JP2001171366A - Vehicular fuel gauge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicular fuel gauge capable of accurately detecting fuel quantity inside a fuel tank without being affected by contact resistance of a moving contact caused by a sulfide substance or the like inside gasoline. SOLUTION: This device is provided with first and second resistance type sensors 1 and 2 having moving contacts S1 and S2 arranged in different positions inside the fuel tank of a vehicle. First and second fixed resistors R 1 and R2 are connected between each both ends of resistors VR1 and VR2 of the first and second resistance type sensors 1 and 2 and the moving contacts S1 and S2 are connected between positive and negative of a power source BA. An output part 3 detects a ratio of amperages passing the first and second fixed resistors R1 and R2 by energization from the power source BA for detecting a liquid level detected by the first and second resistance type sensors 1 and 2. The output part 3 comprises differential amplifiers AP1 and AP2 detecting descent voltages of the fixed resistors R1 and R2 and an arithmetic part CP determining a ratio V1/V2 of output voltages V1 and V2 thereof, and it can drive a moving magnet type gauge or the like on the basis of this ratio data for indicating remaining fuel quantity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel gauge for a vehicle equipped with a fuel tank.

[0002]

2. Description of the Related Art A vehicle running on fuel such as gasoline or methanol is equipped with a fuel tank for storing fuel, and an engine is driven by supplying fuel from the fuel tank. The fuel gauge to be installed is installed on the dashboard in front of the driver's seat, and the driver checks this to determine that fuel is insufficient and refuel.

[0003] As such a fuel gauge for indicating the remaining amount of fuel in the fuel tank, there are a cross-coil meter, a stepping motor meter, which indicates with a pointer, a liquid crystal display, which indicates with a bar graph or a digital value. A liquid level sensor in which a resistance type sensor having a simple structure and an inexpensive structure is installed in a fuel tank is generally known as a device that uses a fluorescent display tube or the like and detects the remaining fuel amount in the tank. The driver can always check the fuel level indicated by the fuel gauge at the driver's seat during driving, and can judge the necessity of refueling according to the distance to the destination.

[0004]

However, detection of the remaining amount of fuel by a fuel gauge comprising such a resistance type sensor involves rotating the movable contact at an angle by means of an arm connected to a float floating according to the liquid level, thereby making it possible to connect the resistor to the resistor. Although the resistance value corresponding to the liquid level is determined by the voltage at the connection position with many connected electrodes, the contact position changes when immersed in fuel such as gasoline or methanol, As long as the contact portion is energized, problems such as contact wear and contact failure may occur in the contact portion, but this has been improved by improving the contact material. However, in the case of particularly poor fuel such as gasoline, Ag
The (silver) component is sulfided and the silver sulfide deposits on the contact surface, increasing the electrical resistance between the contacts and affecting the current flowing between the contacts, grounding the movable contact or outputting this movable contact. In a detection method using a partial voltage specification such as that used in a terminal such as Japanese Utility Model Publication No. 60-23709, the actual partial pressure by the movable contact of the variable resistor can be obtained due to the resistance between the contacts due to the sulfide. However, there is a problem that an error occurs in the indication of the fuel amount as a fuel gauge.

Accordingly, the present invention provides a fuel gauge for a vehicle which detects a fuel amount with higher accuracy without using an expensive contact portion or a conductor electrode which is resistant to deterioration and corrosion such as sulfuration or by using such a contact portion. Is provided.
In particular, in order to detect the average liquid level in one tank in consideration of the liquid level inclination caused by the inclination of the vehicle, the actual liquid level is determined as follows.
No. 19, two liquid level sensors are arranged in a tank to obtain an average of the two liquid level sensors.
No. 8,830, the average output of two liquid level sensors provided in each of the separation chambers (main tank and sub tank or reservoir tank) in a tank composed of two chambers connected by a communication pipe. An object of the present invention is to provide a fuel gauge for determining the total remaining fuel amount, which is not affected by the contact resistance due to the sulfuration or the like in each liquid level sensor.

[0006]

According to the present invention, a fuel gauge for a vehicle is provided in a fuel tank of a vehicle, and receives a detection signal from a liquid level sensor for detecting a fuel amount in the tank, and displays the fuel amount. A fuel gauge, wherein the liquid level sensor comprises first and second resistive sensors having movable contacts arranged at different positions in a tank, and a resistance element of the first and second resistive sensors. The first and second detection elements are connected between both ends of the power supply, and the movable contact can be connected between the positive and negative sides of a power supply, and the amount of current flowing to the first and second detection elements by energization from the power supply And an output unit for detecting the liquid level detected by the first and second resistive sensors.

Further, the first and second detection elements are constituted by first and second fixed resistors, and the output section is generated by an amount of current to the first and second fixed resistors. A detection circuit for detecting a voltage drop is provided, and a ratio of the current amount is obtained by dividing a value of a voltage drop of the first and second fixed resistors.

[0008] Further, the output section includes a display section for displaying a fuel amount detected by the liquid level sensor based on an output signal corresponding to the current amount ratio.

The resistance values of the resistors of the first and second resistive sensors are the same, and the resistance values of the first and second fixed resistors are the same.

Further, the first and second detecting elements are
The output unit is constituted by first and second magnetic coils whose generated magnetic fields intersect, and the output unit is energized by a crossed magnetic field generated in accordance with the amount of current flowing through the first and second magnetic coils. The apparatus includes a rotating magnet and a pointer connected to the rotating magnet for indicating a fuel amount detected by the liquid level sensor.

The present invention is also a fuel gauge which is installed in a fuel tank of a vehicle and displays a fuel quantity upon receiving a detection signal from a liquid level sensor for detecting a fuel quantity in the tank.
The liquid level sensor includes first and second resistive sensors having movable contacts arranged at different positions in the tank, and connects one end of a resistor of the first and second resistive sensors. A first fixed resistor is connected between the other ends, and the movable contacts of the first and second resistive sensors are configured to be connectable between positive and negative of the power supply. A second fixed resistor is connected between the first and second resistive sensors by detecting a ratio of the amount of current flowing through the first and second fixed resistors by energization from the power supply. And an output unit for detecting the liquid level detected by the above.

The output section corresponds to a magnitude of a current amount detected by the first fixed resistor with respect to a detection value corresponding to a magnitude of a current amount detected by the second fixed resistor. The detection value difference is obtained, and the ratio of the detection value detected by the first fixed resistor to the detection value difference is obtained.

The present invention is also a fuel gauge installed in a fuel tank of a vehicle and receiving a detection signal from a liquid level sensor for detecting a fuel amount in the tank, and displaying the fuel amount.
The liquid level sensor is formed of a resistance sensor having a movable contact, and connects first and second detection elements between both ends of a resistor of the resistance sensor and one of positive and negative of a power supply. A contact is connected to the other of the positive and negative sides of the power supply, and the ratio of the amount of current flowing to the first and second detection elements by the energization from the power supply is detected and detected by the first and second resistance sensors. And an output unit for detecting a liquid level.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A first resistive sensor 1 and a second resistive sensor 2 having movable contacts S1 and S2 arranged at different positions in a fuel tank of a vehicle are provided. Resistors VR1 of the two resistive sensors 1 and 2
A first fixed resistor R1 and a second fixed resistor R2 are connected between both ends of VR2 and the movable contact S
1, S2 are connected between the positive and negative sides of the power supply BA, and the first and second fixed resistors R1,
The output unit 3 detects the ratio of the amount of current flowing through R2 and detects the liquid level detected by the first and second resistance sensors 1 and 2, so that the contacts S1 and S2
Even if the contact resistance between the conductor electrodes of the resistor VR1 and the resistor VR2 increases due to the influence of sulfuration, etc., the current ratio flowing through the first and second fixed resistors R1 and R2 is not affected, and the detection is performed with high accuracy. Becomes possible.

The resistors VR1 and VR2 of the first and second resistive sensors 1 and 2 have the same resistance value, and the first and second fixed resistors R1 and R2 have the same resistance.
, The design when setting the current ratio is facilitated.

The first and second fixed resistors R
1 and R2 instead of first and second magnetic coils L1 and L2 that generate a cross magnetic field, and the output unit 3 is configured to correspond to the amount of current flowing through the first and second magnetic coils L1 and L2. By including a rotating magnet MG that is energized by the generated crossing magnetic field and a pointer PO connected to the rotating magnet MG and indicating the fuel amount detected by the liquid level sensor, the resistance between the contacts is similarly reduced. Detection that is not affected can be performed.

[0017]

FIG. 1 is a circuit diagram showing one embodiment of the present invention, in which a first resistive sensor 1 and a second resistive sensor as liquid level sensors are provided at different positions in a vehicle fuel tank. 2 are provided, and these resistance type sensors 1 and 2 are provided.
Numeral 2 has movable contacts S1 and S2 which rotate in connection with a float arm floating on the liquid surface in the fuel tank. Resistors VR1 and VR2 formed by printing a resistive material so as to have the same resistance value are provided.
1 and S2 are configured to slide on the conductor electrodes. The movable contact S1, of each resistance type sensor 1, 2,
S2 is connected to the positive and negative of the vehicle-mounted power supply BA, respectively,
First and second fixed resistors R1 and R2 (detection elements) having the same resistance value are connected between both ends of the first and second resistors VR1 and VR2.

Differential amplifiers AP1 and AP2 connected to both ends of the fixed resistors R1 and R2 and detecting the amount of current flowing through each of the resistors R1 and R2 based on a voltage drop between both ends.
And output voltages V1 and V1 of these differential amplifiers AP1 and AP2.
The output unit 3 is constituted by a calculation unit CP that detects V2 and obtains the ratio. The arithmetic unit CP can be constituted by a microcomputer, and A / D-converts the output voltages V1 and V2, and calculates a ratio of the digital values by division such as V1 / V2. The calculated ratio V1 / V2 is a ratio of the amount of current flowing through the fixed resistors R1 and R2, and the remaining fuel amount in the fuel tank is obtained. Therefore, based on the calculated data, for example, a liquid crystal display is used. If the digital display or the bar graph display is performed, the remaining fuel amount can be correctly grasped. That is, the detection liquid level of each of the resistance sensors 1 and 2 is determined by the position of each of the movable contacts S1 and S2. Since it is proportional to the resistance ratio divided by S1 and S2, the liquid level is obtained as the average value of each resistance sensor 1 and 2,
Thus, the remaining fuel amount can be obtained.

In the fuel meter shown in FIG. 2, the first and second detecting elements are constituted by first and second magnetic coils L1 and L2 for generating a cross magnetic field, and the output section 3 is provided by the magnetic coil L1. , L2, a rotary magnet MG controlled in rotation by a combined magnetic field and a pointer PO connected to the rotary shaft thereof, and provided with a scale plate and a magnetic instrument such as a so-called cross-coil instrument. To indicate the remaining fuel amount. In this case, the ratio of the amount of current flowing through the magnetic coils L1 and L2 is generated as the vector direction of the composite magnetic field, and the liquid level can be detected by the instruction of the pointer PO by the rotation of the rotating magnet MG in the magnetic vector direction.

The embodiment shown in FIG. 3 basically has the same operating principle as the embodiment shown in FIG. 1, except that the lead lines from the resistance type sensors 1 and 2 to the instrument panel in the vehicle are connected to each sensor 1. , 2 are required to be two, and four are required. Therefore, the number is reduced to three to simplify the wiring. That is, one ends of the resistors VR1 and VR2 of the first and second resistive sensors 1 and 2 are connected via the adjustment fixed resistor R0, and the first fixed resistor R3 is connected between the other ends. And the movable contacts S1 and S2 of the first and second resistive sensors 1 and 2 are connected between the positive and negative sides of the power supply BA, and a second fixed resistor R4 is connected between one movable contact S1 and the power supply BA. Connected. In this case, the adjustment fixed resistor R0 can be formed on the ceramic substrate of the first resistive sensor 1 or the second resistive sensor 2 at the same time when the resistor VR1 or VR2 is printed. May be mounted and connected on the substrate pattern.

As in the embodiment shown in FIG. 1, the output section 3 reduces the amount of current flowing through the first and second fixed resistors R3 and R4 by applying a current from the power supply BA to a voltage drop. The operating amplifiers AP1 and AP2 to be obtained and the operation unit CP which inputs the output voltage and obtains the ratio can be constituted. However, in this case, the current flowing through the fixed resistor R4 is connected to the power supply lines flowing through all the circuits of the resistors VR1 and VR2 and the adjusting resistor R0 and the fixed resistor R3. Movable contact S1,
To determine the ratio of the resistance divided at S2, the resistor R4
The ratio between the current flowing through the resistor R3 and the difference between the current values obtained by subtracting the current flowing through the resistor R3 may be obtained. Assuming that the voltage drop is V4, V3 / (V4-V3)
By such calculation, the resistance ratio divided by the movable contact of each of the resistance type sensors 1 and 2, that is, the liquid level can be correctly detected as in the embodiment of FIG. Here, the fixed resistors R0 and R3 have the same resistance value, and the resistors VR1 and VR2 and the fixed resistor R of the embodiment shown in FIG.
1 and R2, and as a result, the movable contact S
This is equivalent to detection based on the ratio of the amount of current to the circuit divided in S1 and S2.

According to the above configuration, as shown in the drawing, the fixed resistor as a detection element mounted in the indicator installed in the vehicle cabin from the resistance type sensors 1 and 2 installed in the fuel tank. Only three wirings are required from R1, R2, R3, R4 and the output unit 3 as compared with the four wirings in the embodiment of FIG. 1, so that the complexity of the wiring can be reduced.
In addition, long wires required for connection can be reduced.
The adjustment fixed resistor R0 has the same resistance value as the current-carrying circuit of the fixed resistor R3 as a detection element to facilitate detection. However, it is particularly necessary if the current ratio can be calculated. Instead, the resistance value of one of the conduction circuits VR1 and VR2 divided by the movable contacts S1 and S2 is set to VR1.
L and VR2L, and the other resistance values are VR1R and VR2R, the current ratio is (VR1L + VR2L) and (VR1R +
(VR2R + R3), the ratio may be calculated according to this ratio.

The embodiment shown in FIG. 4 does not use two resistive sensors as described above, but describes a fuel gauge with a single resistive sensor. That is, first and second fixed resistors R1 and R2, which are first and second detection elements, are provided between both ends of the resistor VR1 of the resistive sensor 1 grounded in the tank and the positive side of the power supply BA. And the movable contact S1 is connected to the negative side of the power supply BA, and the ratio of the amount of current flowing through the first and second resistors R1 and R2 due to energization from the power supply BA is detected to detect the first current. And an output unit 3 for detecting a liquid level detected by the second resistance sensors 1 and 2.

The output unit 3 has an operation unit such as a microcomputer, and outputs the fixed resistors R1 and R1 from the power supply BA.
2. By energization through the resistor VR1 and the movable contact S1,
A current amount corresponding to the resistance ratio divided by the contact position of the movable contact S1 corresponding to the liquid level flows through each of the fixed resistors R1 and R2, and the drop voltages V1 and V2 of the fixed resistors R1 and R2 are reduced. By measuring and determining the ratio V1 / V2, the ratio of the amount of current flowing through each fixed resistor R1, R2 can be determined. Also in this case, the fixed resistors R1, R2
A / D conversion may be performed to calculate a digital value by converting the voltage drops V1 and V2 of the movable contact S1 or the contact resistance value of the movable contact S1 or the conductor electrode surface of the resistive sensor 1 due to sulfuration or the floating of the ground potential of the movable contact S1 ( For example, accurate measurement can be performed without being affected by the voltage drop due to contact resistance due to grounding to the vehicle body) or fluctuations in the power supply voltage. Based on the calculated output data, the fuel amount can be displayed on the electronic display. Digital or bar graph display, or a pointer-driven instrument such as a movable magnet instrument or a stepping motor instrument.

In the detection of the amount of current in FIG. 4, the voltage at the lower ends of the fixed resistors R1 and R2 connected from the power supply BA is measured by the output unit 3, but as shown in FIG. The voltage at both ends may be detected by a differential amplifier, and the configuration of the resistance type sensors 1 and 2 has been described as a configuration in which the movable contact slides on the conductor electrode. The sensor may be configured to slide in the direction of the arrow. That is, the contact resistance of the movable contact is similarly involved in both of the energized circuits divided by the movable contact, but the ratio of the amount of current to each energized circuit is merely the change in the overall current, and the resistance value of that circuit is merely , Accurate detection is possible in all the embodiments.

[0026]

The fuel meter according to the present invention drives a movable contact of a variable resistance sensor by a float provided in a fuel tank of a vehicle and moving up and down according to a liquid level, and is divided by the movable contact. It detects the remaining fuel amount from the liquid level by detecting the resistance value ratio of the resistor, and energizes through the resistor and the movable contact of the resistive sensor, and determines the amount of current flowing through each divided resistor. The current is detected by a detection element connected to the current-carrying path to be divided, and the current is measured by calculating the ratio of the current amount.Since each divided resistor circuit has a bridge configuration, the movable contact or the resistor It can be detected as an accurate resistance ratio that is not affected by an increase in the contact resistance value due to sulfuration on the conductor electrode surface.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of a vehicular fuel gauge according to the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the vehicular fuel gauge according to the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the vehicular fuel gauge according to the present invention.

FIG. 4 is a circuit diagram illustrating a vehicle fuel gauge according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st resistance type sensor 2 2nd resistance type sensor 3 Output part BA power supply VR1 1st resistor VR2 2nd resistor S1 1st movable contact S2 2nd movable contact R1, R3 1st detection First fixed resistors R2 and R4 serving as elements Second fixed resistor R0 serving as a second detection element Fixed resistors for adjustment AP1 and AP2 Differential amplifiers forming output section 3 CP forming output section 3 Arithmetic unit L1 First magnetic coil serving as first detecting element L2 Second magnetic coil serving as second detecting element MG Rotating magnet configuring output unit 3 PO Indicator configuring output unit 3

Claims (8)

[Claims] 1. A fuel gauge installed in a fuel tank of a vehicle for displaying a fuel amount in response to a detection signal from a liquid level sensor for detecting a fuel amount in the tank. A first and a second resistive sensor having movable contacts disposed at different positions within the first and second resistive sensors. Connect the element and connect the movable contact between the positive and negative of the power supply, detect the ratio of the amount of current flowing to the first and second detection elements by energization from the power supply, the first and second A fuel gauge for a vehicle, comprising: an output unit for detecting a liquid level detected by a resistance sensor. 2. The method according to claim 1, wherein the first and second detection elements are constituted by first and second fixed resistors, and the output section is generated by a current amount to the first and second fixed resistors. 2. A detection circuit for detecting a voltage drop, wherein a ratio of the current amount is obtained by dividing a value of a voltage drop of the first and second fixed resistors.
Vehicle fuel gauge according to claim 1. 3. The output unit according to claim 2, wherein the output unit includes a display unit that displays a fuel amount detected by the liquid level sensor based on an output signal corresponding to the current amount ratio. Vehicle fuel gauge. 4. The resistance value of the resistor of the first and second resistive sensors is the same, and the resistance value of the first and second fixed resistors is the same. Item 3. A fuel gauge for a vehicle according to item 2. 5. The first and second detection elements are constituted by first and second magnetic coils whose generated magnetic fields intersect, and the output unit is connected to the first and second magnetic coils. 2. A rotating magnet which is energized by a cross magnetic field generated in accordance with an amount of flowing current, and a pointer connected to the rotating magnet for indicating a fuel amount detected by the liquid level sensor. The fuel gauge for a vehicle as described in the above. 6. A fuel gauge installed in a fuel tank of a vehicle and receiving a detection signal from a liquid level sensor for detecting a fuel amount in the tank, and displaying the fuel amount, wherein the liquid level sensor comprises a tank. The first and second resistive sensors each have a movable contact disposed at a different position in the first and second resistive sensors. One fixed resistor is connected, and the movable contacts of the first and second resistive sensors are configured to be connectable between the positive and negative sides of the power supply, and the second fixed contact is provided between one of the movable contacts and the power supply. A resistor is connected, and the liquid level detected by the first and second resistance sensors by detecting the ratio of the amount of current flowing through the first and second fixed resistors due to energization from the power supply. Vehicle equipped with an output unit for detecting Dual use fuel gauge. 7. The output unit according to claim 1, wherein the output unit is configured to correspond to a magnitude of the current detected by the first fixed resistor with respect to a detection value corresponding to a magnitude of the current detected by the second fixed resistor. A difference between the detected values to be detected, and a ratio of the detected value detected by the first fixed resistor to the difference between the detected values. 8. A fuel gauge which is installed in a fuel tank of a vehicle and displays a fuel amount by receiving a detection signal from a liquid level sensor for detecting a fuel amount in the tank, wherein the liquid level sensor is movable. Consisting of a resistive sensor having contacts, connecting the first and second detection elements between both ends of the resistor of the resistive sensor and one of the positive and negative of the power supply,
The movable contact is connected to the other of the positive and negative power supplies, and the ratio of the amount of current flowing to the first and second detection elements due to energization from the power supply is detected and detected by the first and second resistive sensors. A fuel gauge for a vehicle, comprising: an output unit for detecting a liquid level to be measured.