JP2001050043A - Exhaust emission control system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an emission control system capable of disposing a catalyst without the need for large space. SOLUTION: A cylindrical portion 31 to be inserted in a branch pipe 23 of an exhaust manifold 2 is disposed on a gasket 22. A catalyst layer 33 is provided on an inner wall 31a and an outer wall 31b of the cylindrical portion 31. Since the catalyst layer 33 is provided on the cylindrical portion 31 to be inserted in the branch pipe 23, large space is not necessary for disposing it. Further, since exhaust gas to contact with the catalyst layers 33 is directly emitted from an engine 1 thus having a high temperature, a catalyst function is activated early, which improves purification performance. Furthermore, since the catalyst layer 33 is provided on the cylindrical portion 31 and thus ventilation resistance is little, an output of the engine 1 can be retained at a satisfactory level without deteriorating performance of a turbocharger 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purification device used for a vehicle or the like.

[0002]

2. Description of the Related Art FIG. 7 shows an example of a conventional exhaust gas purifying apparatus. In this exhaust gas purification apparatus, an exhaust pipe 3 is connected to an exhaust manifold 2 provided in an engine (internal combustion engine) 1, and a catalytic converter 4 (under-floor catalyst) is interposed in a portion of the exhaust pipe 3 that is arranged below the floor of the vehicle. ing. In recent years, exhaust gas regulations have become strict, and accordingly, a catalytic converter 4 (warm-up catalyst) has been provided in a portion of the exhaust pipe 3 near the engine 1 as shown in FIG. 8, the catalytic converter 4 is attached near the engine 1, so that the catalytic converter 4 (warm-up catalyst) is immediately heated and activated immediately after the engine 1 starts to purify harmful gas components. be able to.

[0003]

The exhaust gas purifying apparatus shown in FIG. 8 cannot be adopted unless there is a space in the engine room (not shown) where a catalytic converter 4 (warm-up catalyst) and the like can be arranged. , And it is constrained accordingly. In particular, for example, in the engine 1 with the turbocharger 5 as shown in FIG. 9, since the turbocharger 5 is arranged in the engine room (not shown), the catalytic converter 4
Arrangement becomes more difficult. In FIG. 9, the turbocharger 5 is connected to an exhaust manifold 2 connected to a cylinder head 6 of the engine 1, and is operated using the energy of exhaust gas from the engine 1 to improve the density of intake air to the engine 1. I try to plan. An exhaust pipe 3 is connected to the turbocharger 5, and a catalyst (catalytic converter 4) is interposed in the exhaust pipe 3. In FIG. 9, 7 is an air cleaner, 8 is a PCV valve, 9 is an intercooler, 10 is a throttle sensor, 11 is a fuse type temperature sensor, 12 is an engine control unit, and the engine control unit 12 is an injector 13, an intake sound sensor 14, water temperature sensor 15, knock sensor 16, O ₂ sensor 17, the warning light 1
8, EGR valve 19, ignition coil 20, distributor 21 and the like.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an exhaust gas purification apparatus in which a catalyst can be arranged without securing a large space.

[0005]

According to the first aspect of the present invention,
A gasket interposed between an internal combustion engine and an exhaust manifold connected to the internal combustion engine is provided with a tubular portion inserted into a passage of the exhaust manifold, and a catalyst layer is provided in the tubular portion. I do. According to a second aspect of the present invention, in the configuration according to the first aspect, a gap is formed between a wall surface of the passage and the cylindrical portion, and the catalyst layer is formed on both surfaces of the cylindrical portion. According to a third aspect of the present invention, in the configuration of the second aspect, a plurality of holes are formed in the cylindrical portion.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An exhaust gas purifying apparatus according to a first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, an exhaust manifold 2 is connected to a cylinder head 6 of a four-cylinder engine 1 (internal combustion engine) via a metal gasket (hereinafter, referred to as a gasket) 22.
Is connected. A turbocharger 5 connected to the exhaust pipe 3 (see FIG. 9) is connected to the exhaust manifold 2. The exhaust manifold 2 has four branch pipes 23 corresponding to the four-cylinder engine 1, and an exhaust manifold body having an opening 24 that collectively connects the four branch pipes 23 and connects to the turbocharger 5. And a section 25. A flange 26 is formed on the opening side (connection side with the engine 1) of the four branch pipes 23. The gasket 22 is interposed between the flange 26 and the cylinder head 6, and is fixed to the cylinder head 6 of the engine 1 together with the exhaust manifold 2 by bolts 27.

The gasket 22 has a long and plate-shaped gasket body 29 interposed between the flange 26 and the cylinder head 6 and including four exhaust ports 28 of the engine 1. Four holes (exhaust holes) 30 are formed in 29 so as to communicate with the exhaust port 28 of the engine 1 and the opening 23 a of the branch pipe 23. The gasket main body 29 is formed with a cylindrical tubular portion 31 corresponding to the four exhaust holes 30.
Is to be inserted into. The outer diameter of the cylindrical portion 31 is smaller than the inner diameter of the branch pipe 23, and
3 and a gap 32 between itself and the inner wall of the branch pipe 23.
Are formed.

The inner wall surface 31a and the outer wall surface 31b of the cylindrical portion 31
A layer (catalyst layer) 33 made of a catalyst is provided on both surfaces by coating or the like, and a catalytic action is exhibited by contact with the exhaust gas to purify the exhaust gas.

In the exhaust gas purifier configured as described above, when the exhaust gas from the engine 1 passes through the cylindrical portion 31, the exhaust gas is purified by the catalytic action of the catalyst layer 33. For example, when the catalytic converter 4 is provided downstream of the turbocharger 5 as shown in FIG. 9, heat is taken by the turbocharger 5 and the temperature of the exhaust gas flowing into the catalytic converter 4 decreases, so that the catalytic converter 4 Although it takes time to activate the catalyst, in the present embodiment, the catalyst layer 33 is provided immediately after the exhaust port 28 of the engine 1, and the exhaust gas contacts the catalyst layer 33 at a high temperature. As a result, the catalyst function is activated earlier and the purification performance is improved accordingly. Also, the inner wall surface 31 of the cylindrical portion 31
a and the catalyst layer 33 is provided on both surfaces of the outer wall surface 31b,
The contact area with the exhaust gas is large. For this reason,
The amount of purification of exhaust gas can be increased.

Since the catalyst layer 33 is provided on the cylindrical portion 31 and the exhaust gas passage resistance is low and the exhaust gas flow is not impaired, the performance of the turbocharger 5 does not deteriorate. Further, for example, when a generally used cylindrical honeycomb catalyst or metal catalyst is provided in the exhaust pipe, the airflow resistance is large, the exhaust performance is reduced, and the engine output (turbo speed) may be reduced. On the other hand, in the present embodiment, as described above, the catalyst layer 33 is provided on both the inner wall surface 31a and the outer wall surface 31b of the cylindrical portion 31 and the airflow resistance is small, so that the catalyst layer 33 is provided upstream of the turbocharger 5. Even if 33 is provided, the performance (turbo rotation speed) of the turbocharger 5 will not be reduced, and the output of the engine 1 can be maintained at a good value.

Further, since the catalyst layer 33 is provided in the cylindrical portion 31 inserted into the branch pipe 23 of the exhaust manifold 2, it is not necessary to secure a particularly large space for providing the catalyst layer 33. And the versatility can be improved. Further, since it is not necessary to secure a particularly large space for providing the catalyst layer 33 as described above, even when the turbocharger 5 is used as shown in the present embodiment, the arrangement of the catalyst layer 33 is easy. Can be done. That is, in the above-described engine 1 with the turbocharger 5 shown in FIG. 9, it is difficult to dispose the catalyst (catalytic converter 4) in the engine room because the turbocharger 5 is arranged in the engine room. However, in the present embodiment, on the other hand, even if the turbocharger 5 is used, the catalyst layer 33 can be easily arranged.

A plurality of holes (tube holes 34) may be formed in the tube portion 31 as shown in FIG.
Second Embodiment). In the second embodiment, the exhaust gas flows through the cylindrical hole 34 and the exhaust gas reaches both sides of the cylindrical portion 31. For this reason, the exhaust gas is
Purification is efficiently performed by the catalyst layer 33 on the outer wall surface 31b and on the outer wall 31a, and the purification performance can be improved.

In the above-described embodiment, the case where the cylindrical portion 31 has a cylindrical shape is taken as an example. However, instead of this, for example, a rectangular cylindrical cylindrical portion may be adapted to the shape of the exhaust manifold 2 as shown in FIG. 31A may be used.

[0014]

According to the first aspect of the present invention, the gasket is provided with a tubular portion to be inserted into the passage of the exhaust manifold, and the tubular portion is provided with a catalyst layer. When passing through the section, it is purified by the catalytic action of the catalyst layer. The exhaust gas coming into contact with the catalyst layer is directly discharged from the internal combustion engine and has a high exhaust temperature, so that the catalyst function is activated earlier and the purification performance is improved accordingly. Exhaust gas purification is performed by providing a catalyst layer in the cylindrical portion, and since the ventilation resistance is low and the exhaust gas flow is not impaired, even if the catalyst layer is provided on the upstream side of the turbocharger, the performance of the turbocharger ( Turbo speed)
Therefore, the output of the engine can be maintained at a good value without lowering the engine speed. Further, since the catalyst layer is provided in the cylindrical portion inserted into the passage of the exhaust manifold, it is not necessary to secure a specially large space for providing the catalyst layer, and there is little restriction on the space. Further, as described above, since it is not necessary to secure a specially large space for providing the catalyst layer, the catalyst layer can be easily arranged even when a turbocharger is used. Further, the catalyst layers are provided on both the inner wall surface and the outer wall surface of the cylindrical portion, and the contact area with the exhaust gas is increased. Therefore, it is possible to increase the purification amount of the exhaust gas.

According to the second aspect of the present invention, since a gap is formed between the wall surface of the passage and the cylindrical portion, and the catalyst layer is formed on both surfaces of the cylindrical portion, the contact area with the exhaust gas increases. The amount of purification of exhaust gas can be increased. According to the third aspect of the invention, a gap is formed between the wall surface of the passage and the cylindrical portion, the catalyst layer is formed on both surfaces of the cylindrical portion, a plurality of holes are formed in the cylindrical portion, and exhaust is performed through the holes. Since the gas flows and the exhaust gas spreads on both sides of the cylindrical portion, the exhaust gas is efficiently purified by the catalyst layers on the inner wall surface and the outer wall surface, and the purification performance can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view schematically illustrating an exhaust gas purification device according to a first embodiment of the present invention.

FIG. 2 is a view schematically showing a flange and a branch pipe of the gasket and the exhaust manifold of FIG. 1;

FIG. 3 is a plan view showing the gasket of FIG. 1;

FIG. 4 is a side view showing the gasket of FIG. 3;

FIG. 5 is a cylindrical portion having a hole formed therein (second embodiment of the present invention).
FIG.

FIG. 6 is a plan view showing a tubular portion having a rectangular tubular shape.

FIG. 7 is a diagram schematically illustrating an example of a conventional exhaust gas purification apparatus (an example using an underfloor catalyst).

FIG. 8 is a diagram schematically showing another example (an example using a warm-up catalyst) of a conventional exhaust gas purification apparatus.

FIG. 9 is a diagram schematically showing an example of a conventional exhaust gas purification device used for an engine using a turbocharger.

[Description of Signs] 1 Engine 2 Exhaust manifold 22 Gasket 31 Tube part 33 Catalyst layer

Claims (3)

[Claims] 1. A gasket interposed between an internal combustion engine and an exhaust manifold connected to the internal combustion engine is provided with a cylinder inserted into a passage of the exhaust manifold, and a catalyst layer is provided on the cylinder. An exhaust gas purification device characterized by the following. 2. The exhaust gas purifying apparatus according to claim 1, wherein a gap is formed between a wall surface of the passage and the cylindrical portion, and the catalyst layers are formed on both surfaces of the cylindrical portion. 3. The exhaust gas purifying apparatus according to claim 2, wherein a plurality of holes are formed in the cylindrical portion.