FORM 2
THE PATENTS ACT 1970 [39 OF 1970]
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10; rule 13]
Title: “A SYSTEM FOR MEASURING FUEL CONSUMPTION IN A VEHICLE AND
METHOD THEREOF”
Name and address of the Applicant:
TATA MOTORS LIMITED, an Indian company having its registered office at Bombay House, 24 Homi Mody Street, Hutatma Chowk, Mumbai 400 001, Maharashtra, India
Nationality: India
The following specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
Embodiments of the disclosure are related to measurement of fuel consumption by fuel flow meter on motor vehicles and more particularly system and methodology for measurement of fuel consumption on motor vehicles with diesel engine.
BACKGROUND
Traditionally the fuel consumed by the motor vehicle is calculated by monitoring the level of fuel in the reservoir, but the accuracy of measurement of fuel consumed in these methods is very poor because the level varies due to gradient of the road and other external factors.
There is a need in the operation of motor vehicles to determine the rate of fuel consumption. In order to measure the fuel consumption, turbine flow meters are installed in fuel flow lines, one in suction line and another in the return line to get the differential fuel flow in the circuit.
Internal combustion engines are used to power the automobiles, these engines can be categorized based on the type of fuel being used such as diesel engine, petrol engine or gasoline engine. In case of petrol or gasoline engine the return flow of the fuel in fuel circuit is very minimal, but in case of diesel engine return flow of the diesel is substantial. In case of petrol or gasoline engine measurement of the fuel flow through suction line is sufficient to know the amount of fuel consumed during engine running. In case of motor vehicles powered by diesel engine the return fuel flows from the engine to the main reservoir. In such cases it is obvious that, to find the actual fuel consumed by the motor vehicle there is need to meter the fuel flow from supply line as well as return line. The difference between these two lines is taken as the actual fuel consumed by the engine. In this type of method the accuracy of the fuel flow measurement is very poor, since, fuel flowing back from the engine to reservoir through return line is combination of liquid and vapor form of the diesel, this leads to the inaccuracy in measurement of fuel flow through return line.
Different fuel-circuits are possible with different fuel flow measurement principles / methods. Some fuel meters also feature fuel control as well as fuel flow measurement. Traditionally fuel meters have been built using mechanical principles such as turbine and positive displacement (pd meters). Main purpose of the Fuel-Flow-Meter on vehicles is to

measure amount of fuel consumed by the engine over certain period of time. Typically this time slot of fuel measurement can be from 1 mili-second to 1 hour.
This fuel consumption data is further used to find out various instantaneous and cumulative parameters of interest like fuel consumed per kilo-meter, fuel consumed per 100 kilo-meter, fuel consumed by vehicle for particular trip, total distance traveled by vehicle in 1 Lt of fuel (KMPL), projected KMPL value based on fuel consumed and distance traveled in last 5 seconds, etc.
Any small error in fuel measurement produces large variation in other output-data which leads to confusion and misinterpretation.
For research and development purpose methodology of fuel consumption on motor vehicles is established; in this methodology fuel flow meter is installed in the supply line, return line from the source or engine is connected back to supply line past the fuel flow meter. In this method the fuel passed past fuel flow meter doesn’t get back to the main fuel tank or main reservoir. Such kind of arrangement is widely accepted for doing trials only for the limited period; as the return fuel from engine is at elevated temperature which gets mixed with supply line, this causes the overall rise in the temperature which is going to the engine. This condition is not favorable for getting the optimum engine performance, rise in the supply fuel to engine results in the power drop. Power drop during vehicle running condition phenomenon is highly undesirable. Commercially this system is not viable.
SUMMARY OF THE DISCLOSURE
The shortcomings of the prior art are overcome and additional advantages are provided through the provision of a system as described in description.
Additional features and advantages are realized through the techniques of the present disclosure. Other embodiments and aspects of the disclosure are described in detail herein and are considered a part of the claimed disclosure.
Challenge lies in how the fuel circuit is devised to enable the measurement of fuel flow through only suction line. The fuel circuit described in this disclosure enables to reconnect the return fuel line to main suction line there by re-circulating the fuel that has passed through fuel flow meter. Also certain issues of power loss or power drop due to

increased temperature of fuel entering the FIP are overcome by providing the cooling device in the circuit, issue of fuel starvation by engine on grades is also overcome by ensuring positive fuel flow through circuit without increasing the system pressure inside the circuit by providing the over flow line to main tank through pressure relieving valve. The technology elaborated in the present disclosure eliminates the fuel flow meter in the return line and improves the accuracy of measurement.
An exemplary embodiment provides a system arranged for measuring fuel consumption in a vehicle by connecting return fuel line to main fuel supply line through an auxiliary tank (6) and thereby re-circulating the fuel that has passed through fuel flow meter (5), wherein said auxiliary tank (6) is configured to control temperature of the fuel being supplied to engine fuel circuit (7).
Another exemplary embodiment provides a system for measuring fuel consumption in a vehicle, said system comprises a feed pump (4) being configured to draw fuel out of fuel tank (1) and supplying it to engine fuel circuit (7) through a fuel strainer (2) and/or pressurise the fuel from said fuel tank (1) for maintaining predetermined pressure and flow requirement of said fuel circuit (7); damping and pressure control unit (3) configured to dampen pulsation generated in the fuel before supplying it to an auxiliary tank (6) through a flow meter (5) and for maintaining the predetermined pressure and flow requirement specified by an engine fuel circuit (7); and the flow meter (5) for measuring flow of the fuel from said tank (1) to said engine fuel circuit (7) through said auxiliary tank (6), wherein said auxiliary tank (6) is configured to control temperature of the fuel being supplied to said engine fuel circuit (7).
In an exemplary embodiment, the feed pump (4) is selected from a group comprising positive displacement pump, electrical feed pump and mechanical feed pump.
In an exemplary embodiment, the damping and pressure control unit (3) has at least one input line from the feed pump (4) and at least two output feed lines in which one feed line (OP1) is connected to said flow meter (5) and another feed line or overflow line (OP2) is connected to the fuel tank (1) through pressure relieving valve.
In an exemplary embodiment, the feed line (OP1) is always in open condition and the feed line (OP2) is opened at preset pressure.

In an exemplary embodiment, the auxiliary tank (6) has at least two inlets to receive fuel from the fuel tank (1) and the engine fuel circuit (7) and at least one outlet connected to said engine fuel circuit (7) to supply the fuel.
Another exemplary embodiment provides a method of measuring fuel consumption in a vehicle, said method comprising acts of pumping and/or pressurising the fuel from a fuel tank (1) using feed pump (4) for maintaining predetermined pressure and flow requirement of engine fuel circuit (7); dampening excessive pulsation present in the pressurised fuel before supplying it to an auxiliary tank (6) through a flow meter (5); receiving dampened fuel into the flow meter (5) for measuring flow of the fuel from said fuel tank (1) to said engine fuel circuit (7) through said auxiliary tank (6); and controlling temperature of the fuel before supplying to said engine fuel circuit (7) by mixing the fuel received from the fuel tank (1) through said flow meter (5) with the fuel received from said engine fuel circuit (7) in said auxiliary tank (6).
Another exemplary embodiment provides a method of assembling a system used for measuring fuel consumption in a vehicle, said method comprising acts of connecting feed pump (4) to a fuel tank (1) through a fuel strainer (2) using fuel supply line; connecting output line of said feed pump (4)to input line of damping and pressure control unit (3) wherein output lines of said unit (3) are connected to fuel flow meter (5) and said fuel tank (1); connecting output line of said flow meter (5) to one of the input line of an auxiliary tank (6); and connecting output line of said auxiliary tank (6) to an engine fuel circuit (7).
The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The invention itself, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings. One or more embodiments are now described, by way of example only, with

reference to the accompanying drawings wherein like reference numerals represent like elements and in which:
FIG. 1 is an exemplary diagram which illustrates fuel system layout on the rail of vehicle
FIG. 2 illustrates an exemplary diagram which shows integrated unit consists of small reservoir (1), feed pump (3) or component or device for raising, compressing or transferring the fluid, fuel strainer (2), damping and pressure reliving system (4), fuel metering device (5) or flow meter.
FIG. 3 is an exemplary diagram which shows the exploded view of integrated unit of FIG. 2.
FIG. 4 illustrates an exemplary schematic diagram of the fuel Circuit used in embodiments of the present disclosure.
FIG 5 is an exemplary diagram which shows alternative embodiment of present disclosure illustrating an arrangement of the auxiliary tank (6) inside the main fuel tank (1).
The figures depict embodiments of the disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION
The foregoing has outlined rather broadly the features and technical advantages of the present disclosure in order that the detailed description of the disclosure that follows may be better understood. Additional features and advantages of the disclosure will be described hereinafter which form the subject of the claims of the disclosure. It should be appreciated by those skilled in the art that the conception and specific embodiment disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the disclosure as set forth in the appended claims. The novel features which are believed to be characteristic of the disclosure, both as to its organization and method of operation, together with further objects

and advantages will be better understood from the following description when considered in connection with the accompanying figures. It is to be expressly understood, however, that each of the figures is provided for the purpose of illustration and description only and is not intended as a definition of the limits of the present disclosure.
An embodiment of the present disclosure is directed to overcome one or more problems as set forth. In one aspect of the disclosure, this is accomplished in an engine or combustion device having a fuel supply means for measuring fuel consumption in a vehicle by reconnecting the return fuel line to main suction line and there by re-circulating the fuel which is passed through fuel flow meter. In another aspect of the disclosure, certain issues of power loss or power drop due to increased temperature of fuel entering the FIP are overcome by providing the cooling device in the circuit. Further aspect of the disclosure, the issue of fuel starvation by engine on grades is also overcome by ensuring positive fuel flow through circuit without increasing the system pressure inside the circuit by providing the over flow line to main tank through pressure relieving valve. This invention eliminates the fuel flow meter in the return line and improves the accuracy of measurement.
The technology described in this disclosure is the fuel circuit which overcomes the limitations described in above paragraphs.
Fig. 1 shows the overall schematic circuit of the fuel system. Main fuel tank (1) or reservoir stores the fuel and is of larger capacity which is normally mounted on the chassis frame. Supply line connection is taken out from the main fuel tank (1) and is connected to small fuel strainer (2). Fuel strainer (2) removes the impurities in the form of fine particles present in the fuel and passes the clean fuel in the forward circuit. Supply from the fuel strainer (2) is given to feed Pump (3). The feed pump (3) including but not limited to positive displacement pump or electrical feed pump or mechanical feed pump. The feed pump (3) is used to meet the pressure and flow requirement of the fuel circuit laid down by the engine/fuel injection pump manufacturer.
Further, fuel circuit needs to be protected from the excessive pressure build up because of continues supply of the pressurized fuel from feed pump (3). Also fuel supplied from the feed pump (3) oscillates because of the higher pressure in the line, such pulsation is not desirable for the correct metering of the fuel by fuel flow meter (5). Hence it needs to be damped before supplying to the flow meter (5).

Damping and Pressure unit (4) is tuned to pressure reliving value based on the requirement. This unit has one input line from the feed pump (3) and two output lines. Out of these, one output line (OP1) is in always open condition and connection of this output line is connected to the flow meter (5). Other output line (OP2) which is opened at the set pressure is connected to main fuel tank (1). This enables to relive the fuel circuit from un-desired extra pressure and by pass the unwanted quantity of fuel to main fuel tank (1). Connection from flow meter (5) is given to the auxiliary reservoir (6) cum temperature control unit. Auxiliary tank (6) has two inlets and one outlet. Connection from auxiliary tank (6) is given to engine fuel circuit (7).
As described hereinabove diesel engines have the substantial return flow, return fuel flow from the engine is connected to the auxiliary tank (6). The main function of the auxiliary tank is to mix the cold fuel from main fuel tank (1) and the hot fuel from the engine there by controlling the temperature of the fuel getting supplied to engine. Return fuel flow from engine is combination of the liquid fuel as well as the fuel in the vapor form, hence there is need to condense the vapor form fuel. Vapor form fuel or air bubbles in the supply line to engine are highly undesirable for the engine running, as these air bubbles cause the air lock inside the cylinder and thereby engine doesn’t start.
Thus, auxiliary tank (6) takes care of the excessive temperature of the return fuel by doing the function of heat exchanger; also it circulates the fuel in the close circuit which is getting metered by the fuel flow meter (5). Damping and Pressure reliving unit (4) dampens the pulsation in the supply line and takes care of pressure and flow requirements specified by the engine or fuel injection pump manufacturer.
The Auxiliary tank (6) is a simple reservoir made out of good thermal conductivity material such as steel, aluminum copper or any other material compatible to the diesel fuel with higher thermal conductivity. Heat dissipation from the auxiliary tank (6) is achieved through conduction, convection and radiation, because of the mixing of the hot and cold fuel under pressure inside the tank (6) causes turbulence, by this effect heat gets transferred from fuel to the metal body of the tank (6). Heat dissipation from the auxiliary tank (6) takes place by natural air draft of the air because of the vehicle speed, the effect of air draft can be strengthened by giving the aid of deflectors in order to direct the air draft on the tank.

Cooling of the tank (6) can also be achieved by giving the effect of forced air draft by means of blower or fan.
The auxiliary tank effect can also be achieved using alternative embodiments. One of such embodiments is explained herein below for illustrative purpose only. However, it cannot be construed as limitation on the scope of the instant technology.
Main fuel tank is normally has the compartments which are separated by the perforated baffles. These baffles minimize the effect of surging effect during the braking and acceleration of the vehicle. Normally main fuel tank has more than one compartment. Effect of auxiliary tank can also be achieved by isolating the compartment which is on the vehicle front side with baffle without any perforations in it. The auxiliary tank (6) is inbuilt in said main fuel tank (1). The alternative arrangement of auxiliary tank (6) inside the main fuel tank (6) is diagrammatically illustrated in fig. 5.
Fig. 2 shows the mounting arrangement of fuel tank (1) on the chassis frame, fuel strainer (2) and the integrated unit (8).
Fig. 3 and Fig. 4 show the arrangement of components on integrated unit (8). Integrated unit is an add-on unit which is in itself plumbed unit of feed pump (3). Connection from feed pump (3) is given to damping and pressure control unit (4), one output is left open for connection back to main fuel tank (1). Always open connection from damping unit (4) is connected to the fuel flow meter (5). Connection from the fuel flow meter (5) is given to auxiliary tank (6). The integral unit (8) is made for the ease of the packaging.
The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its spirit and scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods, reagents, compounds compositions or biological systems, which can, of

course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.
With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity.
It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., “a” and/or “an” should be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “ a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would

understand the convention (e.g., “ a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.”
In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.
While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims

Table 1 - List of numerals

Numeral number Description
1 Fuel Tank
2 Fuel Strainer
3 Feed Pump
4 Damping and Pressure Control Unit
5 Fuel Flow Meter
6 Auxiliary Tank
7 Engine Fuel Circuit
8 Integrated Unit

We Claim:
1. A system for measuring fuel consumption in a vehicle by connecting return fuel line to main fuel supply line through an auxiliary tank (6) and thereby re-circulating the fuel that has passed through fuel flow meter (5), wherein said auxiliary tank (6) is configured to control temperature of the fuel being supplied to engine fuel circuit (7).
2. A system for measuring fuel consumption in a vehicle, said system comprises
i. feed pump (4) being configured to draw fuel out of fuel tank (1) and supplying it to engine fuel circuit (7) through a fuel strainer (2) and/or pressurise the fuel from said fuel tank (1) for maintaining predetermined pressure and flow requirement of said fuel circuit (7);
ii. damping and pressure control unit (3) configured to dampen pulsation generated in the fuel before supplying it to an auxiliary tank (6) through a flow meter (5) and for maintaining the predetermined pressure and flow requirement specified by an engine fuel circuit (7); and
iii. the flow meter (5) for measuring flow of the fuel from said tank (1) to said engine fuel circuit (7) through said auxiliary tank (6), wherein said auxiliary tank (6) is configured to control temperature of the fuel being supplied to said engine fuel circuit (7).
3. The system as claimed in claim 2, wherein the feed pump (4) is selected from a group comprising positive displacement pump, electrical feed pump and mechanical feed pump.
4. The system as claimed in claim 2, wherein the damping and pressure control unit (3) has at least one input line from the feed pump (4) and at least two output feed lines in which one feed line (OP1) is connected to said flow meter (5) and another feed line or overflow line (OP2) is connected to the fuel tank (1) through pressure relieving valve.
5. The system as claimed in claim 4, wherein the feed line (OP1) is always in open condition and the feed line (OP2) is opened at preset pressure.
6. The system as claimed in claims 1 and 2, wherein the auxiliary tank (6) has at least two inlets to receive fuel from the fuel tank (1) and the engine fuel circuit (7) and at least one outlet connected to said engine fuel circuit (7) to supply the fuel.

7. The system as claimed in claims 1 and 2, wherein said auxiliary tank (6) is inbuilt in said main fuel tank (1).
8. The system as claimed in claims 1 and 2, wherein the auxiliary tank (6) is made of thermal conductive materials selected from a group comprising steel, aluminium, copper and any other material compatible to the diesel fuel with thermal conductivity.
9. A method of measuring fuel consumption in a vehicle, said method comprising acts of
i. pumping and/or pressurising the fuel from a fuel tank (1) using feed pump (4) for maintaining predetermined pressure and flow requirement of engine fuel circuit (7);
ii. dampening excessive pulsation present in the pressurised fuel before supplying it to an auxiliary tank (6) through a flow meter (5);
iii. receiving dampened fuel into the flow meter (5) for measuring flow of the fuel from said fuel tank (1) to said engine fuel circuit (7) through said auxiliary tank (6); and
iv. controlling temperature of the fuel before supplying to said engine fuel circuit (7) by mixing the fuel received from the fuel tank (1) through said flow meter (5) with the fuel received from said engine fuel circuit (7) in said auxiliary tank (6).
10. The method as claimed in claim 9, wherein heat dissipation from the auxiliary tank (6) takes place by natural air draft, wherein effect of the air draft is strengthened with the help of deflectors in order to direct the air draft on the tank (6), and/or the effect of forced air draft is achieved by means of blower or fan.
11. A method of assembling a system used for measuring fuel consumption in a vehicle, said method comprising acts of
i. connecting feed pump (4) to a fuel tank (1) through a fuel strainer (2) using fuel
supply line; ii. connecting output line of said feed pump (4)to input line of damping and pressure
control unit (3) wherein output lines of said unit (3) are connected to fuel flow
meter (5) and said fuel tank (1); iii. connecting output line of said flow meter (5) to one of the input line of an auxiliary
tank (6); and

iv. connecting output line of said auxiliary tank (6) to an engine fuel circuit (7).
12. A system and method for measuring fuel consumption in a vehicle is substantially as herein above described and as illustrated with reference to the accompanying drawings.