JPH1089061A - Exhauster with noise eliminating chamber for multicylinder internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of an arranging space in an in-line internal combustion engine which is inclined backward and transversely mounted, by curving downward and extending an exhaust manifold behind the internal combustion engine, and arranging a noise eliminating chamber inside of the curved part of this exhaust manifold. SOLUTION: In an FF car, a series four-cylinder internal combustion engine is transversely mounted in an engine compartment, and a cylinder block is inclined backward. An exhaust pipe is extended per each air cylinder from a cylinder head in the upper part of the cylinder block, however, each exhaust pipe is extended backward from a head flange 25, curved downward and jointed to the joint part 26 of an exhaust manifold 20, and the joint part 26 is connected to a collecting exhaust pipe through a connecting flange 27. The exhaust manifold 20 is so formed that three sheet metal processed plates of a front half body 31, a partitioning body 32 and a rear half body 33 are matched to each other, and a noise eliminating chamber cover 40 is matched and welded to the curved inner end surface of the exhaust manifold 20 so as to section a noise eliminating chamber 41.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system with a silencing chamber in a multi-cylinder internal combustion engine.

[0002]

2. Description of the Related Art As a conventional countermeasure against radiation noise and exhaust noise of an exhaust device of a multi-cylinder internal combustion engine, there is an example in which ceramic wool or the like is interposed between an exhaust manifold and an exhaust manifold cover. The temperature of the exhaust manifold itself becomes too high due to the heat insulation effect, and expensive heat-resistant materials must be used to ensure durability. Further, there is a problem that a large space is taken up by the exhaust manifold cover.

Therefore, there is an example in which a vacant room having an opening is arranged at a position where the exhaust pipe joins. In the conventional example disclosed in Japanese Utility Model Laid-Open No. 5-14524, as shown in FIG. 11, the exhaust manifold 01 has four exhaust pipes 03 extending from a flange 02, and each exhaust pipe 03 is joined at a downstream end. 04 is formed. An empty room 05 having an opening at the junction 04 is formed long along the outermost exhaust pipe 03.

[0004]

In the example shown in FIG. 11, the energy of the sound wave is to be consumed by the resonance action of the empty room 05, but the empty room 05 is located further outside the outermost exhaust pipe 03. Since it is formed so as to bulge out, it is enlarged in the cylinder arrangement direction to take up a large installation space. Also, if the exhaust manifold is made of cast iron, the weight increases.

[0005] The present invention has been made in view of such a point,
It is an object of the present invention to provide an exhaust device with a sound deadening chamber, which is efficient in arrangement space.

[0006]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention relates to an in-line internal combustion engine which is mounted rearwardly and inclined horizontally at the front of a vehicle, wherein an exhaust manifold is provided behind the internal combustion engine. Is curved downward and extends,
A multi-cylinder internal combustion engine is provided with a sound deadening chamber having a sound deadening chamber disposed inside a curved portion of the exhaust manifold.

Since the exhaust manifold extending rearward of the rearwardly inclined internal combustion engine is curved downward, the exhaust manifold is compactly arranged, and an extra space is formed between the curved portion and the internal combustion engine. Since the sound deadening room is arranged by using the surplus space, the space can be effectively used. Since the silencing chamber is provided in the curved portion, sufficient coupling rigidity can be ensured without using a dedicated member separately.

By disposing the exhaust manifold behind the rearwardly inclined internal combustion engine, the length of the exhaust gas passage to the exhaust gas purifying catalyst device (catalytic converter) can be shortened. Exhaust gas reaches the catalytic converter, and the initial function of the exhaust gas purifying catalyst accompanying early activation is improved.

In the exhaust system with a sound deadening chamber of the multi-cylinder internal combustion engine, the exhaust manifold is constituted by abutting three sheet metal members of a front half, a partition, and a back half, and communicates with each cylinder. A plurality of exhaust pipe portions are formed by either the front half or the back half and the partition body, and a merging portion where the exhaust pipe portions merge is formed between the front half, the back half and the intermediate portion. It was formed with the said partition body provided.

[0010] The exhaust manifold is formed of three sheet metal members of a front half, a partition, and a back half, and the exhaust pipe portion is formed of one of the front and back halves and the partition. And the required rigidity is ensured by providing the silencing chamber in the curved portion of the exhaust manifold.

Further, in the exhaust system with a sound deadening chamber of the multi-cylinder internal combustion engine, the exhaust strokes are divided into two groups of inner and outer cylinders whose exhaust strokes are not continuous with each other, and the exhaust pipes communicate with the respective cylinders. The exhaust pipe section is formed by the front half and the partition body, the outer exhaust pipe section is formed by the back half and the partition body, and the sound deadening chamber is formed by the partition body and the back half body. And a plurality of communication holes communicating with the muffling chamber are formed in the back half of the junction.

By forming a communication hole communicating with the noise reduction chamber in the back half of the junction, the noise reduction chamber is communicated through the communication hole with the junction of the outer exhaust pipe portion, and the length of the conduit is structurally reduced to the inner exhaust pipe. By increasing the substantial passage length of the exhaust pulsation wave of the outer exhaust pipe portion longer than the inner exhaust pipe portion to the inner exhaust pipe portion, it is possible to prevent an increase in exhaust noise due to resonance. Further, by providing a suitable number of communication holes having a suitable size, it is possible to reduce exhaust sound and radiation sound in a specific frequency region where sound reduction is required.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. The vehicle 1 according to the present embodiment is an FF (front engine front drive) vehicle, and FIG. 1 is a schematic side view showing an arrangement state of an internal combustion engine 10 at a front portion of the vehicle body.

In the engine room 3 below the hood 2, an in-line four-cylinder internal combustion engine 10 is mounted horizontally between a front radiator 4 and a rear dashboard 5, and the cylinders are arranged in series. The cylinder block 11 is inclined rearward. An intake manifold 15 extends forward from a cylinder head 12 above the cylinder block 11 that is tilted rearward, and an exhaust manifold 20 extends rearward.

The four cylinders of the in-line four-cylinder internal combustion engine 10 mounted horizontally on the vehicle body are arranged in order from the right side (the right side in the vehicle traveling direction) as first, second, third, and fourth cylinders. Then, the first cylinder and the fourth cylinder constitute a cylinder group in which the exhaust stroke is not continuous, and similarly, the second cylinder and the third cylinder constitute another cylinder group in which the exhaust stroke is not continuous.

From the cylinder head 12 of the in-line four-cylinder internal combustion engine 10, the first, second, third, and fourth exhaust pipes 21, 22, 23, and 24 are provided for each of the first, second, third, and fourth cylinders. Extends rearward. Four first, second, third and fourth exhaust pipes 21, 22, 2
3, 24 are connected to the cylinder head 12 with their base ends fitted and supported by a common horizontally long plate-shaped head flange 25.

First, second, third, and fourth exhaust pipes 21, 22, 2
3 and 24 extend rearward from the head flange 25, curve downward and join the central junction 26, and the junction 26 of the exhaust manifold 20 is connected to a single junction via a connection flange 27. The catalytic converter 29 is connected to the exhaust pipe 28 and downstream of the collective exhaust pipe 28.

As shown in FIG. 4, the exhaust manifold 20 is formed by abutting three sheet metal plates of a front half body 31, a partition body 32, and a back half body 33. Referring to FIG. 5 and FIG. 6, the front half body 31 is provided with two inner second and third exhaust pipes 22,
The front side (upper side) second and third half walls 31a and 31b of the 23 and the front side half wall 31e of the merging section 26 are constituted, and the front and second half walls 31a and 31b are adjacent to each other. And are parallel and similarly curved.

Referring to FIG. 7 and FIG. 8, the partition 32 is provided on the back (lower) second side of the two inner second and third exhaust pipes 22, 23.
The third half-walls 32a, 32b are connected to each other, and the first and fourth half-walls 32c on the front side of the two outer first and fourth exhaust pipes 21, 24 are formed.
32d is formed outside the back side second and third half walls 32a and 32b, and the merging partition wall 32e of the merging portion 26 is
a, 32b, 32c, and 32d are collectively formed, and are entirely curved. An attachment hole 32f for fixing the oxygen sensor is formed in the merging partition wall 32e.

Referring to FIG. 9 and FIG. 10, the back half 33 is formed by joining the rear first and fourth half walls 33c and 33d of the two outer first and fourth exhaust pipes 21 and 24 to the junction 26. And is branched right and left from the rear half-wall half 33e. An attachment hole 33f for the oxygen sensor is formed in the center of the back-side merging half wall 33e, and communication holes 33g and 33h are formed in the vicinity of the merging portion of each of the back-side first and fourth half-walls 33c and 33d.

The above-mentioned front half body 31, partition body 32 and back half body 33 are
As shown in FIG. 4, when the parts are butt-welded to each other in a predetermined positional relationship from the top in order, the front and second half-walls 31 a and 31 b of the front half 31 and the second and third half-walls of the partition 32 are separated. The three half walls 32a and 32b are united to form two inner second and third exhaust pipes 22 and 23, and the first and fourth half walls 33c and 33d on the back side of the back half 33 and the partition 32. Front side first and fourth half-walls 32c,
32d are combined to form two outer first and fourth exhaust pipes 21, 24.

The merging partition wall 31e of the front half 31 and the back merging half wall 33e of the back half 33 are joined to the merging partition wall 32 of the partition body 32.
e is sandwiched at the center to form a merging portion 26. Therefore, the passage where the two inner and second exhaust pipes 22 and 23 merge and the outer two first and fourth exhaust pipes 21 and 24 are formed. Is divided by a partition wall 32e to the downstream end of the junction 26, and the two gather at the downstream end of the junction 26.

The second and third exhaust pipes 22 and 23 communicate with cylinders whose exhaust strokes are not continuous with each other.
Since the cylinders 21 and 24 also communicate with cylinders whose exhaust strokes are not continuous, exhaust interference is avoided.

The exhaust manifold 20 is thus formed, and a silencing chamber cover 40 is abutted against the curved inside of the exhaust manifold 20 and welded to form a silencing chamber 41. The silencing chamber cover 40 has a box shape as shown in FIG.
The opening peripheral edge 40a is the second and third half-walls 32a on the back side of the partition 32.
When the lower surface of the lower half 32b and the lower half of the rear half half wall 33e of the back half 33 are abutted against each other, they come into airtight contact with the second and third half rear walls 32a, 32b and the rear half split wall. The muffler chamber 41 is formed inside the muffler chamber cover 33e.

The muffling chamber cover 40 covers the two communication holes 33g and 33h of the back-side converging half wall 33e, and the inside of the muffling chamber 41 has two outside first and first communication holes 33g and 33h, respectively. The fourth exhaust pipes 21 and 24 communicate with each other.

The sound deadening chamber 41 is filled with ceramic wool, which is a fibrous sound deadening material. An oxygen sensor is fitted into the mounting hole 33f of the back half 33 from below, and the partition 32
And supported by the mounting holes 32f.

The exhaust manifold 20 thus formed is
A head flange 25 is welded to the upstream end of the first, second, third, and fourth exhaust pipes 21, 22, 23, and 24, and is fixed to the cylinder head 12 of the internal combustion engine 10.

The internal combustion engine 10 is inclined rearward, and an exhaust manifold 20 extending rearward from the cylinder head 12 is provided.
Is curved downward, so that the exhaust manifold 20 is compactly arranged. Although an extra space is formed between the curved portion of the exhaust manifold 20 and the internal combustion engine, the noise reduction chamber 41 is disposed in the extra space, so that the space can be used effectively.

By arranging the exhaust manifold 20 behind the rearwardly inclined internal combustion engine 10, the length of the exhaust gas passage up to the catalytic converter 29 can be shortened. 29, the initial function of the exhaust gas purifying catalyst accompanying the early activation can be improved.

Since the exhaust manifold 20 is constructed by abutting three sheet metal front half 31, partition 32, and back half 33, the manufacturing is simplified, the weight can be reduced, and the fuel efficiency can be improved. Can be expected.

In particular, the second and third exhaust pipes 22 and 23 are formed by the front half 31 and the partition 32, and the first and fourth exhaust pipes 21 and 24 are formed.
Is formed by the back half 33 and the partition 32, each of which consists of the union of upper and lower halves, and does not increase the weight by using two halves in layers. It is possible to reduce the weight by forming the entire body to be thin while maintaining the required strength and rigidity. In addition, the reduction in the thickness of the entire body makes it possible to accelerate the start of the catalytic action of the catalytic converter 29 due to the rapid temperature rise.

Further, the merging portion 26 is a portion where the exhaust gas temperature becomes the highest, and the most rigid portion is provided by providing a sound deadening chamber 41 in such a portion and making the plate 32 of the partition body 32 thicker than the front and back halves 31, 33. By attaching the muffling chamber 41 to the partition member 32 having a high height, the joining rigidity of the sheet metal member can be secured without using a dedicated member separately, so that the sheet metal member can be resistant to vibration and the durability can be improved.

The distance between the inner second and third exhaust pipes 22 and 23 and the outer first and fourth exhaust pipes 21 and 24 is smaller than the distance between the inner first and fourth exhaust pipes 22 and 23. Although the length of the first and fourth exhaust pipes 21 and 24 is longer than the length of the first and fourth exhaust pipes 21 and 24, a communication hole is provided.
33g and 33h, and the first and fourth exhaust pipes 2
The communication holes 33g and 33h in front of the junctions 1 and 24 form nodes of exhaust pulsation waves, and have substantially the same passage length as the inner second and third exhaust pipes 22 and 23. Therefore, it is possible to prevent an increase in exhaust sound due to resonance.

Also, by appropriately setting the hole diameter, hole length and number of the communication holes 33g and 33h, the capacity of the sound deadening chamber 41, and the filling amount and density of the sound deadening material, the exhaust sound and radiation sound in a specific frequency range can be reduced. can do.

The noise reduction chamber 41 is capable of reducing exhaust noise, especially high-frequency noise, and the radiation noise generated in the noise reduction chamber 41 is cut off by the exhaust manifold 20, the rearwardly inclined internal combustion engine 10 and the dashboard 5, and You can keep quiet.

[0036]

According to the present invention, the exhaust manifold extending rearward of the rearwardly inclined internal combustion engine is curved downward, so that the exhaust manifold is compactly disposed and the space between the curved portion and the internal combustion engine is reduced. Since a surplus space is formed in the space, and the silencer is arranged using the surplus space, the space can be used effectively. Since the silencing chamber is provided in the curved portion, sufficient coupling rigidity can be ensured without using a dedicated member separately.

By arranging the exhaust manifold behind the rearwardly inclined internal combustion engine, the length of the exhaust gas passage to the exhaust gas purifying catalyst device (catalytic converter) can be shortened. The exhaust gas reaches the catalytic converter, and the initial function of the exhaust gas purifying catalyst accompanying early activation is improved.

The exhaust manifold includes a front half, a partition,
Since the back half is formed of three sheet metal members, and the exhaust pipe portion is formed of one of the front and back halves and the partition body, the weight of the exhaust device can be reduced, and the exhaust manifold can be curved. The required rigidity is ensured by providing the silencing chamber in the section.

Further, by forming a communication hole communicating with the muffling chamber in the rear half body at the junction, the actual path length of the exhaust pulsation wave of the outer exhaust pipe is made equal to that of the inner exhaust pipe, and the exhaust noise due to resonance is formed. Can be prevented from increasing. Further, by providing a suitable number of communication holes having a suitable size, it is possible to reduce exhaust noise and radiation sound in a specific frequency range where noise reduction is required.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an arrangement state of an internal combustion engine at a front portion of a vehicle body of an automobile according to an embodiment of the present invention.

FIG. 2 is a rear view of an exhaust manifold of the internal combustion engine.

FIG. 3 is a sectional view taken along the line III-III in FIG. 2;

FIG. 4 is an exploded perspective view of an exhaust manifold.

FIG. 5 is a rear view of the front half.

FIG. 6 is a side view of the same.

FIG. 7 is a rear view of the partition body.

FIG. 8 is a side view of the same.

FIG. 9 is a rear view of the back half.

FIG. 10 is a side view of the same.

FIG. 11 is a front view of a conventional exhaust manifold.

[Description of Signs] 1 ... Automobile, 2 ... Bonnet, 3 ... Engine room, 4 ... Radiator, 5 ... Dashboard, 10 ... Internal combustion engine, 11 ... Cylinder block, 12 ... Cylinder head, 15 ... Intake manifold, 20 ... Exhaust Manifold, 21 first exhaust pipe, 22 second exhaust pipe, 23 third exhaust pipe, 24 fourth exhaust pipe, 25 head flange, 26 junction, 27 connection flange, 28 exhaust pipe , 29 ... catalyst converter, 31 ... front half body, 32 ... partition body, 33
... back half, 40 ... muffler room cover, 41 ... muffler room.

Claims (3)

[Claims] 1. An in-line internal combustion engine which is mounted rearwardly and inclined horizontally at a front portion of a vehicle, wherein an exhaust manifold is curved downward and extends rearward of the internal combustion engine, and an inside of a curved portion of the exhaust manifold is provided. An exhaust system with a muffler chamber for a multi-cylinder internal combustion engine, wherein a muffler chamber is arranged in the exhaust system. 2. The exhaust manifold is formed by abutting three sheet metal members of a front half, a partition, and a back half with each other, and a plurality of exhaust pipes communicating with each cylinder are formed of the front half or the exhaust half. It is formed of one of the back halves and the partition body, and a merging portion where the exhaust pipes merge is formed by the front half body, the back half body, and the partition body provided therebetween. The exhaust device with a muffler chamber for a multi-cylinder internal combustion engine according to claim 1. 3. An exhaust process is divided into two groups of cylinders, the inside and outside of which are not continuous with each other. The exhaust pipes communicate with each of the cylinders, and the inner exhaust pipe of the exhaust pipes is separated from the front half by the partition. An outer exhaust pipe portion is formed by the back half and the partition; the muffler chamber is formed on a lower surface of the partition and the back half; The exhaust device with a muffle chamber for a multi-cylinder internal combustion engine according to claim 2, wherein a plurality of communication holes communicating with the muffle chamber are formed in the half body.