JPS6149505B2 - - Google Patents

Description

Detailed Description of the Invention The present invention relates to an improved structure of an ignition system for an internal combustion engine, and particularly in a multiple ignition system that ignites at the ignition timing and then performs high-frequency multiple ignition for a predetermined period of time, the present invention relates to an improved structure of an ignition system for an internal combustion engine. This system detects the secondary current and stably performs multiple ignitions.

In conventional ignition systems, multiple ignitions are performed at preset time intervals, so the secondary current of the ignition coil due to the discharge phenomenon of the ignition plug installed in the combustion chamber of the internal combustion engine is reduced. There were fluctuations, resulting in instability of the multiple ignition function. That is, as is well known in the art, it is believed that fluctuations in the secondary energy of the ignition coil are caused by discharge phenomena within the cylinders of the internal combustion engine. Furthermore, when observing the discharge pattern of the secondary current of the ignition coil on an engine bench, the discharge patterns can be roughly divided into A, B, and C, as shown in Figure 1b (Fig. 1a). is the primary current of the ignition coil). According to these fluctuation patterns, as shown in Figure 2b, when the primary current is applied to the ignition coil at point B on the time axis, the electromagnetic energy stored on the secondary side of the ignition coil at point B As shown in A, B, and C, the current rises suddenly from the O level, and the current values become I ₀ , I _{0 ′} , and I ₀ ″, and at point C, the current values of I ₁ , I ₁ ′, and I ₁ ″ are different. becomes the current value. Therefore, if at point C,
When the primary current is interrupted, the secondary current becomes a value corresponding to the primary current I ₁ , I ₁ ′, I ₁ ″ at the time of interruption, and multiple ignitions after point C are stable in the patterns of A, B, and C. Therefore, instability exists in the conventional ignition system for multiple ignition internal combustion engines (Fig. 2a is different from Fig. 1b).
(corresponds to the secondary current waveform of ).

Furthermore, as previously described in Japanese Patent Application Laid-Open No. 50-58430, the primary current of the ignition coil is detected, and each time the primary current reaches a predetermined value, the primary current is interrupted for a certain period of time to generate multiple ignitions. Something to do is being considered. However, even this method has the problem of not being able to eliminate fluctuations in secondary energy caused by discharge phenomena within the cylinders of the internal combustion engine.

Conventionally, as described in Japanese Patent Application Laid-Open No. 53-90531, in a device that ignites only once at one ignition timing, the duration of the secondary current of the ignition coil is detected and the next one of the ignition coil is It has also been considered that the duration of the secondary current is kept approximately constant by controlling the primary interrupting current value in the ignition cycle. However, since this method also controls the primary cut-off current value in the next ignition cycle, it cannot deal with fluctuations in the secondary energy in the current ignition cycle, and it is difficult to stabilize the primary and secondary currents in multiple ignitions. cannot be applied at all.

Therefore, an object of the present invention is to stabilize the multiple ignition function by reducing fluctuations in each primary and secondary current at the time of multiple ignition.

Therefore, in the present invention, a secondary current detection resistor is inserted between one end of the secondary winding of the ignition coil and the ground, and whenever the secondary current detected by the secondary current detection resistor becomes less than a predetermined value. , an output signal for causing the primary current to flow through the multiple ignition control circuit is repeatedly generated only for a predetermined period of time.

As a result, even if the discharge pattern of the secondary current changes due to a discharge phenomenon in the cylinder of an internal combustion engine, the supply of primary current is restarted every time the secondary current falls below a predetermined value for a predetermined period of time. After each electromagnetic energy is stored, the primary current is interrupted and the discharge of the secondary current is initiated. In this way, the supply of the primary current is restarted in response to the discharge state of the secondary current, and the amount of jump in the primary current caused by the electromagnetic energy at the time of starting the supply of the primary current also becomes approximately constant.

The present invention will be described below with reference to embodiments shown in the drawings. In FIG. 3, reference numeral 8 denotes a known ignition signal generation device, which is comprised of an ignition timing detection device using an electromagnetic pickup or an electronic advance circuit having a function of generating an ignition signal. Reference numeral 9 denotes a signal processing circuit which receives the ignition signal from the ignition signal generator 8, generates electrical on/off signals, and generates a predetermined signal waveform. 6 receives an electric signal corresponding to the secondary current of the ignition coil 5 detected by the ignition coil secondary current detection resistor 1a, and when the secondary current reaches a predetermined value, the monostable multivibrator circuit ignites for a predetermined T ₂ hours. It has the function of issuing a coil energization signal to ensure sufficient primary current required for the next ignition, and has the function of generating a coil energization signal after the ignition timing from the signal processing circuit 9 _.
This is a multiple ignition control circuit with a monostable multivibrator circuit for performing multiple ignition only for a certain period of time. 7 is a logic circuit which takes the logical sum of the output signals from the signal processing circuit 9 and the multiple ignition control circuit 6 and generates an on/off signal for the power transistor 16 for multiple ignition; 1 is the primary winding of the ignition coil 5; A power transistor 1b having a function of intermittent primary winding current flowing through the wire 5a, its voltage protection element 1C, and an ignition coil secondary current detection resistor 1a.
This is an output circuit consisting of. The ignition coil 5 has a primary winding 5a, a secondary winding 5b, and an ignition coil external resistor 5c. 2 is the ignition switch,
3 indicates a battery, and 4 indicates a path from the ignition plug or ignition coil secondary terminal to the ignition plug via the distributor.

Next, a detailed circuit of the main part of the block diagram shown in FIG. 3 is shown in FIG. In FIG. 4, the multiple ignition control circuit 6 includes an AND circuit 6a, monostable multivibrators 6b and 6c, a transistor 6d, and an operational amplifier 6.
e, resistance 6f, 6g, 6h, 6i, 6k, 6l,
6n, 6o, 6q, 6r, Zener diode 6
It is composed of capacitors 6m and 6p. The logic circuit 7 includes an OR circuit 7a, resistors 7b and 7d, and a transistor 7c.

Next, the operation of the above configuration will be explained.
As the internal combustion engine rotates, an ignition signal generating device 8 consisting of an ignition timing detecting device using an electromagnetic pickup generates an alternating current signal as shown in FIG. 5A. This signal is then waveform-shaped by the signal processing circuit 9 to obtain a rectangular wave signal as shown in FIG. 5B. This rectangular wave signal is applied to the base of the power transistor 1b via the logic circuit 7, and when the output signal of the signal processing circuit 9 becomes 1 level, the power transistor 1b becomes conductive and the primary current of the ignition coil 5 is changed to It begins to flow like this. Then, when the output signal of the signal processing circuit 9 becomes O level at point S in FIG. A secondary current flows through the secondary current detection resistor 1a as shown in FIG. 5c, and an ignition spark is generated in the ignition plug 4. Here, this secondary current is detected by the secondary current detection resistor 1a, and compared with the reference current shown by α in FIG. 5c by the operational amplifier 6e. The output signal 6e becomes 1 level, transistor 6d becomes conductive, and a 1 level output signal with a predetermined time width _T2 is generated in the monostable multivibrator circuit 6c as shown in FIG. 5F. Further, the monostable multivibrator 6b receives the rectangular wave output from the signal processing circuit 9, and when this rectangular wave output reaches the O level, it generates a 1 level output with a predetermined time width _T0 as shown in FIG. 5E. and,
By ANDing the output signals of the bistable multivibrator circuits 6b and 6c using the AND circuit 6a, and ORing the output signal of the AND circuit 6a and the output signal of the signal processing circuit 9 using the OR circuit 7a. , the output of this OR circuit 7a is shown in FIG.
The result will be as shown below. However, this OR circuit 7
By controlling the primary current of the ignition coil 5 by the output of the ignition coil 5, the secondary current of the ignition coil 5 is
As shown in FIG. C, during the T ₀ period, each time the secondary current reaches a predetermined value α, the discharge is stopped only for a predetermined period T ₂ and the discharge is repeated again, resulting in multiple ignition. Here, the discharge period T ₁ is determined (varies) depending on the secondary current value, and in this way, whenever the secondary current value becomes constant, the primary current is passed and the discharge of the secondary current is stopped. This makes it possible to stabilize the multiple ignition function by reducing fluctuations in the secondary current during multiple ignition discharge.

In addition, in the embodiment described above, the ignition coil 5
A known constant current circuit that controls the power transistor 1b may be combined in order to make the primary current value at the time of interruption a constant current regardless of the battery voltage, and when such a constant current circuit is combined, this constant current control It is even better if the output signal width shown by _T3 in FIG. 5B of the signal processing circuit 9 is changed according to time.

Further, the operating time of the monostable multivibrator 6c shown by T2 in FIG. _5F may be controlled to be short when the battery voltage is high and long when the battery voltage is low. Instead of determining a predetermined operating time using the stable multivibrator 6c, the primary current value is detected and when the primary current value exceeds a predetermined value, the supply of the primary current is stopped, that is, the secondary current is stopped. The operation may be repeated in which the primary current is restarted when the primary current becomes less than a predetermined value, and the primary current is stopped when the primary current becomes equal to or more than the predetermined value due to the restart of the current.

As described above, in the present invention, each time the secondary current detected by the secondary current detection resistor becomes equal to or less than a predetermined value, an output signal is multiplied to cause the primary current to flow in the ignition coil only for a predetermined period of time. Because it is repeatedly generated in the primary ignition control circuit, the primary current is restarted as soon as the secondary current falls below a predetermined value, and after the secondary current is cut off for a predetermined period of time, the secondary current is discharged again. At the same time, the jump amount of the primary current caused by electromagnetic energy at the start of primary current energization can be kept almost constant.
This makes it possible to reduce fluctuations in each primary and secondary current at the time of multiple ignitions and stabilize the multiple ignition function. It is possible to stabilize the ignition function, and also to sufficiently stabilize the multiple ignition function against various unstable factors in the circuit from the ignition coil to the spark plug. It has the excellent effect of being able to reliably ignite the energy.

[Brief explanation of the drawing]

1 and 2 are waveform diagrams of various parts to explain the operation of the conventional device, FIGS. 3 and 4 are block diagrams and detailed electrical circuit diagrams of essential parts showing an embodiment of the device of the present invention, and FIG. FIG. 4 is a waveform chart of various parts for explaining the operation of the apparatus shown in FIGS. 3 and 4. FIG. 1a... Secondary current detection resistor, 1b... Power transistor, 5... Ignition coil, 5a... Primary winding, 5b... Secondary winding, 6... Multiple ignition control circuit, 7... Logic circuit , 8... Ignition signal generator.

Claims (1)

[Claims] 1. An ignition signal generator that generates an ignition signal in accordance with the rotation of an internal combustion engine, an ignition coil having a primary winding and a secondary winding, and one end of the secondary winding of the ignition coil. A secondary current detection resistor inserted between the secondary current detection resistor and the ground, and each time the secondary current detected by the secondary current detection resistor becomes equal to or less than a predetermined value, the primary current is energized to the ignition coil only for a predetermined period of time. a multiple ignition control circuit that repeatedly generates an output signal for the ignition signal generation circuit; a logic circuit that takes a logic between the output signal of the multiple ignition control circuit and the output signal of the ignition signal generation circuit; A multiple ignition device for an internal combustion engine, comprising a power transistor for intermitting the primary current of the ignition coil according to the timing. 2. The internal combustion engine according to claim 1, wherein the multiple ignition control circuit includes a monostable circuit that is triggered every time the secondary current becomes equal to or less than a predetermined value and generates an output signal with a predetermined time width. Engine multiple ignition device. 3. The predetermined time period of the output signal for energizing the primary current of the multiple ignition control circuit ends each time the detected primary current of the ignition coil exceeds a predetermined value. A multiple ignition device for an internal combustion engine as described in .