DESC:
FIELD
The present disclosure generally relates to automobile engineering.
More particularly, the disclosure relates to fuel monitoring systems and methods for automobiles.
BACKGROUND
Automobile parts used for sensing and indicating fuel level in a fuel tank are known for quite some time. Examples of such parts are generally found in the fuel gauges of motor vehicles, aircraft, and boats. Traditional fuel gauges that move between full and empty positions are helpful for drivers who wish to calculate mileage and to know when there is need of refueling the fuel tank.
Generally, the automobile parts for fuel monitoring include a sensing unit and an indicator unit. The sensing unit is located in the fuel tank of the automobile. It consists of a float, usually made of foam, connected to a thin, metal rod. The end of the rod is mounted onto a variable resistor (potentiometer). As the tank empties, the float drops and slides the rod along the resistor, increasing its resistance, whereas the indicator unit simultaneously measures and displays the amount of electrical current flowing through the sensing unit. When the tank level is high and the maximum current is flowing, the needle points to "F" indicating a full tank because of low resistance. When the tank is empty and a negligible amount of current is flowing, the needle points to "E" indicating an empty tank because of high resistance. However, the non-conventional design of the fuel tank used in the automobiles leads to imprecise reading of the fuel level in the fuel tank and displaying of erroneous readings on a display.
Another major drawback of the aforementioned sensing unit is that the sensor readings are affected by the changes in the atmospheric conditions inside the fuel tank, which are mostly governed by pressure, humidity and temperature. This inherently induces errors in the fuel measurement readings and creates inconvenience and confusion for the driver.
Therefore, there is a long felt need for a system that aims at providing accurate fuel level readings in automobiles. Further, there is a need for a fuel level measuring system that automatically calibrates based on the environment inside the fuel tank.
OBJECTS
Some of the objects of the present invention are aimed to ameliorate one or more problems of the prior art or to at least provide a useful alternative are described herein below:
An object of the present invention is to provide an auto-calibrated sensor based system and method for fuel level monitoring in an automobile.
Another object of the present invention is to provide a system that utilizes a pressure sensor for measuring a fuel level in a fuel tank.
Another object of the present invention is to provide a system that automatically calibrates a sensor used for measuring fuel level in a fuel tank.
Another object of the present invention is to provide a system that is capable of eliminating factors governed by atmospheric conditions which introduce errors in a speedometer reading of the automobile.
Another object of the present invention is to provide a system that can be easily interfaced with an existing fuel tank of an automobile.
Other objects and advantages of the present invention will be more apparent from the following description when read in conjunction with the accompanying figure, which are not intended to limit the scope of the present disclosure.
SUMMARY
Described herein is a method for fuel monitoring in a fuel tank of an automobile, the method comprising checking, using a control unit, whether time (t) greater than or equal to a predetermined time period lapsed after the ignition of an engine of the automobile, if yes, initiating sampling of an output voltage using a sensor based system having one or more pressure sensors disposed inside the fuel tank, checking an output voltage (V) of at least one pressure sensor of the sensor based system, wherein the control unit checks whether the sensor output voltage (V) is less than a predetermined value, and initializing an odometer reading counter (c), if the sensor output voltage (V) is less than a predetermined value, loading the reading of the output voltage (V) into a first variable (X1) and initiating monitoring of the odometer for retrieving an odometer reading, checking whether the odometer reading counter (c) is increased by a predetermined value in distance, if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the sensor output voltage (V) value retrieved in real time is loaded into a second variable (X2), continuing averaging and retrieving at least two consecutive averages corresponding to the first variable (avg-X1) and the second variable (avg-X2), checking whether a difference of the averages of the first and second variables (avg-X1 – avg-X2) is greater than a predetermined value, wherein the value of X2 is retrieved in real time, and moving the value of X2 into X1, if yes, resetting the odometer reading counter (c) to zero and checking whether the odometer reading counter (c) increased by the predetermined value in distance, if no, incrementing the odometer reading counter (c) and continuing averaging the odometer reading and further incrementing the odometer reading counter (c) till three consecutive average values of X1 and X2 are retrieved and compared, checking whether the odometer reading counter (c) is greater than or equal to three, if yes, retrieving and initializing the sensor output voltage as the base voltage in real time; if the sensor output voltage (V) is greater than the predetermined value, loading the reading of the output voltage (V) into a first variable (x1) and initiating monitoring of the odometer for retrieving an odometer reading, checking whether the odometer reading counter (c) is increased by a predetermined value in distance, if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the sensor output voltage (V) value retrieved in real time is loaded into a second variable (x2), continuing averaging and retrieving at least two consecutive averages corresponding to the first variable (avg-x1) and the second variable (avg-x2), checking whether a difference of the averages of the first and second variables (avg-x1 – avg-x2) is greater than a predetermined value, wherein the value of x2 is retrieved in real time, and moving the value of x2 into x1, if yes, resetting the odometer reading counter (c) to zero and checking whether the odometer reading counter (c) increased by the predetermined value in distance, if no, incrementing the odometer reading counter (c), and continuing averaging the odometer reading and further incrementing the odometer reading counter (c) till four consecutive average values of x1 and x2 are retrieved and compared, checking whether the odometer reading counter (c) is greater than or equal to four, and if yes, displaying a fuel symbol and an error message on a LCD screen.
In accordance with an embodiment, the method comprises checking at least one more time, whether the odometer reading is increased by the predetermined value in distance in distance, and if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the value initially loaded into X1 is discarded and the value of X2 is moved into X1, and X2 is loaded with the current sensor output voltage (V) value retrieved in real time.
In accordance with an embodiment, the method comprises checking at least one more time, whether the odometer reading is increased by the predetermined value in distance, and if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the value initially loaded into x1 is discarded and the value of x2 is moved into x1, and x2 is loaded with the current sensor output voltage (V) value retrieved in real time.
In accordance with an embodiment, the predetermined value in distance is 1km.
In accordance with an embodiment, the predetermined value of the pressure sensor output voltage (V) is 1.38Volt.
In accordance with an embodiment, the difference (avg-X1 – avg-X2) of 15 mV is considered as a positive condition for auto-calibration.
In accordance with an embodiment, the predetermined time period is 15 seconds.
In accordance with an embodiment, the fuel symbol blinks at a rate of 1 blink per sec.
BRIEF DESCRIPTION OF DRAWINGS
The auto-calibrated sensor based system and method for fuel monitoring in automobiles will now be described with the help of accompanying drawings, in which:
Sole FIGURE 1 illustrates a flow diagram of a method for implementing an auto-calibrated sensor based system for fuel monitoring in automobiles, in accordance with the present disclosure.
DETAILED DESCRIPTION
The disclosure will now be described with reference to the accompanying embodiments which do not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.
The embodiments herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiments in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.
Generally, a speedometer in an automobile is provided to facilitate a driver who is driving the automobile with the knowledge of the speed at which the automobile is running. Basically, the speedometer or a speed meter is a gauge that measures and displays the instantaneous speed of the automobile. This enables the driver to calculate the mileage of the automobile based on the distance travelled and the fuel consumed. Due to the non-conventional structure of the fuel tanks used in the existing automobiles, the type of fuel gauges that are currently being used, and the involvement of various atmospheric conditions inside the fuel tank leads to improper indications on the speedometer. This creates inconvenience and confusion for the driver while calculating the mileage of the automobile.
To obviate the aforementioned drawbacks, the present disclosure envisages an auto-calibrated sensor based system and method for fuel level monitoring in automobiles. The system of the present disclosure utilizes pressure sensors for measuring a fuel level in a fuel tank of the automobile. Since, the pressure sensor changes its behavior based on the atmospheric conditions such as pressure, humidity, temperature and the like, the system envisages an auto-calibration methodology that is capable of identifying the changes and calibrate an output of the pressure sensor based on the changing conditions.
The auto-calibration methodology is enabled to identify pressure sensor’s absolute pressure output voltage at an instant by taking into account sensor tolerances and atmospheric conditions. The output of the pressure sensor varies linearly with respect to the fuel level. Accordingly, there is provided a control unit that is configured to detect if there is any change in the output of the pressure sensor. The control unit is also configured to automatically calibrate the fuel volume indications/fuel level readings as displayed on the speedometer based on the reading of the pressure sensor. This facilitates in removing erroneous readings displayed on the speedometer.
In accordance with the present disclosure, typically, the pressure sensor used is a Micro-Electro Mechanical systems (MEMs) based pressure sensor. The aforementioned type of the pressure sensor produces an output voltage representing a reading of the fuel level in the fuel tank. The pressure sensor is configured in such manner that when the fuel in the fuel tank reduces, the output voltage produced by the pressure sensor also reduces in a corresponding manner.
In accordance with the present disclosure, the pressure sensor is arranged inside the fuel tank to determine the fuel level. The arrangement of the pressure sensor inside the fuel tank is such that the reserve fuel remains below the pressure sensor. If the automobile starts running on the reserve fuel, the output voltage of the pressure sensor remains constant or unchanged. In other words, if no change is observed in the output voltage of the pressure sensor, this interprets that the fuel present in the automobile is the reserve fuel. This reading in the output voltage of the pressure sensor is referred to as ‘base-voltage’.
The automobile fuel system is designed in a manner such that the automobile can run up to 30-40 km with the reserved fuel. If no change is observed in the pressure sensor output voltage for say 10 km, then the fuel in the fuel tank is the reserve fuel and the output voltage reading of the pressure sensor is taken as absolute or base-voltage. Accordingly, the fuel indication is automatically modified.
In an embodiment, the base-voltage of the pressure sensor is taken as 1.38 Volt, which indicates fuel availability. In another embodiment, the output values of the pressure sensors in terms of voltage are collected at a sampling rate. In one embodiment, the sampling rate is 16 msec. Once, the samplings of the pressure sensor voltage is complete for one km, the auto-calibrated sensor based system is capable of averaging the pressure sensor output voltage sampled for the next one km. The system compares the averaged values with the consecutive samples before confirming the level of fuel left in the fuel tank.
In accordance with an aspect of the present disclosure, the pressure sensors are auto-calibrated. If the difference between the current sampled value of the pressure output voltage with the earlier sampled value of the pressure output voltage is 15 mV, this is considered as a positive condition for auto-calibration. Typically, ten samples are considered for the purpose of running a comparison and confirming auto-calibration.
Referring to FIGURE 1, there is shown a flowchart illustrating the steps for implementing an auto-calibrated sensor based system for fuel monitoring in automobiles in accordance with the present disclosure. The method, in accordance with the present disclosure, includes the following steps:
• at step 102, checking, at a control unit, whether time (t) greater than or equal to 15 seconds lapsed after the ignition of an engine of an automobile;
• at 104, if yes, initiating sampling of pressure output voltage and filtering of emissions of the automobile;
• at 106, checking an output voltage (V) of a pressure sensor disposed inside a fuel tank of the automobile, wherein the control unit checks whether the pressure sensor output voltage (V) is less than 1.38Volt, and initializing an odometer reading counter (c);
o if yes,
? at step 108, loading the reading of the output voltage (V) into a first variable (X1) and initiating monitoring of the odometer for retrieving an odometer reading;
? at step 110, checking whether the odometer reading counter (c) is increased by 1 km in distance;
? if yes, at step 112, averaging the odometer reading for 1 km and retrieving the pressure sensor output voltage (V) value in real time, wherein the pressure sensor output voltage (V) value retrieved in real time is loaded into a second variable (X2);
? at step 114, checking again, whether the odometer reading is increased by 1 km in distance;
? if yes, at step 116, averaging the odometer reading for 1 km and retrieving the pressure sensor output voltage (V) value in real time, wherein the value initially loaded into X1 is discarded and the value of X2 is moved into X1, and X2 is loaded with the current pressure sensor output voltage (V) value retrieved in real time;
? at step 118, continuing averaging and retrieving at least two consecutive averages corresponding to the first variable (avg-X1) and the second variable (avg-X2);
? at step 120, checking whether the difference (avg-X1 – avg-X2) is greater than 15 mV, wherein the value of X2 is retrieved in real time, and moving the value of X2 into X1;
o if yes, then at 122, resetting the odometer reading counter (c) to zero and go to step 110;
o if no, the at 124, incrementing the odometer reading counter (c) and continuing averaging the odometer reading and further incrementing the odometer reading counter (c) till three consecutive average values of X1 and X2 are retrieved and compared;
? at 126, checking whether the odometer reading counter (c) is greater than or equal to 3;
? if yes, then at 128, retrieving and initializing the pressure sensor output voltage as the base voltage in real time;
o if no,
? then at 130, loading the reading of the output voltage (V) into a first variable (x1) and initiating monitoring of the odometer for retrieving an odometer reading;
? at 132, checking whether the odometer reading counter (c) is increased by 1 km in distance;
? if yes, then at 134, averaging the odometer reading for 1 km and retrieving the pressure sensor output voltage (V) value in real time, wherein the pressure sensor output voltage (V) value retrieved in real time is loaded into a second variable (x2);
? checking again, at 136, whether the odometer reading is increased by 1 km in distance;
? if yes, then at 138, averaging the odometer reading for 1 km and retrieving the pressure sensor output voltage (V) value in real time, wherein the value initially loaded into x1 is discarded and the value of x2 is moved into x1, and x2 is loaded with the current pressure sensor output voltage (V) value retrieved in real time;
? at 140, continuing averaging and retrieving at least two consecutive averages corresponding to the first variable (avg-x1) and the second variable (avg-x2) ;
? at 142, checking whether the difference (avg-x1 – avg-x2) is greater than 15 mV, wherein the value of x2 is retrieved in real time, and moving the value of x2 into x1;
o if yes, at 144, resetting the odometer reading counter (c) to zero and go to step 132;
o if no, at 146, incrementing the odometer reading counter (c), and continuing averaging the odometer reading and further incrementing the odometer reading counter (c) till four consecutive average values of x1 and x2 are retrieved and compared;
? at 148, checking whether the odometer reading counter (c) is greater than or equal to 4; and
? if yes, at 150, displaying a fuel symbol and an error message on a LCD screen, wherein the fuel symbol blinks at a rate of 1 blink per sec.

TECHNICAL ADVANCES AND ECONOMICAL SIGNIFICANCE
The technical advancements of an auto-calibrated sensor based system and method for fuel monitoring in automobiles envisaged by the present disclosure include the realization of:
• an auto-calibrated sensor based system and method for fuel monitoring in automobiles;
• a system that utilize a pressure sensor for measuring fuel in a fuel tank of the automobile;
• a system that automatically calibrates the pressure sensor;
• a system that is capable of accurately measuring the fuel in the fuel tank by calibrating the pressure sensor;
• a system that is capable of eliminating factors governed by atmospheric conditions which introduce errors in a speedometer reading of the automobile; and
• a system that can be easily interfaced with an existing non-conventional fuel tank of an automobile.
Throughout this specification the word “comprise”, or variations such as “comprises” or “comprising”, will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.
The use of the expression “at least” or “at least one” suggests the use of one or more elements or ingredients or quantities, as the use may be in the embodiment of the disclosure to achieve one or more of the desired objects or results.
Any discussion of documents, acts, materials, devices, articles or the like that has been included in this specification is solely for the purpose of providing a context for the disclosure. It is not to be taken as an admission that any or all of these matters form a part of the prior art base or were common general knowledge in the field relevant to the disclosure as it existed anywhere before the priority date of this application.
The numerical values mentioned for the various physical parameters, dimensions or quantities are only approximations and it is envisaged that the values higher/lower than the numerical values assigned to the parameters, dimensions or quantities fall within the scope of the disclosure, unless there is a statement in the specification specific to the contrary.
While considerable emphasis has been placed herein on the components and component parts of the preferred embodiments, it will be appreciated that many embodiments can be made and that many changes can be made in the preferred embodiments without departing from the principles of the disclosure. These and other changes in the preferred embodiment as well as other embodiments of the disclosure will be apparent to those skilled in the art from the disclosure herein, whereby it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the disclosure and not as a limitation. ,CLAIMS:1. A method for fuel monitoring in a fuel tank of an automobile, the method comprising:
• checking, using a control unit, whether time (t) greater than or equal to a predetermined time period lapsed after the ignition of an engine of the automobile;
• if yes, initiating sampling of an output voltage using a sensor based system having one or more pressure sensors disposed inside the fuel tank;
• checking an output voltage (V) of at least one pressure sensor of the sensor based system, wherein the control unit checks whether the sensor output voltage (V) is less than a predetermined value, and initializing an odometer reading counter (c);
o if the sensor output voltage (V) is less than a predetermined value,
? loading the reading of the output voltage (V) into a first variable (X1) and initiating monitoring of the odometer for retrieving an odometer reading;
? checking whether the odometer reading counter (c) is increased by a predetermined value in distance;
? if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the sensor output voltage (V) value retrieved in real time is loaded into a second variable (X2);
? continuing averaging and retrieving at least two consecutive averages corresponding to the first variable (avg-X1) and the second variable (avg-X2);
? checking whether a difference of the averages of the first and second variables (avg-X1 – avg-X2) is greater than a predetermined value, wherein the value of X2 is retrieved in real time, and moving the value of X2 into X1;
o if yes, resetting the odometer reading counter (c) to zero and checking whether the odometer reading counter (c) increased by the predetermined value in distance;
o if no, incrementing the odometer reading counter (c) and continuing averaging the odometer reading and further incrementing the odometer reading counter (c) till three consecutive average values of X1 and X2 are retrieved and compared;
? checking whether the odometer reading counter (c) is greater than or equal to three;
? if yes, retrieving and initializing the sensor output voltage as the base voltage in real time;
o if the sensor output voltage (V) is greater than the predetermined value,
? loading the reading of the output voltage (V) into a first variable (x1) and initiating monitoring of the odometer for retrieving an odometer reading;
? checking whether the odometer reading counter (c) is increased by a predetermined value in distance;
? if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the sensor output voltage (V) value retrieved in real time is loaded into a second variable (x2);
? continuing averaging and retrieving at least two consecutive averages corresponding to the first variable (avg-x1) and the second variable (avg-x2) ;
? checking whether a difference of the averages of the first and second variables (avg-x1 – avg-x2) is greater than a predetermined value, wherein the value of x2 is retrieved in real time, and moving the value of x2 into x1;
o if yes, resetting the odometer reading counter (c) to zero and checking whether the odometer reading counter (c) increased by the predetermined value in distance;
o if no, incrementing the odometer reading counter (c), and continuing averaging the odometer reading and further incrementing the odometer reading counter (c) till four consecutive average values of x1 and x2 are retrieved and compared;
? checking whether the odometer reading counter (c) is greater than or equal to four; and
? if yes, displaying a fuel symbol and an error message on a LCD screen.
2. The method as claimed in claim 1 further comprising:
? checking at least one more time, whether the odometer reading is increased by the predetermined value in distance in distance; and
? if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the value initially loaded into X1 is discarded and the value of X2 is moved into X1, and X2 is loaded with the current sensor output voltage (V) value retrieved in real time.
3. The method as claimed in claim 1 further comprising:
? checking at least one more time, whether the odometer reading is increased by the predetermined value in distance; and
? if yes, averaging the odometer reading for the predetermined value in distance and retrieving the sensor output voltage (V) value in real time, wherein the value initially loaded into x1 is discarded and the value of x2 is moved into x1, and x2 is loaded with the current sensor output voltage (V) value retrieved in real time.
4. The method as claimed in claim 1, wherein the predetermined value in distance is 1km.
5. The method as claimed in claim 1, wherein the predetermined value of the pressure sensor output voltage (V) is 1.38Volt.
6. The method as claimed in claim 1, wherein the difference (avg-X1 – avg-X2) of 15 mV is considered as a positive condition for auto-calibration.
7. The method as claimed in claim 1, wherein the predetermined time period is 15 seconds.
8. The method as claimed in claim 1, wherein the fuel symbol blinks at a rate of 1 blink per sec.