JPS6252141B2 - - 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 engine parameters, 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 to control the secondary 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.

The present invention is intended to solve these problems, 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.

The present invention will be explained below with reference to the embodiment shown in FIG. In the figure, 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 which is a feature of the present invention, and is configured as follows. That is, 8 is a signal coil that 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 The signal 6 corresponds to a predetermined crank position in the machine, that is, the maximum advanced angle position _T2 required by the engine, and the second angle signal a corresponds to a crank position that is a predetermined angle ahead of the generation position of the first angle signal b.
Corresponds to T ₁ . Diodes 9 and 10 rectify the positive and negative angle signals a and b of the signal coil 8 and separate them into first and second angle signals b and a.

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 F/F circuit 14 is connected to the A terminal of the signal coil 8, and the inverting 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. There is. The output end of the operational amplifier 17 is connected to the (+) end of the comparator 18 and also to its own (-) end via the capacitor 16. Also, the non-inverting input terminal of the operational amplifier 17 (hereinafter referred to as the (+) terminal)
is biased to the reference voltage V ₁ and comparator 1
The (-) end of 8 is biased to the reference voltage _V2 .
Further, the output terminal of the comparator 18 is connected to the reset terminal R of the second F.F circuit 14. 2nd F・F
The output terminal Q of the circuit 14 is composed of the thyristor 11, the transistor 12, and the resistor 13.
The output end of the 1F.F circuit is connected to each input end of the NOR gate 19, and the output end thereof 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 2
0 and the diode 21 constitute a pulse rising detection circuit.

The operation of the embodiment configured as described above will be explained in detail using the operation diagram shown in FIG. J shown in Figure 2 is the engine crank position, TDC is the top dead center of the engine, T ₂ is the maximum advance angle position where the first angle signal b is generated, and T ₁ is the predetermined angle advance from the first angle signal b. This is the reference position at which the second angle signal a is generated. A to H 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 continuously rotating 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 F.F circuit 14, its inverted output terminal Q becomes a low level, so that the capacitor 16 is charged with a current I ₂ shown in the following equation.

I ₂ = Reference voltage V ₁ /Resistance value of resistor 15 As shown in the above formula, if the resistance value of resistor 15 and the reference voltage V ₁ are constant, this charging current I ₂ will remain constant even if the engine speed changes. value. Charging current _I2
When the capacitor 16 is charged at
As shown in FIG. 2D, the output voltage D increases linearly with a constant slope regardless of the rotation speed, and when it becomes higher than the (-) terminal potential of the comparator 18,
A positive pulse voltage is generated at the output of the comparator 18, and this positive pulse voltage is input to the reset terminal R of the second F.F circuit 14, and is inverted so that its inverted output terminal becomes high level.

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

I ₁ = High level voltage of the second F/F circuit 14 - Reference voltage V ₁ /Resistance value of the register 15 As shown in the above formula, this discharge current I ₁ is the resistance of the high level voltage register 15 of the second F/F circuit 14. If the value and the reference voltage V ₁ are constant, the value will be constant even if the engine speed changes. Therefore, capacitor 16
, that is, the output voltage D of the operational amplifier 17
As shown in FIG. 2D, it falls linearly with a constant gradient regardless of the rotation speed. When the output voltage D of the operational amplifier 17 reaches the ground voltage while falling, the ground voltage does not reach a ceiling and becomes a constant value.

In this way, the output voltage D of the operational amplifier 17 is
The output voltage becomes a triangular wave which increases from the generation position _T1 of the angle signal a and decreases 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 ground voltage during the drop.

On the other hand, the operation of the first F.F circuit composed of the thyristor 11, the transistor 12, and the register 13 is as follows. The first angle signal b of the signal coil 8 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. Further, the second angle signal a of the signal coil 8 is input to the base of the transistor 12, and the transistor 12 becomes conductive during the generation period of the second angle signal a, and the anode current of the thyristor 11 is bypassed by the transistor 12. Therefore, the thyristor 11 loses its self-holding effect and reverses to a non-conducting 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 F of the first F.F circuit changes from a low level to a high level. to be reversed. To explain this operation in detail with reference to FIG. ₂ , at the generation position T2 of the first angle signal b, the output signal F of the first F.F circuit is inverted from high level to low level, and the second angle signal At the point in time when the second angle signal a reaches approximately zero at the generation position _T1 of a, the second angle signal a is inverted from the low level to the high level again.

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

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

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 charging current I ₂ and the discharging current I ₁ of the capacitor 16 that generate the charging/discharging voltage in the operational amplifier 17 are constant values regardless of the engine speed, and the slope of the rise and fall of the output voltage D of the operational amplifier 17 is also constant. This is also as stated 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
Since charging is performed with a constant charging current _I2 from the crank position _T1 where the second angle signal a is generated, the output voltage D of the operational amplifier 7 rises linearly with a constant slope as shown in 51, and this output At the moment when the voltage D rises above the (-) terminal voltage of the comparator 18, that is, at a position shifted by an angle α from the crank position _T1 ,
The 2F/F circuit 14 is reset by the positive pulse voltage of the comparator 18, and the inverted output terminal of the FF circuit 14 becomes high level. Then, the capacitor 16 is discharged again with a constant discharge current _I1 ,
The output voltage D of the operational amplifier 17 drops linearly with a constant slope as shown at 52. This output voltage D reaches the ground voltage at a position shifted by an angle β from the device where the second F/F circuit 14 is reset, is maintained at the ground voltage thereafter, reaches a ceiling, and reaches the second angle at the next crank position _T1 . 2nd F・F due to signal a
When the circuit 14 is set and the inverted output terminal Q goes to low level, the capacitor 16 is charged with a constant charging current again.
Start charging with I ₂ .

Therefore, the angle between the crank position T ₁ and the position M where the increasing 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 crank position _T1 is charged to a constant charging current _I2 , and the rising output voltage D of the operational amplifier 17 reaches 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 charging current I ₂ and the reference voltage V ₂ are constant values regardless of the rotation speed. , 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 equation, the retardation angle α is determined by the constant time t as a function of the rotation speed N,
As the rotation speed increases from N ₁ to N ₂ , it increases proportionally, and as a result, the ignition timing increases as the rotation speed increases.
It retards as it increases from N ₁ to N ₂ . In this way, in the rotation range where the rotational speed is higher than _N1 and lower than _N2 , the crank position is retarded at a predetermined slope from the crank position _T2 where the first angle signal b is generated to the delayed crank position _T3 . do.

This retard angle α gradually increases in proportion to the rotation speed toward 4π, and when the rotation speed reaches N ₂ , the position where the output voltage D of the operational amplifier 17 reaches the reference voltage V ₂ during the discharging process of the capacitor 16 is the position at which the next crank Since it matches the position _T1 , the output voltage D does not peak out.

Next, the operation when the number of rotations is _N2 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 the reference voltage.
As soon as it reaches V ₂ , it will descend. Furthermore, when the rotation speed increases to more than N ₂ , the operational amplifier 17
Since the output voltage D does not exceed the reference voltage V ₂ , there is no peaking out. Therefore, the capacitor 16 repeats charging and discharging with constant charging and discharging currents I ₂ and I ₁ that are not related to the rotation of the engine. Output voltage D
As shown in FIG. 3D, the output voltage D rises with a constant slope from the crank position _T1 , and when the output voltage D reaches the (-) terminal potential of the comparator 18, it falls again with a constant slope, and the next At crank position _T1 , the operation of rising at a constant slope is repeated again. Since the charging and discharging currents I ₂ and I ₁ of the capacitor 16 are constant currents in this way, the slope of the output voltage D of the operational amplifier 17 is constant, so that 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 increases 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 H 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 E of the second F.F circuit 14 is at a high level during the delay angle α, and this high level output signal E is input to the first gate of the NOR gate 19. Here, the 1st F.F circuit is the first
At the generation position _T2 of the angle signal b, the output signal F is inverted from high level to low level, and the second angle signal a
As described above, the second angle signal a is inverted from the low level to the high level again at the time when the second angle signal a reaches approximately zero at the generation position _T2 . This first
Output signal F of 1F/F circuit and 2nd F/F circuit 14
The output signal G of the NOR gate 19 is input to each of the first and second gates of the NOR gate 19, and the output terminal G of the NOR gate 19 generates an output signal G at a high level during a period when each output signal E and F are both at a low level. This high level period of the output signal G 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
At the time when the output signal G of the gate 19 is inverted from low level to high level, that is, at crank position _T2 , the pulse rise detection circuit generates the trigger voltage H shown in FIG. This is the ignition timing. In this way, when the rotational speed is _N1 or less, the first angle signal b
The timing at which the output voltage F at which the 1F/F circuit inverts from high level to low level is applied to the second gate of NOR gate 19 and the output terminal G of NOR gate 19 inverts from low level to high level is the first angle signal b. The timing of generation of this first angle signal b becomes the ignition timing, and 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 position is advanced by a predetermined angle from this maximum advance angle position _T2 . Using the second angle signal a corresponding to T ₁ , in the rotation range below the rotation speed N ₁ , the maximum advance angle position T ₂ at which the first angle signal b is generated is set as the ignition timing, and the rotation speed is higher than N ₂ . In the rotation range, the charging and discharging voltage of the capacitor 16 which repeats constant charging and discharging with the second angle signal a as a reference, that is, the discharging and charging voltage of the output voltage D of the operational amplifier 17 is obtained, and this charging voltage output 51 is the (-) of the comparator 18. ) When the terminal potential is reached, the discharge voltage is reversed to 52,
Since the charging and discharging currents I ₂ and I ₁ of the capacitor 16 are constant currents, the angular proportion of the charging voltage 51 during one rotation is constant, and the charging voltage 51 is adjusted to the ( -) Since the advance angle α until reaching the end potential is constant, the ignition timing can be obtained by setting the position T ₃ delayed from the maximum advance angle position T ₂ as a constant maximum retard angle position. The number of rotations
Reference voltage V ₂ and comparator 1 if lower than N ₂
Since the (-) terminal potential of 8 is finite, the rotation speed is
If the charging voltage 51 is lower than N ₂ , the charging voltage 51 increases as the rotation speed increases because the charging voltage 51 is a fixed time.
reaches the (-) terminal potential of the comparator 18 is delayed, and the maximum retard angle position _T3 is shifted from the crank position _T2 .
By retarding the angle at a constant slope, the fourth
The ignition timing characteristics shown in the figure can be obtained.

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

For example, the slope of the retardation angle relative to the rotation speed N can be determined by changing the setting of the reference position _T1 , adjusting the charging current _I2 of the capacitor 16, or adjusting the reference voltage _V1 or the (-) terminal potential of the comparator 18. It can be set arbitrarily by changing the constant time t. Further, even when the rotational speed is _N2 or more, the maximum retardation angle position _T3 can be arbitrarily set by adjusting the charging/discharging currents _I2 and _I1 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, the present invention utilizes the first angle signal generated at the first crank position and the second angle signal generated at the second crank position advanced from the first crank position to allow the first angle signal to reach the maximum speed. Obtain the angular timing, charge with constant current based on the second angular signal,
The integrator that repeats discharging outputs triangular charging and discharging voltages, and when this discharging voltage reaches the first reference value, it shifts to discharging, and since it is a constant current, charging at the second crank position and the next second crank position is performed. The voltage ratio remains constant even with changes in engine speed, and the timing at which this charging voltage reaches the first reference value retards with a constant slope to the maximum retard position as the speed increases. This is to obtain the ignition timing.

[Brief explanation of the drawing]

Fig. 1 is an electric circuit diagram showing an embodiment of the present 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
1F・F circuit is a pulse rising detection circuit, 8,
8a and 8b are signal coils, 9, 10, and 21 are diodes, 11 is a thyristor, 12 is a transistor, 13 and 15 are registers, 14 is a second F/F circuit, 16 and 20 are capacitors, 17 is an operational amplifier, and 18 is a comparator , 19 is a NOR gate. Note that the same reference numerals in each figure indicate the same parts.

Claims (1)

[Claims] 1. First and second signal generating means for generating first and second angle signals, respectively, at a first crank position in synchronization with the rotation of the engine and at a second crank position advanced from the first crank position; When the second angle signal is generated, a charging voltage with a constant slope is charged with a constant current, and when this charging voltage reaches the first reference value, a discharge voltage with a constant slope is discharged with a constant current. an integrator including a capacitor that outputs a voltage, and a first circuit means that generates an output when the charging voltage reaches the first reference value;
second circuit means for receiving an angle signal and generating an output for an angle period from said first crank position to said second crank position; and logic for generating an ignition signal based on the logic of each output of said first and second circuit means. means for maintaining the rotation range until the rotation speed of the engine reaches a predetermined value at the second reference value when the discharge voltage reaches the second reference value; An engine ignition timing control device characterized in that during a discharging process until reaching a second reference value, generation of the second angle signal causes a transition to charging.