JP3833500B2 - Ignition device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an ignition device, and more particularly, to an improvement of a high voltage output type ignition device having a small stored energy and a fast ignition cycle.
[0002]
[Prior art]
An example of a conventional ignition device will be described with reference to FIG. Reference numeral 1 denotes a blocking oscillator, 2 denotes an output transformer in which a blocking oscillator output is given to the primary winding 2a, and 3 denotes a diode that rectifies an AC voltage (for example, 800 V) induced in the secondary winding 2b of the output transformer 2.
[0003]
4 is a main capacitor charged with a rectified output, and Vc is an output voltage between its terminals. The output of the main capacitor 4 is connected to a series circuit of the primary winding 5 a of the step-up transformer 5, the auxiliary capacitor 6 and the thyristor 7.
Further, the output of the main capacitor 4 is connected to a series circuit of a secondary winding 5b of the step-up transformer 5 and a thyristor 7 of a spark plug 8.
[0004]
A dotted line block 9 is a trigger control circuit of the thyristor 7. In this circuit, the divided voltage Vi of the output voltage Vc of the main capacitor and the constant voltage Vs by the Zener diode 10 are compared by the comparator 11. When the main capacitor 4 is charged, Vc rises, and when Vi exceeds Vs, the trigger current Ig is supplied to the gate of the thyristor, and the thyristor 7 is controlled to conduct.
[0005]
Due to the conduction of the thyristor 7, a part of the charge of the main capacitor 4 charges the auxiliary capacitor 6 via the primary winding 5 a of the step-up transformer 5. The auxiliary capacitor has a capacity of about 1/10 of the main capacitor, the charging current is very small, and the charging time is short.
[0006]
A high voltage (for example, 20 KV) Vp is induced in the secondary winding 5b of the step-up transformer 5 by the current flowing in the primary winding 5a in a short time, and the charge of the main capacitor 4 is passed through the spark plug 8 sparked by this high voltage pulse. Discharges in a short time.
Furthermore, the electric charge of the auxiliary capacitor 6 is also discharged through the parallel resistor, the circuit returns to the initial state, and thereafter the same operation is periodically repeated.
[0007]
In a general ignition device design, the stored energy of the main capacitor is about 1 to 5 joules. When the main capacitor 4 is 1 μF and the auxiliary capacitor 6 is 0. 3 to 0.1 μF, it is about 5 times / sec. Sparks occur at intervals.
[0008]
[Problems to be solved by the invention]
When the use of the ignition device is expanded and a design of a high-speed (100 times / sec or more) ignition cycle with a small stored energy (for example, 20 to 30 millijoules) is assumed, in the conventional configuration of FIG. It is necessary to select 1 μF and about 0.01 μF as the auxiliary capacitor 6.
[0009]
Thus, since the capacity of the auxiliary capacitor 6 is small, when the design of the step-up transformer 5 is made the same as the conventional one, the charging current flowing in the primary winding 5a in a short time becomes extremely small, and the secondary of the step-up transformer 5 It is difficult to induce a sufficiently high voltage (for example, 20 KV) Vp in the winding 5b, and there is a problem that misfire occurs.
[0010]
An object of the present invention is to realize an ignition device that has a small stored energy and that does not cause a misfire even when designed with a high-speed cycle and a high-voltage output.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, characteristic of the first invention, one end is connected to a first capacitor means connected to one end of the rectified output of the AC voltage, to one end of the rectified output of one end the AC voltage the Second capacitor means that is charged independently of the first capacitor means, one end of the primary winding is connected to one end of the second capacitor means, and one end of the secondary winding is one end of the first capacitor means The step-up transformer means connected to the other end of the primary winding, the anode terminal being connected to the other end of the rectified output of the AC voltage, the other end of the first capacitor means, and the second capacitor means A thyristor means connected to the end, and an ignition plug having one end connected to the other end of the secondary winding and the other end connected to the anode terminal and the other end of the primary winding. , In the point.
[0012]
A feature of the second invention resides in that the first capacitor means and the second capacitor means are separated from each other by a resistance means.
[0013]
A feature of the third invention resides in that the first capacitor means and the second capacitor means are separated from each other independently by a diode means.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a circuit configuration diagram showing an embodiment of an ignition device to which the present invention is applied. The same elements as those described in FIG.
[0015]
Reference numeral 11 denotes first capacitor means, which is charged with a rectified output through a resistor constituting the separating means 13. A second capacitor means 12 is directly charged by a rectified output. Accordingly, the first and second capacitor means are charged with the rectified output independently of each other by the interposition of the separating means 13.
[0016]
The output of the first capacitor means 11 is connected to a series circuit of the secondary winding 5 b of the step-up transformer 5, the spark plug 8 and the thyristor 7. Further, the output of the second capacitor means 12 is connected to a series circuit of the primary winding 5 a of the step-up transformer 5 and the thyristor 7.
[0017]
The capacities of the first capacitor means 11 and the second capacitor means 12 are selected to be, for example, 0.1 μF, which is substantially the same as that of the auxiliary capacitor 6 of FIG. 4 and is independently about 800 V (Vc) via the rectifier diode 3. Charged.
[0018]
The operation of the trigger control circuit 9 is the same as that in FIG. 4, and the divided voltage Vi of the output voltage Vc of the second capacitor means 12 and the constant voltage Vs by the Zener diode 10 are compared by the comparator 11. When the main capacitor 4 is charged, Vc rises, and when Vi exceeds Vs, the trigger current Ig is supplied to the gate of the thyristor, and the thyristor 7 is controlled to conduct.
[0019]
Due to the conduction of the thyristor 7, the electric charge of the second capacitor means 12 is discharged through the primary winding 5 a of the step-up transformer 5. A high voltage (for example, 20 KV) Vp is induced in the secondary winding 5b of the step-up transformer 5 by the current flowing in the primary winding 5a in a short time, and the first capacitor means 11 is connected via the spark plug 8 sparked by this high voltage pulse. The electric charge is discharged in a short time, the circuit returns to the initial state, and the same operation is repeated periodically thereafter.
[0020]
FIG. 2 is a circuit configuration diagram showing another embodiment of the present invention. The difference from FIG. 1 is that a diode is used as the separating means 13, and the other configuration and operation are the same as those in FIG. is there.
[0021]
FIG. 3 is a circuit diagram showing still another embodiment of the present invention. The first capacitor means 11 is connected in series with the secondary winding 5b of the step-up transformer, and the second capacitor means 12 is the primary winding of the step-up transformer. It is characterized in that it is connected in series with the line 5a, but the operation is the same as in FIG.
[0022]
According to the present invention, a boosting discharge current is supplied to the primary winding 5a of the step-up transformer independently of the first capacitor means for supplying electric charge to the spark plug 8 via the secondary winding 5b of the step-up transformer. The capacity of the second capacitor means can be set.
[0023]
Therefore, even when the step-up transformer 5 is designed in the same manner as in FIG. 4, the primary winding current substantially equal to that in the conventional example can be supplied, so that a high voltage Vp that can sufficiently spark the ignition plug 8 is induced on the secondary winding side. It is possible to squeeze.
[0024]
Furthermore, according to the present invention, the first capacitor means 11 for supplying electric charge to the spark plug 8 through the secondary winding 5b of the step-up transformer is not affected by the trigger control circuit 9 and the second capacitor means 12, and can be freely set. Since stored energy can be selected, it becomes easy to design a high voltage output type ignition device with small stored energy.
[0025]
In the above embodiment, one end of the spark plug is connected to the secondary winding 5b of the step-up transformer and the other end is connected to the anode of the thyristor, but the other end may be connected to one end of the rectified output. Further, although the example in which the separating means 13 is inserted on the first capacitor means 11 side is shown, the effect is not changed even if it is inserted on the second capacitor means side.
[0026]
【The invention's effect】
As described above, according to the present invention, it is possible to easily realize an ignition device that has a small stored energy and does not cause a misfire even when designed with a high-speed cycle.
[Brief description of the drawings]
FIG. 1 is a circuit configuration diagram showing an embodiment of an ignition device to which the present invention is applied.
FIG. 2 is a circuit configuration diagram showing another embodiment of an ignition device to which the present invention is applied.
FIG. 3 is a circuit configuration diagram showing still another embodiment of an ignition device to which the present invention is applied.
FIG. 4 is a circuit configuration diagram showing an example of a conventional ignition device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Blocking oscillator 2 Output transformer 3 Rectifier diode 5 Boost transformer 7 Thyristor 8 Spark plug 9 Trigger control circuit 11 1st capacitor means 12 2nd capacitor means 13 Separation means

Claims (3)

A first capacitor means having one end connected to one end of the rectified output of the AC voltage,
A second capacitor means is charged independently of the one end connected to one end of the rectified output of the alternating voltage the first capacitive means,
A step-up transformer means having one end of a primary winding connected to one end of the second capacitor means and one end of a secondary winding connected to one end of the first capacitor means ;
Thyristor means having an anode terminal connected to the other end of the primary winding and a cathode terminal connected to the other end of the rectified output of the AC voltage, the other end of the first capacitor means, and the other end of the second capacitor means ;
One end is connected to the other end of the secondary winding and the other end formed by and a spark plug connected to the other end of the anode terminal and the primary winding igniter.   The ignition device according to claim 1, wherein the first capacitor means and the second capacitor means are separated from each other by a resistance means.   2. The ignition device according to claim 1, wherein the first capacitor means and the second capacitor means are separated from each other by a diode means.

Images