JP3321763B2 - Engine exhaust gas treatment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an engine exhaust gas treatment device having a function of purifying engine exhaust gas and a function of silencing the engine exhaust gas.

[0002]

2. Description of the Related Art Exhaust gas generated when fuel such as gasoline or light oil explodes and burns in an engine is harmful to carbon monoxide (CO), hydrocarbon (HC), nitrogen oxide (NOx), carbon dioxide (CO2). CO ₂ ) and harmless steam (H
_Two- way catalyst converters such as ceramic honeycombs and metal honeycombs are known as an example of a method for purifying harmful gases. Further, the explosion sound of the fuel is silenced by a muffler arranged on the rear side of the catalyst device.

The current three-way catalyst converter uses Pt (platinum) + Rh (rhodium) as a catalyst, oxidizes CO and HC contained in exhaust gas, and reduces NOx to thereby simultaneously convert three components. Has been reduced. However, in the case of a gasoline engine, even if the air-fuel mixture is controlled to the theoretical air-fuel ratio, sudden acceleration occurs when the engine starts. There is a problem that the three-way catalyst becomes overworked during high-speed running and cannot exert a sufficient purification function. In the case of diesel engines, carbon mist and particulate matter contained in exhaust gas There is a problem that a large amount of (particulate) adheres and the catalytic function does not work at all.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention has been proposed for the purpose of effectively removing harmful components of engine exhaust gas and effectively silencing a fuel explosion sound. It is.

[0005]

A first means adopted by the present invention to solve the above problems is a catalyst device for purifying exhaust gas of an engine through a catalyst substance, a silencer,
A radiating device for lowering the temperature of the exhaust gas to a predetermined temperature, and an exhaust gas neutralizing device for neutralizing an oxidizing component in the exhaust gas, wherein the catalyst device forms a flow path for spirally moving the exhaust gas, The exhaust gas contact surface of the gas flow path is coated with a heat-resistant hollow material, and a filter material having a catalytic substance attached to the surface of the heat-resistant hollow material is disposed. A ceramic in which an alkaline substance is mixed is disposed in the exhaust gas flow path. According to a second aspect of the present invention, in the catalyst device, a screw fin is disposed inside a casing, and the screw fin and the inner wall surface of the cylinder are coated with a heat-resistant hollow material.
It is characterized in that a filter material having a catalytic substance adhered thereto is adhered to the surface of a baking material, and a device for burning a removing substance is provided on the bottom of the casing. A third means of the present invention is characterized in that the muffler has a heat-resistant hollow material coated on an inner surface through which exhaust gas passes. A fourth means of the present invention is characterized in that the exhaust gas neutralizing device is constructed by inserting an alkaline ceramics sleeve into a cylindrical casing. A fifth means of the present invention is characterized in that the alkaline ceramics sleeve is constituted by a cement-made slate pipe. A sixth means of the present invention is characterized in that the alkaline ceramics sleeve is constituted by a pipe made of cement mortar. A seventh means of the present invention is characterized in that the catalyst device is a primary catalyst device, and a secondary catalyst device is arranged between the primary catalyst device and the muffler. According to an eighth aspect of the present invention, there is provided the secondary catalyst device, wherein the three-way catalyst comprises a heat-resistant hollow layer formed on the surface of the honeycomb structure, and a three-way catalyst substance adhered to the surface of the hollow layer. The device is characterized in that: The ninth means of the present invention is:
The heat-resistant hollow is a self-purifying catalyst hollow.

[0006]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall configuration diagram of an engine exhaust gas treatment apparatus according to the present invention. Exhaust gas generated by explosive combustion of fuel in a cylinder chamber of an engine 1 passes through an exhaust manifold hold 2. , The primary catalyst converter-3, the secondary catalyst converter-4, the muffler 5, the radiator tube 6, the regulator / muffler 7 and the tail pipe 8 are discharged to the outside air.

[0007] The primary catalyst converter-3 is designed so that the secondary catalyst converter-4 functions effectively.
It is arranged in front of the tab-4. Primary catalyst converter
3 is a casing 10, as shown in FIGS.
It has a screw fin 14 inserted therein, an exhaust gas inlet 11 is opened on the manifold side of the casing 10, and a secondary catalyst converter is provided on the other end.
An exhaust gas outlet 12 connected to the exhaust gas outlet 4 is provided.
The casing 10 has a cylindrical shape as a whole, and upper and lower half portions are fixed at the flange portion 13.

[0008] Inside the casing 10, a flow path is formed by the screw fins 14 so that the exhaust gas passes through the meandering spiral. The surface of the screw fins 14 and the inner wall surface of the casing 10 are provided with a heat-resistant self-cleaning (SC) hollow, which will be described later, and the entire hollow surface is a very fine filter. -15 is attached.

The filter 15 is made of, for example, a thin wire made of stainless steel (for example, in the case of a plate shape, a thickness of 0.02 mm
０．２0.2 mm, width of about 0.5 mm to 5.0 mm, and in the case of a round bar, use a filter having a diameter of 20 μm to 1.0 mm). Catalyst material particles such as manganese and nickel oxide are applied and baked.

A plurality of glow plugs 16 are provided at the bottom of the casing in the longitudinal direction, and the removed substances (carbon mist, putty) collected at the bottom in the casing 13 are provided.
(E.g., particulate matter such as ureate) .

The above-described S.D. C enamel is a self-purifying catalytic enamel, which basically consists of a catalyst, a heat-resistant binder (frit), and a mat-forming agent (porous forming agent). Has a function of adsorbing and decomposing and purifying by catalytic action. As the catalyst, a highly active catalyst such as γ-MnO ₂ or Zn—Mn ferrite for oxidation and α-Al ₂ O ₃ or zeolite (aluminosilicate) for decomposition is used. Used in powder form. As the frit, borosilicate glass is used in this embodiment.

S. As the metal substrate of C hollow, a cold-rolled steel plate, an aluminized steel plate or the like is used, and an undercoating hollow layer as a corrosion-resistant layer is formed on the metal substrate.
S. The C hollow layer is formed with a predetermined thickness on the upper surface of the undercoating hollow layer. S. C-hollow is porous and has a larger specific surface area than before (5.0).
m ² /g~7.0m ² / g). As a result, the area of contact with fats and oils and particulate matter is enlarged, and these are instantaneously diffused into the catalyst layer, and the reaction products are smoothly dissipated during the catalytic reaction.

The secondary catalyst converter 4 is a three-way catalyst converter, and purifies three components of CO, HC and NOx in the exhaust gas by oxidation and reduction. In the present invention, as shown in FIG. 6, a metal honeycomb 32 made of stainless steel or steel plate is mounted inside a casing 30 with a heat insulating material 33 interposed therebetween. On the surface of the metal honeycomb 32, a heat-resistant ceramic coating or the above-described heat-resistant S.A. C-hollow is fired, and a Pt + Rh three-way catalyst is attached to the surface of the fired layer. An exhaust gas temperature sensor 31 is provided near the exhaust port of the three-way catalyst converter 4 to detect abnormally high temperature when a high concentration of CO, HC, etc. flows in and a large load is applied to the catalyst. Detected.

The above-mentioned metal honeycomb 32 has a structure in which the distance between the flow paths is narrow (a cross-sectional area is 20 mm ^{2 to} 500 mm).
mm ^2, the total cross-sectional area of 50mm ² ~1500mm ² about), refractory ceramic co - coating or heat S. The fired layer of C hollow is finished in a porous state. Therefore,
The exhaust gas passing through the metal honeycomb 32 surely comes into contact with the surface of the fired layer of the metal honeycomb 32, and the purification and purification of the exhaust gas is promoted by Pt + Rh.

The three-way catalyst has an excellent purifying capability for NOx when burned in a state richer than the stoichiometric air-fuel ratio, and has an excellent purifying ability for CO and HC in a thin state. The sensor detects the amount of oxygen in the exhaust gas and the microcomputer controls the mixture to near the stoichiometric air-fuel ratio.

In such a three-way catalyst converter-4, an inexpensive stainless steel plate (S
AS430, 410, 409 etc.) or a thin steel plate, and the surface thereof is coated with ceramic coating or S.A. C-ho
Since it is manufactured by firing b, it can be manufactured at lower cost than conventional expensive heat-resistant stainless steel or ceramic honeycomb products, and has excellent durability and the like.

The above-described muffler 5 is a muffler having a conventionally known structure, but in the present invention, the above-described S.M. C-hollow has been fired. This S. Purification of exhaust gas is promoted by the C-hollow, and a further adsorption effect can be obtained due to the special porous surface condition. That is, this porous material serves as a catalytic reaction layer for oils and fats, HC, CO
Instantaneously diffuses into the catalyst layer, while supplying oxygen and CO
Dissipation of the reaction product such as ₂ can be performed smoothly. Also, this porous surface absorbs explosive combustion noise,
It has the effect of silencing due to diffuse reflection.

As shown in FIGS. 7 and 8, the heat radiating tube 6 has a large number of heat radiating fins 17 formed on the outer peripheral surface of a cylindrical body, and an exhaust gas inlet 18 is opened at the end of the muffler side. An exhaust gas outlet 19 is opened at the other end.
The radiation tube 6 of this embodiment is formed by bending the radiation fin 1.
7 integrally formed with four blocks 20a, 20b, 20
c and 20d (see FIG. 8) are united to form a tubular shape, and a tube serving as an exhaust gas inlet 18 and an outlet 19 is joined to both ends thereof.

On the inner and outer surfaces of the radiator tube 6, the above-mentioned S.P. C-hollow is fired, or metal spraying of metal such as stainless steel and aluminum (metallicone = metal gas spraying) is performed to improve the absorption of high-temperature exhaust gas and the radiation cooling effect of the conduction heat. ing. In addition, since the metal-sprayed surface is porous, the sound of the exhaust explosion is absorbed and diffusely reflected on the wall surface, so that a further noise reduction effect is achieved.

The regulator / muffler 7, which is an exhaust gas neutralizing device, has a structure in which an alkaline ceramics sleeve 22 is disposed inside a cylindrical casing 21 as shown in FIGS. ing. The alkaline ceramics sleeve 22 is held by a support 23 provided on the inner surface of the casing 21.

The alkaline ceramics sleeve 22 is a cement-made slate pipe or a cement mortar pipe. An alkaline substance such as caustic soda, polymerized phosphate, and sodium nitrate is added to a cement raw material at a component ratio of 5%. % To 100%, and molded into a pipe. A large number of holes (φ1.0 mm to φ10 mm) are formed on the surface to promote ventilation and circulation.

Cement mortar concrete is known to absorb CO ₂ well (when a lm ² mass completely reacts, it absorbs about 70 g of CO ₂ ), and the ceramic sleeve 22 is molded. Occasionally, it is molded to be porous, and a large number of pores (1.0 mmφ to 8.0 mmφ) are formed on the front surface of the sleeve to improve air permeability. In addition, regular
An exhaust gas inlet 2 is provided at the end of the radiator tube side of the
4 is opened, and an outlet 25 is also opened at the other end.

Next, the operation of each component of the above-described exhaust gas treatment apparatus will be described. Exhaust gas discharged from the engine 1 is guided to a primary catalyst converter 3 through a manifold 2. In the primary catalyst converter 3, the exhaust gas passes while spirally meandering along the screw fins 14, and comes into contact with the screw fins 14 and the filter 15 attached to the inner wall surface of the casing. In the present invention, since the exhaust gas flows along the screw fins 14 having a large area, the contact area with the filter 15 is increased.

When the exhaust gas comes into contact with the filter 15, particulate matter such as carbon mist and particulates contained in the exhaust gas is captured, and the catalyst material calcined by the filter 15 is removed. CO, H in contact
Most of C and NOx change to CO ₂ , H ₂ O and the like. The surface of the screw fin 14 and the inner wall surface of the casing are S. Since C-hollow is applied, fats and oils and fine particles in the exhaust gas are well adsorbed on these surfaces and decomposed and purified by the catalyst.

S. Substances that do not adhere to the surface of the C-hollow fall and collect at the bottom of the casing 10 and are incinerated by the glow plug 16. The glow plug 16 is ignited in a predetermined cycle. The exhaust gas is the primary catalyst converter.
During the meandering passage through the inside of S.3, the pressure was reduced. C-ho
The explosion sound is reduced in combination with the low sound absorption effect.

In the secondary catalyst converter-4, the exhaust gas purified by the primary catalyst converter-3 is further purified by the above-mentioned three-way catalyst system to remove CO, HC, NOx and the like. In the secondary catalyst converter-4, carbon mist and particulate matter are trapped by the primary catalyst converter-3 in the foreground, so that the three-way catalyst function can be effectively exhibited. become.

The exhaust gas that has entered the muffler 5 from the secondary catalyst converter 4 is silenced here, but in the case of the present invention, the S.F. C hollow
The special porous surface condition promotes a further sound absorbing effect, while An effect of accelerating purification of exhaust gas by C-hollow is obtained.

The exhaust gas in the muffler 5 has a high temperature (about 800
° C) and a regulator / muffler described later.
The exhaust gas temperature in the heat radiating pipe 6 is sufficiently lowered in order for the 7 to function sufficiently. In this embodiment, the temperature is lowered so that the exhaust gas temperature at the outlet 25 is about 150 ° C. to 200 ° C. The heat radiating tube 6 is a hollow heat radiating fin 1.
7, the internal volume of the entire heat radiating tube is increased, and accordingly, the decompression and silencing effect is promoted.

In the regulator / muffler 7, the exhaust gas whose temperature has been lowered by the radiating tube 6 is brought into contact with the alkali ceramics rib 22 to neutralize the oxidized component. That is, the exhaust gas purified by the primary catalyst converter 3 and the secondary catalyst converter 4 almost contains oxidizing substances such as CO ₂ and NOx, and this is converted into an alkaline ceramics rib 2.
Neutralize with 2.

The exhaust gas contains a considerable amount of water vapor (H ₂ O)
Is cooled by the heat radiating tube 6 and becomes liquid to give moisture to the alkali ceramics slab 22,
The alkaline component impregnated in the sleeve 22 gradually wets and comes into contact with the exhaust gas to neutralize and absorb CO ₂ , NOx and the like. Especially in diesel engines, NOx in exhaust gas
Because of the large amount, it is desirable to increase the length of the alkaline ceramics sleeve 22 and purify by increasing the surface area as necessary.

Since the alkaline ceramics sleeve 22 is porous and has many pores formed in its entirety, the explosion sound of the exhaust gas is such that sound waves are irregularly reflected when passing through the sleeve. The sleeve 22 is long and almost completely silenced. When the alkaline ceramics sleeve 22 is neutralized and becomes saturated,
The sleeve 22 is taken out of the casing 21, washed and dried, immersed again in an alkaline solution to absorb the alkali component, and mounted on the casing 21 for recycling.

The above embodiment is an example of the present invention. For example, when a sufficient purifying effect can be obtained only by the primary catalyst converter 3, the secondary catalyst converter 4 can be omitted. . Further, the secondary catalyst converter-4 is not limited to the three-way catalyst type, but may be a conventionally known oxidation catalyst device or a purification device of another processing type. In addition, the configuration of each of the illustrated components is merely an example, and can be changed as needed in an actual design.

[0033]

According to the present invention described above, the harmful components of the engine exhaust gas can be effectively removed, and an excellent noise reduction effect of the fuel explosion sound can be obtained.

[Brief description of the drawings]

FIG. 1 is an overall schematic configuration diagram showing an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view of a primary catalyst converter used in the present embodiment.

FIG. 3 is an axial sectional view of the primary catalyst converter shown in FIG. 2;

FIG. 4 is a sectional view taken along a line AA in FIG. 3;

FIG. 5 is a sectional view taken along a line BB in FIG. 3;

FIG. 6 is a partially cutaway perspective view of a three-way catalyst converter used in the present embodiment.

FIG. 7 is a partially cutaway perspective view of a radiator tube used in the present embodiment.

FIG. 8 is a radial cross-sectional view of the radiator tube shown in FIG.

FIG. 9 shows a regulator and muffler used in the present embodiment.
3 is a partially cutaway sectional view of FIG.

FIG. 10 is an axial sectional view of the regulator / muffler shown in FIG. 8;

[Description of sign]

 DESCRIPTION OF SYMBOLS 1 Engine 2 Manifold 3 Primary catalyst converter 4 Secondary catalyst converter 5 Muffler 6 Radiator tube 7 Regulator and muffler 14 Screw fin 15 Filter 16 Glow plug 17 Radiation fin 22 Alkaline ceramics leave

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI F01N 3/02 311 F01N 3/02 ZABZ ZAB B01D 53/36 ZABB (58) Fields surveyed (Int.Cl. ⁷ , DB name) F01N 3/24 B01D 53/86 F01N 3/02

Claims (9)

(57) [Claims] 1. A catalyst device for purifying exhaust gas of an engine via a catalytic substance, a silencer, a heat radiating device for lowering the temperature of exhaust gas to a predetermined temperature, and an exhaust gas for neutralizing an oxidizing component in the exhaust gas. The catalyst device comprises a flow path for spirally moving the exhaust gas, and a heat-resistant hose is provided on the exhaust gas contact surface of the exhaust gas flow path.
A filter material coated with a catalytic material on the surface of the heat-resistant hollow material, and wherein the exhaust gas neutralizing device comprises a ceramic in which an alkaline substance is mixed in the exhaust gas flow path. An exhaust gas treatment device for an engine, wherein: 2. The catalyst device according to claim 1, wherein a screw fin is disposed inside the casing, and the screw fin and the inner wall surface of the cylinder are covered with a heat-resistant hollow material.
Placing a filter material with a catalytic substance on the surface of the material,
2. The exhaust gas treatment device for an engine according to claim 1, wherein a combustion device for removing substances is provided at the bottom of the casing. 3. The muffler according to claim 1, wherein an inner surface through which the exhaust gas passes is coated with a heat-resistant hollow material.
An engine exhaust gas treatment apparatus according to claim 2 or 3. 4. The exhaust gas neutralizing device according to claim 1, wherein an alkaline ceramics sleeve is inserted into a cylindrical casing. An exhaust gas treatment device for the engine as described in the above. 5. The exhaust gas treatment device for an engine according to claim 4, wherein said alkaline ceramics sleeve is constituted by a cement-made slate pipe. 6. The exhaust gas treatment device for an engine according to claim 4, wherein said alkaline ceramics sleeve is constituted by a pipe made of cement mortar. 7. The exhaust system according to claim 1, wherein the catalyst device is a primary catalyst device, and a secondary catalyst device is disposed between the primary catalyst device and the muffler. Gas treatment equipment. 8. The secondary catalyst device is a three-way catalyst device in which a heat-resistant hollow layer is formed on the surface of a metal honeycomb structure, and a three-way catalyst substance is adhered to the surface of the hollow layer. The exhaust gas treatment device for an engine according to claim 7, wherein: 9. The exhaust gas of an engine according to claim 1, wherein the heat-resistant hollow is a self-purifying catalyst hollow. Processing equipment.