JPS58150713A - Controlling device for interruption of fuel flow - Google Patents

Abstract

PURPOSE:To enlarge a voltage zone of electric power source and thereby achieving a year-around monitoring for a fuel system, by performing a highly precise voltage check free from influences of ambient temperature. CONSTITUTION:A main control section 6 comprises a microcomputer and is adapted to measure a flow rate of fuel per a unit timed period with a frequency as desired, with basis on a quantity of flow rate signals which are obtained by inputting the micro-computer a flow rate signal and a clock signal respectively given by a sensor input section 3 and by a clock generating section 2. The micro-computer stores beforehand data concerning a flow rate of fuel, such data being utilized for interrupting the fuel flow or any abnormality. The micro- combuter also encludes a repetitive timer adapted to actuate a voltage detecting section 7 periodically. By causing the voltage detecting section 7 to operate, a battery is checked for its voltage by inputting a signal from the voltage detecting section 7 thereto, while simultaneously indicating an alarming on a displaying section 4. Moreover, an electric power source voltage comparing circuit 10 adapted to compare a battery voltage with a criterion voltage can detect an exhausted battery.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel cutoff control device using a microcomputer powered by a battery.

Conventionally, there have not been many fuel cutoff control devices that use batteries as a power source. In addition, many common devices powered by batteries lose their original functionality when the battery voltage drops, as can be seen in devices that already have a display, such as watches and calculators. The user only becomes aware that the battery voltage has dropped when he or she becomes aware of abnormal conditions such as an increase in time error or the inability to perform calculations. In this way, there are many products that do not guarantee operation when the voltage drops.

The function of a fuel cutoff control device is to install it at the entrance of a gas supply line, such as the one found in each household, and automatically shut down the supply line when it is determined that there is an abnormality based on the flow rate, such as when gas is continuously flowing out. Such equipment must maintain monitoring operations throughout the year. In addition, this type of device is installed far away (outdoors), and daily users cannot frequently check the presence or absence of batteries when using fuel.
Furthermore, the installation environment is subject to conditions such as a wide temperature range. Therefore, it is necessary to detect battery voltage drop with high precision and to reliably notify this information.

The present invention aims to expand the power supply voltage range by performing a high-precision voltage check that is not dependent on the ambient temperature in a device with a battery voltage check function, thereby making it possible to monitor the device all year round. It is an object.

In order to achieve the above object, the present invention includes a reference voltage generation circuit, a determination voltage generation circuit that performs temperature correction on this generated voltage, a power supply voltage comparison circuit that compares the voltage of this generation circuit with the voltage of a battery power source. The basic configuration includes a main control that drives the reference voltage generation circuit, the determination voltage generation circuit, and the power supply voltage comparison circuit at predetermined intervals, and this configuration allows the battery voltage to be dependent on the ambient temperature. This is something that can be checked intermittently.

An embodiment of the present invention will be described below with reference to FIG.

In the figure, 1 is a power supply unit consisting of a battery, 2 is a clock generation unit that generates a clock that is a reference for time counting, and 3
Reference numeral 4 indicates a sensor input unit that inputs the fuel flow rate signal, 4 indicates a display unit consisting of a light emitting diode (LED)/liquid crystal that displays a plurality of different conditions, and displays abnormalities; 5 indicates a self-holding unit that shuts off the fuel supply path. A shutoff section consisting of a type solenoid valve, 6
7 is a main control unit consisting of a microcomputer, 7 is a reference voltage generation circuit 8 consisting of a diode, a judgment voltage generation circuit 9 having a temperature sensing element for correcting the voltage from the reference voltage generation circuit, and an output of the judgment voltage generation circuit. This is a voltage detection section consisting of a power supply voltage comparison circuit 1o having a voltage comparator that compares the voltage with the voltage of the power supply section 1.

Next, the operation of the above configuration will be explained.

First, when the power supply section 1 is turned on, the entire control device becomes operational. The main control unit 6 consists of a microcomputer,
The flow rate signal from the sensor human power section 3 and the clock signal from the clock generation section 2 are input, and the fuel flow rate per unit time is measured from the number of flow rate signals at arbitrary time intervals. The microcomputer has registered in advance flow rate data that serves as a reference for shutting off or displaying an alarm, and compares the measurement results with the flow rate data. The registered flow rate is, for example, data on the maximum passing acid that must not be exceeded under normal usage conditions as specified by the gas meter in each home in the gas supply line (this value must be exceeded when the gas valve is opened). There is a suspicion of a leak accident.

), or flow rate data that indicates that if the elapsed time at the same flow rate exceeds the time specified by that flow rate, it is determined that the appliance was forgotten to be turned off and is shut off. As a result of the comparison, if the measured flow rate and time exceed the above-mentioned data, display data is output to the display section 4, and a cut-off output is also performed to the cut-off section 6. It also has a repeat timer that counts the clock signal from the clock generator 2 and operates the voltage detector 7 periodically (for example, every 24 hours). A signal from section 7 is input to check the presence or absence of battery voltage, and at the same time an alarm is displayed on display section 4. The diode in the reference voltage generation circuit 8, which constitutes a part of the voltage detection section 7, has a relatively low voltage (approximately 0.6 to 0.0
．． TV). Therefore, battery voltage 1.6-2
It is possible to detect a voltage of about 1. Further, in order to correct the reference voltage having a negative temperature coefficient of the diode, a judgment voltage generating circuit 9 having a temperature sensing element having a positive temperature coefficient is used to correct the temperature of the reference voltage. It is possible to generate a determination voltage that is unaffected even if the temperature fluctuates over a wide range. Furthermore, battery consumption can be detected by the power supply voltage comparison circuit 10 that compares this determination voltage with the battery voltage. Therefore, the reference voltage for determining battery consumption can be set to a value close to the minimum operating voltage of other circuit sections, and the power supply voltage that can be used can be expanded.

FIG. 2 shows a specific example based on the diagram 74 of FIG. 1. The same numbers as in FIG. 1 indicate the same contents. Reference numeral 11 denotes a crystal oscillator whose frequency is divided by a counter 12 to generate, for example, a clock pulse with a period of 0.1 seconds to the input terminal of the main controller 6011. Reference numeral 21 is a mechanism for measuring the flow rate of fuel, and is installed close to a meter where a magnet moves back and forth depending on the gas flow rate, and a transistor 22 responds to the operation of the reed switch 21. Therefore, the main control unit 6 calculates the fuel flow rate per unit time at any given time based on the number of pulses that enter the input terminal of I2 and the time when the clock pulses that enter the input terminal of 11 are counted. 1, 13 to 16 are transistors that supply current to light emitting diodes (LEDs) 16, 17, and 18 connected to each other, and these are connected to the output terminal o of the main control unit 6.
1,02. o3. controlled by 19 is a transistor for driving the self-holding electromagnetic valve 2Q, and is a main control Ne.

Controlled by output terminal o4. Transistors 24 and 26 are connected to the 05 terminal of the main control section 6 and are periodically driven to supply power to the voltage detection section 7. A diode 26 generates a reference voltage VD. The judgment voltage generation circuit includes a voltage comparator 2θ, a temperature-sensitive resistance element 27 having a positive temperature coefficient, a resistor 28 connected in series with the temperature-sensitive resistance element, and a judgment voltage vs to a power supply voltage comparison circuit 1o. It consists of a capacitor 31 that supplies the voltage VD, which corrects the voltage VD that depends on the temperature change of the reference voltage generation circuit 8.
Generates a temperature-independent voltage vs.

The power supply voltage comparison circuit 1o includes a voltage comparator 31 that compares the judgment voltage Vs with the voltage at the connection point of the resistor 29.30 that supplies the power supply voltage, and is connected to the input terminal of the main control unit 6! . Outputs a signal indicating the battery voltage determination result to The voltage comparator 26 is configured such that E applied to the input terminal of the voltage comparator 26 of the judgment voltage generating circuit 9 is always equal to the reference voltage VD.
The output terminal connection point voltage vo of is controlled. For example, if VD changes from o, eV to 0.7V due to a decrease in ambient temperature, Vo will shift to the high side (resistance 28 is R1, temperature sensitive resistance element 27 is R2) V sX-'1- = 0.7V, vo is adjusted R1+R2, but at this time, the temperature sensitive resistance element 2 having a positive temperature coefficient
7 is under the same temperature condition as the diode 26, its resistance is lowered, and the determination voltage vs does not change.

In this way, the main control unit e can operate the voltage detection unit intermittently to reduce power consumption, and
Since the battery voltage can be checked without being dependent on low voltage and temperature, it is possible to set the value of the judgment voltage close to the minimum operating voltage of other circuit parts.
The operating voltage range can be expanded.

As described above, the fuel cutoff control device of the present invention provides the following effects. By adding a diode reference voltage generation circuit and a judgment voltage generation circuit with a temperature correction circuit to the voltage detection section that operates intermittently by the main control section with a timer function, it saves power and is independent of temperature. It becomes possible to check the battery voltage with high precision, making it possible to monitor the device all year round.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a fuel cutoff control device according to an embodiment of the present invention, and FIG. 2 is a specific circuit diagram of FIG. 1. 1...Power supply section, 3...Sensor power section, 6...Shutoff section, 6...Main control section, End...
... Voltage detection section, 8 ... Reference voltage generation circuit, 9 ... Judgment voltage generation circuit, 10 ...
Power supply voltage comparison circuit.

Claims (1)

[Scope of Claims] A power supply section consisting of a battery, a sensor power section inputting a fuel flow rate signal, a cutoff section cutting off a fuel supply path, a reference voltage generation circuit consisting of a diode, and a reference voltage generation circuit consisting of a diode, a voltage detection section comprising a judgment voltage generation circuit for temperature-compensating the voltage and a power supply voltage comparison circuit for comparing the output voltage of the judgment voltage generation circuit with the voltage of the power supply section; and a judgment standard for driving at least the cutoff section. a data storage section in which flow rate data is registered in advance; and the cutoff section. It has an output terminal for driving each of the voltage detecting sections, an input terminal for inputting signals from the sensor human power section and the voltage detecting section, and drives the voltage detecting sections at predetermined time intervals and receives signals from the voltage detecting section. A fuel cutoff control device comprising a main control section configured to determine an input signal.