JP2011247108A - Knocking control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To quickly return the ignition timing to a proper state during erroneous lag in knocking control of an internal combustion engine.SOLUTION: In an erroneous lag state (YES in S144), an advance amount θa for each period is increased by an erroneous-lag-time map Map2 (S148) in order to enhance an advance speed of the ignition timing. By this, the ignition timing can be quickly returned to a proper state even if the ignition timing is in the erroneous lag state for some reasons. The erroneous lag state is eliminated after the return (NO in S144) and the advance amount θa having the normal magnitude is used by a normal-time map Map1 (S146). Thus, it is returned to the normal advance speed and returned to a stable knocking control state. In addition, the advance speed may be enhanced by reducing the advance period in the erroneous lag state. Further, the advance amount θa and the advance period are changed according to the rotational frequency of the internal combustion engine and the load of the internal combustion engine in order to enhance the knocking-control stability.

Description

  The present invention determines a knocking state based on a vibration state detected by a knock sensor provided in an internal combustion engine. When it is determined that the engine is in the knocking state, the ignition timing is retarded and the knocking state is determined. If not, the present invention relates to an internal combustion engine knocking control device that performs ignition timing feedback control processing by advancing the ignition timing.

A knock control system that appropriately controls the knocking state by adjusting the ignition timing of the internal combustion engine is known (see, for example, Patent Documents 1 to 4).
In Patent Document 1, in order to prevent a decrease in the output of the internal combustion engine due to a difference in the octane number of the fuel, the return speed at the time of non-knocking in the ignition timing correction amount is set when the ignition timing is behind the first reference ignition timing. Fast and slow on the advancing side. As a result, the retard correction amount unnecessary for suppressing knocking of any fuel is minimized to prevent a decrease in the output of the internal combustion engine and improve the acceleration performance.

  In Patent Document 2, when the ignition timing is returned in the advance direction from the retarded state based on knocking, the shift ratio in the advance direction is reduced as the advance angle is increased. Therefore, when approaching the knocking limit, it is possible to shift in the advance direction relatively slowly, and an improvement in energy efficiency and a reduction in knocking are achieved simultaneously by the operation at the ignition timing close to the knocking limit.

  In Patent Document 3, knock strength is calculated using weighting for each frequency of knocking vibration, and the ignition timing is retarded more largely as the knock strength increases in accordance with the knock strength. This makes it possible to increase the time until the advance angle returns for large knocking to protect the engine, and to shorten the return time for small knocking to improve fuel efficiency.

  In Patent Document 4, when the advance angle correction is executed at the end of acceleration in order to return from the ignition timing retard, the return advance speed is set to a faster return speed than at the normal time. As a result, when knocking occurs during acceleration, the ignition timing is retarded to prevent recurrence of knocking.After the acceleration is completed, the return speed for correcting the advance of the knocking retardation correction amount is set. Since the return speed is faster than normal, it is possible to prevent the output of the internal combustion engine from decreasing and satisfy the acceleration performance. When it is not during acceleration, it is possible to prevent knocking recurrence because it is a normal return speed.

Japanese Patent Laid-Open No. 06-129334 (5th page, FIGS. 1 and 6) Japanese Patent Laying-Open No. 2005-030384 (page 4-5, FIG. 3) Japanese Patent Laid-Open No. 05-079440 (page 2-3, FIGS. 2 and 4) JP 11-117844 A (page 3-4, FIG. 2-4)

  In the ignition timing control of an internal combustion engine, an ignition timing may be erroneously retarded for some reason. For example, when the type of fuel is changed, especially when switching to a fuel with a high octane number, the frequency of knocking will be lower than before, resulting in a temporary delay state and a decrease in internal combustion engine output. To do.

  Such an erroneous retard state is not determined in Patent Document 1, but a reference ignition timing is set, and when the ignition timing is on the retard side, the return speed is increased, and on the advance side, the return speed is decreased. Only. In addition, the reference ignition timing is merely set as a threshold value, and the return speed is reduced if the ignition timing is advanced from the reference ignition timing in spite of the erroneous retardation state. Returning to an appropriate knock control state will be delayed.

Furthermore, when an erroneous retardation state has occurred for some reason other than fuel, it is not possible to sufficiently cope with only the reference ignition timing set corresponding to the type of fuel.
Since Patent Documents 2 to 4 are not processing performed by determining an erroneous retardation state, the same control is executed at the time of erroneous retardation and when it is not. For this reason, it is executed even when the engine is in a normal retarded state that is not in the wrong retarded state. There is a limit to quickly returning the time.

  An object of the present invention is to quickly return the ignition timing to an appropriate state at the time of erroneous retardation in the internal combustion engine knocking control.

In the following, means for achieving the above-mentioned purpose, and its operation and effect are described.
The internal combustion engine knocking control apparatus according to claim 1 determines the knocking state based on a vibration state detected by a knock sensor provided in the internal combustion engine, and determines the ignition timing when it is determined that the knocking occurrence frequency is high. An internal combustion engine knocking control apparatus that performs feedback control processing of the ignition timing by advancing the ignition timing when retarding and it is not determined that the occurrence frequency of knocking is high, is the ignition timing in an erroneously retarded state? An advance speed adjusting means for changing the advance speed of the ignition timing depending on whether or not is provided.

  In this way, the advance speed adjusting means can change the advance speed of the ignition timing depending on whether or not the ignition timing is in the erroneous retard state, so that the advance speed is increased at the time of the erroneous retard than the normal time. You can change the advance speed. As a result, the ignition timing can be quickly returned to an appropriate state even if the ignition timing is erroneously retarded for some reason.

  The internal combustion engine knocking control apparatus according to claim 2, wherein the advance speed adjusting means includes an erroneous retardation detection means for detecting an erroneous retardation state of the ignition timing; An advance speed increasing means is provided for increasing the advance speed of the ignition timing when the erroneous retard angle detecting means detects that it is in an erroneous retard state.

The advance speed increasing means can increase the advance speed of the ignition timing at the time of erroneous retardation, and can quickly return the ignition timing to an appropriate state.
The internal combustion engine knocking control apparatus according to claim 3, wherein in the internal combustion engine knocking control apparatus according to claim 2, the erroneous retardation detection means adjusts an ignition timing according to a knocking state in the feedback control process. An erroneous retardation state of the ignition timing is detected based on the timing feedback correction value.

  Whether or not the ignition timing is erroneously retarded appears in the state of the ignition timing feedback correction value including the history. For this reason, the erroneous retard detection means can easily detect the presence or absence of an erroneous retard state of the ignition timing by using the ignition timing feedback correction value.

In addition, since a normal element calculated by the ignition timing feedback control is used without using a special element as described above, it can be easily applied to various types of knock control.
The internal combustion engine knocking control apparatus according to claim 4, wherein the erroneous retard angle detection means is such that the ignition timing feedback correction value is continuously present on the advance angle request side. When the knocking occurrence frequency detected by the knock sensor is low, it is detected that the ignition timing is in an erroneous retardation state.

  As described above, when the ignition timing feedback correction value is continuously present on the advance angle request side and the occurrence of knocking by the detection of the knock sensor is low, the combustion state of the internal combustion engine almost causes knocking. This indicates that the ignition timing is retarded excessively, that is, an erroneous retarded state.

  As described above, since the erroneous retardation state appears in the ignition timing feedback correction value, the erroneous retardation detection means can easily detect the presence or absence of the erroneous retardation state of the ignition timing using the ignition timing feedback correction value.

  The internal combustion engine knocking control apparatus according to claim 5, wherein the erroneous retardation detection means has a fluctuation suppression processing value of the ignition timing feedback correction value that is an advance angle request side. When the difference between the fluctuation suppression processing value and the current ignition timing feedback correction value is small, it is detected that the ignition timing is in an erroneous retardation state.

  Thus, the state in which the ignition timing feedback correction value fluctuation suppression processing value exists on the advance angle request side indicates the state in which the ignition timing feedback correction value continues to exist on the advance angle request side. The state where the difference between the fluctuation suppression processing value and the current ignition timing feedback correction value is small corresponds to the state where the frequency of occurrence of knocking by the detection of the knock sensor is low.

Therefore, the combustion state of the internal combustion engine shows that the ignition timing is excessively retarded, i.e., that it is in a false retarded state although knocking hardly occurs.
As described above, since the erroneous retardation state appears in the ignition timing feedback correction value, the erroneous retardation detection means easily determines whether there is an erroneous retardation state of the ignition timing using the ignition timing feedback correction value and its history. It can be detected.

  In the internal combustion engine knocking control device according to claim 6, in the internal combustion engine knocking control device according to any one of claims 2 to 5, the advance of the ignition timing is periodically executed, and the advance speed is increased. The increasing means increases the advance speed of the ignition timing by one or both of an increase in the advance amount per cycle and a shortening of the advance period.

  The advance speed of the ignition timing can be adjusted by adjusting the advance amount for each cycle or by adjusting the advance period. Accordingly, the advance speed of the ignition timing can be easily increased at the time of erroneous retardation by either or both of increasing the advance amount for each period and shortening the advance period.

  The internal combustion engine knocking control apparatus according to claim 7, wherein either or both of the advance period of the ignition timing and the advance amount for each period are the internal combustion engine. It is characterized in that it is adjusted based on one or both of the rotational speed and the load.

  In the internal combustion engine knocking control device, either or both of the advance period of the ignition timing and the advance amount of each period are adjusted to increase the advance speed of the ignition timing at the time of erroneous retard as described above. In addition, as in the present invention, it may be further adjusted based on one or both of the rotational speed and the load of the internal combustion engine.

  As a result, in addition to being able to quickly return the ignition timing to an appropriate state at the time of erroneous retardation, it is possible for stable knocking control to reflect the operating state of the internal combustion engine at both normal time and erroneous retardation. Appropriate ignition timing adjustment is possible.

  An internal combustion engine knocking control apparatus according to an eighth aspect is characterized in that, in the internal combustion engine knocking control apparatus according to the seventh aspect, the advance period of the ignition timing is lengthened as the load on the internal combustion engine increases.

  When the load of the internal combustion engine is high, the frequency of knocking tends to increase rapidly even with a slight change in the ignition timing. For this reason, as the load on the internal combustion engine is higher, the advance period of the ignition timing is lengthened, so that the advance speed is slowed down so that stable knocking control is possible.

  The internal combustion engine knocking control device according to claim 9 is characterized in that, in the internal combustion engine knocking control device according to claim 7 or 8, the advance amount of the ignition timing for each cycle is reduced as the load of the internal combustion engine is higher. And

  When the load of the internal combustion engine is high, the frequency of knocking tends to increase rapidly even with a slight change in the ignition timing. For this reason, as the load on the internal combustion engine is higher, the advance amount per cycle is reduced, so that the advance speed is slowed down so that stable knocking control is possible.

  The internal combustion engine knocking control apparatus according to claim 10, wherein the ignition timing advance angle for each cycle is decreased as the rotational speed of the internal combustion engine is decreased in the internal combustion engine knocking control apparatus according to any one of claims 7 to 9. It is characterized by reducing the amount.

  The knocking occurrence frequency may increase on the side where the internal combustion engine speed is small. For this reason, the smaller the internal combustion engine speed is, the smaller the advance amount of the ignition timing for each cycle, and by repeating the advance processing little by little, the advance is made while avoiding the increase in knocking as much as possible. Decrease can be prevented and acceleration can be improved.

  An internal combustion engine knocking control apparatus according to an eleventh aspect is characterized in that, in the internal combustion engine knocking control apparatus according to the tenth aspect, the advance period of the ignition timing is shortened as the rotational speed of the internal combustion engine is small.

  Further, the smaller the internal combustion engine speed, the smaller the advance amount of the ignition timing per cycle, and the shorter the advance cycle of the ignition timing, the fine advance processing may be repeated. As a result, by advancing while avoiding an increase in knocking as much as possible, a reduction in the output of the internal combustion engine can be prevented and acceleration can be improved.

1 is a block diagram of an internal combustion engine and a knocking control device of a first embodiment. 4 is a flowchart of knock control ignition timing feedback processing according to the first embodiment. 5 is a flowchart of ignition timing advance processing according to the first embodiment. (A), (b) The graph showing the structure of the advance amount map of Embodiment 1. FIG. 3 is a timing chart illustrating an example of processing according to the first embodiment. 7 is a flowchart of ignition timing advance processing according to the second embodiment. (A), (b) The graph showing the structure of the advance angle period map of Embodiment 3. FIG.

[Embodiment 1]
The internal combustion engine 2 and its knocking control device are shown in the block diagram of FIG. The internal combustion engine 2 is controlled by an electronic control unit (hereinafter referred to as “ECU”) 4, and this ECU 4 executes the processing of FIGS. 2 and 3 described later as an internal combustion engine knocking control device.

  The internal combustion engine 2 shown in FIG. 1 is a port injection spark ignition type in-line four-cylinder gasoline engine mounted on a vehicle for driving the vehicle. FIG. 1 shows one cylinder. It may be an internal combustion engine having another number of cylinders such as 6 cylinders or 8 cylinders, or a V-type internal combustion engine. The fuel injection may be an in-cylinder injection type in which the fuel is directly injected into the cylinder.

  Air is supplied to each combustion chamber 6 of the internal combustion engine 2 through an intake passage 8 including a surge tank 8a and a branch pipe 8b, and from the fuel injection valve 10 provided for each cylinder, An air-fuel mixture is formed by injecting fuel into the tank.

  The air-fuel mixture formed in the combustion chamber 6 in this way is ignited by the spark of the spark plug 12 at the ignition timing, so that the air-fuel mixture burns, the piston 14 is pushed down, and the crankshaft which is the output shaft 16 is rotated. The air-fuel mixture after combustion is discharged as exhaust from the combustion chamber 6 to the exhaust port 18a, and is discharged to the outside through an exhaust passage 18 having an exhaust purification catalyst and a muffler.

  Here, both the intake valve 20 that opens and closes at the intake port 8c and the exhaust valve 22 that opens and closes at the exhaust port 18a are driven at a constant valve operating angle. The intake valve 20 may be provided with a variable valve timing mechanism so that the valve operating angle (or the maximum valve lift amount) can be varied, or the on-off valve timing can be advanced or retarded. The exhaust valve 22 may also be capable of advancing and retarding the on-off valve timing.

  The amount of intake air distributed from the intake passage 8 to the combustion chamber 6 of each cylinder is adjusted by the ECU 4 controlling the opening of the throttle valve 26 in accordance with the accelerator operation amount ACCP, which is the depression amount of the accelerator pedal 24. The When the valve operating angle (or the maximum valve lift amount) of the intake valve 20 is made variable by the variable valve mechanism, each cylinder is adjusted by adjusting the valve operating angle (or the maximum valve lift amount) of the intake valve 20. The amount of intake air distributed to the combustion chamber 6 is adjusted. In this case, the throttle valve 26 is normally controlled to be fully opened, and the internal combustion engine 2 is operated.

  As described above, the ECU 4 executes ignition timing control and other processes in addition to the fuel injection amount, injection timing, and intake air amount of the internal combustion engine 2. For these processes, the ECU 4 detects signals from the engine speed sensor 28, the cooling water temperature sensor 30, the throttle opening sensor 32, the intake air amount sensor 34, the accelerator operation amount sensor 36, the cam position sensor 38, the knock sensor 40, and the like. Is entered.

  The engine speed sensor 28 is the internal combustion engine speed NE corresponding to the rotation of the crankshaft 16, the coolant temperature sensor 30 is the coolant temperature THW as the internal combustion engine temperature, the throttle opening sensor 32 is the throttle valve opening TA, The intake air amount sensor 34 detects the intake air amount GA, and the accelerator operation amount sensor 36 detects the accelerator operation amount ACCP. Further, the cam position sensor 38 is attached to the cam angle of the intake cam that drives the intake valve 20, and the knock sensor 40 is attached to the cylinder block of the internal combustion engine 2, and generates a knock signal (here, a voltage signal: V).

  The ECU 4 executes various controls based on these signals, data stored in the internal memory, its own calculation result, and the like. That is, the ignition timing by the spark plug 12, the fuel injection amount and injection timing by the valve opening control of the fuel injection valve 10, the opening adjustment of the throttle valve 26 described above (if the variable valve mechanism is employed, the intake valve 20 Control such as valve working angle or maximum valve lift adjustment, opening / closing valve timing) is executed.

The knock control ignition timing feedback process executed by the ECU 4 is shown in the flowchart of FIG. 2, and the ignition timing advance process is shown in the flowchart of FIG.
The knock control ignition timing feedback process (FIG. 2) is a process repeatedly executed at a constant time period or a constant crank angle period. The ignition timing advance processing (FIG. 3) is processing that is repeatedly executed at a constant time period. The steps in the flowchart corresponding to the individual processing contents are represented by “S˜”.

  When the knock control ignition timing feedback process (FIG. 2) is started, the knocking state detection content is first read (S102). In the knocking state detection, the contents of the knocking presence / absence determination process separately performed by the ECU 4 are read based on the detection value of the knock sensor 40.

  This knocking presence / absence determination processing is for determining the frequency of occurrence of knocking obtained by the detection of the knock sensor 40. For example, the knock intensity N is calculated from the detected value of the knock sensor 40 in a predetermined crank angle region corresponding to each cylinder, and if the knock intensity N is larger than the determination value, it is assumed that the occurrence frequency of knocking is high. If it is smaller, it is determined that there is no knocking.

  Alternatively, in addition to the determination of the magnitude of the knock intensity N, the correlation between the knock vibration intensity waveform obtained from the detection value of the knock sensor 40 by the vibration waveform analysis and the knock vibration intensity waveform model may be obtained and determined. That is, if knock magnitude N is larger than the determination value and the correlation is strong, it is determined that knocking frequency is high, and “no knocking” is determined, otherwise “no knocking” is determined.

  Next, the content of such knocking presence / absence determination processing is determined (S104). If the occurrence of knocking is high from the detection result and it is determined that “knocking is present”, the ignition timing feedback correction value aks is corrected to the retard side (S106). This ignition timing feedback correction value aks is used to set a retard amount with respect to the required ignition timing (° CA: CA represents the crank angle) which is the actual ignition timing. Therefore, the ignition timing feedback correction value akcs is increased and corrected by a delay amount set in advance for knock control, thereby executing a delay corresponding to “with knocking” with respect to the required ignition timing. can do.

The retard amount for knock control may be a constant value, or may be a retard amount adjusted according to the knocking state or the operating state of the internal combustion engine 2.
After step S106 or after determining that “no knocking” is obtained in step S104, an annealing value akcssm of the ignition timing feedback correction value akcs is calculated (S108).

  This annealing value akcssm is a fluctuation suppression processing value of the ignition timing feedback correction value akcs. That is, it is a value calculated by performing processing for suppressing fluctuations in the ignition timing feedback correction value akcs. Such fluctuation suppression processing is performed by, for example, first-order lag processing, moving average processing, or the like. In step S108, the movement between the ignition timing feedback correction value aks and the current ignition timing feedback correction value aks for a predetermined period in the past. An average value is calculated by the averaging process, and this average value is set as the smoothed value akcssm.

Next, it is determined whether or not the annealing value akcssm is in the learning region (S110).
Here, when the smoothed value aksssm is in the advance learning region, the knock control learning value aggnk is changed by a predetermined amount to the advance side, and learning to the advance side is performed (S112).

  If the annealing value akcssm is in the retard learning region, the knock control learning value aggnk is changed by a predetermined amount to the retard side and learning to the retard side is performed (S114). If none of the learning areas falls, the knock control learning value agnkk is not changed.

When the knock control learning value agknk is changed as described above, the ignition timing feedback correction value akcs is changed so as to cancel out the change.
As described above, after the process of step S112 or step S114, or when it is not in the learning region, the required ignition timing is set to the reference ignition timing (for example, the most retarded ignition timing), the ignition timing feedback correction value aks, and the knock. This is done based on the control learning value agknk (S116).

And once this processing is exited, the above-mentioned processing is repeated periodically thereafter.
Next, the ignition timing advance processing (FIG. 3) for periodically advancing the ignition timing feedback correction value akcs will be described.

  When this processing is started, first, it is determined whether or not the advance timing is present (S142). Since the advance angle of the ignition timing feedback correction value aks is performed at a constant time period, it is determined here whether or not a time A (ms) set in advance as an advance angle period has elapsed since the previous execution of this process. It is determined whether it is timing.

If it is not the advance angle timing (NO in S142), the present process is left as it is, and no substantial process is performed.
If it is the advance angle timing (YES in S142), it is next determined whether or not there is an erroneous retardation state (S144). Whether or not it is in the erroneous retardation state is determined by whether or not both of the following conditions 1 and 2 are satisfied.

Condition 1: An annealing value akcssm exists in the advance angle learning region. (This indicates that the ignition timing feedback correction value aks is continuously present on the advance angle request side.)
Condition 2: The annealing value akcssm and the ignition timing feedback correction value akcs are close to each other. (For example, a state where | akcssm−akcs | ≦ proximity reference value B)
If these conditions 1 and 2 are satisfied, the current ignition timing setting state is not stable, the knocking occurrence frequency is low, and the knocking occurrence frequency is still low. It shows a state in which the timing continues to shift to the advance side. That is, it shows a state in which the angle is retarded for some reason.

  If either one or both of these conditions 1 and 2 are not satisfied (NO in S144), the advance amount θa is calculated based on the internal combustion engine speed NE from the normal time map Map1 (S146).

If both of the above conditions 1 and 2 are satisfied (YES in S144), the advance amount θa is calculated based on the internal combustion engine speed NE based on the erroneous retard angle map Map2 (S148).
Here, an example of the normal time map Map1 and the erroneous retardation time map Map2 is shown in FIGS.

  Each of the maps Map1 and Map2 sets the advance amount θa by dividing the internal combustion engine speed NE (rpm) into three regions. Here, in both the normal time map Map1 shown in FIG. 4A and the erroneous retardation time map Map2 shown in FIG. 4B, the advance amount θa is increased as the internal combustion engine speed NE increases. Yes.

  That is, in the normal time map Map1, the advance amount θa = θ11 when NE = 1500 rpm, NE = 1500 rpm to less than 3000 rpm, the advance amount θa = θ12, NE = 3000 rpm or more, the advance amount θa = θ13, There is a relationship of θ11 <θ12 <θ13.

  In the erroneous retardation angle map Map2, the advance amount θa = θ21 when NE = 1500 rpm, the advance amount θa = θ22 when NE = 1500 rpm to less than 3000 rpm, and the advance amount θa = θ23 when NE = 3000 rpm or more. , Θ21 <θ22 <θ23.

  In the erroneous retardation time map Map2, compared with the normal time map Map1, θ21> θ11 in the rotation speed region below NE = 1500 rpm, and θ22> θ12 in the rotation speed region from NE = 1500 rpm to less than 3000 rpm. . Note that when NE = 3000 rpm or more, θ23 = θ13.

  Thus, after the advance amount θa is calculated in step S146 or step S148, the ignition timing feedback correction value aks is advanced by the advance amount θa (S150).

  Therefore, in the region of NE <3000 rpm, the advance amount θa is made larger than usual in the erroneous retardation state. That is, the ignition timing feedback correction value akcs is increased in speed to change to the advance side, the smoothing value akcssm is also learned to advance side, and the ignition timing can be changed to the advance side more quickly than usual. become.

  Thus, the present process is temporarily exited. Thereafter, for each period of the advance timing determined in step S142, the advance of the ignition timing feedback correction value akcs by the advance amount θa obtained in step S146 or step S148 is repeated.

  FIG. 5 is a timing chart showing an example of ignition timing control according to the present embodiment. Before the timing t0, as indicated by the solid line, the ignition timing is appropriately controlled in the vicinity of the ignition timing k1, which is the knock limit.

It is assumed that the knock limit is changed from the ignition timing k1 to the ignition timing k2 for some reason due to a change in the fuel type at the timing t0. Therefore, the knocking frequency decreases.
For this reason, after the timing t0, the retard processing (S106) of the ignition timing feedback correction value aks is not performed, and only the advance by the ignition timing advance processing (FIG. 3) is repeated.

  Initially, one or both of the above-described conditions 1 and 2 are not satisfied (NO in S144), and the ignition timing feedback correction value akcs is advanced by the advance amount θa obtained from the normal time map Map1 ( S146 and S150) are repeated (t0).

However, by repeating only such an advance angle to the ignition timing feedback correction value akcs, both the conditions 1 and 2 are satisfied (t1).
As a result, it is determined that there is an erroneous retardation state (YES in S144), and the advance angle (S148, S150) based on the advance angle amount θa obtained from the erroneous retardation time map Map2 is repeated (t1 to t1).

  Therefore, as indicated by the solid line, the ignition timing rapidly advances and approaches the ignition timing k2, and reaches the ignition timing k2 after a short time (t2). Immediately after this, due to the increase in the knocking frequency, the condition 2 is not satisfied first, and thereafter, the condition 1 is not satisfied. As a result, a state where both the conditions 1 and 2 are satisfied does not occur (NO in S144).

  As a result, immediately after the timing t2, the ignition timing feedback correction value aks is returned to the normal control state in which the advance angle (S146, S150) by the advance amount θa obtained from the normal time map Map1 is repeated.

  As a comparative example, let us consider a case where the normal-time map Map1 is continuously used as a map for calculating the advance amount θa even if the erroneous retardation state is determined without determining the erroneous retardation state. In this case, as indicated by the alternate long and short dash line in FIG. 5, the advance speed of the ignition timing does not change, so the arrival timing (t3) to the ignition timing k2 is delayed. For this reason, an inappropriate retarded state (t2 to t3) in which ignition is not performed at an ignition timing close to the knock limit continues for a long time.

Compared to this, in the ignition timing control of the present embodiment, an inappropriate retarded state is shortened.
In the above-described configuration, the relationship with the claims corresponds to the ECU 4 as the internal combustion engine knocking control device and the advance speed adjusting means. The ignition timing advance processing (FIG. 3) corresponds to the processing as the advance speed adjusting means, the false delay angle detecting means, and the advance speed increasing means. Step S148 corresponds to the processing as the advance angle speed increasing means for the processing as the angle detecting means.

According to the first embodiment described above, the following effects can be obtained.
(1) By the ignition timing advance processing (FIG. 3), the advance angle speed is increased by increasing the advance amount θa of the ignition timing for each cycle by the erroneous retard time map Map2 in the erroneous retard state. As a result, the ignition timing can be quickly returned to an appropriate state even if the ignition timing is erroneously retarded for some reason.

  After the return, the erroneous retardation state is resolved (NO in S144), and the normal advance map θa1 is used to return to the normal advance speed by using the normal advance amount θa. This makes it possible to return to a stable knock control state.

  (2) The erroneous retardation state is a determination based on conditions 1 and 2 in step S144. That is, the erroneous retardation state is determined only by the state of the ignition timing feedback correction value akcs and the smoothing value akcssm.

  The annealing value akcssm is calculated from the history of the ignition timing feedback correction value akcs. As described above, since the erroneously retarded state of the ignition timing is detected based on the ignition timing feedback correction value aks, the erroneously retarded state can be easily detected.

  Moreover, since this ignition timing feedback correction value aks is a main element and not a special element in the knock control ignition timing feedback processing, it can be easily applied to various types of knock control.

  (3) In both the normal time map Map1 and the erroneous retard angle time map Map2, the advance amount θa is adjusted according to the internal combustion engine speed NE, and the advance amount θa is reduced on the side where the internal combustion engine speed NE is smaller. It is small.

  The frequency of knocking may increase on the side where the engine speed NE is small. For this reason, the smaller the internal combustion engine speed NE, the smaller the advance amount θa of the ignition timing for each cycle, so that the ignition timing advance processing is repeated little by little. As a result, the ignition timing can be advanced while avoiding an increase in knocking as much as possible, and stable knocking control can be performed both in the normal time and in the erroneous delay time. Therefore, it is possible to improve the acceleration performance by preventing the output of the internal combustion engine from decreasing.

[Embodiment 2]
The present embodiment is different from the first embodiment in that the ignition timing advance processing shown in FIG. 6 is periodically executed instead of the ignition timing advance processing (FIG. 3). Other configurations are the same as those in the first embodiment.

  The ignition timing advance processing (FIG. 6) will be described. When this process is started, it is first determined whether or not an erroneous retardation state is present (S240). Whether or not it is in the erroneous retardation state is determined by whether or not the conditions 1 and 2 described in the first embodiment are satisfied.

  If either or both of the conditions 1 and 2 are not satisfied (NO in S240), the advance period is set to the normal period (S242). That is, the advance timing interval determined in the next step S246 is set to a normal interval.

  If both conditions 1 and 2 are satisfied (YES in S240), the advance period is set to a short period (S244). That is, the advance timing interval determined in the next step S246 is set to be shorter than the normal interval.

  When the advance period is set in step S242 or step S244, it is next determined whether or not there is an advance timing (S246). That is, it is determined whether or not the timing is the advance timing in the advance cycle set in step S242 or step S244.

If it is not the advance angle timing (NO in S246), the present process is left as it is, and no substantial process is performed.
If it is the advance timing (YES in S246), the advance amount θa is calculated based on the internal combustion engine speed NE from the normal time map Map1 (S248). This normal time map Map1 is as shown in FIG.

Next, the ignition timing feedback correction value akcs is advanced by the advance amount θa (S250). Thus, the present process is temporarily exited.
Thereafter, the advance timing of the ignition timing feedback correction value akcs by the advance amount θa is repeated every cycle of the advance timing determined in step S246. Then, the cycle of the advance timing is made shorter than normal at the time of erroneous retardation, so that at the time of erroneous retardation, the advance of the ignition timing feedback correction value aks is a rapid advance speed than at the normal time.

  As a result, the map used for setting the advance amount θa has only one normal time map Map1, but as in the state shown in FIG. The ignition timing can be quickly changed to the advance side.

  In the above-described configuration, the relationship with the claims corresponds to the ECU 4 as the internal combustion engine knocking control device and the advance speed adjusting means. The ignition timing advance processing (FIG. 6) corresponds to the processing as the advance speed adjusting means, the erroneous retard angle detecting means, and the advance speed increasing means, and the processing for determining whether or not the erroneous retard state is in step S240 is erroneous. Step S244 corresponds to the processing as the advance angle speed increasing means for the processing as the angle detecting means.

  According to the second embodiment described above, even when the normal time map Map1 is continuously used at the time of erroneous delay, the same effect as the first embodiment is produced by shortening the advance period. Can be made.

[Embodiment 3]
Both the normal time map Map1 and the erroneous retard angle map Map2 used in the first embodiment have a configuration in which the advance amount θa changes in accordance with the internal combustion engine speed NE. In addition to Map2, an advance period map shown in FIG. 7A may be applied. As a result, it is possible to adopt a configuration in which both the advance amount θa and the advance period change in accordance with the internal combustion engine speed NE.

  In the second embodiment, the advance period map of FIGS. 7A and 7B may be switched and used. That is, in the ignition timing advance processing (FIG. 6), at the normal time (NO in S240), the normal time advance cycle map of FIG. 7 (a) is used in step S242. In the erroneous retardation state (YES in S240), the erroneous retardation angle advance period map shown in FIG. 7B is used in step S244. The relationship between the maps in FIGS. 7A and 7B is the period T21 <T11, T22 <T12, and T23 <T13, and the error delay time advance period map is compared with the normal time advance period map. However, the advance period is shortened.

This makes it possible to increase the advance speed of the ignition timing by shortening the advance period compared to the normal time at the time of erroneous retardation.
According to the third embodiment described above, the effects of the first or second embodiment are produced.

  In addition to this, in the maps of FIGS. 7A and 7B, the advance period of the ignition timing is shortened as the internal combustion engine speed NE is smaller. For this reason, since the fine advance processing can be repeated on the side where the internal combustion engine rotational speed NE is small, it is possible to advance while avoiding an increase in knocking as much as possible.

As a result, stable knocking control can be performed both during normal times and during erroneous retardation. Therefore, it is possible to improve the acceleration performance by preventing the output of the internal combustion engine from decreasing.
[Other embodiments]
In each of the above embodiments, when the state is changed from the normal time to the erroneous retardation state, both the advance amount of the ignition timing and the shortening of the advance period at the erroneous retardation time may be executed. .

  In each of the above embodiments, the advance amount θa and the advance period are changed according to the internal combustion engine speed NE, but the advance amount θa and the advance period are changed according to the load of the internal combustion engine. Also good. For example, if the internal combustion engine load factor kl is high, the advance amount θa is decreased or the advance period is increased.

  Here, the internal combustion engine load factor kl is one index indicating the load of the internal combustion engine, and the ratio of the actual intake air amount (GA / NE) per revolution to the reference maximum intake air amount per revolution of the internal combustion engine. (%). As such a load, in addition to the internal combustion engine load factor kl, the intake pressure in the surge tank may be measured and used. Further, the advance amount θa and the advance angle cycle may be changed according to both the internal combustion engine speed NE and the load of the internal combustion engine.

  When the internal combustion engine load factor kl is high, the range of the ignition timing at which an appropriate knock level can be obtained is narrowed. Therefore, when the internal combustion engine load factor kl is high, even if the ignition timing is slightly advanced, the frequency of occurrence of knocking is rapidly increased. It tends to increase. For this reason, as the load factor kl of the internal combustion engine is higher, the advance amount θa per cycle is reduced, so that the advance speed is slowed down so that stable knocking control can be performed. Alternatively, as the load factor kl of the internal combustion engine is higher, the advance period of the ignition timing is lengthened, thereby making it possible to perform stable knocking control by slowing the advance speed.

  The maps shown in FIGS. 4 and 7 change the advance amount θa and the advance period in a stepwise manner in accordance with the internal combustion engine speed NE, but may be changed continuously. As described above, the same applies when the advance amount θa and the advance period are changed in accordance with the load of the internal combustion engine.

  DESCRIPTION OF SYMBOLS 2 ... Internal combustion engine, 4 ... ECU, 6 ... Combustion chamber, 8 ... Intake passage, 8a ... Surge tank, 8b ... Branch pipe, 8c ... Intake port, 10 ... Fuel injection valve, 12 ... Spark plug, 14 ... Piston, 16 ... crankshaft, 18 ... exhaust passage, 18a ... exhaust port, 20 ... intake valve, 22 ... exhaust valve, 24 ... accelerator pedal, 26 ... throttle valve, 28 ... engine speed sensor, 30 ... cooling water temperature sensor, 32 ... throttle Opening sensor 34... Intake air amount sensor 36. Accelerator operation amount sensor 38. Cam position sensor 40. Knock sensor

Claims (11)

When the knocking state is determined based on the vibration state detected by the knock sensor provided in the internal combustion engine, and when it is determined that the knocking occurrence frequency is high, the ignition timing is retarded, and it is not determined that the knocking occurrence frequency is high Is an internal combustion engine knocking control device that performs feedback control processing of ignition timing by advancing the ignition timing,
An internal combustion engine knocking control device comprising an advance speed adjusting means for changing an advance speed of the ignition timing depending on whether or not the ignition timing is in a false retard state. The internal combustion engine knocking control device according to claim 1, wherein the advance speed adjusting means is
An erroneous retard detection means for detecting an erroneous retard state of the ignition timing;
Advance speed increasing means for increasing the advance speed of the ignition timing when the erroneous retard angle detecting means is detected to be in an erroneous retard state;
An internal combustion engine knocking control device comprising: 3. The internal combustion engine knocking control device according to claim 2, wherein the erroneous retard detection means detects an erroneous ignition timing based on an ignition timing feedback correction value that adjusts an ignition timing according to a knocking state in the feedback control process. An internal combustion engine knocking control apparatus characterized by detecting a state. 4. The internal combustion engine knocking control device according to claim 3, wherein the erroneous retardation detection means has the ignition timing feedback correction value continuously present on the advance angle request side, and a knocking occurrence frequency detected by the knock sensor is detected. An internal combustion engine knocking control apparatus that detects that the ignition timing is in a false retard state when the ignition timing is low. 4. The internal combustion engine knocking control device according to claim 3, wherein the erroneous retardation detection means has a fluctuation suppression processing value of the ignition timing feedback correction value on an advance angle request side, and the fluctuation suppression processing value and the current An internal combustion engine knocking control device that detects that an ignition timing is in a false retard state when a difference from an ignition timing feedback correction value is small. In the internal combustion engine knocking control device according to any one of claims 2 to 5, the advance of the ignition timing is periodically executed, and the advance speed increasing means is configured to increase the advance amount for each period. An internal combustion engine knocking control apparatus, wherein the advance speed of the ignition timing is increased by one or both of shortening an advance period. 7. The internal combustion engine knocking control apparatus according to claim 6, wherein one or both of the advance period of the ignition timing and the advance amount for each period are based on one or both of the rotational speed and the load of the internal combustion engine. An internal combustion engine knocking control device that is adjusted. 8. The internal combustion engine knocking control apparatus according to claim 7, wherein an advance period of the ignition timing is lengthened as the load on the internal combustion engine is higher. 9. The internal combustion engine knocking control apparatus according to claim 7, wherein the advance amount of the ignition timing for each cycle is reduced as the load on the internal combustion engine is higher. The internal combustion engine knocking control apparatus according to any one of claims 7 to 9, wherein the advance amount of the ignition timing for each cycle is reduced as the rotational speed of the internal combustion engine is reduced. apparatus. 11. The internal combustion engine knocking control apparatus according to claim 10, wherein the advance period of the ignition timing is shortened as the rotational speed of the internal combustion engine is smaller.

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