JPS60111938A - Knock control apparatus - Google Patents

Abstract

PURPOSE:To obtain a multi-purpose and multifunctional knock control apparatus without increasing the number of external connection terminals, by providing a circuit capable of changing the lower or upper limit value of the output of the knock control apparatus to an output part. CONSTITUTION:Resistors R27, R24 of an atmospheric sensor output converting circuit are equal in a resistance value and, when the middle point voltage of resistor R22, R23 is set to V7, the output voltage of an atmospheric sensor to Va and the output of an operation amplifier OP7 to Vs, formulae Vs=2V7-VA, V7=(Vcc.R23)/(R22+R23) are formed and said output is inputted to the positive side input terminal of OP5 through resistors 21, 20. When the negative side input terminal voltage Vb of OP5 is higher than Vs (the output voltage VB of a knock control apparatus is higher than min. clamp voltage), the output of OP5 comes to inverse voltage with respect to a diode D5 and VB receives no influence but, when Vb is lower than Vs, VB is raised to Vs through a resistor 11. When the output of the atmospheric sensor is lowered excessively, Vs is limited in its max. value by OP4. By this mechanism, a multifunctional control apparatus is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a knock control device that controls the ignition timing of an engine immediately before the knocking generation region, and particularly relates to a knock control device that controls the ignition timing of an engine immediately before the knocking generation region, and in particular, the present invention relates to a knock control device that controls the ignition timing of an engine immediately before the knocking generation region. BACKGROUND OF THE INVENTION In a conventional knock control device of this type known from Japanese Patent Laid-Open No. 55-146270, a circuit means for limiting the minimum value or maximum value of the knock control device is provided. was connected to the input section of circuit means that generates an output voltage in response to knocking. Therefore, if the maximum or minimum limit voltage value is to be changed by another external signal, circuit means for changing the limit voltage is added. In addition, it is necessary to change the circuit at the input section of the output voltage generating circuit means in response to the knock signal, which has the disadvantage of complicating the circuit and increasing the number of parts.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multifunctional and versatile knock control device that eliminates the drawbacks of the conventional device described above, minimizes the increase in the number of parts, and the complexity and complexity of the circuit.

[Summary of the invention]

The present invention has a configuration in which the output of a circuit section that limits the minimum or maximum voltage of the output of the knock control device by an external signal is inputted to the output terminal of the knock control device, that is, the ignition timing is delayed depending on the state of occurrence of knock. The circuit that determines the angle amount, advance angle amount, etc., and the circuit that determines the maximum retard amount and minimum advance angle value based on other request signals are configured independently, simplifying the circuit configuration and improving operability. It is something.

[Embodiments of the invention]

Embodiments of the present invention will be described with reference to FIGS. 1 to 3.

FIG. 1 shows a schematic configuration of a knock control device to which the present invention is applied, and FIG. 2 is an operational waveform diagram thereof.

In these figures, a knock sensor 10 converts vibrations caused by engine knocking into electrical signals. The signal is manually input to the knock control device 100. In the knock control device 100, a band pass filter (abbreviated as BPF) 2
0, among the electrical signals from the knock sensor 10, signals in a frequency band specific to knocking are discriminated and passed. B
The output signal of the PF 20 is then branched into two systems. One of them is input as an 8IG signal to the positive input terminal of the comparator 40 as it is or via the amplifier 30 as necessary, and the other is half-wave rectified by a half-wave rectifier and then input to the integrator 6o. After integrating the pressure, the pressure is averaged at the output of the BPF 20, and then amplified by the amplifier 70 and inputted to the negative side input terminal of the comparator 40 as a BGL signal.

Here, the BGL signal serves as a comparison reference for detecting a knock signal, as shown in FIG. 2(A), and only when the SIG signal becomes higher than the BGL signal voltage by the comparator 40, The output becomes high level and it is detected that knocking has occurred in the engine.

Furthermore, a knock signal voltage conversion circuit 80. Now, this comparator 4
When the 0 output becomes no-repel, the capacitor at the output part in the knock signal voltage conversion circuit 80 is charged to increase the output voltage, and at other times, the output voltage is lowered and the voltage is adjusted according to the amount of knock occurrence. Generate Vo. (Details will be explained later).

This output voltage V.

is input to the BI igniter 200.

In the BI igniter 200, the pickup coil 120
As a result, the mechanical ignition timing of the distributor is detected, and the detection signal is input to the retard circuit 140 (FIG. 2(D)).

On the other hand, in the start circuit 140, the knock control device 100
■ Output voltage. The delay angle with respect to the mechanical ignition timing is determined by the triangular waveform V# as shown in FIG.
(Fig. 2 (E)), and the ignition coil IO
The knock control circuit in which the circuit of the present invention is used is to generate a high voltage in the secondary coil by intermittent primary current of C, and cause the spark plug to spark at the ignition timing just before the hooking region of the engine. This is an overview.

The knock signal voltage conversion circuit, which is the key point of the present invention, will be explained below with reference to FIG.

First, the configuration is as follows. The output of the comparator is connected to the pace of the transistor Tr1. The collector of the transistor Tr is connected to the inverting terminal (hereinafter referred to as negative input terminal) of the operational amplifier 0P20 via a resistor 1L4. Furthermore, the anodes of m diodes D* + Ds of the engine fCt, the cathode of the diode D1, and the resistor R3 are connected to the negative input terminal of the operational amplifier OP2.

The + side of the capacitor C1 and the cathode of the diode D2 are both connected to the output terminal of the operational amplifier OP2, and the capacitor CI and the operational amplifier OF,2 form a Miller integration circuit.

The other ends of the resistors R, 3 are connected to the resistors R11, R, 12, and the other ends of the resistors R11, R12 are connected to a constant voltage power supply V, respectively.
Connected to cc and ciND.

The output terminal of the operational amplifier OP2 is connected to the output terminal B of the knock control device via resistors R5゜R6 and 10, and at the same time, the non-1 inverting terminal (hereinafter referred to as the positive input terminal) of the operational amplifier OP1゜OF2. ).

A resistor R8°9 is connected to the positive input terminal of the operational amplifier OP2, and the other end of the resistor R8 is connected to the constant voltage power supply Vcc via a resistor R7, and the other end of R9 is connected to the arm GND.

The output terminal of the operational amplifier OPI is input to the anode of the diode D1 through the output resistor 93, and the output terminal of the operational amplifier OP3 is input to the cathode of the diode D3 through the resistor 5. It is returned to the input end.

The negative input terminals of the operational amplifiers QPI and OP3 are connected to the resistors R7, 8 and 8, respectively. lL9 is connected,
The negative input terminal of the operational amplifier OP3 and the negative input terminal of the operational amplifier OP2 are connected to a common voltage.

To explain the operation above, the positive input terminal voltage ■1 of the operational amplifier OP2 constituting the Miller integrator is connected to the resistor R1,
It becomes the midpoint voltage of 几2 and is expressed as cc-R9V1=.

R7+R8+几9 On the other hand, the negative terminal of operational amplifier OP2 is connected to capacitor C1.
Since the output voltage of OF2 is returned, the negative terminal voltage (2) becomes V2=V1.

Here, when a knock signal is detected by the comparator and a high level signal is input to the base of the -C1 transistor Trl, the transistor Tr1 becomes conductive only during that time. Flow i! -- is flowing.

By the way, one end of the resistor R3 is connected to the negative input terminal of the operational amplifier OP2, and the other end is connected to the resistor R11,
It is connected to the midpoint voltage (■) of 几12. Midpoint voltage v3
If is set to the condition of Vs:>Vz, a constant current 12 always flows through the resistance ratio 3 from the midpoint to the negative input terminal of the operational amplifier OF2 - the above two currents '1 + If the operational amplifier is assumed to have ideal characteristics, the current 12 will all flow to the capacitor C1, so the current 12 will cause the + side voltage of C1 (output of the knock control device) to fall at a constant slope, and the current 11 will decrease at a constant slope. (because v1=v2 is constant).

Incidentally, from the viewpoint of engine controllability, the above rising and descending slopes are +200 to 400 rnv/msa+ and -20
It is common to set it at around 0 to -400mv/m, resulting in the operation as shown in FIG. 2(C).

By the way, the output of the knock control device is the operational amplifier OPI
, resistor R1, R,7, 8.几9, and diode D
1 determines whether it is the upper limit value or the operational amplifier OP3. Resistor TL2. 7. 8. Its lower limit is clamped by R9 and diode D3.

The positive input terminal of the operational amplifier OPI becomes a higher voltage than the negative input terminal, the operational amplifier OPI output is at a high level, the resistance ratio is 1, and the diode D.

A current flows through the resistance ratio 4 to cancel out the current flowing through the output voltage ■. is the negative input terminal v of OPI
It does not rise above 4. Furthermore, when the output v0 becomes less than the midpoint voltage ccR9'' of R7, 几8, and 几9, the negative input terminal voltage of the operational amplifier OP3 becomes lower than the positive input terminal voltage, and the operational amplifier The OP3 output becomes a low level, and a current flows through the resistance ratio 5 and the resistor diode D3 to cancel the current i2 flowing through the resistance ratio 3, thereby increasing the output voltage ■. does not fall below the negative input terminal voltage Vt of the operational amplifier OP3.

Here, we will consider converting the circuit into a monolithic IC with respect to the knock signal voltage conversion circuit section.

Monolithic ICs (hereinafter abbreviated as MIC) have the following constraints. Firstly, the resistance accuracy will not be less than 130%, and secondly, as the number of external connection terminals increases, the MI
Since the chip area of C increases and the yield deteriorates, the number of connection terminals must be kept to the minimum necessary. Third, since the capacitor is less than a few PF, it is difficult to form it in practice.

From the above-mentioned constraint conditions, the resistance R3゜4.几7
〜几9. R11, R12 and O/Capacitor C1 are MIC
Must be installed outside.

Taking the above into consideration, when determining external connection terminals for MIC implementation, the following four points will be made regarding the knock signal voltage conversion circuit section. That is, operational amplifier OPI, 0P3 (7) Q input terminals a, c to which resistors R7, R8゜R9 are connected
, the negative input terminal d of the operational amplifier OP2 to which the resistor R3, the capacitor 4, and the capacitor C1 are connected, and the output terminal of the operational amplifier OP2 connected to the output terminal of the knock control device.

The above is a case where a knock control device having normal functions is made into a monolithic IC.

Now, let us consider a case where the lower limit value of the output voltage of the knock control device is changed as shown in FIG. 4 by the output of the atmospheric pressure sensor in contrast to the normal function.

- In this case, considering the conventional circuit system, it is easiest to change the negative input terminal voltage Vl of the operational amplifier OP3, which clamps the lower limit of the output voltage. but,
Since the voltage Vl is also connected to the positive input terminal of the operational amplifier OP2, when Vl is changed during knock control, the negative input terminal voltage V2 of the operational amplifier OP2 changes in conjunction with the change.
As a result, the output terminal voltage, that is, the output voltage Vo of the knock control device itself is interlocked with each other, so that the desired function cannot be obtained. Therefore, in the conventional circuit system, it is necessary to disconnect the positive side inlet terminal of the operational amplifier OP2 from Vl and add one new external connection terminal for the MIC.

The aim of the invention is to eliminate this drawback. That is, the configuration is such that a resistance ratio 6 is connected to the output terminal of the MIC, and a resistor RIO is further connected to the other end of the resistor R6 to serve as the output terminal of the knock control device.

On the other hand, the connection point between resistor R6 and resistor 1 (, 10) is connected to the output terminal of operational amplifier OP5, which is the output section of the output minimum voltage variable circuit, with a resistance ratio of 19. Connect the negative input terminal.The positive input terminal of the operational amplifier OP5 is connected to the
The anode of the diode D4 is connected through a resistor R, 18 connected to the negative input terminal of the operational amplifier OP4 and the output terminal of the operational amplifier 4, which limits the maximum value of the output of the output minimum voltage variable circuit, and the resistor R20 is also connected. .

At the other end of the resistance ratio 20, a resistor was provided for receiving the output of the atmospheric pressure sensor and converting it into the minimum limit voltage of the knock control device.
Resistor R21 to R25, 27, tuner diode ZD
2. Connect the atmospheric pressure sensor output conversion circuit consisting of capacitor c3 and operator 77'OP7.

Further connected is a starting compensation circuit comprising an operational amplifier OP6 and a diode D6, which are provided to clamp the output of the knock control device to a predetermined voltage when the engine is started.

The operation in the above configuration is as follows.

The resistance I (, 27 and 几24) of the atmospheric sensor output conversion circuit
The constant is R27 - 24, and the resistance ratio is 22. The midpoint voltage of 几23 is 7, the output voltage of the atmospheric pressure sensor is VA, and the output terminal voltage of operational amplifier OP7 is v8 and 1 (21, R20
The signal is input to the positive 111 input terminal of the operational amplifier OP 5 (7) through the OP 5 (7).

Here, if the output voltage of MIC, that is, the negative input terminal voltage of OF2, is higher than voltage ■8 (if the output voltage of the knock control device is controlled at a voltage higher than the minimum clamp voltage), OI) Although the 50 output becomes a low level, it becomes a reverse voltage to the diode D5 connected to the output terminal via the resistor R19, so it does not affect the output voltage Vm of the knock control circuit, but Vb When V8 is lower than V8, the output of the operational amplifier OP5 becomes a high level and becomes the forward voltage of the diode D, so current is supplied through the resistor R11 and the output Vn of the knock control device is pulled up to the voltage V8.

Therefore, the output of the knock control device is not affected by the output of the atmospheric pressure sensor during control, but the minimum clamp voltage changes depending on the output of the atmospheric sensor.

If the output of the atmospheric pressure sensor drops too much due to some condition, the stain pressure v8 will increase in both types, but it is clear that increasing this value indefinitely will have a negative effect on the engine. As a countermeasure against this, the maximum value is limited by the operational amplifier OP4. In other words, since the voltage V8 is input to the negative input terminal of the operational amplifier OP4, when the positive input terminal voltage becomes higher than the voltage ■5, the output terminal of the operational amplifier OP4 becomes low level through the diode D4 and the resistance ratio 18. Current flows and the resistance ratio is 21. Due to the voltage drop across R22, VB is limited to the voltage V6 at the positive input terminal of operational amplifier OP5.

In addition, operational amplifier OP6 is used when starting the engine (3501-
(Below) A high level signal is input from the rotation detector, and the output of the operational amplifier OP6 becomes high level, and current is supplied via the diode D6, so the voltage v+I limited by the operational amplifier OP4 is output from OF2.

When starting the engine, as detailed in Japanese Patent Application No. 57-46555, the knock control output terminal voltage Vb of the MIC is clamped to ■l, so the voltage Vm of the output groove B is the IE voltage ■5. be clamped to.

Also, if the atmospheric pressure sensor output Va is too high for some reason, the output terminal voltage of operational amplifier 01) 5 will be 0■
However, in any case, the output terminal voltage of the MIC does not fall below the minimum clamp voltage as described above, and therefore, for the reason described above, the knock control output Vm has a minimum value of 1.

As described in detail above, according to the present invention, by installing the minimum limit voltage variable circuit in the output section, the minimum clamp voltage can be controlled by the knock control device while minimizing the number of terminals for external reading of the MIC. It can be freely varied without impairing the original controllability. Furthermore, by reversing the polarity of the diode D5, it is also possible to create a configuration in which only the maximum voltage can be freely varied.

The above is a detailed explanation of the case where the knock control device is made into an MIC, but the above also applies when attempting to forcibly change the minimum or maximum output voltage of the knock control device from outside. .

In other words, the conventional circuit (with 117 configurations, the minimum voltage from the outside, -
Alternatively, if the maximum voltage is changed to a value other than the clamp voltage of the knock control device itself, it is necessary to provide a new terminal for connection to the outside from the negative input terminal of the operational amplifier OP3, and the Sharing is the power of sharing. In the present invention, the above-mentioned drawbacks can be overcome because the above-mentioned functions are obtained by connecting a separate circuit to the output terminal section of the knock control device.

〔Effect of the invention〕

According to the present invention, since the circuit for varying the lower limit or upper limit of the output of the knock control device is attached to the output terminal section, a versatile and multifunctional knock control device can be realized without increasing the number of external connection terminals. .

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a knock control device to which the present invention is applied, FIG. 2 is an operating waveform diagram thereof, FIG. 3 is a circuit diagram showing details of a knock signal voltage conversion circuit, and FIG. FIG. 3 is a diagram showing the relationship between the minimum clamp output voltage and the atmospheric pressure sensor output voltage.

Claims (1)

[Claims] 1. In a knock control device that serves as a first circuit means for detecting knocking occurring in an internal combustion engine and generating an output voltage according to the state of occurrence of knocking, the minimum value of the output voltage of the first circuit means or A second circuit means for changing the maximum value according to another external signal is provided, and the output of the second circuit means is applied to the output section of the first circuit means. Knock control device.