WO2014102812A1

WO2014102812A1 - A system and a method for determining distance to empty of a vehicle

Info

Publication number: WO2014102812A1
Application number: PCT/IN2013/000762
Authority: WO
Inventors: Vinten.D. DIWAKAR; Nagendra Babu Sathyanarayana; Saravanan MEENATCHISUNDARAM; Prakash Ramaraju; Syrus.R. NEDUMTHALY
Original assignee: Mahindra Reva Electric Vehicles Private Limited
Priority date: 2012-12-24
Filing date: 2013-12-10
Publication date: 2014-07-03

Abstract

A system 100 for determining Distance To Empty (DTE) of a vehicle is disclosed, said system comprises, an input means for receiving information on at least one of a real time capacity, an odometer reading, temperature, terrain or grade, state of charge of energy storage system, state of health of Energy Storage System, initial capacity of energy storage system and an initial DTE of the vehicle. Further, a control unit 102 configured for receiving information from the input means and regulate functioning of at least one of adaptive usage efficiency parameter detection unit 104, a driven distance calculating unit 106, a calibration residual calculation unit 108, a calibration residual compensated driven distance calculating unit 110 and a distance to empty calculation unit 111. Furthermore an output means for displaying information received from the control unit 102.

Description

A SYSTEM AND A METHOD FOR DETERMINING DISTANCE TO EMPTY OF A

VEHICLE

FIELD OF INVENTION

[001] This invention relates to a method and a system for computing Distance To Empty

(DTE) in vehicles, and more particularly but not exclusively to a method and a system for improving accuracy in computing Distance To Empty (DTE) in electrically powered vehicles.

BACKGROUND OF INVENTION

[002] Generally, most of the vehicles include display systems to display vehicle parameters such as vehicle speed, distance travelled and fuel left. Further, in recent years, a Distance To Empty (DTE) number has been introduced in some of the vehicles. DTE is the distance that could be theoretically travelled by the vehicle with the amount of fuel left in the vehicle. Typically, DTE value is obtained by the fuel economy of the vehicle and the amount of fuel remaining in the vehicle. DTE in an electric vehicle is the distance that could be travelled by the vehicle with the amount of usable electricity/charge remaining in the energy storage system of the vehicle. Estimating and displaying DTE in an electric vehicle is given significant importance as charging the batteries of electric vehicle requires longer times and the available capacity of on-board energy storage systems remains relatively small which reflects in limited range when compared to vehicles powered by internal combustion engines.

[003] Although displaying DTE value is proven to be useful for the user of the vehicle, it should be noted that commonly used methods of computing DTE have some drawbacks which make the computed DTE partially inefficient. For example, in conventional systems DTE is calculated based on the fuel economy of the vehicle which is a fixed value. However, fixed value of fuel economy is highly unreliable as the fuel economy varies from vehicle to vehicle, driver behavior, terrain, etc. Further, the fuel economy of the vehicle varies over a period of time and under different operating conditions. Hence, the DTE value determined by conventional methods based on fixed fuel economy is substantially different from the actual theoretical DTE.

[004] Therefore, there is a need for a system and a method to compute DTE of a vehicle by considering various real time factors that could affect DTE. Further, there is a need for a system and a method that could negate the drawbacks of conventional systems and methods for computing DTE of the vehicle.

SUMMARY

[005] Accordingly a system for determining Distance To Empty (DTE) of a vehicle is disclosed, said system comprises, an input means for receiving information on at least one of a real time capacity, an odometer reading, temperature, terrain or grade, state of charge of energy storage system, state of health of Energy Storage System, initial capacity of energy storage system and an initial DTE of the vehicle. Further, a control unit configured for receiving information from the input means and regulate functioning of at least one of adaptive usage efficiency parameter detection unit, a driven distance calculating unit, a calibration residual calculation unit, a calibration residual compensated driven distance calculating unit and a distance to empty calculation unit. Furthermore an output means for displaying information received from the control unit.

[006] Further a method for determining Distance To Empty (DTE) of a vehicle is described in another embodiment. The method comprises, receiving information by an input means on at least one of a real time capacity, an odometer reading, temperature, terrain or grade, state of charge of energy storage system, state of health of Energy Storage System, initial capacity of energy storage system and an initial DTE of the vehicle. Further, regulating function of at least one of adaptive usage efficiency parameter detection unit, a driven distance calculating unit, a calibration residual calculation unit, a calibration residual compensated driven distance calculating unit and a distance to empty calculation unit by a control unit based on the information from the input means. Furthermore, displaying the information received from the control unit by an output means. OBJECT OF INVENTION

[007] The principal object of this invention is to provide a system and a method for determining Distance To Empty (DTE) of a vehicle considering various real time factors that could affect the DTE value.

[008] Another object of the invention is to provide a system and a method that could automatically correct the DTE value based on the real time factors.

[009] A third object of the invention is to provide a system and a method that could accommodate variations within a drive with good precision without the prior need of any drive pattern data.

[0010] Another object of the invention is to provide a system and a method that produces a conservative estimate of the DTE compared to the more commonly used fuel efficiency based DTE thereby adding an extra measure of predictability especially for drives with varying harshness. [001 1] A further object of the invention is to provide a relatively simple method of DTE calculation which is easier to implement and realize.

[0012] These and other objects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating preferred embodiments and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES

[0013] This invention is illustrated in the accompanying drawings, throughout which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:

[0014] FIG. 1 is a block diagram depicting architecture of a system for determining DTE of an electrically powered vehicle according to an embodiment of the present invention;

[0015] Fig. 2 is a graph depicting correlation between the optimized capacity efficiencies and drives that have similar capacity efficiency numbers according to an embodiment of the present invention; and

[0016] FIG. 3 is a flow chart depicting a method 200 for determining DTE value for the vehicle according to an embodiment of the present invention. DETAILED DESCRIPTION OF INVENTION

[0017] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed 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. For example, it should be noted that while some embodiments are explained with respect to a system and a method for determining DTE in electrically powered vehicles, it should be noted that the system and the method as disclosed in the present invention could also be used for any other vehicles such as hybrid vehicles, vehicles powered by internal combustion engines and so on by incorporating the subject matter of the invention with little or no modifications. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

[0018] The embodiments herein achieve a system and a method for determining DTE of an electrically powered vehicle considering various real time factors that could affect the DTE value. Referring now to the drawings, and more particularly to FIGS. 1 to 3, where similar reference characters denote corresponding features consistently throughout the figures that are shown in the embodiments.

[0019] FIG. 1 is a block diagram depicting architecture of a system for determining DTE of an electrically powered vehicle according to an embodiment of the present invention. The system 100 includes a control unit 102 that is configured to be engaged with an adaptive usage efficiency parameter detection unit 104, a driven distance calculating unit 106, a calibration residual calculation unit 108, a calibration residual compensated driven distance calculating unit 1 10 and a distance to empty calculation unit 1 1 1. Further, the control unit 102 is configured to regulate functioning of at least one of the adaptive usage efficiency parameter detection unit 104, the driven distance calculating unit 106, the calibration residual calculation unit 108, the residual compensated driven distance unit 1 10 and the distance to empty calculation unit 1 1 1.

[0020] In an embodiment, the system 100 includes an input means, an output means and the control unit 102. The input means is provided with a first input module 1 12a and a second input module 1 12b. The first input module 1 12a is configured to provide information on at least one of a real time capacity of the vehicle, an odometer reading, temperature, terrain or grade, state of charge of the energy storage system of the vehicle and state of health of the energy storage system of the vehicle. Further, the second input module 1 12b is configured to provide information on an initial capacity of the energy storage system of a vehicle and an initial DTE. The information of at least one of the initial capacity of the energy storage system of the vehicle, the initial DTE, the real time capacity of the vehicle, the odometer reading, temperature, terrain or grade, the state of charge of the energy storage system of the vehicle and the state of health of the energy storage system of the vehicle is determined by conventional methods. The output means of the system 100 is provided in communication with a display or human machine interface 1 14. The display or human machine interface 1 14 is a device that could be configured to display or communicate the DTE to the user of the vehicle. The control unit 102 is configured to receive information from the first input module 1 12a and second input module 1 12b and regulate functioning of at least one of the adaptive usage efficiency parameter detection unit 104, the driven distance calculating unit 106, the calibration residual calculating unit 108, the calibration residual compensated driven distance unit 110 and the distance to empty calculation unit 111.

[0021] In an embodiment, the adaptive usage efficiency parameter detection unit 104 is configured to receive information on the real time capacity or energy or SoC of the energy storage system of the vehicle and the distance travelled from the input module 1 12a of the system 100. Further, the adaptive usage efficiency parameter detection unit is configured to determine the adaptive usage efficiency parameter in real time based on the real time capacity or energy or State of Charge (SoC) for the travelled distance and the optimized capacity or energy or SoC for the travelled distance. In an embodiment, the optimized capacity is obtained by performing controlled experiments at specific fuel efficiencies on a rolling dynamometer. Further, the adaptive usage efficiency parameter is obtained between optimized capacity efficiencies and drives that have similar capacity efficiency numbers.

Adaptive usage efficiency parameter- = ({Real-time capacity or Energy or

SoC}/{km})/({Optimized Capacity or Energy or SoC}/{km})

In an embodiment, the parameter can take the form of any mathematical function including at least one of linear, quadratic, exponential and so on. In another embodiment, the parameter is a function of the vehicle variant such as curb weight, energy storage system variations and so on. Fig. 2 is a graph depicting correlation between the optimized capacity efficiencies and drives that have similar capacity efficiency number according to an embodiment of the present invention.

[0022] In an embodiment, the driven distance calculating unit 106 is configured to receive information on the adaptive usage efficiency parameter from the adaptive usage efficiency parameter detection unit 104. Further, the driven distance calculating unit 106 is configured to receive information on the real time capacity or energy or SoC from the first input module 1 12a and the information on the initial DTE value and the initial capacity or energy or SoC of the energy storage system from the second input module 1 12b. Further, the driven distance calculating unit 106 is programmed to calculate the driven distance based on the adaptive usage efficiency parameter using the information on the real time capacity, initial capacity, initial DTE value and the adaptive usage efficiency parameter. In an embodiment, the driven distance based on adaptive usage efficiency parameter is calculated as,

Driven distance based on adaptive usage efficiency parameter in real time = {Real-time capacity/Initial Capacity}* {Initial DTE Value}* {Adaptive Usage Efficiency Parameter}.

[0023] In an embodiment, the calibration residual calculation unit 108 is configured to receive information on the driven distance based on adaptive usage efficiency parameter in real time from the driven distance calculating unit 106 and the information on the odometer driven distance from the first input module 1 12a. Further, the calibration residual unit 108 is programmed to calculate the calibration residual based on the driven distance based on adaptive usage efficiency parameter in real time and the odometer driven distance. In an embodiment, the calibration residual is calculated as the square of the difference between the driven distance based on adaptive usage efficiency parameter in real time and the odometer driven distance.

Calibration residual = {Driven distance based on adaptive usage efficiency parameter in real time - Distance Driven from odometer}²

[0024] In an embodiment, the calibration residual compensated driven distance unit 1 10 is configured to receive information on the real time capacity of the energy storage system from the first input module 1 12a, information on the initial DTE value and the initial capacity of the energy storage system from the second input module 1 12b and the information on the calibration residual from the calibration residual calculating unit 108. Further, the calibration residual compensated driven distance calculating unit 1 10 is programmed to determine the calibration residual compensated driven distance based on the real time capacity of the energy storage system, initial capacity of the vehicle, initial DTE value of the vehicle and the calibration residual. In an embodiment, the calibration residual compensated driven distance is calculated as

Calibration residual compensated driven distance = {Real-time capacity/Initial

Capacity}* {Initial DTE Value - sqrt(Calibration Residual)}.

[0025] In an embodiment, the distance to empty calculation unit 1 1 1 is configured to receive information on the initial DTE value from the second input module 1 12b, information on the calibration residual from the calibration residual calculating unit 108 and the information on the calibration residual compensated driven distance from the calibration residual compensated driven distance calculating unit 1 10. Further, the distance to empty calculation unit 1 1 1 is configured to calculate the DTE value compensated by the real time parameters from the initial DTE value, calibration residual and the calibration residual compensated driven distance. In an embodiment, the DTE compensated by real time parameters is calculated as

DTE = {Initial DTE Value - CRCCDD value - sqrt(Calibration Residual)} .

[0026] It should be noted that the aforementioned configuration of system 100 is provided for the ease of understanding of the embodiments of the invention. I lowever, certain embodiments may have a different configuration of the components of system 100 and certain other embodiments may exclude certain components of the system 100. Therefore, such embodiments and any modification by addition or exclusion of certain components of the system 100 without otherwise deterring the intended function of the system 100 as is apparent from this description and drawings are also within the scope of this invention. [0027] FIG. 3 is a flow chart depicting a method 200 for determining DTE value for the vehicle according to an embodiment of the present invention. The method 200 includes receiving information on at least one of real time capacity or energy, odometer reading, temperature, terrain or grade, state of charge of the energy storage system, state of health of the energy storage system, initial DTE and initial capacity of the energy storage system (step 202). At least one of real time capacity or energy, odometer reading, temperature, terrain or grade, state of charge of the energy storage system, state of health of the energy storage system, initial DTE and initial capacity of the energy storage system is determined by using any of the conventional methods. Further, the method 200 includes calculating adaptive usage efficiency parameter based on the real time capacity or energy or SoC and the distance travelled (Step 204). In an embodiment, the optimized capacity is obtained by performing controlled experiments at specific fuel efficiencies on a rolling dynamometer. Further, the adaptive usage efficiency parameter is obtained between optimized capacity efficiencies and drives that have similar capacity efficiency numbers. The driven distance based on the adaptive usage efficiency parameter is calculated using real time capacity of the energy storage system, adaptive usage efficiency parameter, initial DTE value and initial capacity of the energy storage system (step 206). In an embodiment, the driven distance based on adaptive usage efficiency parameter is calculated as,

[0028] The calibration residual is calculated based on the driven distance based on adaptive usage efficiency parameter in real time and the driven distance identified from odometer (step 208). In an embodiment, the calibration residual is calculated as {Distance Driven Calculation - Distance Driven from odometer}²

[0029] The calibration residual compensated distance driven is calculated from the real time capacity, initial DTE value, initial capacity and the determined calibration residual (step 210). In an embodiment, the calibration residual compensated distance driven is calculated as {Real-time capacity/Initial Capacity}* {Initial DTE Value - sqrt(Calibration Residual)}

[0030] The distance to empty (DTE) value is calculated from the initial DTE value, calibration residual and the calibration residual compensated distance driven (step 212). In an embodiment, the DTE value is calculated as

{Initial DTE Value - CRCCDD value - sqrt(Calibration Residual)}

[0031] It should be noted that the aforementioned steps for determining DTE value for the vehicle are provided for the ease of understanding of the embodiments of the invention. However, various steps provided in the above method may be performed in the order presented, or simultaneously. Further, in some embodiments, one or more steps listed in the above method may be omitted or modified. Therefore, such embodiments and any modification that is apparent from this description and drawings are also within the scope of this invention.

[0032] As is evident from the above description, with the system 100 and the method 200 disclosed herein, the objectives as was set forth initially will be achieved

[0033] 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.

Referal numerals:

Claims

CLAIMS We claim:

1. A system 100 for determining Distance To Empty (DTE) of a vehicle, said system comprising: an input means for receiving information on at least one of a real time capacity, an odometer reading, temperature, terrain or grade, state of charge of energy storage system, state of health of Energy Storage System, initial capacity of energy storage system and an initial DTE of the vehicle;

a control unit 102 configured for receiving information from the input means and regulate functioning of at least one of adaptive usage efficiency parameter detection unit 104, a driven distance calculating unit 106, a calibration residual calculation unit 108, a calibration residual compensated driven distance calculating unit 1 10 and a distance to empty calculation unit 1 1 1 to determine said distance to empty; and

an output means for displaying information received from the control unit 102.

2. The system as claimed in claim 1, wherein the input means includes a first input module 1 12a configured to provide information on at least one of a real time capacity of the vehicle, an odometer reading, temperature, terrain or grade, state of charge of the energy storage system of the vehicle and state of health of the energy storage system of the vehicle.

3. The system as claimed in claim 1, wherein the input means further includes a second input module 1 12b configured to provide information on an initial capacity of the energy storage system of a vehicle and an initial DTE.

4. The system as claimed in claim 2, wherein the output means includes a human machine interface or a display 1 14.

5. The system as claimed in claim 1, wherein said adaptive usage efficiency parameter calculating unit 104 is programmed to determine the adaptive usage efficiency parameter in real time based on the real time capacity or energy or state of charge (SOC) for the travelled distance and the optimized capacity or energy or state of charge for the travelled distance.

6. The system as claimed in claim 1, wherein the driven distance calculating unit 106 is programmed to calculate the driven distance based on the adaptive usage efficiency parameter using the information on real time capacity, initial capacity, initial DTE value and the adaptive usage efficiency parameter.

7. The system as claimed in claim 1, wherein the calibration residual unit 108 is programmed to calculate the calibration residual based on the driven distance based on adaptive usage efficiency parameter in real time and the odometer driven distance.

8. The system as claimed in claim 1, wherein the calibration residual compensated driven distance calculating unit 1 10 is programmed to determine the calibration residual compensated driven distance based on the real time capacity of the energy storage system, initial capacity of the energy storage system, initial DTE value and the calibration residual.

9. The system as claimed in claim 1, wherein the distance to empty calculation unit 1 1 1 is configured to calculate the DTE value compensated by the real time parameters from the initial DTE value, calibration residual and the calibration residual compensated driven distance.

10. A method 200 for determining Distance To Empty (DTE) of a vehicle, said method comprising: receiving information on at least one of a real time capacity, an odometer reading, temperature, terrain or grade, state of charge of energy storage system, state of health of Energy Storage System, initial capacity of energy storage system and an initial DTE; calculating adaptive usage efficiency parameter in real time based on at least one of real time capacity or energy or state of charge (SoC) for the travelled distance and the optimized capacity or energy or state of charge for the travelled distance;

calculating driven distance based on at least one of said adaptive usage efficiency parameter, said real time capacity, said initial capacity of energy storage system, said initial DTE value; calculating calibration residual based on at least one of said driven distance and said odometer driven distance;

calculating calibration residual compensated driven distance based on at least one of said real time capacity of the energy storage system, said initial capacity of the vehicle, said initial DTE value of the vehicle and said calibration residual; and

calculating distance to empty value based on at least one of said initial DTE value, said calibration residual and said calibration residual compensated driven distance.