JPH0574954U - Liquid level measuring device for fuel tanks - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a liquid level measuring device for a fuel tank, which can continuously change an indicated value of fuel as the amount of fuel decreases and display an accurate residual liquid amount of fuel. A main sensor 62 for detecting the liquid level in the main tank chamber 3, a sub sensor 60 for detecting the liquid level in the sub tank chamber 5 stepwise, a liquid level signal of the main sensor and the step detection of the sub sensor. The addition means 64 for adding the signals, the correction means 66 for correcting the total remaining liquid amount signal according to the rotation signal output from the rotation sensor 67, and the value of the total remaining liquid amount signal corrected by the correction means 66 are displayed. When the level detection signal of the liquid level detected by the sub-sensor 60 changes from a higher level to a lower level value, the correction means 66 is output from the adding means immediately before the change. A time constant circuit for decreasing the value of the total residual liquid amount signal according to the rotation signal with a lapse of time is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fuel tank liquid level measuring device in which a main tank chamber and a sub tank chamber are provided in a lower portion of a tank body.

[0002]

[Prior Art]

 For example, as a fuel tank for an automobile, the one shown in FIG. 7 is known.

In FIG. 7, reference numeral 1 denotes a tank body of a fuel tank, and a bulging portion 2 is formed inwardly on a bottom wall of the tank body 1 so that a main tank chamber 3 and a sub tank chamber 5 are separated from each other. Has been done. The bulging portion 2 is formed to avoid interference between the bottom wall of the tank body and the functional parts of the vehicle body.

Reference numeral 7 denotes a feed pipe for feeding the fuel in the main tank chamber 3 to a fuel supply device for supplying an engine (not shown), and a feed pump 8 is attached to its suction end.

Reference numeral 9 is a vertical type fuel gauge, which has a float 10 that moves up and down according to the liquid level, and detects the liquid level by changing the resistance value depending on the position of the float 10. Then, the liquid level from the bottom of the main tank chamber 3 to the upper end of the tank body 1 is detected.

Reference numeral 11 denotes a return pipe for returning excess fuel not consumed by the fuel supply device into the tank body 1, and a nozzle 13 projecting into the chamber 12 is formed at the tip of the return pipe 11. A throttle portion 14 is formed in the lower part of the chamber 12, and the throttle portion 14 is arranged in the main tank chamber 3. Reference numeral 15 is a suction pipe that connects the chamber 12 and the sub-tank chamber 5, and one end of the suction pipe is connected to the suction passage 16 of the sub-fuel gauge 20.

The sub-fuel gauge 20 detects the liquid level in the range from the bottom of the sub-tank chamber 5 to the upper end of the bulge portion 2. The sub-fuel gauge 20 is disposed in the float chamber 21. A float 22 that moves up and down according to the above, and a reed switch 23 that is turned on / off by the float 22 are provided.

The reed switch 23 is turned on when the float 22 is in a raised position, and is turned off when the float 22 is in a lowered position.

Now, when the feed pump 8 is driven, fuel is supplied from the main tank chamber 3 to the fuel supply device via the feed pipe 7, and the surplus fuel supplied to this fuel supply device is supplied to the return pipe 11. It is returned to the inside of the tank body 1 via.

At this time, the fuel is jetted vigorously from the nozzle 13 toward the throttle portion 14 by the discharge pressure of the feed pump 8. Therefore, a negative pressure region is generated around the nozzle 13 in the chamber 12, and the negative pressure causes the fuel in the sub tank chamber 5 to be transferred to the main tank chamber 3 via the suction passage 16 and the suction pipe 15. The suction pipe 15, the chamber 12, the throttle portion 14, the return pipe 11, the nozzle 13 and the like constitute a transfer unit Q 1.

Here, the remaining fuel amount in the tank body 1 is confirmed by the fuel meter 17, and the display values of the fuel meter 17 remain in the main tank chamber 3 and the sub tank chamber 5. The total value of fuel is displayed.

That is, when the liquid level in the sub-tank chamber 5 is above a certain level, the reed switch 23 is turned on when the float 22 is raised, and when the liquid level is below a certain value, the float 22 is lowered and the reed switch 23 is turned off. Then, the detected value of the fuel gauge 12 in the main tank chamber 3 is corrected and displayed on the fuel meter 17.

[0013]

[Problems to be solved by the device]

 By the way, the sub-fuel gauge 20 detects the residual liquid amount of the fuel in the sub-tank chamber 5 by turning on / off one reed switch 23. In other words, since it is sufficient to detect whether or not there is fuel in the sub tank chamber 5 by turning on / off the reed switch 23, the total amount of fuel displayed on the fuel meter 17 is quite inaccurate. was there.

In order to solve this problem, if the same fuel gauge of the vertical type as that of the main tank chamber 3 is used, an accurate total amount of fuel can be obtained, but it is expensive. There is.

Therefore, the sub-fuel gauge 20 is provided with three reed switches connected in series in the vertical direction, and the liquid level of the sub tank chamber 5 is detected in three stages by turning on / off these reed switches. Has proposed a liquid level measuring device which corrects the detected value of the fuel gauge 9 according to its three levels and displays it on the fuel meter 17.

However, even with this liquid level measuring device, since the liquid level of the sub tank chamber 5 is only detected in three stages, the total amount of fuel displayed on the fuel meter 14 is still inaccurate. In addition, since the pointer of the fuel meter 14 moves in a stepwise manner, there is a problem that the user feels distrust.

The present invention has been made in view of the above problems, and an object thereof is to obtain an accurate residual fuel amount of a fuel with an inexpensive configuration, in which the display value of the fuel continuously changes as the fuel decreases. It is to provide a liquid level measuring device for a fuel tank capable of displaying the total amount.

[0018]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention has a main tank chamber and a sub tank chamber formed in a lower portion of a tank body, a feed pipe for feeding fuel in the main tank chamber to an engine, and a feed pipe. Level of the fuel in the range from the bottom of the main tank chamber to the top of the tank body of the fuel tank equipped with a suction pipe that sends the fuel in the sub-tank chamber to the main tank chamber by the In a liquid level measuring device for a fuel tank provided with a main sensor for detecting the liquid level and outputting a liquid level signal according to the liquid level, a rotation sensor for outputting a rotation signal according to the engine speed, The range from the bottom to the top of the sub-tank chamber is divided into several stages, the stage where the liquid level of the fuel in the sub-tank chamber is located is detected, and the stage detection signal corresponding to the detected stage is output. With sub sensor An adding means for outputting a total residual liquid amount signal obtained by adding the values of the liquid level signal of the main sensor and the stage detection signal of the sub sensor; and the total residual liquid amount according to the rotation signal output by the rotation sensor. A correction means for correcting the signal, and a display means for displaying the value of the total residual liquid amount signal corrected by the correction means are provided, wherein the correction means has a higher level detection signal of the liquid level detected by the sub-sensor. When the value changes from the step to the value of the lower step, the value of the total residual liquid amount signal output from the adding means immediately before the change is decreased with the passage of time at a rate according to the value of the rotation signal. It is characterized by having a time constant circuit that keeps going.

[0019]

[Action]

 With this configuration, the invention detects the stage where the liquid level of the fuel in the sub tank chamber is located, outputs a stage detection signal corresponding to the detected stage, and the adding means outputs the liquid level signal of the main sensor. And the value of the step detection signal of the sub-sensor is added to output the total residual liquid amount signal. Then, when the liquid level level detection signal detected by the sub-sensor is detected by the time constant circuit of the correction means, the total residual liquid volume output from the addition means immediately before the displacement when the detection signal changes from the upper level to the lower level The value of the signal is decreased over time at a rate according to the value of the rotation signal output from the rotation sensor, and the display means displays the value of the total residual liquid amount signal corrected by the correction means.

[0020]

【Example】

 An embodiment of a liquid level measuring device for a fuel tank according to the present invention will be described below with reference to the drawings. The same members as those shown in FIG. 7 are designated by the same reference numerals and the description thereof will be omitted.

2 to 4, reference numeral 50 denotes a sub-fuel gauge for detecting the liquid level in the range from the bottom of the sub tank chamber 5 to the upper end of the bulging portion 2. The sub-fuel gauge 50 is It is composed of a tubular casing 26 and a reed switch unit 27 attached to the lower portion of the casing 26.

The casing 26 has the flange portion 25 formed on the upper portion and the suction passage 16 as a suction pipe extending to the bottom wall of the tank body 1, and is formed on the upper surface of the tank body 1. A lower end of a connector 30 as a suction pipe integrally formed with a lid 29 that closes the formed mounting hole 18 is received in the suction passage 16 and the chamber 12 is connected via the suction pipe 15 connected to the connector 30. The negative pressure generated inside sucks up the fuel in the sub tank chamber 5.

The tip of the suction passage 16 is formed thinner than the portion that receives the connector 30, and a partition wall 31 surrounds the tip of the suction passage 16 and the suction wall 16 sucks the outer wall of the suction passage 16. A donut-shaped float chamber 32 having an open lower side is provided between the channel 16 and the partition wall 31. In the float chamber 32, a float 35 having a magnet 34 for actuating reed switches 33a, 33b, 33c provided in a lead switch portion 33 described later is provided so as to be vertically movable.

In addition, an upper stopper 36 of the float 35 is formed on the upper wall of the partition wall 31 and a communication hole 37 is formed to take in air when the fuel level is lowered. A suction port 38 is formed at the edge.

The flange portion of the caging 26 is attached to the attachment hole 18 by a predetermined fixing means, and a seal member 39 is attached to a portion for receiving the connector 30 via a stopper 40.

On the other hand, the reed switch unit 27 attached to the lower part of the caging 26 closes the lower part of the caging 26 and has a plate 43 having a claw 42 that engages with a hook 41 provided on the partition wall 31, and this plate 43. A well-known reed switch 33a to 33c which is turned on and off by the float 35 is provided at the tip of the terminals 44a, 47a and 47b, which are integrally formed at the central portion of the terminal 44a, 44b, 47a, 47b. The reed switch unit 33 is attached.

When the plate 43 is attached to the lower part of the casing 26 and the claw 42 of the plate 43 is attached to the hook 41 of the partition wall 31 by engaging, the terminal 44 is inserted into the suction passage 16 of the casing 26, and the reed switch part is inserted. 33 will be arranged in the suction path 16.

A lower stopper 45 of the float 35 is integrally formed on the upper surface of the plate 43. Further, the respective end portions of the terminals 44, 44 extend in the circumferential direction of the plate 43 so as to be arranged outside the periphery of the partition wall 31 of the casing 26 when the plate 43 is attached to the casing 26, and stand upright. Has been raised.

By the way, the reed switches 33a to 33c are arranged in order from the top of the reed switch portion 33, and the reed switch 33a is arranged such that the liquid level of the fuel in the sub tank chamber 5 is lowered and the float 35 is lifted from the bottom. Is turned on when the float falls below H1, the reed switch 33b is turned on when the float 35 is lowered below the height H2 (<H1), and the reed switch 33c is turned on when the float 35 is lowered below the height H3 (<H2). It does.

As shown in FIG. 5, these reed switches 33a to 33c are connected so as to short-circuit the resistors R1, R2 and R3. The resistors R1 to R3 and the reed switches 33a to 33c and the like form a sub sensor 60, and the terminal 47b is connected to the averaging circuit 61 shown in FIG.

The sub-sensor 60 changes the combined resistance between the terminals 44b and 47b in three steps by turning on / off the reed switches 33a to 33c, and outputs a voltage (step detection signal) corresponding to the combined resistance to the averaging circuit 61. It is output. That is, the sub sensor 60 detects the liquid level when it becomes H1, H2, H3.

Further, in FIG. 2, reference numeral 62 denotes a main sensor composed of a vertical type fuel gauge similar to the conventional one, which changes a resistance value depending on the position of the float 10 and changes a voltage (liquid level) according to the resistance value. By outputting the level signal), the liquid level from the bottom of the main tank chamber 3 to the upper end of the tank body 1 is detected.

FIG. 1 is a block diagram showing a configuration of an electric system of a liquid level measuring device according to the present invention.

In FIG. 1, reference numeral 61 denotes a stage detection signal output from the sub sensor 60, for example, every 0.1 seconds, and the sampled stage detection signals are averaged, for example, every 1 second, and the averaged average stage signal SD Is an averaging circuit that outputs Reference numeral 63 is an averaging circuit that samples the liquid level signal output from the main sensor 62 in the same manner as above and outputs the averaged average liquid level signal SM.

Reference numeral 64 is an adding circuit (adding means) for adding the average step signal SD and the average liquid level signal SM to obtain the total residual liquid amount in the tank body 1 and outputting an addition signal SG indicating the total residual liquid amount. ), 65 is an averaging circuit that averages the addition signal SG output from the addition circuit 64, for example, every tens of seconds, and outputs the averaged average addition signal SH every tens of seconds. These averaging circuits 61, 63 and 65 are for removing the influence of the fluctuations because the liquid level fluctuates due to rocking of the vehicle body or the like.

Reference numeral 66 denotes a correction circuit (correction means) provided with a time constant circuit for correcting the average addition signal SH. The correction circuit 66 outputs the rotation signal SK output from the rotation sensor 67 for detecting the engine speed. The corrected addition signal SJ is output by reducing the average addition signal SH with the passage of time at a rate according to the value. Reference numeral 68 denotes a display device (display means) for displaying the total residual liquid amount of fuel according to the value of the correction addition signal SJ, and this display device 68 is displayed by the drive circuit 69.

Reference numeral 71 compares the average liquid level signal SM output from the averaging circuit 63 with the average addition signal SH output from the averaging circuit 65, and when the difference is below a predetermined value, the average liquid level signal. This is an abnormality processing circuit that outputs SM, cancels the output of the average liquid level signal SM when it is judged to be abnormal when the difference exceeds a predetermined value.

Reference numeral 72 compares the average step signal SD output from the averaging circuit 61 with the average addition signal SH output from the averaging circuit 65, and outputs the average step signal SD when the difference is less than a predetermined value. The abnormality processing circuit cancels the output of the average step signal SD when it judges that the difference is abnormal when the difference is equal to or more than a predetermined value.

The abnormality processing circuits 71 and 72 remove the signals detected by the sensors 60 and 62 when the liquid level greatly changes due to the swing of the vehicle body or the like.

Reference numeral 73 is an averaging circuit that averages the average liquid level signal SM output from the abnormality processing circuit 71, for example, every tens of seconds, and outputs the averaged average liquid level signal SL, and 74 is an abnormality processing circuit. This is an averaging circuit for averaging the average step signal SD output from 72 every several tens of seconds and outputting the average step signal SP.

Reference numeral 75 is a set value in which the average liquid level signal SL output from the averaging circuit 73 is less than or equal to a preset set value A, and the average step signal SP output from the averaging circuit 74 is set in advance. When B (<A) or more, the transfer unit Q has failed and the fuel in the sub tank chamber 5 is judged not to have been transferred to the main tank chamber 3.

When the failure judging circuit 75 judges that the transfer unit Q is out of order, it outputs a reset signal R, and the reset signal R causes the adding circuit 64 to output the average step signal SD output from the averaging circuit 61. Treat the value as zero.

Next, the operation of the above embodiment will be described with reference to the time chart shown in FIG.

As shown in FIG. 6A, when the fuel is consumed from the state where the tank body 1 is filled with the fuel, the liquid level of the fuel is lowered. All of the reed switches 33a to 33c of the sub sensor 60 are turned off until the liquid level drops to the position of the height H1 from the bottom of the sub tank chamber 5. Therefore, from time t0 to time t1 (time when the lead switch 33a is turned on) shown in FIG. 6, the sub sensor 60 outputs a step detection signal having a constant value.

On the other hand, the main sensor 62 outputs a liquid level signal according to the decrease of the liquid level. The averaging circuit 63 outputs the averaged average liquid level signal SM, and the averaging circuit 61 outputs the averaged average step signal SD.

The addition circuit 64 outputs an addition signal S G obtained by adding the average liquid level signal SM and the average stage signal SD, and the averaging circuit 65 averages the addition signal S G output from the addition circuit 64. SH is output, for example, every several tens of seconds.

If the fuel is consumed at a constant rate, the value of the average addition signal SH is a value that is lowered along the straight line from the time point t0 to the time point t1 in FIG. 6C.

Then, the correction circuit 66 outputs the value of the average addition signal SH output from the averaging circuit 65, for example, the value of SH1 from the output of the signal SH1 at time ta to the output of the signal SH2 at time tb. Then, the correction addition signal SJ1 (see (D) of FIG. 6) that decreases with the passage of time is output. This correction addition signal SJ1 is output by a time constant circuit and decreases exponentially, but since the time from time ta to time tb is about several tens of seconds, it can be regarded as a substantially straight line ( The time constant is set so that it can be regarded as a straight line). The time constant is determined according to the rotation signal output from the rotation sensor 67.

Then, the total residual liquid amount of the fuel, which is the value of the correction addition signal SJ1, is displayed on the display 68 by the driver 69.

When the liquid level surface of the fuel is lowered to the position of the height H1, the reed switch 33a is turned on (time point t2). When the reed switch 33a is turned on, the resistor R1 shown in FIG. 5 is in a short-circuited state, so that the value of the stage detection signal output from the sub-sensor 60 suddenly drops. As a result, the average addition signal SH output from the averaging circuit 65 also drops sharply at time t2. For example, as shown in FIG. 6C, the average addition signal SH changes from SH3 to SH4.

Then, the time constant circuit 66 outputs the corrected addition signal SJ2 which decreases from the value of the average addition signal SH3 with the passage of time (see (D) of FIG. 6). The correction addition signal SJ2 determines the time constant according to the rotation signal SK output from the rotation sensor 67, and the time constant circuit (not shown) outputs the time constant based on the determined time constant. is there.

The value of the time constant is determined so that the correction addition signal SJ2 greatly decreases with the passage of time because the fuel consumption is large when the value of the rotation signal SK is large.

The averaging circuit 65 outputs the average addition signal SH4 several times until the time t2, but when the value of the correction addition signal SJ2 is larger than the value of the average addition signal SH4, the correction circuit 66 outputs the correction addition signal SJ2. Is output, the correction addition signal SJ2 is output until time t2.

Similarly, at time points t2 and t3, the liquid level of the sub tank chamber 5 drops to H2 and H3, the lead switches 30b and 30c are turned on, and the averaging circuit 65 outputs the average addition signals SH5 and SH6. Also in this case, the correction circuit 66 outputs the correction addition signals SJ3 and SJ4 which decrease with the passage of time. Then, the total residual liquid amount of the fuel, which is the value of the correction addition signals SJ3 and SJ4, is displayed on the display 68.

As described above, even when the sub sensor 60 detects the liquid level of the sub tank chamber 5 in three stages and the average addition signal SH output from the average circuit 65 changes stepwise, the time constant circuit Since the correction addition signal SJ that decreases with the passage of time is corrected by 66, the display value of the display 68 changes continuously according to the decrease of the fuel, and the display value is almost accurate. The remaining liquid amount of various fuels will be displayed. Further, since the sub sensor 60 uses the reed switches 30a to 30c, the liquid level measuring device becomes inexpensive.

On the other hand, the abnormality detection circuit 71 compares the average liquid level signal SM output from the averaging circuit 63 with the average addition signal SH output from the averaging circuit 65, and when the difference is below a predetermined value. The average liquid level signal SM is output. When the difference is equal to or more than a predetermined value, it is determined that the output is abnormal and the output of the average liquid level signal SM is canceled.

Similarly, the abnormality processing circuit 72 compares the average step signal SD output from the averaging circuit 61 with the average addition signal SH output from the averaging circuit 65, and when the difference is less than a predetermined value, The average step signal SD is output, and when the difference is equal to or more than a predetermined value, it is determined to be abnormal and the output of the average step signal SD is canceled.

Then, the averaging circuit 73 averages the average liquid level signal SM output from the abnormality processing circuit 71, for example, every tens of seconds, and outputs the averaged average liquid level signal SL. Similarly, the averaging circuit 74 averages the average step signal SD output from the abnormality processing circuit 72, for example, every tens of seconds, and outputs the averaged average liquid level signal SP.

The failure determination circuit 75 outputs the average liquid level signal SP output from the averaging circuit 74 when the average liquid level signal SL output from the averaging circuit 73 is less than or equal to a preset set value A. Is greater than a preset value B (<A), a reset signal D is output because it is determined that the transfer unit Q is out of order. With this reset signal D, the adder circuit 64 processes the value of the average step signal SD output from the averaging circuit 61 as zero.

That is, the adding circuit 64 outputs the average liquid level signal SM output from the averaging circuit 63. As a result, only the residual liquid amount of the fuel in the main tank chamber 3 is displayed on the display 68, and when the fuel in the sub tank chamber 5 cannot be used due to the failure of the transfer unit Q, the residual liquid amount in the sub tank chamber 5 is displayed. Will not be done.

Therefore, the driver can drive with confidence in the “EMPTY” display on the display 68. By the way, if the transfer unit Q is out of order and the fuel in the sub tank chamber 5 cannot be used, but the residual liquid amount in the sub tank chamber 5 is displayed, the indicator 68 displays “EMPTY”. Even if it is not done, there is a problem that it becomes incapable of traveling due to lack of fuel, and it means that it is not possible to drive with confidence until the display 68 displays "EMPTY".

[0062]

【effect】

 According to this invention, the sub-sensor detects the liquid level in the sub-tank chamber in multiple stages, but since it is corrected by the correction means to a correction signal that decreases with the passage of time, the display value of the display means indicates the fuel level. It will change continuously with the decrease, and the displayed value will also show the almost accurate remaining fuel amount. Further, since the sub-sensor including the reed switch may be used, the liquid level measuring device can be provided at low cost.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an electric system of a fuel tank liquid level measuring device according to the invention;

FIG. 2 is a schematic configuration diagram showing a configuration of a fuel tank,

FIG. 3 is a cross-sectional view showing the configuration of a sub-fuel gauge for detecting the liquid level in the sub-tank chamber,

FIG. 4 is a cross-sectional perspective view in which the sub fuel gauge is partially disassembled,

FIG. 5 is a circuit diagram showing connection between a reed switch and a resistor,

FIG. 6 is a time chart diagram showing signals output by the main circuit of FIG.

FIG. 7 is a schematic explanatory view showing a configuration of a conventional fuel tank liquid level measuring device.

[Explanation of symbols]

 1 Tank Main Body 3 Main Tank Room 5 Sub Tank Room 7 Feed Pipe 15 Suction Pipe 60 Sub Sensor 62 Main Sensor 64 Adder Circuit (Adder Means) 66 Correction Circuit (Correction Means) 68 Display (Display Means)

Claims (1)

[Scope of utility model registration request] 1. A main tank chamber and a sub tank chamber are formed in a lower portion of a tank main body, a feed pipe for feeding fuel in the main tank chamber to an engine, and the feed pipe for feeding the fuel to the engine. A liquid level of the fuel in a range from the bottom of the main tank chamber to the top of the tank body of the fuel tank equipped with a suction pipe for feeding the fuel of the sub tank chamber to the main tank chamber is detected. In a liquid level measuring device for a fuel tank provided with a main sensor that outputs a liquid level signal according to, a rotation sensor that outputs a rotation signal according to the number of revolutions of the engine, and from the bottom to the top of the sub tank chamber The range of is divided into several stages, the stage where the liquid level of the fuel in the sub-tank chamber is located is detected, and a sub-sensor that outputs a stage detection signal according to the detected stage, and the liquid level of the main sensor Position And an adding unit that outputs a total residual liquid amount signal obtained by adding the values of the stage detection signals of the sub-sensors, and a correction unit that corrects the total residual liquid amount signal according to the rotation signal output by the rotation sensor, And a display means for displaying the value of the total residual liquid amount signal corrected by the means, wherein the correction means changes the liquid level step detection signal detected by the sub-sensor from a higher step to a lower step value. At this time, a time constant circuit for decreasing the value of the total residual liquid amount signal output from the adding means immediately before the change with a lapse of time at a rate according to the value of the rotation signal is provided. A fuel tank liquid level measuring device.