JPH0212256Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention misfires the engine when the level of lubricating oil (engine oil) in the internal combustion engine falls below the permissible lower limit value to warn of a drop in the oil level. This invention relates to an oil level warning device for internal combustion engines.

[Summary of the invention] This invention reduces internal combustion by substantially short-circuiting the ignition power supply coil by making the coil short-circuiting thyristor conductive when the oil level falls below the allowable lower limit and the oil level detection switch performs a detection operation. In an oil level warning device for an internal combustion engine that warns of low oil level by causing the engine to misfire, a transistor switch circuit is triggered by the voltage obtained across a current limiting element connected in series with a coil short circuit thyristor. By driving the light-emitting display means through the transistor switch circuit with the output of the battery, the light-emitting display means can be driven in synchronization with the operation of the coil shorting thyristor with a simple circuit configuration, and the engine can be activated due to a drop in the oil level. This makes it possible to clearly indicate that a misfire has occurred.

[Prior Art] When the oil level of an internal combustion engine falls below a permissible lower limit, it is necessary to immediately stop the engine and take measures such as replacing or replenishing the engine oil in order to prevent the engine from seizing up.

As a device to warn that the oil level has fallen below the permissible lower limit, an oil level detection switch that performs a detection operation when the oil level has fallen below the allowable lower limit is installed, and when the switch performs the detection operation, Some devices display a drop in oil level by lighting up a light-emitting display means such as a light-emitting diode or a lamp. However, simply displaying a drop in the oil level is dangerous because the engine may continue to operate if the display is overlooked. In particular, in general-purpose engines such as generator-driven engines, it is not possible to constantly monitor the engine status, so simply displaying a drop in the oil level as described above cannot serve the purpose of warning. There are many.

Therefore, for internal combustion engines that are ignited by a non-contact ignition device that uses an ignition power coil installed in a magnet generator as a power source, it is necessary to short-circuit the coil when the oil level falls below the allowable lower limit and the oil level detection switch closes. A warning device has been proposed in which the ignition operation is stopped by making a thyristor conductive and thereby substantially short-circuiting the ignition power supply coil. With this configuration, the engine is stopped when the oil level becomes less than the allowable lower limit value, so it is possible to prevent the engine from being operated with the oil level remaining low and being damaged.

[Problems to be solved by the invention] Conventional oil that causes the engine to misfire by causing a coil shorting thyristor to conduct when the oil level detection switch performs a detection operation to substantially short circuit the ignition power supply coil. In the level warning device, when the coil short-circuit thyristor is conductive, the output supplied from the ignition power supply coil through the thyristor is used to drive a light-emitting display means such as a light-emitting diode, and the light emission from the light-emitting display means indicates the oil level. It was designed to display that the value has fallen below the allowable lower limit. However, if the coil short-circuit thyristor becomes conductive and the engine misfires, the engine speed will rapidly drop and the output voltage of the ignition power supply coil will drop. It was not possible to brightly light up the light emitting display means, and it was not possible to clearly display that the oil level had fallen below the allowable lower limit. In particular, when the engine speed is low, such as when the engine is restarted after it has stopped, a sufficiently high voltage cannot be induced in the ignition power supply coil, so the light-emitting display means cannot clearly emit light. First, it was not possible to clearly notify the driver that the engine had misfired due to a drop in the oil level.

[Means for Solving the Problems] As shown in FIG. 1 showing an embodiment of the present invention, the present invention includes an ignition power supply coil 1 that generates an alternating current voltage in synchronization with the rotation of an internal combustion engine, and an ignition power supply coil 1 that generates an alternating current voltage in synchronization with the rotation of an internal combustion engine. coil 1
Ignition system IG for internal combustion engines driven by the output of
and an oil level detection switch 2 that closes when the engine lubricating oil level falls below the allowable lower limit.
4, a coil short circuit thyristor 30 connected in parallel to the ignition power supply coil 1, and a trigger circuit T that triggers the thyristor 30 when the oil level detection switch 24 is closed. The object is an oil level warning device for an internal combustion engine that warns of a drop in oil level by substantially short-circuiting an ignition power source coil 1 using a thyristor 30 to cause the engine to misfire when the oil level falls below a permissible lower limit value.

In this invention, the coil short circuit thyristor 3
Current limiting element 31 connected in series with 0
and a transistor switch circuit 41 for driving a light-emitting display means that is turned on by being triggered by the voltage obtained across the current limiting element 31 when the coil short-circuiting thyristor 30 is turned on. A light emitting display means that lights up when the transistor switch circuit 41 is conductive is provided.

[Operation of the invention] In the above configuration, when the oil level of the engine becomes less than the allowable lower limit value and the oil level detection switch 24 performs a detection operation, the coil short circuit thyristor 30 is triggered, so the thyristor 30 becomes conductive. The output of the ignition power supply coil 1 is substantially short-circuited. Therefore, the ignition system stops operating and the engine stops. When the coil short-circuiting thyristor 30 becomes conductive, a voltage is induced across the current limiting element 31, which triggers the transistor switch circuit 41 for driving the light-emitting display means to conduct, causing a voltage to flow from the battery through the transistor switch circuit 41 to the light-emitting display means. When energized, the light emitting display means emits light.

Since the light-emitting display means is energized from the battery, the light-emitting display means can emit light with sufficient brightness while the engine is rotating, and a clear display can be provided.

In addition, the transistor switch is triggered by the voltage across the current limiting element connected in series with the coil shorting thyristor to drive the light emitting display means. It is possible to obtain an oil level warning device for an internal combustion engine that can drive the light emitting display means in synchronization with the operation of the engine, and can provide a clear display with a simple structure.

[Embodiments] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows an embodiment of the present invention. In the figure, 1 is an ignition power coil disposed in a magnetic alternator driven by an internal combustion engine (not shown). , induces an alternating current voltage in synchronization with the rotation of the engine. Of the output voltages of both half cycles generated by the ignition power supply coil 1, the output voltage V1 of the positive half cycle is used to operate the ignition device, and the output voltage V2 of the negative half cycle is used to operate the oil level warning device. used to make

One end of the ignition power supply coil 1 is grounded, and the non-grounded terminal A of the ignition power supply coil is connected to the collector of an NPN transistor 3 through a diode 2 with its anode directed toward the terminal A side. The emitter of the transistor 3 is grounded, and the base is connected to the other end of a resistor 4 whose one end is grounded. The terminal A is also connected to one end of the primary coil 5a of the ignition coil 5, and the other end of the primary coil is connected to the anode of a thyristor 6 whose cathode is grounded. The anode of the diode 7 is connected to the anode of the thyristor 6, and the cathode of the diode 7 is connected to the base of the transistor 3. A resistor 8, a diode 9 with its anode facing the ground, and a signal coil 10 are connected in parallel between the gate and cathode of the thyristor 6. The signal coil 10 is provided in a signal generator (not shown) and supplies an ignition signal to the thyristor 6 at the ignition timing of the engine. Both ends of the secondary coil 5b of the ignition coil 5 are connected to the non-ground terminals of spark plugs 11 and 12 attached to different cylinders of the engine, respectively, and when a high voltage is induced in the secondary coil 5b, the spark plugs 11 and 12 Sparks are starting to appear at the same time.

Diode 2, transistor 3, resistor 4, ignition coil 5, thyristor 6, diode 7, resistor 8, diode 9, signal coil 10, and spark plugs 11 and 12 constitute a transistor-controlled current interrupt type ignition device IG for an internal combustion engine. has been done.
In this ignition device, when the ignition power supply coil 1 outputs a positive direction voltage V1, a base current flows through the diode 7 to the transistor 3, making the transistor conductive, and connecting the exciter coil 1 to the diode 2 and the collector-emitter of the transistor 3. Short circuit current flows through. When the signal coil 10 generates a signal at an ignition timing set near an angle at which this short-circuit current becomes sufficiently large, the thyristor 6 becomes conductive, and the base current to the transistor 3 is bypassed from the transistor 3. Therefore transistor 3
is cut off, and the short-circuit current flowing through the ignition power supply coil 1 is cut off. This induces a high voltage in the ignition power supply coil 1, and this voltage is further boosted by the ignition coil 5, causing the spark plugs 11 and 12 to
is applied to Therefore, sparks are produced in both spark plugs and the engine is ignited. Furthermore, spark plugs 11 and 1
When one of the two cylinders to which spark plugs 11 and 12 are installed is at the ignition timing, the other is in a stroke (e.g. exhaust stroke) that does not cause any problem even if a spark occurs, and the spark plugs 11 and 12 At the same time, even if a spark occurs, it does not interfere with engine operation in any way.

The non-ground terminal A of the ignition power supply coil 1 has
One end of the resistor 20 is connected, and the other end of the resistor 20 is connected to the cathode of the diode 21. The first capacitor 2 is connected to the anode of the diode 21.
The other end of the capacitor 22 is connected to the cathode of the first capacitor charging diode 23. An oil level detection switch 24 is connected between the anode of the diode 23 and ground, and a resistor 25 is connected in parallel between one end of the capacitor 22 and ground. Further, a Zener diode 26 with an anode facing the diode 21 side is connected in parallel to both ends of the capacitor 22. The oil level detection switch 24 used in this embodiment is a contact type or non-contact type switch that detects the level of lubricating oil in the engine and closes when the oil level falls below the allowable lower limit.

The anode of a second capacitor charging diode 27 is connected to the connection point between the first capacitor 22 and the diode 23, and the second diode 28 is connected between the cathode of the diode 27 and ground. The non-ground terminal of the capacitor 28 is connected to the gate of a coil shorting thyristor 30 via a resistor 29, and the anode of the thyristor 30 is connected to the non-ground terminal A of the ignition power supply coil 1. The cathode of the thyristor 30 is connected to a ground line via a resistor 31 and to the anode of a diode 32, and the cathode of the diode 32 is connected to the gate of the thyristor 30.

The resistance value of the resistor 31 is a sufficiently small value so that when the thyristor 30 becomes conductive, the ignition power supply coil 1 can be substantially short-circuited (to the extent that the transistor 3 is not rendered conductive) through the series circuit of the thyristor 30 and the resistor 31. is set to .

In this embodiment, resistors 20, 25 and 29
, diodes 21, 23, 27, and 32, capacitors 22 and 28, oil level detection switch 24, and Zener diode 26 constitute a trigger circuit T that triggers the thyristor 30.

The anode of a diode 33 is connected to the non-grounded terminal of the resistor 31, and a capacitor 34 is connected between the cathode of the diode 33 and the ground.
The base of an NPN transistor 36 is connected to the non-grounded terminal of the capacitor 34 via a resistor 35.
The emitter of transistor 36 is grounded.
A resistor 3 is connected between the base and emitter of the transistor 36.
7 are connected in parallel, and one end of a lamp 38 serving as a light emitting display means is connected to the collector of the transistor 36. The other end of the lamp 38 is connected to the positive electrode of a battery 39 whose negative electrode is grounded, and diodes 40 whose cathodes are directed toward the positive electrode side of the battery are connected in parallel to both ends of the lamp 38. In this example,
The transistor 36 and the resistors 35 and 37 constitute a transistor switch circuit 41, and the transistor switch circuit, the diode 33, the capacitors 34 and 40, the lamp 38, and the battery 39 constitute a display circuit 42.

Next, the operation of the above embodiment will be explained. Assuming that the oil level is now below the allowable lower limit and the oil level detection switch 24 is closed, when the ignition power supply coil 1 generates a negative half-cycle output voltage V2, the ignition power supply coil 1 causes the oil level detection switch 24 to close. 1 capacitor charging diode 2
3. The first capacitor 22 is charged to the Zener voltage of the Zener diode 26 with the illustrated polarity via the first capacitor 22, the diode 21, and the resistor 20. When the output voltage V2 of the negative half cycle of the ignition power supply coil 1 becomes lower than the charging voltage of the capacitor 22, the charge of the capacitor 22 is transferred to the diode 27, the second capacitor 28, the resistor 25,
The second capacitor 28 is charged by discharging through the path of the capacitor 22 . Each time the first capacitor 22 is charged and charge is transferred from the first capacitor to the second capacitor 28, the terminal voltage of the second capacitor 28 increases. When the transfer of charge from the first capacitor 22 to the second capacitor 28 is repeated several times, the second capacitor 2
8 reaches the level required to trigger the thyristor 30. Here, the capacitor 28 is discharged at a predetermined discharge time constant between the resistor 29 and the gate cathode of the thyristor 30 and through the resistor 31, but this time constant is such that the discharge current of the capacitor 28 reaches the positive half cycle of the ignition power supply coil 1. Set it to continue. Therefore, when the ignition power supply coil 1 generates a positive half-cycle voltage V1, the thyristor 3
0 becomes conductive and short-circuits the ignition power supply coil 1. This prevents the transistor 3 from conducting, so no ignition is performed and the engine misfires. Once the thyristor 30 is conductive, the capacitor 28 is connected through the thyristor 30, the diode 32, and the resistor 29.
Since the charge is replenished in the thyristor 30, the thyristor 30 becomes conductive every time the ignition power supply coil 1 generates a positive half-cycle voltage and continues to cause the engine to misfire. The engine is therefore stopped and the engine is prevented from seizing up due to the low oil level.

When the oil level detection switch 24 is closed and the thyristor 30 is conductive, a voltage appears across the resistor 31, so a base current flows through the transistor 36, making the transistor 36 conductive, and the lamp 38 and the transistor 36 are connected from the battery 39 to the lamp 38 and the transistor 36. A current flows between the collector and emitter, lighting the lamp 38. This lamp has ignition power coil 1
A positive half-cycle voltage is induced in thyristor 3.
0 lights up every time 0 becomes conductive, and the output voltage of the positive half cycle of the ignition power supply coil 1 disappears, and the thyristor 3
Since the light goes out when the thyristor 30 becomes conductive and causes the engine to misfire, the lamp 38 turns off when the engine is rotating and the ignition power coil 1 turns off.
It will flash periodically while a voltage is induced in the oil valve, indicating that the oil level is below the permissible lower limit. Furthermore, since a sufficiently large current can be passed through the lamp 38 from the battery, the brightness of the lamp can be sufficiently increased, and the display can be clearly displayed.

In the above embodiment, the charge charged to the first capacitor 22 can be adjusted by adjusting the voltage division ratio of the resistors 20 and 25, so the voltage division ratio of these resistors 20 and 25 can be set appropriately. The time from when the oil level detection switch 24 closes until the terminal voltage of the capacitor 28 reaches the trigger level of the thyristor 30 is adjusted to an appropriate length, and the instantaneous closing of the oil level detection switch 24 causes the thyristor 30 to be activated. This can prevent the engine from misfiring due to conduction.

In the embodiment described above, when the engine misfires and is stopped due to a drop in the oil level, when the engine is restarted, the thyristor 30 does not conduct because the capacitor 28 is not charged at the time of restart. Therefore, the ignition device IG operates normally and the engine starts, but if the oil level detection switch 24 is closed and the engine rotates for a certain period of time, the terminal voltage of the capacitor 28 reaches a predetermined value and the thyristor 30 becomes conductive. The engine then stops again. In this way, when the engine stops due to a drop in the oil level, if you restart the engine, the engine will stop again after a short time, so you can know from this that the engine has stopped due to a drop in the oil level. Can be done.

In the above embodiment, the capacitor 34 is provided to protect the transistor 36.
Normally, the capacitance of this capacitor 34 is set to a small value, but if the capacitance of this capacitor 34 is set to a large value, it is possible to maintain the transistor 36 in a conductive state, and if this setting is made, the engine will not misfire. The lamp 38 can be turned on continuously when the vehicle is in use.

Figure 2 shows another embodiment of the present invention.
In this embodiment, a PNP transistor 44 is connected to the collector of the transistor 36 via a resistor 43.
A resistor 45 is connected between the emitter and base of the transistor 44. A lamp 38 serving as a light emitting display means is connected between the collector of the transistor 44 and the ground, and a diode 40 with an anode facing the ground side is connected in parallel to both ends of the lamp 38. The negative emitter of the transistor 44 is connected to the positive terminal of the battery 39, which is grounded.
When the transistor 44 is turned on, current is supplied from the battery 39 to the lamp 38 through the collector and emitter of the transistor 44.

In this embodiment, transistors 36 and 44 and resistors 35, 37, 43 and 45 constitute a transistor switch circuit 41.

When the circuit shown in FIG. 2 is used, when the thyristor 30 becomes conductive and a voltage appears across the resistor 31, the transistor 36 becomes conductive, and due to the conduction of the transistor 36, a base current flows to the transistor 44, and the transistor 36 becomes conductive. 44 becomes conductive. Therefore, current flows from the battery 39 to the lamp 38 through the collector-emitter of the transistor 44, and the lamp is lit. With this configuration, one end of the lamp 38 can be grounded.

The ignition device used in the above embodiment is merely an example, and the ignition device that can be used in the present invention is one whose power source is an ignition power coil installed in a generator driven by the engine. It is not limited to the circuit device shown in the above example. For example, in the example shown in Figure 1, the ignition power supply coil 1 is provided separately from the ignition coil, but this also applies if the ignition coil is housed in the generator and the primary coil of the ignition coil also serves as the ignition power supply coil. Can apply ideas. Further, the circuit that short-circuits the ignition power supply coil and interrupts the short-circuit current is not limited to the above example. For example, without using the signal coil 10, the voltage across the ignition power supply coil or the voltage across the transistor switch connected in parallel to the ignition power supply coil is detected, and when the voltage exceeds a predetermined value, the transistor switch is shut off. It is also possible to use a known circuit designed to do this. Furthermore, the present invention can also be applied when a capacitor discharge type ignition device is used.

[Effects of the invention] As described above, according to the invention, the transistor switch is triggered by the voltage across the current limiting element connected in series with the coil shorting thyristor to drive the light emitting display means. To obtain an oil level warning device for an internal combustion engine, which uses a battery as a power source and can drive a light emitting display means in synchronization with the operation of a coil shorting thyristor with a simple circuit configuration, and can provide a clear display with a simple structure. There is an advantage that it can be done. Furthermore, the light emitting display means is driven in synchronization with the operation of the coil short circuit thyristor, but the presence or absence of the light emitting display means is unrelated to the operation of the coil short circuit thyristor, so even if the light emitting display means malfunctions, the engine will stop. It has the advantage of being able to operate reliably.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of the present invention;
The figure is a circuit diagram showing the main parts of another embodiment of the present invention. 1...Ignition power supply coil, 3...Transistor,
5...Ignition coil, IG...Ignition system for internal combustion engine,
30...Thyristor for coil short circuit, 31...Resistor, 36, 44...Transistor, 38...Lamp, 39...Battery.

Claims (1)

[Claims for Utility Model Registration] An ignition power supply coil that generates an alternating current voltage in synchronization with the rotation of an internal combustion engine, an ignition device for an internal combustion engine that is driven by the output of the ignition power supply coil, and a lubricating oil level that is at a lower permissible limit. an oil level detection switch that performs a detection operation when the oil level falls below a value, a coil short circuit thyristor connected in parallel to the ignition power supply coil, and a trigger for the thyristor when the oil level detection switch performs a detection operation. and a trigger circuit for warning a low oil level by causing the thyristor to substantially short-circuit the ignition power supply coil and cause the engine to misfire when the oil level in the internal combustion engine falls below a permissible lower limit value. In the oil level warning device for use in an oil level warning device, a current limiting element is connected in series to the coil shorting thyristor, and a light emission is triggered by a voltage obtained across the current limiting element when the coil shorting thyristor is electrically conductive. An oil level warning device for an internal combustion engine, comprising: a transistor switch circuit for driving a display means; and a light emitting display means connected to a battery via the transistor switch circuit and lit when the transistor switch circuit is conductive.