JP3968902B2 - Ignition timing control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ignition timing control device that controls the ignition timing of an internal combustion engine.
[0002]
[Prior art]
In an internal combustion engine, it is common to perform ignition timing control for controlling the ignition timing for the air-fuel mixture in each cylinder. The ignition timing correction in the ignition timing control includes catalyst warm-up delay angle correction, idle stabilization correction, and others. The catalyst warm-up delay correction is for increasing the temperature of the exhaust gas by retarding the ignition timing and raising the temperature of the exhaust purification catalyst to the activation temperature or the like earlier.
[0003]
The idle stabilization correction is to stabilize the engine speed during idling by adjusting the engine output by advancing or retarding the ignition timing. JP-A-57-83665, JP-A-58-59371, JP-A-62-294771, and JP-A-2 can be used to stabilize the engine idling speed by correcting the ignition timing. -259279 and the like are known.
[0004]
[Problems to be solved by the invention]
There is a case where the above-described idle stabilization correction is further performed in order to stabilize the idle rotation in a state where the above-described catalyst warm-up correction is performed to warm up the catalyst and the retard angle correction is performed with respect to the ignition timing. is there. At this time, if various conditions overlap, there is a case where the correction of the ignition timing is overcompensated by the correction of both and the idling rotation is not stabilized. This will be briefly described below.
As described above, the stabilization of the idle rotation by the ignition timing control is a control for adjusting the output by advancing or retarding the ignition timing within a certain range so that the idle rotation speed matches the target rotation speed. Here, as shown in FIG. 7, when the engine is in a normal operation state, the ignition timing is close to MBT (Minimum spark advance for Best Torque). The fluctuation range of the engine output corresponding to the correction range A of the ignition timing by the stabilization correction is a.
[0006]
However, if the same idling stabilization control is performed on the retard side where the catalyst warm-up retard angle correction is performed, the fluctuation range of the engine output with respect to the correction range A is b. In other words, in the state where the warm-up delay angle correction is being performed, the output fluctuation range b due to the idle stabilization correction becomes large, so that the output may be excessively changed and the idle rotation may not be stabilized.
[0007]
Accordingly, an object of the present invention is to provide an ignition timing control device that can achieve both of the catalyst warm-up delay angle correction and the idle rotation stabilization correction and reliably stabilize the idle rotation.
[0008]
[Means for Solving the Problems]
An ignition timing control device according to the present invention includes a catalyst warm-up retarding means for determining a correction delay amount for raising the temperature of the exhaust purification catalyst by retarding the ignition timing, and matching the idle speed with the target speed. The idle stabilization advance / retarding means for determining the corrected advance / retard amount means for stabilizing the idle speed by advancing or retarding the ignition timing as described above, The corrected advance / retard amount is changed according to the corrected retard amount of the ignition timing by the catalyst warm-up retard means.
[0009]
According to the ignition timing control device of the present invention, since the correction advance / delay amount by the idle stabilization correction is changed according to the catalyst warm-up correction delay amount, the ignition timing is corrected by the catalyst warm-up delay angle correction. Even if is set to the retard angle side, the range of the correction advance / delay angle amount of the idle stabilization correction can be changed, and overcompensation is not caused when the idle rotation is stabilized. As a result, the catalyst warm-up delay angle correction and the idle stabilization advance / delay correction can be achieved at a high level.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
First, a first embodiment of the ignition timing control device of the present invention will be described with reference to the drawings.
[0011]
As shown in FIG. 1, the ignition timing control device of the present embodiment controls the ignition timing of an ignition plug 2 of an engine 1 that is an internal combustion engine. The ignition plug 2 is attached to each cylinder 3 one by one. It has been. The air sucked from the outside passes through the intake passage 4 and is mixed with the fuel injected from the injector 5 and is sucked into the cylinder 3 as an air-fuel mixture. An intake valve 6 opens and closes the inside of the cylinder 3 and the intake passage 4. The air-fuel mixture combusted inside the cylinder 3 is exhausted to the exhaust passage 7 as exhaust gas. An exhaust valve 8 opens and closes the inside of the cylinder 3 and the exhaust passage 7.
[0012]
A throttle valve 9 that adjusts the amount of intake air taken into the cylinder 3 is disposed on the intake passage 4. A throttle position sensor 10 for detecting the opening degree is connected to the throttle valve 9. An air bypass valve 12 that adjusts the amount of intake air supplied to the cylinder 3 via the bypass passage 11 when idling (when the throttle valve 9 is fully closed) is also disposed on the intake passage 4. Further, a vacuum sensor 13 for detecting the intake pipe negative pressure is also mounted on the intake passage 4.
[0013]
A crank position sensor 14 for detecting the position of the crankshaft is attached in the vicinity of the crankshaft of the engine 1. From the output result of the crank position sensor 14, the position of the piston 15 in the cylinder 3 and the rotational speed of the engine 1 can be known. The engine 1 is also provided with a knock sensor 16 that detects knocking of the engine 1 and a water temperature sensor 17 that detects the cooling water temperature.
[0014]
These spark plug 2, injector 5, throttle position sensor 10, air bypass valve 12, vacuum sensor 13, crank position sensor 14, knock sensor 16, water temperature sensor 17 and other sensors are connected to an electronic control unit (ECU) 18. It is connected and controlled based on a signal from the ECU 18 or sends a detection result to the ECU 18. The ECU 18 is also connected to an accelerator position sensor 19 that detects the accelerator opening and a catalyst temperature sensor 21 that measures the temperature of the exhaust purification catalyst 20.
[0015]
More precisely, the ignition plug 2 is connected to an igniter and an ignition coil (not shown), and the igniter and the ignition coil are connected to the ECU 18. Then, the igniter and the ignition coil ignite the spark plug 2 based on the ignition signal from the ECU 18.
[0016]
Based on the detection result of the catalyst temperature sensor 21, the ECU 18 determines whether or not the exhaust purification catalyst 20 has reached an activation temperature that exhibits its purification function. If the catalyst temperature has not reached the activation temperature, the ECU 18 sets the ignition timing. Retard. By retarding the ignition timing, the exhaust gas temperature is raised and the exhaust purification catalyst 20 is heated. That is, the ECU 18 functions as a catalyst warm-up retarding means together with the catalyst temperature sensor 21 and the like.
[0017]
The ECU 18 also functions as an idle stabilization advance / retarding means together with the throttle position sensor 10, the vacuum sensor 13, the crank position sensor 14, the accelerator position sensor 19, and the like. That is, when it is determined from the detection results of the throttle position sensor 10 and the accelerator position sensor 19 that the engine 1 is in an idle state, the ECU 18 calculates the target engine speed from the intake pipe negative pressure detected by the vacuum sensor 13 or the like. (In some cases, an air flow meter, not a vacuum sensor, is provided on the intake passage 4 and calculated from this output).
[0018]
In parallel with this, the ECU 18 also detects the actual engine speed (actual engine speed) by the crank position sensor 14, and sets the ignition timing within a certain range so that the actual engine speed becomes the target engine speed. Use to advance or retard. By advancing or retarding the ignition timing, the engine output is adjusted and the idling rotation is stabilized. When the actual engine speed is lower than the target engine speed, advance is performed, and when the actual engine speed is higher than the target engine speed, retard is performed.
[0019]
The above-described control for stabilizing the idling speed is particularly focused on the ignition timing, but in parallel with this, the control for stabilizing the idling speed by controlling the intake air amount during idling is performed in parallel. Done. What is controlled at this time is the amount of intake air, which adjusts the opening of the air bypass valve 12. In addition, the control for stabilizing the idle rotation by controlling the amount of fuel injected from the injector 5 at the time of idling is also performed in parallel. What is controlled at this time is the fuel injection amount, which adjusts the valve opening time of the injector 5.
[0020]
Next, the control for determining the correction retardation amount K1 for the idle stabilization correction by the above-described ignition timing control device will be described.
[0021]
First, a basic process when the ignition timing of the engine 1 is determined by the ECU 18 or the like will be briefly described.
[0022]
The ignition timing is determined based on the following formula (I).
Ignition timing = initial set ignition timing + basic advance (slow) angle + correction advance (slow) angle ... (I)
Here, the initial set ignition timing is fixed at BTDC 5 ° (piston 15 position is 5 ° before the top dead center) when the engine is started, and ATDC 5 ° (piston 15 position is fixed when the coolant temperature is higher than the set value). It is fixed at 5 ° after top dead center. The initial set ignition timing is corrected by a basic advance (slow) angle in consideration of the load state of the engine 1 or a correction advance (slow) angle for various corrections, and a final ignition timing is determined.
[0023]
The basic advance angle is determined from the map according to the engine load at that time based on the detection result of the vacuum sensor 13 (air flow meter) or the like. On the other hand, the correction advance angle is a combination of various corrections. Among these various corrections, in addition to the catalyst warm-up correction and idle stabilization correction described above, the warm-up advance correction and transient There are retardation correction, retardation correction at the time of fuel cut return, acceleration retardation retardation, knocking suppression correction, and the like.
[0024]
The warm-up advance correction is a correction for stably performing the warm-up operation of the engine at the cold start. When the engine 1 is in a cold state, it is difficult to ignite the air-fuel mixture or the flame propagation in the cylinder 3 tends to be slow, and the rotation of the engine 1 is not stable. Therefore, the ignition timing is advanced so that ignition to the air-fuel mixture and flame propagation are not delayed, and the warm-up operation for warming up the engine 1 is stably performed.
[0025]
The transient retardation correction is to prevent knocking by retarding the ignition timing at the time of rapid acceleration when the coolant temperature is a predetermined value or more. The delay correction at the time of returning from the fuel cut is to reduce the shock by delaying the ignition timing at the time of returning from the fuel cut. The acceleration retardation correction is intended to improve drivability by temporarily retarding the ignition timing during acceleration.
[0026]
In the knocking suppression correction, when knocking occurs, the ignition timing is retarded until knocking does not occur, and when knocking does not occur, the ignition timing is advanced until just before knocking occurs. The reason why the ignition timing is advanced to immediately before the occurrence of knocking when knocking has not occurred is that there is the ignition timing MBT at which the output torque is maximized immediately before the knocking region where knocking occurs.
[0027]
As described above, the final ignition timing is determined based on the formula (I), but for the sake of simplicity, only the catalyst warm-up delay correction and the idle stabilization advance / delay correction are described below. Focusing on the above, the ignition timing control by the ignition timing control device of the present embodiment will be described below. In the following description, the correction advance angle of the last term of the formula (I) will be described only about the catalyst warm-up delay angle correction and the idle stabilization advance delay angle correction, but the other corrections described above are simultaneously performed. Needless to say, it is applicable.
[0028]
The temperature of the exhaust purification catalyst 20 detected by the catalyst temperature sensor 21 is taken into the ECU 18 at regular intervals, and the ECU 18 detects the rise of the exhaust purification catalyst 20 from the detection result of the catalyst temperature sensor 21 and other vehicle state quantities. Determine if temperature is needed. When the ECU 18 determines that the temperature of the exhaust purification catalyst 20 needs to be increased, the catalyst warm-up delay for the catalyst warm-up correction described above is performed based on the difference between the current temperature of the exhaust purification catalyst 20 and the target temperature. Determine the angular amount. These determinations and determinations are repeated at regular intervals by a program stored in the ROM in the ECU 18.
[0029]
On the other hand, following the determination of the catalyst warm-up delay amount described above, if the ignition timing correction amount for idle stabilization correction (hereinafter also referred to as the correction delay amount K1, the correction delay amount K1 takes a negative value) The actual correction is an advance angle). A program for determining the correction retardation amount K1 is also stored in the ROM in the ECU 18, and is repeatedly performed at regular intervals while the engine 1 is idling. A flowchart for determining the corrected retardation amount K1 is shown in FIG.
[0030]
First, the determined catalyst warm-up retardation amount is read (step 100). The lower the temperature of the exhaust purification catalyst 20 detected by the catalyst temperature sensor 21, the greater the catalyst warm-up retardation amount. Next, a difference Δne between the target engine speed calculated based on the detection result of the vacuum sensor 13 and the like and the actual engine speed calculated from the detection result of the crank position sensor 14 is calculated (step 110).
[0031]
Based on the read catalyst warm-up delay amount and the calculated Δne, the map shown in FIG. 3 stored in the ROM of the ECU 18 is searched to obtain the corrected delay amount K1 (step 120), and the idling is stabilized. A correction retardation amount K1 is set as a correction ignition timing correction amount (step 130). The ECU 18 calculates the final ignition timing based on the equation (I) based on the set correction retardation amount K1, and sends an ignition signal to the igniter.
[0032]
As shown in FIG. 3, for example, when the catalyst warm-up delay amount is 5 ° CA and the actual engine speed is 50 rpm higher than the target speed (Δne = -50), the idling stabilization correction is performed. The corrected retardation amount K1 is 4.0 ° CA. That is, at this time, 4.0 ° CA retard correction is performed for idle stabilization correction, and the catalyst warm-up delay amount of catalyst warm-up delay correction is 5 ° CA. A total of 9.0 ° CA delay correction is performed with catalyst warm-up delay correction. The catalyst warm-up delay amount of 0 ° CA means that the catalyst warm-up delay angle correction is not performed.
[0033]
Further, as can be seen from FIG. 3, as the catalyst warm-up delay amount increases, the control range of the correction delay amount K1 of the idle stabilization correction decreases. By doing so, as shown in FIG. 4, when the catalyst warm-up delay angle correction is performed, the fluctuation range a ′ of the output of the engine 1 due to the idle stabilization correction is equal to when the catalyst warm-up delay angle correction is not performed. Is substantially equal to the fluctuation range a.
[0034]
As a result, regardless of the value of the catalyst warm-up delay amount, the fluctuation range of the output of the engine 1 by the idling stabilization correction becomes almost equal, and the catalyst warm-up delay correction and the idling stabilization correction As a result, the correction of the ignition timing is not overcompensated. As a result, the idling speed can be stabilized while raising the temperature of the exhaust purification catalyst 20 by the catalyst warm-up correction.
[0035]
Next, a second embodiment of the ignition timing control device of the present invention will be described.
[0036]
Since the configuration of the ignition timing control device of the present invention is the same as that of the first embodiment described above, description thereof is omitted.
[0037]
As described above, the ignition timing is determined by equation (I), but the correction advance angle in the last term of equation (I) includes corrections other than catalyst warm-up delay correction and idle stabilization correction. That is, warm-up advance angle correction for stabilizing the warm-up operation of the engine 1 can also be performed at the time of idling immediately after the cold start (other corrections described above are performed at the time of idling immediately after the cold start. Not implemented). In the first embodiment, the ignition timing of the idle stabilization correction is set so that the fluctuation range of the output of the engine 1 by the idle stabilization correction becomes substantially the same regardless of the value of the catalyst warm-up retardation amount. The control range was variably controlled.
[0038]
However, if the ignition timing is advanced by the warm-up advance correction described above, even if the control range of the ignition timing by the idle stabilization correction is variably controlled, the engine 1 by the idle stabilization correction by the warm-up advance correction. The output fluctuation range becomes large. Therefore, in the present embodiment, when the warm-up advance correction is performed, the correction delay amount K of the idle stabilization correction has a component that cancels the warm-up advance correction.
[0039]
In the present embodiment, the correction value of the ignition timing by the idle stabilization correction is obtained as corrected retard amount K = corrected retard amount K1 + corrected retard amount K2. The corrected retard amount K1 is the same as the corrected retard amount K1 in the first embodiment described above, and the corrected retard amount K2 is a component for canceling the warm-up advance correction. Since the advance amount of the warm-up advance angle correction amount is determined based on the coolant temperature of the engine 1, the corrected retard amount K2 is determined based on the coolant temperature of the engine 1 so as to offset this. . A flow chart for determining the correction retardation amount K is shown in FIG.
[0040]
Based on FIG. 5, the control for determining the correction retardation amount K of the idle stabilization correction by the ignition timing control device of the present embodiment will be described, but the first half is the same as the control of the first embodiment described above. Therefore, the same step number is hidden and the detailed description is omitted.
[0041]
After step 120 of the first embodiment is performed and the corrected retardation amount K1 is determined, the cooling water temperature detected by the water temperature sensor 17 is read by the ECU 18 (step 140). In the ECU 18, the map shown in FIG. 6 stored in the ROM is searched, and the corrected retardation amount K2 is determined according to the detected coolant temperature (step 150). The correction delay amount K2 is larger as the water temperature is lower, that is, the correction amount greatly advanced by the warm-up advance correction is canceled out. If the coolant temperature is sufficiently warm (50 ° C. or higher), the warm-up advance angle correction is not performed, so the correction delay amount K2 is naturally 0 (zero).
[0042]
Next, a corrected retardation amount K is calculated from K = K1 + K2 (step 160), and the corrected retardation amount K is set as an ignition timing correction amount for idle stabilization correction (step 170). The ECU 18 calculates the final ignition timing based on the set correction retardation amount K based on the formula (I), and sends an ignition signal to the igniter.
[0043]
In this way, the correction amount of the ignition timing by the idle stabilization correction is not variably controlled only according to the correction delay amount of the catalyst warm-up correction, and the correction delay amount of the catalyst warm-up correction and other control amounts It is also possible to variably control based on both. In the case of the present embodiment, even when the warm-up advance angle correction is performed to stabilize the warm-up operation of the engine 1, the range of the engine output that fluctuates due to the idle stabilization correction becomes substantially equal, and the catalyst The ignition timing correction is not overcompensated by the warm-up delay angle correction and the idle stabilization correction. As a result, the idling speed can be stabilized while raising the temperature of the exhaust purification catalyst 20 by the catalyst warm-up correction.
[0044]
The ignition timing control device of the present invention is not limited to the above-described embodiment. For example, in the above-described embodiment, as shown in FIG. 3, the catalyst warm-up delay amount is set to four stages and Δne is set to five stages. However, these stages may be increased, and not the map. The corrected retardation amount K1 may be obtained by an arithmetic expression.
[0045]
Further, in the above-described embodiment, the temperature of the exhaust purification catalyst 20 is low and the exhaust purification catalyst 20 is heated to the activation temperature earlier. It can also be used when the exhaust purification catalyst 20 is heated for a reason. For example, when the exhaust purification catalyst 20 is poisoned by nitrogen oxide NOx or sulfur oxide SOx, the temperature of the exhaust purification catalyst 20 is raised when recovering from such poisoning.
[0046]
【The invention's effect】
In the ignition timing control device of the present invention, the correction advance / delay amount by the idle stabilization correction is changed in accordance with the catalyst warm-up correction delay amount. Even if the retard angle is set, the range of the correction advance / deceleration amount of the idle stabilization correction can be changed, and overcompensation is not required when the idle rotation is stabilized. As a result, the catalyst warm-up delay angle correction and the idle stabilization advance / delay correction can be achieved at a high level.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a configuration of an ignition timing control device of the present invention.
FIG. 2 is a flowchart of control for determining a correction retardation amount K1 for idle stabilization by the apparatus of the first embodiment.
FIG. 3 is a map of a correction retardation amount K1 in the apparatus of the first embodiment.
FIG. 4 is a graph showing the relationship between ignition timing and engine output in the apparatus of the first embodiment.
FIG. 5 is a flowchart of control for determining a correction retardation amount K for idle stabilization by the apparatus of the second embodiment.
6 is a map of cooling water temperature-corrected retardation amount K2 in the apparatus of the second embodiment. FIG.
FIG. 7 is a graph showing the relationship between ignition timing and engine output in a conventional apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Spark plug, 3 ... Cylinder, 4 ... Intake passage, 5 ... Injector, 6 ... Intake valve, 7 ... Exhaust passage, 8 ... Exhaust valve, 9 ... Throttle valve, 10 ... Throttle position sensor, 13 ... Vacuum sensor, 14 ... crank position sensor, 15 ... piston, 16 ... knock sensor, 17 ... water temperature sensor, 18 ... ECU, 19 ... accelerator position sensor, 20 ... exhaust purification catalyst, 21 ... catalyst temperature sensor.

Claims (4)

Catalyst warm-up retarding means for determining a correction delay amount for retarding the ignition timing and raising the temperature of the exhaust purification catalyst;
Idle stabilization advance / retarding means for determining a correction advance / deceleration amount for stabilizing the idle speed by advancing or retarding the ignition timing so that the idle speed matches the target speed. And
The idle stabilization advance / retarding means changes the corrected advance / retard amount according to the corrected retard amount of the ignition timing by the catalyst warm-up retard means ,
The ignition timing control device according to claim 1, wherein the larger the correction delay amount by the catalyst warm-up delay means, the narrower the correction range of the correction advance / delay amount by the idle stabilization advance / retard means . Catalyst warm-up retarding means for determining a correction delay amount for retarding the ignition timing and raising the temperature of the exhaust purification catalyst;
Idle stabilization advance / retarding means for determining a correction advance / deceleration amount for stabilizing the idle speed by advancing or retarding the ignition timing so that the idle speed matches the target speed. And
The idle stabilization advance / retarding means is based on the correction retard amount determined by the catalyst warm-up retarding means and a deviation between the target engine speed and the actual engine speed, and Determine the quantity ,
The ignition timing control device according to claim 1, wherein the larger the correction delay amount by the catalyst warm-up delay means, the narrower the correction range of the correction advance / delay amount by the idle stabilization advance / retard means . Engine warm-up advance advance means for determining an engine warm-up correction advance amount for stabilizing engine warm-up operation during idling immediately after cold start;
Cooling water temperature detecting means for detecting the cooling water temperature of the engine;
Canceling retarding means for determining a canceling correction retarding amount for retarding the ignition timing and canceling the engine warm-up correction advancement amount;
3. The ignition timing control device according to claim 1, wherein the cancellation delay angle unit changes the cancellation correction retardation amount in accordance with a coolant temperature detected by the cooling water temperature detection unit. 4. The ignition timing control device according to claim 3 , wherein the cancellation delay angle determining unit determines the cancellation correction retardation amount larger as the cooling water temperature detected by the cooling water temperature detection unit is lower.

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