JPH08151950A - Knocking control device for internal combustion engine - Google Patents

Abstract

PURPOSE: To attain improving fuel consumption and output torque while suppressing the occurrence of knocking at transient operation time regardless of characteristic dispersion of an engine and a knocking sensor and aged deterioration thereof. CONSTITUTION: In an electronic control unit(ECU) 41, based on a value of processing a detection value averaged of a knocking sensor 36, a knocking decision level is calculated. In the ECU41, by comparing its decision level with the detection value of the knocking sensor 36, the occurrence of knocking is decided for whether it is provided or not. In the ECU41, when placing an engine 1 in a steady operation condition is judged, based on the detection value of the knocking sensor 36, a degree of the occurrence of knocking is calculated. In the ECU41, when the engine 1 is judged in a transient operation condition, in order to correct a delay of calculating the knocking decision level, a correction value is added/subtracted to/from this decision level, also to change a level of this correction value in accordance with a level of a calculated value in a degree of the occurrence of knocking.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knocking control device for controlling knocking generated in an internal combustion engine. More specifically, the present invention relates to a knocking control device for an internal combustion engine, which determines whether knocking has occurred by comparing a knocking determination level with a detection value of a knock sensor or the like, and controls the occurrence of knocking based on the determination result. .

[0002]

2. Description of the Related Art Conventionally, in an internal combustion engine, especially a gasoline engine, when the air-fuel mixture in the combustion chamber abnormally burns, the pressure in the combustion chamber rises much faster than it normally would. Therefore, knocking occurs repeatedly each time combustion occurs in the combustion chamber. Here, combustion under the condition of occurrence of slight knocking within the allowable range is preferable from the viewpoint of improving fuel efficiency and output torque of the engine. However, if the frequency or size of knocking exceeds the allowable range,
Not good for the engine.

Therefore, the occurrence frequency of knocking is detected by a knock sensor or the like, and the ignition timing is controlled by retarding or advancing the ignition timing based on the detected value to control the occurrence of knocking. There is something. Japanese Patent Laid-Open No. 210210/1990 discloses an example of a device related to the above control. That is, in this device, the control unit (computer) uses the time constant set according to the detected value of the crank angle sensor (engine speed) to smooth the knocked sensor values, that is, to average them. The noise level is calculated by Further, the computer calculates a knocking determination level which is a criterion for determining whether knocking has occurred, based on the calculated noise level. Then, the computer determines whether or not knocking has occurred by comparing the calculated knocking determination level with the detection value of the knock sensor. In this determination, since the detected value of the knock sensor is smoothed, it is possible to eliminate the influence of noise from the determination even if the detected value includes some noise.

However, in the conventional device, during transient operation of the engine, for example, during acceleration, the noise level calculation is delayed with respect to the increase in the signal output from the knock sensor, and thus the knocking determination level is delayed. As a result, the knocking determination level becomes unnecessarily low, and the computer erroneously determines that knocking has occurred.

Therefore, in order to prevent this erroneous determination, in the device of the above publication, the computer calculates a correction value according to the transient operating state of the engine during transient operation, and corrects the noise level based on the correction value. . Specifically, the computer calculates the amount of change in the throttle opening corresponding to the degree of acceleration based on the detection value of the throttle sensor. Then, the computer raises the knocking determination level by a predetermined value in accordance with the calculated value to calculate a knocking determination level different from that during steady operation. As a result, the computer corrects the shortage of the knocking determination level due to the delay in calculation of the noise level.

[0006]

However, in the apparatus disclosed in the above publication, the computer sets the same padding value for the same degree of acceleration. Therefore, even if there are variations in the characteristics of the engine, the knock sensor, etc., or their changes over time, these fluctuation factors cannot be reflected in the raised value. Therefore, it is not possible to calculate an optimal knocking determination level that takes these fluctuation factors into account. As a result, during transient operation of the engine, the computer may erroneously determine whether knocking has occurred. In other words, even if knocking that exceeds the allowable level has actually occurred, the computer cannot determine that, or even if knocking that exceeds the allowable level has not occurred, the computer There is a risk of determining the occurrence of knocking.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is the occurrence frequency and magnitude of knocking, regardless of variations in characteristics of the internal combustion engine, knock sensor, etc. and changes over time. A knocking control of the internal combustion engine that can maximize the fuel consumption and output torque of the internal combustion engine while minimizing the occurrence of knocking during transient operation by calculating the optimal knocking determination level according to To provide a device.

[0008]

In order to achieve the above object, in the present invention, as shown in FIG. 1, the magnitude of knocking generated in the internal combustion engine M1 is detected by knock detecting means M2, and A knocking control device configured to determine the presence or absence of knocking by comparing a detected value with a knocking determination level, and control the knocking adjustment means M3 based on the determination result to control the occurrence of knocking. , Knock detection means M2
Determination level calculating means M4 for calculating a knocking determination level based on a value obtained by smoothing the detected value of M, and the knocking determination level and knock detection means M2 calculated by the determination level calculating means M4.
Knocking determination means M5 for determining the presence or absence of knocking by comparing with the detection value of No., and knocking determination means M5 for controlling the occurrence of knocking.
Based on the detection value of the control means M6 for controlling the knocking adjustment means M3 based on the determination result, the operation state detection means M7 for detecting the operation state of the internal combustion engine M1, and the detection value of the operation state detection means M7, When the internal combustion engine M1 is in a transient operating state or in a steady operating state, an operating state determining means M8 and a determination result of the operating state determining means M8 is in a transient operating state Determination level calculating means M for correcting the calculation delay
When the determination result of the determination level correction means M9 for adding or subtracting the correction value to the knocking determination level calculated by 4 and the operation state determination means M8 is the steady operation state, knocking is performed based on the detection value of the knock detection means M2. And a correction value changing means M11 for changing the correction value in the determination level correcting means M9 based on the calculated value of the occurrence degree calculating means M10. The purpose is.

[0009]

The operation of the structure shown in FIG. 1 will be described. The knocking determination means M5 determines whether knocking has occurred by comparing the knocking determination level calculated by the smoothing processing by the determination level calculation means M4 with the actual magnitude of knocking detected by the knock detection means M2. To do. Then, the control unit M6 controls the knocking adjustment unit M3 based on the knocking determination result to control the occurrence of knocking in the internal combustion engine M1.

When the operating condition judging means M8 judges that the internal combustion engine M1 is in a steady operating condition, that is, a constant speed operating condition, the occurrence degree calculating means M10 calculates the degree of knocking occurrence. When the internal combustion engine M1 is in a transient operating state, that is, in an accelerating or decelerating state and the operating state determining means M8 determines it, the determination level correcting means M9 is in a transient operating state due to the smoothing process. In order to correct the calculation delay that occurs, a correction value is added to or subtracted from the knocking determination level calculated by the determination level calculating means M4.
Further, the correction value changing means M11 is provided with the occurrence degree calculating means M1.
The correction value in the determination level correction means M9 is changed based on the degree of knocking occurrence calculated at 0.

Therefore, during transient operation of the internal combustion engine M1,
Since the knocking determination level is corrected by adjusting the correction value, regardless of the calculation delay caused by the smoothing process,
The judgment level is optimized. Furthermore, the above correction values include
Since variation factors such as variations in the characteristics of the internal combustion engine M1 and the knock detection means M2 and their changes over time are reflected, the variation factors described above are also reflected in the knocking determination level corrected during transient operation. Become.

[0012]

【Example】

(First Embodiment) Hereinafter, a first embodiment in which a knocking control device for an internal combustion engine according to the present invention is embodied in an automobile will be described with reference to FIGS.
This will be described in detail with reference to FIG.

FIG. 2 is a schematic configuration diagram showing a gasoline engine system. A gasoline engine (hereinafter simply referred to as “engine”) 1 as an internal combustion engine includes a cylinder block 1a and a cylinder head 1b, and the cylinder block 1a includes a plurality of cylinders including a combustion chamber 1c. The outside air drawn from the air cleaner 3 into the intake passage 4 flows through the intake port 2 corresponding to each cylinder. The injector 5 provided for each cylinder injects fuel into each intake port 2. Then, the mixture of the outside air and the fuel is introduced into the combustion chamber 1c when the intake port 2 is opened by the intake valve 6 provided for each cylinder. Further, by operating the ignition plug 7 provided for each cylinder, the air-fuel mixture explodes and burns in the combustion chamber 1c, and the piston 8 operates,
The driving force of the engine 1 can be obtained. Then, when the exhaust port 10 is opened by the exhaust valve 9 provided for each cylinder, the burned gas is led out from the combustion chamber 1c to the exhaust passage 11 as exhaust gas, further purified by the catalyst 12 and discharged to the outside. To be done.

A throttle valve 13 provided in the middle of the intake passage 4 operates in conjunction with the operation of an accelerator pedal (not shown) to open and close the intake passage 4. The operation of the throttle valve 13 adjusts the intake air amount Q to the intake passage 4.

An intake air temperature sensor 31 provided in the vicinity of the air cleaner 3 detects the temperature (intake air temperature) THA of the air drawn into the intake passage 4 and outputs a signal corresponding to the temperature. The air flow meter 32 provided in the vicinity of the air cleaner 3 detects the intake air amount Q in the intake passage 4 and outputs a signal corresponding to the amount. A throttle sensor 33 provided in the vicinity of the throttle valve 13 detects the opening (throttle opening) TA of the valve 13 and outputs a signal corresponding to the opening. The sensor 33 also detects that the throttle valve 13 is fully closed.

On the other hand, the oxygen sensor 34 provided in the middle of the exhaust passage 11 detects the oxygen concentration Ox remaining in the exhaust gas and outputs a signal according to the concentration. The water temperature sensor 35 provided in the cylinder block 1a detects the temperature (cooling water temperature) THW of the cooling water flowing to cool the block 1a, and outputs a signal according to the temperature. Further, the knock sensor 36 provided in the cylinder block 1a as the knock detecting means in the present invention detects a vibration including knocking generated in the engine 1, and outputs a knock signal KCS according to the magnitude of the vibration.

The distributor 14 is for each spark plug 7
Distributes the ignition signal to be applied to. Igniter 15
Outputs a high voltage to the distributor 14 in synchronization with a change in the crank angle of the engine 1. The ignition timing of each spark plug 7 is determined by the high voltage output timing of the igniter 15. In this embodiment, each spark plug 7 and the igniter 15 constitute the knocking adjusting means in the present invention.

The rotation speed sensor 37 provided in the distributor 14 detects the rotation speed (engine rotation speed) NE of the engine 1 based on the rotation of a rotor (not shown) incorporated in the distributor 14 and responds to the detected speed. Output signal. Similarly distributor 1
The cylinder discrimination sensor 38 provided in No. 4 detects a change in the crank angle of the engine 1 at a predetermined rate based on the rotation of the rotor, and outputs a signal according to the change.

In this embodiment, various sensors and the like 3
1 to 38 constitute an operating state detecting means in the present invention for detecting the operating state of the engine 1. Here, the electronic control unit (ECU) 41 constitutes the judgment level calculation means, the knocking judgment means, the control means, the operating state judgment means, the judgment level correction means, the generation degree calculation means, and the correction value change means in the present invention. The ECU 41 inputs signals output from the various sensors 31 to 38 described above. E
The CU 41 controls each injector 5 and igniter 15 based on these input signals.

As shown in the block diagram of FIG. 3, the ECU 4
1 is a central processing unit (CPU) 42, a read only memory (ROM) 43, a random access memory (RAM) 4
4 and backup RAM 45 and timer counter 46
Etc. are provided. The ECU 41 constitutes a logical operation circuit in which these units 42 to 46, an external input circuit 47, an external output circuit 48 and the like are connected by a bus 49. Where R
The OM 43 stores a predetermined control program and the like in advance. R
The AM 44 temporarily stores the calculation result of the CPU 42 and the like. The backup RAM 45 stores previously stored data. The timer counter 46 can simultaneously perform a plurality of counting operations. The external input circuit 47 includes a buffer, a waveform shaping circuit, an A / D converter, and the like. External output circuit 4
Reference numeral 8 includes a drive circuit and the like. The various sensors 31 to 38 are connected to the external input circuit 47. Each member 5, 15 is connected to the external output circuit 48.

The CPU 42 reads the signals from the various sensors 31 to 38 input via the external input circuit 47 as input values. Based on these input values, the CPU 42 controls each member 5, 15 and the like in order to execute fuel injection amount control including air-fuel ratio control and ignition timing control including knocking control. A battery (not shown) mounted on the vehicle is connected to the ECU 41. The control of each member 5, 15 and the like performed by the CPU 42 includes controlling the energization of each member 5, 15 and the like from the battery.

Here, the fuel injection amount control means the engine 1
That is, the amount of fuel injected from each injector 5 is controlled according to the operating state. The air-fuel ratio control is to control the air-fuel ratio A / F in the engine 1 based on at least the detection value of the oxygen sensor 34. The ignition timing control is to control the igniter 15 according to the operating state of the engine 1 to operate each spark plug 7 and control the ignition timing of the air-fuel mixture in each combustion chamber 1c. Further, the knocking control is to control the occurrence of knocking by determining the presence or absence of knocking based on the detection value of the knock sensor 36 and controlling the ignition timing based on the determination result.

Next, of the various controls executed by the ECU 41 described above, the content of the knocking control process including the ignition timing control will be described with reference to the various flowcharts of FIGS. 4 to 10. The ROM 43 stores in advance control programs, function data, and the like relating to various routines described below.

FIG. 4 shows an "ignition timing control routine" for ignition timing control including knocking control.
Executes this routine periodically at predetermined time intervals. EC
When the U41 shifts to this routine, in step 100, the values of the intake air amount Q, the cooling water temperature THW and the engine rotation speed NE are read based on the detection signals of the sensors 32, 35, 37, respectively.

In step 110, the ECU 41 reads the intake air amount Q and the engine speed NE read this time.
A value of the basic ignition timing ITb corresponding to the values of the operating load Q / NE of the engine 1 and the engine rotation speed is calculated based on the value of.

In step 120, the ECU 41 determines whether or not the condition for executing knocking control is satisfied this time. Here, the ECU 41 determines that the execution condition is satisfied when the value of the cooling water temperature THW is equal to or higher than the predetermined value and the value of the operating load Q / NE is equal to or higher than the predetermined value. If the above execution conditions are not satisfied, EC
U41 shifts the processing to step 150 as it is. When the execution condition is satisfied, the ECU 41 shifts the processing to step 130.

In step 130, the ECU 41 reads from the RAM 44 the value of the knocking intensity KCM corresponding to the degree of knocking occurrence calculated according to the "knocking determination processing routine" shown in FIG. Next, at step 140, the ECU 41 calculates a knocking correction value KCC for retarding the ignition timing according to the read knocking intensity KCM, that is, according to the degree of knocking occurrence. In this embodiment, the above step 1
The ECU 41 that executes steps 30 and 140 corresponds to the knocking determination means in the present invention.

Then, in step 150 after shifting from steps 120 and 140, the ECU 41 calculates another correction value C1 for correcting the ignition timing according to factors other than the occurrence of knocking. As is well known, in the ignition timing control, the ignition timing is advanced or retarded according to the magnitude of the cooling water temperature THW, or the ignition timing is adjusted according to the deviation of the engine speed NE from the target value when the engine 1 is idling. To advance. In this step 150, EC
U41 calculates a correction value C1 required for such ignition timing control based on various parameters THW, NE and the like.

Then, in step 160, the ECU
41 calculates a target ignition timing TI that should be finally used for ignition timing control. That is, the ECU 41 calculates the target ignition timing IT by correcting the basic ignition timing TIb based on the various correction values KCC and C1.

Then, in step 170, the ECU
Reference numeral 41 controls the igniter 15 at a required timing based on the target ignition timing IT calculated this time to actually control the ignition timing of the air-fuel mixture in the combustion chamber 1c.
After that, the ECU 41 ends the process once, and restarts the process from step 100 at the next timing. In this embodiment, the ECU 41 that executes the processing of step 170
Corresponds to the control means in the present invention.

As described above, the ECU 41 controls the target ignition timing I
When T is calculated, the normal ignition timing control is executed based on the calculated result, and when the knocking control execution condition is satisfied, the ignition timing control for the knocking control is executed.

By the way, the ECU 41 uses the rotation speed sensor 3
The explosion stroke timing in each cylinder of the engine 1 is determined based on the detection signals of the cylinder 7 and the cylinder discrimination sensor 38. And
Each time the determination is made, the knocking determination process is started at the timing when the piston 8 reaches the top dead center in each cylinder. FIG. 5 shows a "knocking determination processing routine" for that purpose. EC
U41 starts this routine each time each cylinder enters the explosion stroke. The ECU 41 classifies the knocking intensity generated in the engine 1 into four categories of none, small, medium, and large, and temporarily stores the determination result in the RAM 44.

When the ECU 41 shifts to this routine,
In step 200, each sensor, etc. 32, 35, 3
The values of the intake air amount Q, the cooling water temperature THW, the knock signal KCS, and the engine speed NE are read based on the detection signals of Nos. 6 and 37, respectively.

In step 210, the ECU 41 determines whether or not the knocking control execution condition is satisfied this time. The content of the execution condition here is the same as that in step 120 of FIG. If the execution condition is not satisfied, the ECU 41 executes the process in step 27.
Move to 0. If the above execution conditions are met,
The ECU 41 shifts the processing to step 220.

At step 220, the ECU 41 calculates the knocking determination level VL. This judgment level V
L is the knocking strength KC of the cylinder in the explosion stroke this time.
It is a standard for determining M. ECU 41
Calculates the knocking determination level VL according to the following calculation formula (1).

VL = VM0 * (K + ΔK) + VOS (1) Here, “VM0” is the knock signal KC obtained when the knocking determination process was executed for the cylinder last time.
It is a smoothed value obtained by smoothing S, that is, averaging. “K” is a reference value set according to the engine rotation speed NE in order to calculate the knocking determination level VL. “ΔK” is a correction value that is learned and updated every predetermined period so that the knocking sound is constant, and this learning and updating will be described later. Furthermore, "VO
“S” is a padding value that is added to the knocking determination level VL in order to correct the knocking determination level VL during transient operation of the engine 1, and the knocking value of the engine 1 during steady operation (such as constant speed operation) It is calculated according to the degree of occurrence, that is, the ease with which knocking occurs. This raised value V
OS is a value calculated as a positive or negative value, and the calculation method will be described later. The ECU 41 calculates the various parameters VL, VM, ΔK, and VOS for each cylinder. Further, the ECU 41 sets the correction value ΔK to the low speed correction value ΔK according to the magnitude of the engine rotation speed NE.
L, medium speed correction value ΔKM, and high speed correction value ΔKH are set to three types. Then, when calculating the knocking determination level VL, the ECU 41 calculates three types of correction values ΔKL,
The one corresponding to the engine speed NE is selected from ΔKM and ΔKH and used. In this embodiment, the ECU 41 that executes the processing of step 220 corresponds to the determination level calculating means in the present invention.

Next, at step 230, the ECU 4
1 determines the knocking strength KCM based on the knock signal KCS read this time and the knocking determination level VL calculated this time, and calculates the maximum value VP of the knock signal KCS within this determination section. The details of this step 230 will be described later with reference to FIG. In this embodiment, the ECU 41 that executes the processing of step 230 constitutes the knocking determination means of the present invention.

In step 240, the ECU 41 determines the determined knocking strength KCM and the calculated maximum value V.
Each P is temporarily stored in the RAM 44. Then, in step 250, the ECU 41 determines whether or not a condition for correcting the knocking determination level VL is satisfied. The correction condition here means a case where both the steady operation state of the engine 1 and the fact that the engine rotation speed NE is within a predetermined range are compatible. When the correction condition is satisfied, the ECU 41 shifts the processing to step 260. If the correction condition is not satisfied, the ECU
41 shifts the processing to step 270. In this embodiment, the ECU 41 that executes the processing of step 250
, Which constitutes the operating condition determining means in the present invention.

At step 260, the ECU 41 determines the knocking determination level V so that the knocking sound becomes constant.
A process of learning and updating the correction value ΔK for correcting L is executed, and the subsequent process is temporarily terminated. The details of step 260 will be described later with reference to FIGS. In this embodiment, the ECU 41 that executes the processing of step 260 corresponds to the occurrence degree calculating means in the present invention.

On the other hand, after shifting from steps 210 and 250, in step 270, the ECU 41 initializes various counters and the like used when the learning update of the correction value ΔK is executed, and thereafter ends the processing once.

FIG. 6 shows a "maximum value calculation routine" for calculating the maximum value VP in step 230.
First, in step 300, the ECU 41 sets the start time tS and the end time tE based on the engine rotation speed NE. Here, "10 ° CA / ATDC to 90 ° CA / ATD for each cylinder in the explosion stroke this time"
The section “C” is set as the knocking determination section, and the start time tS and the end time tE of the determination section from the present time are set to the ECU 41.
Set. Further, the ECU 41 determines that the times tS, t
Set a timer to time E.

Next, at step 310, the ECU 4
1 waits for the knocking determination to start. That is, the ECU
Reference numeral 41 waits until the time measurement result of the timer reaches the start time tS. When the start time tS is reached, step 32
At 0, the ECU 41 reads the A / D converted value (hereinafter referred to as “knock signal level”) VAD of the knock signal KCS.

Then, in step 330, the ECU
Reference numeral 41 compares the value of the knocking determination level VL calculated in step 220 of FIG. 5 with the value of the knock signal level VAD. If knock signal level VAD is higher than knocking determination level VL, ECU 41 determines that knocking has occurred in engine 1, and ECU 41 shifts the processing to step 340. And step 340
At 41, the ECU 41 increments the value of the first counter Cx for knocking determination by “1”, and proceeds to step 350. That is, the ECU 41 increments the number of times the knock signal level VAD exceeds the knocking determination level VL. Knock signal level VAD
Is below the knocking determination level VL, EC
U41 shifts the processing to step 350 as it is.

In step 350, the ECU 41 calculates the average value VMAD of the knock signal KCS by the following formula (2).
Calculate according to. VMAD = (15 * VMAD0 + VAD) / 16 (2) Here, VMAD0 is the value of the average value VMAD calculated last time.

Further, in step 360, the ECU 4
1 determines whether the value of the knock signal level VAD exceeds the maximum value VP. If the value of the knock signal level VAD exceeds the maximum value VP, in step 370, E
The CU 41 sets the knock signal level VAD at that time as the maximum value VP, and then shifts the processing to step 380. That is, the ECU 41 updates the maximum value VP. If the value of the knock signal level VAD is less than the maximum value VP, the ECU 41 directly proceeds to step 38.
Move to 0.

At step 380, the ECU 41 determines whether or not the knocking determination is to be ended. That is, EC
U41 determines whether or not the timing result of the timer set in step 300 has reached the end time tE. If the time measurement result has not reached the end time tE, the ECU
41 shifts the processing to step 320, and step 320
The processes of ˜370 are executed again. Time measurement result is the end time t
If E is reached, the ECU 41 proceeds to step 39.
Move to 0.

In step 390, the ECU 41 calculates the smoothed value VM of the knock signal KCS used for calculating the knocking determination level VL in the next processing according to the following calculation formula (3).

VM = (3 * VM0 + VMAD) / 4 (3) Here, VM0 is the previous smoothed value that was already used to calculate the knocking determination level VL in step 220 described above.

In step 400, the ECU 41 determines the knocking strength KCM according to the value of the counter Cx incremented in step 340 in the knocking determination section from the start time tS to the end time tE. Here, the ECU 41 determines that the value of the counter Cx is “1.
If it is "or less", it is determined that there is no knocking,
If the same value is "2 to 5", knocking strength KCM
Is determined to be small. Further, the ECU 41 determines that the knocking strength KCM is medium when the same value is “6 to 9”, and determines that the knocking strength KCM is large when the same value is “10 or more”. . Then, in step 410, the ECU 41 initializes the value of the first counter Cx to “0”.

Further, in step 420, the ECU 4
1 indicates whether knocking has occurred, that is, step 400
The determination result of the knocking strength KCM in "is large / medium /
It is determined whether or not it is "small". Then, if knocking has occurred, it is determined that the ignition timing retard control by the knocking control is executed, and step 43
At 0, the ECU 41 sets the second counter CK to "1".
Only, and the subsequent processing is once ended.
If knocking has not occurred, it is assumed that the ignition timing retard control by knocking control is not executed, and the subsequent processing is temporarily terminated.

7 and 8 show a "correction value learning update routine" executed to learn and update the correction value ΔK in step 260. First, in step 500,
The ECU 41 increments the value of the third counter CP for counting the number of executions of this routine for each cylinder by "1".

Next, at step 510, it is judged if the maximum value VP of the knock signal KCS calculated this time is larger than the median value V50 calculated for each cylinder. This median value V50 is a value corresponding to the 50% point in the frequency distribution of the maximum value VP. Here, when the maximum value VP is larger than the median value V50, the ECU 41 shifts the processing to step 520, and the maximum value VP is the median value V50.
If less, the ECU 41 proceeds to step 54
Move to 0.

In step 520, the ECU 41 updates the median value V50 by adding a predetermined set value ΔV50 described later to the median value V50, and then shifts the processing to step 530.

On the other hand, in step 540, the ECU 4
1 determines whether the maximum value VP is smaller than the calculated median value V50. When the maximum value VP is smaller than the median value V50, the ECU 41 updates the median value V50 by subtracting the set value ΔV50 from the median value V50 in step 550, and shifts the processing to step 530. If the maximum value VP is not smaller than the median value V50, the ECU 41 proceeds with the process to step 530.

In step 530, the ECU 41 calculates the set value Δ50 to be used next time to update the median value V50 according to the following calculation formula (4). ΔV50 = | VP−V50 | / 16 (4) In steps 510 to 550, when the maximum value VP is larger than the median value V50, the median value V50 is the set value Δ.
When the maximum value VP is increased by V50 and is smaller than the median value V50, the median value V50 is decreased by the set value ΔV50. As a result, the median value V50 is always 50% of the cumulative value of the maximum value VP.

Next, in step 560, the ECU 4
1 calculates a target coefficient D for knocking sound adjustment based on the value of the engine speed NE. Further, step 570
In the above, the ECU 41 calculates the upper limit value VH and the lower limit value VL of the maximum value VP for each cylinder by the following formula (5),
Calculate according to (6).

VH = (A + D) * V50 (5) VL = V50 / A (6) Here, "A" is a variable used to set the upper limit value VH and the lower limit value VL. The ECU 41 updates the variable A every predetermined time by the process described later.

Then, in step 580, the ECU
41 determines whether the maximum value VP has fallen below the lower limit value VL. Then, the ECU 41 determines that the maximum value VP is the lower limit value VL.
If it is less than, the process proceeds to step 590,
If the maximum value VP is not below the lower limit value VL, the process proceeds to step 620.

In step 590, the ECU 41 decrements the value of the fourth counter CHL set for each cylinder by "1" for determining the distribution shape of the logarithmic change value of the maximum value VP. Further, in step 600, the EC
U41 is a fifth counter C set for each cylinder in order to count the number of times that the maximum value VP falls below the lower limit value VL.
The value of L is incremented by "1", and the process proceeds to step 610.

On the other hand, in step 620, the ECU 41
Determines whether the maximum value VP exceeds the upper limit value VH.
If the maximum value VP exceeds the upper limit value VH, the ECU 41 determines in step 630 that the counter C
The value of HL is incremented by "1", and the process proceeds to step 610. If the maximum value VP does not exceed the upper limit value VH, the ECU 41 proceeds with the process to step 610.

In step 610, the ECU 41 initializes the maximum value VP to "0" in order to calculate a new maximum value VP in the next knocking determination section. Then, in step 615, the ECU 41 learns and updates the correction value ΔK the previous time, and then the ECU 41 receives a predetermined time (eg, “0.7
Seconds ”) has elapsed. If the predetermined time has not elapsed, the ECU 41 once ends the subsequent processing. If the specified time has passed, EC
U41 transfers the processing to step 640.

At step 640, the ECU 41 determines whether or not the value of the third counter CP incremented at step 500 is greater than a predetermined value (for example, "16") within the elapsed time. Here, if the number of times that the ECU 41 executes the above steps 500 to 630 is small during the elapse of the predetermined time, the distribution shape of the logarithmic change value of the maximum value VP should be accurately determined based on the value of the fourth counter CHL. I can't. As a result, there is a risk that the correction value ΔK will be learned and updated to an erroneous value in the processing of step 650 and subsequent steps. Step 640 is a process for prohibiting the learning update of the correction value ΔK in such a case. Therefore,
When the value of the third counter CP is less than the predetermined value in this step 640, the ECU 41 directly shifts the processing to step 740. On the other hand, if the value of the third counter CP is larger than the predetermined value in step 640, EC
U41 shifts the processing to step 650.

In step 650, the ECU 41 determines whether or not the value of the fourth counter CHL is a positive value. Here, when the value of the fourth counter CHL is a positive value (that is, when the number of times the maximum value VP exceeds the upper limit value VH is greater than the number of times the lower limit value VL is below), knocking occurs. If the frequency is higher than the target value, E
The CU 41 shifts the processing to step 660.

In step 660, the ECU 41 determines whether or not the value of the second counter CK is "1" or less. Here, when the value of the second counter CK is equal to or less than “1”, in step 670, the ECU 41 subtracts the predetermined value β from the correction value ΔK to obtain the correction value Δ.
Update K. After that, the ECU 41 proceeds to step 6
Move to 80. When the value of the second counter CK is smaller than “1”, the ECU 41 directly shifts the processing to step 680.

In other words, although the frequency of knocking is higher than the target value, the value of the second counter CK is "1" or less and the ignition timing retard control by the knocking control is performed during a predetermined time. When the number of times of execution is one or less, the ECU 41 decreases the correction value ΔK, assuming that the knock determination level VL is excessively large.

On the other hand, in step 650, when the value of the fourth counter CHL is not a positive value, step 6
At 90, the ECU 41 determines whether or not the value of the fourth counter CHL is a negative value. Then, when the value of the fourth counter CHL is not a negative value, the ECU 41 directly shifts the processing to step 680. When the value of the fourth counter CHL is a negative value (that is, the maximum value VP
Is lower than the lower limit value VL and is higher than the upper limit value VH), it is determined that the knocking occurrence frequency is lower than the target value, and the ECU 41 shifts the processing to step 700.

At step 700, the ECU 41 determines whether or not the value of the second counter CK exceeds "1". Here, when the value of the second counter CK exceeds “1”, in step 710, the ECU 41 updates the correction value ΔK by adding the predetermined value β to the correction value ΔK. After that, the ECU 41 shifts the processing to step 680. If the value of the second counter CK is less than “1”, the ECU 41 directly proceeds to step 680.
Move to.

That is, although the frequency of knocking is lower than the target value, the ignition timing retard control by knocking control is performed while the value of the second counter CK exceeds "1" and a predetermined time elapses. When it is executed a plurality of times, the ECU 41 increases the correction value ΔK, assuming that the knocking determination level V is too low.

The routine of steps 650 to 710 is to successively update the correction value ΔK used for calculating the knocking determination level VL so that the distribution shape of the maximum value VP becomes a desired shape. This is for correcting the determination level VL so that the knocking sound becomes constant.

Further, in this embodiment, the ECU 41 determines that the correction value Δ
K is set to three types of correction values ΔKL, ΔKM, and ΔKH for low speed, medium speed, and high speed according to the engine rotation speed NE. Therefore, in step 670 or step 710, when updating the correction value ΔK, the ECU 41 selects the correction value ΔK according to the engine rotation speed NE from the three types of correction values ΔKL, ΔKM, ΔKH and updates the value. To do.

Then, in step 680, the ECU
Step 41 determines whether or not the value of the fifth counter CL incremented when the maximum value VP falls below the lower limit value VL in step 600 is "0". If the value of the fifth counter CL is "0", the ECU 41 subtracts the predetermined value γ from the variable A used to set the upper limit value VH in step 720.
Is updated, and the process proceeds to step 740. If the value of the fifth counter CL is not “0”, step 73
At 0, the ECU 41 updates the variable A by adding a predetermined value γ to the variable A, and the process proceeds to step 740.
Move to.

By this processing, the value of the variable A is the maximum value VP.
Is sequentially updated so that the number of times that is lower than the lower limit value VL is “1” or less. Then, in step 740, the EC
U41 performs the above step 650 after the predetermined time has elapsed.
In order to make it possible to update the correction value ΔK in ~ 730,
Various counters CP, CHL, used for updating
The values of CL and CK are initialized to "0". As described above, the correction value ΔK (ΔKL, ΔKM, ΔKH) used to correct the knocking determination level VL is learned and updated when the engine 1 is in steady operation. In this example,
Deviation between the number of times the maximum value VP exceeds the upper limit value VH and the number of times it falls below the lower limit value VL (that is, the value of the fourth counter CHL)
Based on the above, the correction value ΔK is updated every predetermined time so that the distribution shape of the logarithmic conversion value of the maximum value VP becomes a predetermined shape. Then, the correction value ΔK learned and updated in this manner reflects a variation factor such as a variation in the characteristics of the engine 1 and the knock sensor 36, its variation with time, and the like.

FIG. 9 shows a "pad-up flag setting routine" for setting a flag for permitting or prohibiting the above-mentioned pad-up value VOS to be calculated. The ECU 41 executes this routine every predetermined time.

When the ECU 41 starts this routine,
In step 800, the values of various parameters THW and NE are read based on the detection signals of the various sensors 35 and 37, respectively. At the same time, the ECU 41 reads the execution flag XKF for fail safe. The ECU 41 sets the execution flag XKF according to a separate processing routine (not shown). That is, the ECU 41 determines that the execution flag XKF
Is set to "1" when the knock sensor 36 has a failure,
Set to "0" when there is no failure.

Next, at step 810, the ECU 4
1 calculates the value of the change value DNE between the previous value and the current value of the engine speed NE. Then, in step 815, the ECU 41 determines whether or not the absolute value of the change value DNE is larger than a predetermined reference value N1, that is, whether or not the engine 1 is in a transient operation state. And
When the absolute value of the change value DNE is less than the reference value N1, it is determined that the engine 1 is not in the transient operation state, and E
The CU 41 shifts the processing to step 870. Change value D
When the absolute value of NE is larger than the reference value N1, it is determined that the engine 1 is in the transient operation state, and the ECU 41 shifts the processing to step 820. In this embodiment, the ECU 41 that executes the processing of steps 810 and 815 described above.
, Which constitutes the operating condition determining means in the present invention.

In step 820, the ECU 41 determines that the value of the cooling water temperature THW is a predetermined reference value (eg, "60 ° C").
It is determined whether or not it is larger than that, that is, whether or not the engine 1 is in a warm-up state. Then, if the value of the cooling water temperature THW is less than the reference value, it is determined that the engine 1 is not in the warm-up state, and the ECU 41 shifts the processing to step 870. When the value of the cooling water temperature THW is larger than the reference value, it is determined that the engine 1 is warmed up, and the ECU 4
1 shifts the processing to step 830.

At step 830, the ECU 41 determines whether or not the execution flag XKF this time is "0". When the flag XKF is "1", that is, when the knock sensor 36 has a failure or the like, the ECU 41
Shifts the processing to step 870. Execution flag XKF
Is 0, that is, when the knock sensor 36 has no failure or the like, the ECU 41 shifts the processing to step 840.

At step 840, the ECU 41 increments the sixth counter CKC by "1" and shifts the processing to step 850. On the other hand, step 81
In step 870 after shifting from 5, 820 and 830, the ECU 41 initializes the counter CKC to “0”, and shifts the processing to step 880.

That is, when all the conditions relating to the above steps 815 to 830 are satisfied, the ECU 41 determines that the sixth
If the counter CKC is incremented and all the conditions are not satisfied, the ECU 41 determines that the counter CKC
Initialize C.

In step 850, the ECU 41 determines whether or not the value of the sixth counter CKC is greater than or equal to a predetermined reference value T1 (eg "48 ms"). And
When the value of the sixth counter CKC is smaller than the reference value T1, the ECU 41 shifts the processing to step 880. When the value of the sixth counter CKC is greater than or equal to the reference value T1, it is determined whether all the conditions relating to steps 815 to 830 are satisfied and the reference value T1 has elapsed. Then, when the value of the sixth counter CKC is equal to or greater than the reference value T1, in step 860, the ECU 4
In the case of 1, the padding flag XKC is set to "1" to allow the padding value VOS to be calculated and stored in the RAM 44, and the subsequent processing is temporarily terminated. When the value of the sixth counter CKC is smaller than the reference value T1, the ECU 41 shifts the processing to step 880.

In step 880 after shifting from steps 870 and 850, the ECU 41 sets the padding flag XKC to "0" and stores it in the RAM 44 in order to prohibit the calculation of the padding value VOS, and thereafter ends the processing once. To do.

Therefore, according to this routine, the ECU is executed only when the engine 1 is in the transient operation, after the engine 1 has been warmed up, and when the knock sensor 36 has no failure.
Reference numeral 41 sets the padding flag XKC to "1" in order to allow the padding value VOS to be calculated.

FIG. 10 shows a "padding value calculation routine" executed by using the padding flag XKC. ECU
41 executes this routine every predetermined time. ECU4
When the routine 1 starts this routine, in step 900, the value of the set padding flag XKC is read from the RAM 44. Then, in step 905, the ECU
41 determines whether or not the padding flag XKC is "1".

At step 905, the padding flag X is set.
When KC is “0”, that is, when the calculation of the padding value VOS is prohibited, the ECU 41 shifts the processing to step 990. In step 990, the ECU 4
1 sets the padding value VOS to "0" and sets the value in RAM
After storing in 44, the subsequent processing is once ended.

On the other hand, in step 905, when the padding flag XKC is "1", that is, when the padding value VOS is permitted to be calculated, the ECU 41 shifts the processing to step 910. Then, in step 910, the ECU 41 uses the RAM 44 to store the various correction values ΔKL, ΔKM, and ΔKH that have already been learned and updated in the routines of FIGS.
Read from each.

Subsequently, in step 920, the ECU
Reference numeral 41 determines whether or not the correction value ΔKL for low speed is larger than the reference value Kp. Here, the correction value ΔKL is the reference value Kp
If less, the ECU 41 proceeds to step 95.
Move to 0. When the correction value ΔKL is larger than the reference value Kp, the ECU 41 shifts the processing to step 930.

In step 930, the ECU 41 determines whether or not the medium speed correction value ΔKM is larger than the reference value Kp. Here, when the correction value ΔKM is less than the reference value Kp, the ECU 41 shifts the processing to step 945. When the correction value ΔKM is larger than the reference value Kp, the ECU 41 shifts the processing to step 935.

At step 935, the ECU 41 determines whether or not the correction value ΔKH for high speed is larger than the reference value Kp. Here, when the correction value ΔKH is less than the reference value Kp, the ECU 41 shifts the processing to step 945. When the correction value ΔKM is larger than the reference value Kp, that is, when all the correction values ΔKL, ΔKM, and ΔKH are larger than the reference value Kp, the degree of knocking occurrence in the engine 1 is large, and the ECU 41 executes the process. 94
Move to 0.

Then, in step 940, the ECU
Reference numeral 41 calculates the padding value VOS by adding the predetermined value VOSp to the predetermined padding reference value VOSb, and stores the calculation result in the RAM 44. That is, this step 94
At 0, the ECU 41 increases the padding value VOS. After that, the ECU 41 once ends the process.

At step 945 after shifting from steps 930 and 935, the ECU 41 determines the padding reference value VOS.
b is set as the raised value VOS as it is, and the value is set to R
Store in AM44. After that, the ECU 41 once ends the process.

On the other hand, steps 920 to 950
When the process shifts to, the ECU 41 executes steps 950-9.
The judgment of 70 is executed. That is, each step 950-97
At 0, the ECU 41 determines that the correction values ΔKL, ΔKM, Δ
It is determined whether or not each KH is smaller than a predetermined reference value Km (≠ Kp).

Then, in all steps 950 to 970, the correction values ΔKL, ΔKM, and ΔKH are set to the reference value Km.
If it is smaller than the above, the degree of occurrence of knocking in the engine 1 is small, so the ECU 41 shifts the processing to step 980. Then, in step 980,
The ECU 41 uses a predetermined reference value VOSb for raising the predetermined value V
Calculate the padding value VOS by subtracting OSm,
The calculation result is stored in the RAM 44. That is, in this step 980, the ECU 41 decreases the padding value VOS. After that, the ECU 41 once ends the process.

In each of steps 950 to 970, when the correction values ΔKL, ΔKM, ΔKH are equal to or larger than the reference value Km, the ECU 41 sets the raised reference value VOSb as the raised value VOS and stores the value in the RAM 44. To do. After that, the ECU 41 once ends the process.

Therefore, the ECU 41 executes the above routine to obtain the padding value VOS corresponding to the various correction values ΔKL, ΔKM, ΔKH calculated during the steady operation of the engine 1. This raised value VOS is obtained as a positive or negative value. Then, the ECU 41 uses this raised value VOS to correct the knocking determination level VL in the "knock determination processing routine" of FIG. In this embodiment, the ECU 41 that executes the above-mentioned "paddling value calculation routine" corresponds to the correction value changing means in the present invention.

As described above, according to the knocking control device of this embodiment, the ECU 41 controls the knock sensor 36.
The A / D-converted value of the knock signal KCS detected in step 1, that is, the knock signal level VAD is smoothed (averaged) to calculate the smoothed value VM. The ECU 41 indicates that the operating state of the engine 1 is a steady operating state (such as a constant speed operating state)
When it is determined that, the correction value ΔK used for keeping the knocking sound constant is learned and updated. The correction value ΔK reflects the degree of knocking occurrence. Further, the ECU 41 calculates the knocking determination level VL based on the smoothed value VM and the correction value ΔK. ECU 41
Is the knocking determination level VL and the knock signal level V
The presence or absence of knocking, that is, the knocking strength KCM is determined by comparing with AD. ECU 41
Calculates a correction value KCC for knocking control based on the knocking strength KCM, and calculates a target ignition timing IT based on the correction value KCC. The ECU 41 retards the ignition timing by controlling the igniter 15 at a required timing based on the target ignition timing IT, and controls the occurrence of knocking. In that sense, the fuel consumption and output torque of the engine 1 can be maximized while minimizing the frequency and magnitude of knocking.

In this embodiment, the knock signal level VAD
Therefore, even if the knock signal KCS contains some noise, the influence of the noise can be excluded from the determination of the knocking intensity KCM. This advantage is particularly effective during steady operation of the engine 1.

However, the knock signal level VAD is smoothed by determining the knocking determination level VL and the like when the engine 1 is in transient operation, that is, during acceleration operation or deceleration operation. May cause delays.

Therefore, in this embodiment, the delay in calculation of the knocking determination level VL and the like caused by the above-described smoothing processing is corrected. That is, when the ECU 41 determines that the engine 1 is in the transient operation state, the ECU 41 determines the knocking determination level VL.
Is added to the required amount of padding value VOS. Moreover, the ECU
Reference numeral 41 changes the magnitude of the padding value VOS based on the correction value ΔK which is learned and updated during the steady operation of the engine 1 and reflects the degree of knocking occurrence. This raised value VOS
In this case, variation factors such as variations in the characteristics of the engine 1 and the knock sensor 36 and changes with time thereof are reflected. Therefore, the above-described variation factor is also reflected in the knocking determination level VL corrected during the transient operation.

Therefore, in this embodiment, since the excess or deficiency related to the knocking determination level VL is corrected by the padding value VOS during the transient operation of the engine 1, the calculation delay due to the moderation process of the knock signal level VAD is concerned. No
The determination level VL is properly obtained. Further, since the padding value VOS is changed by reflecting the variation factors such as the engine 1 and the knock sensor 36, the difference in the variation factors is properly reflected in the knocking determination level VL during the transient operation. . As a result, even during transient operation of the engine 1, it is possible to maximize the fuel consumption and output torque of the engine 1 while minimizing the frequency and magnitude of knocking. It can be achieved regardless of variation factors such as variations in characteristics and changes over time.

Particularly, in this embodiment, the correction value ΔK learned and updated during the steady operation is set to the engine 1 and the knock sensor 3.
It is used as a parameter indicating the ease of occurrence of knocking reflecting factors such as 6. Therefore, as compared with the case where similar parameters are obtained and used during transient operation, in this embodiment, variations in the characteristics of the engine 1, the knock sensor 36, and the like and their changes over time are increased.
S, and by extension, can be reflected appropriately on the knocking determination level VL. In that sense, the knocking control during the transient operation can be optimized.

Further, in this embodiment, the knocking determination level VL used for knocking control is corrected by the correction value ΔK not only during transient operation of the engine 1 but also during steady operation. Therefore, the knocking determination level VL
Can be set according to the target knocking occurrence frequency. As a result, the knocking control can always be stably executed regardless of variations in the characteristics of the engine 1, the knock sensor 36, and the like and changes over time.

Further, in this embodiment, the variable A used for setting the upper limit value VH and the lower limit value VL is the predetermined number of times (in the present embodiment, the maximum value VP falls below the lower limit value VL) within a predetermined time. It is updated every predetermined time so that it becomes "1" or less). Further, the coefficient D for adjusting the target knocking sound for setting the upper limit value VH is the engine speed N
The higher E is, the smaller the value is set. Therefore, the correction value ΔK, and further the knocking determination level VL, are set to be smaller as the engine speed NE becomes higher, and the knocking sound felt by a human is changed to the engine speed NE.
It is possible to control it constantly regardless of the size of the.

(Second Embodiment) Next, a second embodiment in which the knocking control device for an internal combustion engine according to the present invention is embodied in an automobile.
An embodiment will be described with reference to FIGS. In this embodiment, the same components as those in the first embodiment will be designated by the same reference numerals and the description thereof will be omitted. Differences will be mainly described.

In this embodiment, the "padding value calculation routine"
The processing contents of No. 1 are different from those of the first embodiment, and the other points are the same. 11 and 12 show a "paddling value calculation routine" in this embodiment, and the ECU 41 executes this routine at predetermined time intervals.

When the ECU 41 starts this routine,
In step 1000, the set padding flag X has been set.
The value of KC is read from the RAM 44. Next, at step 1010, the ECU 41 sets the padding flag XK.
It is determined whether C is "1".

At step 1010, if the padding flag XKC is "0", that is, if the padding value VOS is prohibited from being calculated, the ECU 41 shifts the processing to step 1300. Then, in step 1300, the ECU 41 sets the padding value VOS to "0", stores the value in the RAM 44, and then temporarily terminates the subsequent processing.

On the other hand, in step 1010, when the padding flag XKC is "1", that is, the padding value VOS.
If the calculation of is allowed, the ECU 41 shifts the processing to step 1020. And step 102
At 0, the ECU 41 RAMs the various correction values ΔKL, ΔKM, ΔK that have already been learned and updated in the routines of FIGS.
Each is read from 44.

Subsequently, in step 1030, the EC
In U41, the correction value ΔKL for low speed is the correction value ΔKM for medium speed.
Is greater than or equal to. If the correction value ΔKL is less than the correction value ΔKM, the ECU 41 shifts the processing to step 1040. If the correction value ΔKL is larger than the correction value ΔKM, the ECU 41 executes the process in step 10.
Move to 50.

In step 1040, the ECU 41 determines whether or not the medium speed correction value ΔKM is larger than the high speed correction value ΔKH. If the correction value ΔKM is larger than the correction value ΔKH, the ECU 41 determines in step 1080 that the correction value ΔKM for medium speed is the maximum correction value ΔKmax.
Then, the process proceeds to step 1090. If the correction value ΔKM is less than the correction value ΔKH, the ECU
41 shifts the processing to step 1070.

On the other hand, in step 1050, the ECU
Reference numeral 41 determines whether or not the correction value ΔKL for low speed is larger than the correction value ΔKH for high speed. The correction value ΔKL is the correction value Δ
If it is larger than KH, the ECU 41 executes step 10
At 60, the correction value ΔKL for low speed is set to the maximum correction value ΔK.
It is set as max, and the process proceeds to step 1090. If the correction value ΔKM is less than the correction value ΔKH,
The ECU 41 shifts the processing to step 1070. In step 1070 after shifting from step 1050 or step 1040, the ECU 41 controls the correction value ΔK for high speed.
H is set as the maximum correction value ΔKmax, and the process proceeds to step 1090.

That is, in the routine of steps 1030 to 1080, the largest value among the various correction values ΔKL, ΔKM, and ΔKH is set as the maximum correction value ΔKmax.

In step 1090, the ECU 41 determines whether the correction value ΔKL for low speed is smaller than the correction value ΔKM for medium speed. If the correction value ΔKL is greater than or equal to the correction value ΔKM, the ECU 41 proceeds to step 110.
Move to 0. When the correction value ΔKL is smaller than the correction value ΔKM, the ECU 41 shifts the processing to step 1110.

In step 1100, the ECU 41 determines whether or not the medium speed correction value ΔKM is smaller than the high speed correction value ΔKH. When the correction value ΔKM is smaller than the correction value ΔKH, the ECU 41 determines in step 1140 that the correction value ΔKM for the medium speed is the minimum correction value ΔKmin.
Then, the process proceeds to step 1150. If the correction value ΔKM is greater than or equal to the correction value ΔKH, the ECU
41 shifts the processing to step 1130.

On the other hand, in step 1110, the ECU
Reference numeral 41 determines whether or not the correction value ΔKL for low speed is smaller than the correction value ΔKH for high speed. The correction value ΔKL is the correction value Δ
If it is smaller than KH, the ECU 41 executes step 11
20, the correction value ΔKL for low speed is set to the minimum correction value ΔK.
It is set as min, and the process proceeds to step 1150. When the correction value ΔKM is greater than or equal to the correction value ΔKH,
The ECU 41 shifts the processing to step 1130. In step 1130 after shifting from step 1110 or step 1100, the ECU 41 determines the correction value ΔK for high speed.
H is set as the minimum correction value ΔKmin, and the process proceeds to step 1150.

That is, in the routine of steps 1090 to 1140, the smallest value among the various correction values ΔKL, ΔKM and ΔKH is set as the minimum correction value ΔKmin.

Then, in step 1150, the EC
U41 determines whether or not the maximum correction value ΔKmax set this time is a negative value. When the maximum correction value ΔKmax is a negative value, the correction values ΔKL, ΔKM, and ΔKH are all negative values, so it is necessary to correct the padding value VOS to a small value. So, in this case, step 1
In 160, the ECU 41 sets the predetermined correction value VOSm used for calculating the padding value VOS to the maximum correction value ΔKm.
It is calculated based on ax. The ROM 43 stores in advance the function data relating to the predetermined negative value VOSm corresponding to the negative maximum correction value ΔKmax. Figure 1 shows the function data
3 shows. The ECU 41 calculates the predetermined value VOSm by using this function data.

Then, in step 1170, the EC
U41 calculates the padding value VOS by adding a predetermined negative value VOSm to the padding reference value VOSb, and stores the calculation result in the RAM 44. That is, in this step 1170, the ECU 41 decreases the padding value VOS. After that, the ECU 41 once ends the process.

On the other hand, when the maximum correction value ΔKmax is not a negative value in step 1150, the ECU 41 shifts the processing to step 1180. Step 1180
In, the ECU 41 determines that the minimum correction value ΔK set this time
It is determined whether min is a positive value. Here, when the minimum correction value ΔKmin is a positive value, each correction value ΔK
Since L, ΔKM, and ΔKH are all positive values, it is necessary to largely correct the padding value VOS. Therefore, in this case, in step 1190, the ECU 41 determines the predetermined value VOS used to calculate the padding value VOS.
p is calculated based on the minimum correction value ΔKmin. ROM
Reference numeral 43 stores in advance the function data relating to the predetermined positive value VOSp corresponding to the positive minimum correction value ΔKmin.
The function data is shown in FIG. The ECU 41 calculates the predetermined value VOSp by using this function data.

Then, in step 1200, the EC
The U41 calculates the padding value VOS by adding the positive padding value VOSp to the padding reference value VOSb, and stores the calculation result in the RAM 44. That is, in this step 1200, the ECU 41 increases the padding value VOS. After that, the ECU 41 once ends the process.

On the other hand, when the minimum correction value ΔKmin is not a positive value in step 1180, the ECU 41 shifts the processing to step 1210. Then, in step 1210, the ECU 41 determines that the predetermined padding reference value V
RAM is set as OSb as the raised value VOS
The data is stored in 44, and the subsequent processing is once ended.

That is, in this embodiment, the ECU 41 changes the padding value VOS according to the magnitude of the correction value ΔK (ΔKL, ΔKM, ΔKH), which is a predetermined value VOS.
m and VOSp are changed according to the degree of fluctuation of the correction values ΔKL, ΔKM, and ΔKH according to the magnitude of the engine speed NE.

Therefore, according to this embodiment, the engine 1
At the time of driving, the padding value VOS corresponding to the region of the engine rotation speed NE where knocking is likely to occur, that is, the low speed region, the medium speed region, or the high speed region is obtained. Then, during the transient operation of the engine 1, the knocking determination level VL is corrected based on the raised value VOS. As a result, during transient operation of the engine 1, the engine speed NE at that time is
According to the characteristics of the engine 1, the knock sensor 36, etc., the fuel consumption and the output torque of the engine 1 can be maximized while minimizing the frequency and magnitude of knocking. Can be achieved regardless of fluctuation factors such as the variation of the above and its change with time.

The present invention can be embodied in the following other embodiments. Also in the following other embodiments, the same operations and effects as the above-mentioned embodiments can be obtained. (1) In each of the above-described embodiments, it is determined whether or not the engine 1 is in the transient operation state based on the change value DNE regarding the engine rotation speed NE. On the other hand, the throttle opening T
It is also possible to determine whether or not the engine 1 is in the transient operation state based on the change amount and change rate of A or the change amount and change rate of the intake air amount Q.

(2) In each of the above embodiments, each spark plug 7
Also, the igniter 15 is provided as a knocking adjustment means for controlling knocking. On the other hand, a supercharger for adjusting the supercharging pressure and an EGR for adjusting the EGR amount
A device or the like may be provided as knocking adjustment means for controlling knocking. Alternatively, an injector may be provided as the knocking adjustment means to correct the amount of fuel injected from the injector.

(3) In each of the above embodiments, the LJ engine system is embodied in which the intake air amount Q is detected by the air flow meter 32 and the fuel injection amount control is executed. On the other hand, it is also possible to embody a DJ engine system in which the pressure in the intake passage is detected by a pressure sensor to control the fuel injection amount.

Further, it will be described below together with the effect that each of the above-described embodiments includes the following various embodiments according to the technical idea described in the claims. (A) In the invention according to claim 1, the occurrence degree calculating means calculates the degree of knocking occurrence for each magnitude of the engine rotation speed, and the correction value changing means calculates the engine based on the calculated degree of knocking occurrence. A knocking control device for an internal combustion engine configured to change the correction value according to the magnitude of the rotation speed.

According to this structure, during the transient operation of the internal combustion engine, the fuel consumption and output torque of the internal combustion engine are controlled in accordance with the magnitude of the engine rotation speed at that time while minimizing the occurrence frequency and magnitude of knocking. It can be improved to the maximum extent, and this can be achieved regardless of variation factors such as variations in characteristics of the internal combustion engine, knock detection means, etc., and changes with time.

In this specification, terms and the like relating to the constitution of the invention are defined as follows. (A) Knocking means air column vibration caused in a cylinder by a pressure wave generated by self-ignition of end gas in the cylinder. Due to this, a “crispy” sound is heard from the engine. In the engine equipped with a supercharger, which advances the ignition timing, raises the compression ratio in the cylinder,
The compression pressure in the cylinder becomes high near the full load, and knocking easily occurs. In general, weak knocking (trace knocking) has the effect of increasing both fuel consumption and output of the engine.

(B) Knocking control means that knocking is detected by a knock sensor or the like and the engine operation is controlled in a minute knocking state or a state immediately before the occurrence of knocking. Generally, responsive ignition timing control is used to retard the ignition timing when the occurrence of knocking is detected (determined), and advance the ignition timing when the occurrence of knocking is not detected (determined). Let

[0130]

According to the invention described in claim 1, the knocking determination level is calculated based on the value obtained by smoothing the detection value of the knock detecting means, and the determination level and the detection value of the knock detecting means are calculated. It is premised on a knocking control device that determines whether knocking occurs by comparison and controls the knocking based on the determination result. Then, when the internal combustion engine is in the steady operation state, the degree of occurrence of knocking is calculated based on the detection value of the knock detection means, and when the internal combustion engine is in the transient operation state,
In order to correct the calculation delay of the knocking determination level, the correction value is added to or subtracted from the knocking determination level, and the correction value is changed based on the calculated value of the degree of knocking occurrence.

Therefore, during the transient operation of the internal combustion engine, the knocking determination level is corrected by the correction value to be optimized regardless of the calculation delay caused by the smoothing processing, and the internal combustion engine is brought to the knocking determination level thus corrected. Variation factors such as variations in the characteristics of the engine and the knock detection means and their changes over time are reflected. As a result, the optimal knock determination level can be calculated according to the occurrence frequency and magnitude of knocking regardless of fluctuation factors such as variations in characteristics of the internal combustion engine and knock sensor and changes over time, and transient operation This has the effect of maximizing the fuel efficiency and output torque of the internal combustion engine while minimizing the occurrence of knocking.

[Brief description of drawings]

FIG. 1 is a basic conceptual configuration diagram according to the present invention.

FIG. 2 is a schematic configuration diagram of a gasoline engine system.

FIG. 3 is a block configuration diagram of an ECU.

FIG. 4 is a flowchart showing an “ignition timing control routine”.

FIG. 5 is a flowchart showing a “knocking determination processing routine”.

FIG. 6 is a flowchart showing a “maximum value calculation routine”.

FIG. 7 is a flowchart showing a “correction value learning update routine”.

FIG. 8 is a flowchart showing a continuation of the routine shown in FIG.

FIG. 9 is a flowchart showing a “patrol flag setting routine”.

FIG. 10 is a flowchart showing a “padding value calculation routine”.

FIG. 11 is a flowchart showing a “payment value calculation routine”.

FIG. 12 is a flowchart showing a continuation of the routine shown in FIG.

FIG. 13 is a graph showing function data of the maximum correction value and a predetermined value.

FIG. 14 is a graph showing function data of the minimum correction value and a predetermined value.

[Explanation of symbols]

1 ... Engine as internal combustion engine, 7 ... Spark plug, 15
... igniter (7 and 15 constitute knocking adjustment means), 36 ... knock sensor as knock detection means, 3
2 ... Air flow meter, 33 ... Throttle sensor, 35
... Water temperature sensor, 37 ... Rotation speed sensor (32, 33, 3
5, 37, etc. constitute an operating state detecting means), 41 ... E
CU (41 constitutes a judgment level calculation means, a knocking judgment means, a control means, an operating state judgment means, a judgment level calculation means, an occurrence degree calculation means, and a correction value change means).

Claims (1)

[Claims] 1. A knock detection means detects the magnitude of knocking generated in an internal combustion engine, compares the detected value with a knocking determination level, and determines whether knocking has occurred, and knocks based on the determination result. A knocking control device for controlling the occurrence of knocking by controlling the adjusting means, for calculating a knocking determination level based on a value obtained by smoothing the detection value of the knocking detection means. And a knocking determination means for determining the presence or absence of knocking by comparing the knocking determination level calculated by the determination level calculating means with the detection value of the knock detecting means, In order to control the occurrence of the Control means for controlling the knocking adjustment means, operating state detecting means for detecting the operating state of the internal combustion engine, based on the detection value of the operating state detecting means, the internal combustion engine is in a transient operating state Operating state determination means for determining whether it is a steady operating state, and the determination level for correcting the calculation delay of the knocking determination level when the determination result of the operating state determination means is a transient operating state Determination level correction means for adding or subtracting a correction value to the knocking determination level calculated by the calculation means, and knocking based on the detection value of the knock detection means when the determination result of the operation state determination means is a steady operation state. Occurrence degree calculation means for calculating the occurrence degree of, and the determination level correction means based on the calculated value of the occurrence degree calculation means. Knock control apparatus for an internal combustion engine, characterized in that a correction value changing means for changing the correction value.