JPS6252134B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a knock suppressing device for an internal combustion engine.
This relates to a method of performing control based on a control amount stored in a memory.

Recently, in order to improve the efficiency (fuel efficiency) and output of internal combustion engines, knock suppressing devices that detect and suppress knocking have been actively developed and adopted.

Knotting occurs depending on many factors among the operating conditions of the internal combustion engine, such as ignition timing, intake air temperature, intake air humidity, air-fuel ratio, and combustion chamber temperature. Among these factors, knocking is actually greatly influenced by changes in intake air temperature and intake air humidity. Since the temperature and humidity of the intake air 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 knotting also changes on a yearly basis. In other words, the knocking that occurs during a short period of time under the same operating conditions is of the same degree, and there is no significant difference in the frequency of occurrence or magnitude. Therefore, the control signals required to suppress knocking that occur under the same operating conditions are almost the same over a short period of time, and in addition to basic control using these average control signals, it is necessary to carry out corrective control for variations in each knocking occurrence. By the next control,
Knocking can be sufficiently suppressed.

In view of the above characteristics of knocking, the present invention detects knocking that occurs in an internal combustion engine, generates a control signal in response to the detected force, and performs feedback control to suppress knocking under high load operating conditions. The knocking suppression signal value corresponding to the load condition and rotation speed is stored, and in addition to the control signal stored when knocking occurs, corrections are made sequentially for small level differences each time knocking occurs, in order to suppress knocking with good responsiveness. It is something to do.

Hereinafter, one embodiment of the present invention will be described based on the drawings. As mentioned above, there are many factors that cause knocking to occur, and knocking can be suppressed by controlling any of them, but in this explanation, the case of ignition timing control, which is most often put into practical use, will be explained.

In Fig. 1, 1 is an ignition signal generator that generates a reference ignition signal as the internal combustion engine rotates, and 2 is an ignition signal generator that receives the reference ignition signal from the ignition signal generator 1 and performs waveform shaping and closing angle control to obtain a desired pulse width. A waveform shaping circuit that outputs the ignition pulse. 3 is waveform shaping circuit 2
4 is an ignition coil corresponding to the ignition pulse from the phase shifter 3. A switch circuit 6 for continuing the power supply of 5 is an acceleration sensor attached to the internal combustion engine and detects the vibration acceleration of the engine. A knock detector outputs a knocking signal of a level corresponding to the intensity; 8 is a pressure sensor that detects the intake pipe pressure of the internal combustion engine and outputs a pressure signal corresponding to the pressure; 9 is the above-mentioned knock detector 7; pressure sensor 8; An AD converter 10 digitizes each output from the ignition coil 5 according to its level, a knock detector 7 and an arithmetic unit 11 which receive a voltage waveform of the drive terminal of the ignition coil 5 and generate pulses for a fixed period of time.
In the waveform shaping circuit that outputs the output to The knocking intensity is determined from the output of the knock detector 7, and a reference control signal is determined from a memory 12, which will be described later, and the control signal is output. The memory 12 is controlled by the arithmetic unit 11 and stores the reference control signal.

FIG. 2 is a reference control signal stored in the memory 12, and FIGS. 3, 4, and 5 are operational waveform diagrams of each part in FIG. 1.

First, the operation of the igniter section consisting of the ignition signal generator 1 to the ignition coil 5 will be explained. The ignition signal generator 1 generates an ignition signal as the internal combustion engine rotates,
The waveform shaping circuit 2 shapes the waveform of the ignition signal, controls the closing angle, and outputs an ignition pulse with a desired pulse width. The ignition pulse is input to the switch circuit 4 via the phase shifter 3, and the switch circuit 4 continues to supply power to the ignition coil 5 in response to the ignition pulse. An ignition voltage is generated when the power supply to the ignition coil 5 is cut off,
The internal combustion engine is ignited and operated.

The pressure sensor 8 detects the intake pipe pressure of the internal combustion engine,
A pressure signal corresponding to that pressure is output. 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 internal combustion engine. Since the intake pipe pressure of the internal combustion engine changes sensitively in response to the load state of the engine, the load state of the internal combustion engine is determined from the level of the pressure signal from the pressure sensor 8 obtained by detecting this intake pipe pressure. Can be done.

The waveform shaping circuit 10 operates in accordance with the voltage at the drive terminal of the ignition coil 5, and outputs a fixed time pulse at the ignition timing.

The acceleration sensor 6 is attached to the internal combustion engine and constantly detects vibrations of the internal combustion engine. This detection force includes a knocking component due to vibrations generated due to knocking, superimposed on a noise signal due to mechanical noise generated by engine operation (for example, a noise signal detected due to valve operation). .

The knocking detector 7 selects a knocking signal from the detected force from the acceleration detector 6, and outputs a knocking signal of a level corresponding to the knocking intensity. This knocking signal is digitized by the AD converter 9 and input to the arithmetic unit 11. Further, the output of the knock detector 7 is reset by a fixed time pulse from the waveform shaping circuit 10. The calculator 11 calculates the engine load condition from the pressure signal from the pressure sensor 8 inputted via the AD converter 9, and calculates the rotational speed of the internal combustion engine from the period of the fixed time pulse from the waveform shaping circuit 10. The operating status of the engine is determined from the Further, the occurrence of knocking is detected from the knocking signal from the knocking detector 7 inputted via the AD converter 9.

If knotting is occurring in the internal combustion engine,
The computing unit 11 determines the operating state of the internal combustion engine from the pressure signal from the pressure sensor 8 and the constant time pulse from the waveform shaping circuit 10, and correlates the knocking signal from the knocking detector 7 corresponding to the level of knocking to determine the knocking level. The knocking signal is stored in the memory 12 as a reference control signal in a loaded operating state. In each high-load operating state in which knocking occurs in the internal combustion engine, a knocking signal corresponding to the above-mentioned operating state is stored in the memory 12, and a map of reference control signals corresponding to each high-load operating state is created. .

FIG. 2 shows an example of a map of the storage states (contents of the memory 12) of the reference control signals corresponding to the above operating states. Here, the operating state is determined by the load and rotation speed of the internal combustion engine, and the rotation ranges from N ₀ to
N ₄ , the load is determined by dividing it into L ₀ to L ₄ . The stored reference control signals are, for example, V R1 for operation from load L ₀ to L 1 in the rotation speed range N ₂ to N ₃ , V _R2 for load _{L 1 to} L ₂ , and V _R2 for load L ₂ to L _3. In this case, V _R3 becomes V R3, and as the load increases, V
The values increase in the order of _R1 , _VR2 , and _VR3 .

Here, the load range in which the reference control signal is stored is limited to a high load range where knocking occurs in the internal combustion engine, and the storage capacity of the memory 12 is reduced.
The efficiency of the memory 12 is increased.

Next, explanation will be given using waveform diagrams of FIGS. 3, 4, and 5.

In the waveform diagram, A is the output of the waveform shaping circuit 2, B is the output of the knock detector 7, and C is the output of the arithmetic unit 11.
The output D indicates the output of the phase shifter 3.

FIG. 3 shows a case where no knocking occurs in the internal combustion engine.

In this case, since knocking has not occurred, there is no output from the knock detector 7 (Fig. 3B), and the arithmetic unit 1
There is also no output of 1 (Fig. 3c). Therefore, since the phase shifter 3 does not perform phase shift control, the ignition pulse (D in FIG. 3) having the same phase as the ignition pulse output from the waveform shaping circuit 2 (A in FIG. 3) is input to the switch circuit 4. be done. The switch circuit 4 continues to supply power to the ignition coil 5 in response to this ignition pulse.

As a result, the power supply to the ignition coil 5 is cut off at the reference times t ₁ and t ₂ and the ignition voltage is generated.

FIG. 4 shows a waveform diagram for an operation requiring knocking control. In this case, after the ignition at time _t3 , the operating state becomes such that knocking control is required, and the computing unit 11 receives the pressure signal level from the pressure sensor 8 input via the AD converter 9, and the waveform shaping circuit 10.
The above-mentioned operating state is determined from the cycle of the constant time pulses from , and a reference control signal V _R4 (FIG. 4C) corresponding to this operating state is read out from the memory 12 and output.
The phase shifter 3 receives this reference control signal V _R4 and generates an ignition pulse (fourth ignition pulse) that is shifted in phase by an angle _θ1 to the side of the ignition pulse (FIG. 4A) from the waveform shaping circuit 2. Figure D) is output. This ignition pulse D
Accordingly, the switch circuit 4 continues to supply power to the ignition coil 5, and from the reference time points _t4 and _t6 , the angle θ ₁
At times _t5 and _t7 , the ignition voltage is generated and the internal combustion engine is operated. As a result, the internal combustion engine is operated without knocking.

FIG. 5 shows a waveform diagram in the case where the combustion conditions between the cylinders are slightly different and the control based on the reference control signal shown in FIG. 4 is slightly insufficient.

Immediately after the ignition time _t3 , the computing unit 11 detects the load and rotation speed of the engine from the level of the pressure signal from the pressure sensor 8 and the period of the fixed time pulse from the waveform shaping circuit 10, and determines the engine load and rotation speed corresponding to these operating conditions. The reference control signal is read from the memory 12 and the control signal V
Output _R5 (Figure 5C). Receiving this control signal V _R5 , the phase shifter 3 shifts the phase of the ignition pulse (A in FIG. 5) from the waveform shaping circuit 2 by an angle θ ₂ to the side that is delayed in time by an angle θ 2. D) is output.

In response to this ignition pulse D, the switch circuit 4 supplies power to the ignition coil 5, and at time _t10 , which is delayed from the reference time _t9 , an ignition voltage is generated and the engine is operated.

However, even though the ignition is now delayed by the above-mentioned angle θ ₂ at time t ₁₀ , if the combustion condition is slightly fluctuating and a low-level knock continues to occur, the knock signal K is output from the knock detector 7. Ru. The arithmetic unit 11 receives this knock signal K and outputs a control signal V _R6 obtained by adding a correction corresponding to this level to the control signal V _R5 . As a result, the next ignition will be at an angle θ from the reference ignition timing time _t11 .
The correction is performed at time _t12 , which is delayed by _three times, 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.

By the way, the memory 12 is usually used for other purposes, and a plurality of different types of data are stored in one memory. Therefore, it is necessary to reduce the storage capacity of the memory 12 as much as possible and to design it so that it can be used with a small capacity. For this reason, as is clear from the above description of the operation, the memory 12 is operated and stored only in high-load operating conditions where knocking occurs in the engine.

That is, since knocking occurs in relation to the load state of the engine, the memory 12 limits the operation to the high load side where the engine load is higher than a predetermined value,
It reduces storage capacity and increases usage efficiency.

In the above embodiment, the actual control amount is memory 1
2, the reference control signal can be corrected in response to a large change in the knocking state of the internal combustion engine by correcting the reference control signal value in the memory 12. It is possible to make corrections for seasonal changes in knocking occurrence factors, and to store reference control signals with appropriate values. In addition, the memory 12
The initial value of the reference control signal may be a value obtained from the internal combustion engine design value and may be stored in advance, or the average value thereof may be uniformly stored, and in both cases, when the initial value is set to zero. Initial controllability can be further improved.

Further, in the above embodiment, the output of the knock detector 7 is reset at each ignition timing, but the reset is not limited to this and may be reset at the ignition timing after knocking occurs. Alternatively, it is also possible to perform correction control by adding the detection signals and detecting the amount of change when knocking occurs. In this case, it is only necessary to reset when the output reaches a predetermined value.

Furthermore, although there are many factors that cause knotting,
Among these, air-fuel ratio control using ignition timing control or fuel control as shown in the embodiment is preferable. This is because many devices related to ignition timing control and air-fuel ratio control have been put into practical use, and are not only easy to implement, but can also be implemented at low cost.

As described above, according to the present invention, the knocking signals generated due to knocking are selected from the output of the acceleration sensor that detects the vibrations of the internal combustion engine, and the knocking generation elements are controlled according to the level, thereby suppressing knocking. In the system, when the internal combustion engine is in a high load state, control signal values corresponding to the engine load, rotation speed, etc. are memorized, the operating state is detected when knocking occurs, and the control signal value corresponding to the operating state is stored. By reading out the reference control signal and controlling the knocking generation element using this reference control signal, the capacity of the storage section can be minimized and an appropriate control signal can be quickly output and controlled when knocking occurs. In addition, if there is a change in the knocking generation element, correction control corresponding to the change is added. By successive corrections, extremely appropriate knocking suppression can be achieved. Furthermore, when the above-mentioned correction amount becomes larger than a predetermined value, by correcting the reference control signal value in the memory, it is possible to always perform appropriate knocking suppression in response to large fluctuations in knocking-generating factors, which is a practical advantage. It is possible to obtain the following effects.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention;
FIG. 2 is a map diagram of the storage of reference control signals, and FIGS. 3 to 5 are operational waveform diagrams of each part of FIG. 1. In the figure, 1 is an ignition signal generator, 2 and 10 are waveform shaping circuits, 3 is a phase shifter, 4 is a switch circuit, 5 is an ignition coil, 6 is an acceleration sensor, 7 is a knock detector, 8 is a pressure sensor, 9 is an AD converter, 11 is an arithmetic unit, and 12 is a memory.

Claims (1)

[Claims] 1. A knocking generating element that controls the operating state of the internal combustion engine and is a factor in the occurrence of knocking, an acceleration sensor that detects the vibration acceleration of the internal combustion engine, and a discrimination device that removes noise signals from the output of the acceleration sensor and selects knocking signal components. means, load detection means for detecting a load condition of the internal combustion engine, rotation speed detection means for detecting the rotation speed of the internal combustion engine, and when a high load condition is detected by the load detection means, the load condition and the rotation speed are detected. storage means for storing a knocking suppression signal value corresponding to the number of revolutions detected by the number detection means; a control signal calculation means for determining a knocking suppression signal from the output of the discrimination means and the value stored in the storage means; and knocking of the control calculation means. A knock suppressing device for an internal combustion engine, comprising a control means for controlling the knocking generating element based on a suppressing signal.