JP2006057586A - Catalyst temperature control case - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalyst temperature control case for preventing excessive temperature rise of catalysts provided in an exhaust system for an internal combustion engine while quickening warm-up. <P>SOLUTION: The case comprises a case body 11 arranged around the catalysts 21, 22 in the exhaust system for the internal combustion engine 20, an air intake 11a formed in the case body 11 for introducing air into the case body 11, air outlets 11b, 11c formed in the case body 11 for exhausting the air introduced from the air intake 11a, and open/closed doors 11a-11c provided in the air intake 11a or the air outlets 11b, 11c for opening/closing depending on the temperatures of the catalysts 21, 22 to control the air to be introduced into the case body. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a catalyst temperature adjustment case capable of quickly warming up a catalyst provided in an exhaust system of an internal combustion engine and adjusting the temperature of the catalyst to prevent the catalyst temperature from rising excessively.

The exhaust gas purification catalyst exhibits an exhaust gas purification function in a state of a temperature (activation temperature) or higher determined by its specifications. Therefore, it is necessary to warm up above the activation temperature in a short time after the start of the cooler. On the other hand, if the temperature rises too much, the catalyst may be melted. Therefore, conventionally, when the catalyst temperature rises too much, the fuel injection amount is increased and the catalyst temperature is lowered by the latent heat of vaporization of the fuel. However, when the fuel injection amount is increased, exhaust gas components are increased and fuel consumption is also deteriorated. Therefore, in Patent Document 1, the diameter-enlarged portion that accommodates the catalyst is directed outward in the vehicle width direction, so that the traveling wind is applied to the diameter-enlarged portion and the catalyst accommodated inside is cooled.
Japanese Patent Laid-Open No. 2001-3743

  However, in Patent Document 1, a sufficient cooling performance cannot be ensured because the traveling wind only hits a part of the enlarged diameter portion that houses the catalyst.

  The present invention has been made paying attention to such a conventional problem, and quickly warms up the catalyst provided in the exhaust system of the internal combustion engine and prevents the catalyst temperature from excessively rising. The object is to provide a catalyst temperature adjustment case.

  The present invention solves the above problems by the following means. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected, it is not limited to this.

  The present invention includes a case body (11) disposed around an exhaust system catalyst (21, 22) of an internal combustion engine (20) and the case body (11), and introduces air into the case body. A possible air intake (11a), an air outlet (11b, 11c) formed in the case body (11) and capable of discharging air introduced from the air intake (11a), and the air intake (11a) or an open / close door (11a to 11c) which is provided at the air outlet (11b, 11c) and can be opened and closed according to the temperature of the catalyst (21, 22) to adjust the introduction of air into the case body. 11c).

  According to the present invention, the air intake port through which air can be introduced into the inside of the case body that houses the catalyst, the air outlet port through which air introduced from the air intake port can be discharged, and the opening / closing operation according to the catalyst temperature. In addition, an open / close door that can adjust the introduction of air into the case body is provided, so when the catalyst temperature is low, the open / close door is closed to speed up the warming, and when the catalyst temperature is high, the open / close door is opened. It can be closed to prevent the catalyst temperature from rising too much.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings.
(First embodiment)
FIG. 1 is a diagram showing a first embodiment of a catalyst temperature adjustment case according to the present invention. In addition, the broken line in a figure shows the flow of air.

  The catalyst temperature adjustment case 10 is disposed around the first catalyst 21 and the second catalyst 22 disposed in the exhaust passage 20a of the engine 20, that is, the case main body 11 that houses the first catalyst 21 and the second catalyst 22 therein. Have The types of the first catalyst 21 and the second catalyst 22 are not particularly limited. For example, the first catalyst 21 is an HC (hydrocarbon) trap catalyst, and the second catalyst 22 is a NOx storage catalyst. In this embodiment, the activation temperature of these catalysts is assumed to be about 300 ° C., but the scope of rights is not limited to this.

  An air inlet 11a and air outlets 11b and 11c are formed in the case body 11 of the catalyst temperature adjusting case 10. The air intake port 11a is formed on the upstream side of the catalyst temperature adjustment case 10 (the side close to the exhaust manifold 23) and opens forward of the vehicle.

  The air outlet 11b is formed on the downstream side (in the direction away from the exhaust manifold 23) from the air inlet 11a and opens upward of the vehicle.

  Similarly to the air outlet 11b, the air outlet 11c is also formed downstream (in a direction away from the exhaust manifold 23) from the air intake 11a. The air outlet 11c opens below the vehicle.

  The air intake port 11a and the air outlet ports 11b and 11c are formed of bimetal formed by bonding two types of metal plates having different linear expansion coefficients, and are opened and closed according to temperature (introduction door 12, upper lead-out door 13, lower portion). A lead-out door 14) is attached.

  FIG. 2 is a diagram for explaining the characteristics of the bimetal forming the door.

  As shown in FIG. 2, the opening / closing temperature of the bimetal door can be adjusted by the material.

  For example, when a bimetal obtained by bonding a metal plate of monet metal (Ni—Cu alloy) and a metal plate of 34 to 42% Ni steel is used, the door is opened and closed at about 250 ° C.

  Moreover, if a bimetal obtained by bonding a metal plate of 20% Ni steel and a metal plate of 42 to 54% Ni steel is used, the door is opened and closed at about 400 ° C.

  In this way, the switching temperature can be adjusted by adjusting the material, size, etc. of the metal plate.

  FIG. 3 is a view showing a state where the opening / closing door of the catalyst temperature adjustment case is opened.

  When the catalyst temperature is low, such as during cold start, the inlet door 12, the upper outlet door 13, and the lower outlet door 14 of the catalyst temperature adjustment case 10 are closed as shown in FIG. At this time, the air flows around the case body 11 as indicated by the broken line arrows, and does not flow into the inside.

  Therefore, since the introduction door 12, the upper derivation door 13, and the lower derivation door 14 are closed while the first catalyst 21 and the second catalyst 22 are warming up before activation, the surroundings of the first catalyst 21 and the second catalyst 22 are closed. The air stays in the air and the temperature of the first catalyst 21 and the second catalyst 22 rises early.

  The first catalyst 21 and the second catalyst 22 are warmed up, and the heat is transmitted to the introduction door 12, the upper derivation door 13, and the lower derivation door 14, and the introduction door 12, the upper derivation door 13, and the lower derivation door 14 are sufficient. When heated, the introduction door 12, the upper derivation door 13, and the lower derivation door 14 are opened. Then, air flows in from the air intake port 11a and flows out of the air flow ports 11b and 11c. At this time, heat is taken from the first catalyst 21 and the second catalyst 22 and cooled.

  The introduction door 12, the upper derivation door 13, and the lower derivation door 14 are manufactured from the same material that opens and closes at approximately 300 ° C. About 300 ° C. is the ambient temperature around the catalyst when the catalyst is activated. However, the exhaust temperature is high on the side close to the engine and is about 800 ° C. when it flows into the first catalyst 21, but is about 500 ° C. when it flows into the second catalyst 22. Therefore, there is a time difference in the warm-up time between the first catalyst 21 and the second catalyst 22, and as shown in the timing chart of FIG. 4, first, after the introduction door 12 is opened at time t11, it is derived upward at time t12. The door 13 and the lower outlet door 14 are opened. Therefore, since all the introduction doors 12, the upper derivation doors 13, and the lower derivation doors 14 are closed until time t11, the first catalyst 21 and the second catalyst 22 rise early. Thereafter, when the upper outlet door 13 and the lower outlet door 14 are opened at time t12, the air flowing in from the air intake port 11a flows out of the air outlet ports 11b and 11c, and the air flows, and the first catalyst 21 and The temperature rise of the second catalyst 22 is suppressed.

  According to the present embodiment, the bimetal introduction door 12, the upper derivation door 13, and the lower derivation door 14 that open and close depending on the temperature are provided in the openings 11 a to 11 c of the case body 11. Therefore, when the temperature of the catalyst is low, such as at the time of cold start, the introduction door 12, the upper derivation door 13, and the lower derivation door 14 are closed, so that the catalyst can be warmed up quickly.

  And after catalyst warm-up, since the introduction door 12, the upper derivation door 13, and the lower derivation door 14 open, the air which flowed in from the air intake port 11a will flow out of the air outflow port 11b11c, and air flows, An excessive temperature rise of the catalyst can be suppressed.

  The introduction door 12, the upper derivation door 13, and the lower derivation door 14 were manufactured from the same material. Therefore, the cost can be kept low.

(Second Embodiment)
FIG. 5 is a graph showing the characteristics of the second embodiment of the catalyst temperature adjustment case according to the present invention. In the following embodiments, the same reference numerals are given to the portions that perform the same functions as those of the above-described embodiments, and overlapping descriptions are omitted as appropriate.

  In the second embodiment, the introduction door 12 is normally open, or the air intake port 11a is not provided with an opening / closing door. The upper outlet door 13 and the lower outlet door 14 are made of the same material that opens and closes at approximately 300 ° C.

  If it does in this way, since the introduction door 12 is a normally open state, the temperature rise of the 1st catalyst 21 will become late compared with the case of 1st Embodiment. And if the upper derivation door 13 and the lower derivation door 14 open at time t22, air will flow and an increase in catalyst temperature will be controlled.

  If it does in this way, it will become easy to flow air inside the catalyst temperature adjustment case. Therefore, the second embodiment is suitable for the case where the air does not easily flow in the layout in the engine room and importance is attached to the cooling of the catalyst.

(Third embodiment)
FIG. 6 is a graph showing the characteristics of the third embodiment of the catalyst temperature adjustment case according to the present invention.

  The introduction door 12 and the upper outlet door 13 are manufactured from the same material that opens and closes at approximately 300 ° C. The lower outlet door 14 is normally open, or no door is provided at the air outlet 11c.

  If it does in this way, since introduction door 12 is closed until time t31, air will stay around the 1st catalyst 21, and temperature of the 1st catalyst 21 will rise early. And when the introduction door 12 opens at the time t31, air will flow and the temperature rise of the 1st catalyst 21 will be suppressed. However, since the upper outlet door 13 is closed at this time, the air warmed by the second catalyst 22 stays near the upper portion of the second catalyst 22. When the upper outlet door 13 is opened at time t32, the air flowing in from the air intake port 11a flows around the first catalyst 21 and the second catalyst 22 and flows out from the air outlets 11b and 11c.

  According to the present embodiment, when the introduction door 12 opens at time t31, air immediately flows, and the temperature increase of the first catalyst 21 can be prevented early.

(Fourth embodiment)
FIG. 7 is a diagram showing the characteristics of the fourth embodiment of the catalyst temperature adjustment case according to the present invention.

  The introduction door 12 and the lower outlet door 14 are manufactured from the same material that opens and closes at approximately 300 ° C. The upper outlet door 13 is made of a material that opens and closes at a higher temperature, for example, approximately 400 ° C.

  If it does in this way, since the introduction door 12 is closed until time t41, air stays around the 1st catalyst 21, and the temperature of the 1st catalyst 21 rises early. And if the downward derivation | leading-out door 14 opens at the time t42, the air which flowed in from the air intake port 11a will flow out from the air outflow port 11c. Thereby, the temperature rise of the 1st catalyst 21 is suppressed. However, since the upper outlet door 13 is closed at this time, the air heated by the second catalyst 22 stays in the vicinity of the upper portion of the second catalyst 22. When the upper outlet door 13 is opened at time t43, the air flowing in from the air intake port 11a flows around the first catalyst 21 and the second catalyst 22 and flows out from the air outlets 11b and 11c. Therefore, the temperature rise of the second catalyst 22 is also suppressed.

  According to this embodiment, since the introduction door 12 is closed until time t41, the temperature of the first catalyst 21 rises early. And if the downward derivation | leading-out door 14 opens at the time t42, the temperature rise of the 1st catalyst 21 will be suppressed. Further, when the upper outlet door 13 is opened at time t43, the temperature rise of the second catalyst 22 is also suppressed. In this way, the temperature of the catalyst can be accurately adjusted according to the activation temperature of the catalyst.

  The present invention is not limited to the embodiment described above, and various modifications and changes can be made within the scope of the technical idea, and it is obvious that these are equivalent to the present invention.

  For example, the open / close temperature of the open / close door is not limited to the above temperature, and may be appropriately adjusted according to the catalyst specifications.

It is a figure which shows 1st Embodiment of the catalyst temperature adjustment case by this invention. It is a figure explaining the characteristic of the bimetal which forms an opening-and-closing door. It is a figure which shows the state which the opening / closing door of the catalyst temperature adjustment case opened. It is a timing chart which shows the opening / closing timing of the opening / closing door of 1st Embodiment. It is a figure which shows the characteristic of 2nd Embodiment of the catalyst temperature adjustment case by this invention. It is a figure which shows the characteristic of 3rd Embodiment of the catalyst temperature adjustment case by this invention. It is a figure which shows the characteristic of 4th Embodiment of the catalyst temperature adjustment case by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Catalyst temperature adjustment case 11 Case main body 11a Air intake port 11b, 11c Air outflow port 12 Introduction door (open / close door)
13 Upper outlet door (open / close door)
14 Downward door (open / close door)
20 engine (internal combustion engine)
21 First catalyst 22 Second catalyst

Claims (11)

A case body disposed around the exhaust system catalyst of the internal combustion engine;
An air intake port formed in the case body and capable of introducing air into the case body;
An air outlet formed in the case body and capable of discharging air introduced from the air intake;
An open / close door provided at the air inlet or the air outlet, which can be opened / closed according to the temperature of the catalyst and can adjust the introduction of air into the case body; and
A catalyst temperature adjustment case having The open / close door is formed of a bimetal in which two types of metal plates having different linear expansion coefficients are bonded together.
The catalyst temperature adjustment case according to claim 1. The air intake is formed to open forward of the vehicle when mounted on the vehicle,
The air outlet is formed on the downstream side of the air intake with respect to the air flow direction, and includes an upper opening that opens to the vehicle upper side and a lower opening that opens to the vehicle lower side.
The catalyst temperature adjustment case according to claim 1 or 2, characterized in that The open / close door includes an introduction door portion that can open and close the air intake port, an upper lead-out door portion that can open and close an upper opening portion of the air outlet, and a lower lead-out that can open and close the lower opening portion of the air outlet. With a door,
The introduction door part, the upper derivation door part, and the lower derivation door part open and close at substantially the same temperature.
The catalyst temperature adjustment case according to claim 3. The open / close door includes an introduction door portion that can open and close the air intake port, an upper lead-out door portion that can open and close an upper opening portion of the air outlet, and a lower lead-out that can open and close the lower opening portion of the air outlet. With a door,
The upper derivation door part and the lower derivation door part are opened later than the opening timing of the introduction door part,
The catalyst temperature adjustment case according to claim 3. The open / close door includes an upper derivation door part capable of opening and closing an upper opening part of the air outlet, and a lower derivation door part capable of opening and closing a lower opening part of the air outlet,
The upper outlet door part and the lower outlet door part open and close at substantially the same temperature,
The catalyst temperature adjustment case according to claim 3. The open / close door includes an upper derivation door part capable of opening and closing an upper opening part of the air outlet, and a lower derivation door part capable of opening and closing a lower opening part of the air outlet,
The upper derivation door and the lower derivation door are opened and closed at substantially the same timing.
The catalyst temperature adjustment case according to claim 3. The open / close door includes an introduction door portion that can open and close the air intake port, and a lead-out door portion that can open and close an upper opening portion of the air outlet port,
The introduction door part and the outlet door part open and close at substantially the same temperature,
The catalyst temperature adjustment case according to claim 3. The open / close door includes an introduction door portion that can open and close the air intake port, and a lead-out door portion that can open and close an upper opening portion of the air outlet port,
The lead-out door portion opens later than the opening timing of the introduction door portion;
The catalyst temperature adjustment case according to claim 3. The open / close door includes an introduction door portion that can open and close the air intake port, an upper lead-out door portion that can open and close an upper opening portion of the air outlet, and a lower lead-out that can open and close the lower opening portion of the air outlet. With a door,
The opening / closing temperature of the upper outlet door is higher than the opening / closing temperature of the lower outlet door,
The catalyst temperature adjustment case according to claim 3. The open / close door includes an introduction door portion that can open and close the air intake port, an upper lead-out door portion that can open and close an upper opening portion of the air outlet, and a lower lead-out that can open and close the lower opening portion of the air outlet. With a door,
The upper lead-out door portion opens later than the timing when the lower lead-out door portion opens,
The catalyst temperature adjustment case according to claim 3.

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