JPH076873B2 - Engine knocking detector - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a device for detecting engine knock.

(Prior Art) An engine including a knock sensor for detecting a knocking state of the engine and controlling the engine based on a signal from the knock sensor to suppress knocking is known.

For example, JP-A-58-28597 discloses an example of a knocking control method. In this disclosed method, the engine is equipped with a vibration detecting element for detecting vibration, and the average value of the amplitude values of the electric signal from this vibration detecting element in a plurality of ignition cycles is calculated separately for each cylinder. The occurrence of knocking is stored for each cylinder, and the ignition timing is controlled in the retard direction for each cylinder.

Further, Japanese Patent Laid-Open No. 58-208432 discloses a similar knocking detection device.

(Problems to be Solved) In the engine disclosed in JP-A-58-28597, knocking is detected for each cylinder, and ignition timing control corresponding to each cylinder is performed. ,
It is possible to perform knocking control with higher accuracy than a method in which knocking control is uniformly performed for each cylinder. In this type of knocking control device, knocking is detected by focusing on the fact that the vibration level in a normal operating state in which knocking does not occur and the vibration level when knocking occurs are different. Therefore, in order to perform appropriate knocking control, it is premised that the vibration level in a normal state where knocking does not occur is accurately grasped. In this case, the engine vibration level differs between when the engine is in the combustion stroke and when it is in the non-combustion period, but knocking occurs during the combustion period.Therefore, when detecting knocking, the vibration level during the combustion period is used as a reference. It is desirable to judge.

In the engine disclosed in Japanese Unexamined Patent Publication No. 58-28597, knocking is detected based on the vibration level during the combustion period, so that the operating condition is such that the vibration level during a certain combustion period is stable. Then, there is an advantage that knocking can be detected with high accuracy. But,
In an operating state in which the vibration level of the engine changes, for example, in a transient operating state such as during acceleration, there is a problem that proper knocking detection becomes difficult.

Further, in the device disclosed in JP-A-57-208432,
Since knocking is determined only on the basis of the vibration level in the non-combustion period, there is a problem that accurate knocking detection cannot be performed.

(Means for Solving Problems) As described above, the vibration level of the engine is different between the combustion period and the non-combustion period and also changes with the operating state.
Therefore, even if a certain reference for knocking determination is set based on the vibration level in the combustion period over the entire operating region, knocking cannot be accurately determined.
Therefore, in order to set an accurate knocking determination level, it is necessary to appropriately consider the vibration level in the combustion period and the vibration level in the non-combustion period according to the operating state. The present invention is configured in consideration of such circumstances and has the following configuration. That is, the control device of the present invention creates a first reference value from a vibration detection means for detecting engine vibration and an output from the vibration detection means and a vibration level in the combustion period of the engine.
Second reference value creating means for creating a second reference value from the vibration level of the engine in the non-combustion period, which receives the outputs of the reference creating means and the vibration detecting means; and an operating state detecting means for detecting the operating state of the engine. In the steady operation of the engine, receiving the output from the operating state detecting means, the first comparing means for comparing the output of the vibration detecting means with the first reference value to determine knocking, and the operating state detecting means. When the engine is in an accelerating operation, a second comparison means for comparing the output of the vibration detection means with the second reference value to determine knocking is provided.

According to the present invention, in detecting knocking,
Means for creating a first reference value based on the vibration level during the combustion period and a second reference value based on the vibration level during the non-combustion period are respectively provided, and during steady operation in which no change in the vibration level occurs, combustion is performed. Knocking detection is performed by the first reference value based on the vibration level of the period. In a transitional operating state such as during acceleration when the vibration level in the combustion period changes, knocking is determined based on the second reference value based on the vibration level in the non-combustion period.

(Effects of the Invention) According to the present invention, knocking is detected based on the vibration level in the combustion period with the highest accuracy, and since the vibration level changes in this combustion period, knocking detection based on this vibration level is performed. During transient operation, where reliability is reduced, knocking is detected based on the vibration level during the non-combustion period. Therefore, according to the present invention, it is possible to perform knocking detection with high accuracy regardless of changes in the operating state, and thereby to perform accurate knocking control.

(Description of Embodiments) Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIG. 1, the engine 1 of this example is a four-cylinder reciprocating engine, and each cylinder includes a piston 3 that slides inside a cylinder block 2. A space above the piston 3 constitutes a combustion chamber 4, and an intake port 5 and an exhaust port 6 are opened in the combustion chamber 4. An intake valve 7 and an exhaust valve 8 are combined with the intake port 5 and the exhaust port 6, respectively. An intake passage 9 communicates with the intake port 5, and an air cleaner 10 is attached to the upstream end of the intake passage 9. At the downstream side of the air cleaner 10, an air flow meter 11 that detects the intake air amount
However, the throttle valves 12 are arranged further downstream, respectively. An intake air temperature sensor 11a for detecting the intake air temperature is attached to the air flow meter 11. Also throttle valve 1
A surge tank 13 is formed on the downstream side of 2, and an injector 14 for injecting and supplying a fuel amount is arranged further downstream to form an intake system. The exhaust passage 15 communicates with the exhaust port 6 to form an exhaust system.

Further, an ignition plug 16 is exposed to the combustion chamber 4, and an ignition coil unit 17 is provided to control the ignition timing of the ignition plug 16.

Further, a water temperature sensor 19 for detecting a cooling water temperature is attached to a water jacket 18 formed in the cylinder block 2, and a knock sensor 20 for detecting knocking by detecting engine vibration is attached. Furthermore, in the cylinder head of the engine 1 of this example,
A crank angle sensor 21 that detects a crankshaft rotation angle from the rotation of a camshaft (not shown) is provided. In the engine 1 of the present example, a signal for identifying the cylinder can be obtained from the signal from the crank angle sensor 21.

Further, the engine 1 of this example is provided with a controller 22 preferably including a microcomputer in order to control fuel injection and ignition timing. Further, the engine 1 of this example is provided with a knock detection circuit 23 that cooperates with the controller 22 to detect knocking.

Signals representing the intake air amount and the intake air temperature from the air flow meter 11 and the intake air temperature sensor 11a are input to the controller 22, respectively.

The controller 22 also receives a throttle opening sensor 12a for detecting the opening of the throttle valve 12, a signal from the water temperature sensor 19, a crank angle signal and a cylinder identification signal from the crank angle sensor 21, and a starter signal. It is like this. It should be noted that the signal indicating the engine vibration from the knock sensor 20 is once input to the knock detection circuit 23, is subjected to predetermined processing in the knock detection circuit 23, and then is input to the controller 22.

As for the signal from the knock sensor 20 input to the knock detection circuit 23, only the signal having a frequency within a predetermined range is selected by passing through the bandpass filter 24.

In the knock detection circuit 23, the signal passed through the bandpass filter 24 is adapted to be directly input to the comparator 25, and half-wave rectification integration is performed via switches 26 and 27, which are preferably semiconductor switches. It is adapted to be input to circuits 28 and 29.

The switches 26 and 27 are selectively opened at a predetermined timing in response to a command from the controller 22, so that the signal passed through the bandpass filter 24 is activated by the switches 26 and 27 functioning as a gate circuit. It is selectively input to the half-wave rectification integration circuit 28 or 29 accordingly. Half-wave rectification integrator circuits 28 and 29 are circuits for determining the determination level for performing knock determination, and integrate the signal of the corresponding switch 26 or 27 during the open period, and switch 26 or 27 is closed. At that moment, the integrated value is input to the controller 22.

The switch 26 is opened when the cylinder is not in the combustion period, and the switch 27 is opened when the cylinder is in the combustion period. Therefore, the half-wave rectification integration circuit 28 determines the knocking determination comparison level during the non-combustion period, and the half-wave rectification integration circuit 29 determines the knocking determination comparison level during the combustion period. Then, these half-wave rectifying and integrating circuits 28 and 29 are
The knocking determination comparison level signal determined by the switch 22 is selectively output from the controller 22 to the comparator 25 in response to the operation of the switches 26 and 27, and the bandpass filter 24
Is compared with the signal after passing through, and the level of knocking is determined by this.

The signal indicating the knocking necessity I _K output from the comparator 25 is once input to the integrating circuit 30 and integrated for a predetermined time. The period during which the signal is integrated in the integrating circuit 30 is controlled by the controller 22. Further, the controller 22 outputs a reset signal to the half-wave rectification integration circuits 28 and 29 and the integration circuit 30 at a predetermined timing to clear these circuits.

The control of this example will be described below.

FIG. 3 shows a flowchart of the background routine of the control of this example. The controller 22 constantly executes this background routine.

Referring to FIG. 3, the controller 22 first initializes the system and reads signals from various sensors.

That is, the signals from the air flow meter 11, the water temperature sensor 19, the intake air temperature sensor 11a, the starter signal for detecting the drive state of the engine, and the idle switch signal for detecting the idle state are read. Next, the controller 22 operates the read data to calculate the intake air amount. At the same time, the change amount ΔQ _a of the intake air amount is calculated.
Next, the controller 22 executes the transient determination flag setting subroutine shown in FIG. 4 to set the flag F _A for determining whether the engine 1 is in the transient state.

Referring to FIG. 4, the controller 22 determines the change amount | ΔQ _a |
Is above the predetermined position Kg, it is determined that the engine 1 is in a transient state, that is, in an unsteady state such as an acceleration state or a deceleration state. In this case, the flag F _A is set to 1. On the other hand, when the intake air change amount | ΔQ _a | is smaller than the predetermined position Kg, the controller 22 determines that it is in the steady state and the flag F _A
Is set to 0. In this example, even if the flag F _A is once set to 1 after the transient state is determined, even if the intake air change amount | ΔQ _a | decreases and the engine 1 returns to the steady state thereafter. The flag F _A is kept at 1 until the combustion state of the engine 1 stabilizes after a lapse of a predetermined time. That is, when the flag F _A is set to 1, the controller 22 changes the intake air change amount | ΔQ _a |
If but becomes smaller than the predetermined value Kg, set the timer C to a predetermined value K _A, until the timer C is 0 so as to reduce the timer C for each execution of the routine, the flag F _A
Is maintained at 1.

Next, control of ignition timing as knocking control according to one embodiment of the present invention will be described.

FIG. 5 shows a flowchart of the interruption routine. The interruption routine of FIG.
Each time a cylinder identification signal generated every 0 ° is input to the controller 22, it is interrupted and executed.

Further, FIG. 6 shows a flow chart of an interrupt routine for controlling the knock detection circuit 23 to obtain an appropriate knock correction advance angle Θ _Kn and finally determining the ignition timing to be output.

The interrupt routine of FIG. 6 is executed every time the crank angle signal generated every 30 ° of crank rotation angle is input to the controller 22 regardless of the execution of the background routine of FIG. 3 and the transient determination flag setting routine of FIG. It is designed to be interrupted and executed.

When the interrupt routine of FIG. 5 is executed, the cylinder discrimination counter n and the sixth cylinder for performing knock correction control
The counter T for determining the work procedure of the routine shown in the figure is forcibly reset and set to n = 0 and T = −1, respectively.

Referring to the time charts of FIGS. 6 and 7, the controller 22 first increments the counter T by one each time this routine is executed. Since the engine 1 of this example is a 4-cycle engine, and the interrupt routine of FIG. 6 is executed every 30 ° of crank rotation, the cylinder stroke is executed every 6 times of this routine. Will be switched. Since the routine of FIG. 6 is designed to control each cylinder corresponding to the expansion stroke of each cylinder, the controller 22 sets T = 0 when the crank angle signal is input six times. Reset. Also, at this time,
Since the next cylinder starts the expansion stroke in the ignition order, the controller 22 increments the cylinder discrimination counter n by one. Further, in this routine, the cylinder identification counter m for the cylinder to start the expansion stroke next is prepared, and 1 is also added to this counter m. The engine 1 of this example has four
Since it is a cylinder engine, when the counter m reaches 4, m = 0 is set. Next, the controller 22 performs a predetermined process according to the value of the counter T.

When the counter T is 2, the controller 22 first closes the switch 27 functioning as the gate for the knock signal of the combustion period of the knock detection circuit 23 shown in FIG. 2, and the switch functioning as the gate of the non-combustion period. Open 26. Then, the controller 22 reads the integration value I _F for half-wave rectifying and integrating circuit 29 for integrating the signal from the knock sensor 20 in order to make the knock determination comparison level S _Fn cylinders each combustion period.
Further, the controller 22 uses an integration circuit 30 that represents the knock strength.
Read the integral value I _K of. Next, the controller 22
A knock intensity determination and a knock correction advance value Θ _Kn are calculated for each cylinder by executing a subroutine shown in the figure for determining a knock strength advance and a ignition correction advance angle Θ _Kn . Further, the controller 22 executes the comparison level calculation subroutine shown in the flow chart of FIG. 9 in the state of the counter T = 2 to determine whether the knock determination comparison level S _{Fn in the} combustion period and the knock determination comparison level S _{Fn in the} combustion period are different from each other. A correction coefficient D _n between the knock determination comparison level S _N and the combustion period is obtained.

When the counter T = 3, the controller 22 executes the subroutine for calculating the control value of the ignition advance kernel shown in the flowchart of FIG. 10 to calculate the final ignition advance Θ _I9 .

At the counter T = 4, the controller 22 closes the switch 26 functioning as a gate during the non-combustion period and integrates the signal from the bandpass filter 24 to obtain the knock determination comparison level S _N during the non-combustion period. Circuit 28
Read the integral value I _N of. In addition, the controller 22
The subroutine shown in the figure is executed to calculate the knock determination comparison level S _N during the non-combustion period and determine the output value S _OUT to the comparator 25.

When the counter T = 5, the controller 22 outputs the knock determination comparison level output value S obtained by the subroutine of FIG.
_OUT is output to the comparator 25 and each of the integration circuits 28, 29 and 30 of the knock detection circuit 23 is reset.

At counter T = 0, the controller 22 opens the burn period gate or switch 27.

Then, when the counter T = 6, the expansion stroke of the cylinder is completed, so the controller 22 causes the counter T to end.
Is reset to 0, and the cylinder identification counters n and m
Is added one by one. As a result, when the interrupt routine of FIG. 6 is executed next, the series of operations described above is performed for the cylinder for which the expansion stroke is started next.

Next, a procedure for obtaining various variables used in the interrupt routine of FIG. 6 will be described.

First, referring to FIG. 9, a knock determination comparison level S _Fn for each cylinder and a correction coefficient D _n for calculating a knock determination comparison level S _N for a non-combustion period from the comparison level S _Fn. The procedure for obtaining is described.

In FIG. 9, the controller 22 indicates the oldest knock strength I _F stored in the map A (n, 300) that stores the signal from the integrating circuit 30 representing the knock strength I _F in the combustion period for each cylinder. to erase. In this example, the integration circuit for each cylinder
The data from 30 are stored in the map A (n, 300) for 300 pieces.

Next, the controller 22 is stored in a predetermined storage location for the cylinder at the output or map the latest knock intensity I _F A of the integrating circuit 30 (n, 300). Next, the controller 22 obtains the average value A of the knock intensity I _F of the cylinder is stored. Then, this average value A is multiplied by a constant correction coefficient K _F to calculate a knock determination comparison level S _Fn in the combustion period of the cylinder.

Next, the controller 22 corrects the knock determination comparison level S _Fn in the combustion period of the cylinder and updates the correction coefficient D _n for obtaining the knock determination comparison level S _N in the non-combustion period.

In this case, in this example, in order to obtain the knock determination comparison level S _N in the reliable non-combustion period, whether or not knocking has occurred is monitored and the counter C _T is used, and when knocking does not occur for a certain period of time, The correction coefficient D _n is updated only when the operating state of the engine 1 is a steady state. That is, when knocking occurs, the counter C _T is set to 300, and when knocking does not occur, the counter C _T is decremented by 1 to obtain the counter C _T.
If There is and flag F _A = 0 if becomes 0, the first time to determine the specific E _n of the knock determination comparison level S _N of the knock determination comparison level S _Fn and non-combustion period of the combustion period and this ratio E _n The correction coefficient D _n is updated by multiplying the current correction coefficient D _n .

Next, the procedure for obtaining the knock determination comparison level S _N in the non-combustion period and the procedure for obtaining the comparison level output value S _OUT for the comparator 25 will be described with reference to FIG.

In Figure 11, controller 22, non-combustion obtained in non-signal representative of the knock intensity of the combustion period I _N, a constant correction factor K _m, O _m and routines of the ninth diagram is output from the integrating circuit 30 Using the correction coefficient D _n between the knock determination comparison level S _N of the period and the knock determination comparison level S _Fn of the combustion period, the knock determination comparison level S _N of the non-combustion period is set to S _N = (K _m × I _N + O _m ) ×
Give as D _n . Since the knock determination comparison level S _N obtained in this routine is required for the cylinder to be subjected to the expansion stroke next, the coefficients K _m , O _m and D _n used to obtain this comparison level S _N are The value corresponding to the cylinder that performs the expansion stroke is used next.

Since knocking occurs when the cylinder is in the combustion state, it is desirable to make a determination using the knock determination comparison level of the combustion period in order to accurately determine whether knocking has occurred. However, when the engine is in a transient state such as during acceleration, the vibration level due to combustion changes, so it is difficult to set the knock determination comparison level for the appropriate combustion period.

In view of such circumstances, in the present example, in setting the knock determination comparison level, the controller 22 outputs to the comparator 25 depending on whether the operating state is a steady state or a transient state such as acceleration. Set the proper knock judgment comparison level output value S _OUT . During transient operation in which the combustion vibration level of the engine changes, that is, when the flag F _A is 1, the controller 22 sets the knock determination comparison level S _N in the non-combustion period as the output value S _OUT . Further, when the engine is in steady operation, that is, when the flag F _A is not 1, the controller 22 sets the knock determination comparison level S _Fn in the combustion period as the output value S _OUT .

Next, referring to FIG. 8, the ignition timing knock correction advance angle Θ
_The procedure for _{obtaining Kn} will be described.

In this example, the vibration generated in each cylinder is detected by using the single knock sensor 20, and knocking is detected by comparing the knock determination comparison level S _Fn and the vibration detection value set for each cylinder in advance, and the value is constant. The knocking occurrence status of the period is examined, the averaging process is performed to determine the knocking strength within that period, and the ignition timing control is performed for each cylinder based on this result, whereby knock control is performed. There is. Therefore, the knock sensor 20 must distinguish the input engine vibration signal and judge knocking for each cylinder.

However, in this configuration, since the positional relationship with the knock sensor 20 differs depending on the cylinder, the level of the signal indicating the engine vibration input to the knock sensor 20 differs depending on the cylinder.

In this embodiment, in view of these circumstances, the average sets the knock determination comparison level S _Fn for each cylinder, i.e. determination cycle J _n for determining knocking for each cylinder, a knock intensity generated separately The period for calculating the knocking strength for the ignition timing control by changing the processing is changed according to the cylinder.

In this case, in this example, the determination cycle J _n is set to be longer as the detection sensitivity of the knock sensor 20 becomes lower, for example, as the cylinder is farther from the knock sensor 20.

Further, in this example, learning control for the knock correction advance angle Θ _Kn is also performed, and the cycle R _n for updating this learning value is also the same as the knock determination cycle J _n of the knock sensor 20. The cylinders with lower detection sensitivity are made longer.

Next, the controller 22 determines whether or not the operating region is in the feedback region for performing knock control, and if it is not in the feedback region, the ignition timing is not corrected by the knock correction advance angle Θ _Kn. Therefore, in this example, the value of the knock correction advance angle Θ _Kn and other parameters are cleared.

If it is in the feedback area, the controller 22 determines a zone configured by subdividing the feedback area. Then, when the zone is the same as when the present routine was executed last time, the knock correction advance angle Θ _Kn stored as the learning value is adopted as the knock correction advance angle Θ _Kn to be used for the control.

Next, the controller 22 determines from the output value of the integrating circuit 30 whether knocking has occurred.

When knocking occurs, the controller 22 stores the strength I _K of each knocking in a predetermined memory location B (n, C _En ) corresponding to the cylinder and determines the value of the flag F _B. , It is determined whether the knocking is the first knocking in the knocking determination cycle.

And if the knock is the first one,
Controller 22 depending on the value of the knock intensity I _K, determines the determination period L _n for determining the average level of the knocking intensity I _K.

In this case, when the determination cycle L _n is once determined, it is not preferable to change the cycle L _n during the determination period, so the flag F _B is set to 1 so that the determination cycle does not change. There is.

Then, the counter C _En determination period plus one counter C _En
This routine is repeatedly executed until L _n is reached. When knocking does not occur during the determination period, 0 is stored in the predetermined storage location B (n, C _En ).

However, in the knock determination operation described above, when the knocking strength I _K is large, it is desirable to perform prompt knock control regardless of whether the determination period is in progress. When the knocking intensity larger than the knocking strength I _K detected at the beginning of the determination period occurs, the determination work is immediately stopped and the knock correction advance angle Θ _Kn is calculated. That is, when the first knocking strength B (n, 0) is larger than the detected knocking strength I _K , the counter C at that time is counted.
The value of _En is put in the value of the cycle L _n to change the cycle.

Then, the controller 22 obtains the average value of the knocking strength I _K stored in the storage location B (n, C _En-1 ) when the predetermined determination period has elapsed. Further, the controller 22 calculates an ignition timing correction amount Θ _K according to the value of the determined average knocking strength I _K.

Next, the controller 22 corrects the current knock correction advance angle Θ _Kn with this correction amount Θ _K to obtain a new knock correction advance angle Θ _Kn.
Set _Kn .

Further, in this case, the controller 22 is the counter C _En ,
Clear flag F _B.

Further, in the ignition timing control of the cylinder, it is desirable to keep the ignition timing appropriate by making the retard amount as small as possible unless an abnormality such as knocking occurs. From this point of view, in this example, if knocking does not continue for a certain period of time, the knocking correction advance angle Θ _Kn is corrected to be small.
That counter when the knocking using C _Fn does not occur, if the counter C _Fn each time so as to add the counter C _Fn reaches a certain value J _n × K _J is set for each cylinder, the current knock by subtracting a predetermined value ΔΘ from the correction advance theta _Kn, it sets a new knock correction advance theta _Kn.

Further, the controller 22 stores the knock correction advance angle Θ _Kn newly set in the above procedure in the map for learning value calculation.
Then, if the learning value update conditions such as whether the operation state is steady, the operation state of the same zone continues for a predetermined time, and the learning value update period R _n has passed, the learning value of the zone is satisfied. Update Θ _GnMAP .

Next, the procedure for obtaining the ignition advance angle Θ _Ig for giving the final ignition timing will be described with reference to the flowchart of the ignition timing control routine shown in FIG.

Referring to FIG. 10, the controller 22 first determines from the read various data whether or not the engine 1 is in the starting state, and if it is in the starting state, sets the ignition timing to a predetermined constant value. . Next, the controller 22 determines whether the engine is in the idle state and, if it is in the idle state, calculates the idle advance angle Θ _IDL and sets it as the ignition advance angle Θ _Ig . Further, in an operating state that is neither the start-up nor the idle state, that is, in the normal operating state, the controller 22 determines the basic advance angle Θ _BASE using a map based on the engine speed N _e and the intake air amount Q _a. To do. In this case, the controller 22 further calculates the water temperature correction advance angle Θ _{WT of the} ignition timing based on the signal from the water temperature sensor 19 and the intake temperature correction advance angle Θ _{A based} on the signal from the intake temperature sensor 11a.

Next, the controller 22 reads out the knock correction advance angle Θ _Kn obtained by executing the interrupt routine shown in the flowcharts of FIGS. 6 and 7.

Further, the controller 22 calculates the acceleration correction advance angle Θ _ACC for performing the advance angle correction in the acceleration state, and at the same time calculates the various advance angle correction values obtained in the above procedure to obtain the final ignition advance value. Ignition advance angle Θ _Ig that should be output as Θ _Ig = Θ _BASE +
It is given as Θ _AT + Θ _WT − Θ _Kn − Θ _ACC .

Then, the controller 22 stores the finally obtained ignition advance value Θ _Ig in a predetermined internal counter until the ignition timing of the cylinder.

As described above, according to the control of the present example, in calculating the knocking strength I _K of each cylinder obtained by the averaging process for the fixed period, the knock determination period is set according to the sensitivity of the signal in the knock sensor 20. Therefore, it is possible to more appropriately determine the knocking strength. Therefore, in the engine of this example, the ignition advance angle Θ _Ig for each cylinder can be appropriately calculated using the single knock sensor 20, and as a result, accurate knock control by ignition timing control can be performed. .

In this example, the case where the ignition timing is controlled to perform knock control has been described, but the present invention is not limited to the ignition timing,
The present invention can be similarly applied to any control that is performed on a factor that affects the operating state that is effective for suppressing knocking.

[Brief description of drawings]

FIG. 1 is an overall schematic diagram of an engine according to an embodiment of the present invention, FIG. 2 is a detailed diagram of a knock detection circuit, FIG. 3 is a background routine flowchart, and FIG. 4 is a transient determination flag setting routine flowchart. FIG. 5 is a flowchart of an interrupt routine executed when a cylinder identification signal is input, FIG. 6 is a flowchart of an interrupt routine executed when a crank signal is input, and FIG. 7 is correspondence of various signals. A time chart showing the relationship, FIG. 8 is a flowchart of a subroutine for calculating knock intensity determination and knock correction advance angle, FIG. 9 is a flowchart of a subroutine for obtaining a knock determination comparison determination level in the combustion period, and FIG. 10 is ignition advance. FIG. 11 is a flowchart of a subroutine for calculating the angle, and FIG. 7 is a flowchart of a subroutine for calculating a comparison determination level output value to a knock detection circuit. 1 ... Engine, 2 ... Cylinder block, 3 ... Piston, 4 ... Combustion chamber, 5 ... Intake port, 6 ... Exhaust port, 7 ... Intake valve, 8 ... Exhaust valve, 9 ... Intake aisle,
10 …… Air cleaner, 11 …… Air flow meter, 12
...... Throttle valve, 13 ...... Surge tank, 14 …… Injector, 15 …… Exhaust passage, 16 …… Spark plug, 20 ……
Knock sensor, 21 …… Crank angle sensor, 22 …… Controller, 23 …… Knock detection circuit, 24 …… Band pass filter, 25 …… Comparator, 26,27 …… Switch, 28,29 ……
Half-wave rectification integrator circuit, 30 ... Integrator circuit.

Claims (1)

[Claims] 1. A vibration detecting means for detecting engine vibration,
A first reference creating unit that receives an output from the vibration detecting unit and creates a first reference value from a vibration level in an engine combustion period, and a second reference value from an output of the vibration detecting unit from a vibration level in an engine non-combustion period Second reference value creating means for creating a reference value for the engine, an operating state detecting means for detecting an operating state of the engine, and an output from the operating state detecting means. The first comparing means for comparing the output with the first reference value to determine knocking and the output from the operating state detecting means receive the output from the vibration detecting means and the first comparing means during the acceleration operation of the engine. An engine knocking detection device, comprising: a second comparison unit that compares the reference value of 2 to determine knocking.