JPH0192578A - Contactless ignition system for internal combustion engine - Google Patents

Abstract

PURPOSE:To improve the charging efficiency of a capacitor for ignition by repeating a plurality of times cycle for supplying and interrupting short-circuit current for charging coil during a period when a charging coil of an ignition capacitor generates one half-wave voltage. CONSTITUTION:Transient voltage generated in the interruption of short-circuit current in a coil 1 for charging an ignition capacitor of an engine driven AC generator is utilized to charge the ignition capacitor 3 in an ignition circuit 60. Then, the interruption of short-circuit current in the charging coil 1 is controlled by a short-circuit current interruption control circuit 50 and the short- circuit current interruption signal from said circuit 50 is input in a timer circuit 70. After the input of the short-circuit current interruption signal and passage of a set time, a return signal is output to return the interruption control circuit 50 to the initial short-circuit current supply condition. Thus, while the charging coil 1 generates voltage, the supply and interruption of short-circuit current in the charging coil 1 are adapted to be repeated a plurality of times.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a non-contact ignition device for an internal combustion engine, and more particularly, to a non-contact ignition device for ignition of an internal combustion engine, which is an improved ignition capacitor discharge type non-contact ignition device. The present invention relates to a non-contact ignition device for an internal combustion engine including a capacitor charging voltage boosting device.

(Prior Art) This type of conventional non-contact ignition device for an internal combustion engine is designed to use a non-contact ignition device for an internal combustion engine when a substantial short-circuit current passes through a charging coil of an ignition capacitor included in a magnet generator driven by an internal combustion engine. A non-contact ignition device that utilizes the transient voltage generated in the charging coil has been proposed (Japanese Patent Laid-Open No. 58-172
No. 463).

However, with this prior art device, the ignition capacitor could only be charged once per half wave of the voltage generated by the charging coil of the ignition capacitor. However, during the generation period of one half wave of the voltage generated by the charging coil of the ignition capacitor, there remains a margin period in which the ignition capacitor can be charged multiple times. The present invention has been made with the intention of making effective use of this slack period.

(Problems to be Solved by the Invention) The present invention solves the problem of the generation period of one half wave (hereinafter, the case where a positive half wave is used as an example) of the voltage generated by the charging coil used to charge the above-mentioned ignition capacitor. Within,
Even after the ignition capacitor is charged by the transient voltage generated by interrupting the short-circuit current of the first charging coil, the same cycle of passing and interrupting the short-circuit current of the charging coil and the ignition capacitor each time are performed. The purpose of this invention is to repeat the charging operation multiple times, thereby improving the charging efficiency of the ignition capacitor and increasing the energy of the ignition spark.

(Means for Solving the Problems) In order to achieve the above object, the present invention provides an ignition generator which is included in an alternator driven by an internal combustion engine and which supplies generated voltage as a charging voltage to an ignition capacitor. A capacitor charging coil, an ignition circuit including the ignition capacitor, a timing sensor that generates a crank position detection signal for the internal combustion engine, and a crank position detection signal from the timing sensor that is input to generate an ignition signal at the ignition timing. , an ignition timing control circuit that sends it to the ignition circuit, and a short circuit current cutoff signal that indicates the cutoff of the rising short circuit current, and after a set time has elapsed, the above cutoff control circuit returns to the original short circuit current flow. Provided is a non-contact ignition device for an internal combustion engine that includes a timer circuit for generating a return signal to return to the state.

(Function) In the non-contact ignition device for an internal combustion engine of the present invention, after the initial interruption of the short-circuit current of the charging coil of the ignition capacitor by the interruption control circuit is performed, the charging coil is returned to the tie. Continuing during the generation period of one half-wave generated voltage, the operation of passing and cutting off the short-circuit current in the charging coil is repeated multiple times, and the transient voltage generated in the charging coil when the short-circuit current is cut off is rectified. to obtain the charging current for the ignition capacitor. This improves the charging efficiency of the ignition capacitor.

(Example) The configuration of a device according to an embodiment of the present invention is shown in FIG. 1, which shows an electric circuit of a non-contact ignition device according to the present invention, and FIG. 2, which shows waveforms of electric signals at various parts of the electric circuit in FIG. This will be explained below with reference to. In addition, in the following description, an internal combustion engine will be abbreviated as an engine.

In FIG. 1, reference number @1 indicates a coil for charging a capacitor for ignition of an alternator which is driven by an engine and generates an alternating current voltage . 10 and 11 are charging coil 1
A rectifying diode for each half-wave generated voltage is connected to both ends of the . 60 indicates an ignition circuit, in which 3 is an ignition capacitor, V indicates its charging voltage, and 2 is a reverse current blocking diode. 6 is the SCR for ignition, and 9 is the gate resistance of 5CR6 for ignition. Reference numeral 7 denotes an ignition coil, which supplies the ignition high voltage V 1 generated in the secondary coil to the insulated electrode of the ignition plug 8 . 4 is a timing sensor for detecting the crank position of the engine.

5 is an ignition timing control circuit which inputs the crank position detection signal vS sent from the timing sensor 4, generates an ignition signal at the ignition timing obtained by performing advance angle calculation, and sends it to the ignition circuit 60 for ignition 5CR6. feed to the gate.

50 is the short circuit current i of the charging coil 1. This is a short-circuit current cutoff control circuit that controls the cutoff of the current. Among them, 18 is a transistor pair for short-circuit current flow interruption, 19 is a short-circuit current detection resistor connected in series with transistor pair 18, and 1
7 is the base resistance of transistor pair 18, Vd
indicates the base input voltage of transistor pair 18. 2
2 is a short-circuit current cutoff control transistor; 20 and 21 are voltage dividing resistors that are connected in series and form a voltage vb at their mutual connection point;
connected in parallel to the series connected circuit. Voltage V
b is applied to the base of transistor 22, and
It is supplied to the positive input terminal of a comparator 23 in a timer circuit 70, which will be described later. Further, 38 is a short-circuit current restart control transistor; indicates its base input voltage, and 36 and 37, together with a resistor 35 in a timer circuit 70, which will be described later, represent the base input voltage (2). This is a voltage dividing resistor to form a voltage.

70 indicates a timer circuit, in which 23 is a waveform shaping comparator, 24 and 25 are comparators 23
This is a voltage dividing resistor for forming the reference voltage applied to the negative input terminal of the . 28 has a terminal voltage of ■. is a charging/discharging capacitor, and 27 is its charging resistor. 26 is an output resistance of the comparator 23 and also serves as a discharge resistance of the capacitor 28. 29 is a comparator;
The terminal voltage V 1 of the capacitor 28 is applied to its negative input terminal. 30, 31, 32 and 33 form a voltage dividing resistor circuit for forming a reference voltage applied to the positive input terminal of the comparator 29, and the resistor 32 therein is
This is provided to give hysteresis characteristics to the output voltage f of the comparator 29. 34 is an inverter;
5 is an output bias resistance of the inverter 34.

40 is a DC power supply voltage generation circuit, in which 13 is a DC power supply capacitor whose charging voltage is represented by Vcc;
12 is a backflow blocking diode.

In addition, 16 is an SCR, 14 is a Zener diode, and 15 is a resistor, and these three elements are the DC power supply capacitor 1.
No. 3 charging voltage adjustment circuit is formed. The DC power supply voltage generating circuit 4o is for supplying a stabilized DC power supply voltage to each of the required locations in the electric circuit shown in FIG.

Next, the operation of the apparatus according to the embodiment of the present invention having the above-described configuration will be explained with reference to the electric circuit diagram of the apparatus of the present invention shown in FIG. 1 and the electrical signal waveform diagram of each part shown in FIG.

When a negative half-wave voltage is generated in the ignition capacitor charging coil 1, the power supply capacitor 13 is charged by the charging NN current passing through the path of the coil 1→diode 12→DC power supply capacitor 13→diode 11. When the charging voltage of the power supply capacitor 13 reaches the set value, the charging voltage of the power supply capacitor 13 is detected by the Zener diode 14, and the charging voltage of the power supply capacitor 13 is increased by making 5CR16 conductive and bypassing the charging current. Predetermined set value V. Ill m to keep C.

In addition, a base current flows from the DC power supply capacitor 13 through the resistor 17 while always keeping the base potential Vd of the transistor pair 18 at a high level, so that when the collector voltage is applied to the transistor pair 18, It is in a state where it is turned on at any time.Therefore, when the voltage generated by the positive half wave of the coil 1 rises, the transistor pair 18 turns on, and the transistor pair
Short-circuit current i in coil 1 via the collector-to-emitter path of pair 18. flow. Since the value of the short circuit current at this rising time is not large, the short circuit current i. The voltage drop within the resistor 19 is small, and the value of its partial voltage vb is also small and does not reach the trigger level of the short-circuit current cutoff control transistor 22, so it is turned off. After that, charging coil 1
As the short-circuit current increases by 1°, the voltage drop across the resistor 19 increases, and when the value of its partial voltage vb reaches the trigger level of the transistor 22, the transistor 22 turns on and shunts the base current of the transistor bare 18. Therefore, the transistor bare 18 is immediately turned off and the short circuit current i in the coil 1. cut off. In this way, constant current interruption is performed to control the maximum value of the short circuit current of the coil 1 to a constant value. Note that the magnitude of the voltage V after the short-circuit current is cut off is the divided voltage value of the no-load positive half-wave generated voltage of the coil 1, so the transistor 22 is turned on, and therefore the transistor bare 18 is turned off. keep.

When the short circuit current 1° is cut off, the transient voltage generated in the charging coil 1 causes the charging coil 1 → diode 2 → ignition capacitor 3 → the primary coil of the ignition coil 7 →
The ignition capacitor 3 is charged by the current passing through the path of the diode 10.

When the charging coil 1 is generating a negative half-wave voltage, the voltage V1. becomes a very small negative voltage, and even when the charging coil 1 is generating a positive half-wave voltage, the voltage vb does not become higher than the trigger level of the transistor 22 while the short-circuit current i is flowing therethrough. Therefore, in these cases,
The voltage Vb applied to the positive input terminal of the comparator 23 of the timer circuit 70 is always smaller than the reference voltage applied to the negative input terminal, so the comparator 23 is off, and its output m potential is at zero level. Therefore, the terminal voltage V of the capacitor 28 is also zero volts. In this state, the comparator 29 is in an on state, and its output terminal potential V is at a high level. Therefore, since the inverted output from the inverter 34 becomes zero volts, the base voltage V of the transistor 38 also becomes zero volts, and the transistor 38 remains off.

In the above state, the short circuit current i of the charging coil 1. When the cutoff operation is performed, the partial pressure Vb increased as described above.
is sent to the positive input terminal of the comparator 23, the comparator 23 turns on, and its output terminal becomes high level, so the capacitor 28 is charged by the current passing through the path of DC power supply capacitor 13 → resistor 27 → capacitor 28. is started. As the charging of the capacitor 28 progresses, the voltage at its terminals V 2 increases with time, and when it reaches the reference voltage value at the positive input terminal of the comparator 29, which is determined by the voltage dividing resistors 30, 31, 32 and 33 at this time, the comparator 29 is turned off and the potential vf at its output terminal becomes low level, so the output terminal of the inverter 34 becomes high level, and the base potential of the transistor 38 becomes ■. is set high to provide base current, turning transistor 38 on. Therefore, the base current of transistor 22 is shunted and transistor 22 is turned off.

As a result, the transistor 18 is turned on with the base current flowing again, and the short circuit current 1 of the capacitor charging coil 1
゜ flows. Hereinafter, by repeating the timer operation of the timer circuit 7o and repeating the same operation as above,
During the period when the positive half-wave voltage of the charging coil 1 is generated, the short-circuit current i
. The ignition capacitor 3 is charged many times by repeating the conduction and cutoff of the ignition capacitor 3.

On the other hand, when the transistor 38 is turned on, the comparator 23 is turned off because its positive input voltage vb becomes zero volts, so that the charge in the capacitor 28 is discharged through the ground circuit of the capacitor 28 → resistor 26 → comparator 23.

However, the terminal voltage (■) of the reference voltage 8 at that time of the positive input terminal of the comparator 29 given hysteresis characteristics. until the comparator 29
does not turn on, so transistor 38 remains on during this time, turning off transistor 22 and causing a short circuit current i to flow through transistor 18. Continue the flow of water.

In addition to the above operations, the ignition IIi control circuit 5 receives, for example, a crank position detection signal 8 from the timing sensor 4 that is generated once per revolution of the engine, calculates an appropriate ignition timing, and starts the ignition. Generate a signal. 5CR for ignition
6 is turned on by inputting the ignition signal from the ignition timing control circuit 5, and transfers the charging charge of the sufficiently charged ignition capacitor 3 to the ignition capacitor 3→5CR6→cando grounding circuit of 5CR6→ignition coil 7 The high voltage V2 for ignition generated in the secondary coil of the ignition coil 7 causes an ignition spark to be generated in the ignition plug 8.

In the device of the present invention, especially at low speeds where the positive half-wave generated voltage of the ignition capacitor charging coil 1 is generated for a long time,
Since the number of times of multiple charging is large, the boosting effect of the ignition capacitor is extremely large, but as the engine speed increases, the number of times of multiple charging decreases, so the boosting effect of the ignition capacitor tends to decrease. However, when the engine is running at high speed, the voltage generated by the ignition capacitor charging coil increases, which compensates for the disadvantage of the reduction in boosting effect due to the reduction in the number of times of multiple charging, and furthermore, the reduction in the number of turns of the charging coil. (thick lines), which has the advantage of improving manufacturing efficiency and charging efficiency.

(Effects of the Invention) According to the present invention, the charging coil of the ignition capacitor of the ignition capacitor discharging non-contact ignition device for an internal combustion engine has one
During the period in which two half-wave voltages are being generated, even after the ignition capacitor is charged by the transient voltage generated by interrupting the short-circuit current of the first charging coil, the same short-circuit current of the charging coil continues to flow. By repeating the cycle of current and cutoff and the charging operation of the ignition capacitor performed each time multiple times, it is possible to improve the charging efficiency of the ignition capacitor and provide sufficient energy to the ignition spark. Effects can be obtained.

[Brief explanation of the drawing]

FIG. 1 is an electrical circuit diagram showing the structure of a non-contact ignition device for an internal combustion engine according to the present invention. FIG. 2 is a waveform diagram showing waveforms of electrical signals at various parts of the electrical circuit of the apparatus of the present invention shown in FIG. [Explanation of symbols] 1...Ignition capacitor charging coil, 3...
... Ignition capacitor, 60 ... Ignition circuit, 4 ... Timing sensor, 5 ... Ignition timing control circuit, 50 ... Short circuit current interruption control circuit, 70 ...・Timer circuit, 40... DC power supply voltage generation circuit, ■8... AC voltage generated by charging coil 1, ■ ・
...Charging voltage of ignition capacitor 3, VS...Crank position detection signal, io...Short circuit current of charging coil 1, ■b...Short circuit current cutoff signal, Vo...Short circuit current cutoff control circuit VCc: Stabilized DC power supply voltage.

Claims (1)

[Scope of Claims] The ignition capacitor is configured to be charged using a transient voltage generated when a short-circuit current of an ignition capacitor charging coil included in an alternator driven by an internal combustion engine is cut off. An ignition capacitor discharge type non-contact ignition device for an internal combustion engine, comprising: a charging coil for the ignition capacitor that supplies the generated voltage as a charging voltage for the ignition capacitor; An ignition circuit that generates a high voltage for ignition; a timing sensor that detects the crank position of the internal combustion engine and generates a crank position detection signal; and a timing sensor that receives the crank position detection signal and generates an ignition signal at the ignition timing of the internal combustion engine. an ignition timing control circuit that generates the generated signal and sends it to the ignition circuit as a trigger signal to cause discharge of the ignition capacitor; and a short-circuit current cutoff control circuit that controls cutoff of the short-circuit current of the charging coil. , to input a short circuit current cutoff signal indicating cutoff of the short circuit current sent from the short circuit current cutoff control circuit, and to return the short circuit current cutoff control circuit to the original short circuit current flowing state after a set time has elapsed; and a timer circuit for forming a return signal of and sending it to the short-circuit current interrupting control circuit, so that after the first short-circuit current is interrupted by the short-circuit current interrupting control circuit, the charging coil returns to the generated voltage. A non-contact ignition device for an internal combustion engine, characterized in that the charging coil continues to conduct and cut off a short-circuit current a plurality of times during a period in which a short-circuit current is generated.