JPS6242155B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a contactless switch for internal combustion engines that controls the primary current of an ignition coil to perform ignition operation using a primary current control switch operated by a control signal given at the ignition position of the engine. This relates to an ignition device.

In general, in internal combustion engines, it is necessary to keep the ignition position constant in the low speed range and advance the ignition position in the medium and high speed range, but depending on the engine, in order to obtain the desired characteristics, it is necessary to set the ignition position in the high speed range. It may be necessary to retard the ignition position for more than a few engine speeds, and the ignition position may be retarded in high-speed ranges to prevent overspeeding of the engine. Conventional ignition systems utilize the fact that the output of the signal generator that provides the signal that determines the ignition position increases as the engine speed increases, and the phase advances until it reaches the trigger level of the primary current control switch. The ignition position was delayed by obtaining an advance angle characteristic and bypassing a portion of the signal from the primary current control switch when the engine speed exceeds the set rotation speed in the high-speed region of the engine. However, when the advance characteristics are obtained using the output characteristics of the signal generator in this way, the ignition position advances considerably even at low speeds, which increases the fluctuation range of the ignition position at low speeds and impairs engine startability. There was a flaw that made it worse. In addition, if the ignition position advances too far in the medium-high speed range, engine operation will become unstable, so the maximum advance position must be set to the optimum position according to the characteristics of the engine. Since the advance angle characteristics are determined by the characteristics, it has been difficult to freely set the advance angle characteristics depending on the engine. Furthermore, in order to increase the output of the engine, it is desirable to keep the ignition position approximately constant until the set rotation speed starts retardation after advancing to the maximum advance position. With conventional devices that advance the ignition angle by adjusting the engine speed, when the engine speed exceeds a certain level, the ignition position tends to be delayed even if the engine speed is below the set speed, and it may not be possible to extract the maximum output from the engine. Ta.

The purpose of the present invention is to make it possible to easily adjust the advance angle characteristics, reduce fluctuations in the ignition position at low speeds, and start retardation after advancing to the maximum advance position in the high speed region. An object of the present invention is to provide a non-contact ignition device for an internal combustion engine that can fix the ignition position at the maximum advance position until a set rotation speed.

The present invention will be explained in detail below with reference to the illustrated embodiments.

FIG. 1 shows an embodiment of the present invention.
In the figure, 1 is the primary coil 1 whose one end is grounded.
2 is a capacitor connected in series to the primary coil 1a; 3 is a primary current connected in parallel to the series circuit of the capacitor 2 and the primary coil 1a; A thyristor is used as a control switch, 4 is a resistor connected between the gate and cathode of the thyristor 3, and P is a spark plug loaded on the secondary coil 1b. These constitute a capacitor discharge type ignition circuit 5. . In order to provide ignition energy to this ignition circuit, an exciter coil 6 is disposed within a magnet generator driven by the engine.
One end of the exciter coil 6 is connected to the anode of a diode 7 whose cathode is connected to the connection point between the capacitor 5 and the anode of the thyristor 3, and the other end of the exciter coil 6 is connected to the cathode of a diode 8 whose anode is grounded. A diode 9 whose anode is grounded is connected in parallel to both ends of the series circuit of the exciter coil 6 and the diode 8, and a thyristor 10 whose cathode is grounded is connected in parallel to both ends of the diode 8. A Zener diode 11 is connected in parallel between the anode and gate of the thyristor 10 with its anode facing the gate of the thyristor, and a resistor 12 is connected in parallel between the gate and cathode. Further, the anode of the diode 13 is connected to the anode of the thyristor 10, and the diode 1
A power supply capacitor 14 having a sufficiently large capacity is connected between the cathode of No. 3 and the ground. Exciter coil 6, diode 8, thyristor 10,
A power supply circuit 15 is composed of a Zener diode 11, a resistor 12, a diode 13, and a capacitor 14.

When the exciter coil 6 of the power supply circuit generates an output in the direction of the solid arrow shown in the figure, the capacitor 2 is charged through the diode 7 to the polarity shown.
Next, when a control signal is applied to the gate of thyristor 3, this thyristor 3 becomes conductive, and capacitor 2
is discharged through the thyristor 3 and the primary coil 1a. Since this discharge occurs in an extremely short time, current suddenly flows into the primary coil of the ignition coil 1, causing a large change in magnetic flux in the iron core of the ignition coil, which induces a high voltage in the secondary coil 1b, causing ignition. Spark occurs at plug P. Therefore, in the ignition circuit 5, the ignition position can be controlled by controlling the position at which the control signal is applied to the thyristor 3. The ignition circuit 5 used in the present invention may be one that suddenly changes the primary current of the ignition coil 1 to perform the ignition operation by operating a primary current control switch, and other types such as a current cut-off type ignition circuit may be used. ignition circuit may be used.

In the power supply circuit 15, the exciter coil 6
In the half cycle induced by the voltage in the direction of the dashed arrow shown in the figure, the power supply capacitor 14 is charged to the polarity shown in the figure through the diode 13. When the output of the exciter coil 6 in the direction of the dashed arrow reaches a certain value, the Zener diode 11 becomes conductive, the thyristor 10 becomes conductive, and the output of the exciter coil 6 is bypassed from the capacitor 14. Therefore, the capacitor 14 is always charged to a constant voltage, and this capacitor is used as a power source for a control circuit to be described later.

An ignition position control circuit 20 is provided to control the ignition position according to the engine speed (rpm). This control circuit includes a signal coil 23 installed in a signal generator that rotates synchronously with the engine, and this signal coil 23 outputs one cycle of the signal e _s (see Fig. 2C) during one rotation of the engine. . In this embodiment, the signal coil 23 first moves in the direction of the dashed arrow shown in the figure (hereinafter, this half cycle will be referred to as a negative half cycle).
The signal e _s1 is then generated in the direction of the solid arrow shown in the figure (hereinafter, this half cycle will be referred to as a positive half cycle).
A signal e _s2 is generated. One end of this signal coil is grounded, and the other end is connected to the gate of the thyristor 3 through a diode 24. Here, the diode 24 is provided with its cathode located on the cathode side of the thyristor 3, and the positive half cycle signal e _s2 generated after the signal coil 23
is applied as a control signal to the gate of the thyristor 3 through the diode 24.

On the other hand, one end of a resistor 25 is connected to the non-grounded terminal of the power supply capacitor 14, and the other end 25a of the resistor 25 is connected to the diode 2 in the same direction as the diode 24.
6 to the gate of thyristor 3. Resistor 25 and diode 26 are connected to signal coil 2
3 constitutes a signal supply circuit that gives a control signal to the thyristor 3 separately, and when a predetermined condition is met, the control signal is given to the thyristor 3 from the power supply circuit 15 side through the resistor 25 and the diode 26. It's getting old.

The collector of a transistor 27 as a signal supply control semiconductor switch whose emitter is grounded is connected to the other end 25a of the resistor 25, and the base of the transistor 27 is connected to the non-grounded terminal of the power supply capacitor 14 through a resistor 28. There is. The base of the transistor 27 is connected to the cathode of the diode 29 whose anode is grounded, and is also connected to the anode of the diode 30.
The cathode of the signal coil 23 is connected to the non-ground terminal of the signal coil 23. The transistor 27 is made conductive by the base current applied from the power supply circuit 15 through the resistor 28 during periods other than the period in which a negative half-cycle signal is generated in the signal coil 23, and the control signal applied from the power supply circuit 15 through the resistor 25 is grounded. It flows to the side and bypasses from the thyristor 3. During the period when the signal coil 23 outputs a negative half-cycle signal, the base and emitter of the transistor 27 is reverse biased, so the transistor 27 is cut off, and the control signal supplied through the resistor 25 is applied to the thyristor 3. is allowed.

As mentioned above, during the period when the transistor 27 is in the cut-off state (the period during which the signal coil 23 generates a negative half-cycle signal), the resistor 25 and the diode 26
However, in order to provide further conditions to the supply of this control signal to provide advance angle characteristics and retard angle characteristics, the first capacitor 31 and the second capacitor 32 are charged and discharged. A circuit is provided for controlling the supply position of the control signal using the . That is, one end of the first capacitor 31 is grounded, and the other end of the first capacitor 31 is connected to the cathode of the diode 33. The anode of the diode 33 is connected to the source of a field effect transistor (hereinafter referred to as FET) 35 through a resistor 34, and the drain of the FET 35 is connected to the non-grounded terminal of the power supply capacitor 14.
The gate of the FET 35 is connected to the anode of the diode 33, and the FET 35 and the resistor 34 constitute a constant current circuit. The drain of FET 36 is also connected to the cathode of diode 33,
The source of FET 36 is connected to the collector of transistor 38 through resistor 37. FET3
The gate of FET 6 is connected to the connection point between resistor 37 and the collector of transistor 38, and these FET 36 and resistor 37 also constitute a constant current circuit. The collector of transistor 38 is also connected to the anode of diode 33, and its emitter is grounded. A series circuit of resistors 39 and 40 is connected in parallel between the collector and emitter of the transistor 27, and the base of the transistor 38 is connected to the connection point of the resistors 39 and 40. transistor 3
When the transistor 27 is in the cut-off state, a base current is applied through the resistors 25 and 39 to turn the transistor 8 into a conductive state, and when the transistor 27 is turned on, the transistor 8 is turned into a cut-off state. The first capacitor 31 is charged with a constant current by the power supply circuit 15 through the FET 35, the resistor 34, and the diode 33 to the illustrated polarity. Further, when the transistor 27 is cut off and the transistor 38 is turned on, the first capacitor 31 is turned off.
A constant current is discharged through the FET 36, the resistor 37, and the transistor 38. During this discharge, the current supplied from the power supply circuit 15 through the FET 35 and the resistor 34 is bypassed from the first capacitor 31 through the transistor 38, so that it does not affect the discharge of the first capacitor 31. FET36,
The resistor 37 and the transistor 38 constitute a discharge circuit for the first capacitor 31.

Furthermore, a Zener diode 42 is connected in parallel to both ends of the power supply capacitor 14 via a resistor 41.
A first reference voltage V _r1 is obtained across the Zener diode 42 . This first reference voltage is inputted to the first comparator circuit 43 together with the terminal voltage V _c1 of the first capacitor 31, the two voltages are compared, and the output terminal 43a of the first comparator circuit 43
is, the terminal voltage V _c1 of the first capacitor 31 is the first
The terminal voltage V _c1 of the first capacitor 31 becomes the ground potential when it is larger than the reference voltage V _r1 of the first capacitor 31.
When the voltage drops below the reference voltage _Vr1 , the potential becomes high.
The output terminal 43a of this first comparison circuit 43 is connected to the anode of the diode 26, and when the output terminal 43a of this comparison circuit is at ground potential, the supply of the control signal to the thyristor 3 is blocked, and the output terminal The control signal is allowed to be supplied to the thyristor 3 when the potential of the thyristor 43a becomes high.

The second capacitor 32 is also connected to the non-ground terminal of the power supply capacitor 14 through a constant current circuit consisting of an FET 44 and a resistor 45 and a diode 46, and is charged with a constant current by the output of the power supply circuit 15. . A Zener diode 48 is connected to both ends of the power supply capacitor 14 via a resistor 47.
are connected in parallel, and the second reference voltage V _r2 obtained across the Zener diode 48 is applied to the second comparator circuit 4 together with the terminal voltage V _c2 of the second capacitor 32.
9 is entered. The output terminal 49a of the second comparison circuit 49 is the terminal voltage V of the second capacitor 32.
It becomes a ground potential when _c2 is smaller than the second reference voltage V _r2 , and becomes a high potential when the terminal voltage V _c2 of the second capacitor becomes equal to or higher than the second reference voltage V _r2 . The output terminal 49a of this comparison circuit 49 is connected to the anode of the diode 26, and the output terminal 49a
The control signal is allowed to be supplied to the thyristor 3 when the voltage becomes a high potential.

In the above embodiment, the control signal is given to the thyristor 3 in any of the following cases.

(a) When a positive half-cycle signal is induced in the signal coil 23.

(b) The transistor 27 is in a cutoff state, and the output terminal 43a of the first comparator circuit 43 and the second
When the output terminal 49a of the comparison circuit 49 is at a high potential.

In order to instantly discharge the charges in the first and second capacitors 31 and 32 and reset both capacitors, a transistor 50 whose emitter is grounded is provided. It is connected to the non-ground side terminals of capacitors 31 and 32 of No. 2. Further, the base of the transistor 50 is connected to a voltage dividing point of a voltage dividing circuit consisting of resistors 53 and 54 connected in parallel to both ends of the signal coil 23, and the transistor 50, diodes 51 and 52, and resistors 53 and 5
4 constitutes a reset circuit.

Next, according to the signal waveform diagrams in FIGS.
The operation of the illustrated embodiment will be explained. Assuming that the magnet generator in which the exciter coil 6 is arranged has four poles and is directly connected to the output shaft of the engine, the exciter coil 6 has two cycles per revolution as shown in Figure 2A. is induced by an alternating current voltage V _e . The negative half cycle of this voltage is originally a waveform shown by a broken line in the figure, but in the above embodiment, when the voltage of the negative half cycle reaches a level that makes the Zener diode 11 conductive, the thyristor 10 becomes conductive. Since the voltage is short-circuited, the waveform becomes limited to a certain voltage as shown by the solid line in the figure. When the positive half-cycle voltage of the exciter coil 6 rises at a position before the top dead center TDC of the engine by an angle θ ₀ , the capacitor 2 is charged to the polarity shown through the diode 7, and its terminal voltage V _c becomes Figure 2B
Changes as shown in . The signal coil 23 generates a negative direction signal e _s1 at the angle θ 1 before the top dead center, which is set near the fall of the second positive output of the exciter coil 6, and then at the angle θ ₁ before the top dead center. At position ₂ , a forward direction signal e _s2 is generated. Engine rotation speed N (rpm) changes from idling rotation speed N ₁ to set value
In the low speed region up to N ₂ (>N ₁ ), the negative direction signal e _s1 output from the signal coil 23 does not reach a level that can cut off the transistor 27.
Transistor 27 is in a conductive state. Therefore, in the low speed region of the engine, the resistor 2 is connected from the power supply circuit 15 side.
No control signal is applied to the thyristor 3 through the resistor 25 and the diode 26, and any current applied from the power supply circuit through the resistor 25 is bypassed from the thyristor 3 through the transistor 27.
Next, the positive direction signal e _s2 of the signal coil ₂₃ generated at an angle θ 2 reaches a peak at a position of an angle θ ₃ before top dead center, and when this peak value reaches the gate trigger level of the thyristor 3, the thyristor 3 conducts. At this time, the charge on capacitor 2 increases to thyristor 3.
The electric current is discharged through the primary coil 1a, and an ignition operation is performed. Since the positive direction signal e _s2 of the signal coil 23 increases as the engine speed increases from N ₁ to N ₂ , the phase at which the positive direction signal e _s2 reaches the trigger level of the thyristor 3 is As shown in FIG. 3, it advances little by little as the rotational speed increases. If the signal width of the positive direction signal e _s2 of the signal coil 23 is narrowed, the fluctuation range of the ignition position in this low speed region is small.

When the engine speed N reaches the set value _N2 , the negative direction signal e _s1 of the signal coil 23 is output to the transistor 27.
Transistor 27
is blocked. At this time, the collector-emitter voltage of the transistor 27 changes as shown in FIG. 2D.

On the other hand, the first and second capacitors 31 and 32
is charged with a constant current by the power supply circuit 15 through the FETs 35 and 44, and is instantaneously discharged to approximately zero by the conduction of the transistor 50 at the rise of the positive direction signal e _s2 . As described above, when the rotation speed reaches the set value N ₂ and the transistor 27 is cut off, the transistor 38 becomes conductive, so that the first capacitor 31 is discharged with a constant current through the FET 36. Therefore, as shown in FIG. 2E, the waveform of the terminal voltage V _c1 of the first capacitor 31 in the region of rotational speed N ₂ or more rises at a constant slope from the position of angle θ ₂ , and then rises at an angle of θ ₁ It descends at a constant slope from to θ ₂ until it reaches the charging start position θ ₂
The waveform returns to zero at the next angle θ ₂ corresponding to the position rotated by 360°, and the waveform repeats. On the other hand, since the second capacitor 32 is only reset by the transistor 50, the waveform of the terminal voltage V _c2 of this capacitor 32 changes at an angle θ ₂ as shown in FIG. 2G.
The waveform rises at a constant slope and returns to zero at a position rotated 360 degrees. The engine speed N is the set value
When N ₂ is exceeded, the terminal voltage V _c1 of the first capacitor 31 becomes equal to or lower than the first reference voltage V _r1 at a position θ _y whose phase is advanced from the angle θ ₂ , and the second
As shown in FIG. F, the output terminal 43a of the first comparator circuit 43 becomes high potential at the position of θ _y . This θ
The position of _y advances as the engine speed increases. In this embodiment, the rotation speed N is the set value N ₃
(>N ₂ ), the position of this θ _y becomes the angle θ
It is set to match position ₁ .

On the other hand, the terminal voltage V _c2 of the second capacitor 32 is
At the position of the angle θ _x before the top dead center, the voltage becomes equal to or higher than the second reference voltage V _r2 , and as shown in FIG. 2H, at the position of this _θ . The position of θ _x lags toward top dead center TDC as the engine speed increases. In this example, when the rotation speed N reaches the set value N ₄ (>N ₃ ), the position of θ _x matches the position of the angle θ ₁ , and the rotation speed N reaches the set value N ₅ (>N ₄ ). When the angle θ x is reached, the position of θ _x coincides with the position of the angle θ ₂ .

Because of the above settings, in the medium to high speed region where the engine speed N is in the range of N ₂ ≦N≦N ₃ , the resistor 2 is connected from the power supply circuit 15 side at the angle θ _y position.
5 and the diode 26, the condition is satisfied that the control signal is given to the thyristor 3, and this angle θ _y
The ignition operation is performed at the position. The position of θ _y advances as the rotation speed increases, and the set rotation speed
When it reaches N ₃ , it reaches the position of angle θ ₁ before top dead center. As the rotational speed further increases, the position of θ _y advances further, but since the transistor 27 is conductive at a position further advanced than the position of the angle θ ₁ , no control signal is applied to the thyristor 3 . Therefore, the ignition position advances only to the position at the angle θ ₁ , and ignition is performed at the position at the angle θ ₁ from the set rotational speed N ₃ to N ₄ . Engine speed is set value N ₄
, the output terminal 49 of the second comparator circuit 49
The position θ _x where a rises to a high potential coincides with θ ₁ , and as the rotation speed further increases, the position of θ _x further lags toward the top dead center, so a control signal is sent from the power supply circuit 15 to the thyristor 3. The position where the condition given is satisfied is the position of θ _x , and the ignition operation is performed at this position. Therefore, the set rotation speed
In the range from N ₄ to N ₅ , the ignition position becomes delayed as the rotational speed increases. The number of revolutions is the set number of revolutions N ₅
As described above, when the position of θ _x becomes closer to the top dead center than the position of the angle θ ₂ before top dead center, θ _x
A control signal is applied to the thyristor 3 by the positive direction signal e _s2 of the signal coil 23 at the position of angle θ ₂ before the control signal is applied from the power supply circuit 15 at the position. Therefore, the set rotation speed
The ignition position in the region above _N5 is fixed at the position of _θ2 . Through the above operations, advance/retard angle characteristics as shown in FIG. 3 can be obtained.

In the above embodiment, the maximum advance angle position θ ₁ is determined by the rising position of the negative direction signal e _s1 of the signal coil 23, so by appropriately setting the magnetic pole structure of the signal generator and its mounting position, the maximum advance angle position θ
₁ can be easily set at a desired position.
And if we keep the structure of the signal generator constant,
This maximum advance angle position _θ1 remains unchanged, and there is no problem that occurs when the maximum advance angle position varies depending on the characteristics of the generator as in the conventional case. Moreover, in the high speed range of the engine, the ignition position can be maintained at the maximum advance position without being delayed. Furthermore,
The ignition position (maximum retard position) θ ₁ at the end of the retard is also determined by the rising position of the positive direction signal of the signal coil, so the maximum retard position can also be kept constant, and the ignition position is too late. can be prevented. Further, since the fluctuation range of the ignition position in the low speed region can be suppressed to a small value, the startability of the engine can be improved. Furthermore, each set rotation speed can be easily adjusted by appropriately setting the charging time constants of the first and second capacitors and the levels of the first and second reference voltages.

In the above embodiment, the power supply circuit 15 using the negative direction output of the exciter coil is used as a power supply for supplying a control signal to the thyristor (primary current control switch) and as a power supply for charging the first and second capacitors. , a battery can also be used as a power source for these.

In the above embodiment, the second reference voltage is set lower than the first reference voltage, but if the terminal voltage of the second capacitor is set higher than the terminal voltage of the first capacitor, the second reference voltage is set lower than the first reference voltage. The reference voltage may be equal to or greater than the first reference voltage.

As described above, according to the present invention, it is possible to easily adjust the advance and retard characteristics, and also to reduce fluctuations in the ignition position at low speeds, thereby improving engine startability. . Further, since the ignition position can be fixed at the maximum advance angle position in a predetermined range in the high speed range, the engine can be operated stably and its performance can be maximized. Furthermore, since the maximum amount of retardation in the retardation region can be kept constant, it is possible to prevent the engine operation from becoming unstable due to too much delay in the ignition position.

[Brief explanation of the drawing]

Fig. 1 is a connection diagram showing an embodiment of the present invention, Fig. 2 A to H are signal waveform diagrams of each part of Fig. 1, and Fig. 3 shows the lead/retard angle characteristics obtained by the embodiment of Fig. 1. It is a diagram showing an example. 1...Ignition coil, 3...Thyristor, 5...
Ignition circuit, 6... Exciter coil, 15... Power supply circuit, 23... Signal coil, 27... Transistor, 31... First capacitor, 32... Second
capacitor, 35, 36, 44...FET, 3
8... Transistor, 42, 48... Zener diode, 43... First comparison circuit, 49... Second comparison circuit.

Claims (1)

[Claims] 1. In a non-contact ignition device for an internal combustion engine that performs ignition operation by controlling the primary current of an ignition coil by a primary current control switch operated by a control signal given at the ignition position of the engine, one rotation of the internal combustion engine is provided. A signal coil provided to generate a one-cycle signal per cycle and supply a half-cycle signal generated later to the primary current control switch as the control signal, and a control signal provided by the signal coil is separate. a signal supply circuit for supplying a control signal to the primary current control switch; and a signal supply circuit configured to bypass the control signal supplied from the signal supply circuit from the primary current control switch when conductive. a signal supply control semiconductor switch coupled to the signal coil so as to be kept in a cut-off state by a half-cycle signal generated at the tip of the coil; a discharge circuit that discharges the first capacitor at a constant time constant during a half cycle preceding the output of the signal coil; and a reset circuit for discharging a second capacitor; and a reset circuit that compares a terminal voltage of the first capacitor with a first reference voltage, and when the terminal voltage of the first capacitor is higher than the first reference voltage, the reset circuit discharges the second capacitor. Preventing the control signal from being applied from the signal supply circuit and allowing the control signal to be applied from the signal supply circuit when the terminal voltage of the first capacitor falls below the first reference voltage. a first comparator circuit, which compares the terminal voltage of the second capacitor with a second reference voltage, and when the terminal voltage of the second capacitor is lower than the second reference voltage, the terminal voltage of the second capacitor is lower than the second reference voltage; a second comparator circuit that prevents the control signal from being applied and allows the control signal to be applied from the signal supply circuit when the terminal voltage of the second capacitor becomes equal to or higher than the second reference voltage; A non-contact ignition device for an internal combustion engine, characterized by comprising: