JPS6160983B2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an ignition device for an internal combustion engine.

FIG. 1 is a block diagram showing an ignition system for an internal combustion engine, and numeral 1 indicates an input signal generator for determining ignition timing. This signal generating section supplies the detecting section 2 with an axle-synchronized input signal (rotation signal) obtained from, for example, a magnetic induction pickup coil. The detection section 2 shapes the input signal into a pulse, and supplies the pulse signal to the ON/OFF duty control section 3. This control section 3 allows current to flow through the ignition coil 4 for an appropriate time, so that the output transistor 5 is turned on (on) and turned off (cut off).
A signal determining the duty of the period is generated and the signal is supplied to the output circuit 6. This output circuit 6 is
The switching control of the output transistor 5 is actually performed. Constant current control circuit 7 detects the current flowing through ignition coil 4 through resistors 8 to 10, limits the collector current of output transistor 5 to a constant value, and feeds back a signal to duty control section 3 for subsequent control. 11 in FIG. 1 indicates a spark plug.

By the way, in the above-mentioned ignition system, the duty control unit 3 controls ON/OFF depending on the engine speed.
In order to perform duty control or to optimize ignition timing, it is necessary to create a voltage having a level that corresponds to the engine speed.
However, in the past, this voltage was obtained by integrating the axle synchronization input pulse, and ignition timing control, ON/OFF duty control, etc. were performed based on the integrated voltage. That is, in the conventional type, a voltage corresponding to the engine rotational speed was obtained by integrating input pulses, so the response to rotational changes was poor. In addition, since the integrated voltage simply stores input pulses, it is difficult to obtain an accurate voltage that corresponds to the engine speed.
ON/OFF duty control was difficult to perform.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to obtain a feedback circuit configuration that corrects the phase difference between the input signal obtained in accordance with the rotation of the engine and the sawtooth wave by observing the phase difference between the sawtooth wave and the input signal obtained in accordance with the rotation of the engine. The present invention aims to provide an ignition device that can eliminate the above-mentioned conventional problems by controlling ignition timing and ON/OFF duty.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the main parts of this embodiment, and the rotation signal detection section 2 obtains a pulse-like signal at intervals corresponding to the engine rotation speed of the internal combustion engine, as described above. The voltage storage section 21 is for storing a voltage at a level corresponding to the engine speed. The sawtooth wave generating section 22 generates a sawtooth wave having a period corresponding to the pulse signal and a slope corresponding to the storage voltage level of the voltage storage section 21. The comparison unit 23 compares the voltage level of the sawtooth wave with the first reference voltage every cycle of the pulsed signal, and when there is a deviation between these two voltages, the voltage storage unit 21 is adjusted according to the deviation. Change the storage voltage level. Ignition timing signal generation circuit 2
4 generates an ignition timing signal from the comparison result between the output voltage level of the sawtooth wave generator 22 and a second reference voltage (knock control signal). The sawtooth wave generating section 25 generates a sawtooth wave having a cycle corresponding to the ignition timing signal and a slope corresponding to the storage voltage level of the voltage storage section 21. The duty control section 3 includes a sawtooth wave generation section 25
The output circuit 6 is controlled based on the comparison result between the output voltage level of the output voltage level and the third reference voltage.

Fig. 3 shows the configuration shown in Fig. 2 above, in which ignition timing control and duty control can be performed in detail, and parts corresponding to Figs. Omitted. In FIG. 3, 31 is an external capacitor of the sawtooth wave generating section 22, and the sawtooth wave is obtained at the terminal A point of the capacitor 31 and becomes a non-inverting input of the comparators 32 and 33. The reference voltage of the comparator 32 is given from a reference voltage source 34, and the output of the comparator 32 becomes the input of the comparison section (phase detection section) 23. In the voltage storage section 21, a capacitor 35 stores a voltage corresponding to the engine speed. Terminal B of the capacitor 35 is connected to the sawtooth wave generator 22, and is connected to the sawtooth wave generator 22 via a switch 36 and a current source 37. It is connected to the power supply Vcc, and also the switch 38 and the current source 3.
Grounded via 9. This part of the voltage storage section 21 is shown in an equivalent circuit, and the switch 36
is closed when it is necessary to charge the capacitor 35 due to the operation of the comparator 23, and the switch 38 is closed.
is closed when it is necessary to discharge the capacitor 35 due to the operation of the comparator 23. The sawtooth wave generator 22 generates at terminal A a sawtooth wave whose slope corresponds to the voltage of the capacitor 35, and FIG. 4 shows a circuit for this purpose. That is, a current I proportional to the voltage V flows through the resistor R. FIG. 5 shows an equivalent circuit diagram of the main parts of the sawtooth wave generator 22, in which a switch 40 and a current source 41 are used to charge the capacitor 31;
2. The current source 43 is for discharging. Comparator 3
In No. 3, the knock control signal source 44 is given as a reference voltage. Here, knocking refers to the generation of a force that hinders engine rotation when the engine ignition timing is too early. This signal is set to adjust the ignition timing to an optimal delay to prevent knocking. The output of the comparator 33 becomes an input to the sawtooth wave generator 25. An equivalent circuit of the main part of this sawtooth wave generating section 25 is shown in FIG. Here switch 45,
The current source 46 is an external capacitor 4 for generating sawtooth waves.
9 for charging, switch 47, and current source 48 for discharging. The output of the sawtooth wave generating section 25 becomes one input of the comparators 50 and 51 of the duty control section 3. The other inputs of comparators 50 and 51 are provided from reference voltage sources 52 and 53. voltage source 5
The reference voltage V _th (2) of the current source 53 is variable depending on the power supply voltage, and the reference voltage V _th (3) of the current source 53 is variable depending on the engine speed. The comparator 50 is for charging/discharging switching of the sawtooth wave generator 25, and the comparator 51 is for outputting an ON/OFF duty control signal. The internal power supply circuit 54 is connected to the battery 5
Since there is noise and voltage fluctuation in the voltage of 5, this is stabilized.

FIG. 7 is a signal waveform diagram of each part of the above configuration, and the operation of this configuration will be explained below with reference to this diagram as appropriate. The rotation signal detection section 2 outputs the rotation signal shown in FIG. 7b and supplies it to the comparison section 23.
At the A end, a sawtooth wave (FIG. 7c) whose slope corresponds to the voltage at the B end shown in FIG. 7d is obtained. The comparison units 23 and 32 detect whether or not this sawtooth wave has reached the reference voltage V ₂ , that is, (V ₃ −V ₁ )/2, at the falling timing of the rotation signal. The sawtooth wave at the falling timing is the reference voltage V ₂
When the voltage has not reached (when there is a phase shift), the capacitor 35 of the voltage storage section 21 is charged. This is done by closing switch 36. On the other hand, if the sawtooth wave has already reached the reference voltage _V2 when the rotation signal falls (there is a phase shift), the capacitor 35 is discharged. This is done by closing switch 38. Here, the sawtooth wave in FIG. 7c shows the case where the capacitor 31 is charged and discharged in such a manner that the discharging current is twice the charging current. In this way, a voltage corresponding to the rotation signal can be obtained at the B end.

FIG. 14 is a specific circuit diagram of the comparator 23 that performs the above operation, in which 101 and 102 are R-S flip-flops, 103 and 104 are inverters,
105 and 106 are NOR circuits. Here, in the flip-flop 101, the sawtooth wave from the A end is V ₂
It is set at the following times and reset when the signal from the terminal falls, so a sawtooth wave is generated from the terminal at the falling edge of the signal from the terminal.
A signal corresponding to the time delayed from reaching V ₂ is output, the switch 38 is closed, and the capacitor 35 is discharged. On the other hand, the flip-flop 102 is set by the signal from the terminal, and the sawtooth waveform is generated.
It is reset when V ₂ is reached, so if the sawtooth wave reaches V ₂ later than the falling edge of the terminal signal, a signal is output from the terminal according to the delay, and switch 36 is closed. capacitor 3
5 is charged.

On the other hand, the ignition timing signal shown in FIG. 7e has the sawtooth wave of FIG. 7c at the threshold voltage V
By applying the threshold voltage _{V th} (1) obtained by cutting at V th (1) and corresponding to the knock control signal to the comparator 33, the ignition timing can be shifted by a desired angle on the engine rotation axis.
In this way, retard control according to the knock control signal becomes possible.

Further, the sawtooth wave shown in FIG. 7f starts charging and discharging according to the ignition timing signal obtained via the comparator 33 and the threshold voltage V _th (2) of the comparator 50 of the duty control section 3.
Performs ON/OFF duty control. That is, here, when the discharge level of the sawtooth wave drops below the threshold voltage V _th (3), it is forcibly made zero, and a duty control signal as shown in FIG. 7g is obtained via the comparator 51. It is supplied to the output circuit 6. FIG. 15 is a specific circuit diagram of the sawtooth wave generator 25 that performs the above operation, and 107 is a R
-S flip-flop, 108 is operational amplifier, 1
11 to 118 are transistors. Here, flip-flop 107 is reset by the ignition timing signal from terminal 9, and transistor 11
5 is turned off and transistor 118 is turned on, so capacitor 49 begins to charge. When this voltage reaches V _th (3), it is set by the signal at the terminal sent from the comparator 50, so the transistor 115 is turned on and the transistor 1 is turned on.
18 is turned off and capacitor 49 begins discharging. When this discharge progresses and drops to V _th (3), comparator 5
1 outputs an ON state output (see Figure 7g). Note that the sawtooth wave charging/discharging currents i ₃ and i ₂ are in a proportional relationship to the B-terminal voltage of the voltage storage section 21 . Further, the threshold voltage V _th (3) is also proportional to the B-terminal voltage, and the threshold voltage V _th (2) changes in accordance with the power supply voltage. In this way, the output circuits 5 and 6 are driven at completely different desired timings, although in synchronization with the input signal, and current is caused to flow through the ignition coil 4 as shown in FIG. can be done. The reason why the ignition coil current is saturated is due to the action of the constant current control section 7.

Figure 8 shows how to correct the sawtooth wave and B-end voltage (voltage according to engine speed).
Figures a to d are when the B terminal voltage is low;
h indicates the case where the B terminal voltage is high. That is, if the B-terminal voltage is low, there will be a difference between the sawtooth wave generated at the A-terminal and the reference voltage _V2 , so the sawtooth wave is phased and the B-terminal voltage is charged at timing _t1 . On the other hand, if the B-terminal voltage is high, at timing _t2 , the sawtooth wave is made to stand by at voltage _V2 , and the B-terminal voltage is discharged.
Correction will be made.

FIG. 9 shows another example of how to correct the sawtooth wave and the B-end voltage, in which figures a to d are for engine acceleration, and e to h are for engine deceleration. That is, when acceleration occurs, the pulse interval becomes narrower as shown in FIG. 9b, and a phase shift occurs here. Therefore, the sawtooth wave and the B-end voltage are corrected at timing _t3 . On the other hand, in the case of deceleration, as shown in FIG. 9f, the pulse interval becomes wider and a phase shift occurs, so the sawtooth wave and the B-end voltage are corrected at timing _t4 .

Figure 10 shows how to generate the ignition timing signal.
.about.e are cases where the retard angle is small, and f to g in the figure are cases where the retard angle is large. That is, since the reference voltage V ₂ and the threshold voltage V _th (1) corresponding to the knock control signal match at the falling timing of the waveform in FIG. 10a, the falling timing of the waveform in FIG.
This coincides with the falling edge of the ignition timing waveform in Figure 0c. On the other hand, when it is desired to delay the ignition timing a little later than in the case shown in Fig. 10c, the threshold voltage V _th (1) that determines the ignition timing is set as shown in Fig. 10d.
Set slightly higher than the reference voltage _V2 . In this way, control with a small retard angle can be performed. Also, when it is desired to delay the ignition timing further than in the case shown in Fig. 10e, the threshold voltage V
Set _th (1) even higher. In this way, control with a large retard angle can be performed.

FIG. 11 shows a duty control method, and waveforms a to d in the figure are the same as those in FIG. 7.
Figures e to g are for low speeds, h to j are for medium speeds, and k to m are for high speeds. That is, in the case of low speed, as shown in FIG. 11e, the ignition timing signal interval is large, the threshold voltage V _th (3) is small, and the sawtooth wave charging/discharging current i ₃ ,
i ₂ has a gentle slope. Therefore, the ratio of the duty ON period in FIG. 11g is small. On the other hand, in the case of medium speed, the pulse interval narrows as shown in Fig. 11h, the V _th (3) level rises, and the charging/discharging currents i ₃ , i ₂
The slope of is also steeper, so the ratio of the duty ON period increases as shown in Figure 11j. Further, in the case of high speed, the pulse interval becomes narrower as shown in FIG. 11k, the V _th (3) level rises further, and the slope of the charging/discharging current becomes even steeper. Therefore, as shown in FIG. 11(m), the ratio of the duty ON period is further increased to allow a sufficient ignition coil current to flow.

FIG. 12 shows a case where the ignition coil current is controlled in accordance with the high speed of the voltage of the battery 55.
- d are the cases where the battery voltage is high, and e to h in the figure are the cases where the battery voltage is low. That is, when the battery voltage is high, the threshold voltage V _th (2) is high, it takes time to discharge to the threshold voltage V _th (3), the duty ON period is small, and the 12th
Adjust the ignition coil current as shown in Figure d. On the other hand, when the battery voltage is low, the level of V _th (2) is lowered to shorten the discharge time to the level of V _th (3), the duty ON period is increased, and the ignition coil is turned off as shown in Figure 12h. Make the current large enough.

Fig. 13 shows the action of the constant current control section 7, and Fig. 13 shows the operation of the constant current control section 7.
~j is the case where the constant current time is short. That is, when the constant current time of the ignition coil current is long, the level of V _th (2) is greatly raised to take time to charge and discharge the sawtooth wave, and the duty is made small to shorten the constant current time. On the other hand, when the constant current time is short, make sure that the level of V _th (2) does not rise too much.
In order to prevent the duty from becoming too small, constant current control is not performed too much.

The ignition device that operates as described above has the following advantages. That is, as shown in FIGS. 7 to 9, when a change occurs in the engine speed, the sawtooth wave and the voltage stored in the voltage storage section can be corrected within one cycle of the rotation signal, so the responsiveness to the rotation change is improved. becomes faster. In addition, since the voltage in the voltage storage section 21 is corrected so that the rotation signal and the sawtooth wave exactly match, a voltage corresponding to the accurate rotation speed can be obtained, which improves the accuracy of ignition timing control and duty control. . Further, by simply applying a knock control signal from the outside, an ignition timing signal corresponding to the signal can be obtained.

Note that the present invention is not limited to the above embodiments, and can be applied in various ways. For example, in the embodiment, a case has been described in which a knock control signal is given to the ignition timing signal generating circuit 24, which increases when the knock is likely to occur. It can be replaced with various control signals.

As explained above, according to the present invention, the response to changes in engine speed is fast, the ignition timing control and duty control are highly accurate, and the ignition timing signal can be generated in accordance with the knock control signal by simply applying a knock control signal or the like from the outside. Therefore, it is possible to provide an ignition device that has advantages such as the following.

[Brief explanation of the drawing]

Fig. 1 is a block diagram of the ignition system, Fig. 2 is a block diagram of an embodiment of the present invention, Fig. 3 is a circuit diagram of the ignition system embodying the same essential parts, and Figs. 4 to 6 are partially detailed views of the same configuration, Figures 7 to 13
The figure is a timing chart showing the operation of the same configuration, and FIGS. 14 and 15 are partial specific circuit diagrams of FIG. 3. DESCRIPTION OF SYMBOLS 1... Input signal generation section, 2... Rotation signal detection section, 3... Duty control section, 4... Ignition coil, 21... Voltage storage section, 22, 25... Sawtooth wave generation section, 24... Ignition timing signal generator.

Claims (1)

[Scope of Claims] 1. A rotation signal detection section that obtains a pulse-like signal at intervals corresponding to the engine rotation speed of an internal combustion engine, a voltage storage section for storing a voltage at a level corresponding to the rotation speed, and a a sawtooth wave generating section that generates a sawtooth wave having a period corresponding to the pulse signal and a slope corresponding to the voltage level of the voltage storage section; a comparison unit that compares the voltage level of the sawtooth wave with a first reference voltage and changes the voltage level of the voltage storage unit in accordance with the deviation when there is a deviation between the two voltages; An ignition device comprising: an ignition timing signal generation circuit that obtains an ignition timing signal from a comparison result with a reference voltage. 2. The ignition device according to claim 1, wherein the energization for changing the voltage level of the voltage storage section is performed via a switch connected to a current source. 3. The ignition device according to claim 1, wherein the second reference voltage is variable. 4. A rotation signal detection unit that obtains a pulse-like signal at an interval corresponding to the engine rotation speed of the internal combustion engine, a voltage storage unit for storing a voltage at a level corresponding to the rotation speed, and a period corresponding to the pulse-form signal. a first sawtooth wave generating section that generates a first sawtooth wave having a slope corresponding to the voltage level of the voltage storage section; a comparison unit that compares the voltage level of the wave with a first reference voltage and changes the voltage level of the voltage storage unit in accordance with the deviation when there is a deviation between the two voltages; Voltage level and second
a second ignition timing signal generation circuit that obtains an ignition timing signal from a comparison result with a reference voltage;
a second sawtooth wave generator that generates a sawtooth wave;
An ignition device comprising: a duty control section that controls an energization time of an ignition coil based on a comparison result between the voltage level of the second sawtooth wave and a third reference voltage. 5. Claim 4, wherein the third reference voltage changes at least in accordance with the voltage of the voltage storage section.
Ignition device as described in Section.