JPH0756244B2 - Ignition device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for an internal combustion engine, and more particularly, to limiting a primary current of an ignition coil to a predetermined value for a period of time limited to the predetermined value. The present invention relates to an ignition device for an internal combustion engine having a function of controlling the energization time of an ignition coil according to the above, and a function of permitting energization of the ignition coil for a predetermined time.

[Conventional technology]

 Conventionally, this type of device has a structure shown in FIG.

In the conventional device shown in FIG. 5, the primary current of the ignition coil 10 is detected by the resistor 30, and the detected voltage is input to the current limiting circuit 50, and the current limiting circuit 50 sets the primary current value to a predetermined value. When it reaches, by controlling the drive circuit 40 of the power transistor 20, the base current of the power transistor 20 is controlled, and the primary current is limited to a predetermined value as shown by the current waveform in FIG. Further, the current limiting circuit 50 outputs a pulse signal (FIG. 6h) during the period in which the primary current is limited to a predetermined value to the closing angle control circuit 60. An ignition signal (Fig. 6a) is input to the closing angle control circuit 60, and the optimum energization time of the ignition coil 10 is calculated according to the pulse width of the pulse signal shown in Fig. 6h based on this ignition signal. The signal of FIG. 6d is output. The closing angle control circuit 60 includes at least two capacitors for calculating the energization time. One is Fig. 6b.
This is for creating the ramp wave shown in Fig. 6, and the other one is the pulse width in Fig. 6h (pulses in the current limited period).
For integrating and storing (FIG. 6c). The calculation of the optimum energization time is performed using the waveforms of the two capacitors. The output signal (FIG. 6d) of the closing angle control circuit 60 is input to the energization prevention circuit 70, and the energization prevention circuit 70 is operated as shown in FIG. 6f.
The signal of is output. The energization prevention circuit 70 includes at least one capacitor, and the capacitor is charged, for example, when energization of the ignition coil 10 is started, and is discharged (reset) at the ignition timing (Fig. 6e). The energization prevention circuit 70 outputs a signal f for forcibly shutting off the primary current at a point where the charging voltage of the capacitor reaches a predetermined voltage at point i in FIG. 6 when a signal is input to continue energization. The primary current is cut off.

[Problems to be solved by the invention]

In this conventional device, calculation is performed using at least three capacitors in order to achieve the intended function, and in particular, the capacitors for obtaining the waveforms in FIGS. 6c and 6e require relatively large capacitance values. Therefore, the device is large and costly.

Further, in order to reduce the number of capacitors, it has been considered to use the energization blocking capacitor also as a malfunction prevention capacitor having a relatively small capacity (for example, Japanese Patent Laid-Open No. 60-
No. 212672), however, the number of capacitors on the closed angle control circuit side having a large capacitance could not be reduced at all.

Therefore, an object of the present invention is to provide a small-sized and low-cost device by sharing a large-capacity closed-angle control circuit side capacitor and an energization blocking capacitor in a single capacitor.

[Means for solving problems]

To achieve the above object, the present invention provides: a current limiting means for limiting the primary current of the ignition coil to a predetermined value; a first capacitor for producing a ramp wave synchronized with the rotation of the internal combustion engine; and the current limiting means. A second capacitor that integrates a time pulse in which the primary current of the ignition coil is limited to a predetermined value by means of a ramp wave voltage created by the first capacitor, and the second capacitor is charged. A closing angle control circuit that controls the energization time so that the time during which the primary current is limited to a predetermined value is a predetermined time by comparing a voltage value related to the generated voltage; An energization blocking unit that permits energization of the next current for a predetermined time; and when the charging voltage of the second capacitor of the closing angle control circuit reaches a set value, the second capacitor of the closing angle control circuit. And a waveform switching means for switching the charging / discharging waveform from the closing angle control waveform of the closing angle control circuit to the energization time detection waveform of the energization blocking means.

[Action]

 The operation of the above-described configuration of the present invention will be described.

The closing angle control circuit performs energization time control so that the time during which the primary current of the ignition coil is limited to a predetermined value is a predetermined time. When the charging voltage of the second capacitor of the closing angle control circuit reaches the set value, the waveform switching means energizes the charging / discharging waveform of the second capacitor of the closing angle control circuit from the closing angle control waveform of the closing angle control circuit. Switching to the conduction time detection waveform of the blocking means, the conduction blocking means permits the conduction of the primary current for a predetermined time based on the conduction time detection waveform,
After a lapse of a predetermined time, energization is stopped.

As described above, in the present invention, when the charging voltage of the second capacitor of the closing angle control circuit reaches the set value, the charging / discharging waveform of the second capacitor of the closing angle control circuit is energized from the closing angle control waveform of the closing angle control circuit. Since the waveform is switched to the conduction time detection waveform of the blocking means, the second capacitor of the closing angle control circuit is used both for closing angle control and for blocking conduction.

〔Example〕

 A first embodiment of the present invention is shown in FIG.

In FIG. 1, 1 is an ignition coil and 2 is an ignition coil 1.
The power transistor 3 for cutting off the secondary current is a resistor for detecting the primary current of the ignition coil 1. Reference numeral 4 denotes a shaping circuit to which a signal synchronized with the rotation of the engine is input and which performs noise removal and the like. Reference numeral 5 is a closing angle control circuit for calculating an optimum energization time of the ignition coil 1 based on the ignition signal from the shaping circuit 4 according to the pulse width of the current restriction period from the current restriction circuit 7 and outputting an energization pulse signal. Ignition coil 1
An energization blocking circuit for preventing the energization of the ignition coil 1 for a predetermined time or longer, a current limiting circuit 7 for limiting the primary current of the ignition coil 1 to a predetermined value, and a drive circuit 8 for controlling the power transistor 2. is there.

Then, 501 to 512 of the closing angle control circuit 5 are resistors and 513 to 524.
Is a transistor, 525 is a first capacitor for charging and discharging by the ignition signal from the shaping circuit 4 to create a ramp wave, and 526 is for integrating and storing the pulse width of the current limiting period from the current limiting circuit 7. Being a capacitor,
The second capacitor is also a capacitor for obtaining time information for creating a pulse for a predetermined time in the energization prevention circuit 6. 527 is a comparator for determining the energization time by comparing the first and second capacitor voltages. 528 is an OR gate, 529 is the first capacitor 525
Is a constant current source for charging the second capacitor 526 with a constant current, 530 is a constant current source for discharging the second capacitor 526 with a constant current, and 531 and 532 are constant current sources for charging the second capacitor 526 with a constant current. 533 and 534 are diodes, and 535 is a resistor.

In the energization prevention circuit 6, 601 to 605 are resistors, 606 is a transistor, and 607 is a comparator for comparing the charging voltage of the second capacitor 526 with a predetermined voltage value to obtain a pulse for a predetermined time. 608 is a diode. 701 of current limit circuit 7
˜706 are resistors, 707 and 708 are transistors, and 709 is a comparison circuit for comparing the primary current value detected by the resistor 3 with a predetermined voltage to obtain a signal for limiting the primary current to a predetermined value. In the drive circuit 8, 801 to 805 are resistors and 806 to 808 are transistors.

Next, the operation of the first embodiment shown in FIG. 1 will be described. FIG. 2 shows the operation waveforms of the portions marked with symbols A to J in the embodiment shown in FIG. The ignition signal from the shaping circuit 4 (FIG. 2A) causes the transistor 513 to turn on and off, and when the transistor 513 turns off, the first capacitor 52 is turned on.
5 is charged with a constant current by the current i ₁ of the constant current source 529. When the transistor 513 is turned on, the electric charge charged in the first capacitor 525 is rapidly discharged, and the ramp wave shown in FIG. 2B is created. This ramp wave and the charging voltage of the second capacitor 526 are compared by the comparator 527 to obtain the signal of FIG. 2F.
The OR of the signal of FIG. 2F and the signal of FIG. 2A is OR gate
Taken at 528, turn on and off the transistors 514 and 515, Fig. 2
During the period T ₁ , the transistor 515 is turned off, the constant current i ₂ of the constant current source 530 flows through the transistor 516, and the transistor 517 forming a current mirror with the transistor 516 has the constant current i 2.
_{By 2} , the electric charge charged in the second capacitor 526 is discharged with a constant current. At this time, the primary current of the ignition coil 1 is in the cut-off state, and the transistor 708 of the current limiting circuit 7 turns off.
It is FF, and the transistors 518 and 519 are ON. Therefore, the second capacitor 526 is not charged by the constant currents i ₃ and i ₄ of the constant current sources 531 and 532. Next, the comparator 527
Is inverted and the comparator output outputs a low level,
The transistor 515 turns on and the second capacitor 526 due to i ₂
Discharge is stopped. At this time, the transistors 807 and 808 of the drive circuit 8 are turned off, the power transistor 2 is turned on, and the conduction of the primary current of the ignition coil 1 is started. This primary current is detected by the resistor 3 (FIG. 2H), and the resistors 702 and 703 of the current limiting circuit 7 and the terminal 9 connected to the constant voltage power source (not shown) are connected.
The predetermined voltage value determined by the constant voltage value of (I in FIG. 2) is compared by the comparator 709, and when the primary current value reaches the predetermined voltage value, the output voltage of the comparator 709 shifts from the low level to the high level, Transistors 707, 806, 808 are turned on, reducing the base current of power transistor 2,
The coil primary current is limited to a predetermined value. While the primary current is limited to the predetermined value, the transistor 708 is ON.
Then, a current limiting period pulse (J in FIG. 2) is output. Figure 2 period T ₃ primary current of the ignition coil 1 is a period from the start of energization until the current limit, the transistor 515,
518 and 519 are in the ON state, and the second capacitor 526 is neither charged nor discharged. Next, during the period T _{4 in} FIG. 2 during which the primary current of the ignition coil 1 is current limited, the transistor
515 turns on, transistors 518 and 519 turn off, and the second
The capacitor 526 is charged by the constant currents i ₃ and i ₄ of the constant current sources 531 and 532, and the above operation is repeated to obtain the waveform of FIG. 2C. That is, the second capacitor 526 is charged (i ₃
The voltage of the second capacitor 526 is feedback-controlled so that the time T _{4 in} FIG. 2 becomes a predetermined time by the charge balance between the amount of + i ₄ ) charge and the amount of discharged (i ₂ ) charge and the optimum energization time is always set. It has gained.

Here, due to some abnormality such as stop of the engine, FIG.
When the energization signal shown in (1) outputs a signal that keeps the energized state, the second capacitor 526 causes i ₃ + i ₄ by the above operation.
Is charged by the constant current (FIG. 2 T ₅ periods) capacitor voltage increases, the predetermined voltage determined by resistors 509,508 (second
When (D) is reached, the voltage on the anode side of the diode 534 is clamped by the transistor 520 to a predetermined voltage determined by the voltage of FIG. 2D. That is, the constant current i ₄ all flows through the transistor 520. Therefore, after the charging voltage of the capacitor 526 reaches the voltage shown in FIG. 2D, the charging is continued by the constant current i ₃ , and when it reaches the predetermined voltage determined by the resistors 601 and 602 of the conduction blocking circuit 6, the comparator 607 is inverted and the second
The signal of FIG. G is output. The signal shown in FIG. 2G is applied to the comparator 709 of the current control circuit 7, and becomes a level higher than a predetermined voltage value (FIG. 2I) for normal comparison as shown in FIG. 2H, so that the transistors 707, 806, 808 are provided.
Switches from the active state to the saturated state, the power transistor 2 is turned off, and the primary current of the ignition coil 1 is cut off. If the ignition signal (FIG. 2A) from the shaping circuit 4 is switched from the low level to the high level while maintaining this cutoff state, the transistor
524 turns off, and the base potential of transistor 521 is shown in Fig. 2D.
The transistor 521 rapidly discharges until the charging voltage of the second capacitor 526 becomes substantially the predetermined voltage shown in FIG. 2D, and the discharge by the transistor 521 is stopped when the predetermined voltage is reached. After that, the above operation is performed.

Third, a second embodiment of the present invention will be shown. 1-4, 7, 8 is the first
The description is omitted because it is the same as the figure. Reference numeral 5 is a closing angle control circuit, 541 to 545 are resistors, 546 to 553 are transistors, and 554.
Is a first capacitor for generating a ramp wave, and 555 integrates and stores a pulse during a period in which the primary current of the ignition coil is current-limited and stores time information for permitting energization of the ignition coil 1 for a predetermined time. A second capacitor for obtaining,
556 to 559 are constant current sources, 560 is the first capacitor 554 and the second
Comparing the voltage with the capacitor 555 of, the comparator for obtaining the conduction time pulse, 561 for the comparator, 562,563 for the OR gate, 564,565 for the inverter, 566 for the flip-flop,
567 is a diode. 6 is an energization prevention circuit, 610
~ 612 is a resistor, 613 is an inverter, 614 is a transistor, 6
Reference numeral 15 is a comparator that compares the charging voltage of the second capacitor 555 with a predetermined voltage and outputs a pulse for a predetermined time, 616 is an AND gate, and 617 is an OR gate.

Next, the operation will be described. FIG. 4 shows operation waveforms of various parts of the embodiment shown in FIG. The ignition signal (FIG. 4A) from the shaping circuit 4 charges and discharges the first capacitor 554 to obtain the ramp wave of FIG. 4B. Second condenser 55
5 is a constant current discharge by the constant current i ₅ of the constant current source 557 in the period T _{1 in} FIG. 4, stops charging and discharging in the period T ₃ , and a constant current source in the period T ₄
It is charged with a constant current i _{6 of} 558 (K in FIG. 4). When the engine is operating normally, the above operation is repeated as in the first embodiment, and the second capacitor 555 is discharged by i ₅ and i
Depending on the charge balance of charging by ₆ , the intersection with the ramp wave moves and the optimum energizing time pulse is obtained (Fig. 4 N).

Next, when the energization signal shown in FIG. 4N outputs a signal that maintains the energized state due to some abnormality such as engine stop, the second capacitor 555 causes the constant current i ₆ by the above-described operation.
When it reaches a predetermined voltage (L in FIG. 4) determined by the resistors 544 and 545, the comparator 561 is inverted and the flip-flop 566 is set. When the flip-flop 566 is set, the output of the flip-flop 566 becomes the waveform of FIG. 4P, the transistor 553 is turned on, and i ₆
At the same time, charging of the second capacitor 555 due to is stopped, the transistor 552 is turned off, and the second capacitor 555 is discharged by the constant current i ₇ of the current source 559. The second capacitor 555
When it is discharged at i ₇ and the capacitor voltage is discharged to a predetermined voltage determined by the resistors 610, 611, 612, the comparator 615 is inverted and the signal of FIG. 4Q is obtained. The output of the comparator 615 and the output of the flip-flop 566 are ANDed to obtain the signal of FIG. 2R, and the output signal of the comparator 560 (N of FIG. 4) is ORed to obtain the signal of FIG. A signal is obtained, and the power transistor 2 is forcibly shut off at the timing shown in FIG. 4V by this signal, and this state is maintained. Next, when the comparator 560 switches to a signal that cuts off the energization of the ignition coil 1, the flip-flop 566 is reset and the waveforms of the respective parts become the waveforms shown in FIG. 4, and the subsequent operation is performed by the above-described operation.

〔The invention's effect〕

As described above, the present invention integrates and stores the first capacitor for creating the ramp wave for controlling the energization time of the ignition coil and the pulse during the period in which the primary current of the ignition coil is limited to a predetermined value. Only by providing the second capacitor for the purpose, the optimum energization time control similar to that of the conventional device can be performed, and when the energization is continued, the energization of the ignition coil can be forcibly blocked after a predetermined time. Therefore, there is an excellent effect that a small-sized and low-cost device can be provided.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a first embodiment of the device of the present invention, and FIG. 2 is a corrugated part for explaining the operation of the device shown in FIG.
FIG. 3 is an electric circuit diagram showing a second embodiment of the device of the present invention, and FIG. 4 is a waveform diagram of each part used for explaining the operation of the device shown in FIG.
FIG. 5 is an electric circuit diagram showing a conventional device, and FIG. 6 is a waveform diagram of each part used for explaining the operation of the device shown in FIG. 1 ...... Ignition coil, 5 ... Closed angle control circuit, 6 ... Current blocking circuit, 7 ... Current limit circuit, 520 ... Transistor, 525,554
...... First capacitor, 526,555 …… Second capacitor, 5
61,607,615 …… Comparator, 566 …… Flip-flop.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kazuhiro Yamada 1-1, Showa-cho, Kariya city, Aichi Nihon Denso Co., Ltd. (56) Reference JP-A-57-204630 (JP, A)

Claims (5)

[Claims] 1. A current limiting means for limiting a primary current of an ignition coil to a predetermined value, a first capacitor for producing a ramp wave synchronized with the rotation of an internal combustion engine, and a first limiting means for the ignition coil by the current limiting means. A second capacitor for integrating a time pulse in which the next current is limited to a predetermined value, and has a relationship between the ramp wave voltage created by the first capacitor and the voltage charged in the second capacitor. A closing angle control circuit that performs energization time control so that the time during which the primary current is limited to a predetermined value is a predetermined time by comparing with a voltage value, and energization of the primary current of the ignition coil is predetermined. When the charging voltage of the second capacitor of the closing angle control circuit reaches the set value, the charging / discharging waveform of the second capacitor of the closing angle control circuit is changed to the closing angle. Ignition apparatus for an internal combustion engine and a waveform switching means for switching from close angle control waveform to the conduction time detection waveform of the current blocking means of the control circuit. 2. The waveform switching means comprises current reducing means for reducing the current of the second capacitor when the charging voltage of the second capacitor reaches a first set value, and the energization blocking means comprises The charging voltage of the second capacitor is the second
2. The ignition device for an internal combustion engine according to claim 1, further comprising: a comparison unit that generates an output signal for cutting off the energization of the primary current when the set value is reached. 3. An output signal for interrupting the primary current conduction of the comparing means is applied to an input side of the current limiting means, and the current limiting operation by the current limiting means causes the first
The ignition device for an internal combustion engine according to claim 2, wherein the secondary current is cut off. 4. The storage means for storing the waveform switching means when the charging voltage of the second capacitor exceeds a first set value, and the second capacitor when a storage output is generated in the storage means. Charging / discharging reversing means for starting the discharge of the second capacitor, and the energization blocking means is configured so that when the discharging voltage of the second capacitor becomes equal to or lower than a second set value set to a value lower than the voltage during the closing angle control. The ignition device for an internal combustion engine according to claim 1, further comprising a comparison unit that generates an output signal for cutting off the energization of the primary current. 5. The charging / discharging waveform of the second capacitor, when the charging voltage of the second capacitor reaches a set value which is set to a value exceeding a change range during the closing angle control. 2. The ignition device for an internal combustion engine according to claim 1, wherein is switched from a closing angle control waveform of the closing angle control circuit to a conduction time detection waveform of the conduction preventing means.