JPH07127444A - Secondary air lead-in control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To accelerate the atomization of injected fuel so as to heighten the combustion efficiency of an internal combustion engine and to reduce HC and CO discharged from the engine, and heighten the oxidizing reaction efficiency with exhaust gas in a catalyst so as to improve exhaust gas purifying efficiency by leading heated air into the exhaust pipe and intake pipe of the internal combustion engine. CONSTITUTION:Heated air is led into an exhaust pipe 6 and an intake pipe 2. At the low temperature time of an engine, heated air is fed to the intake pipe 2 to make an air-fuel ratio lean by 10-20%, thus accelerating the atomization of fuel. At the time of the high temperature state, the engine 1 is lean-combusted so as to be able to reduce fuel consumption. The heated air is fed into the exhaust pipe 6 until the catalyst temperature reaches the specified value or higher so as to accelerate exhaust gas purification at the catalyst.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention sufficiently heats the air introduced into the exhaust pipe and the intake pipe of an internal combustion engine to promote the activation of the catalyst and also promotes atomization of the supplied fuel to generate exhaust gas. The present invention relates to a secondary air introduction control device for an internal combustion engine that promotes purification.

[0002]

2. Description of the Related Art A conventional control device of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 50-100423, and when air at room temperature is introduced into the exhaust pipe and the temperature of the catalyst rises, air is introduced to the intake pipe side. There is a device that is structured to send.

When air is introduced into the exhaust pipe, a catalyst promotes a chemical reaction that oxidizes hydrocarbons (hereinafter referred to as HC), carbon monoxide (hereinafter referred to as CO), etc. in the exhaust gas. As a result, the reaction heat causes the catalyst to become overheated and damaged, so most of the air sent to the exhaust pipe is sent to the intake pipe side. Therefore, the catalyst is cooled to prevent damage and the engine is burned lean so that HC,
Suppress CO emissions.

A conventional secondary air introduction control device will be described with reference to FIG. FIG. 10 is a block diagram showing a conventional secondary air introduction control device for an internal combustion engine. In the figure, 1 is an internal combustion engine (hereinafter,
(Indicated as engine) 2 is an intake pipe for sending air into the engine 1, 3 is an air cleaner for removing dust contained in the air sent into the intake pipe 2, and 4 is a flow rate of air taken into the engine 1. Air flow sensor for measuring
This throttle valve 5 is provided for the throttle valve 5 to adjust the amount of air taken into the engine 1 by varying the passage area of the intake pipe 2.

Reference numeral 6 denotes an exhaust pipe connected to the exhaust port of the engine 1. The exhaust pipe 6 sends HC and CO in the harmful exhaust gas discharged from the engine 1 to a catalytic converter 7 for purifying by chemical reaction. Reference numeral 8 is an air pump that pressurizes the air sent through the air cleaner 3 and sends it to the air introducing pipe 9. This air pump 8 is a mechanical type driven by the engine 1 or an electric machine that drives a motor by a DC power source to send air. Expressions are used. Reference numeral 10 denotes the air discharged by the air pump 8 from the exhaust pipe 6 side and the intake pipe 2
It is a switching valve that switches to the side and sends.

Reference numeral 11 denotes a flow rate control valve for adjusting the amount of air sent from the switching valve 10 to the intake pipe 2 through the intake introduction pipe 12.
Reference numeral 3 is an exhaust introduction pipe for sending the air switched by the switching valve 10 to the exhaust pipe 6, the end of the introduction pipe 13 is connected to the air introduction port of the exhaust pipe 6, and the secondary air is introduced from the introduction port to the catalytic converter 7. Sent. Reference numeral 14 is a check valve provided so that exhaust gas does not flow back to the intake pipe 2, and 15 is a catalytic converter 7.
Is a temperature sensor that detects the temperature of the temperature sensor, and 16 is a controller that controls the switching valve 10 and the flow control valve 11 according to the output of the temperature sensor 15.

Next, the operation will be described. The clean air that has passed through the air cleaner 3 passes through the air flow sensor 4, and is injected into the engine 1 through the intake pipe 2 in an amount according to the opening degree of the throttle valve 5 from a fuel injector (not shown), which is an injector. Sent with. The sent mixture of air and fuel is burned in the engine 1, and harmful exhaust gas generated at the time of burning is discharged to the exhaust pipe 6.

On the other hand, the air pump 8 rotates in accordance with the rotation of the engine 1, takes in the clean air that has passed through the air cleaner 3, pressurizes it, and sends it to the switching valve 10. Then
When the temperature of the catalytic converter 7 is in a low temperature state, the switching valve 10 connects the exhaust introduction pipe 13 and the discharge port of the air pump 8 to each other, and when the catalytic converter 7 is in an overheated state,
A control signal is applied by the controller 16 so as to connect the intake introduction pipe 12 and the discharge port of the air pump 8 to switch the air passage.

The air sent to the exhaust introduction pipe 13 is introduced into the exhaust pipe 6 and the catalytic converter 7 via the check valve 14. Further, the air sent to the intake introduction pipe 12 receives a control signal from the controller 16 by the flow rate control valve 11, and the air-fuel mixture of fuel and air taken in by the engine 1 is 10% leaner than the theoretical air-fuel ratio. The amount of air is adjusted so that the condition is reached. By this switching control of the air introduction position, the exhaust pipe 6
In the catalytic converter 7, the air introduced into the exhaust gas reacts with HC and CO, which are harmful components of the exhaust gas of the engine 1, to purify the exhaust gas. Further, the air introduced into the intake pipe 2 makes the mixer lean and causes HC generated by combustion,
CO can be reduced.

[0010]

Since the conventional secondary air introduction control device for the internal combustion engine is constructed as described above,
When air at normal temperature is introduced into the exhaust pipe 6, the air temperature is low and the exhaust gas temperature is lowered, so that the temperature rise of the catalytic converter 7 is hindered and the exhaust gas purification performance is deteriorated. Further, when air is sent to the intake pipe 2 and the engine 1 is made to burn lean, the negative pressure in the intake pipe 2 decreases, and the atomization state of the fuel injected from the fuel injection device deteriorates, and the combustion state deteriorates. Therefore, incomplete combustion results in the emission of a large amount of HC and CO, and when the engine misfires due to incomplete combustion,
There were problems such as loss of stability of the engine.

The present invention has been made to solve the above problems, and heats the air introduced into the exhaust pipe of an engine to prevent the exhaust gas temperature from decreasing, and
The catalytic converter is rapidly heated, the temperature rise of the catalytic converter is promoted, and the exhaust gas purification reaction is promoted. Further, by sending high temperature air to the intake pipe, atomization of the supplied fuel can be promoted, and particularly when starting and warming up immediately after starting, a mixture richer than the theoretical air-fuel ratio is supplied.
Although the emission amounts of C and CO increase, the air-fuel mixture can be diluted with the promotion of atomization, and the emission of HC and CO can be suppressed. An object is to obtain a secondary air introduction control device for an internal combustion engine.

[0012]

A secondary air introduction control device for an internal combustion engine according to a first aspect of the present invention introduces secondary air to control an introduction amount, and an secondary air introduction amount control means. Heating means for heating, an exhaust introduction pipe connected for introducing air into the exhaust pipe, a reverse prevention means for preventing backflow of exhaust gas into the air introduction passage, and a connection for introducing air into the intake pipe Intake air intake pipe, flow control means for varying the passage area of the intake air intake pipe, catalyst activation determination means for determining the activation state of the catalyst, and the introduction air amount and heating depending on the operating state of the engine. A control means for adjusting the capacity to control the air introduction position is provided, and the flow rate control means is controlled to introduce air into both the intake pipe and the exhaust pipe until a predetermined time elapses after the engine is started. , Send air to the exhaust pipe until the catalyst is activated It is obtained by the.

A secondary air introduction control device for an internal combustion engine according to a second aspect of the present invention comprises air introduction amount control means for introducing secondary air to control the introduction amount, and heating means for heating the secondary air. An exhaust introduction pipe connected to introduce air into the exhaust pipe, a backflow preventing means for preventing backflow of exhaust gas into the air introduction passage, and an intake introduction pipe connected to introduce air into the intake pipe. Flow rate control means for varying the passage area of the intake introduction pipe, catalyst activation determination means for determining the activation state of the catalyst, temperature detection means for detecting the catalyst temperature,
And a control means for controlling the air introduction position by adjusting the amount of introduced air and the heating capacity according to the operating state of the engine, and after the catalyst is activated, the intake pipe and the exhaust gas until the catalyst temperature reaches a predetermined temperature. Heating air is introduced into both the pipe and the heating air is introduced only into the intake pipe side when the temperature exceeds a predetermined temperature.

A secondary air introduction control device for an internal combustion engine according to a third aspect of the present invention comprises air introduction amount control means for introducing secondary air to control the introduction amount, and heating means for heating the secondary air. An exhaust introduction pipe connected to introduce air into the exhaust pipe, a backflow preventing means for preventing backflow of exhaust gas into the air introduction passage, and an intake introduction pipe connected to introduce air into the intake pipe. Flow rate control means for varying the passage area of the intake introduction pipe, catalyst activation determination means for determining the activation state of the catalyst, temperature detection means for detecting the catalyst temperature,
Load detecting means for detecting the load state of the engine, acceleration detecting means for detecting the acceleration state, and control means for controlling the air introduction position by adjusting the introduced air amount or heating capacity according to the operating state of the engine. According to the output of at least one of the load detecting means and the acceleration detecting means, the introduction of air into the intake pipe is prohibited.

A secondary air introduction control device for an internal combustion engine according to a fourth aspect of the invention is an air introduction amount control means for introducing secondary air to control the introduction amount, and a heating means for heating the secondary air. An exhaust introduction pipe connected to introduce air into the exhaust pipe, a backflow preventing means for preventing backflow of exhaust gas into the air introduction passage, and an intake introduction pipe connected to introduce air into the intake pipe. Flow rate control means for varying the passage area of the intake introduction pipe, catalyst activation determination means for determining the activation state of the catalyst, temperature detection means for detecting the catalyst temperature,
A control means for controlling the air introduction position by adjusting the amount of introduced air or the heating capacity according to the operating state of the engine, and introducing air into the intake pipe and the exhaust pipe, at least the intake introduction pipe The flow rate control means is controlled so that the amount of flowing air is changed at an arbitrary time interval.

[0016]

According to the first aspect of the present invention, there is provided the intake air introducing pipe for sending the heated air introduced into the exhaust pipe to the intake pipe and the flow rate control means, and the heating air is supplied into the intake pipe until a predetermined time elapses after the engine is started. And by introducing both in the exhaust pipe,
Generally, a lot of fuel is injected and the atomization of the injected fuel can be promoted at a low engine temperature, which is set to be rich, and the combustion performance in the engine can be improved, so that the fuel consumption can be reduced,
It is possible to reduce the emission of HC and CO, which are harmful components. Further, the heated air introduced into the exhaust pipe promotes the oxidation reaction of HC and CO in the exhaust gas, and the generated heat of reaction and the heated air aim at early activation of the catalytic converter to purify the exhaust gas in the catalytic converter. Efficiency can be increased and harmful components emitted into the atmosphere can be reduced.

According to the second aspect of the present invention, the catalytic converter is provided with an intake introduction pipe for sending heated air introduced into the exhaust pipe to the intake pipe, a flow rate control means, and a temperature detection means for detecting the catalyst temperature. After heating, the heated air is introduced into both the intake pipe and the exhaust pipe up to a prescribed temperature, and when the catalyst reaches the prescribed temperature, the introduction of air into the exhaust pipe is prohibited and the heated air is introduced only into the intake pipe side. By doing so, it is possible to prevent damage due to overheating of the catalytic converter, and to prevent the fuel injected from the fuel injection device from adhering to the wall surface of the intake pipe without being atomized. Furthermore, the introduction of heated air into the intake pipe enables lean combustion by promoting fuel atomization,
The fuel consumption amount can be reduced, and the emission amounts of the harmful components HC and CO can also be reduced. Further, until the temperature of the catalyst reaches a predetermined temperature, the catalytic converter promotes the oxidation reaction of HC and CO in the exhaust gas by the heated air introduced into the exhaust pipe to reduce the harmful components discharged into the atmosphere. You can

According to a third aspect of the present invention, in addition to the control device of the second aspect, an engine load detection means and an acceleration detection means are provided, and air to the intake pipe is provided in accordance with the output of at least one of these means. By prohibiting the introduction,
It is possible to prevent torque reduction due to lean combustion during high load operation. Further, the air in the intake pipe is suddenly sucked into the combustion chamber during acceleration, so that the air is diluted, but it is possible to prevent misfire when the air is diluted by the introduction of the secondary air.

According to another aspect of the present invention, the intake air introduction pipe is provided with an intake air introduction pipe for sending heated air introduced into the exhaust pipe to the intake air pipe, a flow rate control means, and a control means for controlling the air introduction position. By controlling the flow rate control means so as to change the amount of flowing heated air at any time interval (hereinafter referred to as modulation), the exhaust gas air-fuel ratio discharged from the engine can be adjusted to any value. You can invert rich / lean at time intervals. Therefore, since the window region where the purification performance of the catalytic converter is maximized is crossed, the concerted adsorption effect of the catalytic converter is obtained and the purification of HC and CO in the exhaust gas is promoted.
Also, by shifting the modulation phase of the modulation introduction air sent to the intake pipe and the exhaust pipe by 180deg, a large amount of exhaust introduction air can be supplied when the exhaust air-fuel ratio is high, and it can be reduced when it is thin, resulting in efficient exhaust Air can be introduced into the pipe. Therefore, HC, C in the exhaust gas by the catalytic converter
It is possible to promote the oxidation reaction of O and reduce harmful components discharged into the atmosphere.

[0020]

【Example】

Example 1. An embodiment of the invention of claim 1 will be described below. FIG. 1 is a block diagram showing the overall structure, FIG. 2 is a timing chart showing control timing, and FIG. 3 is a flow chart for explaining the flow of control. And the description is omitted.

In the figure, 17 is a secondary air adjusting valve for adjusting the air from the air pump 8 to an appropriate amount, which is a mechanical type solenoid which operates a diaphragm by a negative pressure to change the opening degree, or an electromagnetic solenoid. Valves and stepping motor valves are used. The air pump 8 and the secondary air adjusting valve 17 constitute air introduction amount control means. Further, it goes without saying that the air pump 8 is an electric type, and if the pump discharge air amount can be varied by a signal from the outside, the air introduction control means can be configured without using the secondary air adjusting valve 17. . The air from the air introduction amount control means is sent to the heating means.

Reference numeral 18 denotes a heater which, when DC power is supplied, for example, causes a current to flow through the resistor to generate heat. The air heated by the heater 18 is sent to the intake introduction pipe 12 and the exhaust introduction pipe 13. Exhaust gas of 14A is intake pipe 2
A check valve which is a backflow prevention means provided in the middle of the exhaust introduction pipe 13 so as not to backflow into the intake pipe 13 and a flow control valve 11A which is a flow control means for adjusting the amount of air sent to the intake pipe 2.
The heated air sent to the exhaust introduction pipe 13 is sent to the catalytic converter 7 from the air introduction port of the exhaust pipe 6 via the check valve 14A. In addition, the heated air sent to the intake introduction pipe 12 is
The flow rate is controlled by the flow rate control valve 11A and is sent to the intake pipe 2.

Reference numeral 19 is a catalyst activation judging means, for example, an output of a temperature sensor 20 for detecting the temperature of the catalyst carrier is a predetermined value or more, and an inlet gas temperature sensor 21 for detecting the gas temperature of the inlet and outlet of the catalytic converter 7 and an outlet gas. It is determined that the catalyst is activated when the output difference from the temperature sensor 22 is within a predetermined value or when the purification efficiency is obtained from the output of the gas sensor 23 and the efficiency is equal to or higher than the predetermined value. 16A receives signals S1 to S4 from various sensors for detecting the operating state of the engine 1, an air pump 8 as an air introduction control means, a secondary air adjusting valve 17, a heater 18 as a heating means, and a flow rate control means. Is a controller that outputs control signals S5 to S8 to the flow control valve 11A that is

Reference numeral 24 is a crank angle sensor that outputs a rectangular wave having a different cycle according to the rotation of the engine 1, and 25 is a gas sensor, which is used to output a signal according to the oxygen concentration in the atmosphere and the exhaust gas component. There is. These sensors 2
The outputs of Nos. 4 and 25 are sent to the controller 16A and serve as parameters for judging the operating state of the engine 1.

Next, the operation will be described. First, in step 301, the temperature sensor 2 for detecting the catalyst carrier temperature.
Absolute temperature obtained from 0, catalyst inlet gas temperature sensor 21
The catalyst activation determination means 19 detects the activation state of the catalyst from the temperature difference obtained from the catalyst outlet gas temperature sensor 22 and the purification efficiency obtained from the output of the gas sensor after the catalyst. The process moves to step 302 so as to control the introduction of secondary air when activated.

In step 302, signals S5 and S6 are sent from the controller 16A to the air pump 8 and the secondary air regulating valve 17 to start the introduction of air, and further the signal S7 is sent to the heater 18.
To start heating the air. At this time, the air pumps 8 and 2
The amount of air sent from the next air regulating valve 17 and the heating capacity of the heater 18 are determined by the output S1 of the air flow sensor 4 indicating the operating state of the engine 1 and the output of a throttle opening sensor (not shown) of the throttle valve 5. S2 and crank angle sensor 2
The controller 16A obtains an optimum value by receiving the output S3 of No. 4 and the output S4 of the gas sensor 25, and controls the optimum value.

In step 302, the introduction of the heated secondary air is started, a starter signal (not shown) is sent to the controller 16A when the engine 1 is started, and after the start, the starter signal is passed by the value counted by the timer function. Time (T) is required. Next, at step 303, a predetermined time (T1) after the start of intake pipe air introduction, which is determined in advance and stored in the memory, is compared with the post-start elapsed time (T), and the predetermined time (T1) has elapsed. Has
In step 305, the heated air is not introduced into the intake pipe 2 side, but the heated air introduction control is performed only in the exhaust pipe 6.

If the comparison result of step 303 indicates that the time (T) after starting has not reached the predetermined time (T1), step 304 is executed and the control signal S8 for controlling the flow rate control valve 11A is sent to the controller. Intake inlet pipe 1 sent from 16A
2 is released. Therefore, the heated air is introduced into the intake pipe 1
2 is sent to the intake pipe 2 and generally, a large amount of fuel is injected and the atomization of the injected fuel can be promoted at a low engine temperature when the air-fuel ratio is set to be rich, so that the combustion performance in the engine is improved and harmful components are removed. It is possible to reduce the emissions of HC and CO. At this time, the amount of air introduced into the intake pipe 2 is determined and adjusted by the controller 16A so that the air-fuel ratio of the air-fuel mixture supplied into the combustion chamber of the engine 1 becomes 10 to 20% thinner than in the normal state. It The air amount is determined by reading an amount predetermined from the memory depending on the engine temperature and the time after starting, the output of the air flow sensor 4, the output of the gas sensor 25, and the like.

Next, step 305 is carried out, and the heated air is introduced into the exhaust pipe 6 from the exhaust introduction pipe 13 via the check valve 14A. The heated air introduced into the exhaust pipe 6 is mixed with the exhaust gas without lowering the exhaust gas temperature, and the high temperature mixed gas can be sent to the catalytic converter 7, which is a harmful component in the exhaust gas. , CO reacts with CO to promote early activation of the catalytic converter 7 and enhance gas purification efficiency to purify exhaust gas. That is, the mixed gas of exhaust gas and air sent to the catalytic converter 7 contains HC or C
O and the like, and oxygen and the like in the heated air are included. Therefore, in the catalytic converter 7, the high temperature mixed gas is converted into H ₂ O, CO _{2 and the} like by a chemical reaction action to promote purification of the exhaust gas.

Example 2. In the above Example 1, the case where the introduction of the heated air is controlled only in the inactive state of the catalyst has been described. 4 is a block diagram for explaining an embodiment of the invention of claim 2, FIG. 5 is a timing chart showing control timing, and FIG. 6 is a flow chart for explaining the flow of control, which is the same as or equivalent to that of the first embodiment. The same reference numerals are given to the parts and the description thereof will be omitted. In the figure, reference numeral 26 is a cut valve provided in the middle of the exhaust introduction pipe 13, which is a mechanical type valve that operates a diaphragm by negative pressure to change the opening degree, an electromagnetic solenoid valve, a stepping motor valve, or the like. is there.

Next, the operation will be described. First, in step 601, signals S5 and S6 are sent from the controller 16A to the air pump 8 and the secondary air adjusting valve 17 to start the introduction of the secondary air, and further a signal S7 is sent to the heater 18 to start the heating of the air. . Next, in step 602, the catalyst activation determination means 19 detects the activation state of the catalyst, and when the catalyst is inactive, the control described in the first embodiment is performed.
Control proceeds to step 603.

When it is judged in step 602 that the catalyst is in the active state, step 606 is executed, and from the output of the temperature sensor 20 which detects the carrier temperature of the catalytic converter 7,
The absolute carrier temperature (K) of the catalyst is detected by the controller 16A. Then, it is judged whether or not the detected temperature exceeds the catalyst overheat limit predetermined temperature (K1) which is determined in advance and stored in the memory, and if the carrier absolute temperature (K) is equal to or higher than the predetermined temperature (K1), The introduction of heated air into the exhaust pipe 6 is stopped. The air introduction is stopped by the controller 16A through the cut valve 26.
A signal S9 is sent to, and the communication between the exhaust introduction pipe 13 and the heater 18 is cut off. Then, in step 608, the intake pipe 2
Only the air inside will be introduced. Therefore, it is possible to prevent the catalytic converter 7 from being damaged by overheating.

The carrier absolute temperature (K) is a predetermined temperature (K
1) If above, in step 607, the cut valve 26 is opened so that the heated air in the exhaust pipe 6 is introduced, and the heated air is sent to the exhaust introduction pipe 13. Then, in parallel with step 608, the control signal S for controlling the flow rate control valve 11A from the controller 16A so as to introduce the air into the intake pipe 2.
8 is sent and the intake introduction pipe 12 is released. Therefore, it is possible to prevent the heated air from being sent to the intake pipe 2 via the intake introduction pipe 12, and the fuel injected from the fuel injection device not being atomized and adhering to the wall surface of the intake pipe 2. further,
The introduction of the heated air into the intake pipe 2 enables a lean fuel by promoting atomization of the fuel, so that the fuel consumption amount can be reduced. Further, it is possible to reduce the emissions of HC and CO, which are harmful components.

Example 3. In the above embodiment, the case where the heated air is always introduced into the intake pipe 2 after the catalyst activation has been described. However, as shown in FIG. 7, when the throttle valve 5 is suddenly opened and accelerated, the air accumulated in the surge tank (not shown) in the intake pipe 2 is rapidly sucked, so that the air-fuel ratio of the air-fuel mixture is increased. Dilute. Further, when the engine is operated in the rich zone of the high load and high rotation range shown in FIG. 8, generally, fuel is supplied so as to have a rich air-fuel ratio in order to increase the torque, but the intake pipe 2 When air is introduced into the inside, the torque decreases due to lean combustion. Therefore, an embodiment of claim 3 which solves this problem will be described.

The configuration of this embodiment is the same as that of the second embodiment, except that the controller 16A includes an acceleration detection means for newly detecting the acceleration state and a load detection means for detecting the load state of the engine.
In addition, the flow rate control valve 11A is controlled according to the output of at least one of the acceleration detection means and the load detection means. The acceleration detecting means includes, for example, a throttle opening sensor that detects the opening of the throttle valve 5 and an air flow sensor 4. In addition, the load detection means includes the engine 1
There is an air flow sensor 4 for measuring the amount of intake air. Further, the load detecting means detects from the output of the air flow sensor 4 that measures the intake air amount of the engine 1, the boost sensor (not shown) that measures the pressure in the intake pipe 2, and the output of the crank angle sensor 24. The load condition is detected from the engine speed.

Next, the operation will be described. Air pump 8
The air that has been pressurized by and adjusted to the optimum introduction amount by the secondary air adjustment valve 17 is heated by the heater 18, and is sent to the exhaust pipe 6 through the exhaust introduction pipe 13 via the check valve 14A. Further, the heated air adjusted by the flow rate control valve 11A is sent to the intake pipe 2. At this time, if the acceleration detecting means determines that the vehicle is accelerating, or if the load detecting means determines that the vehicle is in a high load state, the controller 16A causes the control signal S8 to set the air passage opening area of the flow control valve 11A to zero. Is sent, and the intake introduction pipe 12 is closed. Therefore, the heated air does not flow through the intake pipe 12 and the intake pipe 2
Will not be introduced to.

Example 4. In the above embodiment, the case where a fixed amount of secondary air is introduced into the exhaust pipe 6 and the intake pipe 2 has been described. An embodiment of the invention of claim 4 in which the introduction of heated air is controlled by modulating the amount of introduced air will be described below. The configuration of this embodiment uses the configuration of the second embodiment, and the controller 16A forcibly drives the flow control valve 11A to modulate the air flowing through the intake introduction pipe 12.
At this time, if the amount of air introduced into the intake pipe 2 is increased and the amount of secondary air discharged from the air introduction amount control means is increased, the amount of introduced air in the exhaust pipe 6 is increased. Is not reduced, but only the introduced air in the intake pipe 2 is modulated. Further, when the amount of air discharged from the air introduction amount control means is fixed, the introduced air in each of the intake pipe 2 and the exhaust pipe 6 is modulated as shown in FIG.
It can be shifted by 80deg.

Next, the operation will be described. Air pump 8
The air that has been pressurized by and adjusted to the optimum introduction amount by the secondary air adjustment valve 17 is heated by the heater 18, and is sent to the exhaust pipe 6 through the exhaust introduction pipe 13 via the check valve 14A. Further, the heated air adjusted by the flow rate control valve 11A is sent to the intake pipe 2. At this time, in order to modulate the amount of air sent to the intake pipe 2, the control signal S8 is sent from the controller 16A to the flow control valve 11A, and the flow control valve 1
The air passage of 1A is forcibly turned ON / OFF, and the flow rate control valve 11A is controlled so that the heated intake air flowing through the intake air introduction pipe 12 changes at an arbitrary time interval.

The modulation cycle (T2) is stored in advance in the memory of the controller 16A, and the ON / OFF duty is 50%. The modulation cycle and duty are corrected according to the engine temperature and the gas sensor output. The amount of increase / decrease in the modulated air amount is determined by the air-fuel ratio in the engine (A
/ F) is 10 to 20% richer / leaner than the theoretical air-fuel ratio. Therefore, the exhaust gas air-fuel ratio discharged from the engine is Rich / lean inversion at arbitrary time intervals. Therefore, since the window region where the purification performance of the catalytic converter 7 is maximized is crossed, the concerted adsorption effect of the catalytic converter 7 is obtained and the purification of HC and CO in the exhaust gas is promoted.

Further, the flow rate control valve 1 is arranged so as to shift the periodic phase of the amount of modulated air sent to the intake pipe 2 and the exhaust pipe 6 by 180 deg.
By controlling 1A, a large amount of secondary air can be supplied when the exhaust air-fuel ratio is rich, and the secondary air is reduced when the exhaust air-fuel ratio is thin, so that the air in the exhaust pipe 6 can be introduced efficiently. HC and CO in the exhaust gas by the catalytic converter 7
Promotes the oxidation reaction of.

Example 5. In the first embodiment, the activation of the catalytic converter 7 is determined based on the output of the catalyst activation determining means. However, the catalyst activation is performed until the count value of the post-start timer reaches a preset predetermined value, that is, when a predetermined time elapses. You may judge that it is becoming. However, the predetermined value is stored in the memory of the controller 16A as a table value based on the engine temperature at the time of starting, the intake air temperature, and the like.

Example 6. In the above embodiment, the check valve 14A
Is installed downstream of the heater 18, but may be provided upstream of the heating means or upstream of the air introduction amount control means as long as the exhaust gas flowing through the exhaust pipe 6 does not flow backward.

Example 7. In the second embodiment, the controller 16A
Although the cut valve 26 is turned on / off in response to the control signal from the control valve, a three-way valve for switching the heating air passage from the outflow of the exhaust introduction pipe 13 to the outflow of the intake introduction pipe 12 is provided in the middle of the exhaust introduction pipe 13. Even if it is provided, the same function as the cut valve 26 can be obtained.

Example 8. In the above embodiment, the controller 16A
Are control signals S1, S2, S indicating the operating state of the engine 1.
3, the air introduction amount control means and the heating means are controlled in response to S3 and S4, but a control signal corrected by various temperatures of the engine 1, battery (not shown) voltage, atmospheric pressure, etc. is output. You may do it. Also, the controller 16A
May be integrated with an engine controller (not shown) that performs fuel injection control, ignition control, rotation adjustment control, etc. of the engine 1.

Example 9. In the above embodiment, the air pump 8
The suction side of is connected to the downstream of the air cleaner 3,
It may be directly sucked from the atmosphere, or a dedicated cleaner may be provided and an inlet port may be provided separately from the intake pipe 2.

[0046]

According to the first aspect of the present invention, the catalyst is activated by controlling the flow rate control means to introduce air into both the intake pipe and the exhaust pipe until a predetermined time has elapsed after the engine is started. Since air is sent to the exhaust pipe up to the exhaust pipe, atomization of the injected fuel can be promoted when the engine temperature is low, and the combustion performance in the engine can be improved, so that the fuel consumption can be reduced and HC and CO Emissions can be reduced. Furthermore, the heated air introduced into the exhaust pipe promotes the oxidation reaction of HC and CO in the exhaust gas, and the reaction heat generated and the heated air aim at early activation of the catalytic converter to purify the exhaust gas in the catalytic converter. There is an effect that efficiency can be increased and harmful components emitted into the atmosphere can be reduced.

According to the second aspect of the present invention, after the catalyst is activated, the heated air is introduced into the intake pipe and the exhaust pipe until the catalyst temperature reaches the predetermined temperature, and when the temperature exceeds the predetermined temperature, only the intake pipe side is introduced. Since the heated air is introduced, it is possible to prevent the catalytic converter from being damaged due to overheating, and to prevent the fuel injected from the fuel injection device from adhering to the wall surface of the intake pipe without being atomized. Further, the introduction of the heated air into the intake pipe enables lean combustion by promoting atomization of the fuel, which can reduce the fuel consumption amount and the emission amounts of harmful components HC and CO. Further, the effect that the heated air introduced into the exhaust pipe after the catalyst activation can accelerate the oxidation reaction of HC and CO in the exhaust gas by the catalytic converter and reduce the harmful components discharged into the atmosphere. There is.

According to the third aspect of the present invention, the introduction of air into the intake pipe is prohibited according to the output of at least one of the load detecting means and the acceleration detecting means. It can prevent the deterioration. Further, the air in the intake pipe is abruptly sucked into the combustion chamber at the time of acceleration to be diluted, but there is an effect that misfiring can be prevented when the dilution is advanced by the introduction of the secondary air.

According to the fourth aspect of the present invention, the flow rate control means is controlled so as to introduce air into the intake pipe and the exhaust pipe and change the amount of air flowing through the intake introduction pipe at an arbitrary time interval. Since it is set to Rich / h at any time interval
ean can be flipped. In order to cross the wind region where the purification performance of the catalytic converter is maximized,
The concerted adsorption effect of the catalytic converter is obtained, and the purification of HC and CO in the exhaust gas is promoted. Further, by shifting the modulation phase of the modulated introduction air sent to the intake pipe and the exhaust pipe by 180 deg, a large amount of the introduced air can be supplied to the exhaust pipe when the exhaust air-fuel ratio is high, and it can be reduced when the air-fuel ratio is thin, resulting in good efficiency. The air in the exhaust pipe can be introduced. Therefore, there is an effect that the catalytic converter can accelerate the oxidation reaction of HC and CO in the exhaust gas and reduce the harmful components discharged into the atmosphere.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of a secondary air introduction control device for an internal combustion engine according to a first embodiment of the present invention.

FIG. 2 is a timing chart illustrating the control timing of FIG.

FIG. 3 is a flowchart illustrating a flow of control operation of FIG.

FIG. 4 is a configuration diagram showing a configuration of a secondary air introduction control device for an internal combustion engine according to a second embodiment of the present invention.

5 is a timing chart illustrating the control timing of FIG.

FIG. 6 is a flowchart illustrating a flow of control operation of FIG.

FIG. 7 shows Embodiment 3 of the present invention and is a diagram showing a Lean spike phenomenon from the relationship between the throttle opening and the air-fuel ratio during acceleration.

FIG. 8 is a diagram showing Embodiment 3 of the present invention and is a diagram showing an enrichment zone in which the air-fuel ratio in the high load / high speed region is set to be high.

FIG. 9 is a diagram showing a relationship between an air amount, a modulation phase, and an engine air-fuel ratio when introducing secondary air modulation according to Embodiment 4 of the present invention.

FIG. 10 is a configuration diagram showing a configuration of a conventional secondary air introduction control device for an internal combustion engine.

[Explanation of symbols]

 1 Internal Combustion Engine 2 Intake Pipe 3 Air Cleaner 6 Exhaust Pipe 7 Catalytic Converter 8 Air Pump 11A Flow Control Valve 12 Intake Inlet Pipe 14A Check Valve 13 Exhaust Inlet Pipe 16A Controller 17 Secondary Air Conditioning Valve 18 Heater 19 Activation Determinator 20 Catalyst carrier temperature sensor 21 Catalyst inlet gas temperature sensor 22 Catalyst outlet gas temperature sensor 23 Gas sensor 24 Crank angle sensor 25 Gas sensor 26 Cut valve

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[Procedure amendment]

[Submission date] February 10, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction content]

The modulation cycle (T2) is stored in advance in the memory of the controller 16A, and the ON / OFF duty is 50%. The modulation cycle and duty are corrected according to the engine temperature and the gas sensor output. The amount of increase / decrease in the modulated air amount is determined by the air-fuel ratio in the engine (A
/ F) is adapted to the theoretical air-fuel ratio becomes 10-20% dense / thin (Rich / L ean). Thus, the exhaust gas air-fuel ratio is discharged from the engine, ∎ it can with Rich / L ean inverted at arbitrary time intervals. Therefore, since the window region where the purification performance of the catalytic converter 7 is maximized is crossed, the concerted adsorption effect of the catalytic converter 7 is obtained and the purification of HC and CO in the exhaust gas is promoted.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0049

[Correction method] Change

[Correction content]

According to the fourth aspect of the present invention, the flow rate control means is controlled so as to introduce air into the intake pipe and the exhaust pipe and change the amount of air flowing through the intake introduction pipe at an arbitrary time interval. Since it was set to Rich / L at any time interval
ean can be flipped. In order to cross the wind region where the purification performance of the catalytic converter is maximized,
The concerted adsorption effect of the catalytic converter is obtained, and the purification of HC and CO in the exhaust gas is promoted. Further, by shifting the modulation phase of the modulated introduction air sent to the intake pipe and the exhaust pipe by 180 deg, a large amount of the introduced air can be supplied to the exhaust pipe when the exhaust air-fuel ratio is high, and it can be reduced when the air-fuel ratio is thin, resulting in good efficiency. The air in the exhaust pipe can be introduced. Therefore, there is an effect that the catalytic converter can accelerate the oxidation reaction of HC and CO in the exhaust gas and reduce the harmful components discharged into the atmosphere.

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Claims (4)

[Claims] 1. In a secondary air introduction control device for an internal combustion engine, which introduces secondary air to the internal combustion engine, air introduction amount control means for introducing secondary air to control the introduction amount, and heating the secondary air. A heating means, an exhaust introduction pipe connected to introduce air into the exhaust pipe, a backflow preventing means to prevent reverse flow of exhaust gas into the air introduction passage, and an exhaust introduction pipe connected to introduce air into the intake pipe. The intake introduction pipe, a flow rate control means for varying the passage area of the intake introduction pipe, a catalyst activation determination means for determining the activation state of the catalyst, and the introduction air amount and heating capacity depending on the operating state of the engine. And a control means for controlling the air introduction position by adjusting the flow rate control means to introduce air into both the intake pipe and the exhaust pipe until a predetermined time elapses after the engine is started. Sends air to the exhaust pipe until is activated Secondary air introduction control apparatus for an internal combustion engine, characterized in that there was Unishi. 2. A secondary air introduction control device for an internal combustion engine, which introduces secondary air to the internal combustion engine, and air introduction amount control means for introducing secondary air to control the introduction amount, and heating the secondary air. A heating means, an exhaust introduction pipe connected to introduce air into the exhaust pipe, a backflow preventing means to prevent reverse flow of exhaust gas into the air introduction passage, and an exhaust introduction pipe connected to introduce air into the intake pipe. The intake introduction pipe, the flow rate control means for varying the passage area of the intake introduction pipe, the catalyst activation determination means for determining the activation state of the catalyst, the temperature detection means for detecting the catalyst temperature, and the operating state of the engine. In accordance with the control means for controlling the air introduction position by adjusting the amount of introduced air and the heating capacity according to the above, after the catalyst is activated, both the intake pipe and the exhaust pipe until the catalyst temperature reaches a predetermined temperature. Introduces heated air to the specified temperature Secondary air introduction control apparatus for an internal combustion engine, characterized in that to perform the introduction of only heating the air intake pipe side exceeds. 3. A secondary air introduction control device for an internal combustion engine, which introduces secondary air to the internal combustion engine, wherein air introduction control means for introducing secondary air to control the introduction amount and heating for heating the secondary air. Means, an exhaust introduction pipe connected to introduce air into the exhaust pipe, a backflow prevention unit to prevent backflow of exhaust gas into the air introduction passage, and an intake air connected to introduce air into the intake pipe An introduction pipe, a flow rate control means for varying the passage area of the intake introduction pipe, a catalyst activation judgment means for judging the activation state of the catalyst, a temperature detection means for detecting the catalyst temperature, and a load state of the engine. Load detecting means, an acceleration detecting means for detecting an acceleration state, and a control means for controlling the air introduction position by adjusting the amount of introduced air or the heating capacity according to the operating state of the engine, the load detecting means And a small number of acceleration detection means Depending on one output Kutomo, secondary air introduction control apparatus for an internal combustion engine according to claim 2, characterized in that so as to prohibit the introduction of air into the intake pipe. 4. In a secondary air introduction control device for an internal combustion engine, which introduces secondary air to the internal combustion engine, air introduction amount means for introducing secondary air to control the introduction amount, and heating for heating the secondary air. Means, an exhaust introduction pipe connected to introduce air into the exhaust pipe, a backflow prevention unit to prevent backflow of exhaust gas into the air introduction passage, and an intake air connected to introduce air into the intake pipe The introduction pipe, the flow rate control means for varying the passage area of the intake introduction pipe, the catalyst activation judgment means for judging the activation state of the catalyst, the temperature detection means for detecting the catalyst temperature, and the operation condition of the engine. And a control means for controlling the air introduction position by adjusting the introduced air amount and the heating capacity, and introducing the air into the intake pipe and the exhaust pipe, at least the air amount flowing through the intake introduction pipe, Change at any time interval As such, the secondary air introduction control apparatus for an internal combustion engine is characterized in that so as to control the flow control means.