JPH02108833A - Knock suppressing device for internal combustion engine - Google Patents

Abstract

PURPOSE:To make it possible to suppress knock to the level not offensive to the ear under a steady state by discriminating if a generated knock is a stationary one or a transient one from the generating interval of knocks and making incremental control for the control based on the knock level detected. CONSTITUTION:This suppressing device is provided with an acceleration sensor 1 detecting the vibratory acceleration of an engine, an analog gate 3 cutting down the noise of an interfering wave for knock detection out of the output signals passing through a frequency filter 2, a comparator 6 comparing the output voltages of the analog gate 3 and a noise level detector 5 to generate a knock detecting pulse, an integrator 7 integrating the output pulse to generate the integrated voltage according to knocking strength and a phase converter 8 shifting the position of a reference igniting signal. In this case, a knock interval detector 51 detecting the generating interval of a knock pulse which is an output of the comparator 6 and detecting whether an engine is in a transient operating condition is also provided to control the output characteristics of the integrator 7 so that it may increase when the transient operating condition is detected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a knock suppressing device for an internal combustion engine, and particularly to improving controllability during transient operation of the engine.

[Conventional technology]

FIG. 10 shows a conventional ignition timing control device for an internal combustion engine,
■ is an acceleration sensor that is attached to the engine and detects the vibration acceleration of the engine, 2 is a frequency filter that passes the signal component of the frequency that is sensitive to knocking among the output signals of acceleration sensor 1, and 3 is the output of frequency filter 2 4 is a gate timing controller that instructs the analog gate 3 to open or close in accordance with the timing of occurrence of interference noise; 5 is an engine other than knocking; 6 is a comparator that compares the output voltage of the analog gate 3 with the output voltage of the noise level detector 5 and generates a knock detection pulse; 7 is a comparator 6
8 is a phase shifter that shifts the position of the reference ignition signal according to the output voltage of the integrator 7, and 9 is a preset ignition advance. A rotation signal generator 1o generates an ignition signal according to the angular characteristics, and 1o shapes the output of the rotation signal generator 9 into a waveform.
A waveform shaping circuit 11 controls the closing circuit 1 of energization of the ignition coil 12 at the same time.
This is a switching circuit that cuts off and on the power supply of 2.

FIG. 11 shows the frequency characteristics of the output signal of the acceleration sensor 1, where A is the case where there is no knocking and B is the case where knocking occurs. In addition to the knock signal (signal generated due to knocking), the output signal of this acceleration sensor 1 includes:
This includes mechanical noise from the engine and various noise components on the signal transmission path, such as ignition noise. 8th
Comparing A and B in the figure, it can be seen that the knock signal has unique frequency characteristics. Therefore, although there are differences in the distribution depending on the engine or the mounting position of the acceleration sensor 1, there is a clear difference in each case depending on the presence or absence of knocking. Therefore, by passing the frequency component of this knock signal, noise of other frequency components can be suppressed, and the knock signal can be detected efficiently.

12 and 13 show operating waveforms of each part of the conventional device, and FIG. 12 shows a mode in which knocking does not occur,
FIG. 13 shows a mode in which knocking occurs. The operation of the conventional device will be explained using FIGS. 12 and 13. As the engine rotates, the ignition signal generated by the rotation signal generator 9 in accordance with preset ignition timing characteristics is waveform-shaped by the waveform shaping circuit IO into an opening/closing pulse having a desired closing angle. The switching circuit 11 is driven through the ignition coil 12 to intermittent the power supply to the ignition coil 12, and the engine is ignited and operated by the ignition voltage of the ignition coil 12 generated when the current flow is cut off. Engine vibrations occurring during operation of the engine are detected by an acceleration sensor 1.

If knocking is not occurring in the engine, engine vibration due to knocking will not occur, but due to other mechanical vibrations, the output signal of the acceleration sensor 1 will be affected as shown in Fig. 12 (a).
As shown in the figure, mechanical noise and ignition noise that rides on the signal transmission path occur during ignition.

This signal passes through the frequency filter 2
As shown in Figure 2 Q)), the mechanical noise component is considerably suppressed, but the ignition noise component is so strong that it may be output at a high level even after passing through the frequency filter 2. If this continues, the ignition noise will be mistakenly recognized as a knock signal, so the analog gate 3 is triggered by the output of the phase shifter 8, which is the output of the gate timing controller 4 (FIG. 12(C)). Close the gate and cut out ignition noise.

Therefore, only low-level mechanical noise remains in the output of the analog gate 3, as shown in FIG. 12(d).

On the other hand, the noise level detector 5 responds to changes in the peak value of the output signal of the analog gate 3, and in this case, has the characteristic of being able to respond to relatively gentle changes due to the peak value of normal mechanical noise. A DC voltage slightly higher than the peak value of the noise is generated (the opening in FIG. 12(d)).

Therefore, as shown in FIG. 12(d), since the output of the noise level detector 5 is larger than the average peak value of the output signal of the analog gate 3, the output of the comparator 6 for comparing these is as shown in FIG. As shown in (e), nothing is output, and all noise signals are eventually removed.

Therefore, the output voltage of the integrator 7 remains zero as shown in FIG. 12(f), and the phase shift angle by the phase shifter 8 (input/output FIG.
8) and (5) phase difference) also become zero.

Therefore, the open/close phase of the switching circuit 11 driven by this output, that is, the intermittent phase of energization of the ignition coil 12, is in phase with the reference ignition signal output from the waveform shaping circuit 10, and the ignition timing becomes the reference ignition timing.

In addition, when knocking occurs, the output of the acceleration sensor 1 includes a knock signal around a certain time delay from the ignition timing as shown in FIG. 13(a), and after passing through the frequency filter 2 and analog gate 3, The signal is shown in Figure 13(d).
As shown in (a), the knock signal is largely superimposed on the mechanical noise.

Since the rise of the knock signal among the signals passing through the analog gate 3 is steep, the response of the output voltage level of the noise level detector 5 to the knock signal is delayed. As a result, since the inputs of the comparators 6 each become 41 ports as shown in FIG. 13(d), pulses are generated at the outputs of the comparators 6 as shown in FIG. 13(e).

An integrator 7 integrates the pulse and generates an integrated voltage as shown in FIG. 13(f). The phase shifter 8 then outputs the output signal of the waveform shaping circuit 10 (13th
13 (chain (reference ignition signal)) to the delayed side in time, the phase of the output of the phase shifter 8 lags behind the phase of the reference ignition signal of the waveform shaping circuit IO. ) The switching circuit 11 is driven with the phase shown in ). As a result, the ignition timing is delayed and knocking is suppressed. in the end,
The conditions shown in FIGS. 12 and 13 are repeated to perform optimal ignition timing control.

14 to 19 show other conventional embodiments that facilitate cylinder-specific control for each cylinder, and in FIG. 14, 1 to 6 and 11.12 are the same parts as those in FIG. Therefore, the same reference numerals are given and the explanation is omitted. 21 is a cylinder pulse generator that generates a cylinder pulse corresponding to the ignition operation of each cylinder of the engine; 22 is a closed circuit that receives the cylinder pulse and outputs an ignition pulse whose closed circuit ratio is controlled to ensure the energization time of the ignition coil 12; A rate control circuit 23 is a phase shifter that performs angle retard control on the ignition pulse according to the control voltage and outputs it; 24 receives a knock pulse from the comparator 6 and outputs an integrated voltage proportional to its time width; This integrator is different from the integrator 7 of the conventional device shown in FIG. The integrated voltage is reset at each ignition. 25 is an AD converter that converts the integrated voltage of the integrator 24 into a digital signal and outputs it; 26 is a distribution circuit that distributes and outputs the digital signal in correspondence with the cylinder in which knock occurs; Since the case of the engine is shown, the output of this distribution circuit 26 is four outputs corresponding to the number of cylinders. Memories 27 to 30 each store a digital signal from the distribution circuit 26 corresponding to each cylinder. For example, the memory 27 stores the amount of knock occurring in one cylinder. 31 generates pulses at regular intervals, and the memory 27
A clock generator which inputs a pulse into the memory to subtract each stored value of ~30, 32 is the memory 27~3 mentioned above.
a selection circuit that selects and outputs only data corresponding to the ignition cylinder from each output of 0, a reference pulse generator 33 that generates a reference pulse corresponding to the reference cylinder among the four cylinders of the engine;
Reference numeral 34 denotes a cylinder selection pulse generation circuit that sequentially generates a cylinder selection pulse based on the reference pulse and the ignition pulse from the circuit closing rate control circuit 22 so as to make each operating state of the distribution circuit 26 and selection circuit 32 correspond to a predetermined cylinder. It is. 40 detects a failure such as a disconnection of the signal line between the acceleration sensor l and the frequency filter 2 or a short circuit to the ground, and
This is a fail detection circuit that detects an abnormal voltage output from the noise level detector 5, manually sends a fail signal to the integrator 24, and also sends a fail signal KF to other fuel control devices, vehicle diagnostic devices, etc. in parallel. .

15 and 16 are diagrams showing operating waveforms of the fourteenth answering section, and FIG.
Waveforms having the same reference numerals as in FIGS. 12 and 13 are the same portions as the waveforms in FIGS. 12 and 13, respectively.

First, when the basic operation is performed using FIGS. 2 and 3, and no knock occurs at the i gate, the two types of inputs to the comparator 6 become as shown in FIG. 15(d), and Since there is no knock signal at A in d), no pulse is output to the output of the comparator 6 as shown in FIG. do not have. For this reason, there are no stored values in the memories 27 to 3o, and there is no output from the selection circuit 32, so the input (FIG. 15(g)) and output (
There is no phase difference between 01)) in Fig. 15, and the ignition timing is at the reference position.

Next, a case where knock occurs in the engine will be explained using FIG. 16. The two types of inputs to the comparator 6 are as shown in Fig. 16(d), and the knock signal appears at A in Fig. 16(d), so the knock pulse is output from the comparator 6 as shown in Fig. 16(e). This pulse is integrated by an a-divider z4. Here, in order to perform knock detection corresponding to each cylinder, the output of the integrator 24 is reset by the output of the phase shifter 23 every time ignition occurs. Therefore, the output of the integrator 24 is held at a constant value during the period from knock detection to reset. These steps are performed for each ignition in the ignition cycle. This operation is different from conventional devices. The output (integrated voltage) of the integrator 24 is converted into a digital signal by an AD converter 25.

The distribution circuit 26 identifies the cylinder in which the knock occurs based on the cylinder selection pulse from the cylinder selection pulse generator 34, and stores information from the AD converter 25 in the memory 29 corresponding to the cylinder in which the knock occurs, for example, the third cylinder. Input the integrated voltage converted into a digital signal. The memory 29 stores the integrated voltage from the distribution circuit 26. i! The output circuit 32 selects the memory 29 corresponding to the third cylinder based on the cylinder selection pulse from the cylinder selection pulse generator 34 and outputs its output to the phase shifter 23 . Here, since knocking occurs in the third cylinder, the output of the memory 29 is selected and input to the phase shifter 23 during the ignition operation of the third cylinder. 16th
In the figure, knocking also occurs in the next cylinder, so if it is a normal four-cylinder engine, knocking would occur in the fourth cylinder. In this case, the output of the integrator 24 is
is selected and stored in the memory 30. The memory 3 is selected by the selection circuit 32 during the ignition operation of the fourth cylinder.
The output of 0 is input to the phase shifter 23.

Next, control for each cylinder will be explained in detail using the waveforms in FIG. Output of the device 24, (1), (k), (fl, 6Tl) (7)
Each # Me-1-I727 ~ Memory value of memory 30, (b)
is the output of the selection circuit 32, (80, (c) is the output of the phase shifter 2, respectively.
3 human power and output.

Now, as shown in FIG. 17(e), a knock pulse appears in the output of the comparator 6, and in order, the knock pulse appears in the third cylinder, the second cylinder,
Knocking occurs in the 3rd, 4th, and 2nd cylinders. These are converted into an integrated voltage by the integrator 24, and the output is as shown in FIG. 17(f), where Kl is 2.
3. 5 represents the knock level of detection, from the smallest to Kl.

K2. 3. K5 represents the largest knock, and at time t1, a knock occurs in the third cylinder, and the output of the integrator 24 becomes 5 in voltage. 5 to this voltage is AD
The signal is converted into a digital signal by the converter 25 and input to the distribution circuit 26 . The distribution circuit 26 adds 5 to the integrated voltage converted into a digital signal and stores it in the memory 29 at the ignition time t2 of the fourth cylinder.
It is stored in the memory 29 at time L2 for selective output. As a result, the voltage stored in the memory 29 becomes 5 (Fig. 17 ")".Next, a knock occurs in the second cylinder at time t3, and the integrated voltage is converted to 5 by the integrator 24.
This voltage 5 is converted into a digital signal by the AD converter 25, selectively inputted to the memory 28 by the distribution circuit 26, and stored in the memory 28 at time t4 (FIG. 17(b)).
). Time t4 is the ignition point of the first cylinder, after which the ignition operation of the third cylinder begins. At this time, since the voltage 5 is stored in the memory 29, the selection circuit 32 outputs the voltage as 5 (FIG. 17@) and inputs it to the phase shifter 23. As a result, the next ignition timing is retarded by the phase shifter 23 by an angle θ5 corresponding to 5 with respect to the above voltage (phase shifter 23
3 input (output (Fig. 17 (h) for the input (Fig. 17 (barrel)
)) is fired at time t5. Even though the ignition occurred at time t5, which was retarded by an angle θ5 from the reference ignition timing, knocking occurred again in the third cylinder at time t6. This level is 2, and the corresponding integrated voltage 2 is input to the memory 29 at the next ignition timing of the fourth cylinder (time t7). At this time, since 5 is already stored in the voltage in the memory 29, 2 is added to the voltage, and 7 is newly stored in the voltage ([+] in FIG. 17). time t7
(Reference ignition timing), time t8 is applied to the fourth cylinder.
A knock occurs and 3 is output as the integrated voltage. This voltage 3 is the next ignition timing of the second cylinder (time t9) and is stored in the memory 30.

On the other hand, the next ignition operation for the second cylinder is performed from time t7, but at this time, since 5 is stored in the voltage in the memory 28, 5 is selectively set to the voltage from the selection circuit 32 to the phase shifter 23.
is input. As a result, the next ignition timing is retarded from the standard by an angle θ5 corresponding to 5 for the above voltage L9.
becomes. In response to the ignition at time t9, a knock occurs in the second cylinder at time tlQ, and 1 is output as the integral voltage.

1 to this voltage is the time tit of the next ignition timing and the memory 28
The value stored in the memory 28 becomes 6 for the voltage.The ignition operation of the third cylinder starts from time tll, but since 7 is stored for the voltage in the memory 29 at this time, the next ignition timing t12 is The angle is delayed by θ7 from the standard. Thereafter, the retard control is repeated in the same way, and the ignition timing of the next fourth cylinder (time t
13) is retarded by an angle θ3 from the standard, and the next ignition timing of the second cylinder (time t14) is retarded by an angle θ6 from the standard.

As described above, when the ignition timing is retarded according to the amount of knock detected (integrated voltage) and knock no longer occurs in the engine, the ignition timing is then advanced toward the reference direction at a predetermined speed. , it is necessary to approach the knock limit. here,
Based on the clock from the clock generator 31, the stored values in the memories 27 to 30 are subtracted at a predetermined rate to make each stored value smaller, and the voltage input to the phase shifter 23 is reduced to adjust the retard angle. is made smaller to bring it closer to the standard.

As described above, if the phase shifter 23, integrator 24 to selection circuit 32, and cylinder selection pulse generation circuit 34 in this embodiment are configured using a computer, detailed control including engine fuel control can be developed. It is easy to use and can be used to upgrade to a more advanced system.

Further, as in the conventional device shown in FIG. 10, it is also possible to uniformly retard all cylinders by the same angle; in this case, the distribution circuit 26 and selection circuit 32 for cylinder selection are fixed. , it is sufficient to use only one of the memories 27 to 30, and it is also possible to switch between the individual cylinder control and the all-cylinder control as described above to perform the control as appropriate.

The fail detection circuit 40 detects a disconnection of the signal line connecting the acceleration sensor 1 and the frequency filter 2, a short circuit to the ground, etc.
A fail signal KF is output when the output of the acceleration sensor 1 is no longer normally input to the frequency filter 2. Generally, disconnection of the signal line is most likely to occur (for example, due to poor contact at the connector). Furthermore, a fail signal KF is also output when the operating state of the noise level detector 5 becomes abnormal. This is because even if the signal line between the acceleration sensor l and the frequency filter 2 is in a normal state, it may deviate from the normal setting state for some reason, for example, the processed signal may become very large, and the comparison standard may not work properly. It detects that it is no longer possible to output voltage and outputs a fail signal KF. Integrator 2
When the fail signal KF is input from the fail detection circuit 40, the circuit 4 operates independently of the signal from the comparator 6 and outputs the integrated voltage at the time of fail. Figures 18 and 19
The figure shows an example of the integrated voltage at the time of the above failure.

The example shown in FIG. 18 basically outputs the maximum integrated voltage V, MAX that the constant integrator 24 can output, but the ignition timing (time of symbol F) is controlled by the ignition signal of the output of the phase shifter 23. ), and is repeatedly set to zero for each ignition. In FIG. 19, the integrator 24 is not reset by the ignition signal output from the phase shifter 23, and the fail signal KF from the fail detection circuit 40 is shown.
Therefore, it is only necessary to invalidate the manual ignition signal to the integrator 24. If the integrated voltage V@MAX is constantly outputted in this way, the voltage . MAX is stored and set to a desired fail-time ignition timing at which knock does not occur.

Here, the maximum value ■ of the output of the integrator 24 at the time of failure.

Although it is controlled at MAX, any other intermediate value may be used, and it can be determined by taking into account the knocking characteristics and other characteristics of the engine. In addition, the above fail signal KF can be input to the fuel control device for comprehensive engine control, or can be input to a diagnostic device to issue an alarm and perform even more comprehensive control including other control devices. It is also possible to develop it into more advanced control.

[Problem to be solved by the invention]

Since the conventional knock suppressor is configured as described above, it is possible to suppress the knock value to a desired value or less (usually a small knock below the so-called trace knock), but in a transient operating state during acceleration, each part of the engine Due to fluctuations in operating conditions due to differences in transient characteristics, knocks occur more frequently than during steady operation, and control characteristics that can suppress trace knock during steady operation are insufficient to control knocks that occur during these transient times, resulting in less control during transient times. Sexuality becomes worse. In other words, there is a problem in that knocking during transient periods is large or trace knocking occurs more frequently over a long period of time than during steady operation, resulting in an unpleasant knocking state that gives an unpleasant feeling.

This invention was made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a knock suppression device that can control the knock that occurs during transient operation of an engine to the suppression level during steady operation, and that does not cause knock for a long period of time. purpose.

[Means to solve the problem]

The knock suppression device according to the present invention includes a knock sensor that detects engine knock information, and a knock discriminator that selects knocks occurring in each cylinder of the engine based on the output of the sensor, and is based on the output of the knock discriminator. In a knock suppressing device that controls a knock generating element to suppress knock occurring in an engine, the control amount for controlling the knock generating element is increased as the output generation interval of the knock discriminator becomes shorter.

[For production]

In this invention, the means for increasing the control amount activated during transient operation increases the control amount for the knock detection amount during transient operation than during steady operation, and suppresses it to a level one level smaller than trace knock during transient operation. So,
Responsiveness during transient operation can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

First, we will explain the basic principles of this invention.6 The knock that occurs in the internal combustion engine during steady operation under fixed conditions (the level is trace knock due to the control action) occurs at intervals of several seconds or more. The test results showed that this characteristic has almost no relation to engine speed or load.

On the other hand, for knocks that occur during transient operation, initially the control amount is insufficient due to the basic principle of feedback control (responsiveness), and knocks larger than trace knocks occur, and then the control amount becomes sufficient for individual knocks. Each knock is suppressed to the trace knock level, but since these knocks occur at intervals of 0.1 seconds or less and in large numbers, which is much shorter than during steady operation, trace knocks occur over a long period of time. Tests confirmed that the sound became harsh and controllability deteriorated. By focusing on the characteristics of the engine that can be confirmed from such tests, the knock order interval is determined, and from this it is possible to identify whether the engine is in steady operation or transient operation, and the control weight is increased during transient operation.

The above-mentioned knock occurrence interval characteristics during steady state and transient state are shown in FIG. 1, and the horizontal axis represents time.

Here, Fig. 1(a) shows knock occurrence during steady state, and although the knock occurrence intervals T, ``rx, and T'' are different times, they all have in common that they are long periods of several seconds or more. On the other hand, FIG. 1(b) shows knock occurrence during a transient period, where the knock occurrence interval is T,, -'-=T,.

are each 0.1 seconds or less, and are characterized in that they occur at time intervals that are orders of magnitude shorter than the regular knock occurrence intervals T and ~T shown in FIG. 1(a).

Next, embodiments of this invention will be described. Figure 2 is the first
For the conventional device shown in Fig. 0, the knock occurrence interval is detected from the output (knock pulse) of the comparator 6, and when the knock occurrence interval is short, the output characteristic of the integrator 7 with respect to the knock pulse is increased. It is designed to control changes. In FIG. 2, numerals 1 to 12 are the same parts as in FIG. 10, so the same reference numerals are given and the explanation will be omitted.

Reference numeral 51 is a knock interval detector which detects the generation interval of knock pulses which is the output of the comparator 6, and detects that the engine is in a transient operating state when knock pulses appear at an interval of 0.1 seconds or less, for example. be. When the engine is in a transient operating state,
As shown in FIG. 1(b), the knocks that occur appear in a short period of time, the interval between each occurrence being 0.1 seconds or less, so the knock interval detector 51 detects that a transient knock is occurring, and the comparator The output characteristic of the integrator 7 with respect to the knock pulse from the integrator 6 is controlled so that it becomes large.

Next, the operation will be explained with reference to FIG. The figure (e) shows the knock pulse output from the comparator 6, and the figure (f) shows the output from the integrator 7. (e) As shown in the figure, for the 1st knock α1, Nα
Since the two knocks α2 occur at intervals of 0.1 seconds or less, the knock interval detector 51 detects that these are transient knocks when the two knocks α2 appear, and changes the characteristics of the integrator 7. control. As a result, the integrator 7 has Nα2 knocks α in a steady state where the knock occurrence interval is a long time of several seconds or more.
The output for 2 is V+ (corresponding to FIG. 13(f)), but for NO, which is a transient knock, and 2 knock α2, it is Vl.
The larger ■, (broken line in FIG. 3(f)) is output. Since the output of the integrator 7 corresponds to the phase shift angle in the phase shifter 8, phase shift control (retard angle control) of the angle corresponding to the above-mentioned (2) is performed. As a result, the retard angle control is performed in accordance with the frequency of knock occurrence during transient operation, which occurs frequently in a short period of time, and control can be performed with good responsiveness.

The above-mentioned embodiment is an example in which the output characteristics with respect to the input of the integrator 7 are controlled. Next, an embodiment in which the output characteristics of the integrator 7 are controlled so as to add a certain amount to the output will be described with reference to FIG.

In this figure, numerals 1 to 12 are the same parts as in the conventional device shown in Fig. 10 and the embodiment shown in Fig. 2, so the same reference numerals are given and the explanation thereof will be omitted. 52 is a knock interval detector that detects the generation interval of the output pulses of the comparator 6, and 53 is a pulse generator that generates a pulse that operates the integrator 7 for a certain period of time based on the output of the detector 52.

FIG. 5 shows the output of the comparator 6 (FIG. 5(e)) and the output of the integrator 7 (FIG. 5(f)) in FIG.
), when Nα2 notch α2 occurs within 0.1 seconds of the previous knock (Nα1 notch αI), the knock interval detector 52 detects that these knocks α1°α are transient knocks, Tell the way. Pulse generator 53
receives the output of the knock interval detector 52 and inputs a pulse with a predetermined time width to the integrator 7.

Since the integrator 7 responds to the pulses from the comparator 6 and also generates an output in response to the pulses from the pulse generator 53, it integrates the voltage as shown in FIG. 5 [f]. The device 7 outputs. That is, in FIG. 5(f), the solid line indicates the output from the comparator 6 for the pulse, and the broken line indicates the output for the pulse from the pulse generator 53. The output rise V2 of 7 is the output in response to the pulse from the comparator 6, and the output rise V12 is the output in response to the pulse from the pulse generator 53. Since the output V2 is in response to the pulse from the comparator 6, it is equivalent to the characteristic of the conventional device shown in FIG. 13(f).

With the embodiment described above, the knock level of the generators is suppressed to a small knock below the trace knock, which is the suppression level during steady operation, in response to transient knocks that occur frequently in a short period of time during transient engine operation. This is to suppress the knock in the transient operation region that occurs at the level to a level below the trace knock, and to obtain controllability of the trace knock level that is not as harsh as that during steady operation.

By the way, the knock that occurs in the engine is caused by many factors such as gasoline octane number, intake air temperature, intake air humidity, water temperature, rotation speed, and load. 1□ performs various controls based on the information on the knock occurrence factors, and can achieve accurate control of the - layer.

Next, referring to FIG. 6, a description will be given of an embodiment in which the present invention is applied to the conventional device shown in FIG. 14, which has been described as a system suitable for detecting the knock level for each knock detection.

In FIG. 6, 1 to 6 and 21 to 334o are the same parts as those shown in FIG. 14, so their explanation will be omitted. 61
is a knock interval detector that detects the occurrence of transient knock from the pulse interval of the output of the comparator 6.

A knock interval detector 61 determines the pulse interval of the output of the comparator 6, and if the generation interval is 0.1 W or less, it is detected that the engine is in a transient operation state and that transient knock is occurring. . When a transient knock is detected, the integrator 24
In order to increase the output (retard control voltage) by 1, we changed the response characteristics of the comparator 6 to the knock pulse, and
Increase the number of 4s than in the steady state. It is also easily possible to further change and control this response characteristic to change the amount of increase.

In this case, each time a knock occurs, the knock level for each cylinder where knock occurs is detected and controlled, so even when transient knock occurs as described above, the knock level is detected and controlled only for the cylinder where knock occurs.
Transient knock control is performed based on the knock detection level, and since transient knock occurs sequentially in each cylinder, transient knock control is performed for each cylinder in sequence in response to this.

Next, another embodiment will be explained with reference to FIG.

This FIG. 7 shows only the part related to the embodiment of the present invention of the conventional device shown in FIG.
These are the same parts as those in the figure, and their explanation will be omitted.

In FIG. 7, 62 is a knock interval detector that detects a transient knock from the interval of output pulses of the comparator 6, and 63 is a pulse generator that outputs a pulse of a predetermined time width according to the output of the transient knock interval detector 62. It is.

When the interval between the output pulses of the comparator 6 is 0.1 ms or less, the knock interval detector 62 detects the occurrence of a transient knock and outputs an output. In accordance with this, the pulse generator 63 outputs a pulse with a predetermined time width and inputs it to the integrator 24, so that the integrator 24 increases its output in response to the transient knock. As in the case of FIG. 6, control is performed for each cylinder in which knock occurs each time knock occurs, so transient knock control is sequentially performed for cylinders in which transient knock occurs each time transient knock occurs.

It is easily possible to increase the output of the integrator 24 by changing and controlling the pulse width generated by the pulse generator 63.

FIG. 8 shows another embodiment, similar to FIG. 7, only the parts related to the embodiment of the present invention.
are equivalent parts. 64 is an increase correction signal generator that outputs an analog amount for transient increase correction in accordance with the output from the knock interval detector 62. 65 is an adder that adds the output of the integrator 24 and the analog amount from the increase correction signal generator 64.

The knock interval detector 62 outputs an output every time a transient knock is detected, and in response, the increase correction signal generator 64 outputs an increase correction signal of a predetermined analog amount.

Since the adder 65 adds up each analog signal from the integrator 24 and the increase correction signal generator 64 and outputs the result, when a transient knock is detected, the increase correction signal is added to the output of the integrator 24.
Control is performed to increase the amount by a predetermined amount. In this case as well, it is easily possible to change and control the increase value from the correction increase detector 64, and more detailed control can be achieved.

In all of the embodiments described above, increase correction was performed using an analog quantity, but an embodiment in which increase control is performed using a digital quantity (digital signal) will be described with reference to FIG.

This figure shows the AD converter 25 and memories 27 to 30, which are the parts to which the embodiment of the present invention applies, and the clock generator 31 connected to the memories 27 to 30 is not shown. Knock interval detectors 71 to 74 are provided corresponding to the memories 27 to 30, and detect transient knocks in each cylinder from the generation intervals of digital control signals output from the distribution circuit 26 corresponding to each cylinder. , the increase signal is input to each of the memories 27 to 30 as a digital signal.

In each of the above embodiments, the occurrence of transient knock is detected only from the knock occurrence interval, but in addition to this, the magnitude of the occurrence level is also judged, and the The occurrence of a large knock may be determined to be a transient knock, and the amount increase correction may be performed based on this, which can be easily applied to any of the embodiments.

Furthermore, if the correction increase is made larger as the knock occurrence interval becomes shorter, finer control can be performed, and a similar knock suppression effect can be obtained. In this case, when controlling the characteristics of the integrator as in the embodiment shown in FIG. 2, Vl+ shown in FIG. 3 may be increased as the pulse interval from the comparator 6 becomes shorter. Furthermore, when the correction amount is added to the integrator output as in the embodiment shown in FIG. 4, Vat shown in FIG. 5 may be increased as the pulse interval from the comparator 6 becomes shorter.

〔Effect of the invention〕

As explained above, according to the present invention, in a knock suppression device for an internal combustion engine that detects engine knock and controls knock generation elements according to its magnitude to suppress knock, The system determines whether the knock is a steady knock or a transient knock, and performs increased control based on the detected knock level.By simply and easily detecting the knock interval, it is possible to eliminate harsh knocks that occur at short intervals. Knock can be suppressed with good responsiveness, and can be suppressed to a level that is not jarring in steady state conditions.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are knock occurrence interval characteristic diagrams in a knock suppression device for an internal combustion engine according to an embodiment of the present invention;
Figure 2 is a block diagram of the knock suppressor, Figure 3(e),
(f) is an explanatory diagram of the operation in Fig. 2, and Fig. 4 is a knock control'
FIG. 5(e) is a block diagram of another example of the 4Il device. (f) is an explanatory diagram of the operation of FIG. 4, FIG. 6 is a block diagram of another example of the knock suppressing device, FIGS. 7 and 8 are block diagrams of main parts according to the present invention, and FIG. The figure is a block diagram of an example of increasing control using a digital amount.
The figure is a block diagram of a conventional device, FIG. 11 is a frequency characteristic diagram of an acceleration sensor, FIGS. Figure 14 is a block diagram of another example of the conventional device, and Figures 15 (a) to (b).
16(a) to (b) are operating waveform diagrams of the device in FIG. 14, FIG. 17 is an operating waveform diagram for each cylinder, and FIGS. 18 and 19 are operating waveform diagrams when the integrator fails. be. 6... Comparator, 7... Integrator, 51... Knock interval detector. Note that the same reference numerals in the figures indicate the same or equivalent parts. Agent Masuo Oiwa Figure 1 Figure 2 Figure 3 Figure 5 Ichisakiseki-Pr1. ! lI Fig. fig. fig. fig.

Claims (1)

[Claims] Equipped with a knock sensor that detects engine knock information and a knock discriminator that selects knocks that occur in each cylinder of the engine based on the output of this sensor, and controls the factors that generate knocks based on the output of the knock discriminator to control knock occurrences that occur in the engine. 1. A knock suppressing device for an internal combustion engine, characterized in that a control amount for controlling a knock generating element is increased when an output generation interval of the knock discriminator becomes shorter.