JPH0361022B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to an improvement in a knock suppressing device for an internal combustion engine that can always perform appropriate knocking suppression even when there are large fluctuations in the knocking generating factors of the internal combustion engine. It is.

[Conventional technology]

Recently, in order to improve engine efficiency (fuel efficiency) and output,
Knock suppression devices that detect and suppress knocking are being actively developed and adopted. Knocking occurs depending on many factors among engine operating conditions, such as ignition timing, intake air temperature, intake air humidity, air-fuel ratio, and combustion chamber temperature. Of these elements,
In practice, knocking occurs because it is greatly affected by changes in intake air temperature and intake air humidity. Since the intake air temperature and intake air humidity change depending on the season, the state in which knocking occurs changes depending on the season. Furthermore, since the seasons change on a yearly basis, the state of occurrence of knot kings also changes on a yearly basis. In other words, the knocking that occurs in a short period of time under the same operating condition is of the same degree, and there is no significant difference in the frequency and magnitude of occurrence. Therefore, the control signal required to suppress knocking occurring under the same operating condition is approximately the same over a short period of time.

Knock suppressing devices have conventionally been used to suppress the above-mentioned knocking. This device normally utilizes a memory, in which a reference control value for suppressing knocking is stored in accordance with the operating range of the engine, and knocking is suppressed using this reference control value.

[Problem that the invention seeks to solve]

However, in recent years, the number of on-vehicle devices that use memory has increased, and there is an increasing need to use memory as effectively as possible. Depending on this need, some knock suppressing devices use small memory capacity or The extra space is used for other devices. However, as mentioned above, although this type of knock suppressing device stores the reference control value for the engine load range above a predetermined value, it still has the problem that it is still insufficient in terms of effective memory utilization. had.

This invention has been made to solve the above-mentioned problems, and it is possible to reduce the capacity of a storage means for storing a reference control value for knocking suppression, or to improve the utilization efficiency of the storage means. The purpose is to provide equipment.

[Means for solving problems]

In order to achieve such an object, the present invention includes an acceleration sensor that detects the vibration acceleration of an internal combustion engine and outputs a vibration signal, and a knocking signal that removes noise signals from this vibration signal and outputs a knocking signal at a level corresponding to the knocking intensity. A means for outputting, a detecting means for detecting a load condition of the internal combustion engine, a detecting means for detecting the rotational speed of the internal combustion engine, and a reference control value for knocking suppression corresponding to the load condition and the rotational speed are stored. The storage means includes a calculation means for outputting a control signal for knocking control from the knocking signal and the reference control value, and the storage means stores information about the knocking control signal according to the load condition and rotation speed in the operating range of the internal combustion engine. The reference control value is stored corresponding to a partial region of the determined knocking suppression region from the region where the control signal takes the maximum value, and the control signal is calculated from the knocking signal and the reference control value in this partial region. It is something.

[Effect]

In this invention, the reference control value for knocking suppression stored in the storage means is limited to the portion where knocking is likely to occur, which is determined by the load condition and rotational speed. As a result, the capacity of the storage means can be significantly reduced, and the utilization efficiency of the storage means can be improved.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of a knock suppressing device for an internal combustion engine according to the present invention. In the figure, 1 is an ignition signal generator that generates a reference ignition signal according to the rotation of the engine, and 2 receives a reference ignition signal input from this ignition signal generator 1 and performs waveform shaping and closing angle control to obtain a desired signal. ignition pulse with a pulse width of (see Figure 3A, Figure 4A, Figure 5A)
A waveform shaping circuit 3 outputs an ignition pulse inputted from the waveform shaping circuit 2, and 3 is an ignition pulse whose phase is shifted to the delayed side in time according to a control signal from an arithmetic unit, which will be described later. Figure 4D, Figure 5D
4 is a switch circuit that cuts off the power supply to the ignition coil 5 in response to the ignition pulse input from the phase shifter 3. 6 is a switch circuit attached to the engine and detects the vibration acceleration of the engine. and an acceleration sensor 7 that outputs a vibration signal.
The knocking component generated as the engine knocks is selected by the vibration signal input from the engine, and a knocking signal (third
A knock detector 8 detects the intake pipe pressure of the engine; A pressure sensor outputs a pressure signal corresponding to the pressure, and 9 is the knock detector 7.
knocking signal input from and pressure sensor 8
an AD converter that digitizes each of the pressure signals inputted from the 10 according to its level and outputs the digitized knocking signal and pressure signal;
receives the voltage at the drive terminal of the ignition coil 5,
A waveform shaping circuit is provided as a rotation speed detection means for the engine that outputs a fixed time pulse at the ignition timing, and 11 is a digitized pressure signal input from the AD converter 9 and a fixed time pulse input from the waveform shaping circuit 10. From this, the operating state of the engine is determined, and the knocking strength is determined from the digitized knocking signal input from the AD converter ₉ , and the control signal (Fig. C, Figure 4C, Figure 5C
12 is a memory that stores the reference control signal V _R shown in FIG.

The ignition signal generator 1, waveform shaping circuit 2, phase shifter 3, switch circuit 4, and ignition coil 5 constitute an igniter section. In addition, the vibration signal output from the acceleration sensor 6 includes a noise signal due to mechanical noise caused by the operation of the engine (for example, a noise signal detected due to the operation of a valve).
The knocking component due to the vibration generated due to knocking is superimposed on the knocking component. Further, FIG. 2 shows an example of the states of the reference control signals stored in the memory 12 corresponding to each operating state. Here, the operating state is determined by the load and rotational speed of the engine, and is divided into rotational speed N ₀ to N ₄ and load L ₀ to _{L 4} . Also, the stored reference control signal V _R
For example, in the case of operation from load L ₀ to load L ₁ in the range of rotation speed N ₂ to rotation speed N ₃ , the reference control signal is
V _R1 , the reference control signal V _R2 when operating from load L ₁ to load L ₂ , the reference control signal V _R3 when operating from load L ₂ to load L ₃ , and as the load increases, the reference control signal also increases. It's getting bigger. In addition, Figures 3A to 3D show the waveforms of each part in Figure 1 under operating conditions in which knocking does not occur in the engine, and Figures 4A to 4D show waveforms in operating conditions where knocking control is required. The waveforms of each part in Fig. 1 are shown, and Figs. 5A to 5D show slightly different combustion conditions between the cylinders.
The waveforms of each part of FIG. 1 are shown in an operating state in which control using the reference control signals shown in FIGS. 4A to 4D results in a slight lack of control.

FIG. 6 is a conceptual diagram showing a knocking suppression region and an operating region in which the control amount is stored in the memory 12 for explaining the present invention. Here, the curve Z _C represents a knocking suppression region, and knocking is suppressed in a region on the higher load side than the curve Z _C. Curve Z _M represents the area where knocking is likely to occur in the knocking suppression area represented by curve Z _C above, and the control amount necessary for knocking suppression is determined corresponding to the area on the high load side of curve Z _M. It is stored in the memory 12.
The memory 12 shown in FIG. 2 is provided corresponding to the region on the high load side of this curve _ZM , and the reference control amount stored is the control amount necessary for suppressing knocking in this region. By controlling based on the amount, large knocking occurring in this region can be suppressed with good responsiveness.

Next, the operation of the knock suppressing device for an internal combustion engine with the above configuration will be explained in Figs. 3A to 3D and Fig. 4A.
This will be explained with reference to FIGS. 4D and 5A to 5D. First, the ignition signal generator 1 generates an ignition signal as the engine rotates. This ignition signal is subjected to waveform shaping and circuit closing angle control by the waveform shaping circuit 2, and an ignition pulse with a predetermined pulse width is output. This ignition pulse is then input to a switch circuit 4 via a phase shifter 3. Therefore, the switch circuit 4 cuts off the power supply to the ignition coil 5 in response to the input of this ignition pulse signal. When the power supply to the ignition coil 5 is cut off, an ignition voltage is generated, the engine is ignited, and the engine is put into operation. The pressure sensor 8 detects the intake pipe pressure of the engine and outputs a pressure signal corresponding to the detected pressure. This pressure signal is digitized by the AD converter 9 and input to the calculator 11 as a signal representing the load condition of the engine. In this case, the engine intake pipe pressure sensitively responds to and changes depending on the engine load condition, so it is possible to determine the engine load condition from the level of the pressure signal from the pressure sensor 8 obtained by detecting this intake pipe pressure. can. Further, the acceleration sensor 6 detects vibration acceleration of the engine and outputs a vibration signal. Therefore, the knock detector 7 selects the knocking signal from this vibration signal and outputs the knocking signal at a level corresponding to the knocking intensity.
This knocking signal is then digitized by the AD converter 9. Therefore, the computing unit 11
calculates the load condition of the engine from the pressure signal from the pressure sensor 8 that is input via the AD converter 9, and calculates the engine rotation speed from the period of the constant time pulse input from the waveform shaping circuit 10. Knocking is detected based on the knocking signal input from the knock detector 7 which is input via the AD converter 9. If knocking is currently occurring in the engine, the computing unit 11 determines the operating state of the engine from the pressure signal and the fixed time pulse, and stores the knocking signal in the memory 12 as a reference control signal for that operating state. Similarly, in each operating state in which a knocking signal is generated in the engine, the knocking signal corresponding to each operating state is stored in the memory 12 as a reference control signal corresponding to each operating state.
A map of the reference control signal V _R shown in the figure can be created.

Next, the case where the engine is in an operating state in which knocking does not occur will be described with reference to FIGS. 3A to 3D. In this case, the output of the knocking detector 7 becomes zero as shown in FIG.
The output of is also zero as shown in FIG. 3C. As a result, phase shift control by the phase shifter 3 is not performed, so
An ignition pulse shown in FIG. 3D having the same phase as the ignition pulse output from the waveform shaping circuit 2 shown in FIG. 3A is input to the switch circuit 4. Therefore, the switch circuit 4 switches the ignition coil 5 corresponding to this ignition pulse.
Since we intermittent the power supply to the reference times t ₁ and t ₂
At this point, the power supply to the ignition coil 5 is cut off, and an ignition voltage is generated.

[] The case where the engine requires knocking control will be described with reference to FIGS. 4A to 4D. In this case, after the ignition at time _t3 , the operating state becomes such that knocking control is required, and the computing unit 11
The above operating state is determined from the pressure signal level of the pressure sensor 8 input via the AD converter 9 and the period of the constant time pulse input from the waveform shaping circuit 10, and the operating state is stored in the memory 12 as shown in FIG. 4C. The reference control signal V _R4 corresponding to the state is read out and output. Therefore, the phase shifter 3 temporally changes the phase of the ignition pulse inputted from the waveform shaping circuit 2 shown in FIG. 4A by an angle θ ₁ as shown in FIG. 4D by inputting the reference control signal V _R4 . Outputs an ignition pulse whose phase is shifted to the side that lags behind. Therefore, the switch circuit 4 intermittents the power supply to the ignition coil ₅ by inputting the ignition pulse whose phase is shifted by this angle θ 1, and the switch circuit 4 interrupts the power supply to the ignition coil 5 at the points delayed by the angle θ ₁ from the reference times t ₄ and t ₆ , respectively. At t ₅ and t ₇ the ignition voltage is developed and the engine is started. As a result, the occurrence of knocking is eliminated, and the engine can be operated without knocking.

[]If the combustion conditions between the cylinders are slightly different and control using the standard control signal shown in Figure 4C results in a slight lack of control, and low-level knocking continues to occur, the lack of control will be corrected to cause the engine to knock. A case of controlling the operating state to such an extent that no occurrence occurs will be described with reference to FIGS. 5A to 5D. First, immediately after ignition timing t ₈ , the calculator 11 calculates the engine load and rotation speed from the pressure signal level from the pressure sensor 8 input via the converter 9 and the period of the constant time pulse input from the waveform shaping circuit 10. The reference control signal corresponding to this operating state is read out from the memory 12, and the control signal V _R5 shown in FIG. 5C is output. Therefore, by inputting this control signal V _R5 , the phase shifter 3 changes the phase of the ignition pulse input from the waveform shaping circuit 2 shown in FIG.
As shown in Figure D, an ignition pulse whose phase is temporally shifted to the delayed side by an angle θ ₂ is output. Therefore, the switch circuit 4 interrupts the power supply to the ignition coil 5 by inputting the ignition pulse whose phase is shifted by this angle θ ₂ , and the ignition voltage is generated at time t ₁₀ delayed from the reference time t ₉ . The engine is operated. Here, even though the ignition was now delayed by an angle θ ₂ at time t ₁₀ ,
If the combustion condition is slightly fluctuating and low-level knocks continue to occur, the knock signal K shown in FIG. 5B is output from the knock detector 7. Therefore, the arithmetic unit 11 receives this knock signal K.
In response to this input, a control signal V _R6 which is obtained by adding a correction corresponding to this level to the control signal V _R5 is output.
As a result, the next ignition occurs at the standard ignition timing t ₁₁
Correction is performed at time _t12 , which is delayed by an angle of θ ₃ , and knocking is sufficiently suppressed. Therefore, the angle θ ₃ is larger than the angle θ ₂ , and the difference between them, that is, the variation correction angle, is (θ ₃ −θ ₂ ), which corresponds to the level of the knocking signal K.

In this way, when the actual control amount greatly changes from the reference control signal read from the memory 12 by more than a predetermined value, by correcting the reference control signal value in the memory 12, it is possible to prevent a large change in the knocking state of the engine. , the reference control signal can be corrected, the above-mentioned seasonal change in the knocking occurrence factors can be corrected, and the reference control signal with an appropriate value can be stored.

By the way, in the method described above in which the reference control amount V _R is stored in the memory 12 and knocking is suppressed based on this, the capacity of the memory 12 becomes a problem.
Knock control can be performed by dividing the area into areas where knocking is likely to occur and areas where knocking is not likely to occur, as shown below, depending on the intensity of knocking occurrence. Corresponding to the operating region where knocking is likely to occur, the control amount necessary for suppressing knocking in that region is stored in the memory 12 as described above, and this control amount is read out as appropriate and control is performed based on this. Knocking can be sufficiently suppressed in areas where knocking is likely to occur. on the other hand,
Even under conditions where knocking is likely to occur, in an operating range where only relatively small knocking occurs, the knocking signal K from the knocking detector 7 is
Since knocking can be sufficiently suppressed by control based solely on the above, there is no need to store the control amount in the memory 12 for this area. In other words, it is only necessary to store the control amount corresponding to the driving range where knocking is likely to occur, and there is no need to store the control amount corresponding to the entire knocking suppression region. It is sufficient to provide memory only for areas where this is likely to occur, and the storage capacity of the memory can be reduced. For example, if the necessary control amount is stored in memory mainly in the medium speed range of the engine where knocking is likely to occur and the output torque is greatly improved by knocking control, the memory capacity can be reduced, and a memory with a small capacity can be used. Memory utilization efficiency can be improved by using the available or surplus storage capacity for other purposes.

According to the present invention, as described above, the area in which the control amount for suppressing knocking is stored in the memory is an area where knocking is likely to occur and large knocking occurs in the knocking suppression area, and the area where the control amount is stored is necessary for the memory. The purpose is to reduce the storage capacity and use the surplus storage capacity for other purposes to improve its utilization efficiency. Note that there are many factors that cause knocking, but among these, air-fuel ratio control using ignition timing control or fuel control as shown in the embodiment is preferable. The reason for this is that many devices related to ignition timing control and air-fuel ratio control have been put into practical use.
This is not only because it is easy to implement, but also at low cost. As an example of this air-fuel ratio control, the same function can of course be achieved by increasing the amount of injection from the fuel injection device in accordance with a reference control signal corresponding to a knocking signal.

〔Effect of the invention〕

As described above, in the present invention, the storage means for storing the reference control value for knocking suppression includes the control value for the knocking suppression area determined by the load condition and the rotational speed among the operating areas of the internal combustion engine. The reference control value is stored corresponding to a partial area from the area where the signal takes the maximum value, and the control signal is calculated from the knocking signal and the reference control value in this partial area, so that the capacity of the storage means can be reduced. It is possible to provide a knock suppressing device that can be made smaller or improve the utilization efficiency of the storage means.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an embodiment of a knock suppressing device for an internal combustion engine according to the present invention, and FIG.
A diagram showing a reference control signal stored in the memory of FIG.
Figure 3A to Figure 3D, Figure 4A to Figure 4D, Figure 5
FIGS. A to 5D are diagrams showing waveforms at various parts in FIG. 1, respectively, and FIG. 6 is a conceptual diagram showing an area where knocking suppression is performed and an area where the control amount is stored in the storage means. 1...Ignition signal generator, 2...Waveform shaping circuit,
3... Phase shifter, 4... Switch circuit, 5... Ignition coil, 6... Acceleration sensor, 7... Knocking detector, 8... Load detection means, 9... AD converter, 10... Rotation Number detection means, 11... calculation means, 12... storage means. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] 1. An acceleration sensor that detects the vibration acceleration of an internal combustion engine and outputs a vibration signal, and a knocking detector that removes a noise signal from this vibration signal and outputs a knocking signal at a level corresponding to the knocking intensity. a load detection means for detecting a load condition of the internal combustion engine; a rotation speed detection means for detecting the rotation speed of the internal combustion engine; and a reference control value for knocking suppression corresponding to the load condition and the rotation speed. storage means; and arithmetic means for outputting a knocking signal control signal from the knocking signal and the reference control value, the storage means determining a knocking signal based on the operating range of the internal combustion engine depending on the load condition and rotation speed. The reference control value is stored corresponding to a partial region of the knocking suppression region from the region where the control signal takes a maximum value, and the control signal is calculated from the knocking signal and the reference control value in the partial region. Features: Knock suppression device for internal combustion engines.