DE102006038873A1 - Vehicle remaining fuel quantity detection device, has variable resistance, resistance value measuring section, where resistance value computation section computes resistance value of variable resistance based on ratio of voltage - Google Patents

Abstract

The device has a variable resistance (105a), resistance value measuring section comprising measuring current supply circuit (129). A pulsed current supply circuit (123) supplies electricity to the variable resistance. The resistance value computation section computes the resistance value of the variable resistance based on the ratio of the voltage (Vr) over the opposite ends of the variable resistance to the measuring current (Is). The remaining fuel quantity is estimated from the resistance value of the variable resistance.

Description

BACKGROUND THE INVENTION

1st area the invention

The The present invention relates to a residual vehicle fuel amount detecting device is capable of the residual fuel amount in a fuel tank by Measuring the resistance value of a on the liquid surface of the Fuel floating float operatively associated resistance variable resistance (generally referred to herein as variable resistance) capture. In particular, the invention relates to such a residual vehicle fuel quantity detecting device, which is improved to the detection of the residual fuel amount with achieve high accuracy by suppressing an increase in contact resistance of variable resistance.

2. Description of the prior art

In The past is a variable resistor for capturing the Residual fuel quantity in a fuel tank mounted on a motor vehicle has been widely used in practical use and has become various thoughts about it made, the mechanical service life of such a variable Extend resistance, preventing the contact resistance from increasing, and so on.

As a first example of this kind of conventional devices, for example, there has been proposed a fuel level sensor which is intended to improve its characteristic with respect to the material and the method of manufacturing a variable resistor (for example, see a first patent document: Japanese Patent Application Laid-open No. H11 -211540 ( 4 , Summary)).

In addition, as a second example of the conventional device, there have been proposed a fuel tank level sensor and a residual fuel amount measuring device in which a variable resistor is provided with a linear range and a non-linear range, so that even if the contact resistance of the variable resistor in accordance with Producing a sulfuric acid layer increases, it is possible to detect a specific position or level of the fuel in a fuel tank by detecting the position or the level of the fuel at which the resistance of the variable resistor suddenly changes (see, for example, a second Patent Document: Japanese Patent Application Laid-Open No. 2003-343379 ( 1 , Summary)).

Further, as a third example of the conventional device, there has also been proposed a contact signal identification device in which an oxide layer on a contact surface is destroyed by a repetitive pulse current (see, for example, a third patent document: Japanese Patent Application Laid-open No. H7-14463 ( 1 , Summary)).

however refer to the techniques described in the above-mentioned first and second patent documents disclosed, secondary techniques or improvements to the products itself, but no suggestion for using a variable resistor while of oppression an increase in the contact resistance of the variable resistor the user page.

moreover is the one mentioned in the above Third Patent Document disclosed technology constructed such that a small stream continuously between closed (turned on) Supplied contacts will be and a relatively large one pulsed Current is also supplied therebetween in an intermittent manner, to get a logically inverted output, appealing to a voltage over the closed contacts. Such a construction brings that following problem with it. In the case of a variable resistor with a variable constant resistance component and a constant resistance component connected in series it is difficult to determine if the resistance value component of variable resistance becomes large or the contact resistance component thereof becomes large and becomes simultaneous it's difficult to get a tension over the opposite Measuring variable resistance ends due to the influence the repeatedly pulsating current.

RESUME OF INVENTION

Accordingly, the The present invention is intended to solve the problems identified above to circumvent and has as a goal, a vehicle residual fuel amount detecting means to obtain the resistance of a variable resistor to Measure fuel quantity detection with a high degree of precision can while an increase in the contact resistance of the variable resistor is suppressed.

In view of the above object, according to the present invention, there is provided a vehicle remaining fuel amount detecting means including a variable resistor that is operable to the position of a float floating on the liquid surface of fuel and a resistance value measuring section that measures the resistance value of the variable resistor, the remaining fuel amount being estimated and indicated by the resistance value of the variable resistor measured by the resistance value measuring section. The resistance value measuring section is composed of a measuring current supply circuit and a pulse power supply circuit for supplying electric power to the variable resistor, an A / D converter and a microprocessor. The microprocessor uses a program memory and a RAM memory in combination and control programs which function at least as a read signal generating section and as a resistance value calculating section are stored in the program memory. The fixed resistance resistor (referred to herein generally as the fixed resistor) supplies a measurement current from an on-board battery to the variable resistor to calculate the resistance value thereof. The pulse current supply circuit periodically supplies the variable resistance of an on-board battery with a power supply period to a pulse-shaped current larger than the measurement current to suppress an increase in the contact resistance value of the variable resistor. The analog-to-digital converter digitally converts the value of a voltage across the opposite ends of the variable resistor and the digital conversion data thus obtained is communicated to the RAM memory via the microprocessor based on a read timing signal generated by the read signal generating section. The read signal generating section supplies the read time signal of the read period of the analog-to-digital converter at a timing other than a period in which the pulse-current supply circuit supplies the pulse-shaped current. The resistance value calculating section calculates the resistance value of the variable resistor based on the ratio of the voltage across the opposite ends of the variable resistor to the measuring current, and the amount of residual fuel is estimated from the resistance value of the variable resistor.

According to the present Invention can be achieved by intermittently supplying a pulsating current to the variable resistor for the fuel level detection and by heating the contact surface of the variable resistance and a sliding element an increase of Contact resistance of the variable resistor are suppressed.

moreover it is even a big one pulsed Electricity possible, the generation of heat in the power supply circuit by repeatedly feeding Energy for to suppress a short time periodically. Furthermore, the pulse current supply circuit be built with low cost while avoiding the impact the feeding accuracy of the pulsating current without measuring the voltage across the opposite ends of variable resistance during the feeding of the pulse-shaped Current.

The Above and other objects, features and advantages of the present invention The invention will become apparent to those skilled in the art from the following detailed description preferred embodiments of the present invention, taken in conjunction with the appended Drawings, easier to see.

SUMMARY THE DRAWINGS

It shows:

1 12 is a circuit block diagram of the overall configuration of a vehicle remaining fuel amount detecting device according to a first embodiment of the present invention;

2 FIG. 10 is a flowchart of a first half of the operation processing of a microprocessor according to the first embodiment of the present invention; FIG.

3 a flowchart of a second half of the operation processing of the microprocessor according to the first embodiment of the present invention;

4 a flowchart of the operation processing of a second microprocessor according to the first embodiment of the present invention;

5 FIG. 10 is a circuit block diagram of a vehicle remaining fuel amount detecting device according to a second embodiment of the present invention; FIG.

6 a flowchart of a first half of an operation processing according to the second embodiment of the present invention; and

7 a flowchart of a second half of the operation processing according to the second embodiment of the present invention.

DESCRIPTION THE PREFERRED EMBODIMENTS

Now become preferred embodiments of the present invention with reference to the attached Drawings described.

Embodiment 1.

1 is a circuit block diagram that shows the overall configuration of a vehicle remaining fuel amount detecting device according to a first embodiment of the present invention.

In 1 is the generally with 10A characterized residual vehicle fuel quantity detecting means primarily with a variable resistor 105a for the fuel level detection, a motor control unit 100A and an instrument panel (commonly referred to as a display console) 108A Mistake. The engine control unit 100A is electric with a board battery 101 via an output contact 102 of the power supply relay 102 connected. The power supply relay 102 closes the output contact 102 of the normally closed type and an exciting coil 102b Powered by a power supply control circuit 121 in the engine control unit 100A to be excited to thereby the output contact 102 close.

A power switch 103 is with the onboard battery 101 and the engine control unit 100A connected and cooperates with the power supply circuit 120 to the power supply relay 102 pretension when the power switch 103 is operated to close. A variable resistor 105a , which forms a fuel level sensor, is connected to the engine control unit 100A connected and talking on a float 105b at. The swimmer 105b Floats on the fuel liquid level (corresponding to the amount of residual fuel) in the fuel tank (not shown) and the resistance value of the variable resistor 105a changes in connection with the position of the swimmer 105b ,

Also are an analog sensor group 104 , a switching sensor group 106 and an electric load group 107 in addition to the display console 108A electrically with the engine control unit 100A connected. Furthermore, if necessary, an external tool 109 with the engine control unit 100A be separably connected.

The display console 108A has a second microprocessor (SCPU) 81 , a second program memory (ROM) 82A , a remaining fuel quantity indicator 83 , a fuel reduction progress message display 84 , a limit alarm indicator 85 and an abnormality detector 86 ,

The engine control unit 100A is provided with a resistance value measuring section which is the resistance value of the variable resistor 105a measures, whereby the residual fuel amount of the thus measured by the resistance value measuring section resistance value of the variable resistor 105a is appreciated.

The resistance value measuring section in the engine control unit 100A consists of a measuring current supply circuit in the form of a fixed resistor 129 and a pulse current supply circuit in the form of a transistor 123 for feeding electrical energy into the variable resistor 105a , an A / D converter 114 and a microprocessor 110A in the form of a CPU together. The microprocessor 110A includes a signal generating section and a resistance value calculating section, as described later.

The microprocessor 110A closes a program memory (FMEM) 111A a self-storing a control program constituting at least a read signal generating section and a resistance value calculating section, a RAM memory (RMEM) 112 for computation, a data store (DMEM) 113 , an input terminal in the on / off signals DI from the switching sensor group 106 be retrieved or input, an output terminal, from the drive signals DO to the electric load group 107 and an output terminal that outputs a pulse power supply command DR.

For example, the program memory exists 111A from a non-volatile flash memory and the data memory 113 in the microprocessor 110A consists of a non-volatile memory (eg an EEPROM memory). The fixed resistance forming the measuring current supply circuit 129 serves to supply a measuring current Is from the on-board battery 101 to the variable resistor 105a to calculate the resistance value of it. The transistor constituting the pulse current supply circuit 123 is used for periodically supplying a pulse-like current Ip, which is greater than the measuring current Is, to the variable resistor 105a from the on-board battery 101 with a power supply period Tp such that an increase in the contact resistance of the variable resistor 105a is suppressed.

The A / D converter 114 converts the value of the voltage Vr across the opposite ends of the variable resistor 105a digitally and transmits it to a RAM memory 112 through the microprocessor 110A based on a read-time signal 115a generated by the read signal generating section of the microprocessor 110A is produced.

The read signal generation section of the microprocessor 110A leads the read-time signal 115a a reading period Ts to the A / D converter 114 with a timing except the duration when the transistor 123 (Pulse current supply circuit) supplies the pulse-shaped current Ip.

The resistance value calculating section in the microprocessor 110A calculates the resistance value Rv (= Vr / Is) of the variable resistor 105a based on the ratio of the voltage Vf across the opposite ends of the variable resistor 105a and the measuring current Is, and estimates the amount of residual fuel from the resistance value Rv of the variable resistor 105a ,

The power control device 100A in addition to the above-mentioned power supply control circuit 121 , the A / D converter 114 , the microprocessor 110A , the festival resistance 129 (Measuring current supply circuit) and the transistor 123 (Pulse current supply circuit), a constant voltage power supply circuit 120 on, voltage divider resistors 122a . 122b , a base resistor 124 of the transistor 123 , a driver transistor 125 , an open circuit stabilization resistor 127a and a current limiting resistor 128 of the transistor 123 , a driver resistor 126 and an open circuit stabilization resistor 127a the driver transistor 125 , an input filter circuit 130 having a high frequency component of the voltage Vr across the opposite ends of the variable resistor 105a disconnects, and a series resistor 131 and a smoothing capacitor 132 sharing the input filter circuit 130 form.

The A / D converter 114 includes a first channel CH1 to which a junction potential of the voltage dividing resistors 122a . 122b (the measuring circuit of a power supply voltage Vb) is applied, a second channel CH2 to which the voltage Vr across the opposite ends of the variable resistor 105a through the input filter circuit 130 is applied, and an input terminal to which a detection signal from the analog sensor group 104 is created.

In addition, the A / D converter converts 114 an analog input voltage of a designated channel in response to the read time signal 115a and the channel selection signal 116a that from the microprocessor 110A is input therein and transmits the completed A / D conversion signal 115b and the measured data 116b to the microprocessor 110A ,

The constant voltage power supply circuit 120 forms a control power supply unit for the microprocessor 110A and generates a control voltage Vcc from the power supply voltage Vb of the on-board battery 101 and leads it to the microprocessor 110A to.

The engine control unit constructed as above 100A performs a signal processing for the variable resistor 105a (Fuel level sensor) and gives the remaining fuel amount, etc. indicative signal to the display console 108A out. The residual fuel quantity indicator 83 in the display panel 108A indicates the remaining fuel amount based on the output from the engine control unit 100A out.

The analog sensor group 104 includes various types of sensors for monitoring the operating conditions of the engine, such as an air flow sensor for measuring the intake air amount drawn into an engine, an accelerator pedal position sensor for detecting the accelerator pedal depression amount, a throttle position sensor for detecting the opening degree of a throttle valve, an exhaust gas sensor, a temperature sensor for detecting the Temperature of engine cooling water, etc., and outputs via an interface circuit (not shown), the thus obtained engine operating condition information to the A / D converter 114 that with the microprocessor 110A cooperates.

The variable resistor included in an analog sensor 105a is disposed in a fuel tank (not shown) such that the resistance value of the variable resistor 105a in accordance with the position of the float 105b which floats, increases and decreases at the liquid level of the fuel in the fuel tank, and when the remaining fuel amount decreases, the resistance value of the variable resistor 105a increases, thereby increasing the voltage Vr across the opposite ends thereof.

The switching sensor group 108 includes various types of sensors for monitoring the engine operating condition such as a crank angle sensor for detecting the crank angle or the rotational position of a crankshaft of the engine, a pulse sensor for measuring the vehicle speed, etc., and outputs the engine operating condition information thus obtained in accordance with the ON / OFF operation of the microprocessor 110A via an interface circuit (not shown).

The electric load group 107 includes, for example, electromagnetic coils for driving fuel injection valves, ignition coils of the engine (if the engine type is a gasoline engine), an electric motor for controlling the opening degree of an intake throttle valve, an electric motor for driving an exhaust gas circulation valve, an electromagnetic valve for changing the gear stage of a transmission, etc. and is driven to by the microprocessor 110A via an interface circuit (not shown) supplied electrical energy.

The display console 108A is provided with the above-mentioned various display equipment, etc., and is electrically connected to the microprocessor 110A via a serial interface circuit (not shown) connected such that electrical energy from the on-board battery 101 to the display console 108A is supplied via a second power switch (not shown). In addition, the second microprocessor 81 in the display console 108A is driven to be driven by a second constant-voltage power supply circuit (not shown). For example, there is a second program memory 82A in the display console 108A from a mask ROM, and includes various types of display control programs for controlling the display console 108A , Such control programs include, as a part thereof, a remaining fuel amount conversion section (step 420 ), the Indian 4 will be described later, a progress message determination section (step 421 ), a boundary determination section (step 422 ) and so on.

The external tool 109 is with the microprocessor 110A via a removable connector and a serial interface circuit (both not shown in the drawings) upon delivery, when a delivery inspection is performed, maintenance is performed, or a product inspection is performed.

In the microprocessor 110A in the engine control unit 100A become the program memory 111A , the RAM memory 112 and the data store 113 connected by a bus or a serial link to cooperate with each other.

In the program memory 111A are in addition to an input and output control program called the engine control unit 100A works, other control programs are stored, which has a stable waiting section (step 203 ), a read signal generating section (step 204b ), a resistance value calculating section (step 300 ), an average calculation section (step 304 ), an abnormality determination section (step 307 ), an abnormality notification command section (step 308 ), or an abnormality history storage section (step 311 ), as in 2 and 3 , which will be described later, and various types of control data such as determination thresholds.

The A / D converter 114 in the form of a multi-channel A / D converter, for example, has a 16-channel 10-bit resolution, and converts an analog input voltage Ai of a designated channel into a digital signal in response to the read-time signal 115a and the channel selection signal 116a that from the microprocessor 110A be entered. The A / D converter 114 converts the analog input voltage Ai of the designated channel into a digital value and sends it to the microprocessor 110A as an A / D conversion completion signal 115b and measured data 116b ,

As a result, the microprocessor fetches 110A the digital conversion value of the analog input voltage Ai of the designated channel as measured data 116b in response to the A / D conversion completion signal 115b and writes it to a predetermined address in the RAM 112 ,

The constant-voltage power supply circuit (control power supply unit) 120 in the engine control unit 100A is from the output contact 102 of the power supply relay 102 energized, generates a control voltage Vcc (= 5V) based on the power supply voltage Vb (= 10V-16V DC) of the on-board battery 101 and feeds them to the respective circuit parts including the microprocessor 110A as a stabilized voltage too. The control voltage Vcc is referred to as a reference voltage Vref for the A / D converter 114 used unchanged.

The power supply control circuit 121 in the power control unit 100A is constructed in such a way that when the power switch 103 closed, it is the power supply relay 102 immediately in response, whereas when the power switch 103 is opened (turned off), they are the excitation of the power supply relay 102 cancels after a predetermined delay time. As a result, secure processing of the microprocessor 110A in a delayed interruption period on the opening of the power supply switch 103 executed.

The reference voltage Vref (= Vcc) becomes a reference voltage terminal of the A / D converter 114 and the relationship between the analog input voltage Ai, a digital conversion output Di, the reference voltage Vref and a resolution n in the A / D converter 114 is shown by the following expression (1). Di = (2 n-1 ) × (Ai / Vref) (1)

In the expression (1) above, a constant K represented by ( ^2n-1 ) in the case of a resolution n of 10 becomes: K = 2 ^10-1 = 1023.

The power supply voltage Vb is applied to the voltage dividing resistors 122a . 122b which are connected in series, and a shared voltage from their interconnect point or its junction is in the first channel CH1 of the A / D converter 114 entered.

Note here that the voltage divider ratio of the voltage divider resistors 122a . 122b is set in such a way that an input voltage (divided voltage) of the A / D converter 114 when the power supply voltage Vb is at a maximum equal to the reference voltage Vref (= 5V DC).

The transistor 123 (Pulse current supply circuit) is driven to pass through the base resistor 124 and the driver transistor 125 to conduct and the driver transistor 125 is determined by the pulse power supply command DR of the microprocessor 110A through the driver resistance 126 driven.

The Open Circuit Stabilization Resistor 127a is between a base terminal and an emitter terminal of the transistor 123 connected and similarly is the open circuit stabilization resistance 127b between a base terminal and an emitter terminal of the transistor 125 connected.

When the transistor 123 becomes conductive, is the variable resistance 125a with a board battery 101 over the current limiting resistor 128 connected, so that the relatively large pulse-shaped current Ip of about several 10 mA the variable resistance 105a is supplied.

On the other hand, if the transistor 123 is open, is the variable resistance 105a with the onboard battery 101 over the festival resistance 129 (the measuring current supply circuit) connected such that a relatively small current of about several mA of the variable resistor 105a is supplied.

The variable resistance 105a has one end connected to the ground of the vehicle against reference potential and the other end to the second channel CH2 of the A / D converter 114 over the series resistance 131 in the input filter circuit 130 connected.

In addition, the smoothing capacitor 132 with the connection point between the series resistor 131 and the input terminal of the A / D converter 114 connected.

As a result, the series resistance forms 131 and the smoothing capacitor 132 comprehensive input filter circuit 130 a low-pass filter for suppressing a noise voltage different from the variable resistor 105a to the second channel CH2 of the A / D converter 114 extending signal wiring is superimposed.

Reference will now be made to the schematic operation of the remaining vehicle fuel amount detecting device according to the first embodiment of the present invention as shown in FIG 1 is constructed.

First of all, when the power switch 103 is closed, also the output contact 102 of the power supply relay 102 closed and the constant voltage supply circuit 120 gets from the onboard battery 101 energized, thereby producing the stabilized control voltage Vcc, followed by the microprocessor 110A the operation begins. The microprocessor 110A drives the electric load group 107 and controls it in response to the voltage level of a respective analog signal from the analog sensor group 104 is received, the operating state of a respective ON / OFF signal Di, that of the switching sensor group 106 is received, and the input and output control program stored in the program memory 111A is stored.

Next, reference will be made to the calculation processing of the resistance value of the variable resistor 105a (Fuel level sensor) in accordance with the microprocessor 110A while referring to an in 2 and 3 shown flow chart.

2 shows a first half of the operation of the microprocessor 110A and 3 shows a second half of the operation thereof, the processing flow of the 2 and 3 is continuously performed by a node A.

In 2 makes step 203 the stability wait section and step 204b forms the reading signal generation section. Also forms in 3 step 300 the resistance value calculating section and step 304 forms the average calculation section. In addition, step forms 307 the abnormality detecting section and step 308 forms the abnormality notification command section and step 311 forms the abnormality history storage section.

First of all, in 2 the microprocessor 110A activated to start the sensor input processing at every predetermined period or every predetermined cycle (eg, an average period of about 10 ms) (step 200 ). Note here that if the activation interval of the starting step 200 for example, exceeds 20 ms, a watchdog timer (not shown) is operated to initialize and reactivate the microprocessor 110A ,

Consequently, depending on whether the number of execution operations of the in 2 and 3 determines whether it is a pulse energy supply execution time (a supply time of excessive energy) to which the pulse-like current Ip corresponds to the variable resistance 105a is fed (step 201 ) and if it is determined that the frequency with which the step 201 is not reached 5 times (ie, NO), the control flow immediately goes to the step (to be described later) 204a ,

On the other hand, if in step 201 it is determined that the frequency with which the step 201 5 times (ie, YES), a pulse energy supply command DR of a predetermined pulse width (eg, several ms) is generated (step 202 ).

Note here that in the step 201 by running the in 2 and 3 control sequence is determined once a "YES" is determined each time the frequency with which the step 201 has been passed, for example, reached 5 times, and the control process goes to step 202 whereas a determination of "NO" is made the other 4 times and the control flow goes to step 204a goes.

When the pulse-like power supply command DR becomes a high logic level in step 202 reached ("H"), the driver transistor 125 and the transistor 123 be closed or turned on, so that the pulse-like current Ip the variable resistor 105a through the current limiting resistor 128 is supplied.

As a result, when the pulse-like power supply (the supply of the pulse-shaped current Ip) becomes the variable resistor 105a in step 202 has been completed or completed, waiting processing of a few ms (stopping the excessive power supply and waiting for stability) is executed by the stability waiting section (step 203 ) to the charged voltage of the smoothing capacitor 132 , which has increased rapidly, is returned to normal levels.

Then, the first channel CH1 becomes the A / D converter 114 with the help of the channel selection signal 116a designated and a reading time signal 115a is generated to provide an instruction for performing the digital conversion of the divided voltage (proportional to the power supply voltage Vb) input to the first channel CH1 (step 204a ).

Note here that the time the A / D converter 114 to perform the digital conversion of an input signal, is only a small or infinitely short time, in the control of the 2 and 3 can be neglected.

It is then determined whether an A / D conversion completion signal 115b from the A / D converter 114 has been received (step 205a ) and if it is determined that the signal 115b has not been received (ie, YES), a return instruction is executed to step 205a where the reception of the A / D conversion signal 115b is waited.

On the other hand, if in step 215a it is determined that an A / D conversion completion signal 115b is received (ie, YES), the digitally converted value of the divided voltage, which is input to the first channel CH1, in the first address of the RAM memory 112 saved (step 206a ).

Then the second channel CH2 becomes the A / D converter 114 with the help of the channel selection signal 116a designated and a reading time signal 115a is generated to provide an instruction to perform the digital conversion of the value of the voltage Vr across the opposite ends of the variable resistor 105a which is input to the second channel CH2 (step 204b ).

Subsequently, it is determined whether an A / D conversion completion signal 115b from the A / D converter 114 has been received (step 205b ), and if it is determined that the signal 115b has not been received (ie, NO), a return instruction goes to step 205b where the reception of an A / D conversion completion signal 115b is waited.

On the other hand, if in step 205b it is determined that an A / D conversion completion signal 115b is received (ie, YES), the digitally converted value of the voltage proportional to the voltage Vr across the opposite ends of the variable resistor 105a is input to the second channel CH2 in the second address of the RAM 112 saved (step 206b ) and the control flow goes on to the in 3 shown by the node A.

Note here that when the voltage Vr across the opposite ends of the variable resistor 105a in step 205b is read, the measuring current Is, the variable resistance 105a is supplied by an on-board battery 101 through the output contact 102 and the festival resistance 129 flows.

The step 206b in 2 Subsequently, the resistance value Rv of the variable resistor becomes 105a in the following manner by the resistance value calculating section in FIG 3 calculated (step 300 ).

First, the measurement current Is is calculated in accordance with the following expression (2) Is = (Vb-Vr) / Rs (2) wherein the power supply voltage Vb is a value obtained by dividing the value proportional to the power supply voltage Vb obtained in the step 206a is read out by a proportional coefficient, and the voltage Vr across the opposite ends of the variable resistor 105a is the value in the step 206b is read out, and the resistance Rs of the fixed resistor 129 is a control constant in advance in the program memory 111A is stored.

Hereinafter, the resistance value Rv is calculated using the voltage Vr across the opposite ends of the variable resistor 105a and the measuring current Is calculated as shown in the following expression (3). Resistance Rv = Vr / Is = Rs × Vr / (Vb-Vr) (3)

Thereupon it is determined whether in the step 300 calculated resistance value Rv is within a normal band range between the predetermined upper and lower limits (step 301 and when it is determined that the resistance value Rv is out of the normal band (ie, NO), the control flow goes to step 305 (to be described later).

Note here that the upper and lower limits are in the form of determination thresholds in advance in the program memory 111A are stored.

On the other hand, if in step 301 is determined that the calculated resistance value Rv is within the normal band or range (ie, YES), the current value of the abnormality calculation counter, the in the following step 306a or 306b is counted, reset (step 302 ) and the resistance value Rv determined to be normal is stored in a data table provided by the RAM memory 112 is formed (step 303 ).

Note here that the data table of the RAM memory 112 is a FIFO table with a data output in the order of input, in which resistance value data is stored at a plurality of points, and the oldest data is discarded and the last data is stored when the data table has been filled up.

Subsequently, an average value of the resistance value Rv sequentially stored in the data table in step 303 has been stored by the average calculating section (step 304 ) and the control flow goes to step 309 ,

Note here that the average calculation section is in the form of the step 304 calculates the average value using any statistical method, eg calculating a moving average by dividing the sum of the resistance values Rv at the plurality of points sequentially stored and discarded from the data table by the number of dots to be added or an average value by Dividing the sum of a maximum resistance value and a minimum resistance value by 2, or an average value of the amplitude of the pulsation for the vibration or variation of the liquid level of fuel according to the vibration of the vehicle body, and then sends the thus-calculated average value to the display panel 108A via the serial communication line.

On the other hand, when the resistance value Rv is out of the normal band, the control flow goes from step 301 to step 305 where it is determined if the step 300 calculated resistance Rv is excessively large or small.

When in step 305 is determined that the resistance value Rv is excessively large (ie, YES), it is assumed that a contact resistance of the variable resistor 105a or there is an "open circuit or break" of the signal line, or there is a "power supply fault" in which the signal wiring is shorted to a power supply line, and a first fault counter for counting open circuits and power supply errors is incremented (ie, "1" becomes Instantaneous value added) (step 306a ).

On the other hand, if in step 305 is determined that the resistance value Rv is excessively small (ie, NO), it is assumed that there is a ground fault in which a signal wiring short to ground has occurred and a second error counter for counting ground errors is incremented (ie, "1" becomes added to the moment value) (step 306b ).

Although in step 305 it has been determined whether the resistance value Rv of the variable resistor 105a is excessively large or small in the case of the contact failure of the variable resistor 105a or the open circuit, the power supply error or the ground fault of the signal wiring, it may be determined whether the voltage Vr across the opposite ends of the variable resistor article 105a is overly large or small.

In the following step 306a or 306b is determined by the abnormality determination section (step 307 ) makes a determination as to whether the current count value (the number of abnormality occurrence) of the first or second error counter is excessively large (exceeds a predetermined value) or not (less than or equal to the predetermined value).

When in step 307 it is determined that the number of occurrences of abnormality is excessively large (ie, YES), an abnormality notification command is issued by the abnormality notification command section (step 308 ) and to the display console 108A sent via the serial communication line and the control flow goes to step 309 whereas when in step 307 it is determined that the number of occurrences of abnormality is less than or equal to the predetermined value (ie, NO), the control flow immediately to step 309 continues.

In step 309 , the steps 304 . 308 follows or is executed when in step 307 "NO" is determined based on the open / closed state of the power switch 103 determines whether it is a backup time of abnormality or error information (opened).

When in step 309 it is determined that the energy switch 103 is closed (ie, on) (ie, NO), the control flow goes immediately to an operation end step 310 in which the processing routine of 2 and 3 is ended. After finishing the step 310 the control flow gets an operation wait state during the microprocessor 110A performs other control operations and after a predetermined time (eg, about 10 ms in the average duration) elapses, the operation start step 200 of the 2 activated again.

On the other hand, if in step 309 it is determined that the energy switch 103 is open (switched off) (ie, YES), by the power supply relay 102 carried out a self-hold power supply, so that an abnormality or error information to the non-volatile data memory 113 is transmitted and stored by the abnormality history storage section (step 311 ).

Note here that to the data store 113 in step 311 transmitted various learning information, abnormality occurrence history information, etc. in the engine control unit 100A lock in.

If the backup processing is in accordance with step 311 is completed, the microprocessor stops 110A following its operation by itself (step 312 ). As a result, the self-holding operation of the power supply relay becomes 102 by the power supply control circuit 121 released and the excitation of the power supply relay 102 is canceled for interrupting or disconnecting the power supply (step 313 ).

Now, reference will be made to the operation of the second microprocessor 181 in the display console 108A while on the flowchart of the 4 Reference is made.

In 4 makes step 420 a remaining fuel amount conversion section and step 421 forms a progress message determination section and 422 forms a boundary determination section.

The second microprocessor 81 in the display console 108A First, the display control of the residual fuel quantity relationship starts (step 400 ) and observes the operating state of a reception flag representing whether a serial / parallel converter (not shown) transmits serial communication data from the engine control unit 100A so that it determines if there is receive data (step 401 ).

When in step 401 it is determined that the reception flag has been cleared to "0" (ie, NO), it is assumed that there is no new reception data, and the control immediately goes to the end processing of the display control operation (step 410 ), whereas if in step 201 it is determined that the reception flag is operated (ie, set to "1") and, accordingly, there is reception data (ie, YES), the reception data is read out (step 402 ) and it is determined whether the reception data thus read out are the average value data obtained in the above-mentioned step 304 have been sent (step 403 ).

When in step 403 it is determined that the received data is not the average value data (ie, NO), it is subsequently determined whether the read out received data is the abnormality notification command mentioned in the above-mentioned step 308 has been sent (step 404 ).

When in step 404 it is determined that the reception data is not the abnormality notification command (ie, NO), it is assumed that the reception data is unassigned data, and the control flow goes to the operation end step 410 whereas when in step 404 It is determined that the reception data is the abnormality notification command (ie, YES), an abnormality notification command for the abnormality detector 86 is generated (step 405 ) and the control flow proceeds to the operation end step 410 ,

If, on the other hand, in step 403 it is determined that the read-out data is the average value data (ie, YES), the present value of the residual fuel is converted by converting by the remaining fuel amount conversion section (step 420 ) is calculated based on the average resistance value R0 obtained in step 402 has been read out, and a conversion equation or a data table of a resistance value to the residual fuel quantity characteristic, which in advance in the second program memory 82A are stored.

At this time, the in step 420 converted residual fuel amount information on the remaining fuel amount indication 83 displayed.

Subsequently, by making a comparison between the average resistance value R0 obtained in step 402 has been read out, and an average message start resistance which is in advance in the second program memory 82A has been stored, a determination made by the progress message determination section (step 421 ), whether it is a progress message start time (average resistance value R0> progress message start resistance value) to notify the reduced state of the amount of remaining fuel.

When in step 421 it is determined that the average resistance value R0 is less than or equal to the progress message start resistance value, and thus the remaining fuel amount reduction progress message start time is not reached (ie, NO), the control flow goes to the operation end step 410 whereas if in step 421 it is determined that the average resistance value R0 is greater than the average message start resistance value and, accordingly, that the remaining fuel amount reduction progress message start time is present (ie, YES) by making a comparison between the average resistance value R0 obtained in step S4 402 is read out, and a limit resistance value (> average message start resistance value), which is in advance in the second program memory 82A Subsequently, a determination is made by the boundary determination section (step 422 ), whether it is a limit alarm start time (average resistance value R0> limit resistance value) to notify the limit state of the amount of remaining fuel.

When in step 422 it is determined that the average resistance value R0 is less than or equal to the limit resistance value and therefore no limit alarm start time (ie, NO), it is assumed that the amount of remaining fuel is at an average message start level and an average message display command is generated to operate the fuel cut progress message display 84 (Step 423 ) and then the control flow goes to the operation end step 410 ,

On the other hand, if in step 422 it is determined that the average resistance value R0 is greater than the limit resistance value, and that it is therefore the limit alarm start time (ie, YES), an alarm indication command is generated to operate the limit alarm indication 85 (Step 424 ) and the control flow goes to the operation end step 410 ,

In the operation end step 410 Wait processing is executed for a predetermined period while the second microprocessor is executing 81 other display control programs. After the predetermined period of time has elapsed, the operation start step 400 activated again.

As described above, a vehicle remaining fuel quantity detecting means 10A according to the first embodiment of the present invention with the variable resistor 105a provided the position of floating on the fuel liquid level float 105b is assigned, and the resistance value measuring section, the resistance value Rv of the variable resistor 105a is measured, wherein the residual fuel amount is estimated and is indicated by the measured resistance value Rv of the variable resistor 105a ,

The resistance value measuring section in the vehicle remaining fuel amount detecting means 10A consists of the measuring current supply circuit (fixed resistor 129 ) and the pulse current supply circuit (transistor 123 ) for supplying electric power to the variable resistor 105a , the A / D converter 114 and the microprocessor 110A ,

The microprocessor 110A used in program memory 111A together with the RAM memory 112 and control programs that function at least as the read signal generating section and the resistance value calculating section are in the program memory 111A saved.

The measuring current supply circuit (fixed resistor 129 ) forms the power supply circuit, which is for supplying the measuring current Is from the on-board battery 101 to the variable resistor 105a serves to calculate the resistance Rv thereof.

The pulse current supply circuit (transistor 123 ), the power supply circuit serving to periodically supply the pulse-shaped current Ip which is larger than the measurement current Is to the variable resistor 105a from the on-board battery 101 with the power supply period Tp, an increase in the contact resistance of the variable resistor 105a to suppress.

The A / D converter 114 converts the value of the voltage Vr across the opposite ends of the variable resistor 105a digitally and the digital conversion data thus obtained become the RAM memory 112 via the microprocessor 110A based on the read-time signal 115A transmitted by the read signal generating section (step 204b ).

The read signal generation section (step 204b ) forms a portion which is for supplying the read timing signal 115a the reading period Ts to the A / D converter 114 with the timing is used except the period when the pulse current supply circuit (transistor 123 ) supplies the pulsed current Ip.

The resistance value calculating section (step 300 ) consists of a section that calculates the resistance value Rv (= Vr / Is) of the variable resistor 105a based on the ratio of the voltage Vr across the opposite ends of the variable resistor 105a and the supplied measuring current Is, and estimating the residual fuel amount from the resistance value Rv of the variable resistor 105a ,

The average value of the generation period (power supply period Tp) of the pulse-shaped current Ip generated by the pulse current supply circuit (transistor 123 ), a time interval larger than the average value of the generation period (read period Ts) of the read time signal becomes 115a generated by the read signal generation section (step 204b ).

Accordingly, the pulse current Ip is not always supplied when the voltage Vr across the opposite ends of the variable resistor 105a is measured, so that even if the supplied pulse-shaped current Ip is set to a large value, the generation of heat of the pulse current supply circuit (transistor 123 ), thereby enabling the motor control circuit 100A to build with a small size and at low cost.

The resistance value measuring section in the vehicle remaining fuel amount detecting means 10A is further connected to the input filter circuit 130 and the stability wait section (step 203 ) and the input filter circuit 130 forms the low-pass filter for suppressing the high-frequency noise voltage, which is between the variable resistor 105a and the analog input terminal of the A / D converter 114 is supplied (second channel CH2).

The stability wait section (step 203 ) forms a portion which waits for a period of time during which the output voltage of the input filter circuit 130 in a predetermined time after the pulse current supply circuit (transistor 123 ) supplies the pulsed current Ip, attenuates.

The read signal generation section (step 204b ) forms a portion which is for supplying the read timing signal 115a the reading period Ts of the A / D converter 114 is used with a timing except one time period in which the pulse current supply circuit (transistor 123 ) supplies the pulse-shaped current Ip and a waiting period of the stability waiting section. Accordingly, no abnormal A / D conversion output resulting from a noise voltage superimposed on a detection signal which is the resistance value Rv of the variable resistor is generated 105a and, moreover, the AD conversion processing is not performed in a damping period after the supply of the pulse-shaped current Ip is stopped, so that it becomes possible to obtain a high-precision A / D conversion output.

In addition, the program memory closes 111A in the microprocessor 110A a control program that sets the abnormality determination section (step 307 ) and a control program constituting the abnormality history storage section (step 311 ).

The abnormality detecting section (step 307 Finally, an abnormality determination is made when the result of determining the at least the voltage Vr across the opposite ends of the variable resistor 105a or the resistance Rv of the variable resistor 105a calculated by the resistance value calculating section (step 300 ) is excessively large or excessively small while continuously rejecting (at a predetermined frequency) from the predetermined normal range over a predetermined period of time. That is, the abnormality determination section (step 307 ) forms a section which ultimately decides the abnormality occurrence state and generates an abnormality message by means of the abnormality notification command section (step 308 ) when the result of a determination such as a contact failure of the variable resistor 105a , an open circuit fault of Circuit wiring showing the variable resistor 105a and the A / D converter 114 connects, a power supply error in which the signal wiring and the power supply line are short-circuited to each other, a ground fault, in which the signal wiring is shorted to ground or the like is continued.

Further, the abnormality history storage section (step 311 ) A section for transmitting the fact that the abnormality determination section (step 307 ) has determined the state of occurrence of an abnormality to the nonvolatile data memory 113 and for storing in it. Accordingly, it is possible to prevent the generation of a groundless abnormality message, and once an abnormality notification has been made, it is saved as abnormality history information, and thus it can be used as reference information for maintenance and inspection.

The program memory 111A further includes a control program that includes the averaging section (step 304 ) and the average calculation section (step 304 ) forms a section that averages processing to the resistance value Rv of the variable resistor 105a applied by the resistance value calculating section (step 300 and calculates the average resistance value R0 which is the statistical value of either a moving average of the last calculated values at a predetermined number of points, or an arithmetic average of a maximum value and a minimum value {ie; a maximum value + a minimum value) / 2}, or an average of the pulse amplitude. Accordingly, even if the position of the float 105b is caused to vary in a slight way due to the oscillation or fluctuation of the liquid level, it is possible to measure an average of the resistance value Rv.

The measuring current supply circuit consists of the fixed resistor 129 a known resistance value, in series with the variable resistor 105a is connected and by connecting the series circuit, which is the variable resistor 105a and the festival resistance 129 includes, with the on-board battery 101 , which supplies the measurement current Is (= Vb-Vr) / Rs) based on the relationship between the power supply voltage Vb of the on-board battery 101 , the voltage Vr across the opposite ends of the variable resistor 105a and the resistance value Rs of the fixed resistor 129 ,

The respective values of the power supply voltage Vb of the on-board battery 101 and the voltage Vr (= Rv × Is) across the opposite ends of the variable resistor 105a be in the RAM memory 112 through the A / D converter 114 and the microprocessor 110A and the resistance value calculating section (step 300 ) forms a portion that is to calculate the resistance value Rv (= Vr / Is = Rv × Is / (Vb-Vr)) based on the ratio of the voltage Vr across the opposite ends of the variable resistor 105a and the supplied measuring current Is is used. Accordingly, the measurement current Is can be obtained by the simple configuration of the power supply circuit.

In addition, the value of the measuring current Is is smaller than that of the pulse-shaped current Ip, so that the power consumption of the fixed resistor 129 can be reduced or suppressed and therefore a low-cost resistor of small size and high precision as a fixed resistor 129 can be used.

There is also the microprocessor 110A an engine control microprocessor having at least one fuel injection control function in addition to a remaining fuel amount detection function and the second microprocessor 81 that the display console 108A controls is with the microprocessor 110A connected via the serial communication line. The engine control microprocessor 110A sends the average resistance R0 of the variable resistor 105a indicated by the averaging section (step 304 ) has been calculated and at least by the abnormality detection section (step 307 ) generate an abnormality notification command to the second microprocessor 81 in the display console 108A through the serial signal communication line.

The display console 108A excludes at least the abnormality detector 86 to report an abnormality or fault alarm issued by the microprocessor 110A is generated, in addition to the remaining fuel quantity display 83 and at least one of a remaining fuel amount reduction progress message indication 84 and the limit alarm indicator 85 ,

The second microprocessor 81 in the display console 108A cooperates with the second program memory 82A by storing a control program that functions as a remaining fuel amount conversion section (step 420 ) and at least one progress message detecting section (step 421 ) and the boundary detection section (step 422 ). The remaining fuel amount conversion section (step 420 ) forms a portion that serves to calculate the residual fuel by converting the amount of current based on the average resistance value R0 derived from the serial communication line, and the conversion equation or the data table of the resistance value against the remaining fuel amount characteristic obtained in advance in the second program memory 82A are stored. The progress message detection section (step 421 ) and the boundary determination section (step 422 ) collectively form a portion having the average resistance value R0 received from the serial communication line with the progress message resistance value and the limit resistance value stored in advance in the second program memory 82A is stored, compares, and generates a remaining fuel amount reduction progress message display command and a limit alarm indication command.

Thus, the average resistance R0 of the variable resistor becomes 105a for detecting the residual fuel amount by the engine control unit 100A and the average resistance value R0 thus calculated becomes the display panel 108A sent by serial transmission. As a result, the control load of the second microprocessor 81 in the display console 108A be reduced.

Note here that the serial communication line between the engine control unit 100A and the display console 108A connects, originally or basically, to sending a plurality of types of abnormality notification commands to the engine control unit 100A is provided so that no additional hardware is required.

In addition, in order to confirm the validity of a fluctuation characteristic between the accumulated amount of injected fuel and the amount of residual fuel, gas leakage from the plastic tank, etc., the engine control unit 100A use the residual fuel amount information to compare the tank internal volume with the tank internal pressure.

Embodiment 2.

Although in the above-mentioned first embodiment ( 1 ) the measuring current supply circuit and the pulse current supply circuit for the variable resistor 105a from the fixed resistor 129 or the transistor 123 They can also be formed from a constant current circuit 140 and a transistor (constant switching circuit) 147 be formed as in 5 shown.

Hereinafter, reference will be made to a vehicle remaining fuel quantity detecting means 10B according to a second embodiment of the present invention while referring to a circuit block diagram of 5 , the 1 equivalent.

In represent individual figures the same reference numerals identical or corresponding parts, however is "B" after each reference with respect to those parts of this second embodiment added partially from the corresponding one of the first mentioned above embodiment differ.

In 5 is the vehicle remaining fuel amount detecting means 10B primarily with a variable resistor 105a provided for the fuel level detection, a motor control unit 100B and a display console 108B ,

In a similar manner as set forth above, a microprocessor cooperates 110B in the engine control unit 100B with a program memory 111B , and a second microprocessor 81 in the display console 108B cooperates with a second program memory 82B , In addition, the engine control unit 100B is configured to perform signal processing of a fuel level sensor and display information after the determination of the remaining fuel, a progress message of the reduction of residual fuel, and an alarm timing to the display console 108B sends.

Here is the following description mainly regarding differences between 5 and 1 performed.

In 5 The configurations of the measuring current supply circuit and the pulse current supply circuit for the variable resistor differ 105a , the program memory 111B in the microprocessor 110B and the second program memory 82B in the display console 108B partly in the function of those in the above-mentioned first embodiment.

Specifically, the measurement current supply circuit and the variable resistance pulse current supply circuit 105a through the constant current circuit 140 formed, to which the transistor 147 which functions as a constant switching circuit.

The constant current circuit 140 includes a transistor 142 for feeding energy to the variable resistor 105a , a pair of emitter resistors 141 . 141b (a measuring current supply circuit and a pulse power supply circuit) for the transistor 142 . 141b , a driver resistor 143 for the transistor 142 , a transistor 144 connected to a base terminal of the transistor 142 is connected, and an emitter resistor 145 and a driver resistor 156 of the transistor 144 ,

The emitter resistor 141 is with the onboard battery 101 through an output contact 102 connected and functions as a measuring current supply circuit for the variable resistor 105a , Also, the emitter resistance 141b with the onboard battery 101 through the transistor 147 and the output contact 102 and functions as a pulse power supply circuit for the variable resistor 105a ,

The drive resistance 143 of the transistor 142 is between a positive potential-side connection of the emitter resistor (measuring current supply circuit) 141 and the base terminal of the transistor 142 so inserted that energy through the transistor 144 and the emitter resistor 145 is supplied. The driver resistance 146 of the transistor 144 is between a base terminal of the transistor 144 and ground is inserted and a control voltage Vcc is applied to the driver transistor 146 created. The transistors 144 . 142 together form an emitter follower circuit (constant current supply circuit) for supplying a constant measuring current Is to the variable resistor 105a ,

Here it is assumed that the individual resistance values of the emitter resistor 141 , the driver resistance 143 and the emitter resistance 145 R141a, R143 and R145 are and that individual voltages between the emitter and base terminals of the transistors 41 . 44 ΔVbe2 and ΔVbe4 respectively, a voltage V143 connected to the drive resistor 143 is applied is calculated as shown by the following expression (4), and thus becomes the variable resistance 105a supplied measuring current Is represented by the following expression (5). V143 = R143 × (Vcc-ΔVbe4) / R145 (4) = Is = (V143 - ΔVbe2) / R141a (5)

In the expressions (4) and (5) above, the emitter-base voltages ΔVbe2, ΔVbe4 are substantially prescribed minute values, so that when these minute voltages are ignored for the sake of convenience, the measurement current Is is approximately calculated by the following expression (6). Is ≈Vcc × (R143 / R145) / R141a (6)

The transistor (constant switching circuit) 147 has an emitter terminal with the output contact 102 connected, a collector terminal with the emitter resistor 141b of the transistor 142 connected and a base terminal to a ground circuit via the base resistor 124 and the driver transistor 125 connected. Accordingly, the driver transistor 125 by a pulse energy supply command DR of the microprocessor 110B via the driver resistor 126 driven to lead.

As a result, the transistor becomes 147 driven to be responsive to through the microprocessor 110B to generate generated pulse power supply command DR, whereby the emitter resistor (pulse power supply supply circuit) 141b parallel to the emitter resistor 141 (Measuring current supply circuit) is connected.

When the transistor 147 is closed or turned on, the resistance value R141a in the expression (6) above decreases so that a pulse-shaped current Ip represented by the following expression (7) becomes the variable resistance (fuel level sensor) 105a is supplied. Ip ≈ Vcc × (R143 / R145) / (R141a || R141b) (7) where (R141a || R141b) is a parallel-connected resistance value of the emitter resistor 141 and the emitter resistance 141b is.

Now, reference will be made to the schematic operation of the remaining vehicle fuel amount detecting means 10B according to the second embodiment of the present invention, as in 5 shown.

First of all, similar to what has been stated above, the closing of a power switch 103 towards the output contact 102 of the power supply relay 102 also closed and a constant voltage power supply circuit 120 gets from the onboard battery 101 energized, thereby producing the stabilized control voltage Vcc as a result of which the microprocessor 110B the operation begins. The microprocessor 110B drives an electric load group 107 and controls it in response to the voltage level of each of the analog sensor group 104 received analog signals, the operating state of each of a switching sensor group 106 received ON / OFF signals DI and an input and output control program stored in the program memory 111B is stored. Next, reference will be made to the calculation processing of the resistance value of the variable resistor (fuel level sensor). 105a in accordance with the microprocessor 110B while reference is made to a flow chart as shown in FIG 6 and 7 is shown.

6 shows a first half of the operation of the microprocessor 110B and 7 shows a second half of the operation thereof, the processing flow of the 6 and 7 is continuously performed by a node B.

In 6 correspond to steps 600 to 603 the above steps 200 to 203 ( 2 ) and steps 604 to 606 correspond to the above-mentioned steps 204b to 206b ( 2 ). Also correspond to steps 700 to 713 in 7 the above steps 300 to 313 ( 3 ) and steps 720 to 724 correspond to the above-mentioned steps 420 to 424 ( 4 ).

First of all, in 6 the microprocessor 110B activated to start the sensor input processing every predetermined period or each predetermined cycle (eg, an average period of about 10 ms (step 600 ). Note here that if the activation interval of the starting step 600 for example, exceeds 20 ms, a watchdog timer (not shown) is operated to initialize and reactivate the microprocessor 110B ,

Subsequently, depending on whether the number of executions of the in 6 and 7 5) determines whether there is a pulse power supply execution time (time of excessive power supply) at which the pulse-shaped current Ip corresponds to the variable resistor 105a is fed (step 601 ), and if it is determined that the frequency with which the step 601 is passed 5 times (ie, NO), the control flow goes immediately to step 604a (to be described later).

On the other hand, if in step 601 it is determined that the frequency with which the step 601 5 is reached (ie, YES), a pulse energy supply command DR of a predetermined pulse width (eg, several milliseconds) is generated (step 602 ). Note here that in the step 601 by running the in 6 and 7 Control flow shown a determination of "YES" once every 5 times, if the frequency with which the step 601 is passed through, for example, 5 is reached, and the control process to step 602 changes, while determining "NO" the others are made 4 times and the control flow goes to step 604a replaced.

When the pulse power supply command DR becomes a high logic level ("H") in step 602 gets, become the driver transistor 125 and the transistor 127 closed or turned on, so that the pulse-shaped current Ip represented by the above-mentioned expression (7) corresponds to the variable resistance 105a is supplied.

Then, when the pulse energy supply (the supply of the pulse-shaped current Ip) becomes the variable resistor 105a in step 602 has been completed or completed, the wait processing of a few ms (stop the supply of excessive energy and wait for stability) performed by the stability waiting section (step 603 ) until the charged voltage of a smoothing capacitor 132 , which has increased rapidly, has returned to normal levels.

Then, a second channel CH2 for an A / D converter 114 with the help of a channel selection signal 116a designated and a reading time signal 115a is generated to provide an instruction to perform the digital conversion of the value of the voltage Vr across the opposite ends of the variable resistor 105a which is input to the second channel CH2 (step 604 ).

It is then determined whether an A / D conversion completion signal 115b from the A / D converter 114 has been received (step 605 and when it is determined that an A / D conversion completion signal 115b has not been received (ie, NO), a back command is executed to step 605 at which the reception of the A / D conversion completion signal 115b is waited.

On the other hand, if in step 605 it is determined that an A / D conversion completion signal 115b (ie, YES), the digitally converted value of a voltage becomes proportional to the voltage Vr across the opposite ends of the variable resistor 105a which is input to the second channel CH2 in the second address of the RAM 112 saved (step 606 ) and the control flow goes on to the in 7 shown by node B. Note here that when the voltage Vr across the opposite ends of the variable resistor 105a in step 606 is read, the variable resistance 105a supplied measuring current Is becomes a constant current as shown by the above-mentioned expression (6).

The step 606 in 6 Subsequently, the resistance value Rv of the variable resistor becomes 105a in the following manner by a resistance value calculating section in FIG 7 calculated (step 700 ) as shown by the following expression (8). Rv = Vr / Is (8) wherein the voltage Vr across the opposite ends of the variable resistor 105a the one in the step 606 read value is and the value of the measuring current Is is a control constant, in advance in the program memory 111B is stored.

Subsequently, it is determined whether or not the resistance value Rv, which in step 700 is within a normal band between the predetermined upper and lower limits (step 701 ) and if it is determined that the Wi If Rv is outside the normal band (ie, NO), the control flow goes to step 705 (to be described later). Note here that the upper and lower limits are in the form of determination thresholds in advance in program memory 111B are stored.

On the other hand, if in step 701 is determined that the calculated resistance value Rv is within the normal band or range (ie, YES), the instantaneous values of the in the following steps 706a and 706b counted abnormality calculation counter is reset (step 702 ) and the resistance value Rv determined to be normal is stored in a data table provided by the RAM memory 112 is formed (step 703 ). Note here that the data table of the RAM memory 112 is a FIFO table in which resistance value data is stored at a plurality of points and the oldest data value is discarded and the last data value is stored when the data table has been filled up.

Subsequently, a in the data table in step 703 sequentially stored average value of the resistance value Rv is calculated by an average calculating section (step 704 ) and the control flow goes to step 720 , Note here that the average calculating section in the form of the step 704 calculates the average value using any statistical method, eg, a moving average by dividing the sum of the resistance values Rv at the plurality of dots stored and discarded sequentially in the data table by the number of points to be added, or an average value by dividing the sum of a maximum resistance value and a minimum resistance value by two, or an average value of the amplitude of the pulses for oscillation or variation of the liquid level of the fuel according to the vibration of the vehicle body.

On the other hand, when the resistance value Rv is out of the normal band, the control flow changes from the step 701 to the step 705 , where it is determined whether the resistance Rv, in step 700 has been calculated to be excessively large or small.

When in step 705 is determined that the resistance value Rv is excessively large (ie, YES), it is assumed that a contact resistance of the variable resistor 105a or an "open circuit or interruption" of the signal wiring or a "power supply error" in which a short circuit of the signal wiring to a power supply line has occurred, and a first error counter for counting open circuit and power supply errors is incremented (ie, "1" becomes Instantaneous value added) (step 706a ).

On the other hand, if in step 705 is determined that the resistance Rv is excessively small (ie, NO), it is assumed that there is a ground fault in which a short circuit of the signal wiring to ground has occurred, and a second error counter for counting ground faults is incremented (ie, "1 "is added to the current value) (step 706b ).

Although in step 705 a determination is made as to whether the resistance value Rv of the variable resistor 105a is excessively large or small, may be in the case of the contact resistance of the variable resistor 105a or the open circuit, the power supply error or the ground fault of the signal wiring, whether the voltage Vr across the opposite ends of the variable resistor 105a is overly large or small.

step 706a or 706b Subsequently, a determination is made by an abnormality detecting section (step 707 ) Whether or not the current count value (the number of occurrences of abnormality) of the first or second error counter is excessively large (exceeds a predetermined value) or not (less than or equal to the predetermined value).

When in step 707 it is determined that the number of occurrences of abnormality is excessively large (ie, YES), an abnormality notification command is generated by the abnormality notification command section (step 708 ) and to a display console 108B sent over a serial communication line, and the control flow goes to step 709 whereas when in step 707 it is determined that the number of occurrences of abnormality is less than or equal to the predetermined value (ie, NO), the control flow immediately advances to step 709 ,

Following the above mentioned step 704 For example, the torque amount of the residual fuel is calculated by a remaining fuel amount conversion section (step 720 ) based on the calculated value of the average resistance value R0 and a conversion equation or a data table of a resistance value against a remaining fuel quantity characteristic obtained in advance in the program memory 111B are stored. The remaining fuel quantity information, which in step 720 is converted to the display console 108B transmitted via the serial communication line and by a residual fuel quantity indicator 83 displayed.

Subsequently, by making a comparison between the one in step 704 calculated average resistance value R0 and a progress message start resistance value in advance in the program memory 111B has been stored, a determination made by a progress message determination section (step 721 ), whether it is a progress message start time (average resistance value R0> progress message start resistance value) to notify the reduced state of the remaining fuel amount.

When in step 721 it is determined that the average resistance value R0 is less than or equal to the progress message start resistance value, and thus that it is not a progress message start time (ie, NO), the control flow immediately shifts to step 709 whereas when in step 721 it is determined that the average resistance value R0 is greater than the progress message start resistance value, and therefore that it is a remaining fuel amount reduction progress message start time (ie, YES), by making a comparison between the in step 704 calculated average resistance value R0 and one in advance in the program memory 111B stored limit resistance value (> average message start resistance value) subsequently, a determination made by a determination section (step 722 ), whether it is a limit alarm start time (average resistance value R0> limit resistance value) to notify the limit state of the residual fuel amount.

When in step 722 it is determined that the average resistance value R0 is less than or equal to the limit resistance value and that it is therefore no limit alarm start time (ie, NO), it is assumed that the remaining fuel amount is at a progress message start level and a progress message indication command is generated to operate a fuel cut progress notification indication 84 (Step 723 ), and then the control flow goes to step 709 ,

On the other hand, if in step 722 it is determined that the average resistance value R0 is greater than the threshold resistance value, and thus that a limit alarm start time is determined (ie, YES), an alarm indication command is generated to operate a limit alarm indication 85 (Step 724 ) and the control flow goes to step 709 ,

In step 709 is based on the open / closed state of the power switch 103 determines if there is a time to save the abnormality or error information (opened) and if it is determined that the power switch 103 is closed (ie, turned on) (ie, NO), the control flow immediately shifts to an operation end step 710 in which the processing routine of 6 and 7 will leave.

After performing the step 710 For example, the control process receives an operational wait state during the microprocessor 110B performs other control operations and after a predetermined time (eg, 10 ms in the average period) elapses, the operation start step 600 in 6 activated again.

On the other hand, if in step 709 it is determined that the energy switch 103 is open (ie, off) (ie, YES), a self-hold power supply is performed by the power supply relay 102 so that abnormality or error information about a non-volatile data store 113 are transmitted and stored in it by an abnormality history storage section (step 711 ). At this point, they close to the datastore 113 sent various learning information, abnormality occurrence history information, etc. in the engine control unit 100B ,

If the backup processing according to step 711 is completed, the microprocessor 110B subsequently terminate its own operation (step 712 ). As a result, the self-holding operation of the power supply relay becomes 102 by the power supply control circuit 121 released and the excitation of the power supply relay 102 is canceled to interrupt or disconnect the power supply (step 713 ).

As described above, the vehicle remaining fuel amount detecting means 10B according to the second embodiment of the present invention with the variable resistor 105a operatively associated with the position of a float floating on the fuel-liquid level, and the resistance-value measuring section having the resistance value Rv of the variable resistor 105a measures, wherein the residual fuel amount of the resistance value Rv of the variable resistor 105a is appreciated. The resistance value measuring section consists of the measuring current supply circuit (emitter resistance 141 ) and the pulse current supply circuit (emitter resistor 141b ) for supplying electrical energy to the variable resistor 105a , the A / D converter 114 and the microprocessor 110B ,

The microprocessor 110B uses the program memory 111B and the RAM memory 112 in combination and control programs, at least as a read-signal generating section (step 604 ) and resistance value calculating section (step 700 ) are in the program memory 111B saved. The program memory 111B includes the control program constituting the abnormality detection section (step 707 ), and a control program constituting the abnormality history storage section (step 711 ). When the result of determining that at least the voltage Vr across the opposite ends of the variable resistor 105a or the resistance value Rv of the variable resistor 105 calculated by the resistance value calculating section (step 700 ), is excessively large or excessively small while remaining deviated from the predetermined normal range, the abnormality detecting portion (step 707 ) to make an ultimate decision that a contact resistance of the variable resistor 105a is present, an open circuit error of the signal wiring, the variable resistance 105a with the A / D converter 114 connects, a power supply failure in which the signal wiring and the power supply line are short-circuited to each other, or a ground fault in which the signal wiring is short-circuited to the ground, and generates an abnormality message by means of the abnormality notification command section (step 708 ).

The abnormality history storage section (step 711 ) conveys the fact that the abnormality determination section has made a determination of abnormality (step 707 ) to the non-volatile data store 113 and save it in it.

In addition, the program memory closes 111B a control program constituting the average calculation section (step 704 ) and the average calculation section (step 704 ) calculated for the resistance value Rv of the resistance value calculating section (step 700 ) calculated variable resistance 105a the statistical value of either a moving average of the last calculated values at a predetermined number of points or an arithmetic average of a maximum value and a minimum value {ie, (a maximum value + a minimum value) / 2}, or an average value of the amplitude of the pulses.

The measuring current supply circuit (emitter resistance 141 ) in the constant current control circuit 140 forms the power supply circuit for calculating the resistance value Rv of the variable resistor 105a and carries a constant measuring current Is from the on-board battery 101 to the variable resistor 105a through you constant current control circuit 140 , The resistance value calculating section (step 700 ) calculates the resistance value Rv (= Vr / Is) of the variable resistor 105a based on the ratio of the voltage Vr across the opposite ends of the variable resistor 105a and the measuring current Is in the form of the supplied constant current.

Accordingly, the A / D converter 114 the resistance Rv only by measuring the voltage Vr across the opposite ends of the variable resistor 105a to calculate. In addition, the measured current Is is smaller than the pulse current Ip, so that the power consumption of the constant current control circuit 140 can be reduced or suppressed and therefore a low-cost circuit of small size can be used as a constant current control circuit 140 ,

In addition, the pulse current supply circuit cooperates (emitter resistor 141b ) in the constant current control circuit 140 with the constant switching circuit (transistor 147 ) for the measuring current supply circuit (emitter resistor 141 ). When a pulse current supply command DR from the microprocessor 110B is provided, the constant switching circuit (transistor 147 ) of the constant current control circuit 140 supplied current from the measuring current Is to the pulse current Ip. Accordingly, the constant pulse current can be supplied regardless of a variation in the power supply voltage Vb or a change in the resistance value Rv of the variable resistor 105a , Also, the constant current control circuit 140 for measuring the power supply can be used as the pulse current supply circuit, so that the measuring current supply circuit and the pulse current supply circuit can be achieved with an inexpensive circuit configuration.

In addition, precaution was taken for the serial communication line with the microprocessor 110B connected, wherein the second microprocessor 81 with the microprocessor 110B and the display console 108B passing through the second microprocessor 81 is controlled, connected via the serial communication line. The microprocessor 110B consists of an engine control microprocessor with at least one fuel injection control function in addition to the residual fuel amount estimation function mentioned above, and the program memory 111B that cooperates with this microprocessor includes the waste quantity conversion section and a control program in the form of at least one of the progress notification determination section and the boundary detection section.

The remaining fuel amount conversion section (step 720 ) calculates the current remaining fuel amount based on the average resistance value R0 calculated by the average calculating section (step 704 ) and the conversion equation or the data table of the resistance value with respect to the rest fuel quantity characteristic, in advance in the program memory 111B are stored.

The progress notification determination section (step 721 ) and the boundary determination section (step 722 ), respectively, the average resistance value R0 calculated by the average calculating section is compared (step 704 ) with the average message resistance value or the resistance limit in advance in the program memory 111B and generates at least one of a remaining fuel amount reduction progress message display command for the fuel cut progress notification display 84 and a limit alarm indication command for the limit alarm indication 85 ,

In addition, the microprocessor sends 110B the value of the residual fuel amount calculated by the remaining fuel amount conversion section (step 720 ), a display command in accordance with the progress message determination section (step 721 ) or the boundary determination section (step 722 ), and an abnormality notification command generated at least by the abnormality determination section (step 707 ) to the second microprocessor 81 through the serial signal communication line.

The display console 108B closes at least the remaining fuel quantity display 83 at least one of the remaining fuel amount reduction progress message indication 84 and the limit alarm indicator 85 , the abnormality detector 86 for reporting an abnormality or error alarm caused by microprocessor 110B is produced.

Accordingly, the residual fuel amount by the engine control unit 100B calculated and the result of this calculation is via serial transmission to the display console 108B Posted. As a result, the control load of the second microprocessor 81 in the display console 108B be further mitigated.

Note here that the serial communication line connecting the engine control unit 100B and the display console 108B is connected, originally or basically provided for sending a plurality of types of abnormality notification commands to the engine control unit 100B so no additional hardware is required.

In addition, the engine control unit 100B In order to determine the validity of a variation property between the accumulated amount of injected fuel and the amount of residual fuel, gas leakage from a fuel tank, etc., the engine control unit 100B use the residual fuel amount information to seek a comparison between the tank internal volume and the tank internal pressure.

Although in the above description, the A / D converter 114 of 16 channels of A / D conversion for each input channel in accordance with a command from the microprocessor 110A or 110B performs the control mode of the A / D converter 114 be changed in the following way. That is, the A / D conversion for 16 channels is sequentially performed in accordance with an A / D conversion command from the microprocessor 110A or 110B and the results of the conversions are stored in a buffer located in the A / D converter 114 is installed. After completion of the A / D conversion, an A / D conversion completion signal is fed back, causing the microprocessor 110A or 110B can read out the digital conversion value of a prescribed channel by designating an address in the buffer memory.

In the case of such a mailing conversion method, no specific waiting time as shown in step 203 of the 2 or in the step 603 of the 6 and reading the digital conversion value of the voltage Vr across the opposite ends of the variable resistor 105a will not run at a time when the microprocessor 110A or 110B generates a pulse energy supply command, but waiting for a cycle may instead be performed. In addition, the A / D conversion can be performed even during the pulse power supply, but the channel allocation signal 116a is regarded as a read-time signal and the A / D conversion value can not be read out during the pulse power supply or immediately thereafter.

In the above description, the microprocessors work 110A . 110B as engine control unit. In general, a motor control unit is provided with a serial communication line through which various types of input sensors and electric loads are monitored for their abnormality state to perform motor control, and an abnormality notification command is sent upon the occurrence of some abnormality toward a display console. Therefore, information about the residual fuel amount and those items concerned can be sent using this communication line. When such information related to the remaining fuel amount and the like is sent to the display panel via the engine control unit, the engine control unit can obtain new information. As a result, the presence or absence of the total abnormality can be made, for example, by making a comparison between the accumulated one Value of the injected fuel amount and the amount of change of the residual fuel amount can be determined.

moreover it is when information related to the pressure sensor or measuring the internal pressure of a gas or fuel tank and ambient temperature information entered into the engine control unit, possible, the engine control unit as a device for determining the presence or absence of fuel sweating with high accuracy based on a Relationship between a volume of space to be used by Subtracting the amount of remaining fuel from the volume of the fuel tank, the ambient temperature and the Tank pressure. As a result, information regarding the fuel be handled centrally.

however needs the microprocessor used in the present invention not necessarily a microprocessor used in the engine control unit is installed, but instead can display in a residual fuel amount be provided to the signal processing and the remaining fuel quantity display to perform a fuel level sensor in an integrated manner.

moreover The remaining fuel quantity indicator can be provided with a digital display be used to alert or warn of the reduced residual fuel can serve as e.g. by flashing, if the residual fuel quantity is reduced below a prescribed level, and the period of flashing, when the residual fuel quantity reaches a limit.

moreover the residual fuel amount is generally determined using a specified or displayed according to the percentage of the Represents residual fuel amount to the volume of the fuel tank or represents but it can also be used the value of the volume in liters or the estimated remaining distance, which one is able to drive, can for this purpose be used.

In addition, in the measuring current supply circuit, the fixed resistor 129 of the 1 includes or the measuring current supply circuit, the emitter resistance 141 of the 5 includes, the resistance value Rv of the variable resistor 105a arithmetically, even if the value of the measured current is not actually measured, but a detection circuit may be provided for detecting one of the variable resistance 105a current to be supplied, and the current thus detected may be input to the microprocessor 110A or 110B via the A / D converter 114 be entered.

Also, the A / D converter 114 in the microprocessor 110A or 110B be installed or the program memory 111A or 111B and / or the data store 113 can be provided separately and with the microprocessor 110A or 110B be connected via a bus or a serial connection.

While the Invention has been described in terms of preferred embodiments, Professionals will recognize that the invention with modifications within the scope of the appended claims in the Practice can be implemented.

Claims (10)

Vehicle remaining fuel amount detecting means (FIG. 10A . 10B ), which has a variable resistance ( 105a ) operatively connected to the position of a float floating on the fuel liquid surface ( 105b ), and a resistance value measuring section which determines the resistance value of the variable resistor ( 105a ), the remaining fuel amount being determined from the resistance value of the variable resistor (34) measured by the resistance value measuring section 105a ) is estimated and displayed, characterized in that the resistance value measuring section is selected from a measuring current supply circuit ( 129 . 141 ) and a pulse current supply circuit ( 123 . 141b ) for supplying electrical energy to the variable resistor ( 105a ), an A / D converter ( 114 ) and a microprocessor ( 110A . 110B ); the microprocessor ( 110A . 110B ) a program memory ( 111A . 111B ) and a RAM memory ( 112 ) are used in combination and control programs that are at least as a read signal generating section ( 204b . 604 ) and a resistance value calculating section ( 300 . 700 ), in the program memory ( 111A . 111B ) are stored; the festival resistance ( 129 . 141 ), a measuring current (Is) from an on-board battery ( 101 ) to the variable resistor ( 105a ) to calculate the resistance value therefrom; the pulse current supply circuit ( 123 . 141b ) periodically a pulse-shaped current (Ip) which is greater than the measuring current (Is) the variable resistance ( 105a ) from the on-board battery ( 101 ) with a power supply period (Tp) to increase the contact resistance of the variable resistor (Tp). 105a ) to suppress; the A / D converter ( 114 ) the value of one between opposite ends of the variable resistor ( 105a ) applied voltage (Vr) converts digitally and the thus obtained digital conversion data to the RAM memory ( 112 ) by the microprocessor ( 110A . 110B ) based on a read time signal ( 115a ) transmitted by the reader generation section ( 204b . 604 ) is produced; the read signal generation section ( 204b . 604 ) the read-time signal ( 115a ) of the reading period (Ts) of the A / D converter ( 114 ) with a timing except for a period in which the pulse current supply circuit ( 123 . 141b ) supplies the pulsed current (Ip); the resistance value calculating section ( 300 . 700 ) the resistance value (Rv (= Vr / Is)) of the variable resistor ( 105a ) based on the ratio of the voltage (Vr) across the opposite ends of the variable resistor ( 105a ) is calculated to the measuring current (Is); and the residual fuel amount of the resistance value (Rv) of the variable resistor ( 105a ) is estimated. Vehicle remaining fuel amount detecting means (FIG. 10A . 10B ) according to claim 1, characterized in that the average value of the energization period (Tp) representing the generation period of the pulse by the pulse current supply circuit ( 23 . 141b ) is set to a time interval which is greater than an average value of the read period (Ts) which determines the generation period of the read-time signal (Ip). 115a ) generated by the read signal generating section ( 204b . 604 ) is produced. Vehicle remaining fuel amount detecting means (FIG. 10A . 10B ) according to claim 1 or 2, characterized in that the resistance value measuring section is provided with an input filter circuit ( 130 ) and a stability waiting section ( 203 . 603 ); the input filter circuit ( 130 ) comprises a low-pass filter for suppressing one between the variable resistor ( 105a ) and an analog input terminal of the A / D converter ( 114 ) connected noise voltage; the stability waiting section ( 203 . 603 ) waits for a period of time during which the output voltage of the input filter circuit ( 130 ) in a predetermined period after the pulse current supply circuit ( 123 . 141b ) has supplied the pulsed current (Ip) attenuated; and the read signal generation section ( 204b . 604 ) the read-time signal ( 115a ) of the reading period (Ts) of the A / D converter ( 114 ) with a timing except for a period in which the pulse current supply circuit ( 123 . 141b ) supplies the pulsed current (Ip) and, with the exception of the waiting period of the stability waiting section ( 203 . 603 ). Vehicle remaining fuel amount detecting means (FIG. 10A . 10B ) according to claim 3, characterized in that the program memory ( 111A . 111B ) includes a control program having an abnormality detecting section ( 307 . 707 ), and a control program including an abnormality history storage section (FIG. 311 . 711 ) forms; the abnormality detection section ( 307 . 707 ) with an abnormality notification command section ( 308 . 708 ) cooperates and if the result of a determination that at least one of the voltage (Vr) across the opposite ends of the variable resistor ( 105a ) and that by the resistance value calculating section ( 300 . 700 ) calculated resistance value (Rv) of the variable resistor ( 105a ) is excessively large or excessively small, while a deviation from a predetermined normal region continues, the abnormality detecting portion (FIG. 307 . 707 ) functions to make a determination that a contact resistance of the variable resistor ( 105a ), an open circuit fault of the signal wiring between the variable resistor ( 105a ) and the A / D converter ( 114 ), a power supply fault in which the signal wiring and a power supply line are short-circuited with each other or a ground fault in which the signal wiring is short-circuited to ground has occurred, and an abnormality message by means of the abnormality notification command section (FIG. 308 . 708 ) generated; and a non-volatile data store ( 113 ) as an abnormality history storage section ( 311 . 711 ), and one by the abnormality detecting section ( 307 . 707 ) carried out Abnormalitätsbestimmung to the data store ( 113 ) is transmitted and stored therein. Vehicle remaining fuel amount detecting means (FIG. 10A . 10B ) according to claim 4, characterized in that the program memory ( 111A . 111B ) includes a control program having an average calculation section ( 304 . 704 ) forms; and the average calculation section ( 304 . 704 ) the resistance value (Rv) of the resistance value calculating section ( 300 . 700 ) calculated variable resistance ( 105a ) calculates an average resistance value (R0) which is a statistical value of either a moving average of the last calculated values at a predetermined number of points, or an arithmetic average of a maximum value and a minimum value {ie, (a maximum value + a minimum value) / 2 }, or a central value of the pulse amplitude. Vehicle residual current detection device ( 10A ) according to claim 1, characterized in that the measuring current supply circuit ( 129 ) a fixed resistor ( 129 ) of a known resistance value connected in series with the variable resistor ( 105a ) and connecting a series connection, the fixed resistor ( 129 ), with the onboard battery ( 101 ) the measuring current (Is (= Vb - Vr) / Rs)) based on a relationship between the power supply circuit (Vb) of the on-board battery ( 101 ), the voltage (Vr) across the opposite ends of the variable resistor ( 105a ), and the resistance (Rs) of the fixed resistor ( 129 ); the individual value of the power supply voltage (Vb) and the voltage (Vr (= Rv × Is)) across the respective ends of the variable resistor (Vb) 105a ), in the RAM memory ( 112 ) via the A / D converter ( 114 ) and the microprocessor ( 110A ) get saved; and the resistance value calculating section (FIG. 300 ) the resistance value (Rv (= Vr (Is) = Rs × Vr / (Vb-Vr)) of the variable resistor ( 105a ) based on the ratio of the voltage (Vr) across the opposite ends of the variable resistor ( 105a ) is calculated to the measuring current (Is). Vehicle remaining fuel amount detecting means (FIG. 10B ) according to claim 1, characterized in that the measuring current supply circuit ( 141 ) in a constant current control circuit ( 140 ) and a constant measuring current (Is) from the on-board battery ( 101 ) to the variable resistor ( 105a ) to calculate the resistance value thereof; and the resistance value calculating section (FIG. 700 ) the resistance value (Rv (= Vr / Is)) of the variable resistor ( 105a ) based on the ratio of the voltage (Vr) across opposite ends of the variable resistor ( 105a ) is calculated to the constant measuring current (Is). Vehicle residual current detection device according to claim 7, characterized in that the pulse current supply circuit ( 141b ) is made selectively conductive by means of a constant switching circuit ( 147 ) for the constant current control circuit ( 140 ) and the constant switching circuit ( 147 ) comprises a transistor circuit and upon receiving a command (DR) for supplying the pulsed current (Ip) to the constant current control circuit ( 140 ) is switched from the measuring current (Is) to the pulsed current (Ip). Vehicle remaining fuel amount detecting means (FIG. 10A ) according to claim 5, characterized by further comprising a serial communication line connected to the microprocessor ( 110A ), a second microprocessor ( 81 ) connected to the microprocessor ( 110A ) is connected via the serial communication line, and a display console ( 108A ) through the second microprocessor ( 81 ) is controlled; the microprocessor ( 110A A motor control microprocessor is provided with at least one fuel injection control function in addition to a function of estimating the residual fuel amount, and an average resistance value (R0) of the average calculation portion (R0). 304 ) calculated variable resistance ( 105a ) and one through the abnormality determination section ( 307 ) generated abnormality message command to the second microprocessor ( 81 ) via the serial signal communication line; the display console ( 108A ) a remaining fuel quantity indicator ( 83 ) indicative of the remaining fuel amount, at least one of a reduction progress message indication ( 84 ) and a limit alarm display ( 85 ) for the residual fuel quantity, and an abnormality detector ( 86 ), one through the microprocessor ( 110A ) reports an abnormality alarm; the second microprocessor ( 81 ) with a second program memory ( 82A ) in which a control program stored as a residual vehicle fuel amount conversion section (FIG. 420 ) and at least one progress message determination section ( 421 ) and a boundary detection section ( 422 ); the vehicle residual fuel amount conversion section (FIG. 420 by converting the current remaining fuel amount based on the average resistance value (R0) received from the serial communication line and a conversion equation or a data table of a resistance value to the remaining fuel quantity characteristic map in advance in the second program memory ( 82A ) are calculated; the progress message determination section ( 421 ) generates a remaining fuel amount reduction progress message display command by making a comparison between the average resistance value (R0) and a progress message resistance value stored in advance in the second program memory (R0); 82A ) is stored; and the boundary determination section generates a boundary alarm indication command by making a comparison between the average resistance value (R0) and a boundary resistance value stored in advance in the second program memory (R0). 82A ) has been stored. Vehicle residual flow amount detection device ( 10B ) according to claim 5, characterized by further comprising a serial communication line connected to said microprocessor ( 110B ), a second microprocessor ( 81 ), with the microprocessor ( 110B ) is connected via the serial communication line, and a display console ( 108B ) through the second microprocessor ( 81 ) is controlled; the microprocessor ( 110B ) from an engine control microprocessor having at least one fuel injection control function in addition to a function of estimating the residual fuel amount, and the program memory ( 111B ), with the microprocessor ( 110B ) cooperates, further, a vehicle residual fuel amount conversion section ( 720 ) and a control program functioning as at least one of a progress message determination section (14) 721 ) and a boundary determination section ( 722 ); the remaining fuel amount conversion section (FIG. 720 ) the current residual fuel amount based on the average calculation section (16) 704 ) calculated average resistance value (R0) of the variable resistance ( 105a ) and a conversion equation or a data table of a resistance value against the remaining fuel quantity characteristic curve, which are stored in advance in the program memory ( 111B ) are stored; the progress message determination section ( 721 ) generates a remaining fuel amount reduction progress notice indication command by making a comparison between the average resistance value (R0) and a previous one in the program memory ( 111B stored progress message resistance value; the boundary determination section generates a boundary alarm indication command by making a comparison between the average resistance value (R0) and a boundary resistance value stored in advance in the second program memory (R0); 82A ) has been stored; the microprocessor ( 110 ) the value of the residual fuel amount conversion section ( 720 ), a display command in accordance with the progress message determination section (FIG. 721 ) or the border determination section ( 722 ) and an abnormality notification command in accordance with the abnormality determination section (FIG. 707 ) to the second microprocessor ( 81 ) via the serial signal communication line; and the display console ( 108B ) a remaining fuel quantity indicator ( 83 ) indicative of a remaining fuel amount, at least one of a reduction progress message indication ( 84 ) and a limit alarm display ( 85 ) includes for the residual fuel quantity and an abnormality detector ( 86 ), which is controlled by the microprocessor ( 110B ) generate abnormality alert.