JPS62354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine ignition timing control device that controls ignition timing according to the engine rotational speed, and particularly to one that calculates and controls the ignition timing according to the engine rotational speed. An ignition timing control device for an engine that can obtain the ignition timing and retard angle according to the rotation range and set the ignition timing to optimize the engine output from low speed to high speed without complicating the retard circuit. The purpose is to provide.

Embodiments of the ignition timing control device for an engine according to the present invention will be described below with reference to the drawings. FIG. 1 is a circuit diagram showing the configuration of one embodiment. This first
In the figure, block [ ] is an ignition device, which takes a known CDI ignition circuit as an example, and has the following configuration. That is, 1 is a generating coil of a magnet generator, which generates positive and negative alternating current outputs in synchronization with the rotation of the engine.
A diode 2 half-wave rectifies the positive wave output from the power generating coil 1, and a diode 3 short-circuits the negative wave. Diode 3 is generator coil 1
is connected in parallel with the generator coil 1, one end of which is grounded, and the other end of which is the diode 2, capacitor 4,
It is grounded via the primary coil 5a of the ignition coil 5. One end of each of the secondary coil 5b and the primary coil 5a of the ignition coil 5 is connected in common, and the other end of the secondary coil 5b is grounded via the ignition plug 6. The cathode of the diode 2 is grounded via a thyristor 7, and a resistor is connected between the gate and cathode of the thyristor 7.

The capacitor 4 is charged by the rectified output of the diode 2, and the primary coil 5a of the ignition coil 5 and the thyristor 7 form a discharge circuit for the capacitor 4. That is, when the thyristor 7 is conductive, the charge in the capacitor 4 generates a high voltage in the primary coil 5b.

PROT [ ] is an ignition timing control circuit and has the following configuration. That is, 8 is a signal coil for detecting the ignition position, which generates positive and negative voltages in synchronization with the rotation of the engine, and outputs from diodes 9, 10, 11, 1.
As described later, one voltage (lag side) is directly applied to the gate of the thyristor 7 to drive the thyristor 7, and the other voltage (lead side) is applied to a flip-flop circuit (hereinafter referred to as FF circuit). It is connected to the set input terminal (S terminal) of 13 (referred to as ).

Note that the voltage generated by the signal coil 8 is configured to be generated with a predetermined crank angle difference between the leading side and the lagging side, and this angular difference is mechanically set and always constant.

14 is a resistor, 15 is a capacitor, and 16 is an operational amplifier (hereinafter referred to as an operational amplifier), and these three constitute an integrator. That is, operational amplifier 16
A resistor 14 is connected between the inverting input terminal of FF13 and the output terminal Q of FF13.
A capacitor 15 is connected between the output terminal and the inverting input terminal of this operational amplifier 16. The reference voltage is applied to the non-inverting input terminal of the operational amplifier 16.
V ₁ is applied.

The output terminal of the operational amplifier 16 is connected to the inverting input terminal of the comparator 17. Comparator 17
A reference voltage V ₂ is applied to the non-inverting input terminal of. The output terminal of this comparator 17 is connected to the reset input terminal R of the FF 13.

Further, the output terminal of the operational amplifier 16 is connected to the inverting input terminal of the comparator 18. A voltage V _G is applied to the non-inverting input terminal of this comparator 18 . The output terminal of this comparator 18 is connected to the input terminal of block [ ]. This block [] has capacitor 19 and diode 2
This is a differentiator circuit consisting of 0 and detects the rising edge of a pulse.

Block [ ] is a rotation speed/voltage converter (hereinafter referred to as FV circuit) and is constructed as follows. 21 is a resistor, 22 is a capacitor, and 23 is a diode, these three constitute a differential circuit, and F・F
A signal synchronized with the rotation is obtained from the output terminal Q of the circuit 13, and a pulse proportional to the rotation speed and a fixed amount per pulse is obtained by this differentiation circuit. The output of the differentiating circuit is applied to the inverting input terminal of an operational amplifier 26 via a diode 24 and a resistor 25.

A non-inverting input terminal of this operational amplifier 26 is grounded, and a capacitor 27 is connected between the output terminal and the inverting input terminal. This operational amplifier 26 has a resistor 2
5. Together with the capacitor 27, it constitutes an integrator, and this integrator obtains a voltage at the output end of the operational amplifier 26 that increases in proportion to the rotation speed.

The output end of the operational amplifier 26 is applied to the inverting input end (one end) of the operational amplifier 29 via a resistor 28. A resistor 30 is connected between the inverting input terminal and the output terminal of the operational amplifier 29, and a bias voltage V ₃ is applied to the non-inverting input terminal. This operational amplifier 29 forms a voltage inversion circuit together with resistors 30 and 28, and the output voltage of the operational amplifier 29 remains constant until the output voltage of the operational amplifier 26 exceeds the bias voltage _V3 applied to the non-inverting input terminal of the operational amplifier 29. As the output voltage of the operational amplifier 26 becomes higher than the bias voltage _V3 , the output voltage of the operational amplifier 29 decreases in proportion to the input voltage.

The output terminal of the operational amplifier 29 is connected to the non-inverting input terminal of the operational amplifier 31.
A voltage V ₄ is applied to the inverting input terminal of the circuit 1 via a resistor 34 . A capacitor 32 is connected between the inverting input terminal and the output terminal, and a diode 33 is connected between the output terminal of the operational amplifier 31 and the inverting input terminal of the operational amplifier 29.

The circuit consisting of the operational amplifier 31, the capacitor 32, the diode 33, and the resistor 34 is an F-V limiting circuit, which receives the output voltage of the operational amplifier 29, and if the output of the operational amplifier 29 falls below a certain value, the voltage at the output terminal of the operational amplifier 31 is reduced. is lower than the input voltage of the operational amplifier 29, and the output voltage of the operational amplifier 29 is kept at a constant value.

That is, the circuit including the operational amplifier 29 is an inverting amplifier, and the circuit including the operational amplifier 31 is a negative feedback circuit for the inverting amplifier.

The output terminal of the operational amplifier 29 is connected to the non-inverting input terminal of the comparator 18 via a resistor 35,
The comparator 18 compares the output voltage of the operational amplifier 16 and the output voltage of the operational amplifier 29 and applies a pulse to the differentiating circuit [ ], and the output of the differentiating circuit [ ] is applied to the gate of the thyristor 7 of the ignition device [ ]. The connection point between this resistor 35 and the non-inverting input terminal of the comparator 18 is grounded via a capacitor 36.

Note that the output voltage of the resistor 35 is configured to be supplied to the non-inverting input terminal of the comparator 18 only when the output terminal Q of the FF circuit 13 is at a high level.

Next, the operation of the engine ignition timing control device of the present invention configured as described above will be explained with reference to the operation diagrams shown in FIGS. 2 to 6.

Figure 2 A is the crank position of the engine, and TDC
is the top dead center of the engine, t ₁ is the ignition position at the time of retardation, t ₂ is the ignition position at the time of advance, and t _a is an arbitrary ignition position on the way from t ₁ to t ₂ .

Figure 2 (b) shows the output voltage of the signal coil 8, where the voltage in the direction of the arrow a in Figure 1 is at _t1 , and the voltage in the direction of arrow b is _{at t2.}
The dots in Figure 2 indicate that the
The voltage waveforms of each symbol C to F' shown in the figure are shown.

When the b-direction voltage of the signal coil 8 is applied to the set input terminal S of the FF circuit 13, the output terminal Q becomes a high level, so that the electric charge of the capacitor 15, which was previously charged to the polarity shown in FIG. It is discharged at the current [I ₂ ] shown.

_I2 =F. High level voltage of F circuit 13 - reference voltage V ₁ /resistance value of resistor 14 If capacitor 15 is discharged, operational amplifier 16
The output voltage D of the comparator 17 drops linearly with a constant slope as shown in _FIG . When this voltage is applied to the reset terminal R of the FF circuit 13, the output terminal Q becomes a low level as shown in _FIG . Ru.

I ₁ =Reference voltage V ₁ /Resistance value of resistor 14 As shown in the above formula, discharge current I ₁ and I ₂ are the resistance value of resistor 14, the high level voltage of output terminal Q of FF circuit 13, and the reference voltage. If V ₁ is constant, it is constant regardless of engine rotation, and therefore operational amplifier 1
As shown in FIG. 2D, the output terminal voltage of No. 6 also rises or falls at a constant slope regardless of the engine speed.

In this way, the output terminal voltage of the operational amplifier 16 is t ₂
The voltage starts to fall from the moment when the signal b voltage is generated at the position, and the output voltage reaches the reference voltage of the comparator 17.
When the voltage reaches V ₂ , a triangular wave output starts to rise, and this voltage is applied to one end of the comparator 18 and compared with the voltage V _G at the non-inverting input terminal of the comparator 18. During the period when the triangular wave voltage is lower than the voltage V _G The output terminal voltage becomes high level.
This state is shown in FIG.

When the output voltage of the comparator 18 rises from a low level to a high level, it is differentiated by a differentiating circuit [ ] which is a rising detection circuit, and the voltage shown in FIG. 2 is generated at point F in FIG. 1. This differential voltage is applied to the gate of the thyristor 7 to drive the thyristor 7, and at the same time, the capacitor 19 is charged with charges in the direction shown. This charge is discharged through the diode 20 when the output terminal of the comparator 18 transitions to a low level, and prepares for the next charging.

When the differential voltage F is generated in the differential circuit [ ], the thyristor 7 operates, that is, the ignition timing of the engine is reached.The relationship between the ignition timing and the rotation of the engine will be explained.

Figure 3 is an extracted version of Figure 2 D.
As mentioned above, the slope of the rise and fall of the voltage at point D in FIG. 1 is constant regardless of the engine speed. Therefore, the ratio β/T in FIG. 3 is always constant.

From t ₂ where the angle signal b is generated, the voltage D becomes the voltage V _G
If V _G is constant, the engine rotational speed is N, the discharge period of I ₂ is β, and the period of one rotation of the engine is T, then the time α required for reaching this value is as follows.

α=β−360°t/T =β−360°Nt/60=β−6Nt…(1) Here, t is the time for the voltage D to reach the value of _V2 from the value of _VG , and the following It is expressed by the formula.

t=(V _G −V ₂ )・Capacity of capacitor 15/I ₂ ...
(2) Substituting this equation (2) into equation (1), α=β −6N(V _G −V ₂ )・Capacity of capacitor 15/I ₂ ...
(3) As mentioned above, the ratio of β to the period T is constant regardless of the rotation, that is, it is a constant angle. Therefore, the voltage V _G , the reference voltage V ₂ , and the capacitor 15
If the capacity of is constant, the crank angle α in Figure 3 is (3)
From the formula, it is only related to the rotation speed N, and decreases proportionally as the rotation increases. The angle α is the angle from point t ₂ where the signal voltage b occurs to t _a where the differential pulse of F occurs in Fig. 2, and the variation of α is t _a
This is nothing but a change in position, and as the rotational speed increases, the t _a point approaches the t ₂ point, indicating that the angle advances.

When the engine speed is low, α becomes large, and when the point t _a approaches the TDC side from the point t1 in Fig. ₂ , the voltage in the direction of the arrow a of the signal coil 8 becomes the second voltage at the gate of the thyristor 7 in Fig. 1. Figure t: The charge is added at _one point, and the thyristor 7 becomes conductive, and the charge on the capacitor 4 increases to the ignition coil 5.
is discharged to the primary coil 5a, and generates a high voltage in the secondary coil 5b to ignite the engine. At that time, the pulse of t _a lags behind t ₁ and does not contribute to engine ignition.

The rotation of the engine increases and the angle α becomes smaller, t _a
When the point advances from the _t1 point, the thyristor 7 is driven by the voltage shown in FIG. 2 to ignite the engine, and the a voltage at _t1 does not contribute to engine ignition. As the engine speed increases further, the t _a point advances further and finally ignition occurs at the t ₂ point.

When the rotation of the engine exceeds a certain value and the voltage D at _point t shows a value lower than V _G , the output of the F/F circuit 13 becomes high level due to the voltage b of the signal coil 8. , in response to this voltage, V _G is applied to the non-inverting input of the comparator 18 and ignites, so that the ignition position is set to the _t2 position. This state is shown in Fig. 4. When the engine rotation is below N ₁ , ignition occurs at t ₁ , and between N ₁ and N ₂ , as the rotation increases, the ignition timing advances as in the t _a period. For N ₂ or more, it is fixed at t ₂ .

Next, the operation of the block [ ] in FIG. 1, which is the gist of the present invention, will be explained. In response to the change in which the output terminal of the F/F circuit 13 shifts to high level, the resistor 21,
The capacitor 22 is charged to the illustrated polarity through the capacitor 22 and the diode 23, and the F/F circuit 13
When the output of the FF circuit 13 transitions to a low level, this charge flows from the non-inverting input terminal of the operational amplifier 26 to the inverting input terminal of the operational amplifier 26 via a ground circuit (not shown) of the F.F circuit 13, and the output terminal of the operational amplifier 26 becomes a high level. The output terminal of the operational amplifier 26 becomes high level only during the period when the discharge pulse of the capacitor 22 is applied, and this period is constant regardless of the rotation speed, and the number of pulses applied increases in proportion to the rotation, so the integrator The output voltage of the operational amplifier 26, capacitor 27, and resistor 25 that make up the circuit (voltage at point H in Figure 1)
increases with rotation.

The voltage at the H point is applied to the inverting input terminal of the operational amplifier 29 via the resistor 28, and the output terminal voltage of the operational amplifier 29 is not shown until the H point voltage reaches a constant value determined by the non-inverting input terminal voltage _V3 of the operational amplifier 29. If a constant voltage determined by the power supply circuit is maintained, and the H point voltage reaches a certain value and further increases as the rotation increases, the output voltage of the operational amplifier 29 forming an inverting amplifier begins to decrease.

The output voltage of operational amplifier 29 is also
1, and if this input voltage falls below the reference voltage _V4 of the operational amplifier 31, the output voltage of the operational amplifier 31 decreases, and a current flows from the inverting input terminal of the operational amplifier 29 via the diode 33. Since it flows into the operational amplifier 31 and lowers the input voltage of the operational amplifier 29, the output voltage of the operational amplifier 29 does not fall below a certain value determined by the reference voltage _V4 . This is shown as a characteristic in FIG.

When the engine speed increases and reaches _N3 , the output of the operational amplifier 26 becomes the bias voltage of the operational amplifier 29.
A constant value determined by V ₃ is reached and the op amp 29
The output remains constant up to N ₃ , but begins to decline above N ₃ . When the engine rotation reaches N ₄ , the output voltage of the operational amplifier is the reference voltage of operational amplifier 31.
Reach V ₄ and stop its decline.

The output voltage of the operational amplifier 29, that is, the final stage output voltage V _G of the FV circuit [ ] is applied to the non-inverting input terminal of the comparator 18 when the output terminal Q of the FF circuit 13 is at a high level, and be compared. Regarding the advance angle function explained in FIGS. 2 to 4 in the upper part, if the value of V _G applied to the non-inverting input terminal of the comparator 18 changes as shown in FIG. becomes N and V _G ,
If V _G decreases as N increases, α increases with rotation. In other words, it retards the angle.

FIG. 6 shows this relationship; when the engine rotation is _N3 , α has an angle of _α1 . When the engine speed reaches N ₄ , the ignition position decreases to α' ₁ , but as the input voltage at the non-inverting input terminal of the comparator 18 decreases from V _G1 to V _G2 , the ignition timing increases to α ₂ . In other words, it will be delayed. V _G
If V _G2 remains at the value of V G2 and the engine speed further increases to _N5 , the ignition position is advanced to _α3 again.

If this is expressed in Fig. 4, the ignition position fixed at t ₂ as described above will be delayed again as V _G decreases, and will be delayed as the rotation increases with the slope of t _b , and then V _G will increase to the value of the reference voltage V ₄ . When the angle is maintained at tc, the advance angle is again advanced as shown in Fig. 4 _tc .

The slope of t _a , which is the advance angle characteristic, the slope of t _c , the slope of t _b , which is the retard angle characteristic, and their rotational speed settings are the settings of the resistors 14 and 25 in FIG. 1, or the settings of V ₂ , V ₃ ,
It can be changed arbitrarily by setting the reference voltage of _V4 .

In order to improve the accuracy of the characteristics, the voltage V _G is obtained from a constant voltage power supply as shown in the embodiment of FIG. The voltage may be lowered as the voltage rises.

Furthermore, in order to simplify the circuit, it is of course possible to stop the output voltage from decreasing by clipping the input voltage of the operational amplifier 29 with a Zener diode 37, as shown in the embodiment of FIG. be.

Furthermore, by using the output terminal of the F/F circuit 13, it is also possible to reversely change the voltage shown in _FIG .

As explained above, according to the engine ignition timing control device of the present invention, the ignition position can be advanced or retarded or the V-type retard advance reference voltage _V4 can be selected in accordance with the engine requirements. It is possible to obtain various advance angle characteristics such as obtaining a constant ignition position after retardation.
Moreover, in order to obtain these characteristics, it is possible to obtain excellent ignition timing that can optimize engine output from low speeds to high speeds without complicating the advance angle circuit.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of the ignition timing control device for an engine according to the present invention, and FIGS. 2 to 6 are explanatory diagrams for explaining the operation of the ignition timing control device for an engine according to the present invention. 7 and 8 are circuit diagrams showing different parts from FIG. 1 of other embodiments of the ignition timing control device for an engine according to the present invention. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Claims] 1. Signal generating means for generating positive and negative signals at a predetermined crank position in synchronization with engine rotation, full-wave rectification of this signal, and a first signal as a first trigger for engine ignition timing. When this signal is generated by a second signal, the first output decreases or increases at a constant current with a constant slope, and when this first output reaches the first reference voltage, the current becomes constant. an integrator that generates a second output that rises or falls at a constant slope; when the first output reaches a second reference voltage in the process of reaching the first reference voltage, an a circuit that generates a second trigger signal;
One signal is used to obtain one ignition timing, and a second trigger signal is used to advance the ignition timing as the engine speed increases, and when the engine speed reaches a predetermined value, the ignition timing is set to advance. The circuit includes a circuit that controls ignition timing by lowering a second reference voltage as the rotation increases with an inclination of . An ignition timing control device for an engine, characterized in that it is configured as follows. 2. Replace the second signal of the signal generating means with a pulse signal having a frequency proportional to the rotation of the engine and a constant time width using a flip-flop circuit and a differential circuit,
The ignition timing control device for an engine according to claim 1, characterized in that this pulse is replaced by a second reference voltage that decreases at a predetermined rotation speed or higher using an integrator and an inverting amplifier. 3 Set up a bypass circuit that obtains a second reference voltage from a constant voltage power supply and operates when the engine rotation exceeds a predetermined value,
2. The ignition timing control device for an engine according to claim 1, wherein the second reference voltage is lowered at a constant slope as the rotation of the engine increases by bypassing the second reference voltage. 4 The second reference voltage decreases as the engine speed increases, and when the engine speed reaches a predetermined value or higher, the second reference voltage stops decreasing and the retarded ignition timing is advanced again. An ignition timing control device for an engine according to claim 1, characterized in that it is configured as follows. 5 A negative feedback circuit is provided in the inverting amplifier in order to stop the second reference voltage from decreasing at a predetermined rotation speed or higher, and the negative feedback circuit is configured so that the negative feedback circuit is activated when the output of the inverting amplifier decreases to a certain value. The engine according to claim 1 or 2, characterized in that the input voltage is clipped below a certain value by providing a threshold value or by providing a bypass circuit of a constant voltage element at the input end of the inverting amplifier. ignition timing control device.