JPS61294167A - Ignitor for internal-combustion engine - Google Patents

Abstract

PURPOSE:To obtain the spark energy increased by an inexpensive and small- sized apparatus by adding the primary auxiliary coil having the less number of winding than that of the primary coil and the primary auxiliary electric- current connecting and disconnecting means for cutting off the electric conduc tion to the primary auxiliary coil, onto a normal electric-current cut-off type ignitor. CONSTITUTION:A spark energy increasing circuit 200 is excited for an ordinary electric-current cut-off type ignitor 100. Said increasing circuit 200 is equipped with a variable monostable circuit 210 which outputs the variable monostable signal at a high level for a prescribed time, a little delayed from the time point where the power transistor 107 of the ignitor 100 is cut off. A power transistor 207 is brought into electric conduction by the monostable signal, and the primary auxiliary coil 209 wound onto an iron core 110 is brought into electric conduction so that the direction of the generated magnetic flux is reverse to the primary coil 109. The power transistor 207 is cut off when an electric-discharge detecting circuit 250 detects the dissipation of the arc discharge electric current of the secondary coil 111.

Description

[Detailed description of the invention]

[Field of Application in Industry-1-] This invention relates to an ignition device for an internal combustion engine, and particularly to a high-energy ignition device. [Prior Art] In recent years, various improvements have been made to ignition systems in order to achieve both reduction in fuel consumption and purification of exhaust gas in automobile engines.In particular, high-energy ignition systems are essential for lean-burn engines. It has become. By the way, current interrupting type ignition devices are commonly used as ignition devices for internal combustion engines. In this type of ignition device, the magnetic flux generated by the primary current of the ignition coil is stored in the iron core, and the spark energy is determined primarily by the energy generated by this stored magnetism. Therefore, larger −
[To obtain energy, make the iron core larger and increase the primary iIt
? It is necessary to increase the size of k or the primary winding, which has the disadvantage of increasing the size of the device. In addition, a D C-DC converter was used to increase the energy of a normal ignition system (for example, GJ JP-A-5
5-98671), and one in which several ignition devices are used and the secondary side of the coil is added together (for example, U.S. Patent No. 3.28 (Figure 5 of the specification of No. 1,809)). The disadvantages of the proposed ignition system are that it requires an expensive high-voltage diode, and that the cost increases significantly as the device becomes larger.Furthermore, the capacitor discharge type ignition device and the current interruption type ignition device of J. Although it has been proposed that the device has 17 feet and 17 holes on the primary side (for example, FIGS. 4 and 6 of U.S. Pat. No. 3,280,809), the device is the same as the above conventional example. The disadvantage is that the ignition coil becomes larger and the cost increases.On the other hand, using a normal ignition coil, the primary coil is
A method has been proposed in which the spark energy is increased by alternating excitation by turning on and off one power transistor (for example, Japanese Patent Application Laid-Open No. 5-4-7030), in which one pair of transistors is turned off. The spark energy of a normal current interrupt type ignition device can be obtained by
The aim is to increase energy by superimposing this energy on the secondary side by turning on the other pair of transistors to generate a voltage twice the turns ratio. [Problems to be Solved by the Invention] However, this device requires expensive PNPN power transistors, 2 N power transistors, and 2 primary diodes, each of which is expensive. Furthermore, in a normal ignition coil, the turns ratio between the primary coil and the secondary coil is about 100 times. (The number of turns in the primary coil cannot be changed.)
, the number of turns of the secondary coil increases, and as a result, the impedance of the secondary coil becomes high, and leakage f1 (resistance becomes worse), performance decreases when the spark plug smolders, and the secondary coil This is because there is a possibility of ignition due to the voltage generated by the engine.In a normal ignition system, the secondary high-voltage output of the ignition coil is connected to each spark plug via a distributor and a high-voltage cord containing a resistor. .Here, the discharge sustaining voltage of each spark plug is about IKν, but a voltage drop occurs due to the voltage being applied to the high-voltage coil 1 with a resistor, the distributor, etc.
The next output needs to have a discharge sustaining voltage of at least 2'V or more in consideration of these voltage drops. Furthermore, the discharge sustaining voltage of the spark plug varies depending on engine rotation and load. In addition, the engine voltage V varies from VB=10 to 16 V depending on the rotational speed and load, which affects the secondary output voltage of the superposition. Therefore, JP-A-5'4-7
As in the example of Publication No. 030, a normal ignition coil (turns ratio 1
00 times) is used, the secondary voltage generated when a pair of transistors conducts] 2Vx I 00=, 1.2
The voltage is about KV, and it is difficult to add energy at this voltage. Considering that the discharge sustaining voltage of the secondary coil output is affected by the engine speed and load, and the secondary output voltage for superposition is also affected by the power supply voltage, such a superposition discharge method The number of turns required is about 200 to 400 times that of the ignition coil. However, making a normal ignition coil have such a high turns ratio has the problems of increased coil impedance and the possibility of sparks flying when the primary coil is energized, as described above. The present invention solves the above-mentioned problems, and aims to provide a high-energy single ignition device that is inexpensive, compact, and generates little heat by adding a simple circuit to a normal current-interrupting type ignition device. It is. [Means for solving the problem] Therefore, the first invention provides an iron core and a wire wound around the iron core.
Next, an ignition coil having a secondary coil. and primary current intermittent means for intermittent primary current of the ignition coil, and generates a high voltage in the secondary coil when the primary current intermittent means interrupts the primary current. , occurs in the primary coil (the primary auxiliary coil is wound around the iron core so that one bundle is in the opposite direction and has a smaller number of turns than the primary coil, and immediately after the current in the primary coil is cut off) a semiconductor switch element for intermittent primary auxiliary current for forming a jmm electric path of the primary auxiliary coil through conduction;
a backflow prevention element that is connected in series with the primary auxiliary current intermittent semiconductor switching element in the energization circuit of the auxiliary coil and prevents reverse current from flowing to the primary auxiliary coil; and an arc of the secondary coil. The present invention provides an ignition device for an internal combustion engine, comprising a discharge detection circuit for detecting a discharge current and cutting off the primary auxiliary current intermittent semiconductor switch when the arc discharge current is substantially extinguished. Further, the second invention includes an ignition coil having an iron core and primary and secondary coils wound around the iron core, and a primary current intermittent means for intermittent the primary current of the ignition coil. a current interruption type ignition device that generates a high voltage in the secondary coil when the primary current is interrupted by a secondary current interruption means; At the same time, the first auxiliary coil is electrically connected to the primary auxiliary coil, which has a smaller number of turns than the primary coil.
a semiconductor switch element for intermittent primary auxiliary current to form an energization circuit for the secondary auxiliary coil; Backflow prevention I that prevents current from flowing in the opposite direction to the coil]
- a variable monostable circuit that emits a variable metastable signal when the current in the primary coil is cut off, and a discharge detection circuit that detects arc discharge current flowing through the secondary coil. The logic between the discharge detection circuit that generates the signal and the discharge detection signal of the discharge detection circuit that records the h'f variable and stable signal of the variable monostable circuit is taken, and this discharge detection signal and 1j; The present invention provides an ignition device for an internal combustion engine, comprising a logic circuit for conducting and switching the semiconductor switching element for primary auxiliary current intermittent only when both the stability signal and the stability signal are generated. The invention of No. 3 includes an ignition coil having an iron core and primary and secondary coils wound around the iron core, and primary current intermittent means for intermittent the primary current of the ignition coil. a current interrupting type ignition device that generates a high voltage in the secondary coil when the primary current is interrupted by the means; By conducting with the primary auxiliary coil, which has fewer turns than the primary coil,
a semiconductor switch element for intermittent primary auxiliary current to form an energization circuit for the secondary auxiliary coil; A backflow prevention element that prevents reverse current from flowing to the primary auxiliary coil;
- a crank angle position detection means that detects up to a predetermined crank angle position near the dead center and generates an angle signal; and detects that an arc discharge current is flowing through the secondary coil and generates a discharge detection signal. A discharge detection circuit, which takes logic between the angle signal of the crank angle position detection means and the discharge detection signal of the discharge detection circuit, and detects the primary signal only when both the discharge detection signal and the angle signal are generated. The present invention provides an ignition device for an internal combustion engine that includes a logic circuit for conducting and disabling a semiconductor switching element for auxiliary current intermittent. [Operation] As a result, in the first invention, when the primary current of the ignition coil 1 is interrupted, a high voltage is induced in the secondary coil by the ignition energy stored in advance in the iron core, and the ignition plaque is lit. Arc current flows. Further, a current flows to the primary auxiliary coil immediately after the primary current is interrupted, and the energy due to the energization of the primary auxiliary coil is added to the arc energy due to the primary current interrupted. Here, since the number of turns of the primary auxiliary coil is smaller than the number of turns of the primary coil, the turns ratio of the primary auxiliary coil and the secondary coil becomes higher than the number of turns of the primary and secondary coils, so that Next auxiliary coil
・A secondary voltage higher than the discharge sustaining voltage of the spark plug is obtained when energized. Also, when the primary current is cut off, the primary sleeve support
The reverse current flowing through the primary coil due to the voltage induced in the coil is prevented by the backflow prevention element Y, and the secondary voltage induced in the secondary coil is reduced when the primary current is cut off. Defense 112. Furthermore, when the arc discharge current in the secondary coil is substantially reduced, the power to the primary auxiliary coil is cut off.
Primary coil ＼Prevents unnecessary current from flowing.Also,
In the second invention, Section 31L In addition to the effects of the first invention, 1
When the current of the next coil is cut off, a variable amount stable signal is generated in the variable monostable circuit, and this variable monostable signal and the main I of the discharge detection circuit are generated.
When both the female electrician detection signal and the female electrician detection signal are generated at 7'C, 1
Next, current flows through the auxiliary coil. Furthermore, in the third invention, in addition to the effects of the first invention,
An angle signal is generated in the crank angle position detection means from the crank angle position when the current of the primary coil coil is cut off to a predetermined crank angle position near the second dead center, and this angle signal and the discharge detection signal of the discharge detection circuit are generated. Current flows through the primary auxiliary coil only when both of these conditions occur. [Example] Hereinafter, the present invention will be explained according to an example shown in the drawings. In the first embodiment shown in FIG. 1, 1 is a battery whose negative terminal is grounded, 100 is an ordinary current interrupting type ignition device, and the high voltage output terminal of the secondary coil 111 of the ignition coil 108 is a high voltage with a resistor. spark plugs 3. to each cylinder via the coils 1-7a to 7e and the discharger 2; 4
．． 5. 6. Next, regarding the conventional current interrupting type fire device 100,
Let me explain briefly. The output signal of the electromagnetic pickup 112, which generates an AC output signal in synchronization with the rotation of the internal combustion engine, is waveform-shaped into a rectangular wave signal by a waveform shaping circuit 113, and then
It is connected through a resistor 102 to the base of a transistor 104, and the base of this transistor 104 is connected through a resistor 103 to the positive terminal (8) of the battery 1. Also, the emitter of this transistor +04 is the battery 1
A power transistor 1 is connected to the nofrus terminal "j' Vs, its collector is grounded through a resistor 105, and the power transistor 1 forms a primary current disconnection Vt-+ stage through a resistor 106.
It is connected to the base of 07. Furthermore, this power 1
- the emitter of the transistor 107 is grounded and its collector is connected via the primary coil 109 of the ignition coil 108 to the positive end YV8 of the battery l; The 200 tJ spark energy increase circuit will now be described in detail. The output terminal of the waveform shaping circuit 113 is a monostable multi-high break 231. ANr) is connected to one input terminal of the circuit 232 and the F/V converter 233. The monostable multi-pie break 231 generates a high-level output with a narrow width of about 50 μs in synchronization with the rise of the output signal of the waveform shaping circuit 113 (when the primary current is cut off). The output of the monostable multivibrator 231 is then transferred to the inverter 234.
is inverted and connected to the other input terminal of the AND circuit 232. As a result, the AND circuit 232 generates a %tj-shaped wave output that rises with a slight delay from the rising edge of the output signal of the waveform vertical circuit 113. The output of this A N r'1 circuit 232 is input to two monostable multi-high breaks 235 and 236. these,
The monostable multivibrators 235 and 236 output high-level output signals with widths of about 2 ms and 3 ms in synchronization with the rise of the output signal of the AND circuit 232 (about 50 μs after the primary current cutoff). Occur. These, qL
Each output of stable multi-high break 235, 236 is A
Each is connected to one input terminal of ND circuits 237 and 238. Furthermore, the F/V converter 233C outputs a DC voltage proportional to the number of input pulses from the waveform shaping circuit 113, that is, the engine speed, and this output is sent to the inverting input terminals of the two comparators 239 and 240. It is connected. The non-inverting input terminals of each of these comparators 239 and 240 are connected to the connection point of the dividing resistors 241 and 242, and to the connecting point of the dividing resistors 241 and 242.
2. '243 connection points, respectively, and these 3
The two dividing resistors 241 to 243 are connected in series with each other,
Connect between constant voltage ■ and ground. Here, the set voltage of the non-inverting input terminal of one comparator 239 is set to a value corresponding to the engine rotational speed of 200 Orpm for each dividing resistor 241.
~243, so the engine speed is 20
A high level output signal is generated only when the rpm is below 0 Orpm. In addition, since the set voltage of the non-inverting input terminal of the other comparator 240 is set to a value corresponding to the engine speed of 1100 Orp by each of the dividing resistors 241 to 243,
A high level output signal is generated only when the engine speed is below 1100 Orp. Gore, comparator 239,2
The output of 40 is connected to the other input terminal of each AND circuit 237. '238
The outputs of are respectively connected to two input terminals of an OR circuit 252, and the output of this OR circuit 252 is a
It is connected to one input terminal of the N10 circuit 244, and the output of this ANr1 circuit 244 is connected to the transistor 202 through the resistor 201. As a result, when the engine speed is below +00Orpm, the O
The output of the R circuit 252 has the same waveform as the output of the monostable multi-high break 236, which has a longer time width, and when the engine speed is ](H10 rpm to 200 rpm, the OR
The output of the circuit 252 has the same waveform as the output of the monostable multi-high break 235, which has a shorter time width, and when the engine speed is 20 rpm or more, the OR circuit 252
output remains at a low level. And F/V converter 2
33. Resistors 241-243. Comparators 239, 24
0. Stable multivibrator 235, 236. AND
The circuits 237, 238 and the ('11 R circuit 252 constitute an i-variant monostable circuit 210. The emitter of the transistor 202 is grounded, and its collector is connected to the base of the transistor 204 via a resistor 203. The emitter of this transistor 204 is connected to the positive terminal 8 of the battery 1, and its collector is grounded via a resistor 205 and connected to the resistor 2.
The power transistor 207 is connected to the base of a power transistor 207, which serves as a semiconductor switching element for intermittent primary auxiliary current, through a terminal 06. The emitter of this power transistor 207 is grounded via a current detection resistor 211, and its collector is connected to the cathode of a diode 208.
The anode of is connected to the positive terminal of the battery via the primary auxiliary coil 209. In addition, the current detection resistor 21
The base-emitter path of a transistor 212 is connected in parallel between the terminals of the power transistor 207, and the collector of the transistor 212 is connected to the base of the power transistor 207. Here, the primary auxiliary coil 209 is wound around the iron core 110-1- so that the magnetic flux is in the opposite direction to that of the primary coil 109, and the primary coil I The turns ratio between 09 and secondary coil III is about 100 times, but the primary auxiliary coil 209 and 2
The turns ratio of the secondary coil 111 is approximately 200 to 400 times. In other words, the constant values of the primary coil 109 and the secondary coil 111 are the same as those of a normal ignition coil, and the primary auxiliary coil 209 has about 1/2 to 1/4 the number of turns of the primary coil 109. Next, the discharge time detection circuit 250 will be described in detail.Dividing resistors 246 and 247 are connected in series between the positive terminal of the battery 1 and the ground.One end of the resistor 248 is connected to the collector of the power transistor 107. connected and the other end is resistor 2
It is grounded via 94. Divided resistance 246.247
The connection point of is connected to the inverting input terminal of the comparator 245, and the connection point of the resistors 248 and 249 is connected to the connection point number 21 of the comparator 2.
It is connected to the non-inverting input terminal A of 45. The output terminal of the comparator 245 is connected to one input terminal of an AND circuit 244 forming a logic circuit.
The output terminal of the OR circuit 241 is connected to the other input terminal Y of , and the output of the ANI′) circuit 244 is connected to one end of the resistor 201 . Next, the operation of the above configuration will be explained. First, the discharge detection circuit 250 and the A N r') circuit 24
4 is not present, and the output signal of the OR circuit 252 is directly supplied to the base of the transistor 202 via the resistor 201. When the output signal of the waveform shaping circuit 113 becomes low level as the engine rotates, the transistor 104 becomes conductive and the power transistor 107 becomes conductive, causing the primary coil 10 to become conductive.
A current flows through 9. Then, at a predetermined ignition timing, the output signal of the waveform shaping circuit 113 becomes high level, and the current in the primary coil 109 is abruptly cut off, so a high voltage is generated in the secondary coil 111, and the 2 and each spark plug 3.4, 5.6 and an arc current flows. So far, the operation is the same as that of a regular current cutoff type ignition system, but when the engine speed is 200 rpm or less, the variable metastable circuit 210 fires for a predetermined time (3 ms) after a slight delay from the time when the power transistor 107 shuts off. or 2m
5) A high-level variable QL stable signal is output, and the power transistor 207 is switched to At1fl[I] for this time.
(Here, the diode 1208 is for preventing backflow from the power 1 to the run transistor 207.) By the way, the primary auxiliary-1 coil 209 is the primary coil IC)
The number of turns is about 1/2 to 1/4 of the number of turns of 9, that is, the turns ratio between the primary auxiliary coil 209 and the secondary coil 111 is 200 to 1/4.
It is about 400 times larger. In addition, the power transistor 207
The coil is wound so that the direction of the magnetic flux generated in the iron core 110 due to the current flowing through the primary auxiliary coil 209 when the power transistor 107 is turned on is opposite to the direction of the magnetic flux due to the current flowing through the primary coil 109 when the power transistor 107 is conductive. ing. Here, in the iron core 110, the direction of the magnetic flux while the current in the primary coil 109 is flowing and the direction of the magnetic flux immediately after the current in the primary coil 109 is cut off are in opposite directions, as is generally known. The direction of the magnetic flux after the primary coil 109 is cut off is the same as the direction of the magnetic flux when the primary auxiliary coil 209 is energized. It is possible to add energy. However, as mentioned above, the discharge maintenance voltage of the spark plug is affected by the engine speed and load, and the secondary voltage due to energization of the primary auxiliary coil 209 is also affected by the battery voltage. The turns ratio between the primary auxiliary coil 209 and the secondary coil 111 is set as follows:
2 higher than the turns ratio (about 100 times) with the next coil Ill
00 to 400 times, a secondary voltage higher than the discharge sustaining voltage of the spark plug can be obtained even when the battery voltage is low. And, the primary coil 109 and the secondary coil 11
1 uses the same as a normal ignition coil, so
: There are no problems such as an increase in coil impedance or flying sparks when energized. Here, in this embodiment, the iron core 1 of the ignition coil 108 is
10, a primary auxiliary coil 209 of about 1/200 to 1/400 of the number of turns of the secondary coil 1 is wound in the opposite direction to the primary coil 109, and a power transistor 207, a reverse current prevention diode 208, and a variable stable four fi42.
It has the excellent feature of being able to approximately double the arc energy with an extremely simple circuit configuration that includes a 10 etc. In addition, even though the primary auxiliary coil 209 used is about 1/2 to 1/4 of the number of turns of the primary coil 109, the DC resistance value of the primary auxiliary coil 209 was determined by using a coil with a small wire diameter. By making the current capacity of the power transistor 207 of the primary auxiliary coil 209 approximately the same as that of the primary coil 109, the current capacity of the power transistor 207 of the primary auxiliary coil 209 is
The current capacity can be made the same as that of the power transistor 107 of No. 09. Here, the primary coil 108, the secondary coil 109.
111 and the primary auxiliary coil 209. As the primary coil 109, the wire diameter is 0.75 am.
Copper wire is wound 280 times, and its DC resistance value is 1.48Ω.
A wire diameter of 0.06 m is used as the secondary coil 111.
- Copper wire is wound 28,000 times and its DC resistance is 3.
5 using Ω, the primary and secondary coils 109, 11
In the case of a normal ignition coil with a turns ratio of 100 times,
As the primary auxiliary coil 209, a cage copper wire with a wire diameter of 0.45 is wound 93 times and its DC resistance value is 1.48Ω, and the turns ratio of the primary auxiliary coil 209 and the secondary coil 111 is approximately 300. It's double. In addition, the current flowing through the primary auxiliary coil 209 is detected by the current detection resistor 211, and when this current exceeds a predetermined value, the transistor 212 is operated in the unsaturated region in the conduction direction, and the base current of the power transistor 207 is increased. By reducing the current, the first and second power transistors 207 are operated in the unsaturated region, and the maximum current flowing through the primary auxiliary coil 209 is controlled at a constant current and limited to a predetermined value. Furthermore, the engine speed is 100 Or
When the temperature is below pm, the primary current is cut off and the
After the elapse of μs, a current is supplied to the primary auxiliary coil 209 for 3 ms to increase the ignition energy to the maximum. When the ignition is relatively poor at 1000 to 200 Orpm, the primary current is cut off and after 50115 lapses, current flows through the primary auxiliary coil 209 for 2 ms to increase the ignition energy by the required amount. The heat generation of the primary auxiliary coil 209 and the power 1 to transistor 207 is reduced by the amount that the time for energizing the secondary auxiliary coil 209 is reduced. When it is above 200 rpm, which has relatively good ignitability, the primary auxiliary coil 209 is not energized.By doing so, the primary auxiliary coil 209 and the power source 207 are prevented from generating heat, and the spark plug is worn out. decrease. Here, 1
The reason for starting the auxiliary current is that the waveform shaping circuit 11
There is a time delay from when the output of 3 rises until the power transistor 107, which intermittents the primary current, cuts off, mainly due to the stray capacitance V between the base and emitter of this power transistor 107, and during this delay time, 1 This is to reliably prevent the ignition energy from decreasing due to conduction of the power transistor 207 that intermittents the auxiliary current.
Even in the case where a monostable multivibrator 231 is used, there is a time delay between the output of the waveform shaping circuit 113 rising and the power transistor 207, which cuts off the primary auxiliary voltage, becoming conductive. Multi-by-break 231. Inverter 234 and AND circuit 2
32 is not necessarily required. Next, the operation and function of the discharge detection circuit 250 will be explained. FIG. 2 is a diagram showing how the discharge time changes because the discharge path at the spark plug changes due to the wind inside the internal combustion engine cylinder. Figure 3 shows the discharge time of the spark plug and the power transistor 2.
07 is a diagram showing the relationship with power consumption, and in FIG. 3,
(1) is the discharge current of the spark plug, (2) is a variable monostable signal for controlling the ignition energy, (3) is the collector current of the power 1 transistor 207, and (4) is the power 1 transistor 2
07 collector voltage, (5) is the power transistor 20
7 represents the power consumption. FIG. 4 is a diagram showing the operation of the discharge detection circuit 250.
) is the discharge current of the spark plug, (2) is the collector voltage of the power transistor 107, (3) is the output waveform of the converter 245 (discharge detection signal), f4) is the variable monostable signal for controlling the ignition energy, (5) represents the collector current of the power transistor 207. -■- In the embodiment described above, the power transistor 207 of the primary auxiliary coil 209 is made conductive by the variable monostable signal of the variable monostable circuit 210, and the variable monostable time is further varied depending on the engine speed to control the ignition energy. is under control. By the way, in an actual vehicle, as shown in FIG. 2, the discharge path at the spark plug changes depending on the airflow within the engine cylinder, so the discharge time (arc time) is constantly changing. As a result, if the power transistor 207 is rendered conductive only by the variable metastable signal, a problem arises in that the power transistor 207 generates abnormal heat. Below is the third reason.
Explain using diagrams. When the power transistor 207 is conductive and the spark plug is receiving discharge current (
1, to t2), the voltage applied to the collector of the power transistor 207 is low due to the back electromotive force VRE from the secondary side, and the power consumption in the power transistor 207 (b in Fig. 3 (5)) is low. part) is small. However, the discharge time of the spark plug changes and becomes shorter than the variable monostable signal.In this case, the power transistor 207 is conducting, but the time during which no discharge current flows through the spark plug (

[2~t
a) is bullish. At this moment, the voltage applied to the collector of the power transistor 207 increases because the back electromotive force V and lE disappears, and the power consumption increases (part C in Fig. 3 (5)).
becomes. Therefore, the above-mentioned problem occurs. Therefore, in the present invention, the power transistor 207
In order to prevent abnormal heat generation, the discharge time of the spark plug is detected, and if that time is shorter than the variable monostable time of the variable monostable circuit 210, the power transistor 207 is shut off when the discharge of the spark plug ends. Discharge detection circuit 2
It has 50. l The method of detecting the discharge time by the discharge detection circuit 250 will be explained below with reference to FIG. As shown in Figure 4 (1), when a discharge current is flowing through the spark plug, the collector of power transistor
A high voltage of 0-30V is generated. Therefore, by comparing this voltage with the voltage set by the dividing resistors 246 and 247 by the comparator 245, the discharge detection signal shown in FIG. 4(3) is obtained. To explain the details of the set voltage, since the waveform shown in FIG. 4(2) is biased by the voltage 18, the threshold voltage V3 is made to depend on the power supply voltage. That is, the threshold voltage 3 (approximately 20 V at 12 volts) of the voltage 2v+ + the adjustment voltage 2 is set by the dividing resistor 246 and 247, and the comparator 245 performs the comparison. The AND circuit 244 calculates the logical product of the discharge detection signal shown in FIG. 4 (3) explained above and the variable monostable signal shown in FIG. is under control. As a result, even if the spark plug discharge time N+~tz) becomes shorter than the variable monostable time (1,~ts), the power transistor 207 is shut off when the spark plug discharge ends, and its heat generation is stopped. Preventing. FIG. 5 shows a second embodiment of the present invention, in which the time constant of the monostable multi-vibration break 235 is continuously changed by the voltage according to the engine speed of the F/V converter 233, and the variable monostable The time width of the variable monostable signal of the stabilizing circuit 210 is continuously decreased as the engine speed increases. FIG. 6 shows a third embodiment of the present invention, in which instead of using the variable metastable circuit 210 in the first embodiment,
The RS flip-flop 261 is set by the output signal of the AND circuit 232, and in synchronization with the rotation of the internal combustion engine,
Position sensor 26 that detects the position near top dead center of the internal combustion engine
2, and a waveform shaping circuit 263 for shaping the output signal of the position sensor 262 and resetting the RS flip-flop 261 near the top dead center of the internal combustion engine.
The Q output signal of the RS flip-flop 261 is supplied to one input terminal of the AND circuit 244. According to this third embodiment, regardless of the engine speed, after the current in the primary coil 109 is cut off, the current is supplied to the primary coil 209 up to the crank angle position near the top dead center. FIG. 7 shows a fourth embodiment of the present invention, in which the electromagnetic pickup 112 is configured so that the falling position of the waveform shaping circuit 113 is approximately at the top dead center, and the output signal of the waveform shaping circuit 113 is In addition to supplying the signal to the inverter 264 of the position detection circuit 21OA, the electronic ignition control circuit 114 electronically controls the ignition timing using the rectangular wave signal of the waveform shaping circuit 113 as a reference signal to generate an ignition signal. The current of the primary coil 109 is controlled intermittently, and the ignition signal of the electronic ignition control circuit 114 is controlled by the 91 stable multi-high break 231 and the A N
r) 4) is supplied to the circuit 232. According to the fourth embodiment, unlike the third embodiment, the position sensor 262 and the waveform shaping circuit 263 are not required as the crank angle position detection circuit 210A. FIG. 8 shows a fifth embodiment of the present invention, in which one end of a resistor 248 is connected to a power transistor
Instead of connecting to the collector of 07, the secondary coil 1]1
A discharge current detection resistor 251 is inserted between one end and the ground, and the connection point between this resistor 251 and the secondary coil 111 is connected to the resistor 24.
8 to directly detect the discharge current. FIG. 9 shows the waveforms of various parts in the fifth embodiment, and the solid line in FIG. (1) tI) A voltage is generated that reaches a maximum and gradually decreases. Dot-dashed line ■ in Figure 9 (1). is a set voltage set to a small value, and this set voltage ■. When the terminal voltage of the discharge current detection resistor 251 is higher, a high level discharge detection signal is generated in the comparator 245 as shown in FIG. 9(2). [Effects of the Invention] As mentioned in the eleven sections below, in the first invention, when the primary current is cut off, the energy from the 1llll current of the primary auxiliary coil is added together, and the number of turns of the primary auxiliary coil is equal to the number of turns of the primary coil. By being smaller, the primary auxiliary coil and the secondary
The turns ratio with the secondary coil is higher than the turns ratio between the primary and secondary coils, and when the primary auxiliary coil is energized, a secondary voltage higher than the discharge sustaining voltage of the spark plug is obtained. In the current interrupting type ignition device, a primary auxiliary coil with a smaller number of turns than the primary = 1 coil, and a primary auxiliary current intermittent means for cutting off current to this auxiliary coil are added to the current interrupting type ignition device by a simple circuit configuration that only adds (j+). It is inexpensive, compact, and has the excellent effect of increasing ignition energy.Also, by substantially reducing the arc discharge current in the secondary coil, unnecessary current is prevented from flowing to the primary auxiliary coil. Therefore, there is an excellent effect that the heat generation of the primary auxiliary current intermittent semiconductor switch and the primary auxiliary coil can be reduced. Since current flows through the primary auxiliary coil only when both the variable monostable signal generated in the variable monostable circuit and the discharge detection signal are generated when the circuit is cut off, the variable monostable circuit remains stable even when the discharge detection signal is generated. 1 when no signal is generated
There is an excellent effect that the heat generation of the primary auxiliary coil and the semiconductor switch for intermittent primary auxiliary current can be further reduced by cutting off the power supply to the secondary auxiliary coil. Furthermore, a third invention is based on the first invention, wherein the angle signal and discharge are generated in the crank angle position detection means from the crank angle position when the current of the primary coil is cut off to a predetermined crank angle position near top dead center. Current flows to the primary auxiliary coil only when both the detection signal and the detection signal are generated.
Even when a discharge detection signal is generated, when the crank reaches a predetermined crank angle position near top dead center, the power to the primary auxiliary coil is cut off to reduce heat generation in the primary auxiliary coil and the semiconductor switch for intermittent primary auxiliary current. This has the excellent effect of reducing wear on the spark plug.

[Brief explanation of the drawing]

Figure 1 is an electric circuit diagram showing the first embodiment of the device of the present invention, Figure 2 (^) is a diagram showing two discharge paths of the spark plug, and Figure 2 (B) is the diagram shown in Figure 2 (8). FIGS. 3 and 4 are waveform diagrams of the discharge voltage and discharge current of the spark plug in each discharge path, FIGS. 3 and 4 are waveform diagrams for explaining the operation of the first embodiment, and FIGS. 5 and 6 are diagrams of the device of the present invention. 2nd and 3rd
FIG. 7 and FIG. 8 are electric circuit diagrams showing the main parts of the fourth and fifth embodiments of the device of the present invention, and FIG. 9 is an electric circuit diagram showing the operation of the fifth embodiment. It is a waveform diagram of each part provided. 100...Current interruption type ignition device, IO2...Power 1 run sister with no primary current intermittent means, 108...
Ignition coil, 109...Primary-1 coil, 110...
Iron core. 111...Secondary coil, 207...Semiconductor switch for intermittent auxiliary current, 208
...Diode 1" forming backflow prevention +l- element, 209.
...Primary auxiliary coil, 21O...Variable Sakae stability circuit, 2
10A...Crank angle position detection circuit forming crank angle position detection means, 244...ANl forming a logic circuit
) circuit, 245... constitutes a comparator: 1 comparator. 25+...h current detection resistor.

Claims (7)

[Claims] (1) It includes an ignition coil having an iron core and primary and secondary coils wound around the iron core, and a primary current intermittent means for intermittent the primary current of this ignition coil, and the primary current intermittent means a current interrupt type ignition device that generates a high voltage in the secondary coil when the primary current is interrupted; a primary auxiliary coil with a smaller number of turns; a semiconductor switch element for intermittent primary auxiliary current that becomes conductive immediately after the current in the primary coil is cut off to form a current-carrying circuit for the primary auxiliary coil; a backflow prevention element that is connected in series with the semiconductor switching element for intermittent primary auxiliary current in the energizing circuit and prevents reverse current from flowing to the primary auxiliary coil; and An ignition device for an internal combustion engine, comprising: a discharge detection circuit for detecting and interrupting the primary auxiliary current intermittent semiconductor switch when the arc discharge current is substantially extinguished. (2) The ignition device for an internal combustion engine according to claim 1, wherein the discharge detection circuit detects an induced voltage generated in the primary coil by an arc discharge current of the secondary coil. (3) The discharge detection circuit is configured such that the voltage at the connection point between the primary coil and the primary current intermittent semiconductor switching element is higher than the power supply voltage and lower than the induced voltage generated in the primary coil by the arc discharge current. The ignition device for an internal combustion engine according to claim 2, further comprising a comparator that compares a set value with a set value and generates a discharge detection signal when the voltage at the connection point is higher than the set value. . (4) The discharge detection circuit compares a discharge current detection resistor connected in series with the secondary coil, a terminal voltage of this discharge current detection resistor, and a set value set to a small value, and The ignition device for an internal combustion engine according to claim 1, further comprising a comparator that generates a discharge detection signal when the terminal voltage of the discharge current detection resistor is high. (5) includes an ignition coil having an iron core and primary and secondary coils wound around the iron core, and primary current intermittent means for intermittent primary current of this ignition coil; a current interrupt type ignition device that generates a high voltage in the secondary coil when the primary current is intermittent; a primary auxiliary coil with a smaller number of turns; a semiconductor switch element for switching on and off the primary auxiliary current to form a current-carrying circuit for the primary auxiliary coil by conducting; a backflow prevention element connected in series with the current intermittent semiconductor switch element to prevent current from flowing in the reverse direction to the primary auxiliary coil; and a variable monostable element that generates a variable monostable signal when current in the primary coil is interrupted. a stabilizing circuit; a discharge detection circuit that detects arc discharge current flowing through the secondary coil and generates a discharge detection signal; and a variable monostable signal of the variable monostable circuit and a discharge detection circuit of the discharge detection circuit. for an internal combustion engine, comprising a logic circuit that takes logic with the signal and makes the primary auxiliary current intermittent semiconductor switching element conductive only when both the discharge detection signal and the variable metastable signal are generated. Ignition device. (6) The ignition device for an internal combustion engine according to claim 5, wherein the time width of the variable metastable signal of the variable monostable circuit decreases as the engine speed increases. (7) includes an ignition coil having an iron core and primary and secondary coils wound around the iron core, and primary current intermittent means for intermittent primary current of the ignition coil; a current interrupt type ignition device that generates a high voltage in the secondary coil when the primary current is interrupted; a primary auxiliary current switching element for forming an energizing circuit for the primary auxiliary coil by conducting with a primary auxiliary coil having a smaller number of turns; a backflow prevention element connected in series with the auxiliary current intermittent semiconductor switch element to prevent reverse current from flowing to the primary auxiliary coil; crank angle position detection means that detects up to a predetermined crank angle position of the secondary coil and generates an angle signal; and a discharge detection circuit that detects that an arc discharge current is flowing through the secondary coil and generates a discharge detection signal. , taking a logic between the angle signal of the crank angle position detection means and the discharge detection signal of the discharge detection circuit, and intermittent the primary auxiliary current only when both the discharge detection signal and the angle signal are generated. An ignition device for an internal combustion engine, comprising a logic circuit for making a semiconductor switch element conductive.