JPS59226255A - Control apparatus for internal-combustion engine - Google Patents

Abstract

PURPOSE:To stabilize operation of an engine and to increase the output of the same, by providing an ignition timing control means for restricting the advance angle limit of the ignition timing according to the operational conditions of a fuel increasing means in an internal-combustion engine which is operated at an air-fuel ratio providing lean air-fuel mixture. CONSTITUTION:A fuel increasing means is constructed to increase fuel supplied from a second fuel jet 602 when a valve 64 is opened by a diaphragm 65 and a return spring 67 disposed in a vacuum chamber 66 of a fuel increasing valve 61 as the negative intake pressure is lowered at the time of high-load operation of an engine. Further, in an ignition distributor 50 for advancing or delaying the igniton timing by displacing a control rod 51, an ignition timing control means 52 is connected to the control rod 51. The ignition timing control means 52 is so designed that the advance angle of the ignition timing is set at a first limit when the engine temperature is low and a temperature-sensitive valve 11 is communicated with the atmosphere or when the engine temperature is high, the temperature-sensitive valve 11 is communicated with a negative-pressure passage L1, and the engine load is low. On the other hand, the advance angle is set within a second limit at the time of high-load operation of the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for 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.

Conventionally, in the above-mentioned type of internal combustion engine, the air-fuel ratio of the air-fuel mixture was enriched to approximately the stoichiometric air-fuel ratio depending on the operating conditions in order to stabilize combustion and improve output performance.
However, there is still room for further improvement in terms of fuel efficiency, drivability, etc.

The present invention provides an effective control device for the internal combustion engine that can achieve such improvements, and its feature is to adjust the air-fuel ratio of the air-fuel mixture to approximately stoichiometric depending on the low temperature state or high load state of the engine. A fuel increasing device that operates to increase the amount of fuel supplied to the intake system in order to enrich the fuel ratio, and regulating an ignition timing advance limit to a first limit when the fuel increasing device is activated and to the first limit when the fuel increasing device is not activated. The ignition timing control device is provided with an ignition timing control device that interlocks with the fuel increase device so as to regulate the fuel amount to a second limit that is advanced from the limit of the ignition timing control device.

An embodiment in which the present invention is applied to an automobile internal combustion engine will be described below with reference to the drawings. First, in FIG. 1, an intake manifold M B is connected to the cylinder head side of the engine E, and an exhaust manifold A/e is connected to the other side. A carburetor C is installed at the upstream end of the intake manifold Mi, and the carburetor C is adjusted to produce an air-fuel mixture with an air-fuel ratio leaner than the stoichiometric air-fuel ratio during normal operation of the engine. Further, an air cleaner A is attached to the inlet of the carburetor C.

On the other hand, an exhaust purification device T is attached to an exhaust pipe connected to the exhaust manifold Ale.

In the intake path 1 of the carburetor C, a choke valve 2 is installed on the upstream side and a throttle valve 3 is installed on the downstream side of the central venturi 1J1a, and a fuel nozzle 4 is opened in the venturi 1α.

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

An exhaust gas recirculation path 5 branching and extending from the exhaust manifold Δie of the engine E is connected to the intake manifold M i, and a recirculation amount control valve 6 is provided in the middle thereof. This valve 6 has a diaphragm 8 connected to a valve body 7 that adjusts the opening degree of the exhaust gas recirculation passage 50, and a valve spring that urges the valve body 7 toward the closing side in a negative pressure chamber 9 formed above the diaphragm 8. 1
0 is shortened to form a negative pressure responsive type.

First and second negative pressure passages extending from first and second negative pressure detection holes D1 and D2 are connected to the negative pressure chamber 9 of this return amount control valve 6, and the first negative pressure passage L1 is provided with a temperature-sensitive valve 11 and an oriice Jθ located downstream thereof in series. The temperature-sensitive valve 11 closes the upstream side of the first negative pressure passage L1 when the engine temperature is lower than a predetermined engine temperature (for example, 70C in terms of cooling water temperature), and communicates the downstream side with the atmosphere opening port 13 with a film, and when the temperature exceeds the predetermined temperature, the temperature-sensitive valve 11 closes the upstream side of the first negative pressure passage L1. It operates to make the first negative pressure passage L1 conductive and to close the atmosphere opening port 13.

The second negative pressure passage L2 is provided with a negative pressure control valve V, which includes a negative pressure responsive regulating valve V that controls opening and closing of the second negative pressure passage L2;
and an air valve V2 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 amount control valve 6.The configuration of the six valves will be explained in sequence.

First, the regulating valve V1 includes 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 through a diaphragm 21, and a first negative pressure chamber attached to the diaphragm 21. It is composed of a valve body 23 that can open and close a downstream valve port 25 of the passage, and a valve spring 24 that 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 passage LC extending from the intake manifold Mi and reaching the filtered atmosphere opening 14, and a diaphragm 31 above the valve chamber 30.
The adjacent negative pressure chamber 32 and the diaphragm 31
The valve body 33 includes a valve body 33 that is attached to the control intake passage LC and can open and close a valve port 35 on the downstream side of the control intake passage LC, and a valve spring 34 that biases the valve body 33 toward the closing side. Thus, the negative pressure chamber 32 is connected to the communication passage 36 and the second valve downstream of the valve port 25 of the regulating valve V.
It communicates with the negative pressure chamber 9 of the reflux control valve 6 via the negative pressure passage L2.

The negative pressure chamber 22 of the regulating valve V1 is the valve chamber 30 of the air valve V2.
A pair of orifices J, , J are formed so as to intervene in the control intake passage LC at the upstream side of the
2 are provided in the control intake passage LC, and their throttle opening degrees are set to be the same, or the one on the upstream side J is set smaller than the one on the downstream side 12.

Further, an orifice J3 is provided in the second negative pressure passage L2 on the upstream side of the regulating valve V1, and a first electromagnetic valve Vs is provided between the orifice J3 and the regulating valve V1.

A first relief passage Ll leading to is connected.

In the carburetor C, the fuel nozzle 4 controls the fuel oil level in the float chamber 62 via the parallel first and second fuel jets 60+, 602 and a fuel increase valve 61 provided directly below the second fuel jet 60□. It connects to the bottom. Fuel increase valve 6
1 includes a valve cylinder 63 connected to the lower part of the second fuel jet 602, and a valve cylinder 6 that is housed in the valve cylinder 63 so as to be movable up and down.
3. A valve body 64 that cooperates with the valve seat at the lower end, and a diaphragm 65 that is stretched over the bottom wall of the float chamber 62 and connected to the valve body 64.
and a negative pressure chamber 6 formed outside this diaphragm 65.
6, and a return spring 67 that is contracted in the negative pressure chamber 66 and urges the diaphragm 65 in the opening direction of the valve body 64.The negative pressure chamber 66 has a third negative pressure passage L3 in the intake manifold AIi. communicated via.

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 66 through the third negative pressure passage L3. However, since the diaphragm 65 is pulled down against the force of the return spring 67,
The valve body 64 descends and seats on the valve seat of the valve cylinder 63, closing the fuel increase valve 61. Therefore, during low load operation, the amount of fuel supplied from the float chamber 62 to the fuel nozzle 4 is measured to a small extent only by the first fuel jet 601, so that the amount of fuel ejected from the fuel nozzle 4 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 66 also decreases as the negative pressure downstream of the throttle valve 3 decreases, and the return spring 67 Since the diaphragm 65 is pushed up, the valve body 64 is separated from the valve seat, and the fuel increase valve 61 is opened. Therefore, during high-load operation, the amount of fuel supplied from the float chamber 62 to the fuel nozzle 4 is set to the first and second fuel jets (60) in a parallel relationship.
．． ．． 602, the fuel nozzle 4 is metered in winter.
The amount of fuel ejected from is increased. In the above, the second fuel jet 602 and the fuel increase valve 61 constitute the fuel increase device of the present invention.

A temperature-sensitive valve 40 and an orifice J4 located upstream of the temperature-sensitive valve 40 are interposed in series in the third negative pressure passage L3. The temperature-sensitive valve 40 operates at a predetermined engine temperature (for example, a cooling water temperature of 50C).
), the third negative pressure passage L3 is shut off, and above that temperature, the third negative pressure passage L3 operates to be conductive. L12 is connected. Further, a common relief passage Llc connected to the atmosphere opening port 13 is connected to the first solenoid valve 11s.

In the demagnetized state, the first solenoid valve VS1 includes a first relief passage Ll,
In the energized state, the second relief passage L12 is shut off and the first relief passage L1 is communicated with the common relief passage Llc.

The engine E is equipped with a known ignition power distributor 5o, and this power distributor 50 can advance the ignition timing by moving the operating rod 51 to the left in the figure, and can retard the ignition timing by moving it to the right. can.

An ignition timing control device 52 for controlling the operating rod 51 is connected to the operating rod 51. This device 52 has a fixed housing 5
3, the housing 53 has a first negative pressure chamber formed by a first diaphragm 541 coupled to the operating rod 51 and a second diaphragm 542 facing the first diaphragm 541 on the opposite side from the operating rod 51. 55. However, a second negative pressure chamber 552 is defined by the second diaphragm 542 and the left end wall of the housing 53. A stopper wall 56, which is integral with the housing 53, is disposed between the two diamonds 77m 54+, 542, and the first diaphragm 54. A stopper pin 57 facing the second diaphragm 542 is fixed to the second diaphragm 542. This stopper pin 57 connects to the first diaphragm 54. The second diaphragm 54 controls the leftward movement of
A first limit is provided in the forward position where the second diaphragm 54 is in contact with the stopper wall 56, and a second limit is provided which is further advanced than the first limit in the retracted position where the second diaphragm 54 is separated from the stopper wall 56. First negative pressure chamber 55. has a first diaphragm 54. A spring 58 springs the second diaphragm 542 in the retard direction, and a second diaphragm 542 is connected to the stopper wall 56 in the second negative pressure chamber 552.
A spring 59 that springs toward is compressed.

The first and second negative pressure chambers 55□, 55□ have fourth and fifth negative pressure chambers.
Negative pressure passages L4 and L5 are connected to each other.

The fourth negative pressure passage L4 extends from the control intake passage Lc between the intake manifold Aft and the air valve 12.

At the upstream end of the fifth negative pressure passage L5, an intake manifold Mi
and a sixth negative pressure passage L6 extending from the control intake passage LC between the temperature-sensitive valve 11 and the orifice 12;
A seventh negative pressure passage L7 extending from the negative pressure passage L1 is a second
It is connected via a solenoid valve VS2. The second solenoid valve V82 shuts off the sixth negative pressure passage L6 in a demagnetized state and
Negative pressure passage L5. L7 are communicated with each other, and in the excited state, the seventh negative pressure passage L7 is shut off and the fifth and sixth negative pressure passages are connected.6. LLI
It works to communicate between the two.

As shown in FIG. 2, the solenoid of the solenoid valve VSI is connected to a battery 73 via parallel first and second circuits 70, 71 and an ignition switch 72. value (e.g. 20 Km/A)
A first vehicle speed detection switch Sυ1 that closes when the speed exceeds the specified speed, a load detection switch SL that closes when the engine E enters a predetermined low load state, and a second electromagnetic valve VS2 that closes from the load detection switch St.
A diode 74 whose forward direction is directed toward the solenoid is inserted in series, and the second circuit 71 has a second diode 74 that closes when the vehicle speed exceeds a predetermined high speed value (for example, 50 Kml).
Vehicle speed detection switch Sυ2 is inserted. A second solenoid valve f1. ．． 2 solenoids are connected.

The load detection switch SL is configured to be a negative pressure responsive type that detects an increase in the pull stroke negative pressure of the engine E by detecting a decrease in its load. That is, in order to introduce the boost negative pressure of the engine E into the negative pressure chamber 75, an eighth negative pressure passage L8 (see FIG. 1) is branched from the control intake passage LC between the intake manifold M i and the air valve 12. is connected.

Next, the operation of this embodiment will be explained.

When the engine temperature is relatively low, the temperature-sensitive valve 40 blocks the third negative pressure passage L3, so the negative pressure chamber 66 of the fuel increase valve 61 is connected to the intake manifold Af i Negative pressure inside is not transmitted. As a result, the diaphragm 65 is displaced upward by the elastic force of the return spring 67 and opens the valve body 64, so that the amount of fuel jetted from the fuel nozzle 4 is increased as described above, and the amount of fuel ejected from the intake passage 1 is increased. The air-fuel ratio of the filtered air-fuel mixture is enriched to a substantially stoichiometric air-fuel ratio suitable for warm-up operation of the engine E, that is, an air-fuel ratio that is slightly leaner or richer than the stoichiometric air-fuel ratio.

When the engine temperature is relatively high (and the vehicle speed is less than a predetermined high speed value), the temperature-sensitive valve 40 makes the third negative pressure passage L3 conductive; 5v
, the solenoid is demagnetized by the opening of the negative pressure chamber 66.
Since the second relief passage LL2 connected to the air passage LL2 and the common relief passage LIC connected to the atmosphere opening port 13 are communicated with each other, the negative pressure entering the third negative pressure passage L3 from the intake manifold 11 passes through the orifice J4 and then passes through the relief passage L12. ．． It is discharged to the atmosphere opening 13 via the LLC. Therefore, the negative pressure chamber 6
Since no negative pressure is still applied to the fuel increase valve 61, the fuel increase valve 61 is kept open, and a mixture having a substantially stoichiometric air-fuel ratio is obtained.

As a result, the engine E can exhibit good acceleration performance in the low vehicle speed range.

When the engine temperature is relatively high and the vehicle speed is higher than a predetermined high speed value, the conduction state of the third negative pressure passage L3 remains unchanged and the first
When the second vehicle speed detection switch Sυ2 is opened, the solenoid valve Vs is energized by the second circuit 71 to energize the solenoid and close the second relief passage L12, so that the orifice J4
The negative pressure inside the intake manifold Mi that has passed through the negative pressure chamber 66
It acts on

By the way, the negative pressure inside the intake manifold M (well, throttle valve 3)
In other words, in the low load range, high negative pressure acts on the negative pressure chamber 66 and returns the diaphragm 65 to resist the force of 61 J267. to close the valve body 64. As a result, the amount of fuel jetted from the fuel nozzle 4 is reduced as described above,
The air-fuel mixture is returned to the normal lean air-fuel ratio, thereby reducing fuel consumption.

On the contrary, in a high load range, the negative pressure in the negative pressure chamber 66 decreases, so the valve body 64 is opened and the amount of fuel jetted from the fuel nozzle 4 is increased, so that the engine E has a substantially stoichiometric air-fuel ratio. It can produce high output when supplied with Qi.

Further, when the vehicle speed is within a predetermined low speed value or high speed value range and the engine E is in a predetermined low load state, the first vehicle speed detection switch Sv is closed and the load detection switch St
Since the negative pressure chamber 75 receives the high negative pressure in the intake manifold M i and is closed, the first solenoid valve VS1 is closed by the first circuit 70.
The solenoid is energized and the second relief passage L is energized.
Close t2. Therefore, all the high negative pressure in the intake manifold hr that has passed through the orifice J4 is introduced into the negative pressure chamber 66, so the fuel increase valve 61 is closed and the air-fuel mixture is returned to the normal lean air-fuel ratio. This will reduce fuel consumption.

<Exhaust recirculation control> When the engine temperature is relatively low, the downstream side of the first negative pressure passage L1 connected to the negative pressure chamber 9 of the temperature sensing valve 11 car recirculation amount control valve 6 is communicated with the atmosphere opening 13. Atmospheric pressure acts on the negative pressure chamber 9, and the recirculation amount control valve 6 (or 11) is activated to stop the recirculation of exhaust gas.

When the engine temperature is relatively high, the temperature-sensitive valve 11h and the atmosphere opening port 13 are closed to bring the first negative pressure passage L1 into a conductive state. At this time, if the vehicle speed is less than a predetermined high speed value, the second vehicle speed detection switch Sυ2 is opened, and the first solenoid valve VS1 blocks the first relief passage LL. Therefore, when the negative pressure generated near the throttle valve 3 due to the operation of the engine E is detected in the first negative pressure detection hole D1, the negative pressure 1)C is the temperature-sensitive valve 11.
, is transmitted to the negative pressure chamber 32 of the air valve V2 via the orifice 12 and the communication path 36, 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 Lc is Make conductive. When the control air intake path LC becomes conductive, outside air is sucked into the atmosphere opening port 13, and -
After the flow rate is regulated by orifices J1 and J2 before and after the negative pressure chamber 22 of the air regulating valve V1, it is sucked into the intake path of the engine E via the valve chamber 30 and valve port 35 of the air valve V2. Along with this, adjustment valve V.

Negative pressure P12 is applied to the negative pressure chamber 22 of the air valve V2 and the valve chamber 30 of the air valve V2.
and P2 are generated, and their negative pressure ratio is determined by the throttle ratio of the orifices Jl and 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 Pυ and the detected negative pressure Pυ of the second negative pressure detection hole D2 overcomes the set load of the valve spring 240, the valve body 23 is pulled up via the diaphragm 21 and the valve port 25 is opened. Therefore, a part of the negative pressure pv passes through the valve port 25 and dilutes the negative pressure that previously passed through the orifice 12 to form a negative pressure pe, which is used as the operating negative pressure of the reflux control valve 6. It acts on the pressure chamber 9.

According to the above-mentioned dilution of the negative pressure, a decrease in the operating negative pressure 1)e 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 decreases.

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 operating negative pressure pe rises, which is fed back to the air valve V2, causing the valve body 23 to open the valve port 25 by an action opposite to the above, and the same action is repeated thereafter, and this repetition is performed very quickly. , so the negative pressure P
A constant pressure ratio can be given to υ and pe, which is equal to the pressure ratio of negative pressures P1 and P2.

Therefore, if the intake air amount of the engine E is small, the negative pressure PI is higher than the negative pressure Pυ, so the valve body 23 of the regulating valve V1 is located on the opening side, and the operating negative pressure 1) g of the reflux control valve 6 is On the other hand, if the intake air amount is large (on the contrary, the negative pressure Pυ rises, the valve body 23 moves to the closing side, and the operating negative pressure pC rises. Thus, the air valve 2 becomes the negative pressure pe). The open state time and closed state time are controlled accordingly, and the opening area of the recirculation amount control valve 6 is controlled by the same negative pressure pe, so the amount of air flowing through the control intake path Lc and the amount of exhaust gas recirculation are In fact, the intake air amount and exhaust recirculation amount of engine E are proportional, and engine E
The exhaust gas can be sucked in at a constant reflux rate. In other words, the amount of J-11 air recirculated is increased in accordance with the increase in the load on the engine E. The above exhaust gas recirculation rate is l) v and p
It is predetermined by the pressure ratio of e and thus the restriction ratio of the orifices J, , J2.

Next, during high-speed operation when the vehicle speed exceeds a predetermined high-speed value, the second vehicle speed detection switch SU2 is closed and the first solenoid valve I'
Sl is energized by the second circuit 71 to excite the solenoid, thereby communicating the first relief passage Ll and the common relief passage Llc. As a result, since the downstream side of the second negative pressure passage L2 communicates with the atmosphere opening port 13, the valve chamber 20 of the regulating valve V1 is maintained at atmospheric pressure, and the valve body 23 is positioned on the open side, so that the operating negative pressure 1 ) As c decreases, the opening degree of the recirculation amount control valve 6 decreases, and the exhaust gas recirculation rate decreases as a result of the decrease, contributing to an increase in the output of the engine.

In addition, the vehicle speed is within a predetermined low speed value or high speed value range,
In addition, when the engine E is in a predetermined low load state, both the first vehicle speed detection switch SvI and the load detection switch St are closed, so that the first solenoid valve Vs is in the first circuit 70.
energizes the solenoid. Therefore, as in the case of high-speed operation, the exhaust gas recirculation rate is reduced and the combustion of the air-fuel mixture is stabilized.

Negative pressure in the intake manifold +lf i is introduced into the first negative pressure chamber 55□ of the ignition timing control device 52 via the downstream side of the control intake passage Lc and the fourth negative pressure passage L4.

Therefore, the first negative pressure chamber 55. The negative pressure decreases or increases as the load on the engine E increases, so when the load is high, the first diaphragm 541 moves to the right by the elastic force of the spring 58 and operates the operating rod 51 in the retard direction. , the ignition timing of engine E is delayed. In contrast, when the load is low, the first diaphragm 54 overcomes the suction force due to the negative pressure or the force of the spring 58.
．． is moved to the left to operate the operating rod 51 in the advance direction to advance the ignition timing. When the first diaphragm 541 contacts the stopper pin 57 and is prevented from moving to the left, the ignition timing reaches its advance limit.

By the way, when the engine temperature is relatively low, the temperature-sensitive valve 11
communicates the downstream side of the first negative pressure passage L1 with the atmosphere opening port 13, so atmospheric pressure flows from the atmosphere opening port 13 through the first negative pressure passage 8, the seventh negative pressure passage L7, and the fifth negative pressure passage L5. Then, it acts on the second negative pressure chamber 552 of the ignition timing control device 52. Therefore, the second diaphragm 54□ moves to the right by the force of the spring 59 to a position where it contacts the stopper wall 56, thereby holding the stopper pin 57 in the forward position. Therefore, the ignition advance limit in this case remains at the first limit.

When the engine temperature is relatively high, the temperature-sensitive valve 11 brings the first negative pressure passage into a conductive state, so that the negative pressure detected by the first negative pressure detection hole in the intake passage 1 becomes the first negative pressure passage. The second negative pressure chamber 55 passes through the negative pressure passage "I, the seventh negative pressure passage L7, and the fifth negative pressure passage L5.
．． will be introduced in The negative pressure detected by the first negative pressure detection hole D1 is low at the idle opening position of the throttle valve 3, high in the low opening range exceeding the idle opening, and becomes low again when entering the high opening range. Therefore, when the engine is idle or under high load, the negative pressure in the second negative pressure chamber 55□ is low, so the second diaphragm 542 moves to the right in the same way as when the temperature is low to maintain the stopper pin 57 in the forward position. The ignition advance limit is kept at the first limit, but when the load is low, the negative pressure in the z2 negative pressure chamber 552 is increased, and in response to the negative pressure, the second diaphragm 5
42 moves to the left to retreat the stopper pin 57 and advance the ignition advance limit from the first limit to the second limit.

When the vehicle speed is within a predetermined low speed (a range of direct °C and high speed values) and the engine E is in a predetermined low load state, both the first vehicle speed detection switch Sv1 and the load detection switch SL are closed. Therefore, the second solenoid valve V, 92 is energized by the first circuit 70 to excite the solenoid, and communicates between the fifth and sixth negative pressure passages. High negative pressure is introduced into the second negative pressure chamber 55□ via the control intake passage Lc, the sixth negative pressure passage, and the fifth negative pressure passage L5, and this also causes the second diaphragm 542 to move to the left and close the stopper pin. 57, the ignition advance limit is advanced to the second limit.

The following table is created to make it easier to understand the interlocking relationship of the three RDLs mentioned above.

In this way, when the engine is at a low temperature, good combustion can be achieved by enriching the air-fuel mixture and stopping exhaust recirculation, and by suppressing the ignition advance limit to the limit of 1, it is possible to prevent the occurrence of partial knocking. This not only facilitates warm-up, but also enables smooth warm-up running. In addition, at high temperatures and low loads, the air-fuel ratio of the air-fuel mixture is diluted and a small amount of exhaust gas is recirculated, reducing fuel consumption and suppressing the generation of NOx in exhaust gas.Moreover, by advancing the ignition advance limit to the second limit, Since it compensates for the slow combustion speed of a lean mixture, it is possible to maximize the power output. Furthermore, at high temperatures and high loads, the air-fuel ratio of the air-fuel mixture is enriched and a large amount of exhaust gas recirculates to achieve high output and suppress the generation of NOx in the exhaust gas, and to suppress the ignition advance limit to the first limit. This can prevent knocking from occurring. Furthermore, during deceleration, it is possible to reduce fuel consumption and stabilize combustion by diluting the air-fuel ratio of the air-fuel mixture, reducing or stopping exhaust gas recirculation, and regulating the ignition advance to the first limit.

As described above, according to the present invention, when the engine is at low temperature or under high load, the air-fuel ratio of the air-fuel mixture is enriched to approximately the stoichiometric air-fuel ratio, and the ignition advance limit is kept at the first limit. It stabilizes the air-fuel mixture, increases output, and prevents knocking, which promotes warm-up, improves acceleration and drivability, and also dilutes the air-fuel ratio of the mixture and improves ignition speed at low loads. Since the angular limit is advanced to the second limit, it is possible to reduce fuel consumption while maximizing output, without impairing drivability.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic diagram showing one embodiment of the device of the present invention, and FIG.
The figure is the first in it. It is a control electric circuit diagram of a 2nd electromagnetic valve. C... Carburetor, E... Internal combustion engine, Mi... Intake manifold, Sυl+Sv2... 1st. 2nd vehicle speed detection switch, Vs, , Vs2-1st. 2nd solenoid valve, 5l
=-Load detection switch, 3. Throttle valve, 5. Exhaust recirculation path, 6. Reflux flow control valve, 11. Temperature sensing valve, 40. Temperature sensing valve, 50. Power distributor, 52. ...Ignition timing side 1 device, 602...Second fuel jet (one element of the fuel increase device), 61...Fuel increase valve (one element of the fuel increase device) Patent applicant Honda Motor Co., Ltd.

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 air-fuel ratio of the air-fuel mixture is adjusted to approximately the stoichiometry depending on the low temperature state or high load state of the engine. A fuel increasing device that operates to increase the amount of fuel supplied to the intake system in order to enrich the air-fuel ratio, and regulating the advance limit of ignition timing to a first limit when the fuel increasing device is activated and g1 when it is not activated. 1. A control device for an internal combustion engine, comprising: an ignition timing control device interlocking with a nuclear fuel increase device so as to regulate the fuel to a second limit that is more advanced than the limit. (2. In the item described in claim (1),
The fuel increasing device is a control device for an internal combustion engine that is also linked to an exhaust gas recirculation control device so that the amount of exhaust gas recirculation is increased when the fuel increasing device is activated and decreased when the fuel increasing device is not activated. (3) A control device for an internal combustion engine according to claim (1) or (2), wherein the fuel increase device is inoperative at low vehicle speeds and low load conditions.