JP2003301716A - Exhaust emission control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent exhaust of HC by an ignition lag of an exhaust re- combustor 21 for early activating a catalyst, and to avoid adverse influence by desorption of the adsorbed HC. <P>SOLUTION: The exhaust re-combustor 21 is arranged on the upstream side of a catalyst device 23 of an exhaust passage 14 of an internal combustion engine 1, and an HC adsorbent 18 for adsorbing HC is interposed on the upstream side of the exhaust re-combustor. A secondary air pump 20 has an upstream side air introducing part 27 and a downstream side air introducing part 29, and is controlled by opening-closing valves 28 and 30. An engine control unit 26 burns gas again by adding secondary air by enriching the air-fuel ratio of the internal combustion engine 1 via a fuel injection valve 8. The secondary air is introduced from the downstream side of the HC adsorbent 18 up to actually starting combustion, and is switched to introduce the secondary air from the upstream side after starting the combustion. The separation of the HC is promoted by the passing of the secondary air. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust gas purification device for an internal combustion engine, and more particularly to an exhaust gas purification device for purifying exhaust gas immediately after starting.

[0002]

2. Description of the Related Art A catalyst device carrying a catalyst made of a noble metal (platinum, rhodium, etc.) or another metal has been widely used for purification of exhaust gas discharged from an internal combustion engine of an automobile. Such a catalyst purifies by oxidizing and reducing HC, CO, NOx and the like which are harmful components in the exhaust gas. By the way, in order to obtain this catalytic action, the exhaust gas temperature must be high, for example, a temperature of about 300 ° C. is necessary. However, immediately after starting the internal combustion engine,
Exhaust gas temperature is low and catalyst activation temperature (300 ° C
Before and after), the exhaust harmful components are hardly purified, and a relatively large amount of exhaust harmful substances is released into the atmosphere.

Therefore, in order to solve the above-mentioned problem, further on the upstream side of the catalyst device arranged in the exhaust system of the internal combustion engine,
It is known that an exhaust gas re-combustor is provided, and a combustible exhaust gas is combusted in this re-combustor immediately after starting, and the catalyst is activated early by the heat of combustion (Tokuhyohei 6-5).
08409, etc.). This exhaust gas purification device does not inject fuel into the exhaust gas recombustor, but makes the air-fuel ratio of the internal combustion engine rich and supplies secondary air to generate combustible exhaust gas containing combustible components and air. However, since the combustible gas is burned by the ignition device, the catalyst can be activated early with a very simple structure. Moreover, since HC and CO can be purified by combustion even before the catalyst is activated, it can be said that this is a very effective means for cleaning the entire exhaust gas.

[0004]

However, in the above-mentioned conventional exhaust gas purification apparatus, although there is no problem if exhaust gas re-combustion is carried out immediately after starting, in reality, the gas in the exhaust gas re-combustor is burned in the combustible region. Since there is a delay of about several seconds in controlling the temperature and igniting it, there is a disadvantage that a relatively large amount of unburned HC is discharged during that period.

In particular, if the air-fuel ratio of the air-fuel mixture burned in the internal combustion engine is set to a rich state on the premise of operating the exhaust gas recombustor, HC, which is unburned fuel, also increases accordingly. The emission of HC due to the delay of combustion becomes a big problem.

It is also possible to arrange the HC adsorbent on the upstream side in order to prevent the discharge of HC immediately after such a start. However, the adsorbed HC then rises in temperature of this HC adsorbent. As it is desorbed and flows into the catalyst device, the air-fuel ratio control is affected for a relatively long time, which is not preferable.

[0007]

In order to solve the above problems, the present invention arranges an HC adsorbent on the upstream side of an exhaust gas recombustor for heating a catalyst device to start exhaust gas recombustion. Prevents the discharge of HC during
By introducing the secondary air from the upstream side of the C adsorbent, the desorption of HC was quickly completed.

That is, an exhaust gas purifying apparatus for an internal combustion engine according to a first aspect of the present invention is an exhaust gas reburner equipped with a catalyst device provided in an exhaust passage of the internal combustion engine, and an upstream side of the catalytic device and having an ignition means. An unburned component supply means for temporarily increasing the unburned component in the exhaust gas of the internal combustion engine for reburning in the exhaust gas recombustor, and the exhaust gas for reburning in the exhaust gas recombustor. 2 in the exhaust gas upstream of the reburner
In an exhaust gas purification device for an internal combustion engine, comprising: a secondary air supply device for supplying secondary air, H for adsorbing HC (hydrocarbon component) in exhaust gas on the upstream side of the exhaust gas recombustor.
A C adsorbent is provided, and a secondary air introduction unit of the secondary air supply device is arranged upstream of the HC adsorbent.

The unburned component supply means may be, for example, the second aspect.
As described above, the air-fuel ratio control means temporarily sets the air-fuel ratio of the internal combustion engine to the rich state.

In the exhaust gas purification device thus constructed, the exhaust gas combustor operates in order to early activate the catalyst device at the time of low temperature starting and the like. That is, the exhaust gas containing combustible components (CO, HC, H ₂ etc.) discharged from the internal combustion engine is supplied to the exhaust gas reburner after O ₂ is added by the secondary air and after passing through the HC adsorbent. It Then, combustion is performed in the exhaust gas recombustor by ignition of ignition means such as a spark plug, and the catalyst device is heated. The HC adsorbent is made of, for example, zeolite or the like, and has a property of adsorbing HC at a low temperature lower than a predetermined temperature and desorbing the adsorbed HC at a temperature higher than a predetermined desorption temperature. . Therefore, when the exhaust gas passes through the HC adsorbent, HC
Since most of the HC is adsorbed, the HC is prevented from being discharged to the outside even if there is an ignition delay in the exhaust gas recombustor.

For ignition in the exhaust gas recombustor, CO,
H ₂ and O ₂ are sufficient, and even if HC is removed by the adsorbent, combustion in the second exhaust combustor is not hindered.

As a secondary effect, by adsorbing HC in advance, the combustion temperature in the exhaust combustor can be slightly suppressed. That is, since only CO and H ₂ are combusted, the combustion temperature is lowered, for example, from about 950 ° C to about 750 ° C. Deterioration of the catalyst is generally promoted as the temperature rises, but particularly at 900 ° C. or higher, the catalyst exhibits a characteristic of rapid deterioration. If the combustion temperature can be lowered from about 950 ° C. to about 750 ° C. as described above, catalyst deterioration can be sufficiently suppressed and the overall exhaust performance can be improved over a long period of time. In particular, since the activation temperature of the catalyst is about 300 ° C., it is possible to obtain a sufficient catalyst early activation effect even with a combustion gas of about 750 ° C.

The HC adsorbed on the HC adsorbent immediately after starting is desorbed as the temperature of the HC adsorbent rises. Here, desorption from the adsorbent depends on the adsorbent temperature,
As shown in FIG. 6, it also depends on the flow rate of the gas passing through the adsorbent per unit time. In the present invention, the secondary air is H
Since it is introduced from the upstream side of the C adsorbent and passes through the HC adsorbent, desorption is completed in a short period of time.

Further, in the invention of claim 3, the above 2
Secondary air introduction units by the secondary air supply device are provided on both the upstream side and the downstream side of the HC adsorbent, and the introduction of air from each is controlled according to the conditions.

According to the invention of claim 4, which is a more specific form of the invention of claim 3, means for detecting the start of combustion of the exhaust gas recombustor, and secondary air from the inlet on the downstream side before the start of combustion. And a secondary air control means for introducing secondary air from the upstream inlet after the start of combustion. As the above combustion start detecting means, for example, a temperature sensor is provided in the exhaust gas recombustor, and the combustion start is detected from the temperature of the exhaust gas recombustor.

That is, during the combustion delay period in the exhaust gas re-combustor, by introducing the secondary air from the downstream side of the HC adsorbent, only the exhaust gas flows through the HC adsorbent, HC can be efficiently adsorbed on the HC adsorbent. And after the start of combustion in the exhaust reburner,
Desorption of HC can be promoted by introducing the secondary air from the upstream side of the HC adsorbent.

Further, in the invention of claim 6, between the stop of the secondary air from the downstream introduction portion and the start of the introduction of the secondary air from the upstream introduction portion due to the start of combustion of the exhaust gas recombustor, An appropriate overlap period is provided.

There is still a slight delay before the secondary air introduced from the upstream introduction section actually reaches the exhaust gas recombustor. In particular, since it is located further upstream than the downstream introduction section, the delay is relatively large with respect to the downstream introduction section. Therefore, if the secondary air is stopped from the downstream introduction section and the secondary air is started to be introduced from the upstream introduction section at the same time, the air supply to the exhaust gas recombustor is temporarily insufficient, resulting in combustion failure. May be stable. On the other hand, in the invention of claim 6, after the introduction of the secondary air from the upstream introduction section is started, the introduction of the secondary air in the downstream introduction section is stopped after the overlap period elapses. The actual air supply to the exhaust gas recombustor is continuous.

Since the flow velocity of the exhaust gas becomes faster in the higher speed range according to the engine speed, for example, in the invention of claim 7, the overlap time, which is the overlap period, is higher on the high speed side according to the engine speed. It is set to be short.

[0020]

According to the present invention, the HC exhausted during the ignition delay period until reburning actually occurs in the exhaust gas recombustor for heating the catalyst device is trapped by the HC adsorbent, and the adsorbed HC is Since the desorption is carried out early by utilizing the flow of the next air, it is possible to surely prevent the emission of HC discharged from the internal combustion engine to the atmosphere at the time of starting and to promote the early activation of the catalyst. , The effect of desorption of HC adsorbed on the HC adsorbent can be eliminated early and normal exhaust gas purification by the catalyst can be started, and as a whole, the harmful components emitted at the time of cold start can be significantly reduced. It becomes possible.

Particularly, according to the inventions of claims 3 and 4, the secondary air is introduced from the downstream side of the HC adsorbent until the start of combustion in the exhaust gas recombustor, and the secondary air is introduced from the upstream side with the start of combustion. Since it is switched to introduction, it is possible to achieve both efficient adsorption of HC during the delay of exhaust gas reburning and early desorption after the start of reburning.

Further, according to the invention of claim 6 or 7, when the introduction from the downstream side and the introduction from the upstream side are switched, there is a shortage of air actually supplied to the exhaust gas recombustor. It is possible to continue stable combustion without causing any trouble.

[0023]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows the configuration of an embodiment of the present invention. In the intake passage 7 of the internal combustion engine 1, a throttle valve 4 is provided upstream of the collector 6, and an air flow meter 3 and an air cleaner 2 are provided upstream thereof. The opening of the throttle valve 4 is detected by the throttle valve opening sensor 5. Also, the intake valve 9
The fuel injection valve 8 is arranged so as to inject the fuel toward. Reference numeral 10 is a combustion chamber defined by the piston 11, 12 is a spark plug, and 13 is an exhaust valve.

The exhaust passage 14 of the internal combustion engine 1 is provided with a three-way catalyst device 23 in which a catalyst such as platinum is carried on a carrier made of ceramics or the like. A combustor 21 is provided. The exhaust gas recombustor 21 includes an ignition plug 22 as an ignition means. The ignition plug 22 is connected to an ignition device (not shown) composed of an ignition coil and the like, and spark discharge is performed by this ignition device. In this embodiment, the catalyst device 23 and the exhaust gas recombustor 21 are housed in the same casing. A temperature sensor 24 for detecting the internal temperature is arranged in the exhaust gas recombustor 21.

An HC adsorbent 18 housed in a casing different from that of the exhaust gas recombustor 21 is provided in the exhaust gas passage 14 on the upstream side of the exhaust gas recombustor 21. The HC adsorbent 18 is, for example, a honeycomb structure coated with an adsorbing component mainly composed of zeolite.
It has a property of adsorbing HC at a low temperature state of 00 to 200 ° C. and desorbing adsorbed HC at a temperature higher than that.

A secondary air pump 20 is provided as a secondary air supply device for supplying secondary air to the exhaust passage 14. The secondary air pump 20 has a pair of discharge passages 31 and 32, one passage 31 of which is the HC adsorbent 1
8 is in communication with the upstream air introducing portion 27 upstream, and the other passage 32 is in communication with the downstream air introducing portion 29 downstream of the HC adsorbent 18. The discharge passages 31 and 32 are provided with open / close valves 28 and 30 for opening and closing the discharge passages 31 and 32, respectively.

Further, 17 is a water temperature sensor for detecting the cooling water temperature of the internal combustion engine 1, 16 is an air-fuel ratio sensor arranged in the exhaust passage 14, 33 is an engine speed sensor, and these sensors are provided. Is detected by the air flow meter 3
It is input to the engine control unit (ECU) 26 together with detection signals from the throttle valve opening sensor 5 and the like.

The engine control unit 26 controls the fuel injection amount from the fuel injection valve 8 and the ignition timing by the ignition plug 12 based on the signals indicating the engine operating conditions, and the secondary air pump 20. The exhaust gas re-combustion is controlled by the ignition plug 22 and the like.

To explain the basic operation of the above exhaust gas purification device, when it is determined that the temperature inside the catalyst device 23 is below a predetermined temperature (for example, 300 ° C.) at the time of starting the internal combustion engine 1, the engine control unit 26 sends The signal increases the injection amount of the fuel injection valve 8 so that the air-fuel ratio becomes extremely rich (air-fuel ratio is 10 or less). at the same time,
The control signal from the engine control unit 26 activates the secondary air pump 20 and the spark plug 22 to start the supply of secondary air and spark discharge. The flow rate of the secondary air by the secondary air pump 20 is set to a flow rate that causes at least excess oxygen in the state of being mixed with the exhaust gas in the rich state. Since this varies depending on the displacement of the internal combustion engine 1 and the operating condition, it is set in advance by experiments so that the flow rate will be sufficient. Here, the initial introduction of the secondary air is performed from the downstream air introduction unit 29, and the upstream opening / closing valve 28 is closed.

As a result, the combustible component (H
C, CO, H ₂ ) and O ₂ from the secondary air are mixed and supplied to the downstream side, which is ignited by the spark of the spark plug 22 and burned in the exhaust gas recombustor 21. The heat of this exhaust gas re-combustion promotes the activation of the catalyst device 23. Here, since the exhaust gas passes through the HC adsorbent 18 before reaching the exhaust gas recombustor 21, the HC in the exhaust gas is adsorbed by the adsorbent 18 and removed in advance. Therefore, HC is prevented from being released into the atmosphere even during the period from the time of start-up until the exhaust gas reburner 21 actually reburns the exhaust gas. Since CO, H ₂ , and O ₂ burn in the exhaust gas recombustor 21, trapping HC does not hinder the exhaust gas reburning. Further, whether or not the exhaust gas recombustor 21 actually starts combustion is determined by a change in the temperature detected by the temperature sensor 24, and at the time when it is determined that combustion has started, the secondary air is introduced into the upstream air introduction portion. On-off valve 2 as done from 27
8 and 30 are switched.

The temperature of the HC adsorbent 18 rises due to the heating action due to the flow of the exhaust gas and the heat transmitted from the exhaust gas recombustor 21, and the H adsorbed with the temperature rises.
C comes to be desorbed, but at this stage, since the secondary air is supplied from the upstream side of the HC adsorbent 18 and passes through the inside of the adsorbent 18, the desorption of HC is promoted and the HC is adsorbed for a short period of time. Desorption is completed with. The desorbed HC is burned and purified in the exhaust gas recombustor 21 on the downstream side.

By the above-mentioned exhaust gas re-combustion, the catalyst device 23
When it is determined that the internal temperature has reached the predetermined temperature (for example, 350 ° C.) or higher, the discharge of the spark plug 22 and the secondary air pump 20 are stopped, and the exhaust gas re-combustion ends. At the same time, the fuel injection amount is controlled so that the air-fuel ratio becomes the stoichiometric air-fuel ratio in order to allow the three-way catalyst in the catalyst device 23 to act efficiently.

As described above, in this exhaust emission control device, HC discharged during the ignition delay period from the start of the internal combustion engine until the exhaust gas reburns is trapped to prevent it from being released into the atmosphere, and after ignition, , Desorb HC as soon as possible,
Since no influence is exerted on the air-fuel ratio control, the harmful components discharged during cold start are greatly reduced as a whole.

The above operation will be described more specifically with reference to the flowchart of FIG. This routine is repeatedly executed in the engine control unit 26, for example, at regular intervals. First, in step 1 (abbreviated as S1 in the figure), the cooling water temperature Tw, the intake air amount Qa, the engine speed Ne, the throttle valve opening TVO.
And the re-combustor temperature TE are read respectively. Next, in step 2, it is determined whether the cooling water temperature Tw is lower than the predetermined temperature TwL. If the temperature is lower than the predetermined temperature TwL, it is determined that the catalyst is inactive, and the routine proceeds to step 3 and subsequent steps to perform exhaust gas reburning. A catalyst temperature sensor that directly detects the temperature of the catalyst device 23 may be provided to determine whether the catalyst device 23 is active based on the detected temperature.

In step 3, the amount of fuel required for exhaust gas re-combustion is increased. For example, in order to make the air-fuel ratio richer than the stoichiometric air-fuel ratio, the fuel injection amount Tp is set as the target equivalent ratio TFBYA by using an increasing equivalent ratio TFEGI larger than 1.
To calculate. Then, the routine proceeds to step 4, where the secondary air amount required for exhaust gas re-combustion is set to the intake air amount Qa and the target equivalent ratio TF.
From BYA, Qa * (TFBYA-1) * C is calculated, and the secondary air supply amount by the secondary air pump 20 is controlled. Note that C is a constant. For reliable ignition and combustion, higher temperatures require higher concentrations of unburned components and oxygen, so the equivalence ratio TFEGI for increasing the amount is
As shown in FIG. 3, a larger value is given so that the air-fuel ratio becomes richer as the recombustor temperature TE becomes lower. Note that the increasing equivalence ratio TFEGI may be set according to the cooling water temperature Tw instead of the recombustor temperature TE.

Next, at step 5, the overlap time DTOV at the time of switching the secondary air introducing portion is determined. This is because the secondary air supplied from the upstream air introducing section 27 is
This corresponds to the time required to reach the downstream air introducing portion 29, and is set such that it becomes shorter in the higher speed range according to the rotation speed of the internal combustion engine, as shown in FIG.

In step 6, it is judged from the temperature TE whether combustion in the exhaust gas recombustor 21 has actually started. That is, compared with the predetermined temperature TEL, the predetermined temperature T
When EL or more, it is determined that combustion has started. If the temperature is lower than the predetermined temperature TEL, the combustion in the exhaust gas recombustor 21 has not started, so the routine proceeds to step 7, where the upstream side opening / closing valve 28 is closed and the downstream side opening / closing valve 30 is opened, and the downstream side air is opened. Secondary air is introduced from the introduction unit 29. In step 8, a counter DT for measuring the overlap time
To reset. Then, in step 9, the spark plug 2
2 is operated to reburn the exhaust gas reburner 21.

On the other hand, in step 6, if the temperature TE of the exhaust gas recombustor 21 is equal to or higher than the predetermined temperature TEL, it is determined that the combustion has started, the process proceeds to step 10, and the upstream side on-off valve 2
8 is opened, and the secondary air introduction from the upstream air introduction part 27 is started. Then, in step 11, it is determined whether the value of the counter DT exceeds the above-described overlap time DTOV. Until the value of the counter DT exceeds the overlap time DTOV, the secondary air is continuously introduced from both the downstream air introduction unit 29 and the upstream air introduction unit 27, and the value of the counter DT is sequentially increased in step 13. Increment. When the value of the counter DT exceeds the overlap time DTOV, the process proceeds from step 11 to step 12, the downstream side opening / closing valve 30 is closed, and 2 from the downstream side air introducing part 29.
Stop the next air introduction.

In this way, by introducing the secondary air from the upstream air introducing portion 27 at the time when the exhaust gas recombustor 21 actually starts combustion, desorption of HC from the HC adsorbent 18 is promoted. . Then, the desorbed HC flows into the exhaust gas recombustor 21 together with the secondary air, and is burned there.

When the cooling water temperature rises and becomes equal to or higher than the predetermined temperature TwL in step 2, it is judged that the catalyst has been activated, and the process proceeds to step 14, where the target equivalent ratio TFBYA is set to 1 corresponding to the stoichiometric air-fuel ratio. return. Then, in step 15, the secondary air pump 20 is stopped, and in step 16, both on-off valves 2
8 and 30 are closed, and this routine ends.

Next, a second embodiment will be described with reference to the flowchart of FIG. In consideration of the case where the combustion becomes unstable in the early stage of the start of combustion, the air introduction section is switched after confirming that the combustion is stabilized. This characteristic part is mainly in Step 10.
7, step 111 and step 112, and other steps 101 to 106 and step 1
08 to 110 and steps 113 to 119 are substantially the same as steps 1 to 6, steps 7 to 9 and steps 10 to 16 of the flowchart of FIG.

In this embodiment, when the exhaust gas recombustor 21 ignites and its temperature TE becomes equal to or higher than the predetermined temperature TEL, the routine proceeds from step 106 to step 111, and the value of the high temperature duration timer TTEH is incremented. If the temperature TE of the exhaust gas recombustor 21 is lower than the predetermined temperature TEL, the value of the timer TTEH is set to the value in step 107.
Is reset to 0. Then, in step 112,
It is determined whether or not the value of the timer TTEH exceeds a predetermined value TTEHL, and the process returns to step 108 without proceeding to step 113 until it exceeds the predetermined value TTEHL.

That is, unless the high temperature state of the exhaust gas re-combustor temperature TE continues for a predetermined time (TTEHL), the switching from the downstream air introducing portion 29 to the upstream air introducing portion 27 is not performed. Therefore, further destabilization of combustion due to frequent switching of the introduction position of the secondary air while combustion in the exhaust gas recombustor 21 is unstable is avoided.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing a mechanical structure of an exhaust emission control device according to the present invention.

FIG. 2 is a flowchart showing the contents of control of the present invention.

FIG. 3 Exhaust recombustor temperature TE and target fuel ratio TFEGI
The characteristic view showing the relationship with.

FIG. 4 is a characteristic diagram showing a relationship between an engine speed Ne and an overlap time DTOV.

FIG. 5 is a flowchart showing another embodiment of the present invention.

FIG. 6 is a characteristic diagram showing the relationship between the time required for desorption of HC and the flow rate of passing gas per unit time.

[Explanation of symbols]

1 ... Internal combustion engine 8 ... Fuel injection valve 14 ... Exhaust passage 18 ... HC adsorbent 20 ... Secondary air pump 21 ... Exhaust reburner 22 ... Spark plug 23 ... Catalyst device 26 ... Engine control unit 27 ... Upstream air introduction section 29 ... Downstream air inlet

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[Procedure amendment]

[Submission date] April 10, 2003 (2003.4.1)
0)

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0003

[Correction method] Change

[Correction content]

Therefore, in order to solve the above problem, an internal combustion engine
On the upstream side of the catalyst device arranged in the exhaust system of Seki,
Exhaust recombustor is installed, and the
Combustible exhaust gas is burned and touched by the combustion heat.
It is known that the medium is activated early (Patent Document 3
etc). This exhaust purification device injects fuel into the exhaust reburner
Not to increase the air-fuel ratio of the internal combustion engine,
Supply secondary air to combustible components and combustible air
Volatile exhaust gas is generated, and this flammable gas is burned with an ignition device.
It is burnt and has a very simple structure.
Early activation can be realized. Moreover, before catalytic activity
Also, HC and CO can be purified by combustion.
Therefore, it is a very effective means for cleaning exhaust gas as a whole.
It can be said that

[Patent Document 1] JP-A-8-238420

[Patent Document 2] Japanese Patent Publication No. 7-501117

[Patent Document 3] Japanese Patent Publication No. 6-508409

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction content]

That is, an exhaust gas purifying apparatus for an internal combustion engine according to a first aspect of the present invention is an exhaust gas reburner equipped with a catalyst device provided in an exhaust passage of the internal combustion engine, and an upstream side of the catalytic device and having an ignition means. An unburned component supply means for temporarily increasing the unburned component in the exhaust gas of the internal combustion engine for reburning in the exhaust gas recombustor, and the exhaust gas for reburning in the exhaust gas recombustor. 2 in the exhaust gas upstream of the reburner
In an exhaust gas purification device for an internal combustion engine, comprising: a secondary air supply device for supplying secondary air, H for adsorbing HC (hydrocarbon component) in exhaust gas on the upstream side of the exhaust gas recombustor.
C adsorbent is provided, and the secondary air introduction part by the secondary air supply device is arranged on the upstream side of the HC adsorbent, and the secondary air and exhaust gas introduced from the introduction part
Is configured so as to pass through the HC adsorbent .

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction content]

The unburned component supply means may be, for example, the third aspect.
As described above, the air-fuel ratio control means temporarily sets the air-fuel ratio of the internal combustion engine to the rich state.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0011

[Correction method] Change

[Correction content]

For ignition in the exhaust gas recombustor, CO,
If there is H ₂ and O ₂ is sufficient, even if HC has not been removed by the adsorbent, there is no problem in combustion in the exhaust re combustor.

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

[0012] As a side effect, by previously adsorbing HC, it is possible to slightly suppress the combustion temperature of the exhaust re combustor. That is, since only CO and H ₂ are combusted, the combustion temperature is lowered, for example, from about 950 ° C to about 750 ° C. Deterioration of the catalyst is generally promoted as the temperature rises, but particularly at 900 ° C. or higher, the catalyst exhibits a characteristic of rapid deterioration. If the combustion temperature can be lowered from about 950 ° C. to about 750 ° C. as described above, catalyst deterioration can be sufficiently suppressed and the overall exhaust performance can be improved over a long period of time. Especially, the activation temperature of the catalyst is about 300 ° C.
Since the temperature is around, it is possible to obtain a sufficient catalyst early activation effect even with the combustion gas at about 750 ° C.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction content]

Further, in the invention of claim 2 , the above H
C adsorbent is a honeycomb structure coated with adsorbent components
Secondary air and exhaust that is made up of the body and is introduced from the above-mentioned introduction part
All of the gas passes through this honeycomb structure.

[Procedure Amendment 8]

[Document name to be amended] Statement

[Name of item to be corrected] 0015

[Correction method] Change

[Correction content]

Further, in the invention of claim 4, the above H
Also on the downstream side of the C adsorbent, the secondary air supply device 2
A secondary air inlet is provided, which can be changed depending on the conditions.
The introduction of air from the future is controlled and the introduction on the upstream side
All of the secondary air and exhaust gas introduced from the
It is designed to pass through the adsorbent.

[Procedure Amendment 9]

[Document name to be amended] Statement

[Correction target item name] 0016

[Correction method] Change

[Correction content]

For example , during the combustion delay period in the exhaust gas recombustor, by introducing the secondary air from the downstream side of the HC adsorbent, only the exhaust gas flows through the HC adsorbent, HC can be efficiently adsorbed on the HC adsorbent. After the combustion of the exhaust gas recombustor is started, 2
By introducing secondary air from the upstream side of the HC adsorbent,
The elimination of HC can be promoted.

[Procedure Amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0017

[Correction method] Change

[Correction content]

According to the invention of claim 5 , the exhaust gas flow of the internal combustion engine is
A catalytic device installed in the path and located upstream of this catalytic device
And an exhaust gas reburner equipped with an ignition means,
Arranged so that exhaust gas always passes upstream of the combustor
And adsorbs HC (hydrocarbon components) in the exhaust gas
When the HC adsorbent and the above catalytic device need to be heated,
Note that the air-fuel ratio of the internal combustion engine should
Similarly to the air-fuel ratio control means for temporarily setting the rich state,
The air-fuel ratio control means described above is used for re-combustion in the air re-combustor.
Operating at the same time as the enrichment of the air-fuel ratio
Secondary air that supplies secondary air into the exhaust gas on the flow side
After the start of combustion in the exhaust gas recombustor
Is to introduce secondary air from the upstream side of the above HC adsorbent
Is characterized by.

[Procedure Amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0018

[Correction method] Delete

[Procedure Amendment 12]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Delete

[Procedure Amendment 13]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Delete

[Procedure Amendment 14]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Delete

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F01N 3/24 F01N 3/30 C F02D 41/04 305A 3/30 45/00 360C F02D 41/04 305 B01D 53/36 103B 45/00 360 ZAB (72) Inventor Kazuhiko Kaneri 2 Takaracho, Kanagawa-ku, Yokohama, Kanagawa Nissan Motor Co., Ltd. (72) Hirofumi Tsuchida 2 Takaracho, Kanagawa-ku, Yokohama, Nissan Nissan Motor Co., Ltd. F term (reference) 3G084 BA13 BA24 BA25 CA02 DA10 EA11 EB12 EC03 FA07 FA10 FA20 FA27 FA29 3G091 AA02 AA17 AB03 AB10 BA15 CA01 CA23 CA26 CB02 DA02 DB10 DB11 DC03 EA05 EA07 EA16 EA17 EA34 FA04 HA20G HAB HAO HA02 GB06 GA02 HA06B02 HA06 HA02B06 HA02B06 HA02B06 HA02B06 HA02B06 HA02B06 HA02B06 HA02B06A02 JA26 KA05 LB02 MA01 NA08 ND02 NE01 NE13 PA01Z PA11Z PD02Z PD12Z PE08Z 4D048 AA06 AA13 AA18 AB05 A C06 CC43 CC61 CD01 CD08 CD10 DA01 DA08 DA20

Claims (7)

[Claims] 1. A catalytic device provided in an exhaust passage of an internal combustion engine, an exhaust gas recombustor located upstream of the catalytic device and provided with ignition means, and for recombustion in the exhaust gas recombustor. In addition to the unburned component supply means for temporarily increasing the unburned component in the exhaust gas of the internal combustion engine, and also for secondary combustion in the exhaust gas recombustor, secondary to the exhaust gas upstream of the exhaust gas recombustor. In an exhaust gas purification device for an internal combustion engine, comprising: a secondary air supply device that supplies air, an HC adsorbent that adsorbs HC (hydrocarbon component) in exhaust gas is provided upstream of the exhaust gas recombustor. And the secondary air introduction part by the secondary air supply device is the H
An exhaust gas purification device for an internal combustion engine, wherein the exhaust gas purification device is arranged upstream of the C adsorbent. 2. The exhaust gas purifying apparatus for an internal combustion engine according to claim 1, wherein the unburned component supply means comprises air-fuel ratio control means for temporarily making the air-fuel ratio of the internal combustion engine rich. 3. The secondary air introduction section of the secondary air supply device is provided on both the upstream side and the downstream side of the HC adsorbent, and the introduction of air from each is controlled according to the conditions. The exhaust emission control device for an internal combustion engine according to claim 1 or 2, characterized in that: 4. A means for detecting the start of combustion of the exhaust gas recombustor, and the secondary air is introduced from a downstream introduction part before the start of combustion, and the secondary air is introduced from the upstream introduction part after the start of combustion. The exhaust gas purification apparatus for an internal combustion engine according to claim 3, further comprising: a secondary air control unit that introduces 5. The exhaust gas purifying apparatus for an internal combustion engine according to claim 4, wherein the exhaust gas recombustor is provided with a temperature sensor, and the start of combustion is detected from the temperature of the exhaust gas recombustor. 6. The stop of secondary air from the downstream introduction part and the 2 from the upstream introduction part due to the start of combustion of the exhaust gas recombustor.
The exhaust emission control device for an internal combustion engine according to claim 4 or 5, wherein an appropriate overlap period is provided between the start of introduction of the next air and the start of introduction of the next air. 7. The exhaust gas purifying apparatus for an internal combustion engine according to claim 6, wherein the overlap time, which is the overlap period, is set so as to become shorter on the high speed side in accordance with the engine speed.