JPH06264730A - Air introducing/controlling device inside exhaust pipe of internal combustion engine - Google Patents

Abstract

PURPOSE:To enhance the purification efficienty of a catalytic converter by detecting the specific component density in exhaust gas by means of an air-fuel ratio sensor provided on the downstream side of the catalytic converter, and controlling an air introducing device on the basis of the detected air-fuel ratio. CONSTITUTION:An air-fuel ratio sensor 17 is provided on the downstream side of a catalytic converter 8 of an exhaust pipe 7, and the density of oxygen included in gas discharged from an internal combustion engine 1 is detected and input into a fuel control unit 15A. A control valve 18 is provided on the downstream side of an air pump 11 of an air introducing pipe 10, so as to adjust the quantity of air to be discharged to the exhaust pipe 7 from the air pump 11. When the feedback control of the air-fuel ratio is started by the fuel control unit 15A, an introduced air capacity control unit 19 receives an interruption signal S3 and controls the capacity of air to flow to a control valve 18 so that it may become the fixed capacity by an introducing capacity adjusting signal S4. The active efficiency of the catalytic converter can be early enhanced by this structure, and also the purification of exhaust gas can be enhanced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust pipe air introduction control device for introducing air into an exhaust pipe of an internal combustion engine for purifying exhaust gas.

[0002]

2. Description of the Related Art A technique in which a catalyst is provided in an exhaust pipe for purifying exhaust gas of an internal combustion engine is generally known. Further, immediately after the internal combustion engine having a low catalyst temperature and a low purification efficiency is started, In the conventional technology, air is introduced upstream of the catalyst to accelerate the oxidation of HC (hydrocarbon) and CO (carbon monoxide) in the catalyst to accelerate the temperature rise of the catalyst and improve the purification efficiency. Better known.

FIG. 9 is a block diagram showing a conventional exhaust pipe air introduction control device. In FIG. 9, 1 is an internal combustion engine for discharging harmful gas by combustion, 2 is an intake pipe of the internal combustion engine 1, and 3 is an intake pipe. 2 is an air cleaner provided at the intake port for removing dust and dirt, and 4 is an air cleaner 3 in the intake pipe 2.
An air flow sensor 5, which is provided on the downstream side of the internal combustion engine 1 for measuring the amount of air taken into the internal combustion engine 1, is provided inside the intake pipe 2, and the passage area of the intake pipe 2 is changed to change the internal combustion engine 1
A throttle valve 6 for adjusting the amount of air taken in to the internal combustion engine 1 supplies fuel to the internal combustion engine 1. Therefore, fuel sent by a fuel pump (not shown) is sprayed toward an intake valve (not shown) of the internal combustion engine 1. For injecting fuel in a uniform manner to supply fuel, 7 is an exhaust pipe for exhausting exhaust gas, 8 is a catalytic converter provided in exhaust pipe 7 for purifying exhaust gas by a chemical reaction, 9 is air for exhaust pipe 7. Is an air introducing device for introducing air into the exhaust pipe 7, and 11 is provided in the air introducing pipe 10 for introducing air into the exhaust pipe 7 for forcibly introducing air into the exhaust pipe 7. Air pump, 1
2 is provided in the air introduction pipe 10, and a check valve for preventing exhaust gas from flowing backward from the exhaust pipe 7 side to the intake pipe 2 side, and 13 is provided in the air introduction pipe 10 to remove the air introduced by the air pump. A heater 14 for heating is provided in the exhaust pipe 7, and for detecting the oxygen concentration contained in the exhaust gas, for example, an air-fuel ratio sensor including a zirconia oxygen sensor using a zirconia element or a titania oxygen sensor using a titania element. , 15 are connected to the air-fuel ratio sensor 14 and are also connected to the injector 6, and a fuel controller for controlling the injector 10 according to the output of the air-fuel ratio sensor 14, 16 are connected to the fuel controller 15 and the heater 13 Is a heater controller for controlling the heater 13.

Next, the operation will be described. The air purified by passing through the air cleaner 3 is forcibly sucked by the air pump 11 in the air introduction device 9, heated by the heater 13, and passed through the check valve 12 to the catalytic converter 8
Is introduced into the exhaust pipe 7 upstream. Next, the air introduced by the air introduction device 9 is mixed with the gas discharged from the internal combustion engine 1 in the exhaust pipe 7. Exhaust gas components HC, CO, etc. undergo oxidation reaction in the catalytic converter 8 in the mixed gas to become H ₂ O, CO _2, etc., which are purified and become exhaust gas released into the atmosphere.

Further, the fuel controller 15 determines the amount of fuel discharged by the injector 6 from the output of the air flow sensor 4 and the rotation speed of the internal combustion engine, and determines the amount of fuel according to the output S1 of the air-fuel ratio sensor 14. The corrected fuel amount is adjusted to be adjusted, and the signal S2 for driving the injector 6 is given to feedback control the fuel amount so that the air-fuel ratio becomes a predetermined air-fuel ratio, for example, the stoichiometric air-fuel ratio.

Further, the introduction of air into the exhaust pipe 7 by the air pump 11 is started at the time of starting the internal combustion engine 1 and continued until the internal combustion engine is stopped. That is, the air pump 11 is constantly operated during the operation of the internal combustion engine 1 to constantly introduce air.

[0007]

The conventional exhaust pipe air introduction control device is constructed as described above, and the air-fuel ratio sensor 1 is used.
4, the oxygen concentration contained in the exhaust gas is detected, and the ratio of air and fuel used for combustion is a predetermined air-fuel ratio,
For example, the fuel controller 15 controls so that the purification efficiency of the catalyst is close to the best theoretical air-fuel ratio. However, in the conventional exhaust pipe air introduction control device, even after the air-fuel ratio control by the fuel controller 15 or the like is started in this way,
Since the air pump 11 continues to operate and the amount of air introduced into the exhaust pipe 7 is not changed, the catalytic converter 8 performs feedback control on the stoichiometric air-fuel ratio that exhibits the best purification rate characteristics by the air-fuel ratio control. When this is done, an oxygen excess state will occur in the upstream portion of the catalytic converter 8, and the excess oxygen will produce CO or H for reducing NO (nitrogen oxide).
There is a problem that the NO conversion component in the catalytic converter 8 is deteriorated because the NO reduction component almost disappears due to the oxidation reaction with C, resulting in an increase in the NO discharged into the atmosphere.

In order to solve such a problem, for example, the amount of air introduced into the exhaust pipe 7 may be controlled according to a predetermined air-fuel ratio. In this case, however, after the air-fuel ratio control is started, Since the amount of introduced air will be controlled, the air-fuel ratio introduced into the catalyst by the amount of introduced air before the start of air-fuel ratio control is unknown. Therefore, there is a problem that it is not known whether the reaction in the catalyst is optimally performed by the introduced air.

On the other hand, since the air introducing device is added for the purpose of early activation of the catalyst for cleaning the exhaust gas as described above, if the air introducing device fails, the gas discharged from the internal combustion engine is deteriorated. For this reason, it is necessary to detect the failure of the air introduction device at an early stage and to notify the driver with certainty to take appropriate processing. However, the conventional air introduction control device for the internal combustion engine cannot detect the failure early. There was a problem.

The present invention has been made to solve the above-mentioned problems. By using the catalytic converter under the optimum conditions, the purification efficiency of the catalytic converter can be improved and the failure of the air introducing device can be promptly achieved. It is an object of the present invention to obtain an air introduction control device for an internal combustion engine that can be reliably detected.

[0011]

An air introduction control device for an internal combustion engine according to claim 1 of the present invention is provided on a downstream side of a catalytic converter, and an air-fuel ratio sensor for detecting a concentration of a specific component in exhaust gas, An air introduction amount control means for controlling the air introduction device to control the air introduction amount based on the air fuel ratio detected by the air fuel ratio sensor is provided.

An air introduction control device for an internal combustion engine according to claim 2 of the present invention is provided on the downstream side of the catalytic converter, and an air-fuel ratio sensor for detecting the concentration of a specific component in the exhaust gas, and a catalyst for the catalytic converter. If it is determined that the catalyst is not activated, based on the output signal of the determining means and the determining means, the air-fuel ratio detected by the air-fuel ratio sensor Based on the output signal of the air introduction amount control means controlling the introduction device to control the air introduction amount, and the output signal of the determination means, if it is determined that the catalyst is not activated, the air-fuel ratio detected by the air-fuel ratio sensor And an air-fuel ratio control means for controlling the air-fuel ratio by controlling the fuel control device.

Further, an air introduction control device for an internal combustion engine according to claim 3 of the present invention is provided on the downstream side of the catalytic converter, and an air-fuel ratio sensor for detecting the concentration of a specific component in the exhaust gas, and this air-fuel ratio sensor. And a failure detecting means for detecting a failure of the air introducing device based on the output signal of the above.

[0014]

According to the air introduction control device for an internal combustion engine according to claim 1 of the present invention, the air-fuel ratio sensor detects the concentration of the specific component in the exhaust gas at the downstream side of the catalytic converter.
The air introduction control means controls the air introduction device based on the air-fuel ratio detected by the air-fuel ratio sensor. Therefore, the air introduction control means can feed back the exhaust gas purification result by the catalytic converter to control the air introduction amount.

Further, according to the air introduction control apparatus for an internal combustion engine according to claim 2 of the present invention, the air-fuel ratio sensor detects the concentration of the specific component in the exhaust gas on the downstream side of the catalytic converter. Further, the judging means judges that the catalyst of the catalytic converter has been activated. Further, the air introduction amount control means controls the air introduction device based on the output signal of the determination means, based on the air-fuel ratio detected by the air-fuel ratio sensor when it is determined that the catalyst is not activated. Control the amount of air introduced. Then, the air-fuel ratio control means, based on the output signal of the determination means, when it is determined that the catalyst is not activated, using the air-fuel ratio detected by the air-fuel ratio sensor, to control the fuel control device Control the air-fuel ratio.

Further, according to the air introduction control device for an internal combustion engine according to claim 3 of the present invention, the air-fuel ratio sensor detects the concentration of the specific component in the exhaust gas on the downstream side of the catalytic converter. Then, the failure detecting means detects a failure of the air introducing device based on the output signal of the air-fuel ratio sensor.

[0017]

【Example】

Example 1. Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment. In the figure, 1 to 14 are the same as those shown in FIG. Figure 9
17 is provided in the exhaust pipe 7 on the downstream side of the catalytic converter 8 and detects an oxygen concentration contained in the gas discharged from the internal combustion engine 1 to detect an air-fuel ratio in the engine. The same as the air-fuel ratio sensor 14 is used. 18 is provided downstream of the air pump 11 in the air introduction pipe 10, adjusts the amount of air discharged from the air pump 11 and introduced into the exhaust pipe 7,
It is a control valve that constitutes an air introduction amount control means together with an introduction air controller 19 described later, and is, for example, a duty control valve using an electromagnetic solenoid.

Reference numeral 19 determines the amount of air introduced into the exhaust pipe 7 in response to conditions such as the load of the internal combustion engine 1, the number of revolutions and various temperatures, and drives the control valve 18 by the introduction amount adjusting signal S4. When the fuel controller 15A starts the feedback control of the air-fuel ratio, it is an introduction air controller that receives the interrupt signal S3 and controls the amount of air flowing through the control valve 18 to be a predetermined amount.

The introduced air controller 19 is the fuel controller 1
It may be integrated with 5A. The fuel controller 15A obtains the basic fuel injection pulse width from the intake air amount detected by the air flow sensor 4 and the engine rotation speed, corrects the temperature such as the water temperature, and outputs the air-fuel ratio sensor 14 and the air-fuel ratio sensor 17. The air-fuel ratio feedback correction is performed by S1 and S5 so that the air-fuel ratio becomes the stoichiometric air-fuel ratio, and the injection pulse width is determined. The fuel controller 15A drives the injector 6 by the fuel injection signal S2 to control the fuel.

Next, the air-fuel ratio control operation of the exhaust pipe air introducing device configured as described above will be explained using the control block diagram of FIG. 2 and the behavior of the air-fuel ratio control of FIG. First, the air-fuel ratio control in this device will be described with reference to the behavior of FIG. 3 based on the control block diagram of FIG. A block 201 indicates a preset second predetermined signal (target value of air-fuel ratio control), and the adder a first compares the output signal V2 of the air-fuel ratio sensor 17 with the output signal of the block 201. Based on the output deviation V2S, the second P
The I controller 202 PI-controls the output deviation V2S and outputs a predetermined correction output signal V2SH. Next, a block 203 shows a preset first predetermined signal, which is added to the correction output signal V2SH in the adder b and used as the determination value VTH of the air-fuel ratio sensor 14.

Next, in the adder c, the air-fuel ratio sensor 1
4 is compared with the determination value VTH, and the first PI controller 204 calculates the air-fuel ratio feedback correction amount CFB based on this comparison value.

Here, the air-fuel ratio feedback correction amount CFB
Indicates that the magnitude of the output signal of the air-fuel ratio sensor 14 is the judgment value VT.
It can be seen that the number of times of crossing H is substantially equal to the cycle. Next, in the multiplier d, this correction amount CFB is multiplied by the basic fuel amount shown in block 205, which is calculated from the intake air amount detected by the air flow sensor 4. The multiplication result is further multiplied by the output signal from the block 206 in the multiplier e to calculate the final fuel discharge amount. In this block 206, the correction amount corresponding to the warm-up state of the engine calculated based on the signal from the water temperature sensor (not shown) and the acceleration / deceleration state from the signal from the throttle opening sensor (not shown) are detected. A fuel correction amount such as a correction amount corresponding to the acceleration / deceleration state is output. The injector 6 is calculated from the fuel amount obtained by the multiplier e.
In order to calculate the drive time of the fuel injection system, the correction coefficients of the injection time of the injector 6 and the dead time of the injector 6 are calculated in blocks 207 and 208, and the outputs thereof are multiplied by the fuel amounts in multipliers f and g, respectively. It As described above, the air-fuel ratio control is performed by correcting the determination value of the air-fuel ratio sensor 14 using the output signal of the air-fuel ratio sensor 17.

By the above control operation, the air-fuel ratio sensor 17 is air-fuel ratio controlled so as to have a predetermined value. That is, if the output of the air-fuel ratio sensor 17 is lean, the air-fuel ratio control is controlled to the rich side. Further, it can be seen that when the output of the air-fuel ratio sensor 17 is rich, the air-fuel ratio control is controlled to the lean side. As described above, the air-fuel ratio control is performed based on the output signals of the air-fuel ratio sensors 14 and 17 provided upstream and downstream of the catalytic converter 8. That is, the air-fuel ratio control is performed using the detected air-fuel ratio detected by the air-fuel ratio sensor 17 provided downstream of the catalytic converter 8.

Next, the operation of controlling the introduced air amount of the air heated by the heater 13 using the air-fuel ratio sensor 17 will be described with reference to FIGS. 4 and 5. First, FIG. 4 will be described. In step S401, it is determined whether or not a predetermined time has elapsed since the engine was started. This predetermined time is
The time is set in advance as the time required for the catalyst of the catalytic converter 8 to fully exert its purifying action. Since the predetermined time period varies depending on the driving condition, it may be changed depending on the driving condition. If the predetermined time has elapsed in step S401, it is considered that the catalyst is fully operating, so in step S402 the air-fuel ratio control described above is executed, and in step S403, the amount of introduced air is set to zero.

On the other hand, if the predetermined time has not elapsed in step S401, the purification effect of the catalyst is not sufficient and the purification efficiency is still low. Therefore, it is necessary to accelerate the temperature rise of the catalyst by the oxidation reaction of CO and HC. is there. Therefore, step S404
Then, the normal air-fuel ratio control is stopped, and feedback correction control using only the conventional air-fuel ratio sensor 14 or open-loop control according to the operating state is performed. Then, the introduced air amount control is executed in step S405. Incidentally, step S
In 401, it is determined whether or not the catalyst of the catalytic converter 8 can completely exert the purifying action based on whether or not a predetermined time has elapsed after the start of the internal combustion engine 1. However, the temperature sensor is provided in the catalytic converter 8 or in the vicinity thereof. May be provided and the determination may be made by detecting whether or not the temperature has reached the predetermined temperature.

Details of the control of the introduced air amount described above will be described with reference to FIG. First, in FIG. 5, the amount of introduced air is calculated in step S501 according to the operating state so that the heat conduction to the catalyst and the oxidation reaction are optimally performed. However, at a predetermined amount of introduced air, it is unknown whether the heat conduction to the catalyst and the oxidation reaction are optimally performed. Therefore, in the following steps, the catalyst reaction is performed based on the output signal of the air-fuel ratio sensor 17. It is determined whether or not it is performed correctly, and the amount of introduced air is controlled according to the determination result.

First, in step S502, it is determined whether or not a predetermined time, for example, 0.1 sec has elapsed. If the predetermined time has not elapsed, the process returns. On the other hand, if the predetermined time has elapsed, the process proceeds to step S503, the output signal of the air-fuel ratio sensor 17 is monitored, and it is determined whether the air-fuel ratio is rich or lean based on the output signal of the air-fuel ratio sensor 17. As a result, if the air-fuel ratio is rich, the process proceeds to step S504,
It is judged to be rich because the amount of introduced air is small,

Amount of introduced air (current time) = amount of introduced air (previous time) × (1 + predetermined value) (1)

The amount of introduced air is increased as. On the other hand, if the air-fuel ratio is lean, the routine proceeds to step S505, where the amount of introduced air is large, so it is determined that it has become lean,

Amount of introduced air (current time) = amount of introduced air (previous time) × (1-predetermined value) (2)

The amount of introduced air is reduced as. Through the above processing, the amount of introduced air is controlled based on the output signal of the air-fuel ratio sensor 17 to optimally carry out the catalytic reaction.

It should be noted that the above-mentioned increase / decrease of the introduced air amount is performed by using the equations (1) and (2), but a predetermined value may be added to or subtracted from the introduced air amount. However, if these are used as coefficients, there is a merit that errors due to operating conditions are easily absorbed. On the other hand, although the amount of introduced air is reduced in the case of lean, the amount of introduced air does not have to be changed in case of lean in order to accelerate the oxidation reaction of CO and HC. Further, in the above-described embodiment, the introduced air amount control is performed on the heated introduced air by the catalyst downstream air-fuel ratio, but it goes without saying that the introduced air amount control effect is produced even if the introduced air is not heated.

Example 2. In the first embodiment described above, the air-fuel ratio sensor 17 provided downstream of the catalytic converter 8 uses the λ type O ₂ sensor, that is, the sensor that determines whether the air-fuel ratio is richer or leaner than the stoichiometric air-fuel ratio. The fuel ratio could be judged to be leaner or richer than the theoretical air-fuel ratio. Therefore, as compared with the case of the first embodiment, a linear O ₂ sensor such as a limiting current control type is used as the air-fuel ratio sensor 17 so that the purification action by the catalytic converter 8 can be more efficiently performed by the heated introduced air. It is also possible to detect the fuel ratio linearly and control the amount of introduced air according to the air-fuel ratio detected linearly.

The control when this linear O ₂ sensor is used as the air-fuel ratio sensor 17 will be described below with reference to FIG. First, in step S601, as in step S501 of FIG. 5, the amount of introduced air according to the operating state is calculated. Next, in step S602, engine rotation,
The target air-fuel ratio set in advance is calculated according to the operating state of either the load state or the warm air state.

Next, in step S603, it is determined whether or not a predetermined time has elapsed, and if it has not elapsed, it is considered that the change in the air-fuel ratio after the introduced air change control cannot be detected, and the routine proceeds to return. On the other hand, if the predetermined time has elapsed, step S60
In step S604, the air-fuel ratio sensor 17 detects the air-fuel ratio downstream of the catalyst. Next in step S605.
Then, the deviation between the target air-fuel ratio calculated in step S602 and the air-fuel ratio detected in step S604 is calculated, and the amount of introduced air is controlled according to this deviation.

Next, in step S606, it is determined whether the deviation is positive or negative. If the deviation is positive, the air-fuel ratio downstream of the catalytic converter 8 is richer than the target, so the routine proceeds to step S607, where the amount of introduced air is increased by the same calculation as in step S504 of FIG. On the other hand, if the deviation is negative, the downstream air-fuel ratio of the catalyst is leaner than the target, so the routine proceeds to step S608, where the introduced air amount is reduced by the same calculation as in step S505 of FIG.
As described above, the amount of introduced air is controlled so that the air-fuel ratio downstream of the catalyst becomes the target value. Incidentally, steps S606 to S606
Although the deviation is determined to be positive or negative in 608, it is also possible to improve the control performance by providing a dead zone and not changing the amount of introduced air within the dead zone.

Example 3. In the first and second embodiments described above, the case where the air-fuel ratio downstream of the catalyst is detected and the amount of introduced air is controlled from the detected air-fuel ratio has been described. Next, as a third embodiment, failure detection of the air introducing device will be described with reference to FIG. The failure detection of the air introducing device is performed by the above-mentioned FIG.
It is performed when the air introduction control shown in FIG. 6 is being performed.

First, in step S701, it is determined whether or not a predetermined time has elapsed since the internal combustion engine 1 was started. If the predetermined time has not elapsed, after the introduction air change control, it is considered that the air-fuel ratio downstream of the catalytic converter 8 has not changed, and the process returns. If the predetermined time has elapsed, the process proceeds to step S702, and it is determined whether or not the change control of the amount of introduced air by the air-fuel ratio has been performed before the predetermined time has elapsed. When the change control is not performed, the air-fuel ratio does not change downstream of the catalytic converter 8 and the process returns. On the other hand, when the change control is being performed, the process proceeds to step S703. After step S703, a change in the air-fuel ratio downstream of the catalytic converter 8 from a predetermined time before to this time is detected.

Therefore, first, in step S703, it is determined whether or not the air-fuel ratio downstream of the catalytic converter 8 before the elapse of the predetermined time is detected, based on whether or not the previous value is stored. If not stored, the process proceeds to step S707, and the detected air-fuel ratio of this time is stored as the previous value. If it is stored, the process proceeds to step S704. In S704, the previously stored value, that is, the deviation between the previously detected air-fuel ratio and the currently detected air-fuel ratio is calculated, and it is determined whether the air-fuel ratio deviation, that is, the change in the air-fuel ratio is equal to or greater than a predetermined value. If the change is equal to or larger than the predetermined value, the process proceeds to step S705, and since the amount of introduced air is changed, it is determined to be normal. Here, the predetermined value in step S704 may be a value corresponding to the change amount of the introduced air amount of the air-fuel ratio.

On the other hand, if the change is less than the predetermined value, the flow proceeds to step SS706 and the amount of introduced air has not changed, so it is determined that the air introducing device has failed. It should be noted that, in FIG. 7, the normality and the failure are determined by one determination, but the failure determination may be performed by determining that the state continues. Next, in step S707, the detected air-fuel ratio is updated as described above. With the above processing, the failure determination of the air introduction device is performed based on the change in the air-fuel ratio.

Example 4. A failure detection different from the third embodiment will be described as a fourth embodiment with reference to FIG. Example 4 is shown in FIG.
The detection can be performed both when the air introduction control shown in 6 is executed and when it is not executed. First, in step S801, a target air-fuel ratio according to the operating state is obtained. If the air introduction device is normal, air should be introduced according to the operating state, and the air-fuel ratio downstream of the catalytic converter 8 should substantially match the target air-fuel ratio. Next, in step S802, the air-fuel ratio sensor 17 detects the air-fuel ratio, and in step S803 the deviation between the target air-fuel ratio and the detected air-fuel ratio is calculated to determine whether the deviation of the air-fuel ratio is equal to or greater than a predetermined value. If the deviation is less than the predetermined value, step S80
4, the air is considered to be normally introduced, and the air introducing device determines that the air is normal. On the other hand, if the deviation is equal to or larger than the predetermined value, it is determined that the introduced air has not entered normally, and the failure of the air introducing device is determined. In the process of the fourth embodiment as well, the predetermined value may be changed according to the operating condition, or continuation of the condition may be added to the failure determination. As described above, when the air is introduced, it is possible to detect the failure of the air introducing device by determining whether or not the preset target air-fuel ratio is obtained using the actual air-fuel ratio downstream of the catalytic converter 8. it can.

[0042]

As described in detail above, according to the air introduction control device for an internal combustion engine according to the first aspect of the present invention, it is provided on the downstream side of the catalytic converter and detects the concentration of the specific component in the exhaust gas. Since it has an air-fuel ratio sensor and an air introduction amount control means for controlling the air introduction device by controlling the air introduction device on the basis of the air-fuel ratio detected by the air-fuel ratio sensor, the activation efficiency of the catalytic converter is increased early. Thus, it is possible to improve the purification of exhaust gas.

An air introduction control device for an internal combustion engine according to claim 2 of the present invention is provided on the downstream side of the catalytic converter, and an air-fuel ratio sensor for detecting the concentration of a specific component in the exhaust gas, and a catalyst for the catalytic converter. If it is determined that the catalyst is not activated, based on the output signal of the determining means and the determining means, the air-fuel ratio detected by the air-fuel ratio sensor Based on the output signal of the air introduction amount control means controlling the introduction device to control the air introduction amount, and the output signal of the determination means, if it is determined that the catalyst is not activated, the air-fuel ratio detected by the air-fuel ratio sensor The air-fuel ratio control means for controlling the fuel control device to control the air-fuel ratio based on Converter to be able to use the original optimum purification efficiency, it has an effect that it is possible to enhance the efficiency of purifying the exhaust gas.

Further, according to the air introduction control apparatus for an internal combustion engine according to claim 3 of the present invention, an air-fuel ratio sensor which is provided on the downstream side of the catalytic converter and detects the concentration of a specific component in the exhaust gas, and this air-fuel ratio sensor. Since there is provided the failure detection means for detecting a failure of the air introducing device based on the output signal of the fuel ratio sensor, there is an effect that the failure of the air introducing device can be surely notified to the driver from the result after the catalytic reaction. .

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment.

FIG. 2 is a block diagram showing air-fuel ratio control of the first embodiment.

FIG. 3 is a time chart showing air-fuel ratio control.

FIG. 4 is a flowchart showing air introduction control to an exhaust pipe.

FIG. 5 is a flowchart showing introduced air amount control.

FIG. 6 is a flowchart showing introduced air amount control in the second embodiment.

FIG. 7 is a flowchart for detecting a failure in the third embodiment.

FIG. 8 is a flowchart for detecting a failure in the fourth embodiment.

FIG. 9 is a block diagram showing a conventional exhaust pipe air introduction control device for an internal combustion engine.

[Description of Reference Signs] 1 internal combustion engine 7 exhaust pipe 8 catalytic converter 9A air introduction device 15A fuel controller 17 air-fuel ratio sensor 18 control valve 19 introduction air controller

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[Procedure amendment]

[Submission date] September 3, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 2

[Correction method] Change

[Correction content]

[Procedure 3]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 3

[Correction method] Change

[Correction content]

Claims (3)

[Claims] 1. An exhaust pipe of an internal combustion engine is provided with a catalytic converter for purifying exhaust gas, and an air introduction device for introducing air into the exhaust pipe is provided, and the air introduction is performed so as to enhance purification efficiency of the catalytic converter. In an exhaust pipe air introduction control device for an internal combustion engine that controls the device, an air-fuel ratio sensor that is provided on the downstream side of the catalytic converter and detects a specific component concentration in exhaust gas, and an air-fuel ratio sensor that detects the air-fuel ratio sensor. An air introduction amount control device for an internal combustion engine, comprising: an air introduction amount control means for controlling the air introduction device by controlling the air introduction device based on a fuel ratio. 2. An exhaust pipe of an internal combustion engine is provided with a catalytic converter for purifying exhaust gas, and an air introduction device is provided for introducing air into the exhaust pipe in order to enhance purification efficiency of the catalytic converter. In an exhaust pipe air introduction control device for an internal combustion engine, which is provided with a fuel control device that controls fuel supplied to the internal combustion engine to perform air-fuel ratio control in order to enhance purification efficiency of the converter, and is provided on the downstream side of the catalytic converter. The air-fuel ratio sensor for detecting the concentration of the specific component in the exhaust gas, the judgment means for judging that the catalyst of the catalytic converter is activated, and the catalyst is activated based on the output signal of this judgment means. If it is determined that there is no air introduction amount control that controls the air introduction amount by controlling the air introduction device based on the air-fuel ratio detected by the air-fuel ratio sensor. Control means, based on the output signal of the determination means, when it is determined that the catalyst is not activated, using the air-fuel ratio detected by the air-fuel ratio sensor, control the fuel control device to control the air-fuel ratio An air-fuel ratio control means for controlling the air-fuel ratio, and an air introduction control device for an exhaust pipe of an internal combustion engine, comprising: 3. An internal combustion engine exhaust pipe is provided with a catalytic converter for purifying exhaust gas, and an air introducing device for introducing air into the exhaust pipe is provided, and the air introduction is performed so as to enhance the purification efficiency of the catalytic converter. In an exhaust pipe air introduction control device for an internal combustion engine that controls the device, an air-fuel ratio sensor that is provided on the downstream side of the catalytic converter and detects the concentration of a specific component in the exhaust gas, and an output signal of this air-fuel ratio sensor A failure detection means for detecting a failure of the air introduction device based on the above, and an air introduction control device for an exhaust pipe of an internal combustion engine, comprising: