JPH048816A - Exhaust manifold - Google Patents

Abstract

PURPOSE:To provide a lightweight exhaust manifold having a high rigidity and to enhance the emission characteristic during engine operation at a low temperature by providing a flange formed therein with pipe connecting holes communicated with exhaust ports in cylinder heads, and by forming a hollow part in the peripheral section of the joint part of each of pipes fixed respectively in the pipe attaching holes. CONSTITUTION:An exhaust manifold 3 is secured to a cylinder head 7 through the intermediary of a gasket 7 by making a bolt piercing through an inflow side flange 4. Then, a pipe 5 is led through each of pipe attaching holes 8C in an upper flange 8, and is welded at its front end to a part around a pipe attaching hole 9C in a strip plate 9 of a lower flange 9 along its entire periphery W1. In this arrangement, a hollow part H is formed in the peripheral part of the inflow side flange 4, which is joined to the pipe 5. Further, the hollow part H serves as one kind of a heat shielding material so as to restrain heat from being dissipated from a cylinder heat 1. Further, the weight of the inflow side flange 4 is reduced while its rigidity is enhanced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an improvement in an exhaust manifold attached to a cylinder head of an automobile engine.

[Prior Art] Recently, as an exhaust manifold for collecting exhaust gas from an engine, a structure in which a flange and a pipe are welded together as shown in Japanese Utility Model Application No. 1-143679, for example, is used to collect exhaust gas from an engine. It has been adopted as one of the countermeasures.

As such a welded exhaust manifold, for example, an exhaust manifold as shown in FIG. 10 is known.

In the figure, 101 is an exhaust manifold, which has an inflow side flange 102 and four pipes 103. The inflow side flange 102 is made of a metal strip material, is solid, has a thick plate, and has a large number of bolt through holes 1.
02A is drilled. The exhaust manifold 101 is fixed to the cylinder head by passing a bolt (not shown) through the through hole 102A and screwing it to the cylinder head (not shown).

Then, the pipe attachment hole 10 of this inflow side flange 102
Four pipes 103 are inserted into each of the pipes 2B and fixed by welding, and the pipe attachment holes 102B communicate with each exhaust port (not shown) of the cylinder head.

[Problem to be solved by the invention]

However, in the conventional exhaust manifold 101,
In cold weather, when the engine is started and the engine is heated, the heat of the engine is immediately transferred from the cylinder head to the inflow side flange 102. Inflow side flange 102
is made of metal strip material, is solid, and has a thick plate.
A large amount of heat is conducted to the pipe 102, and a large amount of heat is also transferred from the heated pipe 103 to the inflow side flange 102. That is, the inflow side flange 102 has a function like a kind of heat transfer material for the engine. Therefore, when the engine is started in cold weather, a large amount of heat escapes from the cylinder head, making it impossible to warm up the engine quickly, resulting in poor engine emission performance at low temperatures.

Further, the inflow side flange 102 is made of a metal strip material, is solid, and has a thick plate, so there is a problem that although the rigidity is high, the weight is large.

Therefore, for example, an exhaust manifold 12'l having a welded structure as shown in FIG. 11 has been devised and known.

The inflow side flange 122 of this exhaust manifold 121 includes a plate material 122A and a bent portion 12 formed on the peripheral edge thereof.
2B, and a plurality of pipe attachment holes 122C are formed. The pipe 123 is passed through this pipe attachment hole 122C and fixed to the inflow side flange 122 by welding.

In the exhaust manifold 121 having such a structure, the weight of the inflow side flange 122 can be reduced;
Its rigidity is low, and as a result, as the pipe 123 deforms due to thermal expansion and contraction, a force is generated on the inflow side flange 122 that is in contact with the cylinder head 124 to cause its end to be rolled up from the cylinder head 124. When this happens, the inflow side flange 122, which has low rigidity, is easily deformed, and there is a problem that the end of the inflow side flange 122 may curl up, causing a gas leak.

The present invention was made in order to solve the above-mentioned problems, and its purpose is to provide an exhaust manifold that can increase rigidity, reduce weight, and improve emission performance at low temperatures of the engine. It is to provide.

[Means for Solving the Problem] In order to achieve the above object, the present invention provides a flange provided with a pipe mounting hole communicating with each exhaust port of a cylinder head, and a flange fixed to each pipe mounting hole of this flange. In an exhaust manifold having a pipe,
A hollow portion is formed inside a portion of the flange around the joint portion with the pipe.

[For production]

In the present invention, when the engine is started in cold weather, when the engine heats up, the heat of the engine is immediately transferred to the flange, but a hollow part is formed inside the part of the flange around the joint with the pipe. The thermal conductivity of this hollow part is lower than that of the solid metal flange in the conventional example, so the amount of heat transferred from the cylinder head to the flange is small, and the heat The amount of heat conducted from the pipe to the flange is also small. That is, this hollow part has a function like a kind of heat shielding material for the engine.

Further, since a hollow portion is formed inside the portion of the flange around the joint portion with the pipe, the weight of the flange can be reduced and its rigidity can be improved. Therefore, as the pipe deforms due to thermal expansion and contraction, even if a force is generated on the flange that is in contact with the cylinder head to cause its end to curl up from the cylinder head, the highly rigid flange will deform. There aren't many things.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show an exhaust manifold according to a first embodiment of the present invention.

In the figure, 1 is a cylinder head of an engine, and four exhaust ports 2 are formed side by side.

Reference numeral 3 denotes an exhaust manifold according to this embodiment, which has an inflow side flange 4, four pipes 5, and an outflow side gathering flange 6. This exhaust manifold 3 is constructed by passing bolts through a plurality of flange mounting holes 4A provided in the inflow side flange 4 and screwing them onto the cylinder head 1. ) is fixed.

The details of the structure of the above-mentioned inflow side flange 4 and the procedure for assembling it with the pipe 5 will be explained.

The inflow side flange 4 has an upper flange 8, a lower flange 9, and a plurality of spacers 10.

The upper flange 8 is made up of a strip material 8A and a bent portion 8B formed on its periphery, and the strip material 8A has four pipe attachment holes 8C arranged side by side, and a large number of bolt through holes 8D. is drilled.

The lower flange 9 is made up of a strip material 9A and a bent portion 9B formed on its periphery, and the strip material 9A has pipe attachment holes 9C at positions corresponding to the pipe attachment holes 8C of the upper flange 8. Four bolt through holes 9D are formed side by side, and a large number of bolt through holes 9D are formed at positions corresponding to the bolt through holes 8D of the upper flange 8, respectively.

Then, each pipe 5 is passed through each pipe attachment hole 8C of the upper flange 8, and the tip of each pipe 5 is fitted into the outer peripheral surface of the pipe attachment hole 9C of the lower flange 9. Pipe mounting hole 90 of band plate material 9A
Weld the entire circumference and the tip of the pipe 5 W, and then attach the pipe 5.
is fixed to the lower flange 9. Next, a spacer 10 is welded and fixed to each bolt through hole 9D of the lower flange 9, respectively.

Furthermore, push the upper flange 8 into the lower flange 9 and fit it into the pipe attachment hole 8 of the upper flange 8.
C and the pipe 5 are fixed by welding the entire circumference W2, and
The peripheral edge 8E of the upper flange 8 and the tip of the bent portion 9B of the lower flange 9 are fixed by welding W3L.

Thus, a hollow portion H is formed inside the portion of the inflow side flange 4 around the joint portion with the pipe 5.

Further, the bolt through hole 8D, the spacer 10, and the bolt through hole 9D constitute the above-mentioned flange mounting hole 4A, and the spacer 10 prevents the upper flange 8 from being crushed when the exhaust manifold 3 is attached to the cylinder head 1 with bolts. I try not to.

Next, the functions and effects of this embodiment will be explained.

In cold weather, when the engine is started and the engine heats up, the heat of the engine is immediately transferred to the inflow side flange 4, but there is a hollow part inside the part of the inflow side flange 4 around the joint with the pipe 5. H is formed, and the thermal conductivity of this hollow part H is smaller than that of the inflow side flange 102 (shown in FIG. 10) which is made of metal and is solid in the conventional example, so the cylinder head The amount of heat conducted from the heated pipe 5 to the inlet flange 4 is small (and the amount of heat transferred from the heated pipe 5 to the inlet flange 4 is also small.

That is, this hollow part H has a function like a kind of heat shielding material for the engine. Therefore, when starting the engine in cold weather, the escape of heat from the cylinder head 1 is reduced,
The engine can be warmed up quickly, the engine's emission performance at low temperatures can be improved, and exhaust gas purification efficiency can also be improved.

Further, since the hollow portion H is formed inside the portion of the inflow side flange 4 around the joint portion with the pipe 5, the weight of the inflow side flange 4 can be reduced and its rigidity can be improved. Therefore, even if a force is generated in the inflow side flange 4 in contact with the cylinder head 1 to cause its end to be rolled up from the cylinder head 1 due to the deformation of the pipe 5 due to thermal expansion/contraction, the rigidity The inflow side flange 4 with a high value is less likely to deform. In other words, even if a force is applied to the pipe 5 in the direction of the arrow X, the lower flange 9 and the pipe 5 are supported by the upper flange 8, so deformation in the direction of the arrow X is prevented. . As a result, it is possible to restrict the curling up of the end of the inflow side flange 4 and prevent gas leakage.

In this embodiment, a large number of spacers IO are sandwiched between the upper flange 8 and the lower flange 9, but as shown in FIG. It is also possible to eliminate the spacer IO by fixing the inflow side flange 4 to the cylinder head 1 by passing a bolt through the hole 11B provided in the flange 11A and the bolt through hole 9D of the lower flange 9.

Furthermore, in this embodiment, the inflow side flange 4 has an upper flange 8 and a lower flange 9;
In place of the upper flange 8, as shown in FIG. 7, a number of circular lid members 12 corresponding to the pipes 5 are prepared, each having a pipe mounting hole 12A in the center into which the pipe 5 fits. It is also possible to fix the shaped lid member 12 to the lower flange 9 by welding and form the hollow portion H between the circular lid member 12 and the lower flange 9.

Further, in this embodiment, the inflow side flange 4 has an upper flange 8 and a lower flange 9, but instead of the lower flange 9, a pipe 5 is fitted through it, as shown in FIG. A number of circular flange members 13 each having a pipe attachment hole 13A provided in the center thereof are fixed to the upper flange 8 by welding to correspond to the number of pipes 5. 1
A hollow portion H may also be formed between the upper flange 3 and the upper flange 8.

FIG. 9 shows an exhaust manifold according to a second embodiment of the present invention, and only the parts different from the first embodiment will be described. Note that the same reference numerals are given to the same components as those of the first embodiment.

As illustrated, the exhaust manifold 21 according to this embodiment includes an inflow side flange 22 and a plurality of pipes 23. This exhaust manifold 21 is fixed to the cylinder head 1 via a gasket 7 with bolts (not shown).

Details of the structure of the above-mentioned inflow side flange 22 and pipe 23
The fixing structure will be explained below.

The inflow side flange 22 has an upper flange 24, a lower flange 25, and a plurality of spacers 10 (shown in FIG. 4).

The upper flange 24 is made up of a band plate material 24A and a bent portion 24B formed at its peripheral edge.
A plurality of pipe attachment holes 24C are drilled in parallel.

The lower flange 25 is made up of a strip material 25A and a bent portion 25B formed at its peripheral edge, and a plurality of pipe attachment holes 25C are formed side by side in the strip material 25A.

Push the upper flange 24 into the lower flange 25 and fit it into the pipe attachment hole 24 of the upper flange 24.
C and the outer peripheral surface of the pipe attachment hole 25C of the lower flange 25 are fixed by welding the entire circumference W4, and the peripheral edge 24E of the upper flange 24 and the tip of the bent portion 25B of the lower flange 25 are fixed by welding W. has been done.

The pipe 23 is fitted into the inner surface of the pipe attachment hole 25C of the lower flange 25, and the tip of the pipe 23 and the inner circumferential surface of the attachment hole 25C of the lower flange 25 are welded all around by a weld W6.
It's stuck in place.

Thus, a hollow portion H is formed inside the portion of the inflow side flange 22 around the joint portion with the pipe 23.

According to the second embodiment, the effect is similar to that of the first embodiment.

be effective.

〔Effect of the invention〕

As described above, according to the present invention, in cold weather,
When the engine is started and the engine heats up, the engine heat is immediately transferred to the flange, but a hollow part is formed inside the flange around the joint with the pipe.
The thermal conductivity of this hollow part is lower than that of the conventional solid metal flange, so the amount of heat transferred from the cylinder head to the flange is small, and the amount of heat transferred from the hot pipe to the flange is small. The amount of heat conducted to the flange is also small. That is, this hollow part has a function like a kind of heat shielding material for the engine. Therefore, when starting the engine in cold weather, less heat escapes from the cylinder head,
The engine can be warmed up quickly, the engine's emission performance at low temperatures can be improved, and exhaust gas purification efficiency can also be improved.

Further, since a hollow portion is formed inside the portion of the flange around the joint portion with the pipe, the weight of the flange can be reduced and its rigidity can be improved. Therefore, as the pipe deforms due to thermal expansion and contraction, even if a force is generated on the flange that is in contact with the cylinder head to cause its end to curl up from the cylinder head, the highly rigid flange will deform. There aren't many things. As a result, it is possible to restrict curling of the end of the flange and prevent gas leakage.

[Brief explanation of drawings]

FIG. 1 is a sectional view of an exhaust manifold according to a first embodiment of the present invention. FIG. 2 is a perspective view showing the entire exhaust manifold. FIG. 3 is a perspective view of the upper flange of FIG. 2. FIG. 4 is a perspective view of the lower flange of FIG. 2. FIG. 5 is a sectional view taken along the line ■-■ in FIG. 3. 6 is a partial sectional view showing a modification of the upper flange shown in FIG. 3. FIG. FIG. 7 is a perspective view showing a circular lid member replacing the upper flange of FIG. 3. FIG. 8 is a perspective view showing a circular flange member replacing the lower flange of FIG. 4. FIG. FIG. 9 is a sectional view of an exhaust manifold according to a second embodiment of the present invention. FIG. 10 is a perspective view of a conventional exhaust manifold. FIG. 11 is a sectional view of another conventional exhaust manifold. (Explanation of symbols of main parts) 1...Cylinder head 2...Exhaust boat 3...Exhaust manifold 4...Inflow side flange H...Hollow part. Fig. 1 3 (Oi end air manifold) Patent applicant Calsonic Corporation Fig. Fig. Fig. Fig. Fig. 10 Fig. Fig. 1

Claims (1)

[Claims] (1) In an exhaust manifold comprising a flange provided with a pipe mounting hole that communicates with each exhaust port of the cylinder head, and a pipe fixed to each pipe mounting hole of this flange, the pipes of the flange and An exhaust manifold characterized by forming a hollow part inside the part around the joint part.