of the cooling water flows from the cooling water inlet 6a to the cooling water outlet (9) as shown by the arrows in the figure. It flows in a straight line and partly circulates through the wide portions at both ends. For this reason, in the wide portion of the water jacket 16, a portion in which the cooling water stays in a part (particularly the corner) is generated, and the cooling performance is deteriorated.

  On the other hand, according to the structure provided with the partition 10, the flow in the water jacket 6 can be made uniform because the meandering flow flows with respect to the wide portion of the water jacket 6. Further, the cooling performance around the exhaust collecting portion 2c is further improved such that the cooling water does not stay in the corner portion.

  An air vent hole 6b is provided on each upper side of the cooling water inlet 6a and the cooling water outlet (9) in the water jacket 6 for exhaust manifold cooling. The air vent hole 6b has a smaller diameter than the cooling water inlet 6a and the cooling water outlet (9), and the main cooling water flow in the water jacket 6 is between the cooling water inlet 6a and the cooling water outlet (9). To be. Thereby, the flow in the cylinder head side water jacket 4 is also mainly composed of the lower cooling water inlet 6a, which is advantageous for cooling the combustion chamber.

  Although the cooling water outlet is the hose plug 9 attached to the lid member 8 in the illustrated example, it may be communicated with the cylinder head side water jacket 4 in the same manner as the cooling water inlet 6a. This eliminates the need for extra external piping members and piping work, and can reduce the manufacturing cost. Further, in the processing of the cooling water inlet 6a and the air vent hole 6b, and the cooling water outlet communicating with the cylinder head side water jacket 4, they can be provided at positions corresponding to the respective openings 7. It is possible to easily remove the sand and to attach the lid member 8 after drilling.

  Further, as shown in FIG. 5, cooling water is provided between the boss 12 provided with a bolt hole into which a bolt (not shown) for attaching the external exhaust pipe (exhaust part) 3 to the cylinder head 1 is screwed and the exhaust collecting portion 2c. By providing the communication passage 13 through which the shaft flows, it is possible to suitably prevent a reduction in the axial force due to the heat of the bolt.

  According to the present invention, as described above, the cooling water passages 11a and 11b for flowing the cooling water from the cylinder block side water jacket 5 to the cylinder head side water jacket 4 are many on one end side in the cylinder row direction, and the opening area is large. Has been. Therefore, the cooling water flowing into the cylinder head side water jacket 4 is concentrated on one end side in the cylinder row direction, and a main cooling water flow path (arrow D in FIG. 7) that flows from one end side of the cylinder row toward the other end side is formed. .

  Further, as shown in FIG. 4, the cooling water passage 11a having a large opening area is disposed on the exhaust side on one end side in the cylinder row direction, and a large amount of cooling water flows out from the exhaust side. Therefore, a large amount of cooling water also flows on the exhaust side of the water jacket 4, and a sub-cooling water flow path for suitably cooling around the exhaust manifold 2 is formed as indicated by an arrow E in FIG. Thereby, the cooling efficiency with respect to the exhaust manifold 2 which becomes high temperature improves.

  In this way, a flow of cooling water (arrow E) for cooling the exhaust manifold portion is secured in parallel with a flow of cooling water (arrow D) for cooling the combustion chamber (imaginary line in FIG. 7) CL portion. (See FIG. 8). In the case of the conventional type cooling structure in which they are connected in series, the flow resistance increases and the cooling school decreases, or a negative pressure portion is generated in the flow path, and the cooling effect is greatly reduced by cavitation. However, since the resistance of each flow path is reduced by the parallel flow, the cooling effect can be prevented from decreasing.

  This is particularly effective in an engine in which a separator 5c is provided in the cylinder block-side water jacket 5 so that the flow of cooling water makes one round of the entire cylinder row. As a result, it is possible to eliminate the portion where the cooling water stays in each cylinder, and to specify the start of flow in the cylinder head side water jacket 4. From the exhaust side on one end side of the cylinder row as in the illustrated example, By starting to flow, it is easy to place a flow path around the exhaust manifold along with a flow path around the combustion chamber, and the cooling effect is enhanced.

  With the above structure, the water jacket 4 in the cylinder head 1 of the present invention can be formed by a conventional method for manufacturing a water jacket in a cylinder head, and external piping can be configured in the same manner. And manufacturing costs can be reduced.

  Note that the present invention can also be applied to a marine vessel propulsion engine such as an outboard motor having a vertical crankshaft.

  The exhaust manifold-integrated engine cooling structure according to the present invention has a high cooling effect on the exhaust manifold provided in the cylinder head, and is an engine cooling structure in which a collection portion of the exhaust manifold is provided inside the cylinder head. Useful.

It is a figure which shows the intake / exhaust path in the cylinder head of the in-line 4 cylinder engine to which this invention was applied. It is the end elevation seen along the arrow II-II line of FIG. It is a perspective view showing roughly each water jacket of a cylinder head and a cylinder block. It is a top view which shows a cylinder block side water jacket. It is a figure which shows the flow of the cooling water of the water jacket for exhaust manifold cooling. It is a figure corresponding to FIG. 4 when not providing a partition. It is a top view which shows a cylinder head side water jacket. It is explanatory drawing which shows the flow of the cooling water in this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cylinder head 2 Exhaust manifold, 2b Exhaust branch, 2c Exhaust collecting part 4 Water jacket, 4b Cooling water outlet 5 Cylinder block side water jacket 5a Cooling water inlet, 5b Cooling water outlet, 5c Separator (partition wall)
6 Water jacket for exhaust cooling, 6a Cooling water inlet 11a, 11b Cooling water passage D Main cooling water passage E Sub cooling water passage

Claims (2)

An exhaust manifold integrated engine in which a water jacket is integrally formed with an exhaust manifold having a plurality of exhaust branches and an exhaust collecting portion in which the exhaust branches are gathered inside a cylinder head of a crossflow engine. A cooling structure,
The water jacket includes a main cooling water passage in which cooling water flowing through the inside of the water jacket flows around the combustion chamber from the exhaust side to the other end side at one end in the cylinder row direction, and a sub-cooling configured to flow around the exhaust manifold. A cooling structure for an exhaust manifold-integrated engine, comprising a cooling water passage. An exhaust manifold integrated engine in which a water jacket is integrally formed with an exhaust manifold having a plurality of exhaust branches and an exhaust collecting portion in which the exhaust branches are gathered inside a cylinder head of a crossflow engine. A cooling structure,
A cylinder block water jacket has a cooling water passage communicating with the water jacket;
A cooling water inlet and a cooling water outlet, and a cooling water inlet and a cooling water outlet are provided at one end of the cylinder row so that the main cooling water flow in the cylinder block-side water jacket makes one round of the cylinder row. A partition located between,
The cooling water passage is provided so that the flow rate is increased on the exhaust side on one end side in the cylinder row direction, and the cooling water outlet of the water jacket of the cylinder head is on the intake side on the other end side in the cylinder row direction An exhaust manifold-integrated engine cooling structure characterized by being provided in the engine.

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