JPH06323191A - Knocking control device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Purpose] Despite the engine variations and changes over time,
To provide a knocking control device for an internal combustion engine capable of maximizing vehicle power performance while suppressing knocking. A shift time determination means 3 for determining whether or not a shift is being performed during a transition is provided, and when the shift determination means 3 determines that a shift is being performed during a transition Knocking determination level changing means 4 is provided for changing the knocking determination level during shifting during transition depending on whether or not the occurrence of knocking is detected. Then, the knocking determination means 2 compares the detection value from the knock sensor 1 with the changed knocking determination level to determine whether knocking has occurred.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a knocking control system for an internal combustion engine, and more particularly to detecting knocking occurring in the internal combustion engine by a knock sensor and comparing the detected value with a knocking determination level to determine whether knocking has occurred. The present invention relates to a knocking control device for an internal combustion engine for detecting.

[0002]

2. Description of the Related Art When an air-fuel mixture in a cylinder of an internal combustion engine burns abnormally, the pressure in the combustion chamber rises much faster than during normal combustion. Therefore, each time combustion occurs in each cylinder, a knocking sound such as a hammer is repeatedly generated. Combustion in a state where slight knocking occurs is preferable from the viewpoint of fuel consumption, torque, etc. However, if the frequency, magnitude, etc. of knocking exceeds the allowable range, it becomes unfavorable for the engine.

Therefore, an engine ignition timing control device for controlling knocking by detecting the frequency or magnitude of knocking and retarding or advancing the ignition timing based on the detection result to feedback control the ignition timing is provided. Conventionally known (Japanese Patent Laid-Open No. 57-32065).

In this conventional apparatus, the background signal, which is the criterion for determining whether knocking has occurred, is obtained by smoothing the detected value from the knock sensor.
When the engine speed suddenly changes, for example, during acceleration, there is a delay in tracking the background signal, which is the criterion for determining the presence or absence of knocking when the output of the knock sensor signal increases. It may be judged. Therefore, in order to prevent this erroneous determination, the knocking determination level is raised during a transient period when the engine speed suddenly changes, for example, during acceleration, and a knocking determination level different from the steady state is set, and knocking due to the delay in tracking the background signal is performed. It compensates for the lack of judgment level.

[0005]

However, in the above-mentioned conventional apparatus, the amount of increase in the knocking determination level at the time of acceleration is fixed, so that the optimum knocking determination level changes due to engine variations or aging. In the case where the knocking determination level demanded amount of raising has changed, the set amount of raising becomes larger than the required amount of raising, and even if knocking occurs, it is not judged as knocking, or the setting is made. There is a possibility of making an erroneous determination that the amount of raising becomes smaller than the required amount of raising and knocking is determined even though knocking has not occurred.

The present invention has been made in view of the above points, and changes the knocking determination level during transition to an optimum level in accordance with the presence or absence of knocking during speed change during transition, thereby causing variations in engine An object of the present invention is to provide a knocking control device for an internal combustion engine, which can maximize the power performance of a vehicle while minimizing knocking regardless of changes over time.

[0007]

FIG. 1 is a block diagram showing the principle of the present invention.

As shown in the figure, according to the present invention, a knock sensor 1 for detecting knocking of an internal combustion engine is compared with a knocking determination level detected by the knock sensor to determine whether knocking has occurred. Judgment means 2
In the knocking control device including the above, when the gear shift determination means 3 for determining whether or not the gear shift during the transition is in progress, and the gear shift determination means 3 determines that the gear shift during the transition is in progress, Knocking determination level changing means 4 for changing the knocking determination level during shifting during transition depending on whether or not the occurrence of knocking is detected during shifting.

[0009]

The shift determining means determines whether or not the shift is in transition. When it is determined that the gear shift is being performed during the transition, the knocking determination level changing means changes the knocking determination level when the occurrence of knocking is detected during the gear shifting. This changed knocking determination level is compared with the detection value from the knock sensor, and the presence or absence of knocking is determined based on the comparison result. Knocking is controlled by retarding or advancing the ignition timing based on the determination result and feedback controlling the ignition timing.

Therefore, it is possible to maximize the dynamic performance of the vehicle while minimizing knocking, regardless of engine variations, secular changes, and the like.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 2 is a main part configuration diagram of an internal combustion engine (engine) including the knocking control device according to the present invention.

As shown in the figure, an intake air temperature sensor 12 and a throttle valve 1 are provided downstream of an air cleaner (not shown).
3 are provided. The throttle valve 13 includes a throttle opening sensor 1 for detecting the opening of the throttle valve 13.
4 is attached.

Further, in the throttle opening sensor 14,
An idle switch (not shown) that is turned on when the throttle valve is fully closed (when idle) is provided. The intake air temperature sensor 12 is arranged on the intake pipe wall upstream of the throttle valve 13. Further, a surge tank 16 is arranged downstream of the throttle valve 13. The surge tank 16 includes an intake manifold 18, an intake port 19 and an intake valve 20.
Is communicated with the combustion chamber 22 of the engine body 21 via.
A fuel injection valve 23 is attached to the intake manifold 18 so as to correspond to each cylinder.

The combustion chamber 22 includes an exhaust valve 24 and an exhaust port 2
5 and an exhaust manifold 26 to communicate with a three-way catalyst (not shown). The exhaust manifold 26 is provided with an O ₂ sensor 27 that detects the residual oxygen concentration in the exhaust gas and outputs a signal inverted at a value corresponding to the theoretical air-fuel ratio.

The cylinder block 28 has the knock sensor 1 for detecting knocking generated in the combustion chamber 22.
A knock sensor 29 corresponding to the above and a water temperature sensor 30 that is arranged so as to discharge into the water jacket and detects the cooling water temperature are attached. The cylinder head 31 has spark plugs 3 that project into the combustion chambers 22.
2 is attached. The spark plug 32 includes a distributor 33 and an igniter 34 including an ignition coil.
Is connected to an electronic control unit (hereinafter referred to as an ECU) 35 including a microcomputer or the like.

The distributor 33 includes a cylinder discriminating sensor 36 and a rotation angle sensor 3 each having a signal rotor fixed to a distributor shaft and a pickup fixed to a distributor housing.
7 is attached. The cylinder discrimination sensor 36 outputs a cylinder discrimination signal, for example, every 720 ° C., and the rotation angle sensor 37 outputs a rotation angle signal, for example, every 30 ° C. Then, from the cycle of this rotation angle signal, the engine speed (NE)
Can be calculated.

As shown in FIG. 3, the ECU 35 includes a micro processing unit (MPU) 38, a read only memory (ROM) 39, a random access memory (RAM) 40, and a backup RAM (B-RA).
M) 41, an input / output port 42, an input port 43, output ports 44 and 45, and a bus 46 such as a data bus or a control bus connecting these.

An analog-digital (A / D) converter 47 and a multiplexer 48 are sequentially connected to the input / output port 42, and the intake air temperature sensor 12 is connected to the multiplexer 48 via a buffer 49. With
The water temperature sensor 30 and the throttle opening sensor 14 are connected via the buffer 50 and the buffer 51, respectively.
Further, the pressure sensor 17 is connected to the multiplexer 48 via the buffer 52. The input / output port 42 is connected to the A / D converter 47 and the multiplexer 48, and the output from the intake air temperature sensor 12, the output from the pressure sensor 17 and the water temperature sensor 30 are output from the MPU 38 according to the control signal. Output and throttle opening sensor 14
It is controlled so that the output from the A / D converter is sequentially A / D converted at a predetermined cycle.

An O ₂ sensor 27 is connected to the input port 43 via a comparator 53 and a buffer 54, a cylinder discrimination sensor 36 and a rotation angle sensor 37 are connected via a waveform shaping circuit 55, and a buffer (not shown) is connected. The idle switch 15 is connected via. The output port 44 is connected to the igniter 34 via the drive circuit 56, and the output port 45 is connected to the fuel injection valve 23 via the drive circuit 57.

The ECU 35 having the above-mentioned hardware configuration realizes the shift determining means 3 and the knocking determination level changing means 4 as software processing operations. The knocking control operation performed by the ECU 35 will be described below.

FIG. 4 is a knocking determination level raising permission determination routine, and this routine is a process executed by interruption every fixed time, for example, every 64 ms.

First, at step 100, the absolute value | DLNE | of the engine speed (NE) change amount DLNE during the cycle of 64 ms in which this routine is executed is 8rp.
It is determined whether or not m is less than m, that is, whether or not acceleration / deceleration during a transition is being performed. Then, when it is determined that | DLNE | is not less than 8 rpm, that is, during acceleration / deceleration during a transition, it is determined in step 102 whether the cooling water temperature THW detected by the water temperature sensor 30 is less than 60 ° C., When it is determined that the cooling water temperature THW is not lower than 60 ° C., the process proceeds to step 104, and the fail safe flag XKFA
It is determined whether IL is 1 or not. The fail-safe flag XKFAIL is a flag that becomes 1 when the knock sensor 29 or the like has a failure. And step 104
If it is determined that the failsafe flag XKFAIL is not 1, the counter CKC is determined in step 106.
SN is incremented by 1 and the process is step 11
Go to 0.

In step 110, the counter CKCS
It is determined whether or not N is equal to or greater than 48 ms, that is, whether the cooling water temperature is 60 ° C. or higher, there is no fail, and the acceleration / deceleration state during a transition is continued for 48 ms or more.
Is determined to be equal to or greater than 48 ms, the raising permission flag XKCSN is set to 1 in step 112 to permit raising of the knocking determination level, and this routine is ended.

On the other hand, in step 100, the engine speed (N
When it is determined that the absolute value | DLNE | of the change amount in E) is less than 8 rpm, that is, when it is determined that the acceleration / deceleration during the transition is not being performed, it is determined in step 102 that the cooling water temperature THW is less than 60 ° C. When it is determined in step 104 that the fail safe flag XKFAIL is 1,
That is, when it is determined that the knock sensor 29 or the like has a failure, the counter CCKSN is cleared to 0 in step 108, and further, the raising permission flag XKC is set in step 114.
SN is cleared to 0, raising of the knocking determination level is prohibited, and this routine ends.

Further, when it is determined in step 110 that the counter CCKSN is less than 48 ms, it is determined that the cooling water temperature is 60 ° C. or higher and there is no failure, and the acceleration / deceleration state during the transient does not continue for 48 ms or more. If so, the raising permission flag XKCSN is cleared to 0 in step 114, raising of the knocking determination level is prohibited, and this routine is ended.

FIG. 5 is a routine for calculating the knocking determination level and changing the amount of raising the knocking determination level.
This routine is a process that is executed by interruption every fixed time, for example, every 64 ms. Note that Steps 200 to 206 and Step 218 described below are a knocking determination level calculation routine, and Step 20
Steps 8 to 216 are a knocking determination level raising amount changing routine.

First, in step 200, a table search is performed for the value of the adaptation constant K from the engine speed (NE), and the background level VMEAN is multiplied by this K value to calculate the knocking determination reference value VMM. Where the fitness coefficient K
Is a constant uniquely determined by the engine speed (NE), and the background level VMEAN is obtained by smoothing the detection value from the knock sensor 29.

Next, in step 202, it is judged whether or not the raising permission flag XKCSN is 1, that is, whether or not raising is permitted in the raising determination routine of FIG.
When XKCSN is 1 and it is determined that the raising is permitted, the raising amount tVOSNE is set to a predetermined amount (4 in this embodiment) in step 204, and it is determined in step 208 whether the raising amount increase flag XKCSNL is 1 or not. To be done.

Here, the increase flag XKCSN
L will be described with reference to FIG. FIG. 6 is a routine for determining an increase in the amount of raising, and this routine is a process executed by interruption every fixed time, for example, each cylinder TDC.

First, at step 300, it is judged if the raising permission flag XKCSN is 1 or not.
Is determined to be 1, that is, if the raising of the knocking determination level is permitted, step 302
At, it is determined whether or not the ignition retard amount AECT during gear shifting is equal to or greater than a predetermined amount (20 ° C. A in this embodiment). When the ignition retard amount AECT during shifting is 20 ° C. or higher,
That is, the engine speed (NE) suddenly changes and the knocking determination level is raised, but when the ignition timing is retarded and knocking does not occur, it is determined in step 304 whether knocking is detected. If it is determined that knocking has been detected, it is determined that an erroneous determination is made because the amount of raising of the knocking determination level is insufficient, and in step 306, the amount of raising of lift amount XKCSN is increased.
L is set to 1, the increase in the amount of raising is permitted, and this routine ends.

On the other hand, if it is determined in step 300 that the raising permission flag XKCSN is not 1, that is, if raising is prohibited, the raising amount increase flag XKCSNL is set to 0 in step 308. Then, the increase of the raising amount is prohibited, and this routine is finished. Further, when it is determined in step 304 that knocking is not detected, it is impossible to determine whether the knocking determination level is too large or is appropriate. Therefore, in step 308, the raising amount increase flag XKCSNL is set. Is set to 0, the increase in the amount of raising is prohibited, and this routine ends.

Incidentally, S302 of this routine corresponds to the above-mentioned shift determining means.

Returning to the explanation of FIG. 5 again, at step 208, the increase flag XKCSNL described in FIG.
If it is determined that the knocking determination level is not increased, the step 2 is performed.
In 12, it is determined whether or not the knocking-free determination counter CVOSNL is greater than or equal to a predetermined value (10 counts in this embodiment). If it is determined that the count is greater than or equal to 10 counts, knocking must be determined because the amount of raising is excessive. Judgment is made, and the correction amount tVO of the previous raising amount is determined in step 214.
The SNL _i-1 is decremented by 1 count to calculate the correction amount tVOSNL of the current lift amount, and the knocking absence determination counter CVOSNL is cleared to 0. That is, the knocking-free determination counter CVOSNL
Is counted up when knocking is not detected while the raising is permitted, and is cleared when knocking is detected. The initial value of the correction amount tVOSNL for the amount of raising is set to 0 by the initial routine.

Next, in step 216, the amount of increase tVOSNE determined in step 204 and the correction amount tVOSNL of the current amount of increase calculated in step 214 are added to obtain the amount of increase tVOSNE.
Knocking criterion V calculated in step 200 in 18
The new knocking determination reference value VLEV1 is calculated by adding MM and the amount of raising calculated in step 216, and this routine is ended.

On the other hand, when it is determined in step 208 that the increase flag XKCSN is 1, that is, when the increase in the knocking determination level is allowed, the previous increase amount of the lift amount is determined in step 210. Correction amount t
The VOSNL _i-1 is incremented by one count to calculate the correction value tVOSNL of the current lift amount, and thereafter, the same processing of step 216 and step 218 as described above is performed in this order, and this routine is ended.

When it is determined in step 202 that the raising permission flag XKCSN is not 1, that is, when raising is prohibited, the raising amount t
VOSNE is set to 0 and the same step 218 as described above is performed without raising the volume, and this routine ends. Therefore, in this case, the new knocking determination reference value VLEV1 calculated in step S218 is the same value as the knocking determination reference value calculated in step 200. That is, when it is determined in step 110 that the acceleration / deceleration during the transition is not being performed, the knocking determination level is not increased.

Then, the knocking determination means 2 compares the new knocking determination reference value VLEV1 calculated in step 218 of FIG. 5 with the detection value from the knock sensor 29, and the detection value from the knock sensor 29 is determined. When it is larger than the new knocking determination reference value VLEV1, it is determined that knocking has occurred, while the value detected by the knock sensor 29 is the new knocking determination reference value VLE.
When it is V1 or less, it is determined that knocking does not occur. Then, based on the result of this determination, the knocking is controlled by retarding or advancing the ignition timing to perform feedback control of the ignition timing.

According to the present embodiment as described above, the gear shift determination means 3 determines whether or not the gear shift is in transition, and when it is determined that the gear is in transition, the knocking determination level changing means 4 is used. The knocking determination level is changed to the optimum level based on whether or not knocking is detected during shifting, and the knocking is optimally controlled based on the changed knocking determination level. It is possible to maximize the power performance of the vehicle while minimizing knocking.

In the above embodiment, step 20
The amount of increase tVOSNE in 4 is not limited to 4, for example, tVOSN corrected in step 216.
It may be a value or the like based on the learning result obtained by learning and learning E.

[0040]

According to the present invention, the knocking determination level at the time of transition is changed to the optimum level, and the knocking is controlled based on this optimum level. Therefore, the knocking can be performed regardless of engine variations or secular changes. It is possible to maximize the power performance of the vehicle while minimizing it.

[Brief description of drawings]

FIG. 1 is a principle configuration diagram of the present invention.

FIG. 2 is a configuration diagram of an engine equipped with a knocking control device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a hardware configuration of an ECU.

FIG. 4 is a flowchart showing a knocking determination level raising permission determination routine.

FIG. 5 is a diagram showing a routine for calculating a knocking determination level and changing the amount of raising the knocking determination level.

FIG. 6 is a diagram showing a routine for determining an increase in a raised amount.

[Explanation of symbols]

 1, 29 Knock sensor 2 Knocking judgment unit 3 Shift judgment unit 4 Knocking judgment level changing unit 12 Intake sensor 13 Throttle valve 14 Throttle opening sensor 17 Pressure sensor 20 Intake valve 22 Combustion chamber 23 Fuel injection valve 30 Water temperature sensor 32 Spark plug 33 Distributor 34 Igniter 35 Electronic Control Unit (ECU) 37 Rotation Angle Sensor

Claims (1)

[Claims] 1. A knocking control device comprising: a knock sensor for detecting knocking of an internal combustion engine; and knocking determination means for comparing the detection value from the knock sensor with a knocking determination level to determine whether knocking has occurred. In the above, in the shift change determination means for determining whether or not the shift is in transition, and when the shift change determination means determines that the shift is in transition, the occurrence of knocking is detected during the shift. A knocking control device for an internal combustion engine, comprising: knocking determination level changing means for changing a knocking determination level during a gear shift at the time of transition depending on whether or not the transition is made.