JPH0565862A - Ignition device for internal combustion engine - Google Patents

Abstract

(57) [Abstract] [Object] To provide an ignition device for an internal combustion engine, which has a large capacity energy for ignition and a large inductive energy and is capable of stably igniting a lean fuel having a large air-fuel ratio. To aim. [Configuration] A primary coil 4 for discharge ignition in which a capacitor discharge type ignition device and a transistor cut-off type ignition device are combined, and a primary coil 4 for discharge ignition in which a charged charge of a capacitor 8 is discharged and a primary coil for control ignition in which a current is cut off by a transistor 6 3 and 3 are wound around a common core 1, and a secondary coil 5 is provided in common to these cores, and a spark is generated in the ignition plug 23 by the high voltage generated by the secondary coil 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for an internal combustion engine, and in particular, a high voltage is induced in the secondary coil of the ignition coil by changing the current of the primary coil of the ignition coil. The present invention relates to an ignition device that ignites by generating a spark.

[0002]

2. Description of the Related Art Ignition devices used in small engines without a battery include a capacitor discharge type ignition device and a transistor control type ignition device.

The capacitor discharge type ignition device charges the discharge capacitor by the output of the exciter coil and makes the thyristor conductive at a predetermined timing, and the charge of the discharge capacitor is rapidly passed through the thyristor to the primary coil of the ignition coil. The secondary coil is supplied with a high voltage to generate a spark in the plug.

On the other hand, in the transistor-controlled ignition device, the primary coil of the ignition device is also used as the generator coil, and the collector and the emitter of the transistor are connected to both ends of the primary coil. At this timing, the transistor is cut off to suddenly cut off the current flowing in the primary coil of the ignition coil, and the change in the magnetic flux at this time is used to induce a high voltage in the secondary coil to generate a spark in the ignition plug. It is the one.

[0005]

The spark generated by the spark plug is composed of a capacity spark (capacity energy) that forms a flame kernel of combustion and an induction spark (induction energy) that assists combustion. The capacitor discharge type ignition device used conventionally has a characteristic that the capacity energy is large, but the induction energy is small. On the contrary, the transistor-controlled ignition device has a property that the capacity energy is small and the inductive energy is large.

In order to easily start the engine and maintain comfortable driving, it is necessary that both the capacity energy and the induced energy are large. However, each of the above-mentioned two types of ignition devices has advantages and disadvantages, and is currently used properly according to the purpose and application.

On the other hand, in order to improve the exhaust gas of a gasoline engine, there is a tendency to increase the air-fuel ratio of the engine and employ lean combustion. When the lean fuel having a large air-fuel ratio is supplied to the engine, the ignitability of the engine deteriorates. Therefore, it is necessary to increase the energy of the ignition spark. In this case, it is necessary to increase both capacitive energy and inductive energy. However, as described above, the two types of conventional ignition devices have different types of small energy. In addition, there is a defect in the energy discharge pattern, and there is a problem in the distribution of capacitive energy and inductive energy.

The present invention has been made in view of the above problems, and provides an ignition device for an internal combustion engine capable of reliably performing ignition for performing lean combustion with a particularly large air-fuel ratio. The purpose is.

[0009]

According to a first aspect of the present invention, there is provided a capacitor discharge type ignition circuit and a current interruption control type ignition circuit, wherein the capacitor discharge type ignition circuit includes an exciter coil for generating a power output. A discharge capacitor charged by the power generation coil and a discharge ignition primary coil to which the charge of the discharge capacitor is supplied are provided. On the other hand, the current interruption control type ignition circuit is a control for generating a power generation output An ignition primary coil and a switching element for controlling interruption of a current flowing through the control ignition primary coil are provided.
The discharge ignition primary coil and the control ignition primary coil are magnetically coupled to a common secondary coil, and an ignition plug is connected to the common secondary coil.

According to a second aspect of the present invention, a semiconductor switching element is connected between the discharge capacitor and the discharge ignition primary coil, and the semiconductor switching element is connected to a control electrode of the switching element. When the switching element is closed, the switching element is cut off. ..

In a third aspect of the invention, the primary coil for controlled ignition is connected to the control electrode of the semiconductor switching device, and
A timing adjustment capacitor is connected to the control electrode, and the exciter coil is connected to the control electrode of the semiconductor switching element. When the rotation speed is low, the timing adjustment is performed by the output of the control ignition primary coil. The semiconductor switching element is closed via a capacitor for use, and the semiconductor switching element is closed by the output of the exciter coil when the rotation speed increases.

A fourth invention is the exciter coil,
The discharge ignition primary coil, the control ignition primary coil, and the secondary coil are wound around a common core and fixedly arranged on the outer peripheral portion of a rotor including a magnet.

[0013]

According to the first aspect of the present invention, a voltage corresponding to a change in the currents of the discharge ignition primary coil and the control ignition primary coil is generated in the common secondary coil. Sparks fly to the spark plug by the energy obtained by superimposing the ignition energy of the above and the ignition energy of the current interruption control type ignition device.

According to the second aspect of the invention, the semiconductor switching element is closed at a predetermined timing, and the output of the discharge capacitor is rapidly supplied to the discharge ignition primary coil. Moreover, the switching element is cut off in synchronization with the closing of the semiconductor switching element, and the current in the primary coil for controlled ignition is cut off rapidly. Therefore, the changes in the currents flowing through the two primary coils occur in a state of being substantially synchronized with each other.

According to the third aspect of the invention, when the rotational speed is low, the timing adjusting capacitor is first charged by the output of the control ignition primary coil, and the charging voltage of this capacitor exceeds a predetermined value. At this stage, the semiconductor switching element is closed, and the ignition operation is performed at this time. When the rotation speed increases, the semiconductor switching device is closed by the output of the exciter coil, and the timing is advanced by the charging time of the timing adjustment capacitor.

According to the fourth invention, the exciter coil, the discharge ignition primary coil, the control ignition primary coil, and the common secondary coil are wound together on the common core. As a result, an ignition device that superimposes two types of ignition energy to perform an ignition operation is incorporated on a common core.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a circuit configuration of an ignition device according to an embodiment of the present invention. Further, FIG. 2 shows the configuration of the coil wound around the core 1. An exciter coil 2, a control ignition primary coil 3, a discharge ignition primary coil 4, and a common secondary coil 5 are wound around the core 1. The four types of coils 2 to 5 are connected as shown in FIG.

Both ends of the controlled ignition primary coil 3 are connected to the collector and the emitter of the transistor 6, respectively. A diode 16 is connected between the coil 3 and the collector of the transistor 6. On the other hand, the exciter coil 2 is connected to the discharging capacitor 8 via the diode 10. Then, in order to discharge the electric charge of the discharging capacitor 8 to the primary coil 4, the thyristor 7
Is provided. The gate of this thyristor 7 has a resistor 1
It is connected to the plus side terminal of the controlled ignition primary coil 3 via a series circuit of 9, 17 and a diode 16. Further, a series circuit of a capacitor 9 and resistors 18 and 19 is connected to the gate of the thyristor 7, and the gate of the thyristor 7 is connected to the negative terminal of the control ignition primary coil 3 via this series circuit. It has become so.

Further, this circuit is further provided with Dade 11-15.
And are connected as shown in FIG. Further, this circuit includes resistors 20 to 22, which are respectively connected to predetermined positions as shown in FIG. A spark plug 23 is connected to the secondary coil 5 of the ignition coil.

The exciter coil 2, the control ignition primary coil 3, the discharge ignition primary coil 4 and the secondary coil 5 are wound around a bobbin 25 as shown in FIG. The bobbin 25 is inserted and attached to one leg of the core 1. The core 1 is fixedly arranged so as to face the outer peripheral surface of the rotor 26. The rotor 25 is the magnet 2
7, and pole pieces 28 are provided at the magnetic pole portions at both ends of the magnet 27, and these pole pieces 28 face the outer peripheral surface of the rotor 26.

In the above structure, when the rotor 26 rotates, the magnetic flux passes through the core 1 by the magnet 27 and the pole piece 28 provided on the rotor 26. The change in the magnetic flux at this time causes the exciter coil 2 and the control ignition primary coil 3 to generate power generation outputs as shown in FIG. 3, respectively. That is, the two types of coils 2 and 3 generate outputs of opposite polarities substantially in synchronization with each other.

The output B of the second wave on the positive side of the exciter coil 2 causes a current to flow in the order of the exciter coil 2, the diode 10, the capacitor 8, the diode 11, and the exciter coil 2 to charge the capacitor 8. At this time, the power generation output generated in the control ignition primary coil 3 and the discharge ignition primary coil 4 is blocked by the diode 16 and the charged capacitor 8, respectively.

Due to the rotation of the rotor 26, the output generated in the exciter coil 2 and the primary ignition coil 3 for control ignition changes to the output C on the negative side and the positive side in FIG. When the engine speed is low, the output of the exciter coil 2 is the exciter coil 2, the resistor 21, the gate of the thyristor 7,
The cathode, the diode 12, and the exciter coil 2 flow in this order. Further, a part of the current does not pass through the gate and the cathode of the thyristor 7 but returns to the exciter coil 2 through the resistor 20. Since the current value at this time is small, the thyristor 7 does not conduct.

At this time, the positive side output C is generated in the controlled ignition primary coil 3, so that a current flows in the order of the primary coil 3, the diode 16, the collector of the transistor 6, the emitter thereof, and the primary coil 3. .. Further, part of the current flowing through the diode 16 is the resistance 22, the diodes 14, 15,
The current is shunted to the base and the emitter of the transistor 6. In addition, part of the current flowing through the diode 16 is the resistance 17, 19,
The gate and the cathode of the thyristor 7 flow in this order and return to the primary coil 3.

Then, a part of the current is shunted to the series circuit of the resistor 18 and the capacitor 9 which are parallel to the resistor 19 and returns to the primary coil 3. That is, when the control ignition primary coil 3 produces a plus side output C, the timing adjustment capacitor 9 is charged thereby.

When the charging of the capacitor 9 is completed, the resistor 1
The current flowing in the series circuit of 8 and capacitor 9 decreases,
This increases the current flowing into the gate of the thyristor 7 through the resistor 19. Therefore, in FIG. 3, the thyristor 7 becomes conductive at the timing of t ₁ .

When the thyristor 7 becomes conductive, the electric charge charged in the discharging capacitor 8 flows in the order of the capacitor 8, the anode and cathode of the thyristor 7, the discharge ignition primary coil 4 and the discharging capacitor 8. The capacitor 8 is discharged. Then, a high voltage is induced in the secondary coil 5 by the change in the current flowing through the discharge ignition primary coil 4, and the spark plug 23 generates a spark as shown in FIG.

When the thyristor 7 becomes conductive, the transistor 6 whose base is connected to the anode of the thyristor 7 via the diodes 13, 14 and 15 is cut off. Therefore, the current that has been flowing through the control ignition primary coil 3 is suddenly cut off, so that a high voltage is induced in the secondary coil 5 and a spark is generated in the ignition plug 23 as shown in FIG. .. That is, the secondary coil 5 changes the current of the discharge ignition primary coil 4 and controls ignition primary coil 3
The change in the electric current of (1) induces a high voltage corresponding to the superposed amount, which causes the spark plug 23 to generate a spark as shown in FIG.

As the engine speed increases, FIG.
The output waveform shown in is also increased. Therefore, unlike the above-described low speed operation, the output of the exciter coil 2 causes a current to flow in the order of the exciter coil 2, the resistor 21, the gate of the thyristor 7, the cathode, the diode 12, and the exciter coil 2, and the thyristor 7 becomes conductive.

With the conduction of the thyristor 7, the charge of the charging / discharging capacitor 8 is supplied to the discharge ignition primary coil 4 through the thyristor 7, and the transistor 6 is cut off with the conduction of the thyristor 7, thereby controlling the thyristor 7. For ignition 1
The current in the next coil 3 is suddenly cut off. Therefore, the energy of the primary coil 4 for discharge ignition and the primary coil 3 for control ignition are superimposed and supplied to the secondary coil 5, and a spark is generated in the ignition plug 23. The ignition timing at this time is t in FIG.
_{Is 2} . That is, as the rotation speed increases, t ₁ to t
Advances to ₂ .

The output A of the first wave on the negative side and on the positive side generated in the exciter coil 2 and the primary coil 3 for controlled ignition.
Performs the same operation as the output C of the third wave. However, at this time, since the discharge capacitor 8 is not yet charged with electric charge, the discharge ignition primary coil 4 does not generate energy, and only the control ignition primary coil 3 supplies the spark energy. Become. However, the spark voltage at this time is extremely low. That is, there is no energy in the capacitor 8 and only the energy obtained by the control ignition primary coil 3, so that the value is low. Therefore, no spark is generated in the spark plug 23. Even if a slight spark is generated in the plug 23, the engine has not yet entered the compression process at this time, and therefore ignition is not performed.

The ignition device of this embodiment is designed to generate a spark by superimposing the energy due to the electric charge that the capacitor 8 rapidly discharges and the energy due to the interruption of the transistor 6 of the control ignition primary coil 3. .. Therefore, in particular, the ignition energy generated by the discharge ignition primary coil 4 by the capacitor 8 can generate the capacity energy that constitutes the flame nucleus of combustion. Further, the combustion can be assisted by the induced energy generated by the interruption of the control ignition primary coil 3 by the transistor 6. Therefore, sparks with extremely good ignition and combustion can be generated by the plug 23.

Further, the ignition timing is shown in FIG.
It becomes possible to advance the angle as shown in. Therefore, even if a lean fuel with a large air-fuel ratio is supplied to improve exhaust gas,
Ignition delay can be covered. That is, in the case of lean fuel, since the ignition time is delayed, it is possible to advance the ignition by that amount and ignite earlier. This has the advantage that clean combustion is achieved and exhaust gas measures are easier.

[0034]

According to the first aspect of the invention, the discharge ignition primary coil and the control ignition primary coil are magnetically coupled to a common secondary coil, and an ignition plug is connected to the secondary coil. It was done like this. Therefore, the energy of the discharge ignition primary coil accompanying the discharge of the capacitor and the energy of the control ignition primary coil due to the interruption of the switching element can be superimposed to induce a high voltage in the common secondary coil. It is possible to provide an igniter having both large capacity energy and large inductive energy.

According to the second aspect of the present invention, when the semiconductor switching element is closed, the electric charge of the discharging capacitor is supplied to the primary coil for discharge ignition, and in synchronization with this, the switching element controls ignition. As a result, the primary coil for the vehicle is cut off, the two kinds of ignition operations are performed in synchronization with each other, and the two ignition operations can be correctly aligned in time.

According to the third aspect of the invention, when the engine speed is low, the ignition timing is delayed by charging the timing adjustment capacitor, and when the engine speed is increased, the output of the exciter coil directly The ignition operation is started, and the ignition timing is advanced according to the engine speed.

According to the fourth invention, the exciter coil, the discharge ignition primary coil, the control ignition primary coil and the secondary coil are wound around a common core. It is possible to compactly configure the ignition device including the types of coils.

[Brief description of drawings]

FIG. 1 is a circuit diagram of an internal combustion engine ignition device according to an embodiment.

FIG. 2 is a front view of a core around which a coil is wound.

FIG. 3 is a graph showing power generation output waveforms of an exciter coil and a controlled ignition primary coil.

FIG. 4 is a graph showing a change in energy for ignition.

FIG. 5 is a graph showing changes in ignition timing with respect to engine speed.

[Explanation of symbols]

 1 core 2 exciter coil 3 primary coil for control ignition 4 primary coil for discharge ignition 5 secondary coil 6 transistor 7 thyristor 8 discharge capacitor 9 timing adjustment capacitor 10-16 diode 17-22 resistance 23 spark plug 25 bobbin 26 Rotor 27 magnet 28 pole piece

Claims (4)

[Claims] 1. A capacitor discharge type ignition circuit and a current interruption control type ignition circuit, wherein the capacitor discharge type ignition circuit includes an exciter coil for generating a power generation output, and a discharge capacitor charged by the power generation coil. , A discharge ignition primary coil to which the electric charge of the discharge capacitor is supplied, whereas the current interruption control type ignition circuit includes a control ignition primary coil for generating a power generation output, and the control ignition. A switching element for controlling interruption of the current flowing through the primary coil for use in ignition, the primary coil for discharge ignition and the primary coil for control ignition are magnetically coupled to a common secondary coil, and the common An ignition device for an internal combustion engine, wherein an ignition plug is connected to the secondary coil. 2. A semiconductor switching element is connected between the discharge capacitor and the discharge ignition primary coil, and the semiconductor switching element is connected to a control electrode of the switching element, and the semiconductor switching element is closed. The ignition device for an internal combustion engine according to claim 1, wherein the switching element is cut off when the ignition device is formed. 3. The control ignition primary coil is connected to a control electrode of the semiconductor switching element, a timing adjusting capacitor is connected to the control electrode, and the exciter coil is connected to the control electrode of the semiconductor switching element. When the rotational speed is low, the output of the control ignition primary coil closes the semiconductor switching element via the timing adjusting capacitor, and when the rotational speed increases, the output of the exciter coil 3. The ignition device for an internal combustion engine according to claim 2, wherein the semiconductor switching element is closed by means of. 4. The exciter coil, the discharge ignition primary coil, the control ignition primary coil, and the secondary ignition coil.
The ignition device for an internal combustion engine according to claim 1, wherein the secondary coil is wound around a common core and is fixedly arranged on an outer peripheral portion of a rotor including a magnet.