JPH04321711A - Cooling device for exhaust manifold - Google Patents

Abstract

PURPOSE:To uniformly lower the temperature of an exhaust manifold extending over from the inlet to the outlet by enlarging cooling effect of the exhaust manifold by cooling water according as gas flows from the inlet to the outlet. CONSTITUTION:An exhaust manifold 1 of four cylinder marine diesel engine 2 is covered with a cooling water jacket 8. Contact area of fins provided on the outer circumference of the exhaust manifold with cooling water flowing in the cooling water jacket 8 is enlarged according to progressing from the inlet 6 to the outlet 7. Hereby cooling effect of the exhaust manifold 1 by cooling water flowing in the cooling water jacket is enlarged following from the inlet 6 to the outlet 7. Accordingly, the temperature of the exhaust manifold 1 can be uniformly lowered extending over from the inlet 6 to the outlet 7.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust manifold cooling system having a cooling water jacket covering the exhaust manifold of an engine.

0002

[Prior Art] An exhaust manifold cooling device is known which is equipped with a cooling water jacket that covers the exhaust manifold of a multi-cylinder engine and cools the exhaust manifold with the cooling water flowing inside the jacket.
Publication No. 32).

0003

[Problems to be Solved by the Invention] If aluminum is used as a material for a multi-cylinder engine, a high-output engine can be made lightweight and compact. However, since aluminum has a large coefficient of thermal expansion, there is a problem in that large thermal stress acts on the connection between the exhaust manifold and the engine body.

[0004] In other words, in an exhaust manifold, the exhaust flow rate increases from the inlet to the outlet.
The outlet temperature is higher than the inlet temperature. In contrast, in conventional exhaust manifold cooling devices, the cooling effect of cooling water on the exhaust manifold is equal from the inlet to the outlet, so the exhaust manifold outlet temperature is higher than the inlet temperature even after cooling. there were. Therefore, a problem arises in that large thermal stress acts on the connection between the outlet side portion of the exhaust manifold and the engine body, causing damage to the connection.

Furthermore, if the outlet side of the exhaust manifold is cooled to a temperature that is not affected by thermal stress, the temperature at the inlet side becomes too low, making it impossible to utilize the exhaust gas energy for an exhaust turbocharger or the like.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exhaust manifold cooling device that can solve the problems of the prior art described above.

[0007]

[Means for Solving the Problems] The first invention is characterized in that in an exhaust manifold cooling device equipped with a cooling water jacket that covers the exhaust manifold of a multi-cylinder engine, , the cooling effect of the exhaust manifold by the cooling water is increased.

[0008] The second invention is characterized in that in an exhaust manifold cooling device equipped with a cooling water jacket that covers the exhaust manifold of a multi-cylinder engine, fins are provided on the outer periphery of the exhaust manifold, and the fins and the cooling water The contact area with the exhaust manifold increases from the inlet to the outlet of the exhaust manifold.

The third aspect of the present invention is characterized in that in an exhaust manifold cooling device including a cooling water jacket covering the exhaust manifold of a multi-cylinder engine, the flow rate of the cooling water in the jacket is higher than that from the inlet of the exhaust manifold. The point is that it gets bigger as you move towards the exit.

[0010] The fourth invention is characterized in that, in an exhaust manifold cooling device including a cooling water jacket covering the exhaust manifold of a multi-cylinder engine, a plurality of cooling water jets are provided in the jacket to jet cooling water toward the exhaust manifold. The cooling water jet flow rate from the exhaust manifold increases from the inlet to the outlet of the exhaust manifold.

[0011]

[Operation] According to the configuration of each of the present inventions, the cooling effect of the exhaust manifold by the cooling water increases from the inlet to the outlet of the exhaust manifold, so that the temperature of the exhaust manifold can be lowered uniformly from the inlet to the outlet. can.

0012

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

The exhaust manifold 1 shown in FIGS. 1 to 3 has the following features:
As shown in FIG. 2, it is connected to a cylinder head 3 of a four-cylinder marine diesel engine 2 made of aluminum. For this connection, the exhaust manifold 1 has connection bolts 4.
A boss 5 is formed for insertion.

The exhaust manifold 1 has the same number of inlets 6 as the number of cylinders of the engine 2 and a single outlet 7, and each inlet 6 communicates with an exhaust port of the cylinder head 3. As a result, the engine 2
Exhaust gas discharged from the inlet 6 of the exhaust manifold 1
It reaches the inside of the exhaust manifold, and is discharged to the outside of the exhaust manifold 1 from the outlet 7.

A cooling water jacket 8 covering the exhaust manifold 1 is provided. A cooler housing 9 is provided below this cooling water jacket 8. The exhaust manifold 1, cooling water jacket 8, and cooler housing 9 are integrally cast. The left side of the cooling water jacket 8 in FIG. 1 is the cooling water inlet 10. Cooling water introduced into the jacket 8 from the inlet 10 by a pump (not shown) flows toward the right in FIG. 1 as indicated by an arrow to cool the exhaust manifold 1. Thereafter, the cooling water is introduced into a cooler 11 provided inside the cooler housing 9. As shown in FIG. 2, the cooler 11 includes a cylindrical outer wall 12 and a large number of pipes 13 arranged inside the outer wall 12. Cooling water that cools the exhaust manifold 1 flows between the outer wall 12 and the pipe 13. Further, seawater is circulated inside the pipe 13 by a pump (not shown). Thereby, the cooling water that cooled the exhaust manifold 1 is cooled by seawater. The cooling water in the exhaust manifold 1 flows in from the inlet 14 of the cooler 11 disposed inside the cooler housing 9 and flows out from the outlet 15, and the seawater inlet and outlet (not shown) to the pipe 13 is connected to the cooler housing 9. located outside.

A plurality of fins 20 are provided on the outer periphery of the exhaust manifold 1. The contact surface 20a of the fin 20 with the cooling water is perpendicular to the flow direction of the cooling water (the left-right direction in FIG. 1). Figure 4
~As shown in FIG. 6, the fins 20 and the cooling water jacket 8
The contact area with the cooling water flowing inside the exhaust manifold 1
It increases in size from the inlet 6 to the outlet 7. As a result, the cooling effect of the exhaust manifold 1 by the cooling water flowing through the cooling water jacket 8 is reduced to
It becomes larger as it goes from the inlet 6 to the outlet 7.

The flow rate of exhaust gas in the exhaust manifold 1 increases from the inlet 6 of the exhaust manifold 1 toward the outlet. Therefore, the temperature of the exhaust manifold 1 increases from the inlet 6 to the outlet 7 unless cooling is performed. On the other hand, according to the above configuration, the cooling effect of the exhaust manifold 1 by the cooling water in the cooling water jacket 8 increases as it goes from the inlet 6 to the outlet 7 of the exhaust manifold, so that the temperature of the exhaust manifold 1 increases from the inlet to the outlet. It can be cooled uniformly over the entire area. Thereby, it is possible to prevent large thermal stress from acting on the boss 5, which is the connecting portion between the exhaust manifold 1 and the cylinder head 3. In addition, the exhaust gas temperature for reducing thermal stress does not drop more than necessary, and exhaust energy can be used effectively to utilize an exhaust turbo supercharger or the like.

7 to 12 show a second embodiment of the present invention. The same parts as in the first embodiment are indicated by the same reference numerals, and differences will be explained. In the second embodiment, a plurality of fins 25 are formed on the outer periphery of the exhaust manifold 1. The contact surface 25a of each fin 25 with the cooling water is parallel to the flow direction of the cooling water in the jacket 8 (the left-right direction in FIG. 7). The contact area of the fins 25 with the cooling water increases from the inlet 6 to the outlet 7 of the exhaust manifold 1, as shown in FIGS. 10 to 12. Thereby, the cooling effect of the exhaust manifold 1 by the cooling water increases from the inlet 6 toward the outlet 7.

In the first and second embodiments described above, the cooling effect of the exhaust manifold 1 by the cooling water was changed by changing the contact area between the fins 20 and 25 and the cooling water. The cooling effect may be changed by increasing the number of fins from the inlet to the outlet.

FIGS. 13 to 18 show a third embodiment of the present invention. The same parts as in the first embodiment are indicated by the same reference numerals, and differences will be explained. In the third embodiment, an inner wall 3 is provided inside the cooling water jacket 8 so as to surround the exhaust manifold 1.
0 is integrally formed. The cross-sectional area of the cooling water passage between the inner wall 30 and the exhaust manifold 1 becomes smaller from the inlet 6 of the exhaust manifold 1 toward the outlet 7, as shown in FIGS. 16 to 18. As a result, the flow rate of the cooling water flowing inside the jacket 8 increases as it goes from the inlet 6 to the outlet 7 of the exhaust manifold 1, and the cooling effect of the cooling water on the exhaust manifold 1 increases as it goes from the inlet 6 to the outlet 7. .

FIGS. 19 to 21 show a fourth embodiment of the present invention. The same parts as in the first embodiment are indicated by the same reference numerals, and differences will be explained. In the fourth embodiment, a guide plate 35 is provided integrally with the cooling water jacket 8 inside the cooling water jacket 8 and above the exhaust manifold 1 . The distance between the guide plate 35 and the exhaust manifold 1 becomes smaller from the inlet 6 to the outlet 7 of the exhaust manifold 1. That is, as shown in FIG.
The distance H1 between the guide plate 35 and the exhaust manifold 1 is the maximum at the position farthest from the exhaust manifold 1, and the distance H2 between the exhaust manifold 1 and the guide plate 35 is the minimum at the position closest to the outlet 7. As a result, the flow rate of the cooling water between the guide plate 35 and the exhaust manifold 1 increases from the inlet 6 to the outlet 7 of the exhaust manifold 1, and the cooling effect of the cooling water on the exhaust manifold 1 increases from the inlet 6 to the outlet 7. It gets bigger as you move towards it.

FIGS. 22 to 24 show a fifth embodiment of the present invention. The same parts as in the first embodiment are designated by the same reference numerals, and differences will be explained. In the fifth embodiment, the cooling water jacket 8
A guide tube 40 is inserted into the inlet 10 of the guide tube 4.
A plurality of spouts 40a, 40b, 40c are formed at 0,
Cooling water reaches the inside of the cooling water jacket 8 from each of the jet ports 40a, 40b, and 40c. Each spout 40a, 40b, 4
0c spouts cooling water toward the exhaust manifold 1,
The opening area of each of the ejection ports 40a, 40b, and 40c increases from the inlet 6 of the exhaust manifold 1 toward the outlet 7. As a result, each spout 40a, 40b, 4
The flow rate of the cooling water ejected from 0c increases as it goes from the inlet 6 to the outlet 7 of the exhaust manifold 1, and the cooling effect of the cooling water on the exhaust manifold 1 increases as it goes from the inlet 6 to the outlet 7.

[0023]

[Effects of the Invention] According to the present inventions, the temperature of the exhaust manifold of the engine can be lowered uniformly from the inlet to the outlet, so that the exhaust manifold and the engine body can be lowered uniformly without absorbing exhaust gas energy unnecessarily. It is possible to reduce the thermal stress acting on the joints of the

[Brief explanation of drawings]

FIG. 1 is a side sectional view of an exhaust manifold cooling device according to a first embodiment of the present invention.

FIG. 2 is a front sectional view of the exhaust manifold cooling device according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional plan view of the exhaust manifold cooling device according to the first embodiment of the present invention.

[Figure 4] Cross-sectional view taken along the line IV-IV in Figure 1

[Figure 5] Cross-sectional view taken along line V-V in Figure 1

[Figure 6] VI-VI line sectional view in Figure 1

FIG. 7 is a side sectional view of an exhaust manifold cooling device according to a second embodiment of the present invention.

FIG. 8 is a front sectional view of an exhaust manifold cooling device according to a second embodiment of the present invention.

FIG. 9 is a cross-sectional plan view of an exhaust manifold cooling device according to a second embodiment of the present invention.

[Figure 10] Cross-sectional view taken along line XX in Figure 7

[Figure 11] Cross-sectional view taken along the line XI-XI in Figure 7

[Figure 12] Cross-sectional view taken along the line XII-XII in Figure 7

FIG. 13 is a side sectional view of an exhaust manifold cooling device according to a third embodiment of the present invention.

FIG. 14 is a front sectional view of an exhaust manifold cooling device according to a third embodiment of the present invention.

FIG. 15 is a cross-sectional plan view of an exhaust manifold cooling device according to a third embodiment of the present invention.

[Figure 16] Cross-sectional view taken along the line XVI-XVI in Figure 13

[Figure 17]
Cross-sectional view taken along the line XVII-XVII in Figure 13

[Figure 18] Figure 13
XVIII-XVIII cross-sectional view of

FIG. 19 is a side sectional view of an exhaust manifold cooling device according to a fourth embodiment of the present invention.

FIG. 20 is a front sectional view of an exhaust manifold cooling device according to a fourth embodiment of the present invention.

FIG. 21 is a cross-sectional plan view of an exhaust manifold cooling device according to a fourth embodiment of the present invention.

FIG. 22 is a side sectional view of an exhaust manifold cooling device according to a fifth embodiment of the present invention.

FIG. 23 is a front sectional view of an exhaust manifold cooling device according to a fifth embodiment of the present invention.

FIG. 24 is a cross-sectional plan view of an exhaust manifold cooling device according to a fifth embodiment of the present invention.

[Explanation of symbols]

1 Exhaust manifold 2 Engine 6 Entrance 7 Exit 8 Cooling water jacket 20, 25 fin 40a, 40b, 40c spout

Claims (4)

[Claims] [Claim 1] In an exhaust manifold cooling device equipped with a cooling water jacket that covers the exhaust manifold of a multi-cylinder engine, the cooling effect of the exhaust manifold by the cooling water increases from the inlet to the outlet of the exhaust manifold. An exhaust manifold cooling device featuring: 2. In an exhaust manifold cooling device equipped with a cooling water jacket that covers the exhaust manifold of a multi-cylinder engine, fins are provided on the outer periphery of the exhaust manifold, and the contact area between the fins and the cooling water is equal to or smaller than that of the exhaust manifold. A cooling device for an exhaust manifold, characterized in that the size increases from the inlet to the outlet. 3. An exhaust manifold cooling device including a cooling water jacket covering the exhaust manifold of a multi-cylinder engine, wherein the flow velocity of the cooling water in the jacket increases from the inlet to the outlet of the exhaust manifold. An exhaust manifold cooling device featuring: 4. An exhaust manifold cooling device including a cooling water jacket that covers the exhaust manifold of a multi-cylinder engine, wherein a plurality of jetting ports for spouting cooling water toward the exhaust manifold are provided in the jacket, and a plurality of jetting ports are provided in the jacket. A cooling device for an exhaust manifold, characterized in that the flow rate of cooling water jetted from the exhaust manifold increases from the inlet to the outlet of the exhaust manifold.