JPS614865A - Contactless ignitor for internal-combustion engine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

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 an internal combustion engine that is capable of advance control of the ignition timing of the internal combustion engine.

[Conventional technology]

Conventionally, in internal combustion engines such as small general-purpose engines, it has been used at the time of starting and idling to facilitate starting, stabilize during idling, reduce vibration, ensure output during normal rotation, and stabilize rotation. It is desirable to ignite near top dead center, and during acceleration and normal rotation, ignite at about several 10 degrees before top dead center.

Conventionally, for this purpose, a non-contact ignition device has been provided that detects the rotation speed of the internal combustion engine by sensing the voltage level of the power generation waveform of a power generation coil and a trigger coil generated by the rotation of a rotor having magnetic poles, and controls the ignition timing. However, due to the large influence of variations in the detected rotation speed caused by variations in the characteristics of the generator coil, trigger coil, and other electrical circuit components, when the detected rotation speed becomes low, it is difficult to achieve the desired speed during deceleration, especially when idling. If the ignition timing is not retarded and the idle speed increases, or if the detected rotation speed is particularly high, the ignition timing is not advanced to the desired ignition timing at the desired rotation speed during acceleration, resulting in deterioration of acceleration characteristics. There was a problem that this occurred.

Therefore, the present applicant has proposed a non-contact ignition device for an internal combustion engine (Japanese Patent Application No. 58-227902) that controls the ignition timing by switching the electric circuit using a switch that conducts and de-conducts in conjunction with the throttle of the internal combustion engine. provided.

[Problem that the invention seeks to solve]

In the conventional non-contact ignition system for an internal combustion engine, the ignition timing is controlled only by the throttle opening, so the ignition timing characteristics are as shown in FIG. 4. In other words, when the throttle opening is large, the ignition timing is as shown in Figure 4.
When the throttle opening is small, it becomes θ/ as shown in Figure 4 ■, and at any rotation speed of the internal combustion engine, the point at which the switch linked to the throttle opening changes. The ignition timing was advanced or retarded. For this reason, when the engine is started with the throttle wide open, the switch interlocked with the throttle has already been switched and the ignition timing is θλ, resulting in a problem of poor startability.

Furthermore, if the throttle is suddenly closed during high-speed rotation, the ignition timing will be delayed to θl during high-speed rotation, which causes a problem of backfire when used in a high-speed engine.

[Means to solve the problem]

In order to solve the above problems, the present invention provides a rotor having magnetic poles, a core placed opposite to the rotor and wound with an exciter coil and a trigger coil, and a positive induced voltage of the exciter coil charged. In a non-contact ignition device for an internal combustion engine, the non-contact ignition device for an internal combustion engine has a charging/discharging capacitor for ignition, and a first switching element that supplies the charge of the charging/discharging capacitor for ignition to an ignition coil, in which breakover occurs due to a positive induced voltage of the trigger coil. , the third switching element and the fourth switching element each having a different breakover voltage, and the switching element of the nuclear element 3 and the fourth switching element are switched, and become conductive and non-conductive in conjunction with the throttle operation of the internal combustion engine. a switch, a second switching element that is triggered by the breakover of the third switching element or the fourth switching element, and a negative induced voltage of the trigger coil to control the trigger of the switching element il; and the trigger. The configuration is characterized in that it includes a control charging/discharging capacitor that charges the positive induced voltage of the coil and controls discharging of the trigger of the first switching element.

[Effect]

According to the present invention having the above configuration, the ignition timing of the internal combustion engine is always late when the internal combustion engine rotates at low speeds such as during startup, and the ignition timing is always early when the engine rotates at high speeds.

When the throttle opening is increased such as when accelerating, the ignition timing will be advanced at a relatively low speed setting, and when the throttle opening is small such as during deceleration, the ignition timing will reach a relatively high speed setting. Ignition timing retards when rpm drops.

〔Example〕

FIG. 1 specifically shows a non-contact ignition circuit according to an embodiment of the present invention.

Reference numeral 18 denotes a rotor having at least two magnetic poles, each pole piece end having an N pole and an S pole arranged as shown in the figure, and rotates in synchronization with the internal combustion engine.

■ is an exciter coil, and 8 is a trigger filter, which are independently wound around the two legs of the U-shaped core.
is provided at a position further advanced than the trigger coil 8.

2 is a positive diode, and 3 is an ignition charging/discharging capacitor, which are connected in series to the primary coil 4a of the ignition coil 4. A thyristor 5, which is a switching element, and a forward diode 7 are connected in series, and these constitute a discharge circuit that supplies the charge of the capacitor 3 to the secondary coil 4α.

Note that a spark plug 17 is connected to the secondary coil 4hK of the ignition coil 4.

Further, a diode 10 and a control charging/discharging capacitor 13 are connected in series to the trigger coil 8, and one end of the trigger coil 8 is grounded together with one end of the exciter coil 1 and one end of the primary coil 4a and secondary coil 4h of the ignition coil 4. ing.

Further, the anode of a thyristor 11, which is a switching element of the fan 2, is connected to the midpoint of the connection between the diode 10 and the capacitor 13, and the cathode of the thyristor 11 is connected to the gate of the thyristor 5, and the gate of the thyristor 11 is connected in the opposite direction. It is grounded via a diode 15. Then, between the anode and gate of the thyristor 11, a fourth
a Zener diode 12 which is a switching element, and a switch that is linked to the throttle of the internal combustion engine and becomes non-conductive when the throttle opening is small and becomes conductive when the throttle opening is large]6
and a Zener diode 14, which is a third switching element, are connected in parallel as shown in the figure. Further, a reverse diode 9 is connected between the cathode of the thyristor 11 and the anode of the diode 10. Note that the Zener voltage of the thyristor 12 is set lower than the Zener voltage of the thyristor 14.

Note that 6 is a reverse diode connected between the capacitor 3 and the ground terminal of the primary coil 4a of the ignition coil 4.

In the present invention having the above structure, when the rotor 18 rotates, voltages shown in FIGS. 2(a) and 2(h) are induced in the exciter coil 1 and the trigger coil 8, respectively.

First, the path of the primary coil 4a of the diode 2 - capacitor 3 - ignition coil 4 is such that a voltage waveform in the positive direction ■ is induced in the exciter coil 1 regardless of the rotational speed of the internal combustion engine and the conduction or non-conduction of the switch 16. Current flows and charges the capacitor 3VC.

Next, we will explain the circuit operation when the throttle opening of the internal combustion engine is small, that is, when the switch 16 is in a non-conducting state, by dividing it into low-speed rotation such as when starting the internal combustion engine, and high-speed rotation. do.

First, during low-speed rotation such as during startup, when a voltage waveform in the positive direction ■ is induced in the trigger coil 8, the diode 10→
A current flows through the path of the capacitor 13, charging the capacitor 13 with electricity. At this time, the induced voltage does not reach the Zener voltage of the Zener diode 14, so the Zener diode 14 does not break over and the thyristor 11 and the thyristor 5 are not tripped. Next, when a voltage waveform in the negative direction ■ is induced in the tri-force coil 8, the diode 15→
A current flows through the path from the gate and cathode of the thyristor 11 to the diode 9 and triggers the thyristor 11, so that the charge in the capacitor 13 flows through the path from the anode and cathode of the thyristor 11 to the gate and cathode of the thyristor 5 and the diode 7. The voltage is discharged and the thyristor 5 is tripped. As a result, the charge in the capacitor 3 is transferred to the thyristor 5.
Discharge occurs in the path of the anode/cathode → diode 7 → primary coil 4a of the ignition coil 4, and the secondary coil 4
A high voltage is induced in b to generate a spark in the spark plug 17. That is, the ignition timing is θ/.

The waveform of the charging voltage C3 of the capacitor 3 at this time is shown by the solid line in Figure 2 (C). In addition, the trigger coil 8'
When a voltage waveform in the negative direction ■ is induced, the thyristor 11 is triggered in the same way as when the voltage waveform in the negative direction ■ is triggered.
At this point, the thyristor 5 is not triggered because the charge in the capacitor 13 has already been discharged.

During medium and high speed rotation, when a voltage in the positive direction (2) is induced in the trigger coil 8, the Zener diode 14 breaks over, and the diode 10-4 Zener diode 14 → the gate and cathode of the thyristor 11 - the gate and cathode of the thyristor 5. A current flows through the path between the cathode and the diode 7, and the charge in the capacitor 13 also flows through the thyristor 1.
The discharge occurs along the path from the anode and cathode of thyristor 1 to the gate and cathode of thyristor 5 to diode 7, and triggers thyristor 11 and thyristor 5. Therefore, the ignition timing is θ, and the ignition timing is advanced by Δθ with respect to θ/.

The waveform of the charging voltage vc3 of the capacitor 3 at this time is
It is shown in the dashed line in Figure (C). Note that when a voltage waveform in the negative direction (1) or (2) is induced in the trigger coil 8, the circuit operates in the same way as when the voltage waveform in the negative direction (2) occurs during low-speed rotation such as at the time of starting. That is, the thyristor 5 is not triggered when the voltage waveform is in the negative direction (2), and the thyristor 5 is also not triggered when the voltage waveform is in the negative direction (2). this is,
This is because although the thyristor 11 can be triggered, the capacitor 13 has no charge.

Therefore, when the opening degree of the throttle of the internal combustion engine is small, the ignition timing characteristic becomes as shown by the dashed line in FIG. The ignition timing is switched at a set rotational speed N, 2, which is relatively high speed side.

Second, regarding the circuit operation when the throttle opening of the internal combustion engine is large, that is, when the switch 16 is in a conductive state, the Zener voltage of the Zener diode ll'l is smaller than the Zener voltage of the Zener diode 14, so the above In the description of the circuit operation in the first case, the Zener diode 14 may be replaced with the Zener diode 12, so the explanation will be omitted.

Therefore, when the throttle opening of the internal combustion engine is wide, the ignition timing characteristic becomes as shown by the solid line in Figure 3, and ignition occurs at the rotation speed Nt that is lower by ΔN than the rotation speed NJK, that is, the set rotation speed N/ which is relatively low speed. The time period changes.

From the above, the ignition timing of the internal combustion engine is always as slow as θl during low speed rotation such as during startup, and the ignition timing is always θλ earlier by Δθ than θ/ during medium and high speed rotation. When the throttle opening is increased such as when accelerating, the ignition timing becomes as early as θ with the set rotation speed Nl on the relatively low speed side, and when the throttle opening is small such as during deceleration, the ignition timing becomes as early as θ. When the rotation speed drops to the set rotation speed Nu, the ignition timing is delayed to θl.

Note that the set rotation speed Nt on the relatively low speed side can be determined by considering only startability and acceleration characteristics, and the set rotation speed N- on the relatively high speed side can be determined only by considering the rotation speed during deceleration and when backfire occurs. Therefore, the above-mentioned set rotation speed Ni caused by variations in the characteristics of the Zener diode 12゜14, the generator coil, other electric circuit parts, etc.
.

〔Effect of the invention〕

The present invention provides a rotor having magnetic poles, a core disposed opposite to the rotor and having an exciter coil and a tri-coil wound therein, and an ignition charge/discharge capacitor that charges the positive induced voltage of the exciter coil. A non-contact ignition device for an internal combustion engine having a first switching element that supplies the charge of the ignition charge/discharge capacitor to the ignition coil, wherein breakover occurs due to a positive induced voltage of the trigger coil, and the breakover voltages are different. a third switching element, a fourth switching element, a switch that switches between the switching element of the nuclear element 3 and the fourth switching element, which becomes conductive and non-conductive in conjunction with throttle operation of the internal combustion engine; and a third switching element. the switching element of fang 2 which controls the triggering of the first switching element by being triggered by the breakover of the element or the fourth switching element and by the negative induced voltage of said trigger coil 0, and the positive induced voltage of said trigger coil. By adopting a configuration characterized by comprising a control charging/discharging capacitor that charges the internal combustion engine and controls discharging of the trigger of the first switching element, the startability of the internal combustion engine deteriorates even when the throttle of the internal combustion engine is wide open. This makes it easier to start, stabilizes during idle rotation, reduces vibration, secures and stabilizes output during normal rotation, improves acceleration characteristics, and prevents backfire from occurring even when used in high-speed engines. Furthermore, it has the advantage of being small, lightweight, and inexpensive.

[Brief explanation of drawings]

Figure 1 is a specific circuit diagram of the non-contact ignition device of the present invention.
The figure is a voltage waveform diagram of each part of the circuit, Figure 3 is an ignition timing characteristic diagram,
FIG. 4 is an ignition timing characteristic diagram of a conventional non-contact ignition device. DESCRIPTION OF SYMBOLS 1... Exciter coil, 3... Charge/discharge capacitor for ignition, 4-... Ignition coil, 5... First switching element, 8... Tri-force coil, 11...
Switching element of tooth 2, 12... Fourth switching element, 13... Control charge/discharge capacitor, 14...
@Third switching element, 16... switch, 18
...Rotor.

Claims (1)

[Claims] A rotor having magnetic poles, a core disposed opposite to the rotor and having an exciter coil and a trigger coil wound thereon, an ignition charging/discharging capacitor for charging the positive induced voltage of the exciter coil, and the ignition charging/discharging capacitor. A non-contact ignition device for an internal combustion engine having a first switching element that supplies the charge of the capacitor to the ignition coil,
A third switching element and a fourth switching element that break over due to the positive induced voltage of the trigger coil and have different breakover voltages, and switching between the third switching element and the fourth switching element; A switch that becomes conductive or non-conductive in conjunction with throttle operation of the internal combustion engine, and a third switching element or a fourth switching element.
A second switching element that is triggered by the breakover of the switching element and the negative induced voltage of the trigger coil to control the trigger of the first switching element, and a positive induced voltage of the trigger coil,
A non-contact ignition device for an internal combustion engine, comprising a control charge/discharge capacitor that controls discharge of a trigger of a first switching element.