JPS6123664Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a device for stopping an internal combustion engine that drives a load such as a combine harvester in an emergency.

In a device driven by an internal combustion engine, when a clutch or a torque converter is interposed between the engine and the load, the engine may not stop even if the load becomes restrained. In such a case, there is no problem if the operator releases the load restraint state after setting the transmission device to neutral or performing an operation to stop the engine, but if the operator forgets such operation and releases the load restraint state, If you release it, the load will suddenly start rotating, which is dangerous. For example, in agricultural machinery such as combine harvesters, the rice may get caught in the cutter during harvesting, causing only the cutter to stop and the engine to continue rotating. Rice was often removed from the stub without disconnecting it from the engine, and after the rice was removed, the stub was re-driven, resulting in an accident in which the worker's hand got caught in the stub.

An object of the present invention is to provide an internal combustion engine emergency stop device that detects the load state of the engine and automatically stops the engine when the engine becomes overloaded.

The apparatus of the present invention will be explained in detail below with reference to the illustrated embodiments.

Figure 1 shows an embodiment of the present invention, in which 1 is an ignition coil built into a magnetic alternator driven by the engine, and 2 is an ignition coil installed in a cylinder of the engine (not shown). This is a spark plug connected to the secondary coil 1S of the coil. Reference numeral 3 denotes a primary current control unit connected to the primary side of the ignition coil 1. The ignition coil 1 and the primary current control unit 3 constitute an ignition circuit for an internal combustion engine.
The unit 3 includes a transistor 4 whose collector and emitter are connected to one end and the other end of the primary coil 1P of the ignition coil, respectively, a diode 5 which is connected in parallel between the collector and emitter of the transistor 4 with its cathode on the collector side, and Resistors 6 and 7 connect one end of the next coil 1P to the base of transistor 4, and the emitter of transistor 4 and resistors 6 and 7
The control circuit 8 is provided between the connection point of the transistor 4 and the control circuit 8 to control the transistor 4 to be in a cut-off state at the ignition position. The configuration of the control circuit 8 is arbitrary, and any conventionally known configuration can be used as is. For example, if a semiconductor switch such as a transistor or thyristor is provided so that the base current of transistor 4, which flows from the primary coil 1P through resistors 6 and 7 when conductive is bypassed from this transistor, and a semiconductor switch such as a transistor or thyristor is connected to the semiconductor switch at the ignition position. The control circuit 8 can be constituted by a signal supply circuit that provides a signal to cause the control. In this case, the signal supply circuit may be one that provides a conductive signal to the semiconductor switch when the voltage between the collector and emitter of transistor 4 reaches a set value, or one that provides a signal at the ignition position of the engine. A signal generator may be used as the signal source.

In the ignition circuit shown in FIG. 1, a base current flows through the resistors 6 and 7 to the transistor 4 during a half cycle of the voltage induced in the primary coil 1P as the engine rotates, and this transistor becomes conductive. A primary current flows from the primary coil 1P through the collector and emitter of the transistor 4. Next, at the ignition position of the engine where the primary current becomes substantially large, the base current of the transistor 4 is bypassed from this transistor by the action of the control circuit 8, and the transistor 4 becomes cut off. As a result, the current flowing through the primary coil 1p suddenly decreases, and a high voltage is induced in the secondary coil 1s due to the magnetic flux change due to this current change, causing a spark to occur in the spark plug 2 and igniting the engine.

10 is an emergency stop device of the present invention;
A thyristor 11 connected in parallel to the next coil 1p and a capacitor 13 connected in parallel through a resistor 12 between the gate cathode of the thyristor 11
, a battery 14, a first switch 15 that is closed when driving a load after the engine has started, a diode 16, and a resistor 17, so that the voltage of the battery 14 is connected to the first switch 15 and the diode 16. is applied between the gate and cathode of the thyristor 11 through the resistor 17 and the resistor 12.
A second switch 18 for detecting the load condition is connected in parallel to both ends of the capacitor 13, and when the first switch 15 is closed and the second switch 18 is open, the battery 14 is connected to the first switch 15. An ignition signal is supplied to the thyristor 11 through a diode 16 and resistors 17 and 12. In this embodiment, the battery 14,
First switch 15, diode 16, resistor 17
and 12 constitute an ignition signal supply circuit.

In the above embodiment, the first switch 15 is a switch that is closed when driving a load after the engine has started, and this switch closes a clutch or the like provided between the engine and the load in order to drive the load. Alternatively, when the load is driven in conjunction with the load drive mechanism, for example, the clutch is engaged and the transmission changes from a neutral state to one of the drive states (which connects the engine and load). It may also be a switch that closes when the state is switched to (state). The second switch 18 is a switch that detects the load state based on the rotational speed of the load. In this embodiment, it closes when the rotational speed of the load exceeds a set value, and when an overload condition occurs, the rotational speed of the load increases to the set value. It is designed to open when the price reaches its limit. For example, such a switch is
A switch that turns on and off by centrifugal force or a switch that electrically detects the rotational speed of the load and turns on and off according to the detected value can be used. 1st
When the second switch 15 closes, the second switch 18 closes.
However, since there is generally a delay before the rotational speed of the load reaches the set value after the load is connected to the engine, the second switch 18 closes the first switch 1.
The first switch 1 does not close at the same time as 5.
It will close later than 5. Particularly when the second switch is driven by centrifugal force, there is a delay in the operation of the second switch 18 itself.
After the second switch 15 is closed, the second switch 16 is closed.
The time difference until it closes becomes larger.

Fig. 2 is a sequence diagram showing the operation of the above embodiment; Fig. 2a shows the operation of the engine, Fig. 2b and c
show the operations of the first and second switches, respectively. When using the stopping device of the present invention, when starting the engine, the load and engine are disconnected (for example, the clutch is disengaged) and the first switch 15 is opened. After the engine is started at time t ₁ , when the load is driven at time t ₂ , the first
switch 15 is closed. At this time, battery 14
The capacitor 13 is charged through the path from the first switch 15 to the diode 16 to the resistor 17 to the capacitor 13 to the battery 14, and no firing signal is given to the thyristor 11 until the capacitor 13 is completely charged. It's becoming like that. The charging time constant of this capacitor 13 is set to a value that is sufficiently larger than the time difference between when the first switch 15 closes and when the second switch 18 closes. Therefore, at time _t3 when the second switch 18 closes, the ignition signal has not yet been applied to the thyristor 11, and the thyristor 11 is in the cut-off state. When the second switch 18 closes, the battery 14
The ignition signal supplied from the thyristor 11 is bypassed through the switch 18, so even if a forward voltage is applied between the primary coil 1p and the anode/cathode of the thyristor 11, the thyristor 11 will not conduct, and the ignition circuit will operate without any problem. do. Next, at time _t4 , when an overload condition occurs and the load stops, the second switch 18
is opened and the capacitor 13 is charged again. When charging of the capacitor 13 is completed at time _t5 , an ignition signal is supplied to the thyristor 11, and the thyristor 11 becomes conductive during a half cycle in which the induced voltage of the primary coil 1p is ignited. Therefore, the primary coil 1p is substantially short-circuited by the thyristor 11, no ignition is performed, and the engine is stopped. Next, at time _t6 , the first switch 15 is opened, the abnormal load condition is removed, and the engine is restarted at time _t7 . Then, at time _t8 , the load is again driven and the first switch 15 is closed, and at time _t9
At , the second switch 18 is closed and the emergency stop device is held immobile.

When using the stopping device of the present invention, when the engine is started, if the load is connected to the engine (the load is driven by the engine) and the first switch 15 is closed, the engine starts. cannot be started. Therefore, when starting the engine, or when restarting the engine after removing an abnormality in the load in the case of an emergency stop of the engine, be sure to disconnect the load from the engine and open the first switch 15. After the engine is started or restarted, the load is coupled to the engine, such as by connecting a clutch, so that the load is driven by the engine.

Generally, when an engine starting operation is performed correctly, the load is disconnected from the engine at the time of the starting operation, and after the engine starts, the load is brought into a state where it is driven by the engine. If the starting operation is performed correctly in this way, there will be no problem, but if the engine is started with the load connected to the engine by mistake, in this case, if the engine starts, the load will suddenly start rotating. This is extremely dangerous. By providing the stopping device of the present invention, the engine cannot be started when the load is ready to be driven by the engine as described above, so that such a dangerous situation can be avoided.

Ignition circuits for internal combustion engines are not limited to the above examples, but include capacitor charge/discharge type ignition circuits,
Any type of ignition circuit, such as a contact type ignition circuit using a circuit breaker, can be used. and thyristor 11
may be connected in parallel to the components of the ignition circuit that stop the ignition operation if short-circuited. However, in this case, a voltage that can forward bias the anode and cathode of the thyristor during the ignition operation must be generated across the components to which the thyristor is connected in parallel.

In the above embodiment, the battery 14 is used as a power source for supplying the ignition signal to the thyristor, but the induced voltage of the primary coil 1p, or another power generation coil provided within the magnet generator may also be used.

Further, in the above embodiment, the second switch 18 is connected in parallel between the gate cathode of the thyristor, but it opens when the rotational speed of the load is above the set value, and when it becomes less than the set value (overload). A switch that closes when the thyristor is under load can also be used as a second switch. In this case, the second switch 18 may be inserted in series with the gate-cathode circuit of the thyristor.

In the embodiment shown in Fig. 1, if the part surrounded by the chain line 19 is put into a case and made into a unit by casting or molding with resin and pulling out the necessary terminals, the existing Can be easily installed on equipment.

As described above, according to the present invention, when an abnormality occurs in the load, it is possible to short-circuit a part of the ignition circuit using the thyristor and stop the engine, thereby reliably preventing accidents caused by operator carelessness. be able to. In addition, a capacitor was connected in parallel between the gate and cathode of the thyristor to delay the supply of the firing signal to the thyristor when the first switch was closed. It is possible to prevent the thyristor from becoming conductive until the second switch performs an operation to block the supply of the ignition signal to the thyristor, thereby preventing any hindrance to engine operation when the load is normal. Never. Furthermore, by using the stopping device of the present invention, it is possible to prevent the engine from starting when an engine starting operation is performed in a state where a load could be accidentally driven by the engine. This has the advantage of avoiding dangerous situations such as those caused by rotation of the load.

[Brief explanation of the drawing]

FIG. 1 is a connection diagram showing one embodiment of the present invention, and FIGS. 2a to 2c are sequence diagrams showing the operation of the embodiment of FIG. 1. DESCRIPTION OF SYMBOLS 1... Ignition coil, 2... Spark plug, 3... Primary current control unit, 10... Internal combustion engine emergency stop device,
DESCRIPTION OF SYMBOLS 11... Thyristor, 12, 17... Resistor, 13... Capacitor, 14... Battery, 15... First switch, 16... Diode, 18... Second switch.

Claims (1)

[Claims for Utility Model Registration] A thyristor connected in parallel to a component of an ignition circuit for an internal combustion engine that stops ignition operation when short-circuited, and a thyristor that operates a load driven by the internal combustion engine. an ignition signal supply circuit that has a first switch that is closed when the thyristor is closed, and supplies an ignition signal to the gate of the thyristor while the first switch is closed; and a gate-cathode circuit of the thyristor. are provided in parallel or in series, and prevent the supply of the ignition signal to the thyristor when the rotational speed of the load exceeds a set value, and when the rotational speed reaches the set value. a second switch that allows the firing signal to be supplied to the thyristor; and a second switch that is connected in parallel between the gate cathode of the thyristor and is supplied through the first switch when the first switch is closed. and a capacitor that is charged at a constant time constant by an ignition signal from the thyristor and blocks the supply of the ignition signal to the thyristor while being charged, and the charging time constant of the capacitor is determined by the time when the first switch is closed. An internal combustion engine emergency stop device, characterized in that the internal combustion engine emergency stop device is set to be sufficiently longer than the time it takes for the second switch to enter a state allowing supply of the ignition signal.