JP3468096B2 - Catalytic converter device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic converter device and, more particularly, to a technique for enhancing HC purification performance.

[0002]

2. Description of the Related Art Conventionally, as a catalytic converter device, there is one disclosed in JP-A-7-332073. In this catalytic converter device, a three-way catalyst is arranged close to a HC adsorbent having a function of adsorbing HC in exhaust gas at a low temperature with a predetermined interval.

That is, by arranging a three-way catalyst on the downstream side of the HC adsorbent at a predetermined interval, HC in the exhaust gas is adsorbed to the HC adsorbent during cold conditions, and after warm-up is completed. The HC is desorbed from the HC adsorbent, and the desorbed HC can be purified by a three-way catalyst disposed in the exhaust gas downstream portion of the HC adsorbent, and at the same time, it can be separated from the HC adsorbent under high temperature conditions. Prevent reaction with the original catalyst,
Improves heat resistance of HC adsorbent and three-way catalyst.

Alternatively, by arranging three-way catalysts having different components respectively on the downstream side and the upstream side of the HC adsorbent, in addition to the effect of the above-mentioned constitution, all HC species (olefin group carbonization Hydrogen, paraffin hydrocarbons, aromatic hydrocarbons) can be purified.

[0005]

However, as described above, in the catalytic converter device in which the three-way catalyst is arranged close to the HC adsorbent at a predetermined interval, the following is performed. There is a problem. That is, the HC adsorbent requires a predetermined capacity in terms of its adsorption capacity, but if it has a large capacity, its heat capacity (heat mass) increases, and the exhaust gas temperature at the inlet of the three-way catalyst located downstream thereof decreases. However, the three-way catalyst cannot reach the activation temperature quickly.

Therefore, when desorption of HC from the HC adsorbent starts, if the downstream three-way catalyst is not sufficiently activated, the HC desorbed from the HC adsorbent is released without being converted. Therefore, it is impossible to suppress the discharge of HC during cold. Therefore, in view of the conventional problems as described above, the present invention improves the arrangement structure of the HC adsorbent and the three-way catalyst while sufficiently securing the adsorbing ability of the HC adsorbent and converting the HC by the three-way catalyst. It is an object of the present invention to provide an exhaust gas purification device that can improve the performance and effectively suppress the emission of HC during cold weather.

[0007]

Therefore, in the invention according to claim 1, two or more HC adsorbents and two or more three-way catalysts are arranged such that the three-way catalyst is located downstream of the HC adsorbents. In the catalytic converter device arranged alternately and in series with each other, the HC adsorbent has a capacity having at least a predetermined adsorption capacity as a whole, and the three-way catalyst has a capacity having at least a predetermined three-way capacity as a whole. , and the and, HC adsorbent is a same number as the three-way catalyst, co mutually
It is characterized in that they are arranged while maintaining a predetermined interval by nulling . The invention according to claim 2 has two or more HC adsorptions.
Material and two or more three-way catalysts
The catalyst components are arranged alternately and in series so that the medium is located.
In the burner device, the amount of HC adsorbent is small as a whole.
Even if it has a capacity with a specified adsorption capacity,
The three-way catalyst as a whole has at least a predetermined three-way capability.
It has the capacity and the HC adsorbent is the same number as the three-way catalyst.
And the spacers are arranged while maintaining a predetermined distance with each other.
It is characterized by being placed .

The invention according to claim 3 is an HC adsorbent and a ternary
Each of the catalyst carriers has a relationship that the heat capacity thereof gradually increases from the upstream side to the downstream side of the exhaust passage, and the carrier of the HC adsorbent and the carrier of the three-way catalyst adjacent to the carrier of the HC adsorbent are
The heat capacity of the carrier of the C adsorbent is large, and the heat capacity of the carrier of the three-way catalyst is smaller than that of the HC adsorbent.

The invention according to claim 4 is a catalyst in which two or more HC adsorbents and two or more three-way catalysts are alternately and serially arranged so that the three-way catalyst is located downstream of the HC adsorbents. In the converter device, each carrier of the HC adsorbent and the three-way catalyst has a relationship in which the heat capacities gradually increase from the upstream side to the downstream side of the exhaust passage, and are adjacent to the HC adsorbent carrier on the downstream side thereof. The carrier of the three-way catalyst is characterized in that the carrier of the HC adsorbent has a large heat capacity, and the carrier of the three-way catalyst has a heat capacity smaller than that of the HC adsorbent.

According to a fifth aspect of the present invention, the width of each carrier of the HC adsorbent and the three-way catalyst is gradually increased from the upstream side to the downstream side of the exhaust passage, and the carrier of the HC adsorbent is formed. And the widths of the three-way catalyst carriers adjacent to each other in the downstream are such that the width of the carrier of the HC adsorbent is large and the width of the carrier of the three-way catalyst is smaller than the width of the carrier of the HC adsorbent. It is characterized in that it is formed and set in the relation of the heat capacity.

In the sixth aspect of the invention, the carrier of the HC adsorbent and the carrier of the three-way catalyst are set so that the number of cells of the carrier of the HC adsorbent is smaller than the number of cells of the carrier of the three-way catalyst. Is characterized by. The invention according to claim 7 is characterized in that the wall of each cell of the carrier of the three-way catalyst is formed thin. Contract
The invention according to claim 8 is set such that the carrier of the HC adsorbent and the carrier of the three-way catalyst have a smaller amount of precious metal carried on the carrier of the HC adsorbent than the amount of precious metal carried on the carrier of the three-way catalyst. It is characterized by having done. The invention according to claim 9 is characterized in that a three-way catalyst is arranged in series at a predetermined interval further upstream of the HC adsorbent at the most upstream position.

The operation of the present invention will be described. Contract
In the invention according to claim 1 or 2 , two or more HC adsorbents and two or more three-way catalysts are predetermined by cornering or spacers so that the three-way catalysts are located downstream of the HC adsorbents.
By alternately and serially arranging while maintaining the interval, it is possible to set each HC adsorbent and each three-way catalyst to an optimum temperature rising characteristic.

By setting the capacities of the respective HC adsorbents and the respective three-way catalysts, it is possible to secure the required capacity as a whole, and to secure the required adsorption capacity and three-way capacity, and to use the HC adsorbent having a small heat mass. Can be placed in front of the three-way catalyst
It becomes possible and is installed between the HC adsorbent and the three-way catalyst.
Depending on the specified interval, the reaction heat of the three-way catalyst
It becomes difficult for the three-way catalyst to reach the activation temperature, and the three-way catalyst can quickly reach the activation temperature.

For this reason, when the desorption of HC from the HC adsorbent begins, the three-way catalyst downstream thereof is sufficiently activated, so that the HC desorbed from the HC adsorbent is released without being converted. It is possible to prevent HC from being discharged, and it is possible to suppress discharge of HC during cold. In the invention according to claim 3 , each H
Since the C adsorbent and each of the three-way catalysts have a relationship in which the heat capacities gradually increase from the upstream side to the downstream side of the exhaust passage, the HC adsorbent is positioned from the upstream side to the downstream side. The HC desorption temperature is reached in sequence, and the three-way catalyst
The HC purification start temperature is reached in the order from those located on the upstream side to those located on the downstream side. Further, in the adjoining HC adsorbent and the three-way catalyst, when the HC adsorbent reaches the HC desorption temperature, the three-way catalyst also reaches the HC purification start temperature.

Therefore, when the desorption of HC from the HC adsorbent starts, the three-way catalyst downstream thereof is surely activated, and the HC desorbed from the HC adsorbent is surely converted by the three-way catalyst. To be done. In the invention according to claim 4 , two or more HC adsorbents and two or more three-way catalysts are arranged alternately and in series so that the three-way catalysts are located downstream of the HC adsorbents. It is possible to set the HC adsorbent and each of the three-way catalysts to individual optimum temperature rising characteristics. Since the HC adsorbents and the three-way catalysts have a relationship in which the heat capacities gradually increase from the upstream side to the downstream side of the exhaust passage, the HC adsorbents move from the upstream side to the downstream side. The HC desorption temperature is reached in the order of those located, and the three-way catalyst
The HC purification start temperature is reached in the order from those located on the upstream side to those located on the downstream side. Further, in the adjoining HC adsorbent and the three-way catalyst, when the HC adsorbent reaches the HC desorption temperature, the three-way catalyst also reaches the HC purification start temperature. Therefore, when desorption of HC from the HC adsorbent starts, the three-way catalyst downstream thereof is surely activated, and HC desorbed from the HC adsorbent is surely converted by the three-way catalyst. Contract
In the invention according to claim 5 , the widths of the respective carriers of the HC adsorbent and the three-way catalyst are gradually increased from the upstream side to the downstream side of the exhaust passage, and the carrier of the HC adsorbent and its downstream side are formed. The widths of the adjacent three-way catalyst carriers are formed such that the width of the HC-adsorbent carrier is large and the width of the three-way catalyst carrier is smaller than the HC-adsorbent carrier width. By
The heat capacity relationship according to claim 3 or claim 4 is set. In the invention according to claim 6 , when the number of cells of the carrier of the HC adsorbent is reduced, the coating amount of the adsorbing component such as zeolite is the same, and the coating layer of the adsorbing component in each cell is larger than when the number of cells is large. As the thickness increases, the desorption characteristics of the adsorbed HC become difficult to desorb, that is, the desorption rate of HC becomes slower.

In the invention according to claim 7 , as a result of forming the wall of each cell of the carrier of the three-way catalyst thin, the temperature rising property of the carrier of the three-way catalyst becomes better and the activation becomes faster.
In the invention according to claim 8 , by reducing the amount of the noble metal supported on the carrier of the HC adsorbent as compared with the carrier of the three-way catalyst, heat generation of the coating layer of the adsorbed component is reduced,
The desorption characteristics of the adsorbed HC become difficult to desorb, that is, the HC desorption temperature becomes slower to reach.

Further, by increasing the amount of the noble metal supported on the carrier of the three-way catalyst, the temperature rising property of the carrier is improved, the activation is accelerated, the HC purification start temperature is reached faster, and the purification performance is improved. Be improved. As in the invention according to claims 6 to 8 , the number of cells of the carrier of the HC adsorbent and the three-way catalyst, HC
Depending on the amount of noble metal supported on the adsorbent and the three-way catalyst carrier and the wall thickness of the cell of the three-way catalyst carrier,
When the desorption of the three-way catalyst starts, the three-way catalyst downstream of the three-way catalyst can be surely activated, and the effect that the HC desorbed from the HC adsorbent can be surely converted by the three-way catalyst can be exhibited more reliably. it can.

In the invention according to claim 9 , the three-way catalyst is arranged in series at a predetermined interval further upstream of the HC adsorbent at the most upstream position, so that the HC in the exhaust gas at the time of cold start is reduced to HC. It can be converted by a three-way catalyst before being adsorbed by the adsorbent, and the HC purification performance can be improved.

[0019]

According to the inventions according to claims 1 and 2 , it is possible to set each HC adsorbent and each three-way catalyst to an optimum temperature rising characteristic, and to remove HC from the HC adsorbent. When the separation starts, the emission of HC during cold can be suppressed by setting the temperature rising characteristics such that the activation of the downstream three-way catalyst is sufficient.

Also, by securing the necessary capacity as a whole,
While it is possible to secure the required adsorption capacity and three-way capacity, it is possible to position the HC adsorbent with a small heat mass in the preceding stage of the three-way catalyst, so that the three-way catalyst can reach the activation temperature quickly and cool It is possible to suppress the discharge of HC during the time.
According to the invention of claim 3 , when the desorption of HC from the HC adsorbent is started, the three-way catalyst downstream thereof is surely activated, and the HC desorbed from the HC adsorbent is the three-way catalyst. Therefore, it is possible to reliably convert HC, and to more reliably suppress the discharge of HC during cold.

According to the fourth aspect of the present invention, it becomes possible to set each HC adsorbent and each three-way catalyst to the optimum temperature rising characteristics, and the desorption of HC from the HC adsorbent has started. Occasionally, by setting the temperature raising characteristics such that the downstream three-way catalyst is sufficiently activated, it is possible to suppress the emission of HC during cold. Then, when desorption of HC from the HC adsorbent begins, the three-way catalyst downstream thereof is surely activated,
The HC desorbed from the adsorbent can be reliably converted by the three-way catalyst. According to the invention of claim 5 , claim 3
Alternatively, the heat capacity relationship according to claim 4 can be set. According to the inventions according to claims 6 to 8 , the number of cells of the carrier of the HC adsorbent and the three-way catalyst, the amount of noble metal supported on the carrier of the HC adsorbent and the three-way catalyst, and the wall thickness of the cell of the carrier of the three-way catalyst. By setting the above, the effect that the HC desorbed from the HC adsorbent can be surely converted by the three-way catalyst can be exhibited more reliably, and the discharge of HC during cold can be suppressed more reliably.

According to the invention of claim 9 , at the time of cold start, HC in the exhaust gas can be converted by the three-way catalyst before being adsorbed by the HC adsorbent, and the HC purification performance can be further improved. it can.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a schematic sectional view showing an embodiment of a catalytic converter device according to the present invention. In this figure, a catalytic converter device 1 includes two or more HC adsorbents and two or more HC adsorbents in a shell 2 interposed in an exhaust passage of an internal combustion engine.
Three or more three-way catalysts with the same number as the HC adsorbent,
The three-way catalysts are arranged alternately and in series so that the three-way catalyst is located downstream of the adsorbent.

In the present embodiment, three HC adsorbents A ₁ , A ₂ , A ₃ and three three-way catalysts B ₁ , B ₂ , B ₃ are provided, and the upstream side of the exhaust passage (the left side in the figure). ) To the downstream side (right side of the figure), A ₁ , B ₁ , A ₂ , B ₂ , A ₃ , B ₃
Are arranged in this order. When a ceramic carrier is used as a carrier for each of the HC adsorbents A ₁ , A ₂ , A ₃ and each of the three-way catalysts B ₁ , B ₂ , B ₃ , each ceramic carrier 3 is provided in the shell 2.
Are housed at a predetermined interval L, and each ceramic carrier 3
The outer peripheral portion of the end of the shell is held by the corner ring 4 on the inner peripheral portion of the shell 2 (see FIG. 2).

Further, in the case where the metal carrier 5 is used as a carrier for each of the HC adsorbents A ₁ , A ₂ , A ₃ and each of the three-way catalysts B ₁ , B ₂ , B ₃ , in the shell 2, each metal carrier 5 is used. Then, a predetermined space L between the metal carriers 5 is held by the spacers 6, and the outer peripheral surface of each metal carrier 5 is directly attached to the inner peripheral surface of the shell 2 by brazing or the like (see FIG. 3). Here, the HC adsorbents A ₁ , A ₂ , and A ₃ are set to have the capacities of the HC adsorbents having a predetermined adsorption capacity divided into three, and the three-way catalysts B ₁ , B ₂ , and B ₃ are , The capacity of a three-way catalyst having a predetermined three-way capacity is set to a capacity divided into three.

Further, all the HC adsorbents A ₁ , A ₂ , A ₃
Each of the three-way catalysts B ₁ , B ₂ , and B ₃ (ceramic carrier, metal carrier) has a relationship that the heat capacities gradually increase from the upstream side to the downstream side of the exhaust passage, and the adjacent HCs are adjacent to each other. The carrier of the adsorbent and the carrier of the three-way catalyst have a large heat capacity of the carrier of the HC adsorbent, and the heat capacity of the carrier of the three-way catalyst is H
The relationship is set to be smaller than the heat capacity of the C adsorbent.

In this embodiment, the width of each carrier of all the HC adsorbents A ₁ , A ₂ , A ₃ and the three-way catalysts B ₁ , B ₂ , B ₃ is set from the upstream side to the downstream side of the exhaust passage. The widths of the HC adsorbent carrier and the three-way catalyst carrier that are adjacent to each other are larger than the HC adsorbent carrier width.
The width of the carrier of the three-way catalyst is formed to be smaller than the width of the carrier of the HC adsorbent, and the relationship of the heat capacity is set.

That is, three HC adsorbents A ₁ , A ₂ , A ₃
The widths of the carriers are a ₁ , a ₂ , a ₃ and three three-way catalysts B, respectively.
_When the widths of the carriers ₁ , B ₂ and B ₃ are b ₁ , b ₂ and b ₃ , respectively, the following relationships are established. _{a 1 <a 2 <a 3 ,b 1} <b 2 <b 3 ,a 1> b 1, a
₂ > b ₂ , a ₃ > b ₃ According to the catalytic converter device 1 having such a configuration, three H
C adsorbents A ₁ , A ₂ , A ₃ and three three-way catalysts B ₁ ,
B ₂ and B ₃ are alternately arranged in series so that the three-way catalysts B ₁ , B ₂ and B ₃ are located downstream of the HC adsorbents A ₁ , A ₂ and A _3. This makes it possible to set each HC adsorbent A ₁ , A ₂ , A ₃ and each three-way catalyst B ₁ , B ₂ , B ₃ to an optimum temperature rising characteristic.

That is, as described above, the HC adsorbents A ₁ , A
₂ , A ₃ is the capacity of the HC adsorbent having a predetermined adsorption capacity divided into three, and the three-way catalysts B ₁ , B ₂ , B
₃ , the capacity of the three-way catalyst having a predetermined three-way capacity is divided into three, thereby ensuring the necessary capacity as a whole, while ensuring the necessary adsorption capacity and three-way capacity,
By positioning the small-sized HC adsorbent having a small heat mass in the preceding stage of the three-way catalyst, a decrease in exhaust temperature at the inlet of the three-way catalyst is suppressed, and the three-way catalyst can quickly reach the activation temperature.

Therefore, the desorption of HC from the HC adsorbent begins.
When it becomes full, the downstream three-way catalyst is not sufficiently activated.
As a result, the HC desorbed from the HC adsorbent is converted.
There is no risk of it being released without it, and
Emissions can be suppressed. Here, in the above embodiment
Is HC adsorbent A₁, A₂, A₃Carrier width a₁，
a₂, A₃And three-way catalyst B₁, B₂, B₃Carrier width b
₁, B₂, B₃The relationship with₁<A₂<A₃, B₁<
b₂<B₃, A₁> B₁, A₂> B₂, A ₃> B₃age
As a result, each HC adsorbent A₁, A₂, A₃HC
Desorption temperature and each three-way catalyst B₁, B₂, B₃HC purification start
The temperature relationship is as shown in FIG.

That is, as is clear from this figure, the HC adsorbent reaches the HC desorption temperature in the order of A ₁ , A ₂ and A ₃ ,
The three-way catalyst reaches the HC purification start temperature in the order of B ₁ , B ₂ , and B ₃ . Further, when the HC adsorbent and the three-way catalyst (for example, A ₁ and B ₁ ) adjacent to each other reach the HC desorption temperature, the three-way catalyst also reaches the HC purification start temperature. In addition, if the HC adsorbent on the upstream side (for example, A ₁ ) is H
When the C desorption temperature is reached, the HC adsorbent on the downstream side (for example, A ₂ ) maintains a temperature sufficiently lower than the HC desorption temperature. This is because the heat capacity of the HC adsorbent was set to be larger on the downstream side, and a predetermined space L was provided between the adjacent HC adsorbent and the three-way catalyst so that the reaction heat of the three-way catalyst was This is the result of making it difficult to reach the HC adsorbent on the downstream side.

Therefore, when the desorption of HC from the HC adsorbent starts, the three-way catalyst downstream thereof is surely activated, and the HC desorbed from the HC adsorbent is surely converted by the three-way catalyst. To be done. Then, even if HC that could not be converted by the three-way catalyst is generated, HC can be adsorbed again by the HC adsorbent downstream thereof, and it is possible to suppress the discharge of HC during cold conditions. .

Next, as described above, from the HC adsorbent to the HC
When the desorption of the three-way catalyst starts, the three-way catalyst downstream of the three-way catalyst is surely activated so that the HC desorbed from the HC adsorbent can be surely converted by the three-way catalyst. The form will be described. That is, all the HC adsorbents A ₁ , A ₂ ,
A ₃ and the three-way catalysts B ₁ , B ₂ , and B ₃ are respectively supported by HC.
The adsorbents A ₁ , A ₂ , A ₃ have a small number of carrier cells, and the three-way catalysts B ₁ , B ₂ , B ₃ have a small number of carrier cells.
_The relationship is set to be larger than the number of cells of the carriers ₁ , A ₂ , and A ₃ .

For example, the number of cells of the carrier of the HC adsorbents A ₁ , A ₂ and A ₃ is 200 to 300 [cell / inch ² ].
And the number of cells of the carriers of the three-way catalysts B ₁ , B ₂ and B ₃ is 60
It is set to 0 to 900 [cell / inch ² ]. When the number of cells of the carrier of the HC adsorbents A ₁ , A ₂ and A ₃ is reduced,
When the coating amount of the adsorption component such as zeolite is the same,
As the thickness of the coating layer of the adsorbed component in each cell increases compared to the case where the number of cells is large, the adsorbed HC
The desorption property of is a property that makes desorption difficult, that is, the desorption rate of HC becomes slower.

When the number of cells of the carrier of the three-way catalysts B ₁ , B ₂ , B ₃ is increased, it is possible to reduce the wall thickness of the cell while securing the strength of the carrier. The heat mass of the carrier can be reduced, the temperature rising property of the carrier is improved, the activation is accelerated, the HC purification start temperature is reached sooner, and the purification performance is improved. That is, if the wall of each cell of the carrier of the three-way catalysts B ₁ , B ₂ , and B ₃ is made thin, the heat mass becomes smaller, the temperature rising property of the carrier becomes better, and the activation becomes faster. It's effective.

Further, all the HC adsorbents A ₁ , A ₂ , A ₃
And the three-way catalysts B ₁ , B ₂ , and B ₃ are used to reduce the loading of platinum, palladium, rhodium, and other noble metals on the HC adsorbents A ₁ , A ₂ , and A ₃ , respectively. B ₁ ,
It is preferable to set the relationship that the amount of the noble metal supported on the carrier of B ₂ and B ₃ is larger than the amount of the supported noble metal supported on the carrier of the HC adsorbents A ₁ , A ₂ and A ₃ .

That is, by reducing the amount of the noble metal supported on the carrier of the HC adsorbents A ₁ , A ₂ , and A ₃ , the heat generation of the coating layer of the adsorbed component is reduced, and the desorption characteristics of the adsorbed HC are desorbed. The less difficult property, ie the HC desorption temperature, is reached more slowly. The HC adsorbents A ₁ , A ₂ , A ₃
It is also possible to eliminate the support of the noble metal on the carrier.

Further, by increasing the amount of the noble metal supported on the carrier of the three-way catalysts B ₁ , B ₂ , and B ₃ , the temperature rising property of the carrier is improved, the activation is accelerated, and the temperature for starting HC purification increases. As soon as it arrives, the purification performance is improved. Thus, the HC adsorbents A ₁ , A ₂ , A ₃ and the three-way catalysts B ₁ , B
_2, the cell number of each carrier B _3, HC adsorbent A _1, A _2, A
₃ and the three-way catalysts B ₁ , B ₂ , and B ₃ are loaded with noble metal on the respective carriers, and the three-way catalysts B ₁ , B ₂ , and B ₃ are set to the cell wall thickness of the carrier so that the amount of HC from the HC adsorbent is increased. When the desorption starts, the downstream three-way catalyst can be surely activated, and the HC desorbed from the HC adsorbent can be surely converted by the three-way catalyst. .

5 and 6 are views showing still another embodiment of the catalytic converter device of the present invention. In the embodiments shown in these figures, the three-way catalyst 7 is arranged in series at a predetermined position upstream of the most upstream HC adsorbent A ₁ . That is, in the embodiment of FIG. 5, the HC adsorbent A ₁ ,
The upstream side of the shell 8 in which A ₂ , A ₃ and the three-way catalysts B ₁ , B ₂ , B ₃ are alternately and serially arranged one by one such that the three-way catalyst is located downstream of the HC adsorbent. In the exhaust passage 9 of
This is a separate type structure in which a separate shell 10 provided with the three-way catalyst 7 is interposed.

In the embodiment of FIG. 6, the HC adsorbent A ₁ ,
A ₂ and A ₃ and three-way catalysts B ₁ , B ₂ and B ₃ are alternately arranged in series one by one such that the three-way catalyst is located downstream of the HC adsorbent, and the three-way catalysts are arranged in series in the shell 11. This is an integrated structure in which the original catalyst 7 is integrally housed. In such an embodiment, by arranging the three-way catalyst 7 in series at a predetermined interval at the upstream position of the HC adsorbent A _{1 at} the most upstream position,
At the time of cold start, the HC in the exhaust gas can be converted by the three-way catalyst 7 provided at a position where the exhaust temperature is higher than before being adsorbed by the HC adsorbent, and the HC purification performance can be improved.

In each of the above embodiments, three HC adsorbents A ₁ , A ₂ , A ₃ and three three-way catalysts B ₁ , B are used.
_Although the example in which ₂ and B ₃ are provided has been described, the configuration may be such that two or more (two, four ...) HC adsorbents and three-way catalysts are provided respectively.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of a catalytic converter device according to the present invention.

FIG. 2 is a cross-sectional view showing a ceramic carrier holding structure inside a shell in a catalytic converter device.

FIG. 3 is a sectional view showing a structure for holding a metal carrier in a shell in a catalytic converter device.

FIG. 4 is a characteristic diagram showing the relationship between the HC desorption temperature of each HC adsorbent and the HC purification start temperature of each three-way catalyst.

FIG. 5 is a schematic vertical sectional view of another embodiment.

FIG. 6 is a schematic vertical sectional view of still another embodiment.

[Explanation of symbols]

1 catalytic converter device 2 shells A ₁ , A ₂ , A ₃ HC adsorbents B ₁ , B ₂ , B ₃ three-way catalyst 4 cornering 6 spacer 7 three-way catalyst

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F01N 3/28 B01D 53/36 103Z (56) References JP-A-6-185342 (JP, A) JP-A-7-332073 ( JP, A) JP 8-284646 (JP, A) JP 7-232084 (JP, A) JP 10-266829 (JP, A) JP 4-141219 (JP, A) (58 ) Fields surveyed (Int.Cl. ⁷ , DB name) F01N 3/08-3/28 B01D 53/04 B01D 53/94

Claims (9)

(57) [Claims] 1. A catalytic converter device in which two or more HC adsorbents and two or more three-way catalysts are arranged alternately and in series so that the three-way catalyst is located downstream of the HC adsorbents.
The HC adsorbent has a capacity having at least a predetermined adsorption capacity as a whole, the three-way catalyst has a capacity having at least a predetermined three-way capacity as a whole, and the HC adsorbent is a three-way catalyst. a same number, call each other
A catalytic converter device which is arranged while maintaining a predetermined interval by nulling . 2. Two or more HC adsorbents and two or more ternary touches.
The medium is mixed so that the three-way catalyst is located downstream of the HC adsorbent.
In a catalytic converter arrangement arranged in series with each other,
The HC adsorbent as a whole has at least a predetermined adsorption capacity.
The capacity of the three-way catalyst is
Is a capacity with at least a predetermined ternary capacity,
The number of HC adsorbents is the same as that of the three-way catalyst,
It is characterized in that it is arranged while maintaining a predetermined interval with the user.
Catalytic converter apparatus. 3. Each carrier of the HC adsorbent and the three-way catalyst is separately discharged.
The heat capacity gradually increases from the upstream side to the downstream side of the air passage
Because of the large relationship between the HC adsorbent carrier and its downstream
Adjacent three-way catalyst carriers have heat capacity of HC adsorbent carriers
Is large, the heat capacity of the three-way catalyst carrier is that of the HC adsorbent.
The relationship is small compared to
The catalytic converter device according to 1 or 2 . 4. Two or more HC adsorbents and two or more ternary touches.
The medium is mixed so that the three-way catalyst is located downstream of the HC adsorbent.
In a catalytic converter arrangement arranged in series with each other,
Each of the HC adsorbent carrier and the three-way catalyst carrier has such a relationship that the heat capacities thereof gradually increase from the upstream side to the downstream side of the exhaust passage, and the HC adsorbent carrier and the three-way catalyst adjacent to the HC adsorbent carrier carrier are located downstream of the HC adsorbent carrier. carrier, the heat capacity of the carrier of the HC adsorbent large, catalytic converter, wherein the heat capacity of the support of the three-way catalyst is a relation of small compared to the heat capacity of the HC adsorbent instrumentation
Place 5. The width of each carrier of the HC adsorbent and the three-way catalyst
The size of the exhaust passage gradually increases from the upstream side to the downstream side.
Formed and adjacent to the HC adsorbent carrier downstream of it
The width of the carrier of the three-way catalyst is larger than that of the HC adsorbent,
The width of the carrier of the three-way catalyst is
Form the relationship to be small and set to the above-mentioned relationship of heat capacity
The catalytic converter device according to claim 3 or 4, characterized in that . 6. The HC adsorbent and the three-way catalyst carrier are HC adsorbents.
Compare the number of cells of the carrier of the adhering material with the number of cells of the carrier of the three-way catalyst.
1 to 5, characterized in that the relationship is set to be small.
The catalytic converter device according to any one of the above . 7. The wall of each cell of the three-way catalyst carrier is made thin.
It formed , The catalytic converter apparatus in any one of Claims 1-6 characterized by the above-mentioned. 8. The HC adsorbent and each carrier of the three-way catalyst are
The amount of precious metal supported on the carrier of the adhering material depends on the amount of precious metal supported on the carrier of the three-way catalyst.
The catalytic converter device according to any one of claims 1 to 7, wherein the amount is set to be smaller than the amount of metal carried . 9. A further upstream position of the HC adsorbent at the most upstream position.
9. The catalytic converter device according to claim 1, wherein the three-way catalysts are arranged in series at a predetermined interval .