JPS6347908B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a non-contact ignition device for an internal combustion engine.
In particular, the present invention relates to a non-contact ignition device for a internal combustion engine that can advance the ignition timing of an internal combustion engine.

[Conventional technology]

Conventionally, internal combustion engines such as small general-purpose engines have been used to facilitate starting, stabilize idle rotation,
In order to reduce vibration, secure output during normal rotation, and stabilize rotation, the ignition is ignited near top dead center when starting the internal combustion engine and during idle rotation, and ignited around several 10 degrees before top dead center during acceleration and normal rotation. It is desired that the light be ignited.

Conventionally, for this purpose, non-contact ignition devices have been developed that control the ignition timing by detecting 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. However, the influence of variations in the detected rotation speed caused by variations in the characteristics of the generator coil, trigger coil, other electric circuit components, etc. is large, so when the detected rotation speed becomes low, the speed decreases during deceleration, especially when idling. If the ignition timing does not retard to the desired ignition timing during rotation and the idling speed increases, or if the detected rotation speed is particularly high, the ignition timing does not advance to the desired ignition timing at the desired rotation speed during acceleration, resulting in poor acceleration characteristics. There was a problem that there were cases where the condition worsened.

Therefore, the present applicant developed a non-contact ignition system 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. ) are 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. That is, when the throttle opening is large, the ignition timing becomes Θ ₂ as shown in Fig. 4, 7.
When the throttle opening is small, the ignition timing becomes Θ ₁ as shown in Fig. 4, and at any rotational speed of the internal combustion engine, the ignition timing is advanced or It was late. For this reason, when starting the engine with the throttle wide open, the switch linked to the throttle has already been switched and the ignition timing is _Θ2 , which poses a problem in that starting performance deteriorates.

In addition, if the throttle is suddenly closed during high-speed rotation, the ignition timing will be delayed to Θ ₁ at high-speed rotation, which causes 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 an ignition charge/discharge capacitor, and a first switching element that supplies the charge of the ignition charge/discharge capacitor to an ignition coil. The third switching element and the fourth switching element have different breakover voltages, and the third switching element and the fourth switching element are switched to conduction and conduction in conjunction with the throttle operation of the internal combustion engine. a second switching device which controls the triggering of the first switching device triggered by the breakover of the switch becoming non-conductive and the third switching device or the fourth switching device and by the negative induced voltage of the trigger coil; The device is characterized in that it includes a control charging/discharging capacitor that charges the positive induced voltage of the trigger coil and controls discharging of the trigger of the first switching device.

[Operation] 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 or more 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. 1 is an exciter coil, and 8 is a trigger coil, which are each independently wound around the two leg pieces of a U-shaped core, and the exciter coil 1 is further advanced than the trigger coil 8 in the rotational direction of the rotor 18. located at the location.

2 is a positive direction diode, 3 is an ignition charging/discharging capacitor, these are connected in series to the primary coil 4a of the ignition coil 4, and a charging circuit is configured to charge the capacitor 3 with the positive voltage induced in the exciter coil 1. In addition, this capacitor 3 is connected to the primary coil 4a of the ignition coil 4.
A thyristor 5, which is a first switching element, and a forward diode 7 are connected in series through the thyristor 5, which constitutes a discharge circuit that supplies the charge of the capacitor 3 to the primary coil 4a.

In addition, the secondary coil 4b of the ignition coil 4
A spark plug 17 is connected to.

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 4b of the ignition coil 4. has been done.

Further, the anode of a thyristor 11, which is a second switching element, 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. Between the anode and gate of the thyristor 11, there is a Zener diode 12, which is a fourth switching element, and a switch 16, which works in conjunction with the throttle of the internal combustion engine and becomes non-conductive when the throttle opening is small and conductive when the throttle opening is large. and a Zener diode 14, which is a third switching element, are connected in parallel as shown in the first diagram. Also,
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, the voltages shown in FIG. 2 a and b are induced in the exciter coil 1 and the trigger coil 8, respectively.

First, when a positive voltage waveform is induced in the exciter coil 1 regardless of the rotational speed of the internal combustion engine and the conduction/nonconduction of the switch 16, the path of the primary coil 4a of the diode 2 → capacitor 3 → ignition coil 4 A current flows and charges the capacitor 3.

Next, first, we will explain the rotational 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 positive voltage waveform is induced in the trigger coil 8, a current flows through the path from the diode 10 to the capacitor 13, and charges the capacitor 13. 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 triggered. Next, when a negative voltage waveform is induced in the trigger coil 8, a current flows through the path of the diode 15 → the gate/cathode of the thyristor 11 → the diode 9, triggering the thyristor 11, and as a result, the charge in the capacitor 13 is discharged along the path of the anode/cathode of the thyristor 11 → the gate/cathode of the thyristor 5 → the diode 7, and triggers the thyristor 5. As a result, the charge in the capacitor 3 is discharged along the path of the anode/cathode of the thyristor 5 → the diode 7 → the primary coil 4a of the ignition coil 4, inducing a high voltage in the secondary coil 4b, and causing the spark plug 17
generate a spark. That is, the ignition timing is Θ ₁
becomes. The waveform of the charging voltage _Vc3 of the capacitor 3 at this time is shown by the solid line c in FIG. Note that when a negative voltage waveform is induced in the trigger coil 8, the thyristor 11 is triggered in the same manner as in the case of the negative voltage waveform, but at this point, the charge in the capacitor 13 has already been discharged. Therefore, thyristor 5 is not triggered.

During medium and high speed rotation, when a positive voltage is induced in the trigger coil 8, the Zener diode 14 breaks over and the diode 1
A current flows in the path of 0 → Zener diode 14 → gate and cathode of thyristor 11 → gate and cathode of thyristor 5 → diode 7, and the charge in the capacitor 13 also flows from the anode and cathode of thyristor 11 → the gate and cathode of thyristor 5. → Discharges through the path of diode 7, and thyristor 1
1 and thyristor 5. Therefore,
The ignition timing is Θ ₂ , which is advanced by △Θ compared to Θ ₁ . The waveform of the charging voltage _Vc3 of the capacitor 3 at this time is shown by the dashed line in FIG. 2c. In addition,
When a voltage waveform in the negative direction is induced in the trigger coil 8, the circuit operates in the same way as when the voltage waveform in the negative direction 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, and the thyristor 5 is also not triggered when the voltage waveform is in the negative direction. 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. Set engine speed at relatively high speed
Ignition timing changes with N ₂ .

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 diode 1
Since the Zener voltage of No. 2 is smaller than the Zener voltage of the Zener diode 14, the Zener diode 12 may be substituted for the Zener diode 14 in the circuit operation description for the first case, so the explanation will be omitted.

Therefore, when the throttle opening of the internal combustion engine is large, the ignition timing characteristic becomes as shown by the solid line in Figure 3, and the rotation speed is lower by △N than the above rotation speed _N2 .
The ignition timing is switched at N ₁ , that is, the set rotation speed N ₁ on the relatively low speed side.

From the above, the ignition timing of the internal combustion engine is always as slow as Θ ₁ during low speed rotation such as during startup, and the ignition timing is always Θ ₂ earlier than Θ ₁ during medium and high speed rotation. When the throttle opening is increased, such as when accelerating, the ignition timing will be as early as Θ ₂ at a relatively low speed setting of N ₁ , and when the throttle opening is small, such as during deceleration, the ignition timing will be at the relatively high speed side. When the rotation speed drops to the set rotation speed N ₂ , the ignition timing is delayed to Θ ₁ .

In addition, the set rotation speed N ₁ on the relatively low speed side is for starting performance,
It can be determined by considering only the acceleration characteristics, and the set rotation speed _N2 on the relatively high speed side can be determined by considering only the rotation speed during deceleration and backup fire generation. , when the idle speed particularly increases during deceleration or when acceleration characteristics deteriorate due to variations in the set rotation speeds N ₁ and N ₂ caused by variations in the characteristics of other electric circuit components, etc. There will be no problems, and no backfires will occur.

〔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 trigger coil wound thereon, an ignition charging capacitor for charging the positive induced voltage of the exciter coil, and an ignition charging capacitor for charging the positive induced voltage of the exciter coil. In a non-contact ignition device for an internal combustion engine, the non-contact ignition device for an internal combustion engine has a first switching element that supplies the electric charge of a charging/discharging capacitor to an ignition coil. a different third switching element and a fourth switching element; a third switching element and a fourth switching element;
The negative induced voltage of the trigger coil is caused by the breakover of the third switching element or the fourth switching element, and the negative induced voltage of the trigger coil. a second switching element that controls the trigger of the first switching element when triggered by the trigger; and a control charging/discharging capacitor that charges the positive induced voltage of the trigger coil and controls the discharge of the trigger of the first switching element. By adopting a configuration characterized by the following features, starting performance does not deteriorate even when the throttle of the internal combustion engine is wide open, making it easier to start, stabilizing during idle rotation, reducing vibration, and making it easier for regular use. It is possible to secure and stabilize output during rotation and improve acceleration characteristics, and even when used in a high-speed engine, no backfire occurs, and furthermore, it has the effect of being small, lightweight, and inexpensive.

[Brief explanation of the drawing]

Fig. 1 is a specific circuit diagram of the non-contact ignition device of the present invention, Fig. 2 is a voltage waveform diagram of each part of the circuit, Fig. 3 is an ignition timing characteristic diagram, and Fig. 4 is the ignition timing of a conventional non-contact ignition device. It is a characteristic diagram. 1... Exciter coil, 3... Ignition charging/discharging capacitor, 4... Ignition coil, 5...
first switching element, 8... trigger coil,
11... second switching element, 12... fourth
switching element, 13... control charge/discharge capacitor, 14... third switching element, 16
...Switch, 18...Rota.

Claims (1)

[Claims] 1. 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 for charging the positive induced voltage of the exciter coil. In a non-contact ignition device for an internal combustion engine, which has a first switching element that supplies the electric charge of a discharge capacitor to an ignition coil, a breakover occurs due to the positive induced voltage of the trigger coil, and a first switching element with different breakover voltages is provided. a third switching element and a fourth switching element, a switch that switches between the third switching element and the fourth switching element and becomes conductive and non-conductive in conjunction with throttle operation of the internal combustion engine; and a third switching element. The first switching element is triggered by the breakover of the switching element or the fourth switching element and by the negative induced voltage of the trigger coil.
A second switching element that controls the trigger of the switching element; and a control charging/discharging capacitor that charges the positive induced voltage of the trigger coil and controls discharging of the trigger of the first switching element. Non-contact ignition system for internal combustion engines.