JP2546292Y2 - Chemical liquid detection circuit in power atomizer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chemical liquid detection circuit which is attached to a chemical liquid sprayer driven by an internal combustion engine and electrically detects a decrease of a liquid chemical contained in a tank below a certain value. is there.

[0002]

2. Description of the Related Art A chemical sprayer driven by an internal combustion engine, that is, a power sprayer, operates a pump by the internal combustion engine to atomize and spray a chemical solution. As in the case of the above-mentioned equipment, operation in no-load condition not only causes early damage to the equipment, but also is extremely dangerous, so it is desirable to stop the operation as soon as no-load operation occurs. It is rare.

In order to satisfy this demand, a float switch or an electrode rod switch for detecting that the amount of the chemical in the tank has fallen below a certain value has conventionally been attached to the chemical tank of the power sprayer, and the detection from this switch has been performed. The driver is notified by a signal that the amount of the chemical solution has fallen below a certain value.

The above-mentioned conventional chemical liquid amount detecting device is a single device attached to a chemical liquid tank, and comprises a power supply portion, a detecting portion, and a display portion.
The driver looked at the display on the display unit of the chemical liquid amount detection device, stopped the power sprayer, and refilled the tank with the chemical liquid.

[0005]

However, the chemical liquid in the tank during the spraying operation of the chemical liquid is generally wavy, so that in many cases, chattering occurs on the display unit, and the display is not reliable. There is a problem that the properties are extremely low.

Further, since the chemical liquid amount detecting device is a completely independent device, it is difficult to use the output signal for operation control of the sprayer, and it is difficult to reduce the manufacturing cost of the sprayer. there were.

Therefore, the present invention has been devised to solve the above-mentioned problems in the prior art, and has as its technical object to constitute as a part of an ignition device of an internal combustion engine which is a driving source of a sprayer. Accordingly, it is an object of the present invention to facilitate operation control of an internal combustion engine based on a detection signal and to effectively reduce the manufacturing cost of a sprayer.

[0008]

Means of the present invention for solving the above-mentioned technical problem is that it is connected between both terminals of a primary winding of an ignition coil of an engine ignition device;
The connection between the two terminals of the primary winding is achieved through a rectifying diode, and the connection through the rectifying diode is performed by a capacitor for voltage stabilization and a chemical solution as an object to be detected. A series circuit of a first transistor connected to a base which is in a state of "closed" and a delay timer circuit for delaying the output of the first transistor for a predetermined time and outputting the same; One transistor is to be turned on when the sensor is electrically "open", and a second transistor is provided which is turned on by an output of the delay timer circuit and outputs an output signal to an output terminal.

Between the rectifying diode and the output terminal,
It is convenient to connect a series circuit of a resistor and a light emitting diode, and it is effective to use the output signal from the output terminal as a drive command signal for a stop circuit that forcibly stops the operation of the ignition circuit of the ignition device. It is more preferable to connect a resistor for adjusting the sensitivity between the collector and the base of the first transistor.

[0010]

When the sprayer is operating, that is, when the internal combustion engine is operating, part of the electric power induced in the primary winding of the ignition coil of the ignition device is supplied to the voltage stabilizing capacitor via the rectifying diode. And is applied as a substantially constant voltage to the first transistor.

When the amount of the chemical in the chemical tank is equal to or greater than a predetermined amount, the sensor, which is an electrode sensor attached to the tank, is electrically short-circuited by the chemical in the tank, that is, "closed". In this state, the base potential of the first transistor is grounded via this sensor, and is maintained in the turn-off state, so that the output signal from the liquid detection circuit according to the present invention is not output. .

On the contrary, when the sensor is completely separated from the chemical solution in the tank and is electrically opened, that is, in the “open” state, the base potential of the first transistor is established,
The first transistor turns on.

When the first transistor is turned on,
The power of the primary winding or the power charged in the voltage stabilizing capacitor is input to the delay timer circuit through the first transistor, and after a fixed time set by the delay timer circuit, the base of the second transistor is set. Output the trigger signal to

The second transistor is turned on by a trigger signal from the delay timer circuit, and outputs an output signal to the output terminal as a detection signal indicating that the amount of the chemical in the tank has decreased to a certain value or less.

Further, when the amount of the chemical in the tank is near a set constant value, a wavy of the chemical may cause a short-circuit of the sensor to be intermittently achieved by the chemical. If the time interval of the intermittent short circuit due to the sensor is shorter than the time set by the delay timer circuit, the first transistor is turned off before the trigger signal is output from the delay timer circuit to the second transistor. No output signal is output. Conversely, if the time interval of the intermittent short circuit of the sensor due to the chemical is longer than the time set by the delay timer circuit, the trigger signal is sent from the delay timer circuit to the second transistor before the first transistor is turned off. Is output, an output signal is output as a detection signal.

Therefore, by appropriately setting the delay time of the delay timer circuit in accordance with the use conditions of the sprayer, that is, the degree of undulation of the chemical solution in the tank when the sprayer is used, the undulation of the chemical solution is affected. Without being done
It accurately and reliably detects that the chemical solution has decreased below a set fixed value.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. The ignition device to which the liquid detection circuit 1 according to the present invention is attached includes an ignition circuit 18 connected between both terminals of a primary winding 20 of an ignition coil 19 having a plug 22 connected to a secondary winding 21.
And the stop circuit 23 are connected in parallel.

The liquid detecting circuit 1 attached to the ignition device is provided between the cathode of the rectifying diode 2 connected to the positive terminal A of the primary winding 20 and the negative terminal B of the primary winding 20. A capacitor 3 for voltage stabilization is inserted and connected, and a series circuit of a first transistor 5 having a sensor 14 connected to a base and a delay timer circuit 7 is inserted and connected, and a base is connected to an output terminal of the delay timer circuit 7. The output terminal C and the terminal B
And is connected between them.

The first transistor 5 has its collector
A sensing circuit 4 is formed by connecting a resistor 6 for setting the sensitivity between the bases. The other end of the sensor 14 attached to a chemical tank (not shown) is connected to a terminal B.

The sensing circuit 4 sets the sensitivity of the liquid detecting circuit 1 and corresponds to the resistance value of the sensitivity setting resistor 6 corresponding to the resistance value of the sensor 14 which has been brought into the "closed" state by the chemical. Setting the liquid detection circuit 1
Set the sensitivity of.

The delay timer circuit 7 forms a discharge circuit, which is connected between the emitter of the first transistor 5 and the terminal B and includes a series circuit of a resistor 9 for setting a charging voltage and a charging capacitor 8. A parallel circuit with the resistor 10, a diode 11 connected in parallel with the resistor 9 to form a discharging circuit of the charging capacitor 8, and a cathode connected to the positive electrode of the charging capacitor 8 and an anode connected to the output of the delay timer circuit. Zener diode 13 in reverse orientation as terminal
And is composed of

In the delay operation of the delay timer circuit 7, the charging speed of the charging capacitor 8 is set by the resistance value ratio of the resistor 9 and the resistor 10, and the potential of the positive electrode of the charging capacitor 8 is The time required to reach the breakdown voltage is defined as the delay time.

When the "open" state time of the sensor 14 due to the chemical is shorter than the delay time set by the delay timer circuit 7, the charging transistor 8 is charged by turning on the first transistor 5. While the first transistor 5 is turned off, the power is discharged through the path of the charging capacitor 8 → the discharging diode 11 → the resistor 10 → the charging capacitor 8 and waits for the next charging operation.

The actual setting of the delay time in the delay timer circuit 7 is set by adjusting the resistor 10 as a fixed resistor and adjusting the resistor 9 and the charging capacitor 8.

The second transistor 13 which inputs the output signal of the delay timer circuit 7 to the base as a trigger signal,
The emitter is connected to the terminal B, and the collector is connected to the terminal C to which the input terminal of the stop circuit 23 is connected via the diode 17 for preventing backflow.

Therefore, when the second transistor 13 is triggered by the output of the delay timer circuit 7, that is, when the amount of the chemical in the tank becomes equal to or less than a predetermined value, the sensing circuit 4
Output a signal from the liquid detection circuit 1 to the stop circuit 23 from the terminal C to activate the stop circuit 23, and to output the output signal from the terminal C to both terminals of the primary winding 20. Since A and B are short-circuited, the ignition circuit 1
8 stops its operation and the internal combustion engine stops.

When the internal combustion engine stops, the supply of electric power from the ignition device to the liquid detection circuit 1 stops, so that the liquid detection circuit 1 stops its operation and charges the voltage stabilizing capacitor 3 and the charging capacitor 8. Since the power is discharged and the output signal from the terminal C disappears, the stop circuit 2
3 is in a stopped state. Therefore, by refilling the tank with the chemical solution, the internal combustion engine can be restarted.

The series circuit of the resistor 15 and the photodiode 16 inserted between the cathode of the rectifying diode 2 and the cathode of the backflow preventing diode 17 is formed by turning on the second transistor 13. It operates and constitutes a display function part for notifying the driver that the liquid detection circuit 1 has output the output signal by the light emission of the photodiode 16, and the driver can stop the internal combustion engine by seeing this display. Can be recognized.

[0029]

[Effects of the Invention] Since the present invention has the above-described configuration, the following effects can be obtained. Since the liquid detection circuit is configured as a part of the ignition device of the internal combustion engine, an output signal which is a detection signal of the liquid detection circuit can be used as it is as a command signal for the ignition device. Control becomes easy, and the operation of the power sprayer can be performed more safely.

If the output signal of the first transistor is not output by the delay timer circuit for a certain period of time or longer, the output signal of the liquid detection circuit is not output. It is possible to obtain a stable and highly reliable detection signal without chattering.

Since the liquid detection circuit is configured as a part of the ignition device of the internal combustion engine, it does not require a dedicated power supply unit.
Therefore, the whole can be manufactured at low cost.

The sensing circuit is formed by connecting a resistor between the collector and the base of the first transistor. By adjusting the resistance of the resistor, the trigger level of the first transistor with respect to the resistance of the sensor is adjusted. The detection sensitivity can be set freely, and thus the detection sensitivity setting level for each type of chemical solution can be easily and freely set, and a highly accurate detection operation can be obtained.

[Brief description of the drawings]

FIG. 1 is an electric circuit diagram showing a circuit configuration of an embodiment of the present invention connected to an ignition device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1; Liquid detection circuit 2; Rectifier diode 3; Voltage stabilizing capacitor 4; Sensing circuit 5; First transistor 6; Setting resistor 7; Delay timer circuit 8; Charging capacitor 9; Setting resistor 10; Resistance 11; Discharge diode 12; Zener diode 13; Second transistor 14; Sensor 15; Limiting resistor 16; Photodiode 17; Backflow prevention diode 18; Ignition circuit 19; Ignition coil 20; Primary winding 21; Winding 22; Plug 23; Stop circuit A, B, C;
Terminal

Claims (4)

(57) [Scope of request for utility model registration] A rectifying diode is provided between both terminals (A) and (B) of a primary winding (20) of an ignition coil (19) of an engine ignition device.
Through (2), a capacitor (3) for voltage stabilization and a sensor (1
4) a series connection of a first transistor (5) connected to the base and a series circuit of a delay timer circuit (7) for outputting the output of the first transistor (5) with a delay for a predetermined time, The first transistor (5) is turned on by the electrical "open" of the sensor (14), and is turned on by the output of the delay timer circuit (7) and the output terminal (C).
A chemical liquid detection circuit in a power sprayer, comprising a second transistor (13) for outputting an output signal to the power sprayer. 2. A rectifying diode (2) and an output terminal (C).
The chemical liquid detection circuit in the power sprayer according to claim 1, wherein a series circuit of a resistor (15) and a light emitting diode (16) is connected between them. 3. A stop circuit for forcibly stopping the operation of an ignition circuit (18) of an ignition device based on an output signal from an output terminal (C).
The chemical liquid detection circuit in the power sprayer according to claim 1 or 2, wherein the driving command signal is the drive command signal of (23). 4. A chemical liquid detection circuit in a power sprayer according to claim 1, wherein a resistance adjusting resistor is connected between the collector and the base of the first transistor.