JPS5996448A - Control device for intake and exhaust systems of internal-combustion engine - Google Patents

Abstract

PURPOSE:To have sufficient performance of power output and exhaust gas purification compatibly by allowing an exhaust gas feedback control device to reduce the amount of feedback while a fuel increasing device is in service, and by furnishing the exhaust system with a three-dimensional catalyzer converting device. CONSTITUTION:In order to give a mixture gas an air-to-fuel ratio according to the theoretical value during operation, the suction manifold Mi is equipped with a fuel increasing device, which is composed of a fuel increasing valve 61, air bleeder passage 70, No.2 air jet 712 and solenoid operated valve 72, and an exhaust gas feedback device, which is composed of an exhaust gas feedback line 5, feedback amount control valve 6, solenoid operated valve 41 and neg. pressure control valve V. While the fuel increasing device is in service, the amount of exhaust gas feedback shall be reduced. Furnishment of the exhaust system Me with a three-dimensional catalyzer converting device T will provide adjustment of the mixture gas toward Rich when high power is requested as well as reduce the amount of exhaust gas feedback, so that good performance of power output can be obtained and, at the same time, effective purification be made by three-dimensional catalyzer device.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an internal combustion engine of the type that is normally operated with an air-fuel mixture leaner than the stoichiometric air-fuel ratio.

It relates to an exhaust system control device.

Conventionally, as an exhaust gas purification measure for this type of internal combustion engine, an oxidation catalyst conversion device is provided in the exhaust system to purify EC and Co contained in the exhaust gas by causing an oxidation reaction with sufficient oxygen remaining in the exhaust gas. On the other hand, the generation of NOx in the exhaust gas is suppressed by circulating the exhaust gas back into the intake system according to the load of the engine.

By adopting such exhaust gas purification means, the air-fuel ratio of the air-fuel mixture can be maintained at a value leaner than the stoichiometric air-fuel ratio even under high load. This was effective in lightening the load on drivers and reducing fuel consumption, but on the other hand, it was difficult to obtain the desired output performance due to an increase in the amount of exhaust gas recirculation, especially at high loads, and improvements were desired in terms of drivability such as acceleration. It is rare.

Therefore, the present invention normally operates the engine with a lean air-fuel mixture, and when high output is required such as during acceleration, the amount of fuel supplied to the intake system is increased to bring the air-fuel ratio of the air-fuel mixture to approximately the stoichiometric air-fuel ratio. At the same time, it reduces the amount of exhaust gas returned to the intake system,
On the other hand, A'Ox in the exhaust gas, which increases in amount as the mixture becomes richer and the amount of exhaust gas recirculated decreases, can be effectively reduced and purified by installing a three-way catalytic converter in the exhaust system. Of course, it is an object of the present invention to provide an intake/exhaust system control device for an internal combustion engine that can purify IfC and Co at the same time, thereby satisfying both output performance and exhaust gas purification.

Hereinafter, an embodiment in which the present invention is applied to an automobile internal combustion engine will be described with reference to the drawings. The engine E has an intake manifold M6 connected to one side and an exhaust manifold Me connected to the other side, and the upstream end of the intake manifold Mi has a variable A venturi type carburetor C is installed, and this carburetor C is adjusted to produce an air-fuel mixture having an air-fuel ratio leaner than the stoichiometric air-fuel ratio for normal operation of the engine. Further, an air cleaner A is attached to the inlet of the carburetor C.

On the other hand, a three-way catalytic converter T is installed at the downstream end of the exhaust manifold Me.

In the intake path 1 of the carburetor C, a choke valve 2 is installed on the upstream side of the central venturi 1a, and a throttle valve 3 is installed on the downstream side of the central venturi 1a.The venturi 1a has an auxiliary fuel nozzle at its downstream foot. 4a, and the main fuel nozzle 4m at the top.
each opens.

Furthermore, in the intake passage 1, a first negative pressure detection hole D1 is provided near the throttle valve 3, and a second negative pressure detection hole D2 is provided in the venturi 1α.
is opened, and the first negative pressure detection hole D1 is located upstream of the throttle valve 3 at the idle opening position, and
When it starts to open, it moves to the downstream side.

A reflux control valve 6 is provided in the middle. This valve 6 has a diaphragm 8 connected to a two-T dollar-shaped valve body 7 that adjusts the opening degree of the exhaust gas recirculation path 5, and a negative pressure chamber 9 formed above the diaphragm 8, with the valve body 7 being placed on the closing side. The energizing valve spring 10 is compressed to form a negative pressure responsive type.

The negative pressure chamber 9 of the reflux control valve 6 is connected to first and second negative pressure detection holes, first and second negative pressure passages L2 extending from D2, and the first negative pressure A solenoid valve 11 and an orifice 12 located downstream thereof are provided in series in the passage LL. The solenoid valve 11 is the first solenoid valve when the solenoid is energized.
The upper 6-flow side of the negative pressure passage is closed, and the downstream side is communicated with the air opening 13 with a filter.

The second negative pressure passage L2 is provided with a negative pressure control valve r, which is a negative pressure responsive regulating valve V1 that controls opening and closing of the second negative pressure passage L2.
and an air valve V which is also a negative pressure responsive type and controls the regulating valve V1 by receiving feedback of the operating negative pressure of the recirculation M2 control valve 6.
The structure of the joint venture will be explained in sequence.

First, the regulating valve V has a valve chamber 20 formed in the middle of the second negative pressure passage L2, a negative pressure chamber 22 adjacent to the upper side of the valve chamber 20 via a diaphragm 21, and a valve chamber 20 attached to the diaphragm 21. The flat valve body 23 is configured to open and close the downstream valve port 25 of the negative pressure passage L1, and a valve spring 24 biases the valve body 23 toward the closing side.

Next, the air valve V2 includes a valve chamber 30 formed in the middle of a control intake path extending from the intake manifold M i and reaching the filtered atmosphere opening 14, and a diaphragm 3 above the valve chamber 30.
Negative pressure chamber 32 adjacent through 1 and the diaphragm 3
The flat valve body 33 attached to the control intake passage L3 is attached to the control intake passage L3 and can open and close the valve port 35 on the downstream side of the control intake passage L3, and a valve spring 34 biases the valve body 33 toward the closing side.

Thus, the negative pressure chamber 32 has a communication passage 36 and regulating valves f, r,
It communicates with the negative pressure chamber 9 of the recirculation amount control valve 6 via the second negative pressure passage L2 downstream of the valve port 25 of.

The negative pressure chamber 22 of the regulating valve V1 is connected to the valve chamber 3 of the air valve V2.
A pair of orifices J1 are formed so as to intervene in the control intake passage L3 upstream of 0, and sandwich this negative pressure chamber 22 between them.
, J2 are provided in the control intake passage L3, and their throttle openings are the same, or the upstream one J and the downstream one J2
is set smaller.

Further, an orifice 40 and a solenoid valve 41 are arranged in series in the second negative pressure passage L2 on the upstream side of the regulating valve V. This solenoid valve 41 is connected to the second negative pressure passage L when the solenoid is energized.
The upstream side of 2 is closed, and the downstream side is communicated with the air opening 14 with a filter.

A secondary air passage L4 extending from the air cleaner A is connected to the exhaust manifold Me just before the three-way catalytic converter 7°, and a silencer 50 is connected to the secondary air passage L4 from the upstream side (air cleaner A side). , a negative pressure responsive valve 51 and a reed valve 52 are successively installed in series. The negative pressure responsive valve 51 includes a valve body 53 that opens and closes the inlet of the reed valve 52, a diaphragm 54 that supports the valve body 53, a negative pressure chamber 55 formed on one side of the diaphragm 54, and a negative pressure chamber 55 formed on one side of the diaphragm 54. It is composed of a valve spring 56 that is contracted in the chamber 55 and springs the diaphragm 54 in the closing direction of the valve body 53, and when a negative pressure of a predetermined value or more is introduced into the negative pressure chamber 55, the diaphragm 54 is operated to open the valve body 53. A third negative pressure passage branched from the control intake passage L3 is connected to the negative pressure chamber 55.

A solenoid valve 5.7 is interposed in this negative pressure passage.

The solenoid valve 57 passes through the third negative pressure passage when the solenoid is energized,
When the upstream side of the filter is closed, the downstream side is communicated with the filtered atmosphere opening port 58.

In the present invention, the upstream side of the negative pressure passage refers to the negative pressure source side.

As shown in FIG. 2, the auxiliary fuel nozzle 4a of the carburetor C includes first and second fuel jets (first and second fuel jets) 60. ．． 60
2 and a fuel increase valve 61 provided directly below the second fuel jet 602 to communicate with the surface of the fuel oil in the float chamber 62 .

The fuel increase valve 61 includes a valve cylinder 63 connected to the lower part of the second fuel jet 602, and a needle valve that is housed in the valve cylinder 63 so as to be able to rise and fall and cooperates with a valve seat 63d10- at the lower end of the valve cylinder 63. 64, a valve spring 65 that springs the needle valve 64 toward the valve seat 63d, an actuator 66 that can come into contact with the protrusion of the needle valve 64 that passes through the valve seat 63α, and the bottom of the flow/stand chamber 62. A diaphragm 67 that is stretched on a wall and supports the actuator 66, a negative pressure chamber 68 formed outside the diaphragm 67, and a spring force that is compressed in the negative pressure chamber 68 and is stronger than the valve spring 65. and a return spring 69 that springs the actuator 66 in the opening direction of the needle valve 64.
is communicated with the intake manifold Mi via a fourth negative pressure passage L6.

Therefore, during low load operation of the engine in which the throttle valve 3 is placed in a low opening range, relatively high negative pressure generated downstream of the throttle valve 3 is transmitted to the negative pressure chamber 68 through the fourth negative pressure passage L6. Then, the actuator 66 is pulled down together with the diaphragm 6γ against the force of the return spring 690, so the needle valve 64 is lowered by the force of the valve spring 65 and seats on the valve seat 63α, thereby closing the fuel increase valve 61. . Therefore, during low-load operation, the amount of fuel supplied from the float chamber 62 to the auxiliary fuel nozzle 4a is measured to a small extent only by the first fuel jet 601, so that the amount of fuel ejected from the auxiliary fuel nozzle 4a is relatively small. On the other hand, during high load operation of the engine in which the throttle valve 3 is placed in a high opening range, the negative pressure in the negative pressure chamber 68 also decreases as the negative pressure downstream of the throttle valve 3 decreases, and the return spring 69 Since the actuator 66 is pushed up together with the diaphragm 67, the actuator 66 separates the needle valve 64 from the valve seat 63α and opens the fuel increase valve 61.

Therefore, during high-load operation, the amount of fuel supplied from the float chamber 62 to the auxiliary fuel nozzle 4a is metered in parallel by the first and second fuel jets 6o+ and 602, so that the fuel is injected from the auxiliary fuel nozzle 4a. The amount will be increased.

Returning to FIG. 1 again, an air bleed passage 70 is connected to the auxiliary fuel nozzle 4a, and this air bleed passage 70
communicates with the air cleaner A via the parallel first and second air jets γ1 and 112, and the second air jet 71
A solenoid valve 72 is provided in the communication path between □ and the air cleaner A.

Therefore, if the electromagnetic valve 72 is not energized and is in the open state, the amount of bleed air supplied from the air cleaner A to the auxiliary fuel nozzle 4a is equal to the amount of air supplied from the first and second air jets 71+ in parallel.
, 712, the amount of air mixed into the fuel in the auxiliary fuel nozzle 4a increases, and as a result, the amount of oil injected from the auxiliary fuel nozzle 4a is controlled to be small.

On the other hand, when the solenoid valve 72 is energized and becomes closed, the second air jet 712 is closed, and the amount of bleed air supplied from the air cleaner A to the auxiliary fuel nozzle 4a is reduced by only the first air jet 711. Therefore, the amount of air mixed with the fuel in the auxiliary fuel nozzle 13-4α decreases, and as a result,
This also increases the amount of oil supplied from the auxiliary fuel nozzle 4a.

The following control system for the four electromagnetic valves 11, 41, 57, and 72 is prepared.

First load detector S1...outputs a high 7 bell signal when the engine E is under high load, for example when the boost wJJ''80mmE'y or less.

Vehicle speed detector □...Predetermined low vehicle speed range, for example, when the vehicle speed is 1
Outputs a high level signal when the speed is below 5 or 30 M/h.

First engine temperature sensor S3...predetermined low temperature range of engine E,
For example, when the cooling water temperature of engine E is below 65 or 70°C, a high level signal is output.

Engine speed detector S4... below the predetermined rotation speed of the engine E,
For example, when the frequency is 3150 γpm or less, a high to 14-bell signal is output.

2nd load detector S, ・When engine E is idling or decelerating, for example, boost negative pressure is 5307H7J g
When J-, a high level signal is output.

2nd engine temperature detector S6...High 17 when the predetermined low temperature range of the engine E, for example, the cooling water temperature of the engine L" is 50'C or less
Outputs a bell signal.

Joint detector, 57...Detects information such as vehicle speed, engine speed, boost negative pressure, etc., and outputs a high level signal under predetermined conditions.

The outputs of the first load detector S and the vehicle speed detector S2 are the first O
R circuit 731C is input, and the outputs of engine temperature sensor 5° and engine speed sensor 454 are A N f) circuit 74
is input. The outputs of the second load detector S and the second engine speed detector 56 are input to the second OR circuit 75, and the output of the composite detector 57 is input to the third AIV/) circuit 76.

The output of the first OR circuit 73 is input to the solenoid valve 41 and the solenoid valve 72, and the output of the AND circuit 74 is input to the third OR circuit 76,
and is input to the first-OR circuit 73 as necessary, and the second
The output of the 0R circuit 75 is input to the solenoid valve 11, and the output of the third (JR) circuit 76 is input to the solenoid valve 57.

Next, to explain the operation of this embodiment, the solenoid valve 11.
41 is in a de-energized state as shown in the figure. Therefore, when the negative pressure generated near the throttle valve 3 due to the operation of the engine E is detected by the first negative pressure detection hole, the negative pressure p
c is transmitted to the negative pressure chamber 32 of the air valve V2 via the solenoid valve 11 and the orifice 12, and when it overcomes the set load of the valve spring 34, the valve body 33 is pulled up via the diaphragm 31, and the control intake path L3 conduction.

When the control intake path becomes conductive, outside air is sucked into the atmosphere opening port 14, and the flow rate is regulated by the orifices J, , J2 before and after the negative crown 22 of the regulating valve V, and then the air valve V2
The air is sucked into the intake passage of the engine E through the valve chamber 3o and the valve port 35. Accordingly, negative pressures P1 and P2 are generated in the negative pressure chamber 22 of the regulating valve V and the valve chamber 30 of the air valve V2, respectively, and the negative pressure ratio is determined by the throttle ratio of the orifice J, J2. .

Thus, in the regulating valve V1, the negative pressure P in the negative pressure chamber 22,
If the upward force of the diaphragm 21 due to the differential pressure between the negative pressure P IJ and the detected negative pressure P IJ of the second negative pressure detection hole D2 overcomes the set load of the valve spring 24, the valve body 23 is pulled up via the diaphragm 21, Since it is opened, a part of the negative pressure Pυ flows into the valve port 25.
The negative pressure that previously passed through the orifice 12 is diluted into negative pressure pe, which acts on the negative pressure chamber 9 as the operating negative pressure of the reflux control valve 6.

According to the above-mentioned dilution of the negative pressure, a decrease in the operating negative pressure pe is fed back to the negative pressure chamber 32 of the air valve V2 through the communication passage 36, and the negative pressure in the chamber 32 is decreased.

Accordingly, the valve port 35 of the air valve V2 is rapidly shut off by the valve body 33, so the negative pressure P1 in the negative pressure chamber 22 and the negative pressure P2 in the valve chamber 30 decrease, and accordingly, the valve body 23 closes to the valve body 33. Close mouth 25. Then, the negative pressure pe rises in operation 18, and the pressure is fed back to the air valve V2, causing the valve element 23 to open the valve port 25 by the opposite action to the above, and the same action is repeated, and this repetition is extremely Since this is done quickly, a constant pressure ratio equal to the pressure ratio of negative pressures P1 and P2 can be given to negative pressures Pυ and P'C.

Therefore, if the intake air amount of the engine E is small, the negative pressure P is higher than the negative pressure pv, so the valve body 23 of the regulating valve V is located on the open side, and the operating negative pressure pe of the recirculation amount control valve 6 is On the other hand, when the amount of intake air increases, the negative pressure pv increases, the valve body 23 moves to the closing side, and the operating negative pressure pe increases. As a result, the air valve V2 has its open state time and closed state time controlled according to the negative pressure pe, and the recirculation amount control valve 6
Since the opening area of is controlled by the same negative pressure pe, the amount of air flowing through the controlled intake passage L3 and the amount of exhaust gas recirculation are substantially proportional, and the amount of intake air and the amount of exhaust gas recirculation of the engine E are proportional,
The exhaust gas can be sucked into the engine E at a constant recirculation rate, and the exhaust gas recirculation rate is determined in advance by the pressure ratio between Pυ and pe, and therefore by the throttling ratio of the orifices J, J2.

Here, the engine E enters a high load operating state and the first load detector S1 issues a high level signal, the vehicle speed is relatively low and the vehicle speed detector S2 issues a high level signal, or the engine temperature is relatively low. The engine rotation speed is lower than the predetermined rotation speed, and the first engine speed detector S3 and the engine speed detector S4
If both of them emit high level signals, the first OR circuit 7
3, a high level signal is simultaneously input to the solenoid valve 72 and the solenoid valve 41, making them energized.

When this electromagnetic valve 72020 is energized, the second air jet 712 in the air bleed passage 70 of the auxiliary fuel nozzle 4a is closed as described above, so that the amount of fuel jetted from the fuel nozzle 4a is increased and the intake passage 1 is The air-fuel ratio of the generated air-fuel mixture is corrected to approximately the stoichiometric air-fuel ratio, and the engine E receives this air-fuel mixture and increases its output. When the load further increases, the fuel increase valve 61 operates as described above to increase the amount of fuel jetted from the auxiliary fuel nozzle 4α, thereby increasing the output of the engine.

On the other hand, when the solenoid valve 410 is energized, the downstream side of the second negative pressure passage L2 communicates with the atmosphere opening port 14 as described above.
Since the valve chamber 20 of the regulating valve V is maintained at atmospheric pressure and the valve body 23 is positioned on the open side, the operating negative pressure pe decreases and the opening degree of the recirculation amount control valve 6 decreases, resulting in an increase in the exhaust recirculation rate. decreases,
Contributes to increasing engine output.

Engine E enters the idle link state or deceleration state and
When the load sensor S issues a high level signal, or when the engine temperature is relatively low and the second engine temperature sensor S6 issues a high level signal, the second OR circuit 21-75 outputs a high level signal to the solenoid valve 11. A high level signal is input to the circuit, turning it on.

By energizing the solenoid valve 11, the downstream side of the first negative pressure passage L1 is communicated with the atmosphere opening port 13 as described above.
The operating negative pressure pe becomes atmospheric pressure, the recirculation amount control valve 6 is closed, and the recirculation of exhaust gas can be stopped.

During operation of the engine E, the exhaust gas discharged to the exhaust manifold ()fe passes through a three-way catalytic converter, and at this time, HC, Co, and NOx contained in the exhaust gas are purified.

By the way, the three-way catalytic converter T exhibits a good purification function for all EC, Co, and NOx when the air-fuel ratio of the gas is approximately the stoichiometric air-fuel ratio, but when the air-fuel ratio is less than the stoichiometric air-fuel ratio, If the air-fuel ratio becomes too lean, the NOx purification function will be significantly reduced, and if it becomes richer than the stoichiometric air-fuel ratio, the HC
, Co has the property of significantly reducing its purifying function for Co.

Therefore, during normal operation in which engine EIJ''-specially high output is not required, the generation of N(J)x is suppressed by combustion of a lean mixture, and HC and C0 in the exhaust gas are purified by the three-way catalytic converter T. As a result, I in the exhaust gas
It is possible to keep the concentrations of IC, CO, and NOx low.

Furthermore, when the engine E is operated to require high output, the amount of NO4γ generated increases due to the combustion of a rich air-fuel mixture with a nearly stoichiometric air-fuel ratio. Since it works effectively, the concentration of the above three components in the exhaust gas can be kept low in this case as well.

In addition, when the air-fuel mixture is enriched for acceleration when engine E is at a low temperature, at the beginning of deceleration, and when changing gears, especially JfC,
The CO concentration increases, but in such a case, in the illustrated example:
Both the first engine speed detector S3 and the engine speed sensor S4 generate high level signals, which are input to the solenoid valve 57 via the A N I) circuit 74 and the third OR circuit 76,
The composite detector S7 generates a high level signal, which is also input to the solenoid valve 57 via the third OR circuit 76, thereby energizing the solenoid valve 57. According to the energization of this electromagnetic valve 5γ, the boost negative pressure of the engine passes through the control intake passage L3 and the third negative pressure passage L5 to the negative pressure chamber 55 of the negative pressure responsive valve 51.
The suction force opens the valve body 53 via the diaphragm 54. Then, due to the exhaust pulsation in the exhaust system and the accompanying opening/closing action of the reed valve 52, air in the air cleaner A is supplied into the exhaust manifold Afe through the secondary air passage L4, thereby increasing the air-fuel ratio of the exhaust gas. Since the air-fuel ratio is corrected to approximately the stoichiometric air-fuel ratio, the purification function of the three-way catalytic converter T is fully exhibited even in such a case.

FIG. 3 shows a second embodiment of the present invention, which differs from the previous embodiment in the means for adjusting the exhaust gas recirculation rate, and only the differences will be described.

Orifice J1 and atmosphere opening port 14 of control intake path L3
A normally open solenoid valve 90 is interposed in the section connecting the two, and a bypass path 91 that substantially bypasses this solenoid valve 90 is provided.
is connected, and an orifice J3 is thrown into this bypass path 91. The output of the first OR circuit γ3 is input to the solenoid valve 90. Since such a solenoid valve 90 is provided, there is no need to provide the solenoid valve 41 in the second negative pressure passage L2 as in the previous embodiment.

Other configurations are the same as those in the previous embodiment, and parts in FIG. 3 that correspond to those in FIG. 1 are given the same reference numerals.

Therefore, the flow resistance of the control intake passage L3 from the atmosphere opening port 14 to the regulating valve V is the same when the solenoid valve 90 is open (when not energized).
Orifice J3 is disabled from 25- to orifice J1, and solenoid valve 90
When the valve is closed (that is, when the first OR circuit 73 also receives a high level signal and is energized), the orifice 'I+J3 connected in series
Each is greatly adjusted by If the flow path resistance is adjusted to a large value, the ratio between the negative pressures P1 and P2, and therefore the ratio between the negative pressures Pυ and pe, changes so as to reduce the exhaust gas recirculation rate.

In the above, the carburetor C and the intake manifold Mi constitute the intake system of the engine E, the exhaust manifold Afe constitutes the exhaust system, and the fuel increase valve 61, the air bleed passage 70, the second air jet 71.2, and the exhaust manifold Afe constitute the exhaust system. The solenoid valve 72 constitutes a fuel increase device, and the exhaust gas recirculation path 5, the recirculation amount control valve 6, the negative pressure control valve V, and the solenoid valve 41 constitute an exhaust gas recirculation device.

As described above, according to the present invention, the intake system includes a fuel increasing device capable of increasing the amount of fuel supplied to the intake system so that the air-fuel ratio of the air-fuel mixture during operation becomes approximately the stoichiometric air-fuel ratio; An exhaust gas recirculation device capable of controlling the amount of exhaust gas recirculated to the intake system is provided, and when the fuel increase device is activated, the exhaust gas recirculation control device operates to reduce the amount of exhaust gas recirculated. is equipped with a three-way catalytic conversion device, so when high output performance is required, the fuel increaser and exhaust gas recirculation device operate together to enrich the air-fuel mixture and reduce the amount of exhaust gas recirculation. Output performance can be obtained. As the air-fuel ratio at this time is approximately the stoichiometric air-fuel ratio, not only NOx but also HC and Co in the exhaust gas, which increases due to this, are effectively purified by the three-way catalytic converter, and these emissions are reduced. The concentration can be kept low, and therefore both output performance and exhaust gas purification can be satisfied.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a schematic overall view of the first embodiment, and FIG. FIG. 2 is a schematic overall view of the second embodiment. E... Internal combustion engine, C, Mi... Intake system, C... Carburetor, Mi... Intake manifold, Me...
・Exhaust manifold that constitutes the exhaust system, 61.70,7
12. 72... Fuel increase device, 61... Fuel increase valve, 70... Air bleed passage, 71□... Second air jet, 72... Solenoid valve, 5.6, 41. V...Exhaust gas recirculation device, 5...Exhaust gas recirculation path, 6...Recirculation amount control valve, 41...Solenoid valve, V...Negative pressure control valve

Claims (1)

[Claims] (1) In an internal combustion engine that is normally operated with an air-fuel mixture having an air-fuel ratio leaner than the stoichiometric air-fuel ratio, the intake system is designed to maintain the air-fuel ratio of the air-fuel mixture at approximately the stoichiometric air-fuel ratio during operation. A fuel increasing device that can increase the amount of fuel supplied to the intake system and an exhaust gas recirculation device that can control the amount of exhaust gas recirculated to the intake system are provided, and when the fuel increasing device is activated, the exhaust gas recirculation control device is provided. An intake/exhaust system control device for an internal combustion engine, which operates to reduce the amount of recirculation of exhaust gas and includes a three-way catalytic conversion device in the exhaust system. (2) The internal combustion engine according to claim (1), wherein the fuel increase device and the exhaust gas recirculation device are configured to operate upon detecting a predetermined high load state of the engine. (3) The device described in claim (1) (in C, the fuel increase device and the exhaust gas recirculation device operate by detecting a predetermined low speed region of the vehicle). An intake, J, and I gas system control device for an internal combustion engine configured as follows. An intake/exhaust system control device for an internal combustion engine, which is configured to operate by detecting a predetermined low temperature region. (5) In the device described in claim (1),
The fuel increase device and the exhaust gas recirculation device are configured to operate when detecting that the engine is in a predetermined low temperature range and is operated at a predetermined rotation speed or less.
Exhaust system control device.