JPH06212959A - Exhaust emission control device of internal combustion engine - Google Patents

Abstract

(57) [Summary] [Purpose] To quickly warm up the catalyst without deteriorating exhaust emissions. [Structure] An electric heater catalyst (EHC) 10 and a main catalyst 11 are provided in series in an exhaust system. A fuel injection injector 4 is provided in the intake system. The electric air pump 1 is provided on the upstream side of the EHC 10 through an air control valve 25 opened and closed by a negative pressure switching valve (VSV) 27 and an air pipe 20.
Secondary air is supplied from 9. When the ECU 41 determines that the upstream side EHC 10 has been warmed up while the secondary air is being supplied, the ECU 41 further increases the amount of fuel required to warm up the catalyst from the amount of fuel required to maintain engine rotation. The increased fuel amount is obtained, and the injector 4 is driven to supply the increased fuel amount to the engine body 1. Therefore, the large amount of unburned components obtained by the increased fuel amount and the heat generation of the EHC 10 are combined, and the warm-up of the main catalyst 11 is promoted.
Further, the amount of unburned components does not increase more than necessary before the completion of warming up the EHC 10.

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 purifying exhaust gas discharged from an internal combustion engine.

[0002]

2. Description of the Related Art Conventionally, as this type of technique, for example, an "engine exhaust gas purification device" disclosed in Japanese Patent Laid-Open No. 61-58912 is known. With this exhaust purification system,
A technique has been proposed for promptly increasing the purifying ability of an exhaust gas purifying catalyst in an exhaust passage when the engine has a high load.

That is, in order to promptly purify the exhaust gas by the catalyst when the engine has a high load, it is necessary to quickly raise the temperature of the catalyst when the load changes from a low load to a high load. That is, it is necessary to quickly warm up the catalyst. Therefore, in this exhaust emission control device, the amount of fuel injected from the fuel injection valve to the intake passage is increased in order to increase the amount of unburned components in the exhaust gas when the engine load exceeds the set value. The concentration of the air-fuel mixture is increased, and the secondary air is supplied from the secondary air supply device to the exhaust passage on the upstream side of the catalyst. By this control, the reaction of the catalyst is promptly activated and the catalyst is quickly warmed up. Moreover, it is known that the temperature rise of the catalyst becomes faster as the amount of unburned components in the exhaust gas increases. Therefore, the predetermined amount of unburned components required for the catalyst to rise to a specific temperature is taken into consideration, and the concentration of the air-fuel mixture is increased only until the amount of unburned components reaches the required amount according to the engine load. . In other words, the concentration of the air-fuel mixture is increased until the integrated value of the throttle opening after the throttle valve is opened reaches a certain set value, and then the secondary air is supplied. There is.

[0004]

However, in the above-mentioned conventional exhaust gas purification device, in order to quickly warm up the catalyst, the air-fuel mixture is mixed before the secondary air is supplied to the upstream side of the catalyst. The concentration is increased. Where the concentration is high,
That is, the rich air-fuel mixture is used for reaction activation of the catalyst only after the secondary air is supplied, and contributes to warm-up of the catalyst. Therefore, especially in the cold state, the rich air-fuel mixture supplied before the catalyst is warmed up is exhausted from the exhaust passage without being used to activate the reaction of the catalyst. There was a problem that was worse.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an exhaust gas purification apparatus for an internal combustion engine which makes it possible to quickly warm up a catalyst without deteriorating exhaust emission. To provide.

[0006]

In order to achieve the above object, in the first aspect of the present invention as set forth in claim 1, as shown in FIG. 1, the exhaust system M2 of the internal combustion engine M1 is arranged in series. A plurality of catalysts M3a and M3b, a fuel supply means M4 for supplying fuel to the internal combustion engine M1, and a plurality of catalysts M3
Drive control of the secondary air supply means M5 for supplying secondary air to the exhaust system M2 from the upstream of a and M3b, and the fuel supply means M4 and the secondary air supply means M5 during cold operation of the internal combustion engine M1. Drive control means M6 for
A thermal energy increasing means M7 for increasing the thermal energy to be carried to the catalysts M3a, M3b together with the exhaust gas discharged from the internal combustion engine M1 to the exhaust system M2; Catalyst M3a, M3b
Of these, the activation determination means M8 for determining that the upstream catalyst M3a has been activated, and when the activation determination means M8 determines that the upstream catalyst M3a has been activated,
The second drive control means M9 for driving and controlling the thermal energy increasing means M7 is provided during the supply of the secondary air by the secondary air supply means M5.

Similarly, in order to achieve the above object, in the second aspect of the present invention, as shown in FIG. 2, a plurality of catalysts arranged in series in the exhaust system M2 of the internal combustion engine M1. M3a, M3b, fuel supply means M4 for supplying fuel to the internal combustion engine M1, and a plurality of catalysts M3a, M3
During the cold operation of the secondary air supply means M5 for supplying secondary air from the upstream of b to the exhaust system M2, and the internal combustion engine M1,
Amount of fuel for calculating a first amount of fuel required for the internal combustion engine M1 to maintain rotation and a second amount of fuel required for obtaining the amount of heat required for warming up the catalysts M3a, M3b Before the upstream catalyst M3a of the plurality of catalysts M3a and M3b is warmed up during the cold operation of the calculation means M10 and the internal combustion engine M1, the fuel supply means M4 is driven based on the first fuel amount, During the cold operation, after the upstream catalyst M3a has been warmed up and during the supply of the secondary air by the secondary air supply means M5, the fuel is added based on the sum of the first fuel amount and the second fuel amount. It is intended to include a fuel supply means control device M11 for driving the supply means M4.

[0008]

According to the structure of the first invention, as shown in FIG. 1, during the cold operation of the internal combustion engine M1, the first drive control means M6 causes the fuel supply means M4 and the secondary air supply means M5. Are each driven and controlled. By this control,
Fuel is appropriately supplied to the internal combustion engine M1, and secondary air is appropriately supplied to the plurality of catalysts M3a and M3b of the exhaust system M2. At this time, since the upstream catalyst M3a receives the exhaust heat of the internal combustion engine M1 before the plurality of catalysts M3a and M3b are activated, the catalyst M3a is activated earlier than the other catalysts M3b. Will be realized. Then, the activation determination means M8 determines the activation of the upstream side catalyst M3a.

When the activation determining means M8 determines that the upstream side catalyst M3a is activated, the second drive control means M9 heats the secondary air while the secondary air supply means M5 is supplying the secondary air. The energy increasing means M7 is drive-controlled. By this control, the exhaust system M2 from the internal combustion engine M1
The thermal energy to be carried to the plurality of catalysts M3a, M3b is increased together with the exhaust gas discharged to the. Here, the heat energy may be the exhaust heat itself or may be the unburned component of the fuel contained in the exhaust. After activation of the upstream side catalyst M3a, activation of each of the catalysts M3a and M3b is promoted by the amount of heat energy carried along with the exhaust gas. In addition, since sufficient oxygen is also supplied to the catalysts M3a and M3b by the secondary air, the upstream catalyst M3a
The heat of reaction accelerates the activation of the downstream side catalyst M3b.

Therefore, before the activation of the upstream side catalyst M3a, the thermal energy to be carried to the catalysts M3a and M3b together with the exhaust gas is not increased, so that the deterioration of the exhaust gas emission can be suppressed accordingly.

According to the structure of the second aspect of the invention, as shown in FIG. 2, the fuel amount calculation means M10 is necessary for maintaining the rotation of the internal combustion engine M1 during cold operation of the internal combustion engine M1. The first fuel amount and the second fuel amount required to obtain the heat amount required for warming up the catalysts M3a and M3b are calculated. Then, during the cold operation, the plurality of catalysts M3a, M3b
Before the upstream side catalyst M3a is warmed up, the fuel supply means control unit M11 drives the fuel supply means M4 based on the first fuel amount. By this control, the internal combustion engine M
1 is supplied with fuel, but only the amount of fuel necessary for its rotation is supplied, so that deterioration of exhaust emission is reduced. In this case, the upstream side catalyst M3a that receives the exhaust heat of the internal combustion engine M1 first is warmed up first.

On the other hand, during the cold operation of the internal combustion engine M1, after the upstream side catalyst M3a has been warmed up, and the secondary air supply means M5 is used.
During the supply of the secondary air by the fuel supply means control device M
11, the fuel supply means M4 is driven based on the sum of the first fuel amount and the second fuel amount. By this control, the internal combustion engine M1 is supplied with a fuel amount that is further increased from the fuel amount required to maintain its rotation, and the amount of unburned components sent to the catalysts M3a, M3b together with the exhaust amount is increased by the increased amount. Will be increased. In addition, since sufficient oxygen is also supplied to the catalysts M3a and M3b by the secondary air, the reaction heat of the upstream catalyst M3a promotes warm-up of the downstream catalyst M3b. Here, since the fuel amount is increased after the upstream side catalyst M3a has been warmed up, the unburned component is the upstream side catalyst M3.
The deterioration of exhaust emission is reduced by reacting at a.

[0013]

【Example】

(First Embodiment) A first embodiment in which the exhaust gas purifying apparatus for an internal combustion engine according to the first and second inventions is embodied in a gasoline engine system for an automobile will be described in detail with reference to FIGS. 3 to 7.

FIG. 3 is a schematic diagram showing the gasoline engine system in this embodiment. An intake manifold 2 and an exhaust manifold 3 are connected to an engine body 1 that constitutes an in-line gasoline engine as an internal combustion engine. The intake manifold 2 constitutes a part of an intake system, and introduces air taken from the outside through an intake pipe (not shown) into the combustion chamber of the engine body 1. A throttle valve (not shown) is provided in the middle of the intake pipe. An injector 4 for injecting fuel is provided near the intake manifold 2. In this example,
The injector 4 constitutes a heat energy increasing means and a fuel supply means. As is well known, the injector 4 is opened by energization to inject the fuel sent from a fuel tank (not shown) through a fuel pump into the vicinity of the intake port. Then, the fuel injected from the injector 4 becomes an air-fuel mixture and is introduced into the combustion chamber. In the combustion chamber of the engine body 1,
The introduced air-fuel mixture is exploded and burned by the operation of a spark plug (not shown). On the other hand, the exhaust manifold 3 constitutes a part of the exhaust system and guides the exhaust gas after combustion from the combustion chamber. The exhaust manifold 3 is provided with a plurality of exhaust pipes 5, 6, in order to discharge the discharged exhaust gas into the atmosphere.
7 and the like are connected, and first and second three-way catalytic converters 8 and 9 are connected in the middle of the exhaust pipes 5 to 7, respectively. As is well known, these first and second three-way catalytic converters 8 and 9 are used to convert hydrocarbons (H
This is for purifying exhaust gas by oxidizing C) and carbon monoxide (CO) and reducing nitrogen oxide (NOx).

The first three-way catalytic converter 8 located on the upstream side of the exhaust system has a built-in three-way catalyst divided into large and small. Of these two three-way catalysts, the smaller one on the upstream side is the catalyst 10 with an electric heater equipped with an electric heater, and the larger one on the downstream side is the main catalyst 11. The catalyst 10 with an electric heater has an electrode arranged at the center of a honeycomb core that forms a metal catalyst by attaching a three-way catalyst, and heats its own metal catalyst by energizing between the center electrode and the hub. It is designed to let you. Further, the main catalyst 11 is simply composed of a metal catalyst to which a three-way catalyst is attached. The catalyst 10 with an electric heater is arranged on the upstream side of the main catalyst 11 and is mainly operated when the engine is cold started. On the other hand, the second three-way catalytic converter 9 has one main catalyst 12 built therein, and the main catalyst 12 is composed of a metal catalyst to which a three-way catalyst is attached in the same manner as described above.

The engine body 1 of this embodiment is provided with a starter 13 for imparting a rotational force to a crankshaft (not shown) by cranking when the engine body 1 is started. Further, the starter 13 is provided with a starter switch 31 for detecting its on / off operation. As is well known, the starter 13 is connected to the ignition switch 14 and is turned on / off by operating the switch 14. The ignition switch 14 can be switched to OFF position ON, ON position ON, and starter position ST by key operation. And the ignition switch 1
While No. 4 is switched to the starter position ST via the ON position ON, the starter 13 is turned on and the starter switch 31 outputs the starter signal STS of "ON".

In order to energize the catalyst 10 with an electric heater,
The center electrode side of the catalyst 10 with an electric heater is connected to a plus electrode 16a of a vehicle-mounted battery 16 via a power line 15 and an ignition switch 14. The rib side of the catalyst 10 with an electric heater is connected to the negative electrode 16b of the battery 16 via the power supply line 17.
Further, a first relay switch 18 is provided in the middle of the power supply line 15 in order to control energization from the battery 16 to the catalyst 10 with an electric heater. Then, the ignition switch 14 is switched to the ON position ON, and the first relay switch 18 is turned “on” by the electric signal, whereby the power supply line 15 is closed, and the battery 16 is connected to the catalyst 10 with the electric heater. Energization is performed from. Further, by turning off the first relay switch 18, the power supply line 15 is opened, and the energization from the battery 16 to the catalyst 10 with an electric heater is stopped.

The first catalytic converter 8 is provided with a catalyst temperature sensor 32 for detecting the temperature (catalyst temperature) THC of the catalyst 10 with an electric heater. Further, in the first catalytic converter 8, on the upstream side of the catalyst temperature sensor 32,
An oxygen sensor 33 for detecting the oxygen concentration OX in the exhaust gas is provided.

Next, the structure of the secondary air supply means for supplying the secondary air to the exhaust system will be described. In this embodiment, an electric air pump 19 driven by energization is provided to supply secondary air to the exhaust system.
The electric air pump 19 has a built-in electric motor, and when driven, sucks and discharges outside air. An end of an air pipe 20 for supplying secondary air is connected to the discharge port of the electric air pump 19, and the other end of the pipe 20 is connected to the exhaust pipe 5 upstream of the first catalytic converter 8. . Battery 16 to electric air pump 19
The positive terminal of the pump 19 is connected to the positive electrode 16a of the battery 16 via the power lines 21 and 15 and the ignition switch 14 in order to energize the battery.
The negative terminal of the electric air pump 19 is connected to the negative electrode 16 of the battery 16 via the power lines 22 and 17.
connected to b. Further, a second relay switch 23 is provided in the middle of the power supply line 21 to control the energization of the electric air pump 19. Then, the ignition switch 14 is switched to the ON position ON, and the second relay switch 23 is turned “on” by an electric signal, so that the power supply line 21 is closed and the battery 16 with respect to the electric air pump 19 is closed. Is energized. When the electric air pump 19 is driven by the energization, the sucked outside air can be introduced into the exhaust system from the upstream side of the first catalytic converter 8 as secondary air through the air pipe 20. or,
By turning off the second relay switch 23, the power supply line 21 is closed and the electric air pump 19 is closed.
The power supply from the battery 16 to the is stopped.

In the above electric circuit, the power supply line 15
The first relay switch 1 between the power line 21 and the power line 21.
A resistor 24 is connected to start the electric air pump 19 at a low voltage when the switch 8 is turned on.

On the other hand, in the middle of the air pipe 20, a diaphragm type air control valve 25 for opening and closing the pipe 20 is provided. The air control valve 25 includes a diaphragm chamber 25b partitioned by a diaphragm 25a, and a valve body 25c for opening and closing the air pipe 20 is fixed to the diaphragm 25a. The diaphragm chamber 25b is provided with a spring 25d that urges the diaphragm 25a downward, and the urging force of the spring 25d causes the valve body 2 to move.
5c is biased to a valve closing position that closes the middle of the air pipe 20. On the other hand, the valve body 25c is connected to the air pipe 20.
One end of a vacuum pipe 26 is connected to the diaphragm chamber 25b so that the diaphragm chamber 25b is located at a valve opening position where the valve is opened halfway. The other end of the vacuum pipe 26 is connected to the intake manifold 2. Then, the intake negative pressure generated in the intake manifold 2 can be introduced into the diaphragm chamber 25b through the vacuum pipe 26. Further, in order to control the introduction of the negative pressure into the diaphragm chamber 25b, a vacuum switching valve of three types (hereinafter simply referred to as "VSV") 27 which is opened and closed by an electric signal is provided in the middle of the vacuum pipe 26.
Is provided. When the VSV 27 is turned “on” by an electric signal, the middle of the vacuum pipe 26 is opened. As a result, negative pressure is allowed to be introduced into the diaphragm chamber 25b of the air control valve 25, the valve body 25c is arranged at the valve opening position against the biasing force of the spring 25d, and the air pipe 20 is opened midway. On the other hand, when the VSV 27 is turned “off” by not energizing, the vacuum pipe 26 is closed midway and the diaphragm chamber 25b is opened to the atmosphere. As a result, atmospheric pressure is introduced into the diaphragm chamber 25b,
The valve body 25c is arranged at the valve closing position by the urging force of the spring 25d, and the air pipe 20 is closed midway.

A check valve 28 is provided in the middle of the air pipe 20. This check valve 28
This is to prevent exhaust gas from flowing back from the exhaust pipe 5 to the air pipe 20 due to exhaust pulsation.

In addition, the engine body 1 is provided with a water temperature sensor 34 for detecting the temperature (cooling water temperature) THW of the cooling water. The engine body 1 is provided with a rotation speed sensor 35 for detecting the engine rotation speed NE. The intake pipe on the upstream side of the intake manifold 2 has an intake flow rate Q taken into the combustion chamber of the engine body 1.
An air flow meter 36 for detecting In this embodiment, the water temperature sensor 34, the rotation speed sensor 35, the air flow meter 36, and the like detect parameters corresponding to the operating state of the engine.

In this embodiment, the injector 4, the catalyst 10 with the electric heater, the electric air pump 19 and the VSV 27 are used.
Is controlled by an electronic control unit (hereinafter simply referred to as “ECU”) 41. Therefore, the ECU 4
An injector 4, first and second relay switches 18 and 23, and a VSV 27 are electrically connected to 1. The ECU 41 has a starter switch 31,
Catalyst temperature sensor 32, oxygen sensor 33, water temperature sensor 34,
The rotation speed sensor 35 and the air flow meter 36 are electrically connected to each other. Then, the ECU 41 executes various calculation and determination processes based on various signals from the starter switch 31, the sensors 32 to 35, and the air flow meter 36. Accordingly, the injector 4, the first and second relay switches 18 and 23, and the VSV 27 are suitably driven and controlled.

FIG. 4 is a block diagram showing the electrical construction of the ECU 41. ECU 41 is a central processing unit (CPU)
42, a read-only memory (ROM) 43 in which a predetermined control program and the like are stored in advance, and a random access memory (RAM) 4 in which the calculation results of the CPU 42 are temporarily stored
4. Backup RA that saves pre-stored data
Equipped with M45 etc. Then, the ECU 41 includes the respective units 42 to 45, the external input circuit 46, and the external output circuit 47.
And the like are connected as a logical operation circuit by a bus 48. The CPU 42 of this embodiment also has the function of a free running counter.

The external input circuit 46 is connected to the starter switch 31, the sensors 32 to 35, the air flow meter 36, and the like described above. Further, the injector 4, the first and second relay switches 18 and 23, the VSV 27, and the like described above are connected to the external output circuit 47, respectively. Then, the CPU 42 uses the starter switch 31, the sensors 32 to 35, and the air flow meter 36.
Various signals from the etc. are read as input values via the external input circuit 46. Further, the CPU 42 suitably drives and controls the injector 4, the first and second relay switches 18 and 23, the VSV 27 and the like via the external output circuit 47 based on these input values.

In this embodiment, the ECU 41 controls the first drive control means, the activation determination means, the second drive control means,
A fuel amount calculation means and a fuel supply means control device are configured. When the engine is cold started, the ECU
Reference numeral 41 operates the catalyst 10 with an electric heater based on various signals from the starter switch 31, the catalyst temperature sensor 32, the water temperature sensor 34, etc., and then drives the electric air pump 19. Further, the ECU 41 drives the injector 4 to control the fuel injection at the time of starting. Furthermore, the ECU 4
1 executes engine air-fuel ratio feedback control (FB control) based on a signal from the oxygen sensor 33.

Next, in the gasoline engine system configured as described above, the ECU 4 is activated when the engine is started.
The processing content for the exhaust gas purification control executed by No. 1 will be described.

The flowchart of FIG. 5 shows a "secondary air supply control routine" executed by the ECU 41, and the operation of the ignition switch 14 switches the starter signal STS from the starter switch 31 from "OFF" to "ON". It starts at the timing.

That is, first, at step 101, the starter signal STS from the starter switch 31 is "ON".
It is determined whether or not has been switched from "OFF" to "OFF". Here, when the starter signal STS is not switched from "ON" to "OFF", it is determined that the starter 13 is performing the cranking, and the subsequent processing is temporarily terminated. On the other hand, the starter signal STS changes from "on" to "off".
If the engine has been switched to, it is determined that the engine has been completely cranked by the starter 13, and the process proceeds to step 102.

In step 102, the value of the catalyst temperature THC is read based on the signal from the catalyst temperature sensor 32. Subsequently, in step 103, it is determined whether or not the value of the catalyst temperature THC has reached a predetermined activation temperature value β. Here, when the value of the catalyst temperature THC has already reached the activation temperature value β, the catalyst with electric heater 10
Assuming that the temperature is sufficiently warm, the subsequent processing is temporarily terminated. If the value of the catalyst temperature THC has not reached the activation temperature value β, the catalyst with electric heater 10
The process proceeds to step 104 to heat the.

Then, in step 104, the first
The relay switch 18 is turned on to start energization of the catalyst 16 with the electric heater from the battery 16. As a result, the catalyst 10 with the electric heater starts heating itself. Further, when the first relay switch 18 is turned “on”, the electric air pump 19 starts to be started at a low voltage through the resistor 24.

Next, in step 105, the CPU 4
The free running counter in 2 starts counting the value of the elapsed time T1 after the start of energization of the catalyst 10 with an electric heater.

Subsequently, at step 106, the value of the catalyst temperature THC is read based on the signal from the catalyst temperature sensor 32. Then, in step 107, the catalyst temperature T
It is determined whether the value of HC has reached the activation temperature value β.
Here, if the value of the catalyst temperature THC has not reached the activation temperature value β, the process jumps to step 106 to read the value of the catalyst temperature THC, and in step 107, the value of the catalyst temperature THC is changed to the activation temperature. It is determined whether or not the value β has been reached. That is, it waits until the value of the catalyst temperature THC reaches the activation temperature value β. On the other hand, step 10
7, when the value of the catalyst temperature THC reaches the activation temperature value β, it is assumed that the catalyst with electric heater 10 has reached the temperature effective for exhaust gas purification by heating the catalyst with electric heater 10. Move to 108.

In step 108, the second relay switch 23 is turned "on" to start energization of the battery 16 to the electric air pump 19. That is, the electric air pump 19 is preliminarily driven before starting the supply of the secondary air.

Then, in step 109, the CPU
Another free running counter at 42 starts counting the value of the elapsed time T2 after the start of energization of the electric air pump 19. Further, in step 110, the process waits until the value of the elapsed time T2 reaches the reference time value A sufficient for pre-driving the electric air pump 19. Then, when the value of the elapsed time T2 reaches the reference time value A, the VSV 27 is turned “on” in step 111.

As a result, the air control valve 25
Negative pressure is introduced into the diaphragm chamber 25b of the valve body 25c
Is placed in the valve opening position and the air pipe 20 is opened.
At this time, since the electric air pump 19 has already been preliminarily driven, the outside air discharged from the pump 19 is
Secondary air begins to be supplied from the upstream side of the first three-way catalytic converter 8 to the exhaust system through the air pipe 20.

In step 112, the CPU 42
VSV2 by another free running counter in
The counting of the value of the elapsed time T3 after 7 is turned on is started.

Next, in step 113, the value of the elapsed time T1 which started counting first is the catalyst 1 with the electric heater.
Wait until the reference time value B for ending the energization to 0 is reached. Then, when the value of the elapsed time T1 reaches the reference time value B, it is determined that the warm-up of the catalyst 10 with the electric heater is completed, and in step 114, the first relay switch 18 is turned off, The electricity supply from the battery 16 to the catalyst 10 with the electric heater is terminated. As a result, the heating of the catalyst 10 with the electric heater is stopped.

Further, in step 115, the catalyst energization completion flag XFEHC indicating that the energization of the catalyst 10 with the electric heater after the completion of warming up is completed is set to "1". Further, in step 116, it waits until the value of the elapsed time T3 after the VSV 27 is turned on reaches the predetermined reference time value C. Then, when the value of the elapsed time T3 reaches the reference time value C, in step 117, the second relay switch 18 is turned off, and the energization from the battery 16 to the electric air pump 19 is terminated. At the same time, the VSV 27 is turned “off”.

As a result, the electric air pump 19 is stopped. Further, the diaphragm chamber 25b of the air control valve 25 is opened to the atmosphere by the VSV 27, and the valve body 2
6c is arranged at the valve closing position and the middle of the air pipe 20 is closed. As a result, the supply of secondary air to the exhaust system is stopped.

After the processing of step 117 is finished, the processing of this "secondary air supply control routine" is finished, and the processing operation of the secondary air supply control at the cold start of the engine is finished.

Subsequently, when starting the engine, the ECU 4
The processing contents of the fuel injection control at the time of start executed by the procedure No. 1 will be described. The flowchart of FIG. 6 shows the “start-up fuel injection control routine” executed by the ECU 41,
It is started at the timing when the ignition switch 14 is switched to the ON position ON.

When this process is started, first step 2
01, the cooling water temperature T based on the detected values of the water temperature sensor 34, the rotation speed sensor 35, the air flow meter 36,
Values such as HW, engine speed NE, and intake air flow rate Q are read. At the same time, the catalyst energization end flag XFEHC set in the "secondary air supply control routine" is read.

Then, in step 202, the target value of the fuel injection amount at start-up f0 is calculated based on the values of the cooling water temperature THW, the engine speed NE, the intake air flow rate Q and the like. The value of the fuel injection amount f0 at the time of starting is obtained according to a predetermined calculation formula, and corresponds to the minimum amount of fuel necessary for enabling the engine start and rotation at the time of starting the engine.

Next, at step 203, it is judged if the catalyst energization completion flag XFEHC is "1". Here, if the catalyst energization end flag XFEHC is not "1", in step 204, step 20
The injection process is executed according to the value of the fuel injection amount f0 at start-up obtained in 2. That is, the fuel is injected into the intake manifold 2 by driving and controlling the injector 4 based on the value of the fuel injection amount f0 at startup.

After that, in step 205, it is judged whether or not the value of the cooling water temperature THW read in step 201 is larger than a predetermined warm-up completion temperature value α. Then, when the value of the cooling water temperature THW is not larger than the warm-up completion temperature value α, it is determined that the warm-up of the engine body 1 is not completed, and the routine jumps to step 201,
The processing from step 201 is repeated. On the other hand, when the value of the cooling water temperature THW is larger than the warm-up completion temperature value α,
Assuming that the engine main body 1 has been warmed up, the process proceeds to step 209.

On the other hand, in step 203, when the catalyst energization completion flag XFEHC is "1",
Assuming that the catalyst 10 with the electric heater has been warmed up, the routine proceeds to step 206, and the value of the fuel injection amount f0 at the time of starting obtained at step 202 is corrected by the correction coefficient K (0 <K <
The fuel injection amount is increased by 1) and set as a new fuel injection amount at start-up f0. Here, the correction coefficient K is a value corresponding to the fuel increase amount required to generate at least the fuel required to warm up the main catalyst 11 of the main catalyst 11 and the main catalyst 12. The correction coefficient K is a value such as "0.1", and in this case, step 20
The fuel injection amount f0 at start-up obtained in 2 is increased by "10%".

In step 207, step 2
The injection process is executed according to the value of the fuel injection amount f0 at the time of starting obtained in 06. That is, the increased starting fuel injection amount f
By controlling the drive of the injector 4 based on the value of 0, fuel is injected into the intake manifold 2.

After that, from step 207 to step 20
8, the process determines whether or not the value of the cooling water temperature THW read in step 201 is larger than the predetermined warm-up completion temperature value α. Then, if the value of the cooling water temperature THW is not larger than the warm-up completion temperature value α, it is determined that the warm-up of the engine body 1 has not been completed, and step 2
Jump to 01 and repeat the processing from step 201. On the other hand, when the value of the cooling water temperature THW is larger than the warm-up completion temperature value α, it is determined that the warm-up of the engine body 1 is completed, and the process proceeds to step 209.

Then, step 205 or step 20.
In step 209 after shifting from 8, the processing of engine air-fuel ratio feedback control (FB control) is executed based on the signal from the oxygen sensor 32 and the like. Further, in step 210, the catalyst energization end flag XFEHC is cleared to "0", and the subsequent processing is ended.

As described above, the startup fuel injection control process corresponding to the secondary air supply control process at startup is executed. Here, the operations of the secondary air supply control and the fuel injection control at the time of starting will be described with reference to the time chart of FIG. 7. In this time chart, the starter signal STS, the operation of the catalyst 10 with the electric heater, the operation of the electric air pump 19, and the VS when the engine is cold started are shown.
The operation of V27 and the change in the air-fuel ratio on the upstream side of the catalyst 10 with the electric heater are shown. Also, changes in the catalyst temperature THC, the temperature of the main catalyst 11, the cooling water temperature THW, and the exhaust emission corresponding to these changes are shown.

Now, at time t0, the ignition switch 14 is turned on, and at time t1, when the starter signal STS switches from "on" to "off" with the operation of the ignition switch 14, the catalyst 10 with an electric heater is activated. It is turned "on" by energization to start its heating. At this time, the value of the catalyst temperature THC begins to rise as shown by the solid line. Further, the air-fuel ratio as shown by the solid line is obtained according to the value of the minimum fuel injection amount f0 at the time of starting the engine.

Thereafter, at time t2, the catalyst temperature TH
When the value of C reaches the activation temperature value β, the electric air pump 19 is turned on and started. Next, at a time t3, a reference time value A which is a time T2 elapsed from the time t2, that is, a time after the electric air pump 19 is started.
VSV27 is turned "on". Then, at the timing when the VSV 27 is turned “on”, the supply of the secondary air to the exhaust system is started. Therefore, the catalyst 10 with the electric heater is supplied with oxygen by the secondary air in a state where the catalyst 10 with the electric heater itself reaches the activation temperature value β, so that the temperature of the catalyst 10 with the electric heater gradually rises. .

At time t4, when the elapsed time T1 from the time t1, that is, the time from the start of heating the catalyst 10 with an electric heater reaches the reference time value B, the catalyst 10 with an electric heater is warmed up. The same catalyst 10
Is turned off and heating is stopped. Then, at this point, the value of the fuel injection amount f0 at startup is switched from the minimum fuel amount required for starting the engine to the fuel amount increased by the amount required for warming up the main catalyst 11 and the like. ,
According to the switching, the air-fuel ratio becomes rich as shown by the solid line. Further, when the air-fuel ratio is switched to rich, the amount of unburned components in the exhaust gas is increased accordingly. At this point, the catalyst 10 with the electric heater has already been warmed up, and since the oxygen necessary for the catalytic reaction is sufficiently present by the secondary air, the heating of the catalyst 10 with the electric heater is stopped. Even if it is done, it does not hinder the subsequent exhaust gas purification action by the catalyst 10. In addition, the large amount of unburned components in the exhaust gas and the oxygen in the secondary air cause the catalyst 10 with an electric heater.
Due to the heat generated by the reaction with the exhaust gas and the heat of the exhaust gas, the activation reaction of the main catalyst 11 located on the downstream side of the catalyst 10 with an electric heater is promoted. Therefore, the temperature rise of the main catalyst 11 is further increased, and the main catalyst 11 is quickly warmed up. As the main catalyst 11 is quickly warmed up, the exhaust emission discharged from the exhaust system to the outside becomes good as shown by the solid line. Here, FIG.
Regarding the changes of the air-fuel ratio, the catalyst temperature THC, the temperature of the main catalyst 11 and the exhaust emission from time t4, the case of the present embodiment in which the starting fuel injection amount f0 is increased is shown by a solid line. The case where the fuel injection amount f0 at startup is not increased is shown by the broken line.

After that, at time t5, when the elapsed time T3 from time t3, that is, the time after the VSV 27 is turned on reaches the reference time value C, the VSV 27 is turned off. Then, at time t6, when the air-fuel ratio feedback control (FB control) of the engine is started,
Each of the electric air pump 19 and the VSV 27 is turned off, and the supply of the secondary air to the exhaust system is stopped.

Further, in this embodiment, at the time t1, the starter signal STS is switched from "ON" to "OFF", and at the same time, the fuel injection amount at start-up f0 does not start to be increased, but the catalyst 10 with the electric heater is activated. At time t4 when the warm-up is completed, the fuel injection amount f0 at startup is increased. Therefore, in the conventional example, 2 is set between time t0 and time t4.
As shown by the dotted line, the air-fuel ratio becomes rich and the exhaust emission deteriorates significantly, whereas in the present embodiment, as shown by the solid line, the deterioration of exhaust emission during that time is suppressed.

As described above, in this embodiment, when the secondary air is supplied to the exhaust system at the cold start of the engine, it is judged that the upstream side catalyst 10 with the electric heater has been warmed up. For the first time, the value of the starting fuel injection amount f0 is increased and corrected by a predetermined amount, and the injector 4 is drive-controlled based on the value of the injection amount f0. For this reason,
The engine is supplied with a fuel amount that is further increased from the minimum required fuel amount for starting the engine, and the amount of unburned components sent to the catalyst 10 with the electric heater and the main catalyst 11 together with the exhaust gas is increased by the increased amount. It That is, the engine body 1
The thermal energy to be carried to the catalyst with electric heater 10 and the main catalyst 11 is increased together with the exhaust gas discharged from the exhaust system to the exhaust system.

Therefore, in addition to the heat of the exhaust gas itself,
The reaction heat generated from the upstream side electric heater-equipped catalyst 10 and the increased amount of the unburned component are combined, and the downstream side main catalyst 1
The activation of No. 1 is promoted, and the warm-up of the main catalyst 11 is promoted. Moreover, here, after the warm-up of the catalyst 10 with the electric heater is completed, the fuel injection amount f0 at the start time is increased, so that more fuel than necessary is supplied to the engine until the catalyst 10 with the electric heater warms up. There is no supply to the main body 1 and the amount of unburned components discharged from the engine main body 1 does not increase more than necessary. As a result, in this embodiment, it is possible to quickly warm up the catalyst 10 with the electric heater, the main catalyst 11, etc. without deteriorating the exhaust emission.

In addition, in this embodiment, the sequence of energizing the catalyst 10 with an electric heater and the electric air pump 19 is controlled at the time of cold start of the engine, and the electric air pump 20 is operated after the catalyst 10 with an electric heater is operated. To be done. Therefore, the catalyst with electric heater 10 and the electric air pump 19 are not operated at the same time, and the both 10, 19 are not energized at the same time.

Therefore, in this embodiment, unlike the case where both the catalyst with electric heater and the electric air pump are simultaneously operated, the heated catalyst with electric heater 10 is activated before reaching the activation temperature value β. It is not cooled by the next air. As a result, the temperature of the catalyst 10 with an electric heater can be raised more quickly, and the exhaust gas can be purified faster by the catalyst 10 with an electric heater. That is, when the engine is cold started, the exhaust gas purification performance of the catalyst 10 with the electric heater can be further improved. Further, since the catalyst with electric heater 10 and the electric air pump 19 are not energized at the same time, a large load is not applied to the battery 16. That is, a large inrush current is required to start the electric air pump 19, but the catalyst 10 with the electric heater is connected to the electric air pump 1.
Since the battery is not energized at the same time as 9, the load applied to the battery 16 instantaneously is reduced. Therefore, the battery 16
The voltage of will not drop too much. As a result, the battery 16 is not forced to consume a large amount of power instantaneously, and the battery 1 caused by the instantaneous consumption of a large amount of power is
The deterioration of No. 6 can be prevented in advance. In addition, since it is possible to prevent the voltage of the battery 16 from being drastically lowered or deteriorated, there is no fear that the rotation of the engine will be disturbed due to the change in the voltage level of the battery 16.

(Second Embodiment) A second embodiment in which the exhaust purification system for an internal combustion engine according to the first invention is embodied in a gasoline engine system for an automobile will be described below with reference to FIGS. 8 to 10. In this embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. The different points will be mainly described.

FIG. 8 shows a part of the intake pipe 51 connected to the intake manifold 2 described above. A throttle valve 52 is provided in the middle of the intake pipe 51. In this embodiment, a bypass passage 53 that bypasses the throttle valve 52 and connects the upstream side and the downstream side of the valve 52 is provided in the middle of the intake pipe 51. In the middle of the bypass passage 53, when the engine is idling when the throttle valve 52 is fully closed, a linear solenoid idle speed control valve (I) for adjusting the intake flow rate Q to stabilize the idling is provided.
SCV) 54 is provided. And this ISCV
The opening degree of the bypass passage 53 is adjusted by driving 54 according to a predetermined control signal from the ECU 41. In this embodiment, the bypass passage 53 and the ISCV5
4 constitutes a heat energy increasing means.

Therefore, when the engine is idling, I
By controlling the opening degree of the SCV 54 and its opening timing, the amount of air flowing through the bypass passage 53 is adjusted,
The intake air flow rate Q to be supplied to the combustion chamber of the engine body 1 is controlled. Then, the intake flow rate is increased to some extent by the ISCV 54, so that the engine speed NE at the time of idling is increased, that is, the fast idle state is set. The warm-up of the engine body 1 is promoted, and the amount of exhaust gas discharged from the engine body 1 to the exhaust manifold 3 is increased. That is, the thermal energy accompanying the exhaust gas to be carried to the catalyst 10 with the electric heater and the main catalyst 11 is increased together with the exhaust gas discharged from the engine body 1 to the exhaust system.

FIG. 9 is a block diagram showing the electrical configuration and the like of the ECU 41 in this embodiment. Unlike the configuration of the first embodiment, an ISCV 54 is additionally connected to the external output circuit 47. In this embodiment, the ECU 41
This constitutes the first drive control means, the warm-up determination means, and the second drive control means. When the engine is cold started, the ECU 41 controls the starter switch 31,
Based on various signals from the catalyst temperature sensor 32, the water temperature sensor 34, etc., the catalyst 10 with an electric heater is operated, and then the electric air pump 19 is driven. Further, the ECU 41 drives the injector 4 to control the fuel injection at the cold start. In addition, the ECU 41 drives the ISCV 54 in order to control idling during cold start. Further, the ECU 41 controls the air-fuel ratio of the engine based on a signal from the oxygen sensor 33 and the like (FB control).
To execute.

Next, in the gasoline engine system configured as described above, when the engine is cold started, the EC
The processing content for the exhaust gas purification control executed by U41 will be described. In this embodiment, the processing contents of the "secondary air supply control routine" are basically the same as those of the first embodiment, and the description will be focused on the other processing contents that are particularly different.

The flowchart of FIG. 10 shows a "startup control routine" executed by the ECU 41, which is started at the timing when the ignition switch 14 is switched to the ON position ON. Most of the processing contents of this routine are the same as those of the above-mentioned "start-time fuel injection control routine".

That is, when this process is started, first, at step 301, the values of the cooling water temperature THW, the engine speed NE, the intake air flow rate Q, etc., and the catalyst energization end flag XFE.
Read the status of each HC.

Then, at step 302, the target value of the fuel injection amount at start-up f0 is calculated based on the values of the cooling water temperature THW, the engine speed NE, the intake air flow rate Q and the like. Next, at step 303, it is judged if the catalyst energization completion flag XFEHC is "1". Here, if the catalyst energization end flag XFEHC is not "1", it is determined that the warm-up of the catalyst 10 with an electric heater has not been completed, and the routine proceeds to step 304. Then, in step 304, the injection process is executed based on the value of the fuel injection amount f0 at the time of starting obtained in step 302. That is,
Fuel is injected into the intake manifold 2 by driving and controlling the injector 4 based on the value of the fuel injection amount f0 at the time of starting.

In step 305, ISCV5
By closing 4, the processing of the fast idle is stopped. That is, the intake flow rate Q is not increased by the ISCV 54.

After that, in step 306, it is determined whether or not the value of the cooling water temperature THW is larger than the warm-up completion temperature value α. Then, when the value of the cooling water temperature THW is not larger than the warm-up completion temperature value α, it is determined that the warm-up of the engine body 1 has not been completed, the routine jumps to step 301, and the processing from step 301 is repeated. On the other hand, when the value of the cooling water temperature THW is larger than the warm-up completion temperature value α, it is determined that the warm-up of the engine body 1 is completed, and the process proceeds to step 309.

On the other hand, in step 303, when the catalyst energization end flag XFEHC is "1",
Assuming that the catalyst 10 with the electric heater has been warmed up, the process proceeds to step 307. And step 30
In step 7, as in step 304, the injection process is executed with the value of the fuel injection amount f0 at startup.

Subsequently, in step 308, IS
By opening the CV 54 to some extent, the fast idle process is executed. That is, the intake flow rate Q is increased by the ISCV 54. By this process, the engine speed NE during idling is increased, warming up of the engine body 1 is promoted, and the amount of exhaust gas discharged from the engine body 1 to the exhaust manifold 3 is increased.

Then, in step 309, it is determined whether the value of the cooling water temperature THW is larger than the warm-up completion temperature value α. Then, when the value of the cooling water temperature THW is not larger than the warm-up completion temperature value α, it is determined that the warm-up of the engine body 1 has not been completed, the routine jumps to step 301, and the processing from step 301 is repeated. on the other hand,
When the value of the cooling water temperature THW is larger than the warm-up completion temperature value α, it is assumed that the warm-up of the engine body 1 has been completed.
In step 310, the ISCV 54 is closed to stop the processing of the fast idle.

Then, step 306 or step 31
In step 311 after shifting from 0, the process of air-fuel ratio feedback control (FB control) of the engine is executed based on the signal from the oxygen sensor 32 and the like. Further, in step 312, the catalyst energization end flag XFEHC is cleared to "0", and the subsequent processing is ended.

As described above, the startup control process corresponding to the secondary air supply control process at startup is executed. As described above, in this embodiment, when the secondary air is supplied to the exhaust system at the cold start of the engine, after completion of warming up of the catalyst 10 with the electric heater on the upstream side is determined, The first idle process is executed for the first time to increase the intake air flow rate Q of the engine body 1. Therefore, in the engine body 1, the engine speed NE is increased by the amount of increase in the air, the warm-up of the engine body 1 is promoted, and the amount of exhaust gas discharged from the engine body 1 to the exhaust system is increased. It That is, the thermal energy to be carried to the catalyst with electric heater 10 and the main catalyst 11 is increased together with the exhaust gas discharged from the engine body 1 to the exhaust system.

Therefore, the heat energy increased by the exhaust gas is supplied to the main catalyst 11 on the downstream side in addition to the reaction heat generated from the catalyst 10 with the electric heater on the upstream side. The activation of 11 is promoted, and the warm-up of the main catalyst 11 is promoted. Moreover, here, since the amount of exhaust gas is increased by the first idle after the warm-up of the catalyst 10 with the electric heater is completed, the warm-up of the catalyst 10 with the electric heater is completed more than necessary. Exhaust gas is not emitted from the engine body 1. As a result, the catalyst 10 with the electric heater, the main catalyst 11 and the like can be quickly warmed up without deteriorating the exhaust emission more than necessary.

Besides, also in this embodiment, the same operation and effect as those of the first embodiment can be obtained. The present invention is not limited to the above-described embodiments, and a part of the configuration can be appropriately modified without departing from the spirit of the invention and can be carried out as follows.

(1) In each of the above embodiments, the upstream catalyst is the catalyst with electric heater 10 and the downstream catalyst is the main catalyst 11, but the upstream catalyst is equipped with the electric heater. It can also be a catalyst which is not.

(2) In each of the above-described embodiments, the three-way catalytic converters 8 and 9 are provided in series gasoline engines, but a plurality of exhaust systems are provided for each bank of a V gasoline engine. It can also be embodied by providing the above catalyst.

(3) In each of the above-described embodiments, the catalyst 10 with an electric heater is constructed such that an electrode is arranged at the center of a honeycomb core which constitutes a metal catalyst and electricity is conducted between the center electrode and the hub. However, the structure of the catalyst with an electric heater is not limited to this, and it is sufficient that the catalyst itself can be heated by energization.

(4) In the second embodiment, after the completion of warming up of the catalyst 10 with the electric heater is determined, the engine body 1
The thermal energy to be carried from the engine body 1 to the catalyst 10 with the electric heater and the main catalyst 11 is increased only by executing the fast idle without increasing the fuel injection amount f0 at the time of starting for the engine. On the other hand, after it is determined that the catalyst 10 with the electric heater has been warmed up, the fuel injection amount f0 at the time of starting is increased and the fast idle is executed, so that the catalyst 10 with the electric heater and the main catalyst are discharged from the engine body 1. The heat energy to be delivered to 11 may be increased.

[0083]

As described in detail above, according to the first aspect of the present invention, during the cold operation of the internal combustion engine, after activation of the upstream side catalyst of the plurality of catalysts in the exhaust system, Moreover, when the secondary air is supplied to the exhaust system, the thermal energy increasing means is operated to increase the thermal energy to be carried to the plurality of catalysts together with the exhaust gas discharged from the internal combustion engine to the exhaust system. . Therefore, before the activation of the upstream side catalyst, the heat energy to be carried to the catalyst along with the exhaust gas is not increased, so that the deterioration of the exhaust emission can be suppressed accordingly. As a result, the excellent effect that the catalyst can be quickly warmed up without deteriorating the exhaust emission is exhibited.

Further, according to the second aspect of the present invention, during the cold operation of the internal combustion engine, after the upstream side catalyst of the plurality of catalysts in the exhaust system is warmed up, and the secondary system is installed in the exhaust system. When air is supplied, the fuel equivalent to the sum of the first fuel amount required to maintain the rotation of the internal combustion engine and the second fuel amount required to obtain the heat amount required to warm up the catalyst. A quantity is supplied to the internal combustion engine. Therefore, the amount of the unburned component in the exhaust gas is increased by the second fuel amount, and the amount of the unburned component and the heat generated from the upstream side catalyst after the completion of warming up are combined, and the amount of the downstream side catalyst is increased. Warming up is promoted. Further, until the upstream side catalyst is completely warmed up, an unnecessarily large amount of fuel is not supplied to the internal combustion engine and the amount of unburned components does not increase.
As a result, the excellent effect that the catalyst can be quickly warmed up without deteriorating the exhaust emission is exhibited.

[Brief description of drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of a first invention.

FIG. 2 is a conceptual configuration diagram illustrating a basic conceptual configuration of a second invention.

FIG. 3 is a schematic configuration diagram showing a gasoline engine system in a first embodiment embodying the first and second inventions.

FIG. 4 is a block diagram showing a configuration of an ECU and the like in the first embodiment.

FIG. 5 is a flowchart showing a “secondary air supply control routine” executed by the ECU in the first embodiment.

FIG. 6 is a flowchart showing a “start-up fuel injection control routine” executed by the ECU in the first embodiment.

FIG. 7 is a time chart for explaining the operation of secondary air supply control and startup fuel injection control executed by the ECU in the first embodiment.

FIG. 8 is a sectional view showing a part of an intake pipe in a gasoline engine system according to a second embodiment of the first invention.

FIG. 9 is a block diagram showing a configuration of an ECU and the like in a second embodiment.

FIG. 10 is a flowchart showing a “startup control routine” executed by the ECU in the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Engine body as an internal combustion engine, 4 ... Injector which comprises fuel supply means and thermal energy increasing means, 3
... Exhaust manifold, 5-7 ... Exhaust pipe (3, 5-7 constitute exhaust system), 10 ... Catalyst with electric heater as upstream catalyst, 11 ... Main catalyst as downstream catalyst, 1
9 ... Electric air pump, 20 ... Air pipe, 25 ... Air control valve, 27 ... VSV (19, 20, 2)
5, 27, etc. constitute secondary air supply means), 41
... ECU (41 constitutes first drive control means, activation determination means, second drive control means, fuel amount calculation means, and fuel supply means control device), 53 ... bypass passage, 54 ... ISCV ( The heat energy increasing means is constituted by 53 and 54).

Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI Technical display location F01N 3/24 ZAB L F02D 33/00 310 D 9038-3G 41/04 315 8011-3G 330 L 8011-3G 43 / 00 301 H 7536-3G T 7536-3G L 7536-3G

Claims (2)

[Claims] 1. A plurality of catalysts arranged in series with an exhaust system of an internal combustion engine, fuel supply means for supplying fuel to the internal combustion engine, and secondary air from upstream of the plurality of catalysts to the exhaust system. Secondary air supply means for supplying the fuel, and a first air supply control means for driving and controlling the fuel supply means and the secondary air supply means, respectively, during cold operation of the internal combustion engine.
Drive control means, thermal energy increasing means for increasing the thermal energy to be carried to the plurality of catalysts together with the exhaust gas discharged from the internal combustion engine to the exhaust system, during cold operation of the internal combustion engine, Of the plurality of catalysts, the activation determination means for determining that the upstream side catalyst has been activated, and the secondary air supply when the activation determination means determines that the upstream side catalyst has been activated An exhaust gas purifying apparatus for an internal combustion engine, comprising: second drive control means for driving and controlling the thermal energy increasing means while the secondary air is being supplied by the means. 2. A plurality of catalysts arranged in series with an exhaust system of an internal combustion engine, fuel supply means for supplying fuel to the internal combustion engine, and secondary air from upstream of the plurality of catalysts to the exhaust system. A secondary air supply unit for supplying the first air amount, a first fuel amount necessary for the internal combustion engine to maintain rotation, and a heat amount necessary for warming up the catalyst during cold operation of the internal combustion engine. A fuel amount calculating means for calculating a second fuel amount necessary for obtaining the second fuel amount, and the second amount of fuel before the completion of warm-up of the upstream side catalyst of the plurality of catalysts during cold operation of the internal combustion engine. The fuel supply means is driven on the basis of the fuel amount of No. 1, after the warm-up of the upstream side catalyst is completed during the cold operation and during the supply of the secondary air by the secondary air supply means, 1 fuel quantity and the second
And a fuel supply means control device for driving the fuel supply means based on the sum of the fuel quantity and the fuel quantity.