JPH0720381Y2 - Internal combustion engine stop device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to an internal combustion engine stop device for stopping an engine by an external signal.

[Conventional technology]

FIG. 2 shows a conventional device, 1 is a generator coil of a magnet generator, 2 is a diode for rectifying the output of the generator coil 3,
Is a capacitor, 4 is an ignition coil, 5 is an ignition plug, 6 is a thyristor, 7 to 9 are diodes, 10 is a capacitor, 11
Is a zener diode, 12 is a constant voltage source, 13 is an oil level switch for detecting the oil level of the engine, 14 is a transistor, 15 and 16 are resistors, and 17 is a thyristor.

Next, the operation of the above conventional device will be described. The output of the magneto coil 1 is rectified by the diode 2 and charged in the capacitor 3. On the other hand, when a signal is generated in a signal coil (not shown), this signal is applied to the gate of the thyristor 6, the thyristor 6 becomes conductive, the charge of the capacitor 3 is discharged through the primary side of the ignition coil 4, and the charge of the ignition coil 4 is discharged. High voltage is generated on the secondary side. As a result, the spark plug 5 discharges and ignites the engine. The output of the power generation coil 1 is rectified by the diodes 8 and 9, smoothed by the capacitor 10, and made constant by the zener diode 11 to form a constant voltage source 12.

The oil level switch 13 is normally open and the transistor 14 is turned on and the gate of the thyristor 17 is grounded to turn it off. Therefore, the engine is ignited normally. However, when the oil level of the engine decreases, the switch 13 closes, the transistor 14 turns off, the thyristor 17 turns on, the output of the magneto coil 1 is short-circuited by the thyristor 17, ignition is not performed, and the engine stops. To do.

[Problems to be solved by the invention]

However, in the above-mentioned conventional device, the oil level switch 13 is installed in the oil flow path of the engine,
Alternatively, if the oil pressure is detected, it is determined that the oil has decreased when the engine is stopped, but the oil cannot be started even though the engine is normal. There was a problem.

The present invention has been made in order to solve the above problems, and an object thereof is to obtain an engine stop device capable of preventing the engine stop at the time of starting due to a malfunction of the oil level switch.

[Means for solving problems]

The internal-combustion-engine stop apparatus according to the present invention is provided with conduction preventing means for preventing conduction of the switching element that short-circuits the output of the power generation coil for a predetermined time after the power generation of the power generation coil is started.

[Action]

In this invention, the conduction preventing means prevents conduction of the switching means for a predetermined time after the engine is started. At this time, even if the oil level switch operates, the switching element does not conduct and the output of the generator coil is not short-circuited.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings. First
In the figure, 18 is a transistor, 19 is a comparator as a comparison means, 20 to 23 are resistors, and 24 is a capacitor. Other configurations are the same as the conventional one. The resistor 21 and the capacitor 24 constitute an integrating means.

In the above configuration, the spark plug 5 is ignited based on the output of the power generation coil 1, and the engine ignition is stopped by turning on the oil level switch 13 to stop the engine. On the other hand, a voltage obtained by dividing the voltage of the constant voltage source 12 by the resistors 22 and 23 is applied to the (+) terminal of the comparator 19, and a voltage obtained by dividing the voltage of the constant voltage source 12 by the resistor 21 and the capacitor 24 is applied to the (−) terminal. This voltage is the resistance of resistor 21 and capacitor 24.
Rises with a predetermined time constant determined by the electrostatic capacitance of. Therefore, the voltage at the (+) terminal, which is a predetermined value, exceeds the voltage at the (-) terminal for a predetermined time after the engine is started, and the output of the comparator 19 is turned on to the transistor 18 at a high level. Therefore, the gate voltage of the thyristor 17 becomes zero, and even if the oil level switch 13 is turned on, the thyristor 17
Is never turned on and the engine is ignited normally. After a lapse of a predetermined time after starting, the output of the comparator 19 becomes low level, and the transistor 18 is turned off. Therefore, when the oil level switch 13 is turned on, the thyristor 17 is also turned on, the ignition is stopped, and the engine is stopped.

[Effect of device]

As described above, according to the present invention, the switching means for short-circuiting the output of the generator coil is not conducted for a predetermined time after the engine is started, so that the output of the generator coil is not short-circuited even if the oil level switch malfunctions. The engine is ignited normally, and a normal start can be performed. Further, according to the present invention, since the conduction preventing means operates based on the power generation output of the generator coil, it is possible to reliably detect the start of the engine and prevent conduction of the switching element for a predetermined time after the engine starts.

[Brief description of drawings]

FIG. 1 is a circuit diagram of this device, and FIG. 2 is a circuit diagram of a conventional device. 1 ... Generator coil, 3 ... Capacitor, 4 ... Ignition coil, 6,17 ... Thyristor, 13 ... Oil level switch, 18 ... Transistor, 19 ... Comparator. The same reference numerals in the drawings indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. An ignition circuit for controlling energization from a power generating coil to an ignition coil, a switching element for short-circuiting the output of the power generating coil by making it conductive, an oil level of an internal combustion engine being detected, and the oil level reaching a predetermined value. In an internal combustion engine stop device equipped with an oil level switch that operates when not in operation to conduct the switching element, an integrating means that starts integration at a predetermined time constant based on the power generated from the generator coil, and the integrating means. Comparing means for comparing the output of the power generator with a predetermined value, and conduction preventing means for preventing conduction of the switching element for a predetermined time after the start of power generation of the magneto coil based on the output of the comparing means. A characteristic internal combustion engine stop device.