JP2003106185A - Poisoned catalyst restoring system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a poisoned catalyst restoring system capable of surely restoring poisoned catalyst while preventing thermal deterioration of the catalyst. SOLUTION: This system is provided with an exhaust gas heat quantity increasing means increasing exhaust gas heat quantity by increasingly controlling intake air quantity according to catalyst temperature information from a catalyst temperature detecting means when the catalytic converter is poisoned and restore of the catalytic converter is required.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst poisoning / regenerating apparatus, and more particularly, to a technology for reliably regenerating a poisoned catalyst by preventing thermal deterioration of the catalyst due to excessive temperature rise.

[0002]

2. Related Background Art A catalytic converter is installed in an exhaust passage of an internal combustion engine mounted on a vehicle, and the catalytic converter causes harmful substances (HC, CO, N) in exhaust gas to be present.
Ox) is purified. By the way, the fuel contains poisoning components such as S (sulfa) component (sulfur component), and the catalytic converter may be poisoned by the S component. For example, in the case of a palladium (Pd) -based catalyst, the S component is adsorbed on palladium to reduce the active sites, and in the case of a NOx storage catalyst, barium (Bd)
The S component is adsorbed on the NOx storage material such as a) and the storage sites are reduced.

When the catalytic converter is poisoned in this manner, it is known that the catalyst converter can be regenerated by removing the poisoning component, that is, the S component, etc. by heating the catalyst to a high temperature state. There is. Known means for bringing the catalyst into a high temperature state include an ignition timing retarding technique and a two-stage combustion technique for injecting fuel during an expansion stroke or an exhaust stroke in a cylinder injection engine.

[0004]

However, in the case of the ignition timing retarding technique, there is a limit to the temperature rise of the catalyst, and it is not possible to raise the temperature of the catalyst significantly during low load operation. There is a problem that it cannot be removed sufficiently. Further, in the case of the two-stage combustion technique, since the reaction on the catalyst is large, there is a problem that the catalyst may be excessively heated and may be damaged due to thermal deterioration depending on operating conditions.
In particular, when the pre-stage catalytic converter is provided near the internal combustion engine together with the post-stage catalytic converter, if the two-stage combustion is performed to regenerate the post-stage catalytic converter, most of the unburned components due to the secondary injection are in the pre-stage catalytic converter. This problem is prominent because the internal reaction occurs and the temperature of the front-stage catalyst rises excessively.

The present invention has been made to solve the above problems, and an object of the present invention is to reliably regenerate a poisoned catalyst while preventing thermal deterioration of the catalyst. To provide a device.

[0006]

In order to achieve the above object, according to the invention of claim 1, a catalytic converter provided in an exhaust passage of an internal combustion engine mounted on a vehicle for purifying harmful substances in exhaust gas is provided. , Catalyst temperature detecting means for detecting the catalyst temperature of the catalytic converter, intake air amount adjusting means for adjusting the intake air amount to the internal combustion engine, and regeneration of the catalytic converter due to poisoning of the catalytic converter is required. At this time, the intake air amount adjusting means controls the increase of the intake air amount according to the catalyst temperature information from the catalyst temperature detecting means,
An exhaust heat quantity increasing means for increasing the exhaust heat quantity is provided.

Therefore, when the catalytic converter is poisoned by the S component or the like and it becomes necessary to regenerate the catalytic converter, the intake air amount is increased by the exhaust heat amount increasing means, and the combustion heat amount generated in the combustion chamber of the internal combustion engine is reduced. As the exhaust gas temperature rises, the exhaust gas temperature rise rate increases, and the catalytic converter heats up to a high temperature at which regeneration is possible early and reliably. In this case, 2
Unlike the staged combustion technology, unburned components do not react in the catalytic converter, so only the catalytic converter does not suddenly heat up, and the catalytic converter is thermally deteriorated and damaged due to excessive temperature rise. Is avoided.

Particularly, depending on the catalyst temperature, for example, when the catalyst temperature is low, the intake air amount is increased to increase the exhaust gas temperature raising rate, and when the catalyst temperature is high to some extent, the intake air amount is increased to a small limit. Since the exhaust gas temperature raising rate is suppressed, even if the catalyst temperature is low, the catalyst converter will quickly rise to a high temperature at which it can be regenerated. On the other hand, if the catalyst temperature is relatively high, It is more reliably prevented that the catalytic converter is thermally deteriorated and damaged due to excessive temperature rise.

Preferably, the intake air amount is controlled to be increased, and the supplied fuel amount is controlled to be increased in accordance with the intake air amount and the operating condition of the internal combustion engine to enhance combustion. The temperature is raised to a high temperature that can be regenerated. Further, according to the invention of claim 2, further provided is an exhaust flow control means provided in an exhaust passage of the internal combustion engine for controlling exhaust flow, and the exhaust flow control means increases the exhaust heat amount by the exhaust heat amount increasing means. At this time, the exhaust flow is suppressed so that the exhaust pressure rises.

Therefore, when the exhaust heat amount is increased by the exhaust heat amount increasing means, the exhaust flow control means simultaneously suppresses the exhaust flow so that the exhaust pressure rises. At this time, the exhaust gas is a compressible fluid. As a result, the exhaust gas having an increased amount of heat is compressed and stays in the exhaust system at a high density, and the reaction in the exhaust system is promoted. As a result, the exhaust gas temperature rises rapidly, and the catalytic converter rises to a high temperature at which regeneration is possible earlier.

Further, the invention of claim 3 is characterized in that the exhaust flow control means suppresses the exhaust flow in accordance with the catalyst temperature information from the catalyst temperature detection means.
That is, depending on the catalyst temperature, for example, when the catalyst temperature is low, the degree of suppression of exhaust flow is increased to increase the exhaust gas temperature rising rate, and when the catalyst temperature is high to some extent, the degree of suppression of exhaust flow is limited to a small degree and exhaust gas rises. The temperature rate is suppressed.

Therefore, even when the catalyst temperature is low,
The catalytic converter will quickly reach a high temperature that can be regenerated. On the other hand, when the catalyst temperature is relatively high, it is possible to more reliably prevent the catalytic converter from being damaged by heat due to excessive temperature rise. To be done. Further, according to the invention of claim 4, it further comprises an ignition timing control means for controlling the ignition timing of the internal combustion engine, and the ignition timing control means delays the ignition timing when the exhaust heat amount increasing means increases the exhaust heat amount. It is characterized by making it horn.

Therefore, when the exhaust heat amount is increased by the exhaust heat amount increasing means, at the same time, the ignition timing is retarded (ignition timing retard) and the combustion becomes slow, and the unburned components discharged from the combustion chamber are exhausted in the exhaust system. It reacts well and generates heat. As a result, the exhaust gas temperature rises more rapidly, and the catalytic converter rises to a reproducible high temperature even earlier.

Further, the invention of claim 5 is characterized in that the ignition timing control means delays the ignition timing in accordance with the catalyst temperature information from the catalyst temperature detecting means.
That is, depending on the catalyst temperature, for example, when the catalyst temperature is low, the ignition timing retard amount is increased to increase the exhaust gas temperature raising rate, and when the catalyst temperature is high to some extent, the ignition timing retard amount is limited to a small value. The exhaust gas temperature raising rate is suppressed.

Therefore, even when the catalyst temperature is low,
The catalytic converter will quickly reach a high temperature that can be regenerated. On the other hand, when the catalyst temperature is relatively high, it is possible to more reliably prevent the catalytic converter from being damaged by heat due to excessive temperature rise. To be done.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. Referring to FIG. 1, there is shown a schematic configuration diagram of a catalyst poisoning regeneration device according to the present invention, and the configuration of the catalyst poisoning regeneration device will be described below. As shown in FIG. 1, an engine body (hereinafter, simply referred to as an engine) 1 which is an internal combustion engine has a fuel injection in an intake stroke (intake stroke injection) and a fuel injection in a compression stroke (intake stroke injection) by switching a fuel injection mode. A cylinder injection type spark ignition type gasoline engine capable of performing compression stroke injection is adopted. This in-cylinder injection type engine 1 can be easily operated at a stoichiometric air-fuel ratio (Stoichio) or at a rich air-fuel ratio (rich air-fuel ratio operation), or at a lean air-fuel ratio (lean air-fuel ratio operation). Is feasible.

As shown in the figure, the cylinder head 2 of the engine 1 is provided with an electromagnetic fuel injection valve 6 together with a spark plug 4 for each cylinder, whereby fuel is directly injected into the combustion chamber. It is possible. An ignition coil 8 that outputs a high voltage is connected to the spark plug 4. A fuel supply device (not shown) having a fuel tank is connected to the fuel injection valve 6 via a fuel pipe 7. More specifically, the fuel supply device is provided with a low-pressure fuel pump and a high-pressure fuel pump, which supplies the fuel in the fuel tank to the fuel injection valve 6 at a low fuel pressure or a high fuel pressure. Can be injected from the fuel injection valve 6 toward the combustion chamber at a desired fuel pressure.

An intake port is formed in the cylinder head 2 in a substantially upright direction for each cylinder, and one end of an intake manifold 10 is connected so as to communicate with each intake port. The intake manifold 10 is provided with an electromagnetic throttle valve (intake air amount adjusting means) 14 for adjusting the intake air amount and a throttle position sensor (TPS) 16 for detecting an opening degree θth of the throttle valve 14.

Further, the cylinder head 2 is formed with an exhaust port in a substantially horizontal direction for each cylinder, and one end of an exhaust manifold 12 is connected so as to communicate with each exhaust port. As the exhaust manifold 12, a dual type exhaust manifold system is adopted here. Others, exhaust manifold 12
May be a single type exhaust manifold system or a clamshell type exhaust manifold system.

Although not shown, the engine 1 concerned
Is also configured for exhaust gas recirculation (EGR). Since the in-cylinder injection type engine 1 is already known, the detailed description of its configuration will be omitted. An exhaust pipe (exhaust passage) 20 is connected to the exhaust manifold 12, and the exhaust pipe 20 is located near the exhaust manifold 12 as an exhaust purification catalyst device (catalyst converter) and has a front stage three-way catalyst (FCC) 22. Is located under the floor of the vehicle and is located under the floor catalyst unit (UCC)
30 is interposed.

The underfloor catalyst unit 30 is composed of an occlusion type NOx catalyst 32 and a post-stage three-way catalyst 34, which are arranged in this order from the upstream side. The storage type NOx catalyst 32 stores the NOx component in the exhaust gas when the exhaust air-fuel ratio is the lean air-fuel ratio, and when the exhaust air-fuel ratio is the theoretical air-fuel ratio or a rich air-fuel ratio on the rich side of the stoichiometric air-fuel ratio, the storage is performed. It is a catalyst having the property of releasing the generated NOx component.

The front stage three-way catalyst 22 and the rear stage three-way catalyst 34 are
Copper (Cu), cobalt (C) as an active noble metal on the carrier
o), silver (Ag), platinum (Pt), rhodium (Rh),
Composed of any of palladium (Pd), H
It is an oxidation catalyst configured to oxidize and remove C and CO.
In addition, these occlusion type NOx catalyst 32 and the front stage three-way catalyst 22
The configuration, function, and the like of the latter-stage three-way catalyst 34 are publicly known, and the description thereof is omitted here.

Further, as shown in the figure, an O ₂ sensor 22 is provided in the exhaust pipe 20, and an occlusion type NOx catalyst 32 is provided.
A high temperature sensor 36 for detecting the temperature of the storage type NOx catalyst 32 is provided in the. Further, an exhaust flow control valve 40 is provided in a portion of the exhaust pipe 20 downstream of the underfloor catalyst unit 30.

The exhaust flow control valve 40 promotes reduction of harmful substances (including unburned substances such as HC and CO as well as NOx, smoke and H ₂ ) by suppressing the exhaust flow. Therefore, it is possible to change at least one of the exhaust pressure, the exhaust density, and the exhaust flow velocity (reduction effect enhancing factor). Although various methods are conceivable as the exhaust flow control valve 40, here, for example, a closed state is shown in FIG.
As shown in the valve open state in (b), a butterfly valve 42 that can adjust the flow passage area of the exhaust pipe 20 by rotating the valve body 44 around a shaft 43 that penetrates the exhaust pipe 20 is adopted.
An actuator 45 is provided in the butterfly valve 42, and the butterfly valve 42 is opened and closed by rotating the valve body 44 around the shaft 43 by the actuator 45.

The ECU 60 includes an input / output device and a storage device (R
OM, RAM, non-volatile RAM, etc., central processing unit (C
PU), a timer counter, etc.
With 0, comprehensive control of the catalyst poisoning regeneration device including the engine 1 is performed. On the input side of the ECU 60, the above-mentioned throttle position sensor 16, O ₂ sensor 22,
Various sensors such as the high temperature sensor 36 are connected, and the detection information from these sensors is input.

On the other hand, the output side of the ECU 60 is connected to various output devices such as the fuel injection valve 6, the ignition coil 8, the throttle valve 14, the actuator 45, etc.
The fuel injection amount, the fuel injection timing, the ignition timing, the exhaust flow control amount, etc., which are calculated based on the detection information from the various sensors, are output to these various output devices. Fuel is injected at an appropriate timing, spark ignition is performed by the ignition plug 4 at an appropriate timing, and the throttle valve 1 is attached at an appropriate timing.
4. The butterfly valve 42 is opened and closed.

The operation of the catalyst poisoning / regenerating apparatus according to the present invention thus constructed will be described below. Referring to FIG. 3, a control routine of the catalyst poisoning regeneration control according to the present invention is shown in a flow chart, which will be described below with reference to FIG. It should be noted that poisoning components such as S component are easily adsorbed to the storage-type NOx catalyst 32, the regeneration frequency of the storage-type NOx catalyst 32 is high, and the storage-type NOx catalyst 32 has a higher heat-resistant temperature than the three-way catalyst. Since it is low, the storage type NOx is used here.
The regeneration control of the catalyst 32 will be described as an example.

First, in step S10, it is determined whether or not the poisoning regeneration condition is satisfied. Here, for example, the poisoning component such as the S component increases substantially in proportion to the cumulative traveling distance of the vehicle. Therefore, by determining whether or not the cumulative traveling distance reaches a predetermined traveling distance, the poisoning regeneration condition is determined. It is determined that is established. When the determination result is true (Yes) and it is determined that the poisoning regeneration condition is satisfied, the occlusion type NOx catalyst 3
In No. 2, it can be determined that reproduction is necessary, and in this case, the process proceeds to step S12.

In step S12, the throttle valve 14 is operated to the valve opening side to increase the intake air amount (exhaust heat amount increasing means). Specifically, the intake air amount, that is, the opening degree of the throttle valve 14 is the temperature of the storage NOx catalyst 32 detected by the high temperature sensor 36, that is, the catalyst temperature and the operating state of the engine 1 (engine rotation speed, volume efficiency, net average). It is set according to the effective pressure, exhaust temperature, etc. (intake air amount =
f (catalyst temperature, operating state)). Actually, as shown in FIG. 4, a map showing the relationship between the catalyst temperature and the intake air amount is preset, and the intake air amount, that is, the throttle valve 14 is set.
The opening degree of is read from the map, and the map value is further corrected according to the operating state of the engine 1.

As described above, when the amount of intake air is increased when the storage type NOx catalyst 32 needs to be regenerated, sufficient oxygen is supplied into the combustion chamber to promote the combustion reaction and increase the amount of heat generation. As a result, the occlusion type NOx catalyst 32 reaches a high temperature (which depends on the catalyst, for example, 750 ° C.) that can be regenerated at an early stage due to the increase in the temperature rising rate.

Since the intake air amount is set according to the catalyst temperature, when the catalyst temperature is low, the intake air amount is increased to secure a sufficient heat generation amount, and the occlusion type NOx catalyst 32 is regenerated early. When the temperature reaches a possible high temperature, while the catalyst temperature is relatively high, the intake air amount is reduced and the heat generation amount is suppressed, so that the occlusion type NOx catalyst 32 is prevented from being thermally deteriorated due to excessive temperature rise.

In step S12, the amount of fuel supplied is increased at the same time. Specifically, the supply fuel amount is set according to the intake air amount, that is, the opening degree of the throttle valve 14 and the operating state of the engine 1 (engine rotation speed, volume efficiency, net mean effective pressure, exhaust temperature, etc.) (supply Fuel amount = f
(Operating state)). As a result, the combustion reaction in the combustion chamber is further promoted and the calorific value is increased.
The x-catalyst 32 will reach a reproducible high temperature earlier due to the increase in the heating rate.

In step S14, the exhaust flow control valve 4
0, that is, the butterfly valve 42 is operated to the valve closing side to suppress the exhaust flow (exhaust flow control means). Specifically, the valve opening of the butterfly valve 42 is also set according to the temperature of the occlusion type NOx catalyst 32, that is, the catalyst temperature (valve opening = f
(Catalyst temperature)). Actually, as shown in FIG. 5, a map showing the relationship between the catalyst temperature and the exhaust flow control valve opening is set in advance, and the opening of the exhaust flow control valve 40, that is, the butterfly valve 42 is the map. Read from. further,
The valve opening of the butterfly valve 42 may be corrected according to the operating state of the engine 1 (engine rotation speed, volume efficiency, net average effective pressure, exhaust temperature, etc.).

As described above, when the intake air amount is increased and the exhaust gas flow is suppressed, since the exhaust gas is a compressible fluid, the exhaust gas heated to a high temperature and compressed to a high temperature is compressed. It will stay in the exhaust system at a high density, and the reaction in the exhaust system will be promoted. This allows
The temperature rise rate of the occlusion type NOx catalyst 32 is accelerated, and the occlusion type Nx
The Ox catalyst 32 is a high temperature (eg, 7
Up to 50 ° C).

Further, since the valve opening degree of the butterfly valve 42, that is, the degree of suppression of exhaust flow is set according to the catalyst temperature, when the catalyst temperature is low, the exhaust flow is reduced as in the case of the intake air amount. The degree of suppression is large and a sufficient amount of heat generation is secured, and the occlusion type NOx catalyst 32 reaches a high temperature at which regeneration is possible at an early stage. On the other hand, when the temperature of the catalyst is relatively high, the degree of suppression of exhaust flow is reduced and the amount of heat generation is increased. Is suppressed, and the storage type NOx catalyst 32 is prevented from being thermally deteriorated due to excessive temperature rise.

In step S16, the ignition timing is retarded (ignition timing control means). Specifically, the retard amount of the ignition timing (retard amount) is also set according to the temperature of the occlusion type NOx catalyst 32, that is, the catalyst temperature (retard amount = f (catalyst temperature)). Actually, as shown in FIG. 6, a map showing the relationship between the catalyst temperature and the ignition timing retard amount is preset, and the ignition timing is read from the map. Furthermore, the ignition timing retard amount may be corrected according to the operating state of the engine 1 (engine rotation speed, volumetric efficiency, net average effective pressure, exhaust temperature, etc.).

As described above, when the intake air amount is increased, the exhaust flow is suppressed, and the ignition timing is retarded, the combustion becomes slow and the unburned components of the fuel discharged from the combustion chamber are exhausted. It reacts well with excess oxygen in the system to generate heat. Thereby, the storage type NOx catalyst 32
The temperature rising rate is further accelerated, and the occlusion type NOx catalyst 32 rapidly reaches a high temperature (for example, 750 ° C.) at which it can be regenerated.

Since the retard amount of the ignition timing is set according to the catalyst temperature, the retard amount is set when the catalyst temperature is low, as in the case of the intake air amount and the exhaust flow control valve opening. Large and sufficient reaction in the exhaust system is secured, and storage type NO
When the x-catalyst 32 rapidly reaches a high temperature at which it can be regenerated, on the other hand, when the catalyst temperature is relatively high, the retard angle amount is reduced, the reaction in the exhaust system is suppressed, and the storage-type NOx catalyst 32 is overheated Thermal deterioration is prevented.

Although not shown, a predetermined time for which removal of poisoning components can be considered to be completed is set in advance by experiments or the like, and the increase of the intake air amount, the suppression of exhaust flow and the retard of ignition timing are as follows. It is performed until the predetermined time passes. Then, when the removal of the poisoning component is completed, the integrated traveling distance is reset. When the cumulative traveling distance is reset, the determination result of step S10 becomes false (No), and in this case, the process proceeds to step S20.

In step S20, the increase of the intake air amount is canceled, the increase of the supplied fuel amount is canceled, and the control of the intake air amount and the supplied fuel amount is returned to the normal control. Further, in step S22, the exhaust flow control valve 40, that is, the butterfly valve 42 is opened, and the suppression of exhaust flow is stopped. Then, in step S24, the retard of the ignition timing is stopped, and the control of the ignition timing is returned to the normal control.

Although the description is finished above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the catalyst temperature is directly detected by the high temperature sensor 36, but the operating state of the engine 1 (engine speed, volumetric efficiency, net average effective pressure, exhaust temperature, intake air amount, manifold pressure, Exhaust flow rate, exhaust pressure, elapsed time, etc.)
The catalyst temperature may be estimated based on

In the above embodiment, the ignition timing is retarded in addition to the increase of the intake air amount and the exhaust flow. However, only the intake air amount is increased, or the intake air amount and the exhaust gas are increased. Sufficient effect can be obtained by only suppressing the flow. Further, in the above-mentioned embodiment, the cylinder injection type gasoline engine is used as the engine 1, but the engine 1 may be an intake pipe injection type engine.

Further, when the exhaust flow is suppressed, the intake air amount, the ignition timing, the EG
The R amount or the like may be adjusted, or the gear ratio of the transmission (not shown) may be changed to the higher gear side to increase the engine rotation speed. Further, in the above embodiment, although the combustion air-fuel ratio and the exhaust air-fuel ratio are not particularly mentioned, in order to perform the catalyst regeneration more efficiently, the intake air amount is increased, the exhaust flow is suppressed, and the ignition timing is delayed. When performing the corner, it is preferable to control the exhaust air-fuel ratio to be the stoichiometric air-fuel ratio or the rich air-fuel ratio.

Further, in the above embodiment, the front stage three-way catalyst (FCC) 22 is provided. However, in this case, the temperature of the catalyst is raised early in the cold state, and the exhaust purification function of the three-way catalyst is rapidly exhibited. This is because the front stage three-way catalyst (FCC) 22 is not necessarily provided as long as the exhaust gas purification function of the underfloor catalyst unit (UCC) 30 can be secured in the cold state.

[0045]

As described in detail above, according to the catalyst poisoning / regenerating apparatus of claim 1 of the present invention, when the catalytic converter is poisoned by the S component and the like, it becomes necessary to regenerate the catalytic converter. Since the intake air amount is controlled to be increased by the exhaust heat amount increasing means, it is possible to increase the combustion heat amount generated in the combustion chamber of the internal combustion engine to increase the exhaust temperature raising rate, and the catalytic converter is thermally deteriorated due to excessive temperature rise and damaged. It is possible to quickly raise the temperature of the catalytic converter to a reproducible high temperature while avoiding the occurrence.

In particular, since the intake air amount is controlled to increase according to the catalyst temperature information from the catalyst temperature detecting means, even if the catalyst temperature is low, the temperature of the catalytic converter can be quickly raised to a high temperature at which it can be regenerated. On the other hand, when the catalyst temperature is relatively high, it is possible to more reliably prevent the catalytic converter from being thermally deteriorated and damaged due to excessive temperature rise.

According to the catalyst poisoning regeneration device of the second aspect, when the exhaust heat amount increasing means increases the exhaust heat amount, the exhaust flow control means simultaneously suppresses the exhaust flow, so that the exhaust gas with the increased heat amount is exhausted. Can be compressed and accumulated in the exhaust system at a high density to accelerate the reaction in the exhaust system, so that the exhaust temperature can be raised rapidly and the catalytic converter can be regenerated to a high temperature that can be regenerated earlier. The temperature can be raised.

Further, according to the catalyst poisoning regeneration device of the third aspect, the exhaust gas flow is suppressed according to the catalyst temperature information from the catalyst temperature detecting means, so that even when the catalyst temperature is low. It is possible to raise the temperature of the catalytic converter to a reproducible high temperature at an early stage. On the other hand, when the catalyst temperature is relatively high, it is more certain that the catalytic converter will be thermally deteriorated and damaged due to excessive temperature rise. Can be prevented.

Further, according to the catalyst poisoning regeneration device of the fourth aspect, when the exhaust heat amount is increased by the exhaust heat amount increasing means, the ignition timing is retarded at the same time (ignition timing retard). The unburned components discharged from the exhaust gas can react well in the exhaust system to raise the exhaust temperature more rapidly, and the catalytic converter can be raised to a reproducible high temperature even earlier.

Further, according to the catalyst poisoning regeneration device of the fifth aspect, the ignition timing is retarded according to the catalyst temperature information from the catalyst temperature detecting means, so that even when the catalyst temperature is low. It is possible to raise the temperature of the catalytic converter to a reproducible high temperature at an early stage. On the other hand, when the catalyst temperature is relatively high, it is more certain that the catalytic converter will be thermally deteriorated and damaged due to excessive temperature rise. Can be prevented.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a catalyst poisoning regeneration device according to the present invention.

FIG. 2 is a diagram showing a butterfly valve as an exhaust flow control valve.

FIG. 3 is a flowchart showing a control routine of catalyst poisoning regeneration control according to the present invention.

FIG. 4 is a map showing the relationship between catalyst temperature and intake air amount.

FIG. 5 is a map showing the relationship between catalyst temperature and exhaust flow control valve opening.

FIG. 6 is a map showing the relationship between catalyst temperature and ignition timing retard amount.

[Explanation of symbols]

1 engine body 6 Fuel injection valve 12 Exhaust manifold 14 Throttle valve (intake air amount adjusting means) 20 exhaust pipe 22 First stage three-way catalyst (FCC) 30 Underfloor catalytic unit (UCC) 32 Storage type NOx catalyst 34 Second-stage three-way catalyst 36 High temperature sensor (catalyst temperature detection means) 40 Exhaust flow control valve 42 butterfly valve 60 ECU (electronic control unit)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02D 45/00 312 F02D 45/00 312R 3G301 F02P 5/15 F02P 5/15 Z F term (reference) 3G004 AA01 BA06 DA21 DA24 EA01 3G022 AA06 DA02 GA00 GA08 GA10 3G065 AA04 CA12 DA07 FA03 GA00 GA08 GA41 3G084 AA04 BA05 BA09 BA17 BA24 DA10 EA11 EB08 EC03 FA10 FA27 FA29 3G091 AA02 A07 A01 02 HA08 HA12 3G301 HA01 HA04 HA15 JA25 JA33 LA03 LB04 LC01 MA11 NC02 ND02 NE01 PA11A PD02A PD12Z PE01Z

Claims (5)

[Claims] 1. A catalytic converter provided in an exhaust passage of an internal combustion engine mounted on a vehicle, for purifying harmful substances in exhaust gas, catalyst temperature detecting means for detecting a catalyst temperature of the catalytic converter, and an internal combustion engine Intake air amount adjusting means for adjusting the intake air amount, and the intake air amount adjusting means according to the catalyst temperature information from the catalyst temperature detecting means when the catalytic converter is poisoned and regeneration of the catalytic converter is required. An exhaust gas calorie increasing means for increasing the exhaust gas heat quantity by controlling the intake air quantity to be increased by the means. 2. An exhaust gas flow control means for controlling exhaust gas flow, which is provided in an exhaust passage of an internal combustion engine, wherein the exhaust gas flow control means increases the exhaust gas pressure when the exhaust gas heat amount increasing means increases the exhaust gas heat amount. 2. The catalyst poisoning regeneration device according to claim 1, wherein exhaust gas flow is suppressed so as to rise. 3. The catalyst poisoning regeneration device according to claim 2, wherein the exhaust flow control means controls the exhaust flow according to the catalyst temperature information from the catalyst temperature detection means. 4. An ignition timing control means for controlling the ignition timing of the internal combustion engine, wherein the ignition timing control means delays the ignition timing when the exhaust heat amount increasing means increases the exhaust heat amount. The catalyst poisoning regeneration device according to any one of claims 1 to 3, which is characterized. 5. The catalyst poisoning regeneration device according to claim 4, wherein the ignition timing control means retards the ignition timing in accordance with the catalyst temperature information from the catalyst temperature detection means.