JPH0329537Y2 - - Google Patents

Description

[Detailed explanation of the invention] [Industrial application field] This invention collects the exhaust gas discharged from each cylinder of the engine into a static pressure chamber with a certain volume and removes the pulsating components of the exhaust gas. This invention relates to a static pressure type exhaust pipe that supplies an exhaust turbo supercharger.

[Prior Art] As a related technology that removes the pulsating components of the exhaust gas discharged from the cylinders of the engine and insulates the static pressure chamber in order to minimize the energy loss of the exhaust gas, the applicant has proposed There is the previously proposed "exhaust pipe structure" (Patent Application No. 162058/1982).

As shown in Fig. 4, this "exhaust pipe structure" covers the outer surface of an inner pipe b made of stainless steel that substantially partitions a static pressure chamber a with a heat insulating material c, and A bead portion d formed on the outer surface is configured to abut against the inner surface of an outer tube e made of cast iron, which surrounds the outer surface of the heat insulating material c.

[Problems to be solved by the invention] The above proposal aims at heat insulation in the static pressure chamber, and also by bringing the bead part that absorbs the thermal expansion of the inner tube into contact with the inner surface of the outer tube, to reduce the thermal expansion during thermal expansion. This is to prevent deformation of the inner tube.

However, as the exhaust gas temperature in the static pressure chamber gradually increases, the exhaust gas inlet or There is a problem in that the exhaust gas inlet or outlet formed by the inner shell is misaligned with respect to the exhaust port.

FIG. 5 shows a detailed cross-section of the main part of the inlet where the positional shift has occurred. As shown in the same figure, the inner shell member f that substantially forms the inlet A is connected to the outer shell g.
When a positional shift occurs with respect to the inner shell member f and the outer shell g, tensile stress is first concentrated at the joint h between the inner shell member f and the outer shell g. Then, since this stress is also applied to the connection portion between the other end of the inner shell member f and the inner shell i, stress is concentrated in this portion as well, resulting in an unfavorable state. Since thermal stress is repeatedly applied due to changes in the state of the internal combustion engine, the problem of gradual damage to the connection part h develops, and a solution is required.

[Means for Solving the Problems] This invention essentially consists of a steel inner shell that partitions a static pressure chamber and a thick cast iron outer shell that accommodates the inner shell through a heat insulating layer on the same plane. The thickness is divided into two parts, a flange joint part is formed on the inner shell along the dividing surface, and the flange joint part of the inner shell is fit into the outer shell along the dividing surface in a spigot manner and compressed by bolt fastening. A solid flange joint is formed, and an expandable flexible pipe is provided by penetrating the heat insulating layer and extending between the exhaust gas flow ports of the inner shell and the outer shell.

[Function] When a steel plate inner shell is housed within a thick cast iron outer shell, the flange joints of the inner and outer shells are butted together, and the flange joints of the outer shell are bolted together.
The flange joint portion of the inner shell is fitted into the flange joint portion of the outer shell in a spigot manner and is pressed. Therefore, even if pulsations or large pressure fluctuations occur within the inner shell during exhaust braking, the seal at the connection remains constant and the position of the inner shell relative to the outer shell remains constant. Pressure exceeding the capacity of the flange joint
When added to the inner shell or when the inner shell undergoes thermal expansion, the flexible tube freely expands and contracts at this time, moving the inner shell relative to the outer shell. Therefore, the seal of the inner shell is not compromised even at this time. Incidentally, the heat insulating layer supports the inner shell, cuts off heat conduction to the outer shell, suppresses thermal expansion of the outer shell, and reduces energy loss of exhaust gas.

[Embodiment] A preferred embodiment of this invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the exhaust pipe body 1 consists of a box-shaped inner shell 2 made of heat-resistant metal such as stainless steel, a heat insulating layer 3 covering the outer surface (surface) of the inner shell 2, and the heat insulating layer 3. It is mainly composed of a cast iron outer shell surrounding the outer surface of a covered inner shell 2. That is, the exhaust pipe main body 1 has a three-layer structure.

The inner shell 2 is divided into two parts, an inner shell 2a on the internal combustion engine side 4 and an inner shell 2b on the exhaust turbocharger side 6, in a direction crossing the direction of installation on the internal combustion engine side 4. , 2b are integrally molded with flange joint portions 2c, 2d for butt-joining the inner shells 2a, 2b, respectively. These flange joints 2c and 2d are formed by bending the portions along the dividing plane outward. In the inner shell 2a (hereinafter referred to as the first inner shell) on the internal combustion engine side 4, exhaust gas inlets 5 are opened at intervals in the longitudinal direction on a mounting surface 2e serving as the bottom of the box. On the other hand, the inner shell 2b (hereinafter referred to as the second inner shell) on the exhaust turbo supercharger side 6 has a mounting surface 2f that serves as the bottom of the box and the other side with respect to the mounting surface 2e. The discharge port 7 is open.

Therefore, when the flange joint parts 2c and 2d of the first inner shell 2a and the second inner shell 2b are butted and joined together, exhaust gas flows in the first and second inner shells 2a and 2b, causing pulsation. A static pressure chamber 8 is defined in which components are removed and discharged.

In addition, in the butt-joined state, the first and second
The inner shells 2a, 2b have bottomed cylindrical constricted portions 9, 10 that extend in the relative direction and join to the inner surfaces of the opposing inner shells 2e, 2f with the inlet 5 interposed therebetween.
are formed respectively. These aperture parts 9, 1
0 is formed to be smooth and perpendicular to the mounting direction so that the respective bottoms 9a and 10a are hermetically joined to each other.

Incidentally, an inflow pipe 11 and a discharge pipe 12 are connected to the inflow port 5 and the discharge port 7, respectively.

The inlet tube 11 has a flange 12 at its lower end and is formed with at least one corrugated flexure 13 spaced apart in the axial direction of the tube. After the inflow pipe 11 is inserted from inside the first inner shell 2a, the flange 12 is fixed to the inner surface of the mounting surface 2e of the first inner shell 2a, and the inflow pipe 11 is integrated into the first inner shell 2a.

On the other hand, the discharge pipe 12 has a lower end fitted into and fixed to a cylindrical portion 14 formed along the opening edge of the discharge port 7, and a flange 15 hermetically joined to the inner surface of the outer shell, which will be described later, at the upper end. and further includes at least one flexible portion 1 spaced apart in the axial direction of the tube.
6 and is molded. Here, the flexible portions 13 and 16 of the inflow pipe 11 and the discharge pipe 12 are formed along the circumferential direction and have a corrugated cross section.

The outer surfaces of the first and second inner shells 2a and 2b in the joined state are covered with a heat insulating layer 3 of an appropriate thickness,
Inner peripheral surfaces 9b and 10b of the throttle parts 9 and 10, outer peripheral surface 11a of the inflow pipe 11, and outer peripheral surface 1 of the discharge pipe 12
2a is also covered with a heat insulating layer 3 of suitable thickness. This results in a heat-insulated inner shell 2.

Now, the outer shell 20 is formed so as to cover the entire outer surface of the heat insulating layer 3, and the outer shell 20a (hereinafter referred to as the first outer shell) on the internal combustion engine side 4 at the dividing surface c of the inner shell 2. and the outer shell 20 of the exhaust turbo supercharger side 6
b (hereinafter referred to as the second outer shell). These divided first and second outer shells 20a, 20b
are provided with flange joints 20c, 20d into which the flange joints 2c, 2d, in which the first and second inner shells 2a, 2b are connected to each other at the dividing plane c, are fitted with a spigot and are sandwiched therebetween. Molded in one piece. The part that fits and is inserted into the spigot is the second part.
As shown in the figure, even if the outer edges E of the flange joints 2c and 2d of the first and second inner shells 2a and 2b are formed to completely engage, the outer edges E and the outer edges E as shown in FIG. Relief part D during pressure fluctuations and thermal expansion
may be formed.

On the other hand, the opposing inner surfaces of the first and second outer shells 20a and 20b engage with the inner circumferential surfaces 3a of the heat insulating layers of the constricted portions 9 and 10, respectively, and are seated on the bottoms 9a and 10a. , 10a are integrally provided, and a second outer shell 20b is disposed on the axes of these distance members 21a, 21b and the bottoms 9a, 10a. Bolt guide holes 23a, 23b, and 23c are opened to guide the mounting bolts 22 that are inserted from the side and pass through the first outer shell 20a.

Furthermore, these divided first and second outer shells 2
In the embodiment, the flange joints 20c and 20d on the internal combustion engine side 4 are provided at the flange joints 20c and 20d on the internal combustion engine side 4 to connect the first and second outer shells 20a and 20b at intervals on the circumferential surface, respectively. Joint part 20c
A female thread 28 is provided in the exhaust turbo supercharger side 6, and a bolt hole 29 is provided in the flange joint portion 20d on the exhaust turbo supercharger side 6. 30 is a connecting bolt.

Therefore, when the connecting bolt 30 is screwed into the female thread 28, the exhaust pipe main body 1 having an integrated three-layer structure is formed.
is obtained. 31 is a packing ring, which is attached to the flange 15 of the exhaust pipe 12 by a bolt on the turbine side flange of the exhaust turbo supercharger (not shown).
is provided to be sandwiched between the packing ring 31 and the second outer shell 20b. 32 is a port flange to which the upper end of the inflow pipe 11 is fixed. Therefore, the port flange 32 is provided for airtightly connecting the inlet pipe 11 to the internal combustion engine side.

In addition, the first and second outer shells 20a,
20b is formed by cast iron casting, the first and second inner shells 2a, 2b, the inflow pipe 11, and the discharge pipe 12 are made of heat-resistant and corrosion-resistant metal steel plates such as stainless steel, and the heat insulating layer 3 is made of A
Composed of ceramic laminated fibers such as ₂ O ₃ .

Next, the action will be explained.

Exhaust gas enters the static pressure chamber 8 from the inlet 5 and from which pulsating components are removed is supplied to the exhaust turbo supercharger (not shown) from the exhaust port 7 without losing energy through the heat insulating layer 3. .

The inner shells 2a, 2b are supported by the flange joints 2c, 2d and the distance members 21a, 21b against the outer shell, so they are prevented from deforming even during pressure fluctuations. 2a,
When thermal expansion occurs in the inner shells 2a, 2b, the flexible portions 13, 16 of the inlet pipe 11 and the outlet pipe 12 bend and allow relative movement with respect to the outer shells 20a, 20b. To maintain a constant state of connection without putting stress on a connection part with a discharge pipe 12.

Therefore, it is possible to obtain a highly reliable hydrostatic exhaust pipe whose gas sealing properties are not impaired under any conditions.

In the embodiment, by tightening the connection bolt 30, the flange joints 2c, 2d of the inner shells 2a, 2b are tightened.
The flange joints 20c of the outer shells 20a, 20b,
20d was explained as being fitted with a spigot and being inserted, but the flange joints 2c, 2 of the inner shells 2a, 2b
d extends outward and the extended flange joint part 2
Of course, it is also possible to fasten c and 2d together with the connecting bolt 30.

[Effects of the invention] As is clear from the above explanation, this invention facilitates the assembly and maintenance of the inner shell and the heat insulating layer, and also reduces pressure fluctuations and thermal expansion of the joined exhaust pipe body. However, sufficient gas sealing properties and high rigidity can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway front view showing a preferred embodiment of this invention, Figs. 2 and 3 are detailed cross-sectional views of main parts of Fig. 1, and Figs. 4 and 5 show a conventional exhaust pipe structure. FIG. In the figure, 1 is the exhaust pipe body, 2 is the inner shell, 2c and 2
d is a flange joint of the inner shell, 5 is an inlet as a flow port, 7 is an outlet as a flow port, 11 is an inflow pipe as a flexible pipe, 12 is a discharge pipe as a flexible pipe, 13 and 16 are flexible pipes. part, 20 is the outer shell, 2
0c and 20d are flange joints of the outer shell.

Claims (1)

[Claims for Utility Model Registration] (1) A steel plate inner shell that substantially partitions a static pressure chamber and a cast iron thick outer shell that houses the inner shell through a heat insulating layer are divided into two on the same plane. Then, a flange joint part of the inner shell is formed along the dividing surface of the inner shell, and a flange joint part of the inner shell is fitted to the outer shell along the dividing surface in a spigot manner and clamped by bolting. 1. A static pressure exhaust pipe characterized in that a flange joint is formed, and a stretchable flexible pipe is provided by passing through the heat insulating layer and extending between the exhaust gas flow ports of the inner shell and the outer shell. (2) The hydrostatic exhaust pipe according to claim 1, wherein the flow port is an inlet for exhaust gas. (3) The hydrostatic exhaust pipe according to claim 1, wherein the flow port is an exhaust gas discharge port.