RU2339009C2 - Method for compensation of fuel tank level pickup reading error and onboard computer to this effect - Google Patents

Abstract

FIELD: transport.

SUBSTANCE: onboard computer (OC) is set to fuel level pickup calibration mode (FLC), the data on amount of available tank fuel is written into ROM, and the changes in the FLC calibration table are introduced. Now, the OC is switched from the calibration mode, the FLC characteristic is generated and output into a graphic display as a plot. The OC incorporates ADC, micro computer with ROM, display with its driver and, at least, one control component representing an encoder functioning as a selector and push-button switches, the ROM storing the FLC reading error compensation program.

EFFECT: higher accuracy of measuring tank fuel level.

3 cl, 2 dwg

Description

The invention relates to the field of automotive industry and can be used in an automobile information system, including an analog fuel level sensor (hereinafter - FLS) installed in the fuel tank of a car, and a trip computer (hereinafter - MK), which includes an analog-to-digital converter (hereinafter referred to as the ADC), a microcomputer with read-only memory (hereinafter - ROM), at least one control element made in the form of an encoder, and a graphic display with a graphic display driver.

From the prior art (see, for example, patents: US 5847335, MKI ⁶ H01H 9/00, publ. 08.12.1998; US 6856261 B2, MKI ⁷ H03M 1/22, H01H 19/00, publ. 15.02.2005 d) the design of the encoder is known - a control body that implements the functions of the rotary and push switches.

Known (see, for example, patent RU 2269749 C1, IPC G01F 23/36, publ. 10.02.2006, bull. No. 4) and is widely used in the automotive industry design potentiometric FLS, including a lever, a float connected to the first the end of the lever, and a potentiometer whose slider is mechanically connected to the second end of the lever. The error in measuring the fuel level with such a sensor is very high and can reach several liters (see: Za Rulem magazine, No. 3/ 1997, p. 43).

A known method of compensating for the systematic error of the FLS readings of the design described above (see V.V. Litvinenko, A. P. Mayrustru. Automotive sensors, relays and switches. Quick reference. M: LLC “Publishing house“ Za rulyom ””, 2006 ., p. 22-23), which consists in changing the shape of the movable lever of the sensor.

From patent RU 19156 U1, IPC ⁷ G01F 23/14, publ. 08/10/2001, the car’s information system is known, which includes an analog fuel level sensor installed in the car’s fuel tank, and MK, which includes a microcomputer with ROM, a control element, and an information display device. The ROM of the microcomputer stores the calibration table of the FLS in the form of a set of pairs of values "sensor signal" / "amount of fuel".

To obtain the calibration table of the fuel level sensors, fill in the standard fuel portions into the vehicle’s fuel tank, digitize the fuel level sensor signals in the ADC and form a set of pairs of “sensor signal” / “fuel quantity”.

From the description of patent RU 2163005 C2, IPC ⁷ G01F 9/00, 23/30, publ. patent 10.02.2001, the information system of the car is known, which includes a potentiometric fuel level sensor installed in the fuel tank of the car, and MK, which includes an ADC, a microcomputer with ROM, a display with a display driver and a control.

Also known (see: Sosnin D.A., Yakovlev V.F. The latest automotive electronic systems. M .: SOLON-Press, 2005, p. 100) the way the car information system includes an analogue DUT, ADC , a microcomputer with a ROM, a display with a display driver, and a control element, in which the calibration table of the FLS is written in the microcomputer ROM as a set of pairs of “sensor signal” / “fuel amount” values, the voltage level of the sensor signal is measured, it is subjected to analog-to-digital conversion, and compare the obtained value with the value and "sensor signal" from the calibration table. If the obtained value coincides with one of the “sensor signal” values of the calibration table, the “fuel quantity” value corresponding to the “sensor signal” value is determined and displayed on the display.

The prototype of the proposed method is a method of compensating for the error of the FLS test, known from patent RU 2163005 C2, IPC ⁷ G01F 9/00, 23/30, publ. patent 10.02.2001, and implemented in the vehicle’s information system, which includes an analogue DUT and MK, which includes an ADC, a microcomputer with ROM and a display with a display driver.

The prototype method is as follows.

In the ROM ROM MK record the calibration table of the FLS in the form of a set of pairs of values "sensor signal" / "amount of fuel", as well as the maximum permissible deviation of the value "sensor signal". Measure the magnitude of the current signal of the FLS and digitize the measured value in the ADC. The obtained digital value of the sensor signal is compared with the maximum permissible value and if the current value does not exceed the maximum permissible value, the corresponding fuel value is determined using the calibration table and shown on the display screen. Otherwise, it is believed that the measurement was made with an unacceptably large error and reject the result of the current measurement.

For the prototype of the inventive trip computer, the design of the trip computer for the car, known from patent RU 2163005 C2, and which includes an ADC, a microcomputer with ROM and a display with a display driver, is taken.

The objectives of the invention is to improve the accuracy and convenience of measuring the amount of fuel in the fuel tank of a car.

These tasks are solved in the method of compensating for the error of the analogue FLS readings, in which the sensor calibration table is written in the microcomputer ROM as a set of sensor signal / fuel quantity pairs, and for the current measured values that do not coincide with the sensor signal values of the calibration table , the corresponding value of the "amount of fuel" is obtained by calculating by the method of linear interpolation of the "amount of fuel".

The problems are solved in the way that the calibration table is refined during the operation of the vehicle by transferring the MK to the calibration mode of the fuel level sensor and writing to the ROM new pairs of values "sensor signal" / "fuel quantity".

The “fuel quantity” value for a new pair of the calibration table can be obtained using various techniques. In particular, a known amount of fuel can be poured into the fuel tank of a vehicle or removed from it. Removing a known amount of fuel can be done by draining or burning in the cylinders of the car engine with the calculation of the time of the open state of the nozzle.

For the most accurate measurement, perform the following steps.

A known amount of fuel is poured into the vehicle’s fuel tank, the MK is put into the DUT calibration mode, the new known current value of the fuel amount is written to the ROM, the current fuel value is confirmed with the control, the value of the current DUT signal is measured, digitized, a new pair of values sensor signal ”/“ fuel quantity ”of the calibration table, write it to the microcomputer ROM and remove the MC from the calibration mode of the fuel level sensor, and after making changes to the calibration table, the character is recalculated on the abscissa and ordinates of which values “sensor signal” and “amount of fuel” are plotted on the abscissa and ordinates of which are displayed on the display axes and on the display axes and displayed on the display screen FLS calibration schedule.

These tasks are also solved in a trip computer, which includes an ADC, a microcomputer with ROM and a display with a display driver.

The tasks are solved in that the MK is equipped with a control body made in the form of an encoder that implements the functions of the rotary and push switches, the display is graphic, and the program for compensating the error of the FLS readings that implements the inventive method is recorded in the ROM.

The invention is illustrated by the following drawings.

Figure 1 shows a block diagram of a vehicle information system in which the implementation of the proposed method is possible.

Figure 2 shows the characteristic of the FLS 1, built on two points, and the refined characteristic of the FLS 1 obtained in accordance with the claimed method.

The inventive method can be implemented in a car information system, which includes (see Figure 1) an analog fuel level sensor 1 and a car trip computer 2, the latter includes an ADC 3, a microcomputer 4 with ROM 5, and a display 6 with a display driver 7 .

To implement the method, taking into account the best solution to the tasks, the following changes in the design of the MK are performed.

MK provide control body 8, which is performed in the form of an encoder that implements the functions of rotary and push switches.

Using the encoder, when compensating for the error of the FLS readings, the most convenient are the operation of selecting values or operating modes (by turning the encoder shaft) and the operation of confirming the selection (by axial movement of the encoder shaft).

Display 6 perform graphic. Thanks to this, it becomes possible to display changing graphic information on it and the process of compensating for the error of the FLS readings becomes visual. At the same time, the driver 7 is replaced to control the graphic display 6.

In ROM 5 MK 2 write the program for compensating the error of the readings of the FLS, which implements the inventive method.

The presence in the ROM of the program for compensating for the error of the readings of the FLS allows you to apply the claimed method to any user, for example, the car owner.

The method in the best case implementation is carried out by performing the following sequence of actions.

Write in ROM 5 microcomputers 4 MK 2 calibration table FLS 1 as a combination of several pairs of values "sensor signal" / "amount of fuel". In the simplest case, two pairs of values “sensor signal” / “fuel quantity” are entered in ROM 5.

Place the car on a flat horizontal platform.

Start and warm up the car engine to ensure a stable supply voltage to the ADC 3 MK 2.

Fill the car tank with a known amount of fuel.

MK 2 is put into the calibration mode of the FLS by changing the position of the encoder shaft 8.

Enter using the encoder 8 the value of the known amount of fuel.

Measure the signal of the FLS 1.

Convert the ADF 3 signal into ADC 3 into digital form and get a new value “sensor signal”.

Form a new pair of values "sensor signal" / "fuel quantity" of the calibration table and write it to ROM 5 microcomputers 4 MK 2.

MK 2 is transferred from the DUT calibration mode to the operating mode by changing the position of the encoder shaft 8.

At the user’s command, submitted with the help of encoder 8, an updated characteristic of the FLS 1 is formed for display on the graphic display 6 in the form of a graph, on the abscissa and ordinates of which the values “sensor signal” and “fuel quantity” are plotted. At the same time, the characteristics of the FLS 1 are recalculated in the areas adjacent to the new pair of values.

The calibration diagram of the FLS 1 is shown on the display screen.

Figure 2 shows the initial characteristic of the FLS, built on two pairs of values of the calibration table, and the characteristic obtained in accordance with the claimed method.

The characteristic of the FLS 1 can be presented, for example, in the form of a graph in the coordinate system, the abscissa of which shows the voltage values in volts, U, V, corresponding to the “sensor signal” values, and the ordinate axis shows the values of the fuel quantity F, l, in tank car.

Initially, in the ROM 5 of the microcomputer 4 of the trip computer 2, the calibration table of the FLS 1 is recorded in the form of two pairs of values "sensor signal" / "amount of fuel". One of these points is located on the abscissa axis, which corresponds to an empty tank, and the second is on the ordinate axis, which corresponds to the full tank of the car. The graph of such a characteristic is represented by line 1.

As you enter into the ROM in accordance with the proposed method, new pairs of values of the calibration table, the characteristic of the FLS takes the form of a broken line 2.

The proposed technical solution makes it possible to construct the characteristics of the FLS with any required accuracy, which is determined by the number of new pairs of values of the calibration table entered during the operation of the vehicle in the ROM ROM;

Thanks to the presence of a graphic display, the user can most easily determine the sections of the characteristics of the FLS that need to be clarified.

Claims (3)

1. A method of compensating for an error in the readings of the fuel level sensor in the car’s information system, which includes an analog fuel level sensor installed in the car’s fuel tank, and a trip computer, which includes an analog-to-digital converter, a microcomputer with a permanent recording device, and a graphic display with a display driver and at least one control element, in which the sensor calibration table is written to the read-only memory of the trip computer microcomputer fuel ram as a set of pairs of “sensor signal” / “fuel quantity” values, characterized in that the calibration table of the fuel level sensor is updated during the operation of the vehicle by putting the trip computer in the calibration mode of the fuel level sensor and writing a new pair to the memory of the trip computer values "sensor signal" / "fuel quantity". 2. The method according to claim 1, characterized in that, to clarify the calibration table, a known amount of fuel is poured into the vehicle’s fuel tank, after which the trip computer is switched to the calibration mode of the fuel level sensor, and a new known current value of the quantity is written into the memory of the trip computer microcomputer fuel, confirm the input of the current fuel value using the control, measure the current signal of the fuel level sensor, digitize it, form a new pair of values sensor ignition "/" fuel quantity "of the calibration table, write it to the permanent memory of the microcomputer and put the trip computer out of the calibration mode of the fuel level sensor, and after making changes to the calibration table, recalculate the characteristics of the fuel level sensor, form on the user's command to output to the display screen the updated characteristic of the FLS in the form of a graph, on the abscissa and ordinates of which the values "sensor signal" and "fuel quantity" are plotted, and are displayed on the display screen m trip computer calibration graph fuel level sensor. 3. Trip computer, which includes an analog-to-digital converter, a microcomputer with read-only memory, a display driver, a display and a control, characterized in that the control is made in the form of an encoder that implements the functions of the rotary and push switches, the display is graphical, and the ROM contains a program to compensate for the error of the fuel level sensor.

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