JP3318696B2 - Exhaust gas purification device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purifying apparatus for an internal combustion engine.

[0002]

2. Description of the Related Art An exhaust gas purifying catalyst (a catalyzer) is generally provided in an exhaust system of an internal combustion engine for a vehicle or the like. For example, a noble metal such as Pt (platinum) or Rh (rhodium) is used as a catalyst component to form a ceramic. A catalyzer supported on a carrier is generally used. However, the catalyzer does not function sufficiently until a predetermined activation temperature is reached, and therefore, there is a problem in exhaust gas purification performance at the time of a cold start or the like.
Therefore, attempts have been made to increase the catalyst activation rate by directly connecting a catalyzer to the exhaust manifold outlet on the upstream side where the gas temperature is high so that the catalyzer is exposed to high-temperature exhaust gas. A so-called metal catalyzer is suitable as the catalyzer directly attached to the exhaust manifold. The metal catalyzer is obtained by supporting a catalyst component on a honeycomb-shaped carrier formed by winding a metal flat plate and a corrugated plate. Japanese Utility Model Laid-Open Publication No. 61-181817 discloses an example of an exhaust gas purifying apparatus for an internal combustion engine in which a catalyzer is directly connected to an exhaust manifold. In the case of the exhaust gas purifying apparatus disclosed in this publication, means for turning exhaust gas is provided between the exhaust outlet end of the exhaust manifold and the catalyzer, and uniform exhaust gas is introduced to the upstream end of the catalyzer by turning the exhaust gas. I have.

[0003]

In a multi-cylinder internal combustion engine having a plurality of cylinders arranged in the direction of the output shaft, an exhaust manifold has a plurality of independent passages connected to exhaust ports of each cylinder, and a plurality of independent passages. It is normal to be configured with a collecting part that collects one, but when a catalyzer is directly connected to the exhaust manifold of such a multi-cylinder internal combustion engine, it is discharged from the intake port of each cylinder and passes through each independent passage. Exhaust gas that merges through the exhaust manifold via the exhaust manifold flows into the catalyzer without being sufficiently diffused. In the case of such a multi-cylinder internal combustion engine, the flow of exhaust gas flowing through the independent passages of the exhaust manifold and reaching the collecting portion is not uniform among the cylinders. For example, some of the cylinders are located at positions close to the collecting portion. The main flow of exhaust gas passes through the axis of the independent passage and flows to the collecting portion, and another cylinder is located at a position distant from the collecting portion, and the main flow of exhaust gas flows toward the tangent at the exhaust outlet end In this case, the exhaust gas from the partial cylinder directly flows into the catalyzer at a high temperature, and the exhaust gas from the other cylinders is cooled while being cooled along the inner wall of the exhaust outlet end of the exhaust manifold and the exhaust inlet end of the catalyzer. Flows into. For this reason, deterioration due to heat proceeds in a portion where the exhaust gas hits at a high temperature, and the temperature gradient of the cater carrier near the exhaust introduction end becomes large, so that cracks are easily generated. In addition, if the exhaust gas of each cylinder flows into the upstream portion of the catalyst in a non-uniform state without being sufficiently diffused, the reaction area of the catalyst is not effectively used, and thus sufficient catalytic performance cannot be obtained.

[0004] As described above, a device provided with a means for turning exhaust gas between an exhaust outlet end of an exhaust manifold and a catalyzer is known. However, if such a swivel device is provided, the structure of the exhaust manifold or the catalyzer becomes complicated, so that practical use is difficult.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, and it is possible to prevent a crack caused by heat of exhaust gas from being generated in a catalyzer directly attached to an exhaust manifold. An object is to allow the fluid to flow uniformly.

[0006]

The invention according to claim 1 is
A multi-cylinder internal combustion engine in which a plurality of cylinders in the output shaft direction, set to a set and a plurality of independent passages each connected to an exhaust port of each cylinder of the internal combustion engine, a plurality of independent passages into one And an exhaust manifold having a portion, and a range of an output axial direction length of the exhaust manifold.
In, and is disposed at one end of the output shaft direction, in the exhaust purification apparatus directly connected thereto catalyzer the Bei <br/> obtain an internal combustion engine to the collecting portion of the exhaust manifold, the Kyatarai
The exhaust introduction end of the
The exhaust output end of the gathering portion of the field is also formed in a substantially circular shape.
The catalyzer is located among the plurality of independent passages.
Connected to the exhaust port of some cylinders at one end in the output shaft direction
In the independent passage, the main flow of exhaust gas from the independent passage is linear.
Into the catalyzer at the beginning and other independent communication
The main flow of the exhaust gas from the independent passage to the substantially circular shape.
Upward at the tangent on the side near the internal combustion engine at the exhaust outlet end
And connected to the exhaust port of the partial cylinder.
Exhaust manifold opposing the main flow of exhaust gas from the independent passage
The inner wall portion of the fuel cell and the partial cylinder
Partially in the range of the exhaust gas flow,
Providing the deflecting means for deflecting the main <br/> exhaust gas from the independent passages connected to the exhaust port, characterized in.

According to a second aspect of the present invention, there is provided a vehicle control system comprising:
A multi-cylinder internal combustion engine having a plurality of cylinders arranged therein.
Multiple independent ports connected to the exhaust ports of each cylinder
A passage and a set that aggregates these multiple independent passages into one
And an exhaust manifold having a
The exhaust manifold is located within the length of the output
Catala directly connected to the assembly of the air manifold
An exhaust purification device for an internal combustion engine having a
Exhaust flow through the independent passages
Exhaust of some cylinders flowing straight into the catalyzer
Exhaust port, which is opposed to the exhaust flow from the exhaust port.
Deflecting means for deflecting the exhaust flow to the inner wall of the gas manifold
The provided on said deflection means, characterized in that a communication passage communicating the upstream side and the catalyzer side.

[0008]

According to the structure of the present invention, the exhaust ports of a part of the exhaust ports of a plurality of cylinders, from which the exhaust flow linearly flows into the catalyzer via the independent passage, are exhausted. By providing a deflecting means for deflecting the exhaust flow in the exhaust manifold inner wall portion facing the flow, the exhaust flow from the partial cylinder is deflected by the deflecting means, and flows straight into the catalyzer at a high temperature. Is prevented. Therefore, the deterioration of the catalyzer due to the heat of the exhaust gas is suppressed, the temperature gradient is reduced, and the occurrence of cracks is prevented. Also, the exhaust stream diffuses and flows uniformly into the catalyzer, thereby effectively utilizing the reaction area of the catalyst and enhancing the catalyst performance.

In particular, the exhaust introduction end of the catalyzer is formed in a substantially circular shape, and the exhaust outlet end of the gathering portion of the exhaust manifold is also formed in a substantially circular shape. The main flow of the exhaust gas from the partial cylinder passes on the axis of the independent passage of the cylinder toward the deflecting means, and the main flow of the exhaust gas from the other cylinder contacts the exhaust outlet end of the circular shape. The above-mentioned effect is remarkable when it is comprised so that it may go on a line.

[0010] In addition, the desired action can be obtained by providing the deflection means partially in the range of the flow of the exhaust gas from the partial cylinder.

Further , when the deflecting means has a communication path for communicating the upstream side with the catalyzer side, the pressure balance between the upstream and downstream of the deflecting means is maintained, and the exhaust gas flows behind the deflecting means and becomes catalyzed. Evenly flows into the upstream end.

[0012]

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

FIG . 1 is a partially cutaway overall view of an exhaust gas purifying apparatus for an internal combustion engine showing one embodiment of the present invention, FIG. 2 is a front view of the exhaust manifold of the embodiment shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a plan view of the exhaust manifold of the embodiment, FIG. 4 is a rear view of the exhaust manifold of the embodiment shown in FIG. 1, FIG. 5 is a left side view of the exhaust manifold of the embodiment shown in FIG. 1, and FIG. A
FIG. 7 is a sectional view taken along line B of FIG. 8 is a schematic diagram illustrating the flow of exhaust gas in the embodiment shown in FIG. 1, and FIG. 9 is a cross-sectional view according to a modification of the embodiment shown in FIG.

In FIG . 1, reference numeral 1 denotes an exhaust manifold, and reference numeral 2 denotes a metal catalyzer directly attached to the exhaust manifold 1. The exhaust manifold 1 is attached to one bank of a V-type 6-cylinder engine, and has independent passages 3A, 3B, 3C connected to exhaust ports of three cylinders arranged in the output shaft direction. Passages 3A, 3
B and 3C are gathered together on the downstream side. The collecting portion 4 is arranged at one end of the exhaust manifold 1 in the range of the length in the output shaft direction, has a structure bent downward in a side view, and has a substantially circular bottom end in a throat shape in a plan view. The exhaust outlet end 4a has a diameter. The outer peripheral end of the exhaust outlet end 4a has a caterer connecting portion 1a.
Is provided.

[0015] each of the independent passage 3A of the exhaust manifold 1, 3
B and 3C indicate that the main flow of the exhaust gas from the one end cylinder passes through the axis of the independent passage 3A of the cylinder and flows into the collecting portion 4 when viewed from above, and the exhaust gas from the other cylinders The main flow is configured to be directed to a tangent to the substantially circular exhaust outlet end 4a. Also, the above-mentioned collecting part 4 of the exhaust manifold 1
A weir 5 having a structure in which the inner wall is partially protruded is provided at the inlet portion of the exhaust outlet end 4a whose diameter increases in a throat shape. This weir 5 is in the range of the flow of the exhaust gas flowing from the cylinder closest to the collecting portion 4 and therefore to the metal cater 2 through the independent passage 3A, and connects the independent passages 3B and 3C from the other cylinders. The exhaust gas is deflected substantially in parallel with the swirl flow generated by the exhaust gas flowing through the exhaust gas. In addition, the weir 5 is provided with a communication path 6 that communicates the upstream side and the downstream side (cater side).

The exhaust manifold 1 is provided with reinforcing ribs 1b extending in the direction of the output shaft protruding from the front outer wall of the independent passages 3A, 3B and 3C.
A sensor hole 1c is provided at a position upstream of the weir 5 where exhaust flows from each cylinder intersect. An air-fuel ratio sensor 7 is attached to the sensor hole 1c. By providing the reinforcing ribs 1b in the output shaft direction in this manner, rigidity against thermal deformation appearing in the opposite direction between a cold state and a high temperature state is increased, and the sealing performance on the cylinder head mounting surface is secured. It will be easier. Further, the air-fuel ratio sensor 7 is disposed at a position where the exhaust gas with each other Mazari from each cylinder, air fees
This is convenient for debug control.

The metal catalyzer 2 is formed by supporting a catalyst component on a honeycomb-shaped carrier 8 formed by winding a metal flat plate and a corrugated plate. The contact between the lithographic plate and the corrugated plate is brazed in the range of several turns. For example, a region s outside the one-dot chain line in FIG. 1 is a brazing range. Metal Cat 2
The substantially circular upstream end of the cylindrical cater case 10 surrounding the carrier 8 is fitted into the cat connector 1a of the exhaust manifold 1 and is electrically welded. Reference numeral 16 in FIG. 1 is the welded portion. The cater case 10 covers the entire outer periphery of the carrier 8, and has a lower end joined to the carrier 8 by brazing. The lower end of the cater case 10 is fitted into an outlet cone 17 connected to an exhaust pipe (not shown) and is joined by electric welding. Reference numeral 18 in FIG. 1 is the welded portion. The glass wool 14 is disposed on the outer peripheral surface of the cater case 10 and is held by a guide 19 having a U-shaped cross section and a two-part structure. The guides 19 are integrally connected to each other by bolts (not shown) while holding the glass wool 14 on the outer peripheral surface of the metal cater 6.
Is fixed by spot welding.

[0018] the weir 5 provided to the set portion 4 of the exhaust manifold 1 and the exhaust as shown in Figure 9 the manifold 1
Without changing the wall thickness, the outer wall may be recessed inward, and various other designs are possible. Further, the communication path 6 does not necessarily have to be provided.

In the above embodiment, a V-type engine has been described. However, the present invention can be applied to an in-line engine.
Further, the catalyzer directly attached to the exhaust manifold is not limited to the metal catalyzer.

[0020]

Since the present invention is constructed as described above, it is possible to prevent cracks due to the heat of the exhaust gas from being generated in the catalyzer directly attached to the exhaust manifold. Can be made to flow uniformly.

In particular , among the exhaust ports of a plurality of cylinders, the exhaust manifold of one of the cylinders in which the exhaust flow linearly flows into the catalyzer via an independent passage is opposed to the exhaust flow from the exhaust port. By providing the deflecting means for deflecting the exhaust flow on the inner wall portion, the exhaust flow from the partial cylinder can be deflected by the deflecting means to prevent the exhaust gas from flowing straight into the catalyzer at a high temperature. This suppresses the deterioration of the catalyzer due to the heat of the exhaust gas, reduces the temperature gradient to prevent the occurrence of cracks, diffuses the exhaust flow sufficiently and allows it to flow uniformly into the catalyzer, thereby increasing the catalytic reaction area. To enhance the catalytic performance.

Further, the exhaust introduction end of catalyzer is formed in a substantially circular shape, the exhaust outlet end of the collecting portion of the exhaust manifold is also formed in a substantially circular shape, each independent passages of the exhaust manifold, the viewed from the top one The main flow of the exhaust gas from the cylinder passes through the axis of the independent passage of the cylinder to the deflecting means, and the main flow of the exhaust gas from the other cylinder flows on the tangent to the circular exhaust outlet end. The above-mentioned effect can be made remarkable when it is comprised so that it may face.

Further, by partially providing the deflecting means in the range of the flow of exhaust gases from the partial-cylinder it can as achieve the above effects.

Further , by providing a communication path for communicating the upstream side of the deflecting means and the catalyzer side, the pressure balance between the upstream and downstream of the deflecting means can be maintained, and the exhaust gas can uniformly flow into the upstream end of the catalyzer. .

[Brief description of the drawings]

FIG. 1 is a partially cutaway overall view of an exhaust gas purifying apparatus for an internal combustion engine, showing an embodiment of the present invention.

FIG. 2 is a front view of the exhaust manifold of the embodiment shown in FIG.

FIG. 3 is a plan view of the exhaust manifold of the embodiment shown in FIG.

FIG. 4 is a rear view of the exhaust manifold of the embodiment shown in FIG. 1;

FIG. 5 is a left side view of the exhaust manifold of the embodiment shown in FIG. 1;

FIG. 6 is a sectional view taken along line AA of FIG. 2;

FIG. 7 is a view taken in the direction of arrow B in FIG. 5;

FIG. 8 is a schematic diagram illustrating the flow of exhaust gas in the embodiment shown in FIG.

FIG. 9 is a sectional view according to a modification of the embodiment shown in FIG. 1;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Exhaust manifold 2 Metal catalyzer (catalyzer) 3A, 3B, 3C Independent passage 4 Collecting part 4a Exhaust outlet end 5 Weir (deflection means) 6 Communication passage

Continuation of front page (72) Inventor Akio Taniguchi 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (72) Inventor Hiroaki Sugiura 3-1 Shinchi, Fuchu-cho, Aki-gun, Hiroshima Mazda Corporation (72) Inventor Tsutomu Nakayama 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Co., Ltd. (56) References: Japanese Utility Model Application No. Sho 61-181817 (JP, U) Japanese Utility Model Application No. Sho 60-36518 (JP, U) Japanese Utility Model Application 55-104712 (JP, U) Japanese Utility Model Application 58-189314 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F01N 3/24-3/28 F01N 7/10

Claims (2)

(57) [Claims] 1. A multi-cylinder internal combustion engine in which a plurality of cylinders in the output shaft direction and a plurality of independent passages each connected to an exhaust port of each cylinder of the internal combustion engine, a plurality of independent passages one with an exhaust manifold and a collecting portion which set to one, the range of the output shaft direction length of the exhaust manifold, and is disposed at one end of the output shaft direction, and is connected directly to the collecting portion of the exhaust manifold in the exhaust purification system for an internal combustion engine having a catalyzer, to form an exhaust introduction end of said catalyzer in a substantially circular shape, before
The exhaust output end of the collecting part of the exhaust manifold is also substantially circular.
And the catalyzer is located among the plurality of independent passages.
Connected to the exhaust port of some cylinders at one end in the output shaft direction.
The main passage of the exhaust gas from the independent passage is linear.
And the main flow of the exhaust gas from the independent passage is
A substantially circular exhaust outlet end near the internal combustion engine
It is configured to go tangentially, and from an independent passage connected to the exhaust port of the partial cylinder.
In the collection section of the exhaust manifold facing the main flow of exhaust gas
Exhaust gas flow from the partial cylinder
Partially connected to the exhaust port of the partial cylinder
An exhaust gas purifying apparatus for an internal combustion engine, comprising a deflecting means for deflecting a main flow of exhaust gas from an independent passage . 2. A multi-cylinder in which a plurality of cylinders are arranged in an output shaft direction.
A cylinder internal combustion engine, wherein an exhaust port of each cylinder of the internal combustion engine is provided.
And a plurality of independent passages respectively connected to the
Exhaust manifold having a collecting part for collecting independent passages into one
Hold and output of the exhaust manifold
The exhaust manifold is disposed in the axial length range,
Internal combustion engine with catalyzer directly connected to the collecting part
In the exhaust gas purifying apparatus, the exhaust gas flows through an independent passage among the exhaust ports of the plurality of cylinders.
Part of the cylinder that flows straight into the catalyzer via
With respect to the exhaust port, facing the exhaust flow from the exhaust port
To deflect the exhaust flow to the inner wall of the exhaust manifold
The deflecting means is provided, on the deflection means, the exhaust gas purifying apparatus for an internal combustion engine, characterized in that a communication passage communicating the upstream side and the catalyzer side.