FORM-2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See section 10 and rule 13)
FUEL GAUGE SYSTEM FOR VEHICLES
MAHINDRA TWO WHEELERS LIMITED
an Indian Company
of Dl Block, Plot No. 18/2 (Part),
M1DC, Chinchwad, Pune - 411 019,
Maharashtra, India.
Inventors:
1. VENKATRAMAN YOGARAJA
2. SOLAIDEVAR LAKSHMANAN
3. SUNDARAM SUDHARSAN
4. JASTI KIRANKUMAR
5. SHENDE RAMKRUSHNA
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE NATURE OF THEINVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.

FIELD OF THE DISCLOSURE
The present disclosure relates to fuel gauge systems for vehicles.
BACKGROUND
A fuel gauge is used to indicate fuel level in the fuel tank of a vehicle. A fuel gauge system has two parts, namely a sensing unit and an indicating unit. The sensing unit usually uses a float connected to a potentiometer. With the decreasing fuel level in the fuel tank, the float drops and slides a moving contact along a resistor, thereby increasing resistance of the resistor. Meanwhile, the indicator unit measures and displays the amount of electrical current flowing through a sensing unit. When the fuel tank level is high, maximum current flows and the needle points to "F" indicating a full tank. When the fuel tank is empty, least current flows, the needle points to "E" indicating an empty tank. Fuel gauges of such type have low accuracy; therefore driver of the vehicle does not get exact information of the volume of fuel remaining in the fuel tank of the vehicle.
Conventional fuel gauge systems are limited by their accuracy and sensitivity. Such fuel gauge systems use low number of resistors typically 10 to 15 number of resistors in a film resistance for detecting change in fuel volume of fuel held inside the fuel tank of a vehicle. Such fuel gauge systems are also limited by the degree of float movement; typically such fuel gauge systems have float movement limited to 3 to 4 degrees with a single track which limits conventional fuel gauge systems from detecting change fuel volume of fuel held inside the tank, particularly, for a tank of capacity 14 litres the conventional fuel gauge system can detect change in fuel volume for every litre volume of fuel. Further such fuel gauge systems are not sensitive detecting change in fluid

volume in the fluid tank and as such the conventional fuel gauge systems fail to provide accurate dynamic inputs to other systems having certain advanced features such as 'distance to empty' (DTE) systems, thereby failing in utilizing capabilities of such systems.
There is thus felt a need to provide a fuel gauge system that works effectively and efficiently with increased sensitivity to indicate volume of fuel remaining in a fuel tank of a vehicle. There is also felt a need to provide a fuel gauge system that is reliable and cost effective.
OBJECTS
Some of the objects of the present disclosure 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 disclosure is to provide a fuel gauge system that is accurate.
Another object of the present disclosure is to provide a fuel gauge system that indicates a distance a vehicle can travel using fuel remaining in a fuel tank of a vehicle.
Yet another object of the present disclosure is to provide a fuel gauge system that fits into a conventional fuel tank of a vehicle.
An additional object of the present disclosure is to provide a fuel gauge system that is comparatively more sensitive.

Another object of the present disclosure is to provide a fluid gauge system that operate in conjunction with a control module of a "distance to empty" system to dynamically provide input in form of fluid level to the "distance to empty" system for facilitating operation of the "distance to empty system" for receiving output from the distance to empty system.
Still another object of the present disclosure is to provide a fuel gauge system that is cost effective.
An additional object of the present disclosure is to provide a fuel gauge system that is reliable.
Other objects and advantages of the present disclosure will be more apparent from the following description when read in conjunction with the accompanying figures, which are not intended to limit the scope of the present disclosure.
SUMMARY
A fluid gauge system for indicating fluid level inside a fluid tank is disclosed in accordance with an embodiment of the present disclosure. The fluid gauge system includes a float, at least one moving contact and a sensor module. The float floats on a surface of fluid contained inside the fluid tank and moves up and down as fluid level inside the fluid tank changes. The moving contact is functionally coupled to the float and moves along an arcuate path as the float moves. The sensor module is having a resistance plate with a plurality of resistors disposed on the resistance plate and arranged along an arcuate profile complimentary to the arcuate path followed by the moving contact such that the plurality of resistors co-operates with the moving contact to establish a spring biased contact between the moving contact and a particular resistor of the

plurality of resistors to set up an electrical circuit corresponding to a level of the float and therefore corresponding to a particular level of fluid inside the fluid tank, wherein the fluid gauge system is adapted to detect change in fluid volume in the fluid tank in the range of 50 to 250 ml.
Typically, the fluid gauge system detects every 100 ml change in fluid volume in the fluid tank.
Generally, the sensor module is a Thick Film Resistance (TFR) module that includes a thick film resistance plate with a plurality of resistors arranged along the arcuate profile.
Alternatively, the sensor module includes resistors selected from a group consisting of Thin Film Resistance, a linear resistor and a winding resistance.
Typically, the sensor module further includes a ground reference.
Generally, the plurality of resistors are arranged along the arcuate profile at an angular spacing in the range of 0.2 to 1 degree, wherein number of the plurality of resistors is in the range of 80 to 90.
Further, the fluid gauge system includes a holder mounted inside said fuel tank for holding said sensor module.
Alternatively, the fluid gauge system includes an arcuate holder mounted inside the fuel tank for holding the sensor module.
In accordance with one embodiment, the fluid gauge system further includes a lever and a wiper, the wiper is mounted on the lever, wherein one end of the lever is connected to the float and the other end of the lever is pivotally connected to the arcuate holder, the at least one moving contact mounted on the

wiper moves along the arcuate path as the lever pivots about a pivot as the float moves to establish a spring biased contact between the at least one moving contact and a particular resistor of the plurality of resistors to set up an electrical circuit corresponding to a level of the float and therefore corresponding to a particular level of fluid inside the fluid tank.
In accordance with another embodiment, the fluid gauge system includes a lever and a roller body, the lever is connected to the float, the roller body is mounted on the lever and is in rolling contact with the resistance plate mounted on the arcuate holder as the float moves to establish a spring biased contact between the at least one moving contact mounted on the roller body and a particular resistor of the plurality of resistors to set up an electrical circuit corresponding to a level of the float and therefore corresponding to a particular level of fluid inside the fluid tank.
Further, the fluid gauge system is functionally coupled to a control module of a distance to empty system to dynamically provide input in the form of fluid level to the distance to empty system and facilitate operation of the distance to empty system for receiving output from the distance to empty system.
BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS
The fuel gauge system of the present disclosure will now be described with the help of accompanying drawings, in which:
FIGURE 1 illustrates an isometric view of a fluid gauge system in accordance with an embodiment of the present disclosure;

FIGURE 2 illustrates a front view of a sensor module of the fluid gauge system of FIGURE 1;
FIGURE 3 illustrates a front view of a thick film resistance plate of the sensor module of FIGURE 2;
FIGURE 4 illustrates a schematic representation of mounting arrangement for mounting the fuel gauge system of FIGURE 1 on to a fuel tank of a vehicle;
FIGURE 5 illustrates an isometric view of a fluid gauge system in accordance with an embodiment of the present disclosure;
FIGURE 6 illustrates an enlarged view depicting interaction of the roller body with the arcuate holder; and
FIGURE 7 illustrates a block diagram depicting an interaction of the fluid gauge system of FIGURE 1 with a control module of a distance to empty system to dynamically provide input in form of fluid level to the distance to empty system and facilitating operation of the distance to empty system for receiving output from the distance to empty system.
DETAILED DISCRIPTION OF THE ACCOMPANYING DRAWINGS
A preferred embodiment will now be described in detail with reference to the accompanying drawings. The preferred embodiment does not limit the scope and ambit of the disclosure. The description provided is purely by way of example and illustration.

The embodiment herein and the various features and advantageous details thereof are explained with reference to the non-limiting embodiment in the following description. Description of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiment herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiment herein may be practiced and to further enable those of skill in the art to practice the embodiment herein. Accordingly, the example should not be construed as limiting the scope of the embodiment herein.
The following description of the specific embodiment will so fully reveal the general nature of the embodiment 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 embodiment. 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 embodiment herein has been described in terms of the preferred embodiment, those skilled in the art will recognize that the embodiment herein can be practiced with modification within the spirit and scope of the embodiment as described herein.
The fuel gauge system of the present disclosure will now be explained with reference to FIGURES 1 to FIGURE 6 with the key components being generally referenced by numerals, alphabets and alpha numerals as illustrated. The fuel gauge system of the present disclosure envisages a solution to overcome the drawbacks of the prior art. The fuel gauge system is sensitive and detects changes in fluid volume in the fluid tank in the range of 50 to 250 ml. More particularly, the fuel gauge system detects every 100 ml change in fluid

volume in the fluid tank. Such fuel gauge system dynamically provides input in form of fluid level to the "distance to empty" system and facilitates in efficient operation of the "distance to empty" system for receiving accurate output from the distance to empty system, particularly, the accurate calculations for distance a vehicle can travel using the fuel remaining in the tank of the vehicle. The "distance to empty" feature is usually provided in vehicles where fuel injection system exists.
The fuel gauge system 100 in accordance with an embodiment of the present disclosure is illustrated in FIGURE 1. The fuel gauge system 100 includes a float "F", at least one moving contact "C" and a sensor module "X". The float "F" floats on a surface of fluid contained inside the fluid tank (illustrated in FIGURE 3) and moves up and down as fluid level inside the fluid tank changes. The at least one moving contact "C" is functionally coupled to the float "F" and moves along an arcuate path as the float "F" moves. The sensor module "X" is having a resistance plate with a plurality of resistors disposed on the resistance plate and arranged along an arcuate profile complimentary to the arcuate path followed by the at least one moving contact "C" such that the plurality of resistors co-operates with the at least one moving contact "C" to establish a spring biased contact between the at least one moving contact "C" and a particular resistor of the plurality of resistors to set up an electrical circuit corresponding to a level of the float "F" and therefore corresponding to a particular level of fluid inside the fluid tank. The sensor module is either one of a Thick Film Resistance (TFR) module, a Thin Film Resistance (TFR) module, a linear resistor and a winding resistance module. The fluid gauge system 100 further includes a holder "H" mounted inside the fuel tank for holding the sensor module "X". More specifically, the fluid gauge system 100 includes an arcuate holder "H" mounted inside the fuel tank for holding the sensor module.

The holder "H" is mounted inside the fuel tank using a mounting plate "M" that is mounted on the fuel tank using bolts or other fasteners.
Referring to FIGURE 1 - Figure 3, the fuel gauge system 100 includes a lever "L" and a wiper "W" for facilitating in establishing a spring biased contact between at least one moving contact "C" and a particular resistor of a plurality of resistors 102 arranged along an arcuate profile on a resistance plate 110 and mounted on the arcuate holder "H" to set up an electrical circuit corresponding to a level of the float "F" and therefore corresponding to a particular level of fluid inside the fluid tank.
Referring to FIGURE 2 and FIGURE 3, the sensor module "X" includes the resistance plate 110 mounted on the holder "H", the plurality of resistors 102 arranged along the arcuate profile on the resistance plate 110 and a ground reference 108. For accurate measurement of volume of fuel inside the tank of the vehicle, the fuel gauge system 100 utilizes a highly accurate Thick Film Resistance (TFR) plate. However, instead of Thick Film Resistance (TFR) other resistances such as Thick Film Resistance, linear resistor and a winding resistance can also be used. Due to the layout constraints of such resistances, particularly, the Thick Film Resistance (TFR), such TFR cannot be accommodated in the fuel tank and needs an appropriate construction. By using the configuration of arranging the plurality of resistors 102 on the resistance plate 110 along an arcuate profile complimentary to the arcuate path followed by the at least one moving contact, more number of resistors can be disposed in limited space, thereby improving the sensitivity of the fuel gauge system 100 in detecting changes in fluid volume in the fluid tank. More particularly, the fuel gauge system 100 detects every 100 ml change in fluid volume in the fluid tank.

Referring to FIGURE 4, a schematic representation of mounting arrangement for mounting the fuel gauge system 100 on to the fuel tank of the vehicle is illustrated. Typically, the fuel tank includes an inner portion 114 and an outer portion 116, a fuel gauge mounting arrangement in the form of an opening 112 is configured on the inner portion 114 and receives the mounting plate "M". The fuel gauge system 100 of the present disclosure is received inside the tank via the opening 112 and is mounted on the mounting plate "M". Typically, the opening 112 configured on the inner portion 114 is of 32mm diameter facilitates entry of the fuel gauge system 100 inside the fuel tank.
The accuracy and sensitivity of the fuel gauge system 100 is enhanced by use of the Thick film Resistance (TFR) plate 110, the enhanced sensitivity of the fuel gauge system 100 is achieved by the following arrangements:
increased number of resistors disposed on the Thick film Resistance (TFR) plate 110 by arranging the plurality of resistors 102 along the arcuate profile on the Thick film Resistance (TFR) plate 110 mounted on the arcuate holder "H"; and
shape of the Thick film Resistance (TFR) plate 110 and a holder "H" is modified to an arcuate shape for providing ease of accommodation of the Thick film Resistance (TFR) plate 110 of the fuel gauge system 100 in the fuel tank 200.
Further, the fuel gauge system 100 of the present disclosure is provided with a plurality of tracks. A typical range for the number of tracks provided in the fuel gauge system 100 of the present disclosure increased from 11 to 84. However, number of tracks can be increased depending upon the capacity of the tank of the vehicle. Such tracks are located in proximity to each other typically 0.5

degree apart from each other, for instance 84 resistors within 42 degrees; thereby facilitating measurement of very small volume change of fuel, typically every 100 ml of volume change of fuel inside the tank of the vehicle. Such an arrangement of the fuel gauge facilitates accommodation of the fuel gauge system 100 of the present disclosure in the fuel tank without any modification to the fuel tank with desired accuracy and also enables prediction of the DTE because of the accurate fuel measurement.
FIGURE 5 illustrates an isometric view of a fluid gauge system 200 in accordance with an embodiment of the present disclosure. Referring to FIGURE 5 - Figure 6, the fuel gauge system 200 includes a lever "L2" and a roller body "R" for facilitating in establishing a spring biased contact between at least one moving contact "C2" and a particular resistor of a plurality of resistors 202 arranged along an arcuate profile on a resistance plate 210 mounted on an arcuate holder "H2" to set up an electrical circuit corresponding to a level of a float and therefore corresponding to a particular level of fluid inside a fluid tank. The fluid gauge system 200 includes an arcuate holder "H2" mounted inside the fuel tank for holding the sensor module. The holder "H2" is mounted inside the fuel tank using a mounting plate "M2" that is mounted on the fuel tank using bolts or other fasteners. The sensor module is either one of a Thick Film Resistance (TFR) module, a Thin Film Resistance module, a linear resistor and a winding resistance module. The sensor module includes the resistance plate 210 mounted on the holder "H2", the plurality of resistors 202 arranged along the arcuate profile on the resistance plate 210 and a ground reference 208.
FIGURE 6 illustrates a side view depicting contact between the at least one moving contact "C2" and a particular resistor of the plurality of resistors 202 arranged along an arcuate profile on the resistance plate 210 mounted on the arcuate holder "H2" to set up an electrical circuit corresponding to a level of the

float and therefore corresponding to a particular level of fluid inside the fluid tank.
FIGURE 7 illustrates a block diagram 300 depicting an interaction of the fluid gauge system with a control module of a "distance to empty" system to dynamically provide input in form of fluid level to the "distance to empty" system and facilitating operation of the "distance to empty system" for receiving output from the distance to empty system.
Although, the present disclosure is described for indicating fuel levels inside a fuel tank, the present disclosure is not limited to indication of fuel levels inside a fuel tank only. The principles/ disclosure of the present disclosure can be effectively used for indicating fluid levels inside any fluid tank.
TECHNICAL ADVANCEMENTS AND ECONOMIC SIGNIFICANCE
The technical advancements offered by the present disclosure include the realization of:
• a fuel gauge system that is accurate;
• a fuel gauge system that indicates the distance a vehicle can travel using the fuel remaining in the tank of a vehicle;
• a fuel gauge system that can fit into a conventional fuel tank of a vehicle;
• a fuel gauge system with increased sensitivity;
• a fluid gauge system that operate in conjunction with a control module of a "distance to empty" system to dynamically provide input in form of fluid level to the "distance to empty" system for facilitating operation of the "distance to empty system" for receiving output from the distance to empty system;

• a fuel gauge system that is cost effective; and
• a fuel gauge system that is reliable.
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.
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.
Wherever a range of values is specified, a value up to 10% below and above the lowest and highest numerical value respectively, of the specified range, is included in the scope of the disclosure.
The foregoing description of the specific embodiment 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 embodiment 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 embodiment. 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 embodiment herein have been described in terms of preferred embodiment, those skilled in the art will recognize that the embodiment herein can be practiced with modification within the spirit and scope of the embodiment as described herein.

We Claim:
1. A fluid gauge system for indicating fluid level inside a fluid tank, said fluid gauge system comprising:
• a float adapted to float on a surface of fluid contained inside said fluid tank and adapted to move up and down as fluid level inside said fluid tank changes;
• at least one moving contact functionally coupled to said float and adapted to move along an arcuate path as said float moves; and
• a sensor module having a resistance plate with a plurality of resistors disposed on said resistance plate and arranged along an arcuate profile complimentary to said arcuate path followed by said moving contact such that said plurality of resistors are adapted to co-operate with said moving contact to establish a spring biased contact between said moving contact and a particular resistor of said plurality of resistors to set up an electrical circuit corresponding to a level of said float and therefore corresponding to a particular level of fluid inside said fluid tank, wherein said fluid gauge system is adapted to detect change in fluid volume in said fluid tank in the range of 50 to 250 ml.

2. The fluid gauge system as claimed in claim 1, is adapted to detect every 100 ml change in fluid volume in said fluid tank.
3. The fluid gauge system as claimed in claim 1, wherein said sensor module is a Thick Film Resistance (TFR) module comprising a thick film resistance plate with a plurality of resistors arranged along said arcuate profile.

4. The fluid gauge system as claimed in claim 1, wherein said sensor module comprising resistors selected from a group consisting of Thin Film Resistance, a linear resistor and a winding resistance.
5. The fluid gauge system as claimed in claim 1, wherein said sensor module further comprises a ground reference.
6. The fluid gauge system as claimed in claim 1, wherein said plurality of resistors are arranged along said arcuate profile at an angular spacing in the range of 0.2 to 1 degree, wherein number of said plurality of resistors is in the range of 80 to 90.
7. The fluid gauge system as claimed in claim 1, further comprising a holder mounted inside said fuel tank for holding said sensor module.
8. The fluid gauge system as claimed in claim 1, further comprising an arcuate holder mounted inside said fuel tank for holding said sensor module.
9. The fluid gauge system as claimed in claim 8, further comprising a lever and a wiper, said wiper is mounted on said lever, wherein one end of said lever is connected to said float and the other end of said lever is pivotally connected to said arcuate holder, said at least one moving contact mounted on said wiper adapted to move along said arcuate path as said lever pivots about a pivot as said float moves to establish a spring biased contact between said at least one moving contact and a particular resistor of said plurality of resistors to set up an electrical circuit corresponding to a level of said float and therefore corresponding to a particular level of fluid inside said fluid tank.

10.The fluid gauge system as claimed in claim 8, further comprising a lever and a roller body, said lever is connected to said float, said roller body is mounted on said lever and adapted to be in rolling contact with said resistance plate mounted on said arcuate holder as said float moves to establish a spring biased contact between said at least one moving contact mounted on said roller body and a particular resistor of said plurality of resistors to set up an electrical circuit corresponding to a level of said float and therefore corresponding to a particular level of fluid inside said fluid tank.
11 .The fluid gauge system as claimed in claim 1, further functionally coupled to a control module of a distance to empty system to dynamically provide input in the form of fluid level to said distance to empty system and facilitate operation of said distance to empty system for receiving output from said distance to empty system.