JP2564304B2 - Static pressure type exhaust pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention collects exhaust gas discharged from each cylinder of an engine in a static pressure chamber having a constant volume to remove the pulsating component of the exhaust gas. The present invention relates to a static pressure type exhaust pipe supplied to an exhaust turbocharger.

[Prior Art] As a related technique in which the pulsating component of exhaust gas discharged from an engine cylinder is removed and the static pressure chamber is insulated in order to suppress energy loss of the exhaust gas as much as possible, the present applicant first Proposed "Exhaust pipe structure" (Japanese Patent Application No. 61)
-162058).

As shown in FIG. 10, this "exhaust pipe structure" substantially covers the outer surface of a stainless metal inner tube b that defines the static pressure chamber a with a heat insulating material c, and The bead portion d formed on the outer surface is configured to be in contact with the inner surface of the outer pipe e made of cast iron that surrounds the outer surface of the heat insulating material c.

[Problems to be Solved by the Invention] The above-mentioned proposal aims at heat insulation in a static pressure chamber, and by bringing a bead portion absorbing thermal expansion of the inner pipe into contact with the inner surface of the outer pipe, the inner pipe at the time of thermal expansion It tries to prevent the deformation of.

However, when considering the mass productivity and maintenance inspection of the above proposal, the following problems remain.

It is difficult to determine whether or not the state of the inner pipe and the heat insulating material is appropriate after casting by casting the inner pipe covered with the heat insulating material as a core and forming the outer tube as the outer shell by casting.

Since the volume of the inner pipe increases as the number of cylinders of the internal combustion engine increases, the area of the outer pipe in which the casting is formed becomes large and the mold becomes complicated. (Partitions, locations and number of gates, risers, etc.) When the volume of the inner pipe becomes large, the total weight after casting exceeds the carrying capacity of one operator, and each processing step (machining)
It becomes difficult to carry and install.

After casting, it is not possible to perform maintenance, inspection, replacement and reinforcement of the heat insulating material and inner pipe.

An object of the present invention is to provide a static pressure type exhaust pipe having a structure capable of being disassembled, assembled and inspected.

[Means for Solving the Problems] [In the present invention, a heat insulating layer is formed on the outer surface of an inner shell having an exhaust gas inlet and an exhaust port and defining a static pressure chamber, and the heat insulating layer is provided outside the heat insulating layer. At least two parts are butt-connected and connected to each other to form an outer shell for supporting the inner shell, and a tightening bolt for penetrating the inner shell and the outer shell to be attached to the cylinder head is surrounded, and an axial force of the tightening bolt. A distance member for ensuring the above is provided, a heat insulating material and an annular member joined to the inner shell are provided on the outer circumference of the distance member, and a dividing portion is provided for appropriately dividing the distance member according to the division of the outer shell. [Operation] The inner shell covered with the heat insulation layer is housed in at least two or more divided outer shells, and the outer shells are integrally joined. Also allows to split. This allows the inner shell and the outer shell to be formed into a predetermined shape in each processing step in each processing step, and can be replaced and maintained and inspected by dividing even after the outer shell is joined.

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

As shown in FIG. 1, a static pressure type exhaust pipe 1 includes a box-shaped inner shell 2 made of a heat-resistant metal such as stainless steel, and a laminated ceramic fiber such as Al ₂ O ₃ covering the outer surface (surface) of the inner shell 2. It is mainly composed of a heat insulating material 3 made of and a cast iron outer shell surrounding the outer surface of the inner shell 2 covered with the heat insulating material 3. That is, the static pressure type exhaust pipe 1 having a three-layer structure is constructed. The inner shell 2 has an inflow port 4 formed on one side surface 5 thereof and having a space in the longitudinal direction and connecting the inner shell 2 and an exhaust port (not shown) of the internal combustion engine. That is, the one side surface 5 forms the mounting surface side with respect to the internal combustion engine. The inner shell 2 centered around these inlets 4 has one side surface 5
And an annular member 7 penetrating the other side surface 6,
Both ends of each of the annular members 7 are joined by welding or the like while keeping airtightness on both side surfaces 5 and 6. Further, between the annular members 7 near the inflow port 4, a female plug 9 having an internal thread 8 on the inner surface is integrally fixed to the inflow port 4 side. On the other hand, the other side surface 6 is provided with an exhaust port 10 for exhausting the exhaust gas, which has been supplied into the inner shell 2 to remove the pulsating component, to a downstream exhaust turbocharger (not shown) side. A connection pipe 11 made of the same material as the inner shell 2 is attached to the outlet 10.

The outer surface of the inner shell 2 and the connecting pipe 11 thus formed is covered with a heat insulating material 3 having a predetermined thickness, and the inner surface 7a of the annular member 7 is also an annular heat insulating material 12 having a predetermined thickness. Is covered with. That is, each heat insulating material 3, 12 forms a heat insulating layer.

By the way, the inner shell 2 in the embodiment is configured by connecting pieces of the inner shell 2 which are previously divided and molded into a predetermined shape, but pressure fluctuations due to exhaust gas (exhaust pulsation, pressure fluctuations during exhaust braking, etc.). In order to sufficiently counter the above, a connecting portion X that overlaps with each other in the direction of large pressure fluctuation is provided to obtain high rigidity. From this viewpoint, the connecting portion X of the annular member 7 and the connecting portion X of the connecting pipe 11 are also bent and formed in an annular shape.

On the other hand, a connection ring 14 whose outer surface is covered with the heat insulating material 3 is fitted and fixed to the exhaust manifold side 13 of the connection pipe 11, and the end surface of the connection ring 14 is formed by folding back the connection side end surface. The flange 15 is fixed so as to be in close contact with the surface of the flange 15, and the fixed flange 15 has a guide hole (not shown), and the connecting ring 14 has a female screw 16 for fixing on the axis of the guide hole. It is formed.

The inner shell 2 thus formed is covered with the outer shell 20 made of cast iron to form one static pressure type exhaust pipe 1.

As shown in FIGS. 1 to 5, the outer shell 20 is 2 in a plane orthogonal to the axial direction of the annular member 7 in this embodiment.
It is divided into two parts and cast, and comprises an outer shell 22 on the internal combustion engine side and an outer shell 23 on the exhaust manifold side. As shown in FIGS. 3 to 4, each of the divided outer shells 22 and 23 is
Mounting bosses 25 and 26 for connecting the outer shells 22 and 23 to each other are provided at intervals on the peripheral surface 24. In the embodiment, the mounting boss 25 on the internal combustion engine side 27 is provided with a female screw 28, and the mounting boss 26 on the exhaust manifold side 13 is provided with a bolt hole 29. “Furthermore, as shown in FIG. 5, a distance member 30 is erected on each of the inner surfaces 22a, 23a of the outer shells 22, 23 divided into these. Fits on the inner surface 12a of the heat insulating material 12.
Therefore, the heat insulating material 12 and the inner shell 2 are provided on the outer periphery of the distance member 30.
Is provided, and when the outer shells 22 and 23 are connected,
The distal ends of the distance member 30 are arranged to face each other. A space S is provided as a tightening margin between the facing tip surfaces.
Are formed. That is, depending on the tip surface and the spacing S,
A dividing portion is configured to divide the distance member 30 according to the division of the outer shells 22 and 23. As shown in FIG. 1, the distance member 30 has a bolt insertion hole 31 on its axis which penetrates the outer shells 22 and 23, and a tightening bolt 32 inserted from the exhaust manifold side 13 is inserted into the cylinder. When tightened to the head side, the above-mentioned interval S shrinks to "0".
That is, the distance member 30 surrounds the tightening bolt 32 to be attached to the cylinder head, and ensures the axial force of the tightening bolt 32 by abutting the end faces thereof. Reference numeral 33 is a dish-shaped cross plug having an inflow passage 34 on the shaft center, and is fitted to the female plug 9 described above.
Exhaust gas is sealed by the tapered surface 45.

By the way, the outer shell 23 of the exhaust manifold side 13 is
A ring portion 35 that sits airtightly on the flange 15 of 11 is formed, and a guide hole 36 that guides the connection bolt of the exhaust manifold and fits into the internal thread 16 of the connection ring 14 is formed in the ring portion 35.

Therefore, the inner shell 2 shown in FIG. 2 (a) is covered with the heat insulating material 3 as shown in FIG. 2 (b), and the divided outer shells 22 and 23 are covered with bolts 37 as shown in FIG. 2 (c). When connected by, one static pressure type exhaust pipe 1 is constructed. The exhaust gas supplied from the inflow passage 34 and the inflow port 4 of the static pressure type exhaust pipe 1 into the inner shell 2, that is, the static pressure chamber 50 loses the pulsating component of the gas and passes through the downstream exhaust manifold. It is sent to the exhaust turbocharger.

At this time, since the inner shell 2, the distance member 30 and the connecting pipe 11 are covered with the heat insulating materials 3 and 12, respectively,
Heat is prevented from moving from the shell to the outer shell 20, and the energy loss of the exhaust gas is minimized. Also, by covering the outer circumference of the distance member 30 with the heat insulating material 12, the distance member 30
The thermal expansion of the tightening bolt can be suppressed.
It is possible to maintain a constant connection with the internal combustion engine without causing plastic deformation of 32 due to thermal expansion. That is, the gas sealability is greatly improved, and the degree of freedom in designing the attachment of the static pressure type exhaust pipe 1 can be increased. This is because when the volume of the static pressure chamber 50 is secured, the static pressure type exhaust pipe 1 becomes large, and when mounting on the internal combustion engine (cylinder head), it is necessary to consider the relationship with other auxiliary machines and engine room. However, by adopting a structure in which the tightening bolt 32 surrounded by the distance member 30 penetrates through the static pressure chamber 50, the position of the tightening bolt 32 is not restricted, and the static pressure exhaust pipe 1 can be placed in any posture. But you can install it.

 Hereinafter, another embodiment will be described.

As shown in FIG. 6, in this embodiment, the standing length of the distance member 30 formed in each of the outer shells 22 and 23 of the static pressure type exhaust pipe 1 described in the above embodiment is shortened, and the distances facing each other are shortened. An example in which an intermediate distance member 30a as an intermediate member is provided between the members 30 is shown. That is, the intermediate distance member 30a constitutes a dividing portion. According to this configuration, when the facing surface of the distance member 30 is machined (milling or shaper processing) to improve the flatness of the end surface, chattering during processing can be eliminated and the accuracy can be improved. Further, in this embodiment, the heat insulating material 3
The heat insulating layer formed by can be divided into two in the dividing direction of the outer shells 22,23.

Next, an embodiment in which the divided outer shells 22 and 23 can be connected by the distance member 30b will be described.

As shown in FIG. 7, reference numerals 22 and 23 are the outer shells described in the above embodiment. Female screws 46 are formed in the outer shell 22 of the internal combustion engine side 27 at the portions sandwiching the inflow port 4, and the distance member 30b is integrally fitted to the female screws 46. On the inner surface of the other end of the distance member 30b, for example, an engaging portion 3 for a hexagon wrench
8 is formed. On the other hand, the outer shell 23 of the exhaust manifold side 13
A plug 40 having an insertion hole 39 in the shaft core is fitted therein, and gas sealing is performed by this plug 40 and the surface pressure of the end face of the distance member 30b. That is, these female screw 46 and plug
The dividing portion is constituted by 40. 48 is a seal plate. When the plug 40 is not provided, as shown in FIG. 8, female threads 46 may be formed on each of the outer shells 2223 and male threads 41 may be formed on both ends of the distance member 30b.

In the description of these embodiments, the outer shells 22 and 23 have been described as being orthogonal to the distance member 30. However, as shown in FIGS. 2 (d) and 9, the parallel direction may be a dividing surface.
As the distance member in this case, the distance members 30b and 30c described in FIGS. 7 and 8 are used.

EFFECTS OF THE INVENTION As is apparent from the above description, according to the present invention, the inner shell having the heat insulating layer formed on the surface can be divided into at least two or more pieces and can be supported by the outer shell.
Maintenance / inspection and replacement of the inner shell and heat insulation layer are possible, and transportation as parts and processing as parts are easy and cost reduction and quality improvement can be achieved. Also, by providing a heat-insulating distance member that surrounds the tightening bolts, the degree of freedom in designing the attachment to the cylinder head is increased, and plastic deformation due to thermal expansion of the tightening bolts is prevented to improve gas sealing performance. Is achieved.

[Brief description of drawings]

1 is a partially cutaway front view showing a preferred embodiment of the present invention, FIG. 2 is a schematic view showing an assembling procedure, FIG. 3 is a front view showing a mounting boss, and FIG. 4 is an arrow IV in FIG. Fig. 5, Fig. 5 is a view taken along the line V-V in Fig. 3, Fig. 6 is a partial sectional front view showing another embodiment, and Figs. 7 and 8 are other embodiments of the distance member. FIG. 9 is a detailed cross-sectional view of a main part, FIG. 9 is a top view showing another example of division, and FIG. 10 is a partial cross-sectional front view showing an exhaust pipe structure as a conventional example. In the figure, 1 is a static pressure type exhaust pipe, 2 is an inner shell, 3 is a heat insulating material, 4 is an inlet, 7 is an annular member, 10 is an outlet, 20 is an outer shell, and 32 is a tightening bolt.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tokuro Kobayashi 1150 Shimoimaizumi, Ebina City, Sanwa Metal Industry Co., Ltd. (56) Reference JP-A-60-145422 (JP, A) JP, U) Actually developed 50-149718 (JP, U)

Claims (1)

(57) [Claims] 1. A heat insulating layer is formed on an outer surface of an inner shell having an exhaust gas inflow port and an exhaust gas exhaust port and defining a static pressure chamber, and the heat insulating layer is divided into at least two parts and butt-connected to each other. An outer shell that supports the inner shell is formed, and a distance member that penetrates the inner shell and the outer shell and surrounds a tightening bolt for attaching to the cylinder head and that secures an axial force of the tightening bolt is provided. A hydrostatic type, characterized in that a heat insulating material and an annular member joined to the inner shell are provided on the outer periphery of the distance member, and a dividing portion is provided for appropriately dividing the distance member according to the division of the outer shell. Exhaust pipe. "