JPH04350520A - Liquid amount indicating instrument for vehicle - Google Patents

Abstract

PURPOSE:To prevent an amount of liquid which is indicated by a display means from being different from a warning period of a warning means. CONSTITUTION:Both an needle 19 which indicates an amount of remaining fuel in a fuel tank 8 and a warning lamp 5 which warms that the amount of remaining fuel in the fuel tank 8 is equal to or less than a specified amount control an indication position of the needle 19 and a lighting timing of the warning lamp 5 based on a voltage value as a liquid-surface level signal which is output from a sender unit 2 for detecting a liquid-surface level within the fuel tank 8.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid level indicator for a vehicle, such as a vehicle fuel gauge or a vehicle oil level gauge.

0002

2. Description of the Related Art Conventionally, a fuel meter 100 for an automobile as shown in FIG. and a receiver unit 105 having a pointer 104 that indicates the remaining amount of fuel based on the output of the sender unit 103.

[0003] Furthermore, as shown in FIG.
Some vehicles are equipped with a remaining fuel level warning device 110 that lights up a lamp 106 to warn the driver when the remaining amount of fuel in the fuel tank 102 falls below a predetermined amount (for example, 8 liters). This lamp 106 is connected to the fuel tank 1
When the fuel in 02 becomes low and the thermistor 107, which works as a detection switch, goes out of the fuel, the thermistor 107
As the temperature rises and the resistance decreases, the light turns on. Here, 108 is a car battery, and 109 is a key switch. Note that, as shown in FIG. 9, the thermistor 107 is integrally attached to the sender unit 103 at a different position from the float 101.

0004

However, in the prior art, the float 10 that determines the indicated position of the pointer 104 is
1 and a thermistor 107 that determines the lighting timing of the lamp 106.
The mounting position is different. Therefore, as shown in FIG. 9, when the car is stopped, the thermistor 107 is immersed in the fuel, but as shown in FIG. When the liquid level of the fuel fluctuates, the thermistor 107 may or may not be immersed in the fuel.

As a result, the pointer 1 of the automobile fuel gauge 100
The lamp 106 may not be lit even if the indicator 04 reaches the indicated position at which the lamp 106 should be lit, or the pointer 104 may not have reached the indicated position at which the lamp 106 should be lit even if the lamp 106 is lit. Therefore, in the prior art, whenever the remaining amount of fuel in the fuel tank 102 drops below a predetermined amount, the position of the pointer 104 and the lamp 10
There was a problem in that the timing of lighting of 6 was different from that of 6. SUMMARY OF THE INVENTION An object of the present invention is to provide a fluid level indicator for a vehicle that prevents the fluid level displayed by the display means from being different from the warning timing of the warning means.

[0006]

[Means for Solving the Problems] The present invention includes a detection means for detecting a liquid level in a container mounted on a vehicle and outputting a liquid level signal, and a detecting means for detecting a liquid level in a container mounted on a vehicle and outputting a liquid level signal, and and a warning means that warns that the liquid level in the container is below a predetermined amount when the liquid level signal reaches a predetermined value. did.

[0007]

[Operation] The present invention provides display means for displaying the amount of liquid in the container;
and a warning means for warning that the amount of liquid in the container is less than a predetermined amount operate based on a liquid level signal output from the detection means for detecting the liquid level in the container. Therefore, each time the amount of liquid in the container drops below a predetermined amount, the amount of liquid displayed by the display means and the warning timing of the warning means will not differ due to fluctuations in the liquid level in the container or the like.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A vehicle fluid level indicator according to the present invention will be explained based on an embodiment shown in FIGS. 1 to 5. FIG. 1 is a diagram schematically showing a fuel gauge for an automobile. The automobile fuel gauge 1 includes a sender unit 2, a computer 3, and a receiver unit 4.
and a warning lamp 5. Note that 6 is a battery, and 7 is an ignition switch.

The sender unit 2 is a detection means of the present invention, and includes a float 9 and a sliding resistance (not shown) that move according to changes in the liquid level of fuel in a fuel tank 8, which is a container mounted on an automobile. As the float 9 moves, the position of the contact that slides on the sliding resistance changes, and the electrical resistance value changes. Then, the sender unit 2 converts the change in electrical resistance value into a voltage value as a liquid level signal and sends it to the computer 3.

The computer 3 includes an A/D conversion circuit 10,
It is comprised of a data processing circuit 11, an output setting circuit 12, a lighting timing determination circuit 13, and the like. A/D conversion circuit 1
0 is a circuit that converts the voltage value (analog value) related to the liquid level sent from the sender unit 2 into a digital value. This A/D conversion circuit 10 has xn
Convert to a digital value obtained from = (vn/5) x 255. For example, when vn=0V, it is converted to a digital value of 0, and when vn=5V, it is converted to a digital value of 255.

The data processing circuit 11 is a circuit that averages data to determine a target value. This target value (Fxn) is obtained by averaging the past seven digital values and the current digital value, for example (xn+xn-1+...+xn-7)/8.

The output setting circuit 12 sets the previous output value (Fn
-1) and the current target value (Fxn), and even if the difference between the two is large, the pointer 19 is compared with the previous indicated position of the pointer 19, that is, the previous output value (Fn-1). Find the output value (Fn) that can be moved by the resolution. This output value (Fn) is converted into a frequency signal (fn) as shown in Table 1 below, for example, and transmitted to the receiver unit 4.

[0013]

[Table 1]

Further, the output setting circuit 12 transmits the frequency signal (fn) to the receiver unit 4 and then continues to transmit the same frequency signal (fn) for a set time (for example, 10 seconds) regarding the fuel consumption rate. Note that the set time can be freely changed within this range, since the indication of the pointer 19 will not be inaccurate as long as it is earlier than the fuel consumption time of the automobile.

The lighting timing determination circuit 13 determines the output value (Fn)
reaches a set value (Fw; for example, the same value as the output value that is output so that the pointer 19 is positioned at the indicated position indicated by the broken line in FIG. 4) corresponding to the predetermined amount of fuel (for example, 4 liters to 10 liters). This is a circuit that determines whether or not the This lighting timing determination circuit 13 continues to send a low level output to the driving circuit 22 of the warning lamp 5 when Fn=Fw.

The receiver unit 4 includes a crossed coil gauge 14 and a drive circuit 15. As shown in FIGS. 2 and 3, the crossed coil gauge 14 has a permanent magnet 1
A coil 17 is crossed around 6, and the magnetic field rotates a pointer 19 as a display means fixed to the end of a rotating shaft 18 fixed to a permanent magnet 16.

Note that the pointer 19, as shown in FIG.
It moves on the dial 20 displaying F (Full) and E (Empty) at a deflection angle of, for example, 80° about the rotating shaft 18. Further, around the permanent magnet 16, silicone oil (viscosity of about 1,000 to 10,000 cst) 21 is injected. The drive circuit 15 has a well-known structure, and controls the amount of energization of the intersecting coils 17 based on the input frequency signal, and controls the pointer 19 at a resolution (maximum deflection angle of 80 degrees, 80 degrees in the case of an 8-bit computer 3). /256≒0.31°)
Increase or decrease by increments.

The warning lamp 5 is a warning means of the present invention, and is for warning the driver that the remaining amount of fuel in the fuel tank 8 has fallen below a predetermined amount (for example, 8 liters), as shown in FIG. As shown in FIG. 2, it is attached near the pointer 19. This warning lamp 5 is connected to the computer 3 via a drive circuit 22, as shown in FIG. The drive circuit 22 includes transistors 23, 2
4, resistors 25 to 28 and a diode 29.

Note that when the output of the computer 3 is at a high level (hereinafter referred to as H level), the warning lamp 5 is turned off because both the transistors 23 and 24 are turned off, so that the warning lamp 5 is not conductive and is turned off. Furthermore, when the output of the computer 3 is at a low level (hereinafter referred to as L level), both transistors 23 and 24 are turned on, so that the warning lamp 5 is supplied with power from the battery 6 and is turned on.

FIG. 5 is a flow chart showing the operation of the computer 3. This flowchart shows how to drive the pointer 19 from the E position until the pointer 19 indicates the current remaining amount of fuel in the fuel tank 8 after the ignition switch 7 is turned on, or to set the H level to the drive circuit 22 of the warning lamp 5. This is done after initial settings such as transmitting output.

First, a voltage value (analog value) as a liquid level signal sent from the sender unit 2 is converted into a digital value (step S1). Next, for example (
The current target value (Fx
n) is determined (step S2). Subsequently, it is determined whether the previous output value and the current target value are the same value (Fn-1=Fxn) (step S3). When the values are the same (Yes), control in step S1 is performed.

[0022] In step S3, if the values are not the same (
No), the current target value is smaller than the previous output value (F
n-1>Fxn) (step S4). When Fn-1>Fxn is not satisfied (No), an output value {Fn=(Fn-1)+1} that can increase the resolution of the pointer 19 (about 0.3° per deflection angle) is determined (step S5). ).

Subsequently, the output value (Fn) is converted into a frequency signal (fn) (step S6), and the frequency signal (fn) is transmitted to the drive circuit 15 (step S7). It is determined whether a set time (for example, 10 seconds) has elapsed since the frequency level signal (fn) was transmitted (step S8). If the set time has not elapsed (No), control is performed in step S8, and it is determined that the set time has elapsed (Y).
es), control in step S1 is performed.

[0024] In step S4, Fn-1>Fxn
(Yes), the pointer 19 has a resolution (one deflection angle of approximately 0.3
The liquid level signal {Fn
=(Fn-1)-1} (step S9). Next, check whether the flag is on or not.
g=1) (step S10). Fla
When g=1 (Yes), control in step S6 is performed.

In step S10, when Flag=1 (No), the output value (Fn) is a set value (Fn) corresponding to a predetermined amount of fuel (for example, 4 liters to 10 liters).
w) has been reached (Fn=Fw) (step S11). When Fn=Fw does not hold (No), control in step S6 is performed.

When Fn=Fw (Yes), the flag (F
lag) (step S12), and transmits an L level output to the drive circuit 22 of the warning lamp 5 (step S13). After that, control in step S6 is performed.

The operation of this automobile fuel gauge 1 will be explained based on FIGS. 1 to 6. Generally, when an automobile suddenly accelerates, decelerates, turns sharply, or drives on a steep slope, the fuel level in the fuel tank 8 fluctuates greatly, and the float 9 of the sender unit 2 also vibrates greatly up and down. The output of unit 2 also changes significantly.

For this reason, the A/D conversion circuit 10 of the computer 3 receives the previous voltage value (vn-1: for example 2.20V).
Voltage value significantly reduced from (vn: e.g. 0.35V)
is input. Then, this input voltage value (vn) is converted by the A/D conversion circuit 10 to xn=(vn/5)×
The data is converted into a digital value (xn) determined based on H.255 and sent to the data processing circuit 11.

Then, in the data processing circuit 11, the current digital value (xn) is equal to the previous seven digital values (xn
-1+...+xn-7) to obtain the current target value (Fxn). Next, output setting circuit 1
2, the previous output value (Fn-1) and the current target value (Fx
n), and it is determined that the current target value (Fxn) has significantly decreased from the previous target value (Fn-1).

Even in the above-mentioned case, the output setting circuit 12 moves the pointer 19 toward E by only the resolution (one deflection angle of about 0.3°) compared to the previous output value (Fn-1). Find the possible output value (Fn), and calculate the output value (Fn)
is converted into a frequency signal (fn) and transmitted to the drive circuit 15 of the receiver unit 4.

That is, a liquid level signal is transmitted that prevents the pointer 19 from moving several deflection angles at once. Therefore, the drive circuit 15 moves the pointer 19 by one deflection angle (approximately 0.3°) from the previously indicated position. Then, after the pointer 19 moves, the frequency signal (liquid level signal: f
By continuing to send the signal n) to the drive circuit 15, the pointer 19 is held at the indicated position for a set time (for example, 10 seconds), so the remaining amount of fuel in the fuel tank 8 can be easily confirmed.

Therefore, even if the value of the output voltage of the sender unit 2 temporarily changes significantly, the pointer 19 does not swing significantly and moves very slowly to the indicated position at each set time. Note that if the set time for holding the indicated position is set earlier than the fuel consumption time based on the fuel consumption of the automobile, the indicated position of the pointer 19 will not deviate from the normal indicated position. Therefore, since the pointer 19 always indicates a substantially normal pointing position, it is possible to provide a highly reliable automobile fuel gauge 1.

[0033] As the vehicle continues to be driven, the liquid level in the fuel tank 8 gradually decreases until the remaining fuel level (for example, 4 to 10 liters) is enough to cause the warning lamp 5 to light up. The computer 3, which receives the liquid level signal corresponding to the liquid level at this time from the sender unit 2, uses the output setting circuit 12 to set the output value (Fn
) is converted into a frequency signal (fn) and transmitted. Therefore, the pointer 19 is driven to the indicated position based on the frequency signal (fn).

Furthermore, the lighting timing determination circuit 13 of the computer 3 determines the output value (
Compare Fn) with a preset setting value (Fw),
If it is determined that Fn=Fw, the warning lamp 5
It sends an L level output to the drive circuit 22 of. Then,
The warning lamp 5 lights up to inform the driver that the remaining fuel level has decreased to, for example, 4 to 10 liters.

Therefore, the sender unit 2 is connected to the pointer 19.
By functioning as a sensor that outputs a signal to determine the indicated position of the pointer 19 and a signal that determines the lighting timing of the warning lamp 5, the indicated position of the pointer 19 and the lighting timing of the warning lamp 5 are determined based on the liquid in the fuel tank 8. It is possible to avoid the phenomenon of differences due to changes in surface level, etc. Further, unlike the prior art, there is no possibility that the mounting positions of the sender unit and the detection switch such as a thermistor vary, so there is no variation in the lighting timing of the warning lamp 5.

Furthermore, in the prior art, the liquid level in the fuel tank 8 fluctuates greatly when the vehicle suddenly accelerates, decelerates, turns sharply, or runs on a steep slope, causing a detection switch such as a thermistor to become immersed in the fuel. There was a problem where the warning lamp would turn on and off depending on whether the product was soaked or not immersed. However, in this embodiment, once the warning lamp 5 lights up, the refueling signal (for example, the ignition switch 7
is on and the liquid level signal of the F (full) point is being input from the sender unit 2, or when the output value (Fn
) can be controlled so as not to turn off the warning lamp 5 until the value (Fw) becomes considerably larger than the set value (Fw), it is possible to eliminate the problems that occur in the prior art as described above.

(Modification) In this embodiment, the present invention was applied to an automobile fuel gauge, but the present invention can also be applied to engine cooling water, brake fluid, various oils such as engine oil, and vehicle fluids such as window washer fluid. It may also be applied to quantity indicating instruments. In this embodiment, a device in which the pointer rotates about a fulcrum is used, but a device in which the pointer moves reciprocatingly may also be used. Further, in this embodiment, a pointer is used as a display means, but a liquid crystal display or the like may be used as a display means to display characters or pictures.

In this embodiment, a frequency signal is used as the liquid level signal, but an electric signal such as a voltage signal or a current signal, or an electric signal + fluid pressure signal may also be used as the liquid level signal. Further, in this embodiment, the pointer is moved by one deflection angle, but the pointer may be moved by a plurality of deflection angles. Further, an electric circuit that does not use the computer 3 may be interposed between the receiver unit 4 and the warning lamp 5 and the sender unit 2.

As the driving circuit for the warning lamp 5, the one shown in FIG. 6 may be used. This drive circuit 30 is composed of a transistor 31, resistors 32, 33, and a diode 34, and turns on the warning lamp 5 when an H level output is input from the computer 3, and turns off the warning lamp 5 when an L level output is input. do.

[0040]

Effects of the Invention: Even if the liquid level in the container fluctuates, the display means displays the liquid amount and the warning means warns that the liquid level in the container has fallen below a predetermined amount. Since the warning times can be made equal to each other, it is possible to provide a highly reliable vehicle fluid level indicator.

[Brief explanation of drawings]

FIG. 1 is a block diagram schematically showing a fuel gauge for an automobile.

FIG. 2 is a plan view showing a crossed coil type gauge.

FIG. 3 is a sectional view showing a crossed coil type gauge.

FIG. 4 is a plan view showing hands and a dial.

FIG. 5 is a flowchart showing the operation of the computer.

FIG. 6 is an electrical wiring diagram showing a modification of the warning lamp drive circuit.

FIG. 7 is a structural diagram showing a conventional automobile fuel gauge.

FIG. 8 is a structural diagram showing a conventional fuel remaining amount warning device.

FIG. 9 is a schematic diagram showing the liquid level of the fuel tank when the vehicle is stopped in the prior art.

FIG. 10 is a schematic diagram showing the liquid level of the fuel tank during cornering in the prior art.

[Explanation of symbols]

1 Automotive fuel gauge (vehicle fluid level indicator) 2 Sender unit (detection means) 4 Receiver unit 5 Warning lamp (warning means) 8 Fuel tank (container) 19 Pointer (display means)

Claims (1)

[Claims] 1. (a) detection means for detecting a liquid level in a container mounted on a vehicle and outputting a liquid level signal; and (b) detecting means for detecting a liquid level in the container in accordance with the liquid level signal. A vehicle liquid comprising: a display means for displaying the amount; and (c) a warning means for warning that the liquid amount in the container is less than a predetermined amount when the liquid level signal reaches a predetermined value. Quantity indicating instrument.