JPS5965569A - Preventive device from over speed for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent an engine from over speed operation surely by using a simple circuit containing a sub-switching element to control a switching element in a no-contact ignition device for delaying the timing of interception of the primary interception current at the time of over speed operation of the engine. CONSTITUTION:In an ignition device to add high voltage to an ignition plug 4 by a current-intercepting no-contact ignition circuit 2 via an ignition coil 3, an over-speed prevention circuit 1 is additionally provided on the ignition circuit 2. This circuit 1 is constructed of a sub-switching element 11 to control a main switching element 19 of the ignition circuit 2, a condenser C13 of a large capacity to enable to charge and discharge positive and negative voltages at the time of operation of the said element 11, a Zener diode ZD10 to control the operation of the said element 11, and others. Operation timings of positive and negative charging/discharging of the C13 are overlapped by the breakover of the ZD10 for controlling the delay angle of the primary interception voltage for the coil 3.

Description

[Detailed description of the invention] The present invention relates to an overspeed prevention device for an internal combustion engine.

Conventionally, a current interrupt type non-contact ignition device, a main switching control element using a power transistor, and a sub-switching control fI using a signal transistor or Zyristor to control the main switching element are used.
- Using the 1j element, ・f ignition coil primary short circuit DC basin conduction.

Shut-off [7 (πl and γl) are provided to intermittently generate a high-energy ignition spark at the spark plug connected to the secondary coil L7.

The present invention provides such a non-contact ignition device π in which the sub-switching control element ? , furthermore, by controlling using a controllable circuit, the cutoff timing of the primary cutoff current is delayed when the engine overspeeds. This provides an engine overspeed prevention device.

Hereinafter, all embodiments of the present invention will be explained in detail.

Figure 1 is a block connection diagram of the overspeed prevention device, where 1 is the overspeed prevention circuit, 2 is the current cut-off type non-contact ignition circuit, 3 is the ignition coil, and 4! ri spark plug,
Specifically, the configurations shown in FIGS. 2 and 6, l! l: It has become.

First, the specific circuit shown in FIG. 2 will be explained.

In the over-rotation prevention circuit 1, reference numeral 5.6 denotes a diode and a resistor which are connected in series with each other to extract a voltage corresponding to the primary current of the ignition coil 3. 7 is a diode, 8.9 is a capacitor and a resistor connected in parallel with each other, 10 is a Zener diode for voltage detection, and γ1. are connected in series fl, and as shown in the figure, they are connected in parallel to the series circuit consisting of the diode 5 and the resistor 6. The line l connecting t is grounded 71. 11 is the capacitor 8
and a signal transistor whose base is connected to the midpoint between the resistor 9 and the Zener diode 1o, and whose emitter is connected to VC at the midpoint between the diode 7, the capacitor 8, and the resistor 9. I'm here. 12.13 is a VC series connection between the emitter and the line t2 connecting the other end of the primary side of the ignition coil 3 and the resistor 6;
With the diode and charge/discharge capacitor, this γ1. A transistor 12 is connected between the diode 12 and the capacitor 13.
The collector of is connected to γI. This capacitor 13
Controls the timing of the primary cut-off current by performing all charging and discharging of positive and negative pressure.

On the other hand, in the non-contact ignition circuit 2, a series circuit of resistors 14 and 15 is connected in parallel to both ends of the primary side of the ignition coil 3, and an auxiliary capacitor 1 is connected to the γL1 resistor 15.
6 and a series circuit consisting of a temperature resistance element 17 and a resistor 18 are connected in parallel 71. ing. 19 is the base resistor 14
, 15 connections! With the transistor connected to the midpoint, this 71.
The collector of 71 . It is connected.

21, 22, and 23 are connected in series] (The power transistor 23 has its collector and emitter connected to lines t, t2vC, XI, and fL as shown in the figure. transistor 21σ
]This is the resistance on the collector side.

Next, the operation of this circuit will be explained.

First, in the engine's normal rotation range π, the voltage of the ignition coil 3 is the line iI-+resistance 14 → diode 1
2→condenser 3→line 121'3 and flow r1. Then, charge the capacitor. Also, at this time, the transistor 1 for the previous issue is OFF''C, and the diode 12 has a backflow prevention function, so the discharge circuit of the capacitor ~ is not formed, and the voltage waveform on the primary side of this ignition coil is As shown in Figure 10 (α),
The voltage waveform of the capacitor 3 is as shown in FIG. 11 (α).

On the other hand, the diode 5 and the resistor 6 pass the negative current v'f from the ignition coil 3 side, and the heavy pressure generated during this period increases proportionally to the jri line as the engine speed increases. It is supposed to be done.

Next, the engine speed increases, and when the engine speed reaches the set speed for overspeed prevention, that is, when the Zener diode IC 17) breaks over, a current gradually flows to the base of the signal transistor 11. ．． start,
Therefore, a current gradually flows between the collector and emitter γ
1. Ru. As a result, capacitor 13π becomes diode 12
And through the transistor 11, a positive voltage is discharged and a negative heavy pressure is charged and discharged 71. , the primary side of the ignition coil 3 and the separation +3 sensor of the capacitor 13 in parallel, the light weight specific a in the positive direction increases.

If the line 12 has a negative potential, the line 12 will flow 71. The negative current flows through capacitor 13 →
Transistor 11 → diode 12 → resistor 14 and capacitor 13 → transistor 11 → diode 7 and current γ
11. The capacitor 13 is charged in the negative direction Q.

On the other hand, the negative charging current is connected to the capacitor 13→Zener diode 10→transistor 11→diode 12 capacitor 13 modified capacitor 13→parallel circuit of resistor 15 and narmistor 17 modified resistor 18→diode 12→
and flow f11, γ1. Then, discharge is performed for a predetermined time with a specific time constant that each element has.

In addition, positive voltage discharge is performed through capacitor 13 → transistor 11 → switching transistor 19 → capacitor 13.
and flow γL1 71. Executed with 1j 11 de constant 71. Ru.

However, in such a circuit, if the negative discharge time constant of the capacitor 13 is selected to be extremely large, 1. Therefore, charging and discharging of positive voltage and charging and discharging of negative voltage are repeated alternately.
．． Then, when the Zener diode 1o breaks over, the positive voltage wave and the negative voltage wave overlap each other, and as shown in Figure 3 π, the blocking position of the positive voltage wave changes by the retard angle θ. (See Figure 10Cb and Figure 11B for details). 1- That is, the Zener diode 10 breaks over at the set voltage.
At the same time, the positive charging/discharging time constant of the electric current starts to increase, and as the collector current of the power transistor 23 is cut off, the current gradually slows down.

Therefore, the ignition timing is also delayed according to 7L. The Rukoto. Here, this delay time θ can be arbitrarily selected by selecting the constants of the Zener diode 10 and the resistor 6. Note that the negative current of the Zener diode 10 due to the following negative current is When the voltage is high, the ignition coil 3σ) to the next side pressure waveform and the capacitor 130 voltage waveform become as shown in FIGS. 10(C) and 11(c), and γl.

γL delay angle θ2 occurs. In addition, the charge/discharge time constant 1 including slow γl, amount it, condenser + jls for each engine rotation range
Depending on the size of capacitor 13'7) g*, you can set arbitrary Vc.
You can do lotus. Figure 4 shows L6 and diode 5.
1, so 71. The voltage V applied to the engine speed N
VC pair (2) shows a state that randomly changes as shown by solid line A.

In that case (2), the signal transistor 11 is used for the first discharge period of the capacitor 13 (in addition, in the case of Cτ, the Zener diode 11 gradually changes the main current cut-off timing from the gray-over starting point). Cτ slow) 7
1θ, this ignition timing characteristic becomes as shown in FIG.

FIG. 6 shows another embodiment of the present invention (also σ). This fL is shown in FIG. 1. For signal j・9727411
In place of 1, a length inlet 24 is connected 17, and even if this circuit has π of 75°, it operates basically the same as the above π, but,
In this case, as soon as the Zener diode 1'10 reaches the breakover voltage, the main current cutoff position is delayed 7! , the signal suddenly jumps by 11 in the direction, and then is gradually delayed continuously at the retard angle θ. This situation is shown in FIG.

In FIGS. 5 and 7, the diagonal lines B and C indicate the over-rotation prevention area, and D represents the normal rotation area.

In addition, Figures 8 and 9 are! ! , 71. Other implementation 1+1 of current interrupt type non-contact ignition circuit 2 1. With something that
In FIG. 8, a PUT element 25 is used in place of the subswitching transistor 19vc (again, the capacitor 1
3 to the positive discharge voltage from line 11+ to the voltage resistor 2
Operate by comparing with the divided voltage Lt value according to 6.27.1. eye,
This is for controlling the discharging operation of the capacitor 13.

Figure 9 shows the Zener diode 28, the size 11, and the star 2.
9. As shown in the figure, the thyristor 29 is made conductive at a constant sleep pressure value of 3 pressures, and the discharge of the capacitor 13 is inhibited.
, is something.

The above details, Attachment F Explanation 1 - π, the present invention τ, B, charging/discharging timing of positive lower pressure of capacitor and negative 7
) Full control of the Zener diode so that the charging and discharging timing of the voltage is fully controlled - By the rotor, the primary cutoff current E for the ignition coil can be controlled (7) Retard control is possible (
7. Therefore, the ignition timing of the internal combustion engine can be delayed to prevent over-revving.

As a result, it is possible to effectively prevent accidents such as seizure of cylinders, pistons, or piston rings due to engine overspeed π: r1. It is something that

[Brief explanation of drawings]

Figure 1 is a block connection diagram of the over-speed prevention device of the present invention, Figure 2 (-1') is a specific circuit diagram of the over-speed prevention device, and Figure 3 is
Figure 11 is a waveform diagram of the primary cut-off voltage, Figure 4 is a breakover voltage characteristic diagram of a Zener diode, Figure 5 is a diagram of ignition timing and characteristics, Figure 6 is a specific circuit diagram of the embodiment of the pond, and Figure 7 is Here is γl, power ignition timing custom diagram, Figures 8 and 9 are γl.
! , is also an example of a current interrupt type non-contact ignition circuit. Figures 10 (CL), (b), and (c) are voltage waveform diagrams at both ends of the ignition coil σ]-next side, Figure 11 (α),
Cb). (c) is a voltage waveform diagram of the capacitor 13. 1... Overspeed prevention circuit, 2... Non-contact ignition circuit, 3
...Ignition coil, 4...Spark plug, 5
... Diode, 6... Resistor, 1o... Zener diode, 11.24... Sub-switching control element, 13... Capacitor. Patent applicant Oppama Kogyo Co., Ltd. Agent
People Patent Attorney Akio Yamamoto
Figure 2 Figure 3 Figure 5 O Figure 6 Off figure O 8 Figure 29 Figure Moon 110 Figure 11

Claims (1)

[Claims] A sub-switching control element that controls the main switching control element is used to conduct and cut off the primary short-circuit DC of the ignition coil connected to the main switching control element (7, the ignition coil (1)). The secondary coil is connected to a pair of spark plugs (with a current-discontinuous type point-contact ignition device that supplies an intermittent spark current), and when the sub-switching control element is operated, a positive voltage is discharged and a negative voltage is discharged. A large capacity capacitor that enables each operation of charging and discharging voltage, and the total charging and discharging time of this capacitor nJCv
+, a time constant circuit that determines the total operation of the sub-switching control element, a Zener diode that controls the entire operation of the sub-switching control element, and a VC differential series connection on the primary side of the ignition coil. When the Zener diode increases accordingly and reaches the set level, the Zener diode completely breaks over, and the capacitor's 11 resistor increases. 1. An over-speed prevention device for an internal combustion engine, in which the trough operation timings of charging and discharging and negative charging and discharging are made to be IF, so that retard control of the primary cutoff field pressure for an ignition coil can be performed.1.