JP3003468B2 - Ignition timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition timing control device for suppressing knocking of an internal combustion engine.

[0002]

2. Description of the Related Art It is known to retard ignition timing to suppress knocking. In general, such ignition timing retard control is performed when the occurrence of knocking is detected in order to prevent the ignition timing from being unnecessarily retarded and fuel consumption and exhaust emission from deteriorating. The ignition timing is gradually retarded from the basic ignition timing for each state. Further, in order to accelerate the suppression of knocking, after retarding by a predetermined retard amount not exceeding the required retard amount based on the retard amount set for each predetermined load region, the retard amount of the ignition timing is gradually increased or decreased. It has also been proposed to control.

The above-mentioned predetermined retard amount can be estimated to a certain extent for each predetermined rotational speed range when the engine is under a high load, so that the occurrence of knocking can be estimated to a certain extent. In order to further improve the responsiveness, it is preferable to set the actual retard amount as close as possible to each actual retard amount.
Japanese Patent Application Laid-Open No. 5575 discloses a system in which learning control is performed for each of the aforementioned predetermined retardation amounts during operation of the engine. In this learning control, in each of the above-described operation regions, the predetermined retard amount is replaced with the value each time the retard amount at the completion of the retard exceeds the current predetermined retard amount.

[0004]

The occurrence of knocking is worse in a transient state than in a steady state, and is particularly worse in a transient state such as sudden acceleration / deceleration of an engine. In the prior art described above, if the vehicle enters the learning operation region in such a transient state, the amount of retard learned at this time becomes large, and the driver very frequently operates in the learning operation region in such a transient operation region. In this case, good learning control is performed, but if not, a retard that is significantly greater than the required retard amount will be executed from the next time, resulting in deterioration of fuel consumption and exhaust emission.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide an ignition timing control device which can learn a retard amount suitable for a driver's driving manner and realizes a good ignition timing retard when knocking occurs. It is to be.

[0006]

SUMMARY OF THE INVENTION An ignition timing retarding device according to the present invention is designed so that, when knocking occurs, the knocking is retarded from a basic ignition timing by a necessary retarding amount which suppresses knocking to a predetermined level or less. An ignition timing retarding means for delaying by a second retardation amount which is further increased and decreased in a feedback manner after a skipped retardation by one retardation amount, and which is increased or decreased in accordance with the increase or decrease of the second retardation amount; A calculating means for calculating a smoothed value of the second retardation amount which increases more gently at least when the amount of the second retardation is increased, and a smoothed value of the second retardation amount calculated by the calculating means falls within a predetermined range. First retard amount updating means for updating the first retard amount on the increasing side when the value exceeds the predetermined range, and updating the first retard amount on the decreasing side when the value exceeds the predetermined range. It is characterized by.

[0007]

The ignition timing control device is arranged so that the ignition timing retarding means retards the basic ignition timing from the basic ignition timing by a necessary retardation amount at which knocking is suppressed to a predetermined level or less when knocking occurs. After skipping the retardation by the retardation amount, the retardation is performed by the second retardation amount which is further increased and decreased in a feedback manner, and the calculating means increases or decreases in accordance with the increase or decrease of the second retardation amount. A second retardation amount smoothing value that increases more gently when the angle amount increases is calculated, and the first retardation amount updating means determines that the second retardation amount smoothing value calculated by the calculation means falls within a predetermined range. The first retard amount is updated on the increasing side when the value exceeds the predetermined range, and on the decreasing side when the value exceeds the predetermined range.

[0008]

FIG. 1 is a schematic sectional view of an internal combustion engine equipped with an ignition timing control device according to the present invention. In the figure, 1 is an internal combustion engine main body, 2 is a piston, and 3 is a spark plug. A knocking sensor 9 for detecting knocking is attached to the internal combustion engine body 1. An oxygen sensor 5 for detecting the concentration of residual oxygen in the exhaust gas is attached to the exhaust passage 4. In the intake passage 7, a fuel injection valve 6 is installed immediately upstream of the internal combustion engine main body 1, and a throttle valve 10 is arranged upstream of the surge tank 14. The throttle valve 10 has a built-in idle switch and its opening degree. Is connected.
An intake air temperature sensor 8 for detecting an intake air temperature is attached upstream of the throttle valve 10 in the intake passage 7, and an air flow meter 15 for detecting an intake air amount is arranged upstream thereof.

Reference numeral 16 denotes an igniter for outputting a high voltage required for ignition. Reference numeral 17 denotes a distributor which works with a crankshaft (not shown) to distribute and supply the high voltage generated by the igniter 16 to the ignition plug 3 of each cylinder. , 18 are mounted in the distributor 17, and a rotation angle sensor serving also as a rotation speed sensor that outputs 24 pulse signals for one rotation thereof, that is, two rotations of the crankshaft,
Reference numeral 19 denotes a cylinder discrimination sensor that outputs one pulse signal per one rotation of the distributor 17. Reference numeral 24 denotes a transmission of the vehicle, to which a vehicle speed sensor 26 for detecting the vehicle speed from the rotation speed of the output shaft is attached.

Reference numeral 20 denotes an electronic control unit, which is supplied with electric power from a battery 22 via a key switch 21. The electronic control unit 20 includes a CPU 30, a ROM
31, RAM 32, input port 36, and output port 3
8 are interconnected by a common bus 39. The signals of the above-described sensors are input to the input port 36, and general air-fuel ratio control and ignition timing control according to the present invention are executed via the fuel injection valve 6 and the igniter 16 connected to the output port 38.

This ignition timing control is performed according to a first flowchart shown in FIG. This flowchart is
This is executed based on the outputs of the cylinder discrimination sensor 19 and the rotation angle sensor 18, and determines the ignition timing θ in each cylinder. First, at step 101, the current intake air amount Q is measured by the air flow meter 15 and the rotation angle sensor 18.
And the engine speed N are detected and input. Next, at step 102, Q / N is calculated as the engine load,
Proceed to step 103.

In step 103, based on the engine speed N and the engine load Q / N, the basic ignition timing θB in the current engine operating state is determined from a first map as shown in FIG. FIG. 4 is a map at a specific engine speed.
Such a map is stored in the ROM 31 for each engine speed. Next at step 104, similarly the maximum retardation amount theta _max is a maximum retard range for the current engine operating condition is determined from the second map shown in FIG. This map is also a map at a specific engine speed, and such a map is stored in the ROM 31 for each engine speed.

Next, at step 105, it is determined whether or not the determined maximum retardation amount θ _max is 0. When this determination is affirmative, that is, when the engine load Q / N is small as shown in the second map, since knocking hardly occurs, the process proceeds to step 106, and the ignition timing θ is set to the basic ignition timing at this time. θB and ends. This flowchart divides the entire engine operating region into five parts as shown in the map shown in FIG. 6 and executes different ignition timing control for each operating region. This corresponds to the operation state in one area.

On the other hand, if the determination in step 105 is negative, the routine proceeds to step 107, where the knocking sensor 9
Is calculated based on the output. In this processing, the retard amount θK is reset to 0 when the current engine operation state enters a different operation region, and is maintained at 0 if knocking does not occur, and is within the same operation region. At this time, if the knocking still does not become lower than the predetermined level even if the retardation based on the retardation amount θK is executed in the processing described later, each time the processing is repeated, the knocking is increased according to the degree of knocking as shown in FIG. It has become so. Next, the routine proceeds to step 108, where it is determined whether or not the retard amount θK is zero. If this determination is affirmative, there is no need for retarding because knocking has not occurred from the beginning, and the routine proceeds to step 106, where the ignition timing θ is set to the basic ignition timing θB at this time and the process ends. On the other hand, when the determination in step 108 is denied, that is, when knocking initially occurs, step 10
The program proceeds to 9 where it is determined whether or not the current engine operating state is within any of the learning areas A, B and C in FIG.
When this judgment is denied, it is within the second area of FIG.
Proceeding to step 110, the ignition timing θ is determined to be a value delayed from the basic ignition timing θB at this time by the retard amount θK calculated in step 107. In determining the ignition timing theta, guard processing is performed so as not to be retarded beyond the maximum retardation amount theta _max determined at step 104.

On the other hand, if the determination in step 109 is affirmative, the current engine operating state is within one of the three learning areas A, B, and C shown in FIG. Since a load is applied, a relatively large retardation is required to suppress knocking. If the ignition timing is gradually retarded from the basic ignition timing θB as in step 110, the knocking will continue for a long time. become. Therefore,
At this time, the processing after step 111 is executed.

In step 111, it is determined based on the output of the knocking sensor 9 whether knocking is currently occurring. When this judgment is denied, that is,
When the knocking that has occurred initially falls below a predetermined level due to the retardation in the previous processing, the process proceeds to step 113 as it is.

On the other hand, when knocking has occurred, the routine proceeds to step 112, in which the smoothing value is reset to 0 when the current engine operation state enters a different operation region as in the case of the aforementioned retard value θK. θS is increased by a. The smoothing value θS is a value that increases as knocking continues and the retard value θK increases in the same operation region as shown in FIG. 7, but the degree of the increase is set to be gentler than θK. I have. Next, the ignition timing θ is determined by the equation shown in step 113. When determining the ignition timing θ, the maximum retardation amount θ determined in step 104
Guard processing is executed so as not to be retarded beyond _max .

As shown in FIG. 8, the expression shown in step 113 is the maximum retardation amount θ _max ′ at this time from the basic ignition timing θB ′ of the current engine load Q / N ′ and the learning value θGn in this region. , And further retarded by the retard amount θK calculated in step 107. The current ignition timing θ ′ determined in this way can realize a large required retard amount relatively early. Here, the learning value θGn is initially set to an appropriate value for each of the learning regions A, B, and C. However, in order to further improve the responsiveness of the ignition timing retarding at the time of knocking, it is necessary for the driver It is necessary to learn a value suitable for the driving method of the vehicle. This learning is performed according to the second flowchart shown in FIG.

This flowchart is executed when the engine operating state enters one of the learning areas A, B, and C. First, in step 201, the current retard amount θK calculated in the first flowchart is reduced by a predetermined amount b. Next, the routine proceeds to step 202, where the smoothing value θS calculated in the first flowchart is the retardation amount θ
It is determined whether it is greater than K. If this determination is denied, the process proceeds directly to step 204, but if affirmed, the smoothing value θS is set to the retard amount θK and the process proceeds to step 204. In step 204, it is determined whether or not the smoothing value θS is equal to or greater than a first predetermined value α. When the determination is affirmative, the process proceeds to step 205, where the learning value θGn in this learning region is reduced by a predetermined amount C. . This is Figure 8
As described above, the ignition timing θ is set to the retard side.

On the other hand, if the determination in step 204 is negative, the process proceeds to step 206, where the smoothed value θS is set to the second value.
It is determined whether it is equal to or less than the predetermined value β. When the determination is affirmative, the process proceeds to step 207, where the learning value θGn is increased by the predetermined amount d. This means that the ignition timing θ is advanced. When the determination in step 206 is negative, that is, when the smoothed value θS is in the range from β to α, the process proceeds to step 208 without updating the learning value θGn. In step 208, it is determined whether the current engine operation state is within the same learning region,
When this determination is denied, the update of the learning value θGn in the current learning area is terminated, and when affirmative, step 2
09, for example, after waiting for about 500 msec,
The processing after step 201 is repeated.

According to such ignition timing control, when knocking occurs when the current engine operation state is in the second region, the engine is under a medium load, and a large retardation is not required. In order to prevent the ignition timing from being retarded, the ignition timing is gradually retarded using the retardation amount θK that increases in a feedback manner from the basic ignition timing at this time to the required retardation amount.
On the other hand, if knocking occurs when the current engine operation state is in the learning region, the load is under high load and a large retardation is required, so the maximum retardation amount from the basic ignition timing at this time to the required retardation amount θmax and learning value θ in the current learning area
After the difference from Gn is used as the first retard amount, the retard is skipped, and then the retard is gradually retarded by using the retard amount θK as the second retard amount. Thereby, the required retard amount at this time is realized in a short time.

Further, the learning value θGn for each learning region increases more gently with the retardation amount θK that increases in a feedback manner, and decreases in the same manner as the retardation amount θK. Since the value θS is updated on the basis of the value θS, even if the driving in which the knocking occurrence situation is considerably poor is performed in each learning area, the learning value is not immediately updated based on this driving, and the driving value is not updated. Only when the driving is performed very frequently, the learning value is updated so as to be suitable for this driving, so that a good learning value that is adapted to the driving manner of the driver is updated, and excellent responsiveness is achieved. In addition, the ignition timing control can be executed, and the ignition timing is not retarded beyond the necessary retardation amount, so that the deterioration of fuel consumption and exhaust emission can be prevented.

In the above-described embodiment, the entire operation region is divided into five regions, and when knocking occurs in the three regions when the engine is heavily loaded, a skip-like retard and a subsequent feedback-like retard are executed. At the same time, the learning of the skip-like retard amount is performed, but, of course, the ignition timing control including such learning is performed in all the operation regions in which the ignition timing is retarded when knocking occurs. It may be executed.

[0024]

As described above, according to the ignition timing control apparatus according to the present invention, the ignition timing retarding means suppresses knocking to a predetermined level or less when knocking occurs from the basic ignition timing by the necessary retarding amount at this time. After being skipped by the first retard amount so as to be retarded, the retard is further retarded by the second retard amount that is further increased and decreased in a feedback manner, and the calculation means determines whether the second retard amount has increased or decreased. Increase or decrease according to at least the second
When the retard amount increases, a second retard amount smoothing value that increases more gently is calculated, and the first retard amount updating means determines that the second retard amount smooth value calculated by the calculating means is within a predetermined range. In order to update the first retard amount on the increasing side when the vehicle exceeds the predetermined range and decrease on the decreasing side when the vehicle becomes smaller than the predetermined range, the driving in the transient state in which the knocking occurrence situation is greatly deteriorated even once by the driver. When the operation is performed, the first
As in the past, the amount of retard is updated.The next time normal operation is performed, the ignition timing is not unnecessarily retarded and fuel consumption and exhaust emissions do not deteriorate. Good updating is realized. In addition, the accuracy of learning can be improved when the driver drives the vehicle in the transition state very frequently, as compared with the case where the learning is stopped in the transition state.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view of an internal combustion engine equipped with an ignition timing control device according to the present invention.

FIG. 2 is a first flowchart for ignition timing control.

FIG. 3 is a second flowchart for updating a learning value.

FIG. 4 is a first map for determining a basic ignition timing.

FIG. 5 is a second map for determining a maximum retard amount.

FIG. 6 is a map showing each operation area.

FIG. 7 is a time chart of a retard amount θK and a smoothing value θS.

FIG. 8 is an explanatory diagram for determining an ignition timing in a learning area.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 3 ... Spark plug 9 ... Knocking sensor 13 ... Air flow meter 18 ... Rotation angle sensor 20 ... Electronic control device

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02P 5/152

Claims (1)

(57) [Claims] When the knocking occurs, the knocking is suppressed to a predetermined level or less. After the basic ignition timing is retarded by a first delay amount so as to be retarded from the basic ignition timing by a necessary retard amount at this time, furthermore, The second is increased or decreased by feedback
An ignition timing retarding means for retarding according to the retardation amount;
Calculating means for calculating a second retardation smoothing value which increases or decreases in accordance with the increase or decrease in the retardation amount and which increases at least more gently when the second retardation amount increases; (2) When the smoothed value of the retard amount increases beyond a predetermined range, the first retard amount is increased, and when the smoothed value of the retard angle becomes smaller than the predetermined range, the first retard amount is updated to a decreasing side.
And a retard amount updating means.