JPH0442491Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an exhaust system structure for a V-type engine in which a pair of exhaust manifolds attached to both left and right banks are connected by a connecting pipe, and in particular, the invention relates to an exhaust system structure for a V-type engine in which a pair of exhaust manifolds attached to both left and right banks are connected by a connecting pipe. This invention relates to improvements in the mounting structure of.

(Prior art) Conventionally, as an exhaust system structure for a V-type engine,
As shown in Japanese Utility Model Application Publication No. 59-148415, a pair of exhaust manifolds fixed to each cylinder head of the left and right banks are connected between both banks on the rear side of the engine by an expandable connecting pipe having a bellows part. Accordingly, a structure is known in which both exhaust manifolds are communicated and brought together. In such a structure, in order to prevent exhaust heat from being dissipated into the passenger compartment from the part where both banks are connected via the connecting pipe, a heat insulating insulator is installed outside this part. There is. However,
The insulator is usually made of a hard plate material such as a steel plate, and both ends of the insulator are attached to the connecting pipes or the ends of the exhaust manifold on both sides of the bellows, so the insulator prevents the bellows from expanding and contracting. At the same time, the thermal stress of the exhaust manifold and the connecting pipe acts on the insulator, and in order to prevent damage to the insulator and its attachment parts, high strength materials are required.

In addition, in the device disclosed in the above-mentioned publication, when the bellows part of the connecting pipe does not have sufficient elasticity, a reinforcing plate that also serves as an insulator actively suppresses the expansion and contraction of the connecting pipe. We are trying to prevent thermal expansion of that material. However, it is possible to provide sufficient elasticity to the bellows part in manufacturing, and the connecting pipe can be adjusted in response to thermal expansion of the exhaust manifold located outside the attachment parts at both ends of the reinforcing plate. Expanding and contracting is necessary to absorb thermal stress. Therefore, if the expansion and contraction of the connecting pipe is suppressed by the reinforcing plate, it becomes impossible to absorb the thermal stress of the exhaust manifold, and as mentioned above, a large load is placed on the insulator (reinforcing plate). Become.

(Purpose of the invention) In view of the above-mentioned circumstances, this invention is designed to absorb thermal expansion of the exhaust manifold when an insulator is installed outside the part where a pair of exhaust manifolds of a V-type engine are connected by an expandable connecting pipe. In addition to being able to perform the functions well,
An object of the present invention is to provide an exhaust system structure for a V-type engine that can prevent large stress from acting on an insulator and its mounting portion.

(Structure of the invention) The present invention installs exhaust manifolds on the outside of each of the left and right banks of a V-type engine, and connects the exhaust manifolds between the two banks.
In the exhaust system structure of a V-type engine connected by an expandable connecting pipe having a bellows part, insulators are attached to the exhaust pipe parts on both sides of the connecting pipe on both sides of the bellows part, and both insulators are overlapped at one end of each. and connect both insulators at this overlapping part by a coupling means,
Further, by forming a cutout portion of at least one of the insulators through which the coupling means is inserted to be long in the axial direction of the connecting pipe, both insulators can be slid relative to each other.

With this configuration, when the exhaust manifold thermally expands, the bellows section of the connecting pipe expands and contracts accordingly, causing both of the insulators to slide against each other, allowing the bellows section to expand and contract, thereby maintaining the thermal expansion absorption function. That will happen.

(Embodiment) FIGS. 1 and 2 show the overall structure of a V-type engine and its exhaust system, and this engine is mounted, for example, in an engine room at the front of a vehicle (not shown). As shown in these figures, the cylinder block 1 of the engine is formed in a V shape, and the left and right banks 2 and 3 are provided with cylinder heads 4 and 5, respectively, and furthermore, cylinder head covers 6 and 7 are attached. There is. An intake manifold 8 connected to both cylinder heads 4 and 5 is arranged between the banks 2 and 3. Also, both banks 2 and 3
Exhaust manifolds 9 and 10 are installed on the outside of the
is installed. Each exhaust manifold 9,
10, each branch part 9a, 10a is connected to each cylinder head 4, 5, and the gathering part 9b, 10b extends toward the rear side of the engine, and is further bent to extend in a direction between both banks 2, 3. It is provided with extending portions 9c and 10c. One exhaust manifold 9 is provided with a connecting portion 9d to the downstream exhaust pipe 11.

Extending portion 9 of both exhaust manifolds 9 and 10 above
c and 10c are connected by a connecting pipe 12, and this connecting pipe 12 and the above-mentioned extension portions 9c and 10c constitute an exhaust pipe portion that connects and brings together both exhaust manifolds 9 and 10. The connecting pipe 12 has a bellows part 13 at its center, so that it can expand and contract, and both ends of the connecting pipe 12 have respective flange parts at the ends of the respective extension parts 9c and 10c. They are connected by bolts, etc. A protective member 14 made of woven fibers is attached around the bellows portion 13 to prevent the bellows portion 13 from being damaged by stones or the like.

Further, a pair of insulators 15 and 16 for heat insulation made of steel plates or the like are arranged outside the range extending between the connecting pipe 12 and the extending portions 9c and 10c of the exhaust manifolds 9 and 10 on both sides thereof. ing. In the figure, insulators 1 are also installed outside the exhaust manifolds 9 and 10 on both the left and right sides.
7 and 18 are deployed.

3 and 4 show the specific structure of the exhaust manifold connecting portion and a pair of insulators 15 and 16 disposed in this portion. As shown in these figures, the pair of insulators 15 and 16
is the connecting pipe 12 and the extending portions 9 on both sides thereof.
c, 10c, and is formed to cover approximately half the circumference from the top to the rear. Attachment portions 19 and 20 are attached to the exhaust pipe portions on both sides of the bellows portion 13, that is, to the connecting pipes 12 on both sides of the bellows portion 13, or to the respective extension portions 9c and 10c on both sides thereof.
are provided protrudingly, and the insulators 15, 16 are attached to these attachment portions 19, 20 with bolts 21, 22, etc.

One end of each of the above-mentioned insulators 15 and 16 is overlapped inwardly and outwardly, and at this overlapping portion, both insulators 1
5 and 16 are connected by a coupling means such as a bolt,
In addition, a cutout for insertion of the coupling means in at least one of the insulators is formed to be long in the tube axis direction of the connecting pipe 12, and by such a coupling means and a cutout for insertion of the coupling means long in the tube axis direction, both insulators can be inserted. A connecting means 23 is configured to slidably connect 15 and 16 to each other. In this embodiment, both insulators 15,1
6 are connected by a coupling means consisting of a bolt 24 and a nut 25, and one insulator 1
By making the bolt insertion hole 26, which serves as the cut-out portion for inserting the coupling means of No. 6, into the elongated hole 26, the elongated hole 2
Both insulators 15 and 16 are slidable within the formation range of 6. The overlapping portion and the connecting means 23 are arranged at the center of the connecting pipe 12, that is, outside the portion where the bellows portion 13 is covered with the protective member 14. Further, a spring washer 27 is interposed between the bolt 24 of the connecting means 23 and one of the insulators 15, so that both the insulators 15 and 16 can slide smoothly without rattling. There is.

In the exhaust system structure configured in this way,
The exhaust heat dissipated from the connecting pipe 12 and the exhaust manifolds 9, 10 on both sides thereof is blocked by the pair of insulators 15, 16, and is prevented from being transmitted to the vehicle interior or the like. Further, when both exhaust manifolds 9 and 10 thermally expand, the bellows portion 13 of the connecting pipe 12 expands and contracts in response to this, but at this time, the pair of insulators 15 and 16 are connected at the overlapping portion by a slidable connecting means 23 in which a bolt 24 is inserted into an elongated hole 26, so that the bellows parts 13 slide with each other as the bellows part 13 expands and contracts.

Therefore, the expansion and contraction of the bellows portion 13 in accordance with the thermal expansion of the exhaust manifolds 9 and 10 causes the insulator 1 to expand and contract.
5 and 16, the thermal expansion absorption effect of the bellows portion 13 is effectively exhibited, and large stress is prevented from acting on the insulators 15 and 16 themselves.

Further, as in the above embodiment, if the protective member 14 is provided around the bellows part 13 at the center of the connecting pipe 12, the insulators 15 and 16 are overlapped on the outside thereof, and the slidable connecting means 23 is provided here. Since the exhaust heat radiated from the bellows portion 13 is blocked to some extent by the protective member 14, this is advantageous in preventing thermal deterioration of the bolts 24, nuts 25, etc. of the connecting means 23.

(Effect of the invention) As described above, according to the exhaust system structure of the V-type engine of the present invention, the insulator, which is attached to the part where both exhaust manifolds of the V-type engine are connected by the expandable connecting pipe, can slide in the overlapping part. Since it consists of a pair of insulators connected to the bellows, the expansion and contraction of the bellows part is not hindered and thermal expansion of the exhaust manifold can be effectively absorbed. This provides the advantage that the insulator and its mounting portion will not be damaged even if a strong material is not used.

[Brief explanation of the drawing]

Fig. 1 is an overall front view of a V-type engine showing an embodiment of the present invention, Fig. 2 is a plan view of the same, Fig. 3 is an enlarged sectional view of the main parts, and Fig. 4 is an enlarged plan view of the same. . 1...Cylinder block, 2,3...Bank,
4, 5... Cylinder head, 9, 10... Exhaust manifold, 12... Connecting pipe, 13... Bellows portion, 15, 16... Pair of insulators, 23
...Slideable connection means.

Claims (1)

[Scope of utility model registration request] In the exhaust system structure of a V-type engine, an exhaust manifold is attached to each outer side of the left and right banks of the V-type engine, and the exhaust manifold is connected between the two banks by an expandable connecting pipe having a bellows part. Insulators are attached to the exhaust pipe portions on both sides of the connecting pipe across the bellows portion, the two insulators are overlapped at one end of each, and the two insulators are connected by a connecting means at the overlapped portion, and at least one of the insulators is An exhaust system structure for a V-type engine, characterized in that both insulators can be slid relative to each other by forming a cutout portion for insertion of a coupling means to be long in the axial direction of the connecting pipe.