JPH08505U - Exhaust gas purification device for internal combustion engine - Google Patents

Abstract

(57) [Summary] [Structure] Exhaust gas introduced from the high temperature side gas passage by introducing the high temperature exhaust gas of the internal combustion engine 2 into the high temperature side gas passage of the heat exchanger 21 in which the catalyst is fixed in the low temperature side gas passage. To the adsorption device 22,
An exhaust gas purification device configured to guide the exhaust gas that has left the adsorption device 22 to the low temperature side gas flow path of the heat exchanger 21, and to treat the exhaust gas with a catalyst fixed to the low temperature side gas flow path. [Effect] At the time of startup, the exhaust gas temperature at the entrance of the adsorption device is lowered, and the efficiency of adsorption of harmful gas by the adsorbent is improved. It is possible to prevent the discharge of gas.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an exhaust emission control device for an internal combustion engine.

[0002]

[Prior art]

 Almost all internal combustion engines emit various harmful gases in addition to carbon dioxide and water vapor, depending on their types and fuels. Emissions of harmful gases are especially high when the cylinder temperature is low when the engine is started, so some kind of exhaust gas purification treatment is necessary.

For example, in a diesel engine that uses methanol as a fuel, formaldehyde and other various organic substances generated by incomplete combustion of methanol are included in the exhaust gas and discharged. Of these, formaldehyde not only has a bad odor, but is also harmful to the human body, so it is not desirable to release it directly into the atmosphere. Therefore, it was first considered to oxidize and decompose organic compounds such as formaldehyde using a catalyst composed of a noble metal such as platinum, palladium, cobalt, and nickel, and then release them into the atmosphere. However, since the precious metal catalyst requires a high temperature of about 200 ° C or more to exert its activity, the exhaust gas temperature does not reach 100 ° C as in the warm-up operation immediately after starting a cold engine. If it has little effect. In addition, since the emission of organic substances such as formaldehyde and unburned methanol is particularly large while the engine temperature is low, the exhaust gas pollution during warm-up is extremely high even when exhaust treatment with a catalyst is performed.

In order to solve the above-mentioned problems in the catalytic treatment, in the devices of JP-A-62-5820 and JP-A-62-10223, adsorption is carried out in the exhaust passage between the catalyst device and the internal combustion engine. A device is installed so that the adsorbent adsorbs formaldehyde, methanol, etc., which are discharged until the catalyst becomes active after the engine is started. Formaldehyde adsorbed on the adsorbent is desorbed as the exhaust gas temperature rises, but at that time the temperature of the catalyst also becomes sufficiently high and it shows organic matter decomposing ability. Air emission of concentrated pollutant exhaust is avoided.

[0005]

[Problems to be solved by the device]

 However, in an exhaust gas purification device equipped with an adsorption device in front of the catalyst device, the exhaust gas temperature at the catalyst device inlet at startup is higher than that without the adsorption device because the heat capacity of the adsorption device and the exhaust gas temperature decrease due to surface heat radiation. Will be delayed. Therefore, on the one hand, the adsorbing device which holds the harmful gas until the temperature of the catalyst becomes active has a disadvantage that the temperature rise of the catalyst is delayed and the start-up of the catalyst device is delayed.

An object of the present invention is to solve the above-mentioned problems and to provide an exhaust emission control device improved so that a catalyst can be activated in a shorter time.

[0007]

[Means for Solving the Problems]

 The present invention succeeded in achieving the above object, and a catalyst device installed in an exhaust passage of an internal combustion engine to treat exhaust gas, and an adsorption device installed in an exhaust passage between the catalyst device and exhaust gas. In the exhaust gas purification device having the above, a catalyst device having a catalyst fixed in the low temperature side gas passage of the heat exchanger is used, and the exhaust gas flowing from the internal combustion engine to the adsorption device is made to flow into the high temperature side gas passage of the heat exchanger. It is characterized by having done.

[0008]

[Action]

 In the exhaust gas purification device of the present invention, the exhaust gas of the internal combustion engine first passes through the high temperature side gas flow path of the heat exchanger and then enters the adsorption device, and then the low temperature side gas flow path of the heat exchanger (the catalyst is fixed). After that, it is connected to the exhaust pipe of the internal combustion engine so as to be discharged into the atmosphere through the muffler.

In the heat exchanger, heat exchange is performed between the high temperature exhaust gas immediately after it leaves the internal combustion engine and the adsorbent-treated low temperature exhaust gas. As a result, at the time of starting, the exhaust gas temperature at the entrance of the adsorber is lower than that of a conventional exhaust gas purifying device without a heat exchanger, and the adsorbent can more efficiently adsorb the harmful gas. Further, since the heat from the hot exhaust gas is directly transferred to the catalyst via the heat transfer wall of the heat exchanger, the catalyst is heated to the working temperature in a short time and becomes active.

The adsorbent and catalyst used in the exhaust gas purification apparatus of the present invention are not limited, and can be arbitrarily selected according to the type of internal combustion engine and the type of fuel.

[0011]

【Example】

 FIG. 1 shows a usage state of an exhaust emission control device 20 according to an embodiment of the present invention. The exhaust gas purification device 20 comprises a heat exchanger 21 and an adsorption device 22 which are catalytic devices, and is connected between the exhaust port 3 of the diesel engine 2 and the muffler 4. The heat exchanger 21 has a high temperature side gas flow path inlet 23 connected to the exhaust port 3 by a pipe 24 and an outlet 25 connected to an inlet 27 of the adsorption device 22 by a pipe 26. In the low temperature side gas flow path of the heat exchanger 21, an inlet 28 is connected to an outlet 30 of the adsorption device 22 by a pipe 29, and an outlet 31 is connected to the muffler 4 by a pipe 32. The catalyst is fixed to the low temperature side gas flow path of the heat exchanger 21.

Based on the above connection, the exhaust gas of the diesel engine 2 flows in the order of the high temperature side gas flow path of the heat exchanger 21 → the adsorption device 22 → the low temperature side gas flow path with the catalyst of the heat exchanger 21 → the muffler 4 in the atmosphere. Is released to.

The heat of the high temperature exhaust gas immediately after exiting from the exhaust port 3 is transferred to the catalyst in the low temperature side gas flow path via the heat transfer wall of the heat exchanger 21. As a result, the temperature rise of the catalyst at the time of starting is much faster than in the case where the heat exchanger 21 is not provided, and the catalytic activity is rapidly developed. Since the exhaust gas having a lowered temperature passes through the heat exchanger 21 into the adsorption device 22, the temperature rise of the adsorbent is delayed, and the temperature condition advantageous for adsorption is maintained for a long time.

[0014]

[Effect of device]

 In the present invention, as described above, the exhaust gas of the internal combustion engine first passes through the high temperature side gas flow path of the heat exchanger and then enters the adsorption device, and then enters the low temperature side gas flow path of the heat exchanger and undergoes catalytic treatment there. As a result, heat is exchanged between the high-temperature internal combustion engine exhaust before entering the adsorption device and the low-temperature adsorbent-treated exhaust gas and the catalyst. The exhaust gas temperature at the inlet of the adsorption device is lower than that of the conventional exhaust gas purification device without an exchanger, the efficiency of adsorption of harmful gas by the adsorbent is improved, and the temperature rise of the catalyst is accelerated, so that the catalyst can quickly activate its activity. become.

Therefore, according to the present invention, it is possible to surely purify the exhaust gas at the time of starting the engine, and the adsorption capacity of the adsorption device can be made smaller than that of the conventional device, which reduces the heat capacity of the adsorption device. This brings about a remarkable effect of making the catalyst device start up faster.

[Submission date] May 27, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

[0011]

【Example】

 FIG. 1 is an exhaust emission control device according to an embodiment of the present invention.1 is the exhaust port 3 of the diesel engine 2 The use state connected between the muffler 4 and the muffler 4 is shown. The exhaust gas purification device 1 is a catalyst device. It consists of a heat exchanger 5 and an adsorption device 6. Heat exchanger 5 Is the high temperature side gas flow path 7 Entrance of8Is a pipeline9To the exhaust port 310Is a pipeline11Adsorption device6Entrance of12, Respectively. Heat exchanger5Low temperature side gas flow path1 Three The entrance14Is a pipeline15By adsorption device6Exit of16Connected to the exit17 Is a pipeline18Is connected to the muffler 4. The catalyst is a heat exchanger5Low temperature side gas flow path13Is stuck to.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012] Based on the above connection, the exhaust of the diesel engine 2 is in this order of the catalyst-low temperature side gas flow path 13 → the muffler 4 on the high temperature side air passage 7 → adsorber 6 → the heat exchanger 5 of the heat exchanger 5 It is released into the atmosphere.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

The heat of the high-temperature exhaust gas immediately after exiting from the exhaust port 3 is transferred to the catalyst in the low temperature side gas flow path 13 via the heat transfer wall of the heat exchanger 5 . As a result, the temperature rise of the catalyst at the time of starting is much faster than in the case where the heat exchanger 5 is not provided, and the catalytic activity is rapidly developed. Since the exhaust gas having a lowered temperature enters the adsorption device 6 through the heat exchanger 5 , the temperature rise of the adsorbent is delayed, and the temperature condition advantageous for adsorption is maintained for a long time.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

[0015] Thus, the exhaust purifying engine during starting in accordance with the present invention is reliably course, the amount of adsorption capacity i.e. the adsorbent required for the adsorption device can be a Herasuko than conventional devices It becomes, whereby there is a synergistic effect that Ri rising of the catalytic converter to reduce the heat capacity of the adsorber can be further quickly. Furthermore, reducing the amount of adsorbent required has the effect of reducing the pressure loss in the exhaust system . Pressure loss due to the exhaust gas is passed through the adsorption device is not limited in warmup, since it is intended to neither inevitable steady operation, pressure loss is small internal combustion engine with the exhaust purification device attached It has a great significance in minimizing the output reduction of .

[Brief description of drawings]

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

[Explanation of symbols]

 2: Diesel engine 20: Exhaust gas purification device of the present invention 21: Heat exchanger 22: Adsorption device 23: High temperature side gas passage inlet 25: High temperature side gas passage outlet 28: Low temperature side gas passage inlet 31: Low temperature side gas Channel outlet

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[Procedure amendment]

[Submission date] May 27, 1994

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] Explanation of code

[Correction method] Change

[Correction content]

[Explanation of Codes] 1: Exhaust gas purification device of the present invention 2: Diesel engine 3: Exhaust port of diesel engine 2 4: Muffler 5: Heat exchanger 6: Adsorption device 7: High temperature side gas flow path 13: Low temperature side gas flow Road

[Procedure Amendment 7]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

FIG.

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Claims (1)

[Scope of utility model registration request] 1. An exhaust purification device having a catalyst device installed in an exhaust passage of an internal combustion engine for treating exhaust gas, and an adsorption device installed in an exhaust passage between the catalyst device and the internal combustion engine for treating exhaust gas. A catalyst device in which a catalyst is fixed in a low-temperature side gas flow path of a heat exchanger is used, and exhaust gas flowing from an internal combustion engine to an adsorption device is caused to flow to a high-temperature side gas flow path of the heat exchanger. Exhaust purification device for an internal combustion engine.