JPH0366507B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition timing control device for an internal combustion engine that controls knocking in the internal combustion engine.

[Conventional technology]

It is desirable to set the ignition timing of an internal combustion engine in a manner that will give the best efficiency for the engine's operating conditions.
It is desirable to set the ignition timing to be advanced so that it approaches the torque.

However, excessive advance of the ignition timing causes excessive knocking, which not only reduces operating efficiency but also causes damage to the engine.

Therefore, it is necessary to have an ignition timing control device that controls the ignition timing to the optimum by setting the standard ignition advance characteristic in advance to the advance side in order to bring it closer to MBT, and then performing timely retard control in response to the occurrence of knocking. Become.

The conventional ignition timing control device for an internal combustion engine shown in FIG. 6 will be described below. Reference numeral 1 in FIG. 6 is an acceleration sensor that is attached to the engine and detects the vibration acceleration of the engine, and 2 is a frequency filter that passes signal components of frequencies that are highly sensitive to knocking out of the output signal of the acceleration sensor 1.

Of the output signal of the frequency filter 2, the analog gate 3 blocks out noise that becomes an interference wave for the knock detection. A gate timing controller 4 instructs the analog gate 3 to open or close in response to the timing of occurrence of this disturbing noise.

Further, the noise level detector 5 detects the level of mechanical vibration noise of the engine other than knocking and outputs it to the comparator 6. This comparator 6 compares the output voltage of the analog gate 3 and the output voltage of the noise level detector 5, generates a knock detection pulse, and outputs it to the integrator 7.

The integrator 7 integrates the output pulses of the comparator 6, generates an integrated voltage corresponding to the knocking intensity, and outputs it to the phase shifter 8. The phase shifter 8 shifts the position of the reference ignition signal in accordance with the output voltage of the integrator 7.

On the other hand, the rotation signal generator 9 generates an ignition signal according to a preset ignition advance characteristic and outputs it to the waveform shaping circuit 10. The waveform shaping circuit 10 shapes the waveform of the output of the rotational signal generator 9, and at the same time controls the closing angle of the energization of the ignition coil 12.

Further, the output of the phase shifter 8 is inputted to a switching circuit 11, and this switching circuit 11 switches on/off the power supply to the ignition coil 12 based on the output signal of the phase shifter 8.

Note that the fail-safe circuit 13 detects an abnormality in the vibration acceleration detection system, and its output is sent to the integrator 7.

FIG. 7 shows the frequency characteristics of the output signal of the acceleration sensor 1. In FIG. 7, A shows the case where there is no knocking, and B shows the case where knocking occurs.

The output signal of the acceleration sensor 1 includes a knock signal (a signal generated due to knocking), mechanical noise from other engines, and various noise components on the signal transmission path, such as ignition noise. Comparing A and B in FIG. 7, it can be seen that the knock signal has unique frequency characteristics.

Although this distribution differs depending on the engine or the mounting position of the acceleration sensor 1, there is a clear difference in the distribution depending on the presence or absence of knocking in each case.

Therefore, by passing the frequency component of this knock signal, the noise of other frequency components can be suppressed, and the knock signal can be detected efficiently.

Figures 8 and 9 show the operating waveforms of each part in Figure 6, and the same symbols indicate the waveforms of the same parts. Figure 8 shows the mode in which engine knocking does not occur, and Figure 9 Indicates the mode in which engine knocking is occurring.

Next, the operation of the ignition timing control device for an internal combustion engine shown in FIG. 6 will be explained. The ignition signal generated by the rotation signal generator 9 in accordance with the ignition timing characteristics set in advance by the rotation of the engine is waveform-shaped by the waveform shaping circuit 10 into opening/closing pulses having a desired closing angle. drives the switching circuit 11 via
The engine is ignited and operated by the ignition voltage of the ignition coil 12 that is generated when the power supply to the ignition coil 12 is interrupted and the energizing current 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 may contain mechanical noise or ignition noise, as shown in Figure 8a. At time F, ignition noise occurs on the signal transmission path.

By passing this signal through the frequency filter 2, the mechanical noise component is considerably suppressed as shown in Figure 8b, but the ignition noise component is strong and is output at a high level even after passing through the frequency filter 2. may be done. If this continues, the ignition noise will be mistakenly recognized as a knock signal, so the analog gate 3 adjusts the ignition timing based on the output of the gate timing controller 4 (FIG. 8c), which is triggered by the output of the phase shifter 8. The gate is closed for a period of time to block ignition noise. For this reason, only the low-level mechanical noise remains in the output of the analog gate 3, as shown in FIG. 8d (a).

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 (FIG. 8d, b).

Therefore, as shown in FIG. 8d, the output of the noise level detector 5 is larger than the average peak value of the output signal of the analog gate 3, so the output of the comparator 6 for comparing these is as shown in FIG. Nothing is output as shown in e, and all noise signals are eventually removed.

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

Therefore, the opening/closing 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 is the same as the reference ignition timing. Become.

Furthermore, when knocking occurs, the output of the acceleration sensor 1 includes a knocking signal around a certain time delay from the ignition timing as shown in FIG. 9a, and the signal after passing through the frequency filter 2 and analog gate 3 is As shown in Fig. 9(d), the knock signal is largely superimposed on the mechanical noise.

Among the signals passed through the analog gate 3, the rise of the knock signal is steep, so that 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 comparator 6 become A and B as shown in FIG. 9d, respectively, so that a pulse is generated at the output of the comparator 6 as shown in FIG. 9e.

An integrator 7 integrates the pulses and generates an integrated voltage as shown in FIG. 9f. Since the phase shifter 8 shifts the phase of the output signal of the waveform shaping circuit 10 {Fig. 9g (reference ignition signal)} to the delayed side in time according to the output voltage of the integrator 7, the phase shifter 8 The phase of the output of the switching circuit 11 lags behind the phase of the reference ignition signal of the waveform shaping circuit 10, and the phase is shown in FIG. 9h.
to drive.

As a result, the ignition timing is delayed and knocking is suppressed. Eventually, the conditions shown in FIGS. 8 and 9 are repeated to achieve optimal ignition timing control.

On the other hand, if an abnormality occurs in the acceleration sensor 1 or in the signal line installed between the acceleration sensor 1 and the frequency filter 2, it becomes impossible to detect the knock signal and control the ignition timing. The outbreak becomes excessive,
There is a risk of damage to the engine.

For this reason, a fail-safe circuit 13 is provided, which operates the integrator 7 and sets the ignition timing to a predetermined angular position on the retarded side, thereby controlling the knocking that occurs in the engine to a slight level. , protect institutions.

[Problems to be Solved by the Invention] In the conventional device shown in FIG. 6, the integrator 7 receives the output of the comparator 6 for transmitting the detected knock signal and the output of the fail-safe circuit 13 for detecting phenol. is entered. In addition, the acceleration sensor 1 to the comparator 6 and the failsafe circuit 13
constitutes a knock detection section 101, and the integrator 7 to ignition coil 12 constitute an igniter section.

With the recent trend toward higher quality and electronic control, system configurations have become more diverse and complex, and it may be desirable to have a system configuration in which the output of the comparator 6 and the input of the integrator 7 are divided into blocks.

For example, if the igniter circuit section 102 excluding the rotation signal generator 9, the switching circuit 11, and the ignition coil 12 is integrated with the fuel control function, and the engine is centrally controlled in a comprehensive manner, the control is performed using a computer. In this case, the computer circuit including the igniter circuit section 102 may be installed inside the vehicle due to reliability such as heat resistance, while the knock detection section 101 may be installed inside the engine compartment in which the engine is mounted.

Another reason for this configuration is that the acceleration sensor 1 is a weak analog signal that is relatively susceptible to noise.
It may be preferable to transmit the output of the comparator 6, which is a pulse signal that is resistant to noise, rather than transmitting the output of the comparator 6 for a long time.

In such a case, the signal lines connecting the comparator 6 and the fail-safe circuit 13 and the integrator 7 become very long, so it is desirable to reduce the number of signal lines.

In addition, in such a case, the knock detection section (comparator 6
A connector for signal line relay is also interposed between the output of the fail-safe circuit 13) and the igniter section (input of the integrator 7), and an abnormal state of this signal line (for example, a disconnection of the signal line) Detection and appropriate control are important issues for system reliability.

This invention was made to solve these problems, and reduces the number of signal lines between the comparator, the fail-safe circuit, and the integrator to improve reliability.
It is an object of the present invention to provide an ignition timing control device for an internal combustion engine that easily detects and controls failures due to disconnection of the signal line.

[Means for solving problems]

The ignition timing control device for an internal combustion engine according to the present invention includes a transmission means that receives a knock signal and a fail signal and outputs the signal through one signal line, and an output of the transmission means that receives the knock signal, the fail signal, and the signal line. a discriminating means for discriminating the disconnection of the wire; a phase shifting means that receives the output of the transmission means and the output of the discriminating means and changes the phase of the reference ignition timing signal according to the input of the knock signal and the input of the fail signal or the disconnection signal; It was established.

[Effect]

In this invention, the operating modes of the comparator and the fail-safe circuit are the same, and the stable state voltage levels of these output signals are set in the comparator and the knock detection section, and the knock signal and fail signal are combined. The signal is transmitted as one signal through one signal line, and if this signal line is disconnected, it is detected on the igniter side.

〔Example〕

Embodiments of the ignition timing control device for an internal combustion engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of one embodiment.
In FIG. 1, parts that are the same as those in FIG. 6 are given the same reference numerals, and their explanation will be omitted, and the parts that are different from those in FIG. 6 will be mainly described.

As is clear from comparing FIG. 1 with FIG. 6, in FIG. 1, the knock detection section 101 has an OR circuit 21 added to the structure of FIG. 6. This OR circuit 21 outputs a logical sum signal of signals obtained by inverting the phase of the input signal to the integrator 7 and filter 31 of the igniter circuit section 102.

This filter 31 receives the knock signal E _a-1 in Fig. 4a.
does not respond to the output V, maintains its output V, and outputs the fourth
In response to the signals E _a-2 and E _a-3 in FIGS. b and 4 c, the output is made zero.

The output of this filter 31 is sent to a voltage determiner 32. The voltage determiner 32 determines whether the output of the filter 31 is zero, and when it is zero, outputs a fail signal to operate the integrator 7. The other parts are constructed in the same manner as in FIG.

The OR circuit 21 is constructed as shown in FIG. In FIG. 2, the left side of the dashed line represents the knock detection section 101, and the right side represents the igniter circuit 102, and the OR signal of the respective outputs of the comparator 6 and the fail-safe circuit 13 is input to the base of the transistor 41. It's becoming like that.

The emitter of the transistor 41 is grounded, and the power supply voltage V is applied to the collector through a resistor 42. From this collector, the igniter circuit section 1
The signal E _a is sent to 02.

Further, FIG. 3 shows another example of the OR circuit 21 in FIG. 1. The output of the comparator 6 and the fail-safe circuit 1 are connected to the base of the transistor 43.
A logical OR signal with the output of 3 is inputted.

The emitter of this transistor 43 is grounded, the collector is grounded via a resistor 45, and a power supply voltage V is applied via a resistor 44, so that an output E _b is produced.

In the case of this FIG. 3, the igniter circuit section 102
The power supply voltage V is divided by the resistor 44 on the igniter circuit section 102 side and the resistor 45 on the knock detection section 101 side, and the voltage at the middle point is outputted to the integrator 7 and filter 31 of the igniter circuit section 102 as E _b . , shows an example in which a transistor 43 is connected in parallel with the resistor 45 of the knock detection section 101.

Next, the operation of this invention will be explained. First, referring to FIG. 2, a case will be described in which a knock signal and a fail signal are transmitted from the knock detection section 101 to the igniter circuit section 102. In addition,
When explaining the operation, explanation of the same parts as in FIG. 6 will be omitted.

This figure 2 shows the power supply voltage V of the knock detection section 101.
This shows a case where the signal E _a is transmitted from the transistor 41 to the igniter circuit section 102 via the resistor 42 . When the transistor 41 is on, the signal E _a is zero, and when the transistor 41 is off, the signal E _a is V. Therefore, in FIG. 2, the transistor 41 is turned on when a knock is detected, and the signal E _a =E _a-1 at this time changes from V to zero.

Further, when a fail is detected, the transistor 41 is continuously turned on, and in this case, the signal E _a =E _a-2 is continuously zero. Then, a knock detector 101 and an igniter circuit section 102 transmitting this signal E _a
If the signal line between is disconnected, the signal E _a in this case
=E _a-3 becomes a continuous state of zero.

That is, the signal E _a transmitted to the igniter circuit section 102 momentarily changes from V to zero when the knock signal is output, and when the fail signal is output and the knock detection section 10
When this signal line installed between the signal line 1 and the igniter circuit section 102 is disconnected, it becomes a continuous state of zero.

On the other hand, in the case of FIG. 3, the transistor 43 is turned on when a knock is detected, and at this time the signal E _b =E _b-1
Figure a) goes from 1/2V to zero.

Furthermore, when a fail is detected, the transistor 43 remains on, and in this case E _b = E _b-2 (Fig. 5b)
becomes a continuous state of zero. If the signal line between the knock detection unit 101 and the igniter circuit unit 102 that transmits this signal E _b is disconnected, the signal in this case
E _b = E _b-3 (Figure 5c) becomes V. In the case of this FIG. 3, unlike the case of FIG. 2 above, the input voltage E _b of the igniter circuit section 102 is as shown in FIGS.
As shown in , there are three voltage forms: E _b-1 , E _b-2 , and E _b-3 .

As described above, the signal transmitted to the igniter circuit section 102 is clearly defined in the case where the knock signal is transmitted in the normal state, the case where the fail signal is transmitted, or the signal line for this transmission is disconnected. Since the signals are different from each other, the igniter circuit section 102
The side determines these transmission signals and outputs a knock signal,
It is possible to easily detect a fail signal or a break in this signal line.

Next, the operation shown in FIG. 1 will be explained. Knock signal at the output of the OR circuit 21 (signal in Fig. 4 a)
Since E _a-1 ) is output like a burst signal as shown in Figure 9 e (the signal phases are opposite in Figure 9 and Figure 4), the signal E a in Figure 4 _{a -1} is a signal that takes the voltage V as a steady value and becomes zero when a knock is detected.

On the other hand, when the fail signal (signal E _a-2 in FIG. 4b) and the signal line for transmitting these signals from the knock detection section 101 to the igniter circuit section 102 are disconnected (signal E _a-3 in FIG. 4c) ) has a signal value of zero.

Since the filter 31 does not respond to high frequencies for each of the above-mentioned signals E _a-1 , E _{a-2 ,} and E _a-3 , its output voltage is V, and its output voltage becomes zero when the fail signal (E _a-2 ) and the signal line are disconnected.

The voltage determiner 32 receives the output voltage of the filter 31, and determines that if the voltage is V, it is a normal state, and if the voltage is zero, it is an abnormal state. Therefore, when the input signal of the filter 31 is the above-mentioned signal E _a-2 or E _a-3 , the output voltage of the filter 31 becomes zero, and the voltage judger 32 detects that the input voltage becomes zero. ,
The fail signal is input to the integrator 7.

When the fail signal is not input from the voltage determiner 32, the integrator 7 outputs a control voltage according to the input knock signal (E _a-1 ).

On the other hand, when the fail signal is input, its output is set to a predetermined fixed voltage, and the ignition timing is set to a predetermined angular position that does not cause knocking that is harmful to the engine by the phase shifter 8, so that the engine is protected. Ru.

In the above, the signal transmission from the knock detection section 101 to the igniter circuit section 102 was performed using the circuit shown in FIG. 2, but as mentioned above, the circuit shown in FIG. , a fail signal and a disconnection of the signal transmission line can be detected by simple voltage comparison.

Further, it is also possible to detect whether the igniter is normal or abnormal by measuring the pulse width. That is,
The pulse width of the knock signal can be limited by the characteristics of the frequency filter 2. For example, if it is a bandpass filter with a center frequency f ₀ , the maximum pulse width of the knock signal is 1/2·f ₀ (Fig. 9d). (This is clear from the knock signal detection operation of the comparator 6 shown in FIG.

〔Effect of the invention〕

As explained above, this invention is an ignition system that detects knocking information of an engine and retards the ignition timing according to the detected strength to suppress knocking. Since the signal is transmitted through a single signal line and the fail function is activated when this signal line is disconnected, the signal wiring can be reduced and the ignition timing can be set to protect the engine in fail mode even when the signal line is disconnected. The practical effect of being able to do this can be obtained.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the ignition timing control device for an internal combustion engine according to the present invention, and FIGS. 2 and 3 show specific configurations of the OR circuit in the ignition timing control device for the internal combustion engine, respectively. Figure 4 is a diagram showing the output signal of the OR circuit in Figure 3, Figure 5 is a diagram showing the output signal of the OR circuit in Figure 3, Figure 6 is the ignition timing of a conventional internal combustion engine. A block diagram of the control device, FIG. 7 is a diagram showing the output of an acceleration sensor in a conventional ignition timing control device for an internal combustion engine, and FIGS. 8 and 9 respectively explain the operation of the conventional ignition timing control device for an internal combustion engine. It is a waveform diagram of each part for doing. 1... Acceleration sensor, 2... Frequency filter,
5...Noise level detector, 6...Comparator, 7...
... Integrator, 8 ... Phase shifter, 9 ... Rotation signal generator, 10 ... Waveform shaping circuit, 11 ... Switch circuit, 12 ... Ignition coil, 13 ... Fail-safe circuit, 21 ... OR circuit , 31...filter,
32...Voltage judger, 101...Knock detector,
102...Igniter circuit section. Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. An acceleration sensor that detects a knock information signal of an internal combustion engine, a discrimination means that removes a noise signal component from the output of this acceleration sensor and outputs a knock signal corresponding to knocking occurring in the engine, and detects an abnormality of the acceleration sensor and detects a failure. A fail detection means for outputting a signal; a transmission means for receiving the knock signal and the fail signal; and a transmission means for outputting through a single signal line; receiving the output of the transmission means, and determining whether the knock signal, the fail signal, or the signal line is disconnected; a reference ignition timing signal generation means for generating a reference ignition timing signal; the output of the transmission means and the output of the discrimination means are input; the phase of the reference ignition timing signal is changed in accordance with the input knock signal; , a phase shifting means for changing the phase of the reference ignition timing signal even in the fail mode when a fail signal or a disconnection signal is input, and a switching means for intermittent power supply to the ignition coil in response to the output of the phase shifting means. An ignition timing control device for an internal combustion engine, characterized by: