JPH0343364Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention relates to an exhaust manifold used in a multi-cylinder internal combustion engine such as a V-type multi-cylinder (for example, 16-cylinder) diesel engine, and particularly relates to an exhaust manifold used in a multi-cylinder internal combustion engine such as a V-type multi-cylinder (for example, 16-cylinder) diesel engine. It is intended for exhaust manifolds of the type in which the tubes are surrounded by an outer wall and the space between the passage tubes and the outer wall forms a cooling water jacket.

[Prior Art] The above-mentioned type of exhaust manifold is widely used in marine internal combustion engines, and the exhaust manifold is cooled and silenced by cooling water.
Such exhaust manifolds are traditionally constructed of cast iron, with an outer wall and internal exhaust passage pipes,
Furthermore, a connecting pipe connecting the inlet of the exhaust passage pipe and the exhaust outlet of the cylinder is integrally formed on the outside of the outer wall.

[Problems to be solved by the invention] However, cast iron exhaust manifolds have the disadvantage of being heavy. Of course, forming the exhaust manifold with a cast product of lightweight metal such as aluminum can eliminate these drawbacks to some extent, but
In that case, the following problems occur.

In other words, in an engine with a large number of cylinders such as a V-type 16-cylinder engine, the number of exhaust passage pipes arranged inside the outer wall of each of the two pairs of exhaust manifolds increases, so due to the constraints of casting work, it is necessary to There are places where it is impossible to provide a space for a cooling water jacket between two exhaust passage pipes, and in such places the two exhaust passage pipes share a pipe wall portion. As a result, each exhaust passage pipe cannot be cooled in its entirety in an optimal state, and if the exhaust manifold is cooled with a cast product such as aluminum, there is a risk that cracks may occur in the passage pipe due to heat.

Of course, in general, not only cast iron products but also exhaust manifolds with a large number of cylinders, the number of passage pipes disposed inside the outer wall increases, so there is also the problem that there are many restrictions on casting or die casting operations.

The present invention aims to solve the above-mentioned problems.

[Means for Solving the Problems] In order to solve the above problems, the present invention provides a plurality of exhaust outlets arranged in series on the outer surface portion of a cylinder assembly including a plurality of cylinders, and an area where the exhaust outlets are installed. An elongated exhaust manifold is arranged along the exhaust manifold, and the exhaust manifold has a strip-shaped base plate portion extending along the installation area in a position facing the outer surface portion, and a base plate portion located on the opposite side of the cylinder assembly across the base plate portion. an exhaust passage pipe, a peripheral wall portion surrounding the installation space of the exhaust passage pipe, and a plurality of connecting pipes disposed between the outer surface portion and the base plate portion and connecting the exhaust outlet to the entrance of the passage pipe. , Installation for fixing the inlet end of the passage pipe to the base plate, fixing a pair of edges of the peripheral wall to both edges in the longitudinal direction of the base plate, and fixing the connecting pipe to the base plate. It is characterized by having a seat.

[Example] In FIG. 1, the illustrated engine is a V-type 16-cylinder engine, and is equipped with a pair of cylinder assemblies 1 in a generally symmetrical positional relationship across a vertical engine center plane O-O. . In each cylinder assembly 1, eight cylinders (only one is shown) are arranged in series along a crankshaft center line Q (indicated by dots in FIG. 1). In each cylinder assembly 1, the cylinder center plane R including the center lines of eight cylinders is at an angle of, for example, 45° with respect to the engine center plane O-O.
is tilted by an angle of 2 is cylinder assembly 1
More specifically, it is a surface extending generally along the cylinder center plane R on the side away from the engine center plane OO of the cylinder assembly 1. An exhaust manifold 3 is arranged obliquely below and outside the outer surface 2 of the cylinder head.

FIG. 2 is a cross-sectional view of FIG. 1, and as is clear from FIGS. The exhaust passage pipe 6 has half the number of cylinders, one peripheral wall portion 7, and eight connecting pipes 8 (the same number as the number of cylinders in each cylinder assembly 1). Each of the above-mentioned parts is made of aluminum products to reduce weight, except for the connecting pipe 8, and only the connecting pipe 8 is made of cast iron product to improve heat resistance.

The base plate portion 5 is formed of a band-like member,
It extends parallel to the cylinder outer surface 2.

The passage pipe 6 is connected to the cylinder outer surface 2 with the base plate portion 5 in between.
The position opposite to the exhaust manifold 3 extends generally in the longitudinal direction of the exhaust manifold 3. As mentioned above, four passage pipes 6 are provided, and they are spaced apart from each other over substantially the entire length. Furthermore, as is clear from FIG. 2, each passage pipe 6 has an inlet portion 1 at one end and a midway portion
0. As will be described later, the inlet portion 10 is fixed to the base plate portion 5, and its inlet opening is connected to an exhaust outlet 11 of the engine body via a connecting pipe 8. Of course, eight exhaust outlets 11 are provided on the outer surface 2 of the cylinder head of each cylinder assembly 1, and are arranged in series in the longitudinal direction of the crankshaft.

The peripheral wall portion 7 is a plate-like member having a curved cross-sectional shape, and surrounds the installation space of the four passage pipes 6 from the outside with a gap between them. As shown in FIG. 2, cooling water ports 12, 13, and 14 are provided at both ends and an intermediate portion of the peripheral wall portion 7. The cooling water port 12 is provided on one end wall of the peripheral wall portion 7 and is connected to a cooling water passage (not shown). The cooling water ports 13 and 14 are connected to the peripheral wall portion 7, respectively.
A pair of cooling water ports 13 and 14 are provided at two locations, upper and lower, depending on the installation orientation of the peripheral wall 7, which will be described later.
One of the cooling water ports 13 and 14 is closed by a blind lid, and the other cooling water ports 13 and 14 are connected to an external cooling water passage. These external cooling water passages allow cooling water ports 12, 1
3 and 14, cooling water is supplied to and discharged from the space 15 in the peripheral wall 7 (the space between the passage pipe 6 and the peripheral wall 7).

Further, a mounting seat 16 is formed on the peripheral wall portion 7 at the end opposite to the cooling water port 12. An exhaust communication pipe is fixed to the mounting seat 16 with bolts, and a passage outlet in each exhaust passage pipe 6 is connected to the exhaust turbine of the supercharger via the exhaust communication pipe or the like.

As described above, cooling water is introduced into the space 15, thereby cooling the exhaust gas flowing inside the passage pipe 6. In the illustrated embodiment, in order to prevent the exhaust gas from being overcooled by the cooling water, all or A portion of some of the passage pipes 6 (for example, a portion 17 indicated by broken line hatching in FIG. 2) is subjected to heat insulation treatment. Such a heat-insulating portion 17 is formed, for example, by applying a ceramic material to the outer surface of the passage pipe 6.

Next, the mounting structure of each of the above parts will be explained.

As mentioned above, the base plate part 5 is a flat strip plate whose width L (FIG. 2) is constant over its entire length, and whose both side edges 20 extend parallel to each other and directly. The base plate part 5 is provided with eight inlet holes 21 at intervals in the longitudinal direction, and the outer periphery of the tip of the inlet part 10 of each passage pipe 6 is fitted into the inlet hole 21 and fixed by welding. There is. Although the peripheral wall portion 7 has a curved cross-sectional shape as described above, a pair of edges extending in the longitudinal direction are parallel and straight to each other, and the edges meet the side edges 20 of the base plate portion 5. It is tightly engaged with and fixed by welding.

In the actual assembly work, after the four passage pipes 6 are fixed to the base plate part 5 by welding as described above,
The peripheral wall portion 7 is fitted into the base plate portion 5. The fitting work is carried out on the assembly of the base plate part 5 and the passage pipe 6, with the mounting seat 16 at the top and the peripheral wall part 7 pointed at the arrow mark in FIG.
After fitting, the side edge 20 and the edge that engages with it are welded. After installing the peripheral wall portion 7 in this manner, the exhaust communication pipe is fixed to the mounting seat 16. Furthermore, before or after attaching the peripheral wall section 7, the connecting pipe 8 is fixed to the base plate section 5 in the following manner.

The connecting pipe 8 is a short tubular member extending from the cylinder outer surface 2 to the base plate part 5, and has flanges 25 at both ends.
It is equipped with 26. As shown in FIGS. 3 and 4, the flanges 25 and 26 are provided with a plurality of bolt insertion holes 27 and 28, and the flanges 26 are inserted into the base plate portion 5 by bolts (not shown) inserted through the bolt insertion holes 28. is fixed to the periphery of the inlet opening. Of course, the flange 25 is connected to the cylinder outer surface 2 around the exhaust outlet 11 (FIG. 1) by the bolt 30 (only the center line shown) inserted into the bolt insertion hole 27.
Fixed.

Each of the exhaust manifolds 3 described above is attached to the left and right cylinder assemblies 1 in an upside-down attitude. More specifically, the left and right exhaust manifolds 3 have the same structure except for the mounting position of the connecting pipe 8, which will be described later, and the mounting seat 16 is located on the side opposite to the flywheel of the engine.
Since the exhaust manifold 3 is mounted in a position facing the cylinder outer surface 2, for example, the part forming the upper part of the exhaust manifold 3 on the right side forms the lower part of the exhaust manifold 3 on the left side.

In this way, the vertical positional relationship of the left and right exhaust manifolds 3 is reversed, so if the mounting position of the connecting pipe 8 with respect to the base plate part 5 is the same for both exhaust manifolds 3, the connection between the left and right exhaust manifolds 3 will be reversed. The attitude of the tube 8 is also upside down.
However, as shown in FIG. 3, the screw holes 31 for the bolts 30 provided in the cylinder assembly 1 are asymmetrical in both the vertical and horizontal directions.
The connecting pipe 8 cannot be fixed to the cylinder assembly 1 in such an upside-down position. for that,
The illustrated embodiment has the following features.

3 is a view in the direction of the arrows in FIG. 1, and FIG. 4 is a view in the direction of the arrows in FIG. Therefore, Figures 3 and 4
In the figure, arrow A indicating the side opposite to the flywheel is reversed left and right.

As is clear from these figures, each exhaust outlet 1
1, there are three screw holes 31 for the bolts 30, and the relative positional relationship of these three screw holes 31 is the same in FIGS. 3 and 4 (that is, viewed from the front). It's summery. That is, as mentioned above, the vertical positions of the base plate portion 5 and the like are reversed in the left and right exhaust manifolds 3, but only the connecting pipe 8 is connected to the base plate portion 5 without reversing its vertical position.
It is attached to the common specification connecting pipe 8.
Even if used for both exhaust manifolds 3, the positions of the bolt insertion holes 27 and 31 should match, and the bolts 3
0 makes it possible to fix the flange 25 to the cylinder outer surface 2.

In order to enable such a mounting structure, the bolt insertion holes 28 for fixing the flange 26 to the base plate part 5 and the corresponding screw holes in the base plate part 5 are arranged so that they are aligned with the center plane p of the connecting pipe 8. -p (plane extending in the longitudinal direction of the muffler including the connecting pipe center line P)
They are placed in a vertically symmetrical positional relationship with the two sides in between. More specifically, six bolt insertion holes 28 and corresponding screw holes in the base plate part 5 are provided at equal intervals around the connecting pipe center line P, and are symmetrical vertically and horizontally. There is.

[Effects of the invention] As explained above, according to the invention, the outer case parts 5 and 7 of the exhaust manifold 3 and the internal exhaust passage pipe 6 are formed as separate parts, and the outer case part is formed from the passage pipe 6. A strip-shaped base plate portion 5 to which is fixed
and a peripheral wall 7 that surrounds the installation space of the passage pipe 6 and is fixed to the base plate 5, so compared to the case where the entire exhaust manifold 3 is made of a cast product, the thickness and size and shape of each part can be reduced. There are fewer restrictions, manufacturing is simplified, and weight can be reduced by making each part thinner.

Furthermore, since the space 15 for the cooling water jacket can be reliably formed between the adjacent exhaust passage pipes 6, 6, it is possible to prevent the heat load from concentrating on a part of the passage pipe 6, and prevent cracks in the passage pipe 6. etc. can be eliminated.

Further, since the peripheral wall part 7 can be attached after the passage pipe 6 is fixed to the base plate part 5, the airtightness of the passage pipe 6 can be inspected by performing a water pressure test before installing the peripheral wall part 7. Therefore, even if an incompletely airtight portion is found in the passage pipe 6, it is easier to repair that portion than in the case where the entire passage pipe 6 is made of a cast product.

Furthermore, when taking measures to prevent overcooling, the heat insulation treatment can be performed on the heat insulation treatment portion 17 of the passage pipe 6 before attaching the peripheral wall portion 7, so that the treatment work is also simple.
In other words, if the entirety is a cast product, it would be virtually impossible to apply such heat insulation treatment to the internal passage pipe 6, but with the present invention, such treatment is possible. By appropriately controlling the cooling effect of water, overcooling of exhaust gas can be prevented.

[Brief explanation of drawings]

Fig. 1 is a schematic front view of an engine employing an embodiment of the present invention, Fig. 2 is a cross-sectional view of Fig. 1, and Figs. . 1... Cylinder assembly, 2... Cylinder outer surface,
3... Exhaust manifold, 5... Base plate section, 6...
... Exhaust passage pipe, 7 ... Peripheral wall section, 8 ... Connection pipe, 1
0...exhaust passage entrance part, 20...base plate part side edge.

Claims (1)

[Scope of utility model registration request] A plurality of exhaust outlets are arranged in series on an outer surface portion of a cylinder assembly having a plurality of cylinders, an elongated exhaust manifold is disposed along the installation area of the exhaust outlet, and the exhaust manifold is placed in a position facing the outer surface portion. a strip-shaped base plate extending along the installation area, an exhaust passage pipe located on the opposite side of the cylinder assembly across the base plate, a peripheral wall surrounding the installation space of the exhaust passage pipe, and the outer surface portion. and a plurality of connecting pipes arranged between the exhaust outlet and the base plate part to connect the exhaust outlet to the inlet of the passage pipe, the inlet end of the passage pipe is fixed to the base plate part, and Fix the edges to both longitudinal edges of the base plate,
An exhaust manifold for a multi-cylinder internal combustion engine, characterized in that a base plate is provided with a mounting seat for fixing a connecting pipe.