JPS6240125Y2 - - 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 various parameters of the engine, such as engine speed.

Conventionally, this type of device detects the trigger level of the signal voltage of the signal generator, which is generated in synchronization with the engine rotational speed and corresponds to the ignition timing, and opens and closes the semiconductor switching element of the ignition device, thereby controlling the secondary of the ignition coil. The signal voltage waveform was used to determine the ignition timing of the engine. Therefore, since the ignition timing is determined by the signal voltage waveform, it has not been possible to sufficiently correspond to the ignition timing required by the engine.

This invention is intended to solve this problem, and its purpose is to obtain an ignition timing characteristic in which the ignition timing is retarded at a predetermined slope from a constant maximum advance angle.

This invention will be explained below with reference to the embodiment shown in FIG. In the figure, reference numeral 1 denotes an ignition device, and this embodiment uses a well-known CD ignition device as an example, and is configured as follows. That is, reference numeral 1 denotes a generating coil of a magnet generator (not shown) which generates positive and negative alternating current voltages in synchronization with the rotation of the engine. 2 and 3 are diodes that rectify the output of the generator coil 1; 4 is a capacitor that is charged by the rectified output of the diode 2;
Reference numeral 5 denotes an ignition coil connected to the discharge circuit of the capacitor 4, which consists of a primary coil 5a connected in series with the capacitor 4 and a secondary coil 5b connected to the ignition plug 6. A thyristor 7 is a semiconductor switching element connected to the discharge circuit of the capacitor 4. When the thyristor 7 is conductive, the charge in the capacitor 4 is discharged to the primary coil 5a.
is an ignition timing control circuit that is a feature of the present invention, and is configured as follows. That is, 8 is a signal coil which is an angular position detection device, and is attached to the above-mentioned magnet generator together with the generator coil 1. This signal coil 8 generates positive and negative angle signals in synchronization with the rotation of the engine, and among them, the first angle Signal b is the predetermined crank position of the engine, that is, the maximum advance angle position required by the engine.
T ₂ , the second angle signal a is equal to the first angle signal b
Crank position T ₁ that is a predetermined angle ahead of the occurrence position of
corresponds to 9 and 10 are full-wave rectifiers of the positive and negative angle signals a and b of the signal coil 8 to produce first and second angle signals a,
It is a diode that separates into b.

is a type of flip-flop circuit (hereinafter referred to as the 1st F.F circuit) composed of a thyristor 11, a transistor 12, and a resistor 13. The gate of the thyristor 11 is connected to the B terminal of the signal coil 8, and the base of the transistor 12 is connected to the signal coil 8. It is connected to the A end of the coil 8. 14 is a flip-flop circuit (hereinafter referred to as a second F.F circuit); 15 is a register; 16 is a capacitor; 17 is an operational amplifier (hereinafter referred to as an operational amplifier); the register 15 and the capacitor 16 constitute an integrator. 18 is a voltage comparator (hereinafter referred to as a comparator), and 19 is a NOR gate. The set terminal S of the second FF circuit 14 is connected to the A terminal of the signal coil 8, and the output terminal Q is connected to the inverting input terminal (hereinafter referred to as the (-) terminal) of the operational amplifier 17 via the register 15. The output terminal of the operational amplifier 17 is connected to the (-) terminal of the comparator 18 and also to its own (-) terminal via the capacitor 16 . In addition, the non-inverting input terminal (hereinafter referred to as (+) terminal) of the operational amplifier 17 has a reference voltage
Biased to V ₁ , (+) of comparator 18
The end is grounded. Further, the output terminal of the comparator 18 is connected to the reset terminal R of the second FF circuit 14. Output terminal Q of second FF circuit 14 and thyristor 1
1. The output terminal of the first FF circuit composed of a transistor 12 and a register 13 is a NOR gate 19
, and its output end is connected via a capacitor 20 to the gate of the thyristor 7 of the ignition device. 21 is a diode connected between the gate of the thyristor 7 and ground. This capacitor 20 and diode 21 constitute a pulse rise detection circuit.

The operation of the embodiment configured as described above will be explained in detail using the operation diagram shown in FIG. H shown in Figure 2 is the engine crank position, TDC is the top dead center of the engine, T ₂ is the maximum advanced angle signal at which the first angle signal b is generated, and T ₁ is a predetermined angle ahead of the first angle signal b. This is the reference position at which the second angle signal a is generated. A to G are voltage waveforms at each part shown in Figure 1,
It is a pulse waveform.

The engine shall require the ignition timing characteristics shown in Figure 4.

First, the operation when the engine is rotating at a constant speed at a rotation speed higher than N ₁ and lower than N ₂ shown in FIG. 4 is as follows. That is, the signal coil 8 receives the crank position T ₁ once per revolution of the engine.
Corresponding to T ₂ , first and second angle signals b and a whose angular widths are narrow and change sharply are generated. One of these days,
When the second angle signal a is input to the set terminal S of the second FF circuit 14, its output terminal Q becomes high level, so that the capacitor 16, which has been charged in advance to the polarity shown in the figure,
The charge is discharged by the current I ₂ shown in the following equation.

I ₂ = High level voltage of the second FF circuit 14 - Angle voltage V ₁ /Resistance value of the register 15 As shown in the above formula, this discharge current I ₂ is determined by the resistance value of the high level voltage register 15 of the second FF circuit 14 and the reference value. If the voltage V ₁ is constant, it will remain a constant value even if the engine speed changes. When the capacitor 16 is discharged with the discharge current _I2 , the output voltage D of the operational amplifier 17
As shown in FIG.
8, a positive pulse voltage is generated at the output of the comparator 18, and the second FF
This positive pulse voltage is input to the reset terminal R of the circuit 14, and is inverted so that the output terminal Q becomes a low level.

Due to the low level of the output terminal Q of the second F.F circuit 14, the capacitor 16 is charged again to the illustrated polarity with a current _I1 shown in the following equation.

I ₁ = Reference voltage V ₁ /Resistance value of resistor 15 As shown in the above formula, this charging current I ₁ is
If the resistance value of 5 and the reference voltage _V1 are constant, the value will be constant even if the engine speed changes. Therefore, the charging voltage of the capacitor 16, that is, the operational amplifier 17
As shown in FIG. 2D, the output voltage D of the motor increases linearly with a constant slope regardless of the rotation speed. When the output voltage D of the operational amplifier 17 reaches the power supply voltage Vcc while rising, it reaches a ceiling and becomes a constant value at the power supply voltage.

In this way, the output voltage D of the operational amplifier 17 is
The output voltage becomes a triangular wave that drops from the generation position _T1 of the angle signal a and rises again when the output voltage D reaches the (+) terminal voltage of the comparator 18. This triangular wave is set so that when the engine speed is below _N2 , it reaches a ceiling at the power supply voltage Vcc while increasing.

On the other hand, the operation of the first FF circuit composed of the thyristor 11, the transistor 12, and the register 13 is as follows. The first signal coil 8
The angle signal b is input to the gate of the thyristor 11, and the thyristor 11 becomes conductive, so that the anode end of the thyristor 11 is inverted from a high level based on the power supply voltage Vcc to a low level. Also,
The second angle signal a of the signal coil 8 is transmitted to the transistor 1
During the generation period of the second angle signal a, the transistor 12 becomes conductive, and the anode current of the thyristor 11 is bypassed by the transistor 12, so that the thyristor 11 loses its self-holding effect and becomes non-conducting. Reversed to conductive state. This is due to the difference in operating characteristics between the thyristor 11 and the transistor 12. Since the transistor 12 becomes non-conductive when the second angle signal a becomes approximately zero, the connection point between the collector of the transistor 12 and the anode of the thyristor 11, that is, the output signal E of the first F/F circuit
is inverted from low level to high level. To explain this operation in detail with reference to FIG. ₂ , the output signal E of the first F.F circuit is inverted from high level to low level at the generation signal T2 of the first angle signal b, and the second angle signal The second angle signal a at the generation position _T1 of a
When it reaches approximately zero, it is reversed from low level to high level again.

When the output signal C of the second FF circuit 14 mentioned above is input to the first gate of the NOR gate 19, and the output signal E of the second FF circuit is input to the second gate, the output signal F of the NOR gate 19 is input. is Figure 2F
As shown in the figure, the second FF circuit 14 of the NOR gate 19
When the output signal C of the second FF circuit 14 falls from a high level to a low level, it is inverted from a low level to a high level, and when the output signal C of the second FF circuit 14 is similarly inverted from a high level to a low level when it rises from a low level to a high level. do. When the output signal F of the NOR gate 19 is inverted from a low level to a high level, it is differentiated by a pulse rise detection circuit and a trigger voltage G shown in FIG. 2G is generated.

That is, the capacitor 20 is charged to the polarity shown by the rising output signal F of the NOR gate 19, and the thyristor 7 is charged at the position M in FIG. 2 by the charging current.
Trigger voltage G is generated.

The charge on the capacitor 20 is transferred to the NOR gate 19.
is discharged through the diode 21 due to the low level of , and prepares for the next operation.

As described above, the thyristor 7 receives the first angle signal b
Trigger voltage G is received at a position M that lags behind the crank position _T2 where ignition occurs, and conduction occurs, and in order to discharge the charge in the capacitor 4 to the primary coil 5a of the ignition coil 5, a high voltage is applied to the secondary coil 5b. This will cause the spark plug 6 to catch fire.

According to the above explanation, when the engine speed is in the rotation range higher than _N1 and lower than _N2 shown in FIG.
It will be understood that the point in time when the (+) terminal voltage of 8 is reached is the ignition timing and the engine is ignited.

Next, the operation of retarding the ignition timing at a constant slope as the engine speed increases from _N1 to _N2 will be described in detail with reference to FIG. Here, as described above, the point in time when the output voltage D of the operational amplifier 17 reaches the (+) terminal voltage of the comparator 18 becomes the ignition timing of the engine. Furthermore, the discharging current I ₂ and charging current I ₁ of the capacitor 16 that generate the charging voltage for the operational amplifier 17 are constant values regardless of the engine speed, and the slope of the drop and rise of the operational amplifier 17 output voltage D is also constant. Also, as described above.

Now, assume that the interval between the crank position T ₁ and the next crank position T ₁ shown in FIG. 2 is the time width when the engine rotation speed is higher than N ₁ and lower than N ₂ . Capacitor 16 at this Na rotation speed
is discharged with a constant discharge current _I2 from the crank position _T1 where the second angle signal a is generated, so the output voltage D of the operational amplifier 7 drops linearly with a constant slope as shown at 51, and this output At the moment when the voltage D drops below the (+) terminal voltage of the comparator 18, that is, at a position shifted by an angle α from the crank position _T1 ,
The 2FF circuit 14 is reset by the positive pulse voltage of the comparator 18, and the output terminal Q of the FF circuit 14 becomes low level. Then, the capacitor 16 is charged again with a constant charging current _I1 , and the output voltage D of the operational amplifier 17 increases linearly with a constant slope as shown at 52. This output voltage D is
The 2FF circuit 14 reaches the power supply voltage Vcc at a position shifted by an angle β from the reset position, and thereafter the voltage Vcc
It is maintained at , reaches a plateau, and moves to the next crank position.
At _T1 , when the second FF circuit 14 is set by the second angle signal a and the output terminal Q becomes high level, the capacitor 16 starts discharging again with the constant discharge current _I2 .

Therefore, the angle between the crank position T ₁ and the position M where the falling output voltage D at the Na rotation speed reaches the (+) terminal potential of the comparator 18, that is, the retard angle α, is the angle between each crank position T ₁ by 4π. Then, α=4π・t・Na/60.

Here, t: Time Na: Number of rotations The time (t) shown in the above equation is the time when the discharge current _I2 is constant from the crank position, and the output voltage D that the operational amplifier 17 drops is the (+) terminal potential of the comparator 18. This time (t) is the time required for the output voltage D to reach the (+) terminal voltage of the comparator 18 because the discharge current I ₂ and the power supply voltage Vcc are constant values regardless of the rotation speed. is constant, that is, a constant time (t), and therefore, this time (t) is constant regardless of the rotation speed.

Therefore, as can be understood from the above formula, the retardation angle α is determined by a constant time (t) as a function of the rotation speed (N), and increases proportionally as the rotation speed increases from N ₁ to N ₂ . As a result, the ignition timing is retarded as the rotational speed increases from _N1 to _N2 . In this way, in the rotation range where the rotational speed is higher than N ₁ and lower than N ₂ , the crank position T ₃ is delayed from the crank position T ₂ where the first angle signal b is generated.
The angle is retarded at a predetermined slope.

This retard angle α gradually increases toward 4π in proportion to the rotational speed, and when the rotational speed reaches _N2 , the position where the output voltage D of the operational amplifier 17 reaches the power supply voltage Vcc during the charging process of the capacitor 16 is the next crank position. Since the voltage becomes T ₁ , the output voltage D does not reach a peak.

Next, the operation when the number of revolutions is N1 or _more will be explained using FIG. When the rotation speed increases to _N2 , the timing at which the output voltage D of the operational amplifier 17 reaches the power supply voltage Vcc coincides with the next crank position _T1 at which the second angle signal a is generated, so the output voltage D becomes equal to the power supply voltage Vcc.
As soon as it reaches , it will descend. Furthermore, when the rotational speed increases to more than N ₂ , the output voltage D of the operational amplifier 17 does not exceed the power supply voltage Vcc, so there is no plateau, and therefore the capacitor 16 has a constant charging/discharging current I ₁ , I that is not related to the rotation of the engine. ₂ , the output voltage D of the operational amplifier 17 drops with a constant slope from the crank position _T1 as shown in FIG. When it reaches , it rises again with a constant slope, and repeats the operation of rising again with a constant slope at the next crank position _T1 . Since the charging and discharging currents I ₁ and I ₂ of the capacitor 16 are constant currents in this way, the slope of the output voltage D of the operational amplifier 17 is constant, and the slope of the output voltage D of the operational amplifier 17 is constant.
Since the proportion of the slow angle α in one rotation based on the angle between _T1 is constant, when the rotation speed is _N2 or more, the output voltage D drops and reaches the (+) terminal voltage of the comparator 18. The timing becomes constant at the crank position _T3 regardless of the rotational speed, and the trigger voltage G is generated at this crank position _T3 , resulting in a constant ignition timing as shown in FIG.

Next, the operation when the number of rotations is _N1 or less will be explained. When the rotation speed is below N ₁ , the retard angle α is smaller than the angle _between each crank position T ₁ and _{T 2 shown} in FIG. Therefore, the output signal c of the second FF circuit 14 is at a high level during the delay angle α, and this high level output signal c is input to the first gate of the NOR gate 19. Here, the output signal E of the first FF circuit is inverted from high level to low level at the generation position _T2 of the first angle signal b, and the output signal E is inverted from high level to low level at the generation position _T1 of the second angle signal a. As described above, the low level is reversed again to the high level at the time of reaching zero. The output signal E of this first FF circuit and the output signal C of the second FF circuit 14 are
The signal is input to each of the first and second gates of the NOR gate 19, and the output terminal F of the NOR gate 19 generates an output signal F at a high level during a period when the output signals C and E are both at a low level. This high level period of the output signal F is a period from the crank position _T2 where the first angle signal b is generated to the next crank position _T1 where the second angle signal a is generated. This NOR gate 19
At the time when the output signal F is reversed from low level to high level, that is, at crank position _T2 , the pulse rise detection circuit generates the trigger voltage G shown in Fig. 2G, and the generation time of this trigger voltage G is the ignition timing. becomes. In this way, when the rotational speed is _N1 or less, the output voltage E at which the first FF circuit is inverted from high level to low level by the first angle signal b is
The timing at which the output terminal F of the NOR gate 19 that is applied to the second gate of the NOR gate 19 is reversed from low level to high level is determined by the first angle signal b, and the timing at which the first angle signal b is generated becomes the ignition timing. , this ignition timing becomes constant at T ₂ shown in FIG. 4, regardless of the rotation speed.

As detailed above, according to the embodiment of the present invention, the first angle signal b is synchronized with the engine rotation speed and corresponds to the maximum advance angle position _T2 , and the reference point is a predetermined angle advanced from the maximum advance angle position _T2 . Using the second angle signal a corresponding to the position T ₁ , the maximum advanced angle position T ₂ at which the first angle signal b is generated in the rotation range of rotation speed N ₁ or less is determined.
The charging/discharging voltage of the capacitor 16, which repeats discharging and charging at constant discharging/charging currents I ₂ and I ₁ based on the second angle signal a in the rotation range where the rotational speed is higher than N ₂ with the ignition timing as the ignition timing, that is, the operational amplifier When the discharge voltage output 51 reaches the (+) terminal potential of the comparator 18, it is reversed to the charging voltage 52, and the charging and discharging currents I ₁ and I ₂ of the capacitor 16 become Since it is a constant current, the angular proportion of the discharge voltage 51 during one rotation is constant, and the advance angle α until the discharge voltage 51 reaches the (+) terminal potential of the comparator 18 is determined based on the second angle signal a. Since the angle is constant, the ignition timing can be obtained by setting the position _T3 , which is delayed from the maximum advance angle position _T2 , as the constant maximum retard angle position. When the rotation speed is lower than _N2 , the power supply voltage Vcc and the (+) terminal potential of the comparator 18 are finite, so when the rotation speed is lower than _N2 , the time of the discharge voltage 51 is a fixed time, so the rotation speed increases. As a result, the timing at which the discharge voltage 51 reaches the (+) terminal potential of the comparator 18 is delayed, and by retarding the crank position from the crank position _T2 to the maximum retard angle position _T3 at a constant slope, the timing shown in FIG. The ignition timing characteristics shown in FIG.

Note that the present invention is not limited to the above-mentioned embodiments, but includes various embodiments.

For example, the maximum advance angle position T ₂ is the first angle signal b
It can be set arbitrarily by changing the time of occurrence. Also, the slope of the retardation angle with respect to the rotation speed N can be changed by changing the setting of the reference position T ₁ or by changing the discharge current I ₂ of the capacitor 16.
It can be set arbitrarily by changing the constant time (t) by adjusting the reference voltage V ₁ or the (+) terminal potential of the operational amplifier 18 . Furthermore,
Even when the rotational speed is N2 or _higher , the maximum retardation angle position _T2 can be arbitrarily set by adjusting the charging/discharging currents _I1 and _I2 of the capacitor 18. Further, although the first and second angle signals a and b utilize the positive and negative alternating current outputs of a single signal coil 8, independent signal coils 8a and 8b may be used, respectively, as shown in FIG.

As described above, this invention has a first crank position that is synchronized with the rotation of the engine, and a second crank position that is advanced from the first crank position.
first and second signal generating means for generating a second angle signal; a discharge voltage having a constant slope that discharges at a constant current due to the generation of the second angle signal; and when the discharge voltage reaches a first reference value. an integrator including a capacitor that outputs a charging voltage having a constant slope that is charged with a constant current;
a first circuit means that generates an output when a reference value is reached; a second circuit means that receives the first and second angle signals and generates an output between the first and second crank positions; logic means for generating an ignition signal by the slower output of the outputs of the circuit means, and the rotation range until the engine speed reaches a first predetermined value is such that the discharge voltage of the integrator is a first reference value. The timing at which the first angle signal is generated is set to be later than the timing at which the angle signal is reached.
Furthermore, the engine rotation range until reaching a second predetermined value that is larger than the first predetermined value is such that the charging voltage is within the second predetermined value.
When the reference value is reached, the second reference value is maintained, and when the rotation range exceeds the second predetermined value, the second reference value is maintained during the charging process until the charging voltage reaches the second reference value.
Since the discharge is caused by the generation of the angle signal, ignition is performed at a constant advance angle by the first angle signal generated at the first crank position until the engine speed reaches the first predetermined value. , in the rotation range that exceeds the first predetermined value and reaches the second predetermined value, the ignition timing is set to have a retard characteristic of a predetermined slope based on the second angle signal, and further, when the rotation exceeds the second predetermined value, In this range, the ignition timing has a certain retard characteristic based on the second angle signal, and has the effect of being able to sufficiently correspond to the ignition timing required by the engine.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing an embodiment of this invention, Figs. 2 and 3 are operational waveform diagrams explaining the operation of the embodiment of Fig. 1, and Fig. 4 is an ignition diagram obtained by the circuit shown in Fig. 1. The timing characteristic diagram, FIG. 5, is a configuration diagram showing another embodiment of the signal coil that generates the first and second angle signals a and b. In the figure, the ignition timing control circuit is the 1FF
The circuit is a pulse rising detection circuit, 8, 8a, 8
b is a signal coil, 9, 10, 21 are diodes,
11 is a thyristor, 12 is a transistor, 13,
15 is a register, 14 is a second FF circuit, 16, 20
is a capacitor, 17 is an operational amplifier, 18 is a comparator, and 19 is a NOR gate. Note that the same reference numerals in each figure indicate the same parts.

Claims (1)

[Scope of utility model registration request] first and second signal generating means for generating first and second angle signals respectively at a first crank position synchronized with the rotation of the engine and at a second crank position advanced from the first crank position; A capacitor that outputs a discharge voltage having a constant slope that is discharged with a constant current by generation of an angle signal, and a charging voltage that has a constant slope that is charged with a constant current when the discharge voltage reaches a first reference value. an integrator comprising: a first circuit means for generating an output when the discharge voltage reaches the first reference value; receiving the first and second angle signals and generating an output between the first and second crank positions; a second circuit means, and logic means for generating an ignition signal by the slower output of each of the first and second circuit means, wherein the rotational speed of the engine is at a first speed.
The rotation range until reaching the predetermined value is set such that the first angle signal is generated later than the time when the discharge voltage reaches the first reference value, and the second The rotation range of the engine until the charging voltage reaches the predetermined value is the second
When the reference value is reached, it is maintained at this second reference value,
The engine ignition timing control device is characterized in that above the rotation range of the second predetermined value, the engine ignition timing control device causes a transition to discharging by generating the second angle signal during the charging process until the charging voltage reaches the second reference value.