JPS63159668A - Ignition control device for internal combustion engine - Google Patents

Abstract

PURPOSE:To enable all the cylinders to be efficiently operated, by providing an integrator, which outputs integrated voltage on the basis of an output of a knocking discriminator further resets the integrated voltage corresponding to the ignition action, and enabling an amount of knocking to be detected in every cylinder in proportion to the generated amount of knocking. CONSTITUTION:In the case of an engine having a comparator 6 which generates a knocking pulse by inputting an output of an acceleration sensor 1, detecting vibrative acceleration of the engine, through a frequency filter 2 and an analog gate 3 to be compared with an output of a noise level detector 5, an integrator 24, which receives the knocking pulse from the comparator 6 outputting integrated voltage in proportion to its time width, is provided. This integrator 24 is constituted so as to reset said integrated voltage in every ignition in the time of ignition on the basis of an output ignition pulse of a phase shifter 23 which functions so as to perform a delay timing control of an angle corresponding to control voltage. And the engine, which controls the phase shifter 23 to shift a phase through a distribution circuit 26 and memories 27-30 or the like corresponding to an output of the integrator 24, controls an ignition coil 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application] The present invention relates to an ignition timing control device for an internal combustion engine, and particularly to suppression of knocking.

[Conventional technology]

FIG. 7 shows a conventional ignition timing control device for an internal combustion engine.
2 is an acceleration sensor attached to the engine and detects the vibration acceleration of the engine; 2 is a frequency filter that passes signal components of frequencies that are sensitive to knocking among the output signals of acceleration sensor 1; 3 is the output signal of frequency filter 2; Of these, 4 is an analog gate that cuts off noise that becomes a disturbance wave in response to knock detection, and 4 is a gate timing control m+ that instructs the analog gate 3 to open or close in response to the timing of occurrence of disturbance noise.
11.5 is a noise level detector that detects the level of mechanical vibration noise of the engine other than knocking, and 6 is a comparison that compares the output voltage of the analog gate 3 and the output voltage of the noise level detector 5 to generate a knock detection pulse. vessel, 7 is comparison 1
An integrator that integrates the output pulse of m6 and generates an integrated voltage according to the knocking intensity, 8 a phase shifter that shifts the position of the reference ignition signal according to the output voltage of the integrator 7, and 9 a preset ignition signal. A rotation signal generator that generates an ignition signal according to the advance angle characteristic; 10 a waveform shaping circuit that shapes the output of the rotation signal generator W#9; and 11 a waveform shaping circuit that simultaneously controls the closing angle of energization of the ignition coil 12; This is a switching circuit that cuts off and on the power supply to the ignition coil 12 based on the output signal of the phase converter 8.

FIG. 8 shows the frequency characteristics of the output signal of the acceleration sensor 1. A is a case where there is no knocking, and B is a case where knocking occurs. The output signal of the acceleration sensor 1 includes, in addition to a knock signal (a signal generated due to knocking), mechanical noise of the engine and various noise components on the signal transmission path, such as ignition noise. Comparing A and B in FIG. 8, 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 depending on the presence or absence of knocking in each case. 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.

9 and 10 show operating waveforms of each part of the conventional device, and FIG. 9 shows the mode in which knocking does not occur,
Figure 0 shows the mode in which knocking occurs. The operation of the conventional device will be explained using FIGS. 9 and 10. 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 10 into an opening/closing pulse having a desired closing angle. through the switching circuit 11
The engine is ignited and driven by the ignition voltage of the ignition coil 12 which is generated when the ignition coil 12 is powered on and off, and the ignition coil 12 is interrupted.

Engine vibrations occurring during operation of this engine are detected by the acceleration sensor 1.

If engine knocking is not occurring, engine vibration due to knocking will not occur, but due to other mechanical vibrations, the output signal of the acceleration sensor 1 may include mechanical noise and Ignition noise is generated on the signal transmission path at ignition [1]F.

This signal is passed through the frequency filter 2.
As shown in FIG. 1b), 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. At this rate, ignition noise becomes a knock signal! ! ! ! = E, the analog gate 3 closes the gate for a certain period of time from the ignition timing using the output of the gate timing controller 4 (FIG. 9(C)) triggered by the output of the phase shifter 8, thereby suppressing the ignition noise. Cut off.

Therefore, only low-level mechanical noise remains in the output of the analog gate 3, as shown in FIG. 9 (dl).

On the other hand, the noise level detector 5 responds to changes in the peak value of the output (No. 1) of the analog gate 3, and in this case has a characteristic that it can respond to relatively gentle changes due to the peak value of normal mechanical noise. A DC voltage slightly higher than the peak value of mechanical noise is generated (Fig. 9 fd)).

Therefore, as shown in FIG. 9 (dl), 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, a comparator 6 is used to compare them.
Nothing is output as shown in FIG. 9(e), and all noise signals are eventually removed.

Therefore, the output voltage of the integrator 7 remains zero as shown in Fig. 9(f), and the phase shift angle by the phase shifter 8 (input/output Fig. 9(g)
, [phase difference of h)) also becomes 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.

However, when knocking occurs, the output of the acceleration collapse sensor 1 includes a knocking signal around a certain time lag from the ignition timing, as shown in FIG. 10(a), and the frequency filter 2 and analog gate The signal after passing through 3 is shown in Figure 10 (
As shown in A of dl, the knock signal becomes a large 'M1' multiplication of the II tag noise.

Among the signals passing through this analog gate 3, knock (3
Since the rise of the knock signal is steep, the response of the output voltage level of the noise level detector 5 to the knock signal is delayed. As a result, the inputs of the comparators 6 are respectively 42 in FIG. 10(d).
Therefore, panosis occurs in the output of comparison M6 as shown in FIG. 10 tel.

Integrator@7 integrates the pulse and generates an integrated voltage as shown in FIG. 1O(f). Then, the phase shift Wj8 is the integral v4
The output signal of the waveform shaping circuit 10 (FIG. 10 (g) (reference ignition signal)) is phase-shifted to the delayed side in accordance with the output voltage of the phase shifter 8. Shaping circuit 10
The switching circuit 11 is driven with the phase shown in FIG. 10(h), which is delayed from the phase of the reference ignition signal. As a result, the ignition timing is delayed and knocking is suppressed. Eventually, the conditions shown in FIGS. 9 and 10 are repeated to achieve optimal ignition timing control.

[Problem that the invention seeks to solve]

Since the conventional device is configured as described above, the speed at which the output of the integrator 7 is reduced (the ignition timing advances toward the reference by 61
The speed at which the engine returns to 1) is a large time constant on the order of t milliseconds per degree of engine rotation angle. This reduction rate is
This characteristic is important for control because it prevents the ignition timing from advancing too quickly and suddenly entering the knock region, causing a large knock.

Therefore, in order to obtain the knock detection amount for each knock detection from the output of the integrator 7, obtain the outputs of the integrator 7 immediately before and after the knock detection, and calculate the difference between the respective values, that is, 1
It is necessary to determine the change in the output of the integrator 7 due to the knock detection, which requires complicated calculations. This cannot be determined by simply reading the value of the integrator 7 at the time of knock detection. Therefore, for example, it is necessary to store the output of the integrator 7 before the knock occurs, and when a knock occurs, to find the difference between the output of the integrator 7 immediately before the knock occurs and the output immediately after the knock occurs.

On the other hand, recent engine controls are becoming more and more sophisticated, and there is a tendency to finely control each cylinder to bring all cylinders into a better combustion state and increase engine output. In order to carry out such control, it is necessary to detect the amount of knock occurrence each time the knock occurs, and to determine the amount of knock occurrence for each cylinder. However, in order to obtain the amount of knock occurrence for each occurrence of knock from the output of the integrator 7 in the conventional device described above, one operation is required, and furthermore, in order to obtain the amount of knock occurrence for each 9fcrIl, the circuit size is further increased. There was a problem that the problem was increasing and it was not easy.

This invention was made to solve the above-mentioned problems, and provides a knock control device that can easily detect the amount of each knock occurrence and easily determine the amount of knock occurrence for each cylinder. The purpose is to obtain.

[Means for solving problems]

The knock control device according to the present invention operates an integrator in correspondence with the ignition operation, reads and stores its output, and obtains a detected amount each time a knock occurs.

[For production]

The integrator in this invention outputs the detected amount of knock every time a knock occurs, and the detected amount of knock for each cylinder can be determined by simply reading this output.

〔Example〕

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

In FIG. 1, 1 to 6 and 11.12 are the same parts as shown in FIG. 7 described above, so their explanations will be omitted. 21 is the cylinder pulse generation amount that generates the cylinder pulse corresponding to the ignition operation of each cylinder of the engine, and 22 is the above gKm.
A closed circuit rate control circuit receives the pulse and outputs an ignition pulse whose open circuit rate is controlled to ensure the energization time of the ignition coil 12;
3 is a phase shifter that performs angle retard control on the ignition pulse according to the control voltage and outputs it; 24 is an integrator that receives the knock pulse from the comparator 6 and outputs an integrated voltage proportional to its time width; This is different from the integrator 7 of the conventional device shown in FIG. It is designed to reset the voltage every time there is ignition. 25 is an AD converter that converts the integrated voltage from 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 in correspondence with each cylinder; for example, the memory 27
is used to store the amount of knock occurring in one cylinder. 31
is a clock generator which generates pulses at regular intervals and inputs the pulses to the memory in order to subtract the values stored in each of the memories 27 to 30; 32 corresponds to the ignition cylinder from each output of the memories 27 to 30; A selection circuit that selects and outputs only data; 33 a reference pulse generator that generates a reference pulse corresponding to a reference cylinder among the four cylinders of the engine; This is a cylinder selection pulse generation circuit that sequentially generates cylinder selection pulses so that the operating states of the distribution port $26 and the selection circuit 32 correspond to a predetermined cylinder. 40 detects a failure such as a disconnection of the signal line between the acceleration sensor 1 and the frequency filter 2 or a short circuit to the ground, and also detects an abnormal voltage of the output of the noise level detector 5, and sends a fail signal to the integrator 24. This is a fail detection circuit that inputs a fail signal KF and also sends a fail signal KF to other fuel control devices, vehicle diagnostic devices, etc. in parallel.

2 and 3 are diagrams showing operating waveforms of each part of the figure, and each waveform with the same reference numeral as in FIGS. 9 and 10 showing the operating waveform of each part of the conventional device described above is These are the same portions as the waveforms in FIGS. 1 and 10.

First, basic operations are performed using FIGS. 2 and 3. When no engine knock occurs, the input of the comparator 602N becomes as shown in FIG. 2(d), and since there is no knock signal at A of FIG. Therefore, there is no output from the integrator 24 (FIG. 2(f)).

Therefore, there are no stored values in the memories 27 to 30, and the selected times F
Since there is no output of Is32, the input of phase shifter 23 (Fig. 2 (
There is no phase difference between g)) and the output (FIG. 2(h)), and the ignition timing is at the reference position.

Next, a case where knock occurs in the engine will be explained using FIG. 3. The double input of the comparator 6 is as shown in Fig. 3 1dl, and a knock signal appears at A in Fig. 3 (d-), so a knock pulse is output from the comparator 6 as shown in Fig. 3 (e). This pulse is integrated by an integrator 24. Here, since knock detection is performed corresponding to each cylinder, there is a phase shift v for each ignition.
! The output of the integrator 24 is reset by the output of J23. Therefore, the period from knock detection to reset,
The output of the integrator 24 is held at a constant value. These steps are performed for each ignition in the ignition cycle. This operation is different from conventional devices. The output of the integrator 24 (Wi component voltage) 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. The selection cycle ys32 is based on the cylinder selection pulse from the cylinder selection pulse generator 34, and the memory 2 corresponding to the third cylinder is
9 is selected and its output is output to the phase shifter 23. Here, since a knock 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. In FIG. 3, knocking also occurs in the next cylinder, so if it is a normal four-cylinder engine, knocking would occur in the fourth cylinder. The output of the integrator 24 in this case is selected by the distribution circuit 26 and stored in the memory 30. Then, the output of the memory 30 is selected by the selection circuit 32 and the output of the memory 30 is output to the phase shifter 2 during the ignition operation of the fourth cylinder.
3 is input.

Next, control for each cylinder will be explained in detail using the waveforms shown in FIG. 4. In the figure, (S) is a number representing the ignition cylinder, (a) is the output of the comparator 6, Ff) is the output of the integrator 24, (jl, (k), (1), and (b) are the numbers of the memory 27, respectively. ~The stored value of the memory 30, fp) is the selection circuit 32
The outputs fg) and fh) are the input and output of the phase shifter 23, respectively.

Now, as shown in FIG. 4 te+, the output of the comparator 6, '
A knock pulse appears, and the knock occurs in the 3rd cylinder, 2nd cylinder, 3rd cylinder, 4th cylinder, and 2nd cylinder in that order. These are converted into an integrated voltage by the integrator 24, and the output is as shown in FIG.
2. 3. 5 represents the detection knock level, starting with Kl, 2°, 3. seconds in order of 5, K
5 represents the loudest knock. At time t1, a knock occurs in the third cylinder, and the output of the integrator 24 becomes 5 in voltage.

This voltage 5 is converted into a digital signal by the AD converter 25 and input to the distribution circuit 26. The distribution circuit 26 selectively outputs 5 to the integrated voltage converted into a digital signal to the memory 29 at the ignition time t2 of the fourth cylinder.
2 and stored in the memory 29'. This allows memory 2
The stored value of 9 becomes 5 in voltage (Fig. 4 (1)). next,
At time t3, a knock occurs in the second cylinder, which is converted into an integrated voltage of 5 by the integrator 24, and this voltage is converted to 5 by the AD converter 25.
is converted into a digital signal, selectively input to the memory 28 by the distribution circuit 26, and stored in the memory 28 at time t4 (FIG. 4(k)). Time t4 is the ignition point of the first cylinder, after which the ignition operation of the third cylinder begins.

At this time, since 5 is stored in the voltage in the memory 29,
5 is output from the selection port @32 to the above voltage (Fig. 4 (p)
)), input to phase shift@23. This allows phase shift @2
3, the next ignition timing is at an angle θ5 corresponding to 5 to the above voltage.
f! (phase delay of the output (FIG. 4(h)) with respect to the input of the phase shifter 23 (FIG. 4(g))), and is ignited at time t5. Time t5 for retarding the angle θ5 from the reference ignition timing
Even though the engine was ignited at t6, 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 memory 29
Since 5 is already stored in the voltage, 2 is added to the voltage, and 7 is newly stored in the voltage (4th
Figure (1)). Regarding the ignition at time t7 (standard ignition timing), a knock occurs in the fourth cylinder at time t8, and the integrated voltage increases by 3.
is output. 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 delayed from the reference voltage by an angle θ5 corresponding to 5 at a time t9.
becomes. In response to the ignition at time t9, a knock occurs in the second cylinder at time tlo, and 1 is output as the integrated voltage.

This voltage is 1 at the time tll of the next ignition timing and the memory 28
The stored value in the memory 28 becomes 6 for the voltage. The ignition operation for the third cylinder starts from time tll, but since 7 is stored in the voltage in the memory 29 at this time, the next ignition timing t12 is retarded by an angle θ7 from the reference. 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 of 03 from the standard, and the next ignition timing of the second cylinder (time t14) is retarded by an angle of 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 generation type 31, the values stored in the memories 27 to 30 are subtracted at a predetermined rate to reduce each stored value, and the voltage input to the phase shifter 23 is decreased to determine the retard angle. We are trying to make it smaller and 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. 9. A more sophisticated system can be created.

Furthermore, as in the conventional device shown in FIG. 7, it is also possible to uniformly retard all cylinders by the same angle; in this case, the distribution circuit 26 and the 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, as appropriate.

The fail detection port FIs 40 generates a fail signal when the signal line connecting the acceleration sensor 1 and the frequency filter 2 is disconnected or short-circuited to the ground, etc., and the output of the acceleration sensor 1 is no longer properly input to the frequency filter 2. Output KF. 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 1 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 becomes very large, and the comparison standard cannot be used normally. It detects that it is no longer possible to output voltage and outputs a fail signal KF. The integrator 24 receives the fail signal K from the fail detection circuit 40.
When F is input, it operates independently of the signal from the comparator 6 and outputs the integrated voltage at the time of failure. Figures 5 and 6
The figure shows an example of the integrated voltage at the time of the above failure. The example in FIG. 5 basically shows the maximum integrated voltage V that the integrator 24 can output at all times. The output signal MAX is reset at the ignition timing (time indicated by symbol F) by the ignition signal output from the phase shifter 23, and is repeatedly set to zero every time the ignition occurs. In FIG. 6, the integration M24 is not reset by the ignition signal output from the phase shifter 23, and the ignition signal input to the integrator 24 is reset by the fail signal KF from the fail detection circuit 40. Just disable it. in this way,
Integral voltage V. When MAX is constantly output, voltage VMAX is stored in all of the memories 27 to 30, and
The desired fail ignition timing is set so that no knock occurs. Here, the maximum value V 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.

〔Effect of the invention〕

As described above, according to the present invention, knock occurring in the engine is detected from the output of the acceleration sensor, and the ignition timing of the engine is controlled according to the detected amount of knock, thereby suppressing the occurrence of knock in the engine. The engine's ignition timing control system, which operates efficiently at its limit, reads and resets the amount of knock detection each time ignition occurs, making it easy to adjust the amount of knock for each cylinder in proportion to the amount of knock occurring. Since the engine can be detected, all cylinders of the engine can be operated efficiently and the output of the engine can be greatly increased.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of this invention device, FIGS. 2 and 3 are operating waveform diagrams of this invention device, FIG. 4 is an operation waveform diagram for each cylinder of this invention device, and FIGS. 5 and 6 are this diagram. FIG. 7 is a block diagram of the conventional device; FIG. 8 is a frequency characteristic diagram of the acceleration sensor; FIGS. 9 and 10 are waveform diagrams of the conventional device. In the figure, 1... acceleration sensor, 6... comparator, 11...
...Switching circuit, 12...Ignition coil, 21...
- Cylinder pulse generator, 23... Phase shifter, 24... Integrator, 26... Distribution circuit, 27-30... Memory. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] (1) A knock sensor that detects engine knock information, a knock discriminator that selects knocks occurring in each cylinder of the engine based on the output of this knock sensor, and outputs an integrated voltage based on the output of this knock discriminator and responds to ignition operation. an integrator that makes the integrated voltage zero, an integrator that integrates this integrated voltage, a phase shifter that controls the phase shift of the ignition signal based on the output of this integrator, and an energization of the ignition coil corresponding to the output of this phase shifter. An ignition timing control device for an internal combustion engine, characterized by comprising an intermittent switching circuit.