FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF INVENTION


Instrument Cluster Odometer Resetting Method For Automobile Application.
APPLICANTS
TATA MOTORS LIMITED, an Indian company
having its registered office at Bombay House,
24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India
INVENTORS
Ms. Sarita Shashank Dhumal and Mr.Randeep Singh Khokar
Both are Indian Nationals
of TATA MOTORS LIMITED,
an Indian company having its registered office
at Bombay House, 24 Homi Mody Street, Hutatma Chowk,
Mumbai 400 001 Maharashtra, India

PREAMBLE TO THE DESCRIPTIONS
The following specification particularly describes the invention and the manner
in which it is to be performed.


FIELD OF INVENTION
This invention relates to method of resetting odometer reading [electronic LED/LCD display] on instrument cluster used in automobiles before handing over the vehicle to customer. This is applicable only for electronic instrument cluster.
BACKGROUND OF INVENTION
A vehicle accumulates a few kilometers in form of odometer reading on instrument cluster before actually handing over to customer. An odometer reading is an important parameter for accepting or rejecting warranty claims done by dealer / customer. An instrument cluster accumulates odometer reading in following stages before actually reaching the customer;
1. Final calibration check at instrument cluster manufacturer end
2. Vehicle checking after final assembly at vehicle manufacturer
3. Transit from vehicle manufacturer to dealership [ loading / unloading from transport vehicle ]
4. Test drive at dealer before handing over vehicle to customer.
During all these processes, usually kilometer reading accumulated on cluster is usually more that 80 km but less than 255km.
If this reading is not zeroed down at the time of sale, customer looses useful warranty period in which he can claim failure if any. In order to pass on this benefit to customer, usually odometer reading is reset to zero at the time of sale.
Different methods used for resetting odometer reading to zero are as given below;
1. Using CAN communication and sending appropriate message to cluster
2. Using trip set and reset switches in a particular sequence


A method is proposed for implementation on vehicle which uses fuel level sensor input for resetting odometer reading to zero once in lifetime of instrument cluster if the odometer reading is less than 255km.
This method does not require any high end architecture like CAN , K Line , LIN and additional devices like switches.
This method uses an analog input from fuel level sensor and for a particular condition set, resets odometer reading.
OBJECTS OF INVENTION
The main object of this invention is to achieve a simple to use and cost effective method for odometer resetting. This can be used at any dealership.
This method does not require additional switch or high tech architecture for resetting the reading.
This method uses fuel level sensor input and resets the odometer reading for a particular condition of sensor output.
STATEMENT OF INVENTION
With this method, odometer reading on electronic instrument cluster can be reset without need of diagnostic tools / k line. A simple algorithm is designed which uses existing input of fuel level sensor.
BRIEF SUMMARY OF INVENTION
Typically on any automobile instrument cluster is used for showing Vehicle speed, Accumulated Kilometer, Fuel level in tank, Engine coolant temperature, and


indicators, such as, Side turn, battery charge, park brake status, brake fluid status, EMS related signals
During normal running of vehicle, odometer value is stored in memory and display is refreshed at a defined frequency.
Normal practice to reset odometer is by using diagnostic tools / reset switches. With this invention, a method is demonstrated by which odometer reading can be reset by using fuel level sensor input cluster.
A fuel level sensor is a potentiometer type sensor in which resistance value varies in a defined range. E.g. for a particular application resistance values varies between 40 ohm to 150 ohm depending upon available fuel level.
A particular sequence of operation is sensed and then the odometer is reset to zero. Accordingly, the present invention discloses a method of one-time resetting odometer reading on instrument cluster used in automobiles comprising the steps of: providing a short circuit link at a fuel level sensor output in ignition OFF condition; checking if fuel level sensor is grounded for more than a predetermined time period in ignition ON condition; checking if current odometer reading is within a certain predetermined value; checking if odometer was reset earlier; resetting the odometer when fuel level sensor is grounded for more than said predetermined time period and if no such odometer reading was reset earlier and odometer reading is within a certain predetermined value.
In a preferred embodiment said predetermined time period is preferably 10 seconds and the predetermined current odometer value is preferably 255 Kilometers.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF INVENTION
Referring now to the drawings wherein the illustrations are for the purpose of


demonstrating a preferred embodiment of the invention only, and not for the purpose of limiting the same
Fig 1 shows the method for resetting odometer value according to this invention
Referring to Fig 1, a method is disclosed where the instrument cluster resets odometer reading once in lifetime of instrument cluster if the odometer reading is less than 255km.
Short circuit link connected at the 'Fuel sensor' output and ground shall be sensed by instrument cluster to achieve 'one time reset of season odometer' functionality. The zero ohm resistance or shorting link shall be connected temporarily at the vehicle harness tapping provided close to fuse box only if the season odometer is to be reset.
Refer table given in Fig 2,
Sequence of operations and timing is defined.
The cluster shall enter the 'one time reset of season odometer' mode only if the following conditions are satisfied:
1. The season odometer reading is less than 255 kms
2. The season odometer was not reset earlier by the 'one time reset of season
odometer mode.
3. Fuel level sensor is grounded for more than 10 sec with ignition ON.
The cluster shall display 'odo 00* for two seconds and resume normal operation if odometer value is reset successfully.
If attempt is made to reset odometer reading more than 1 time, cluster shall display 'LOCKED' for five seconds and resume normal operation.


WE CLAIM
1. A method of one-time resetting odometer reading on instrument cluster used
in automobiles comprising the steps of:
providing a short circuit link at a fuel level sensor output in ignition OFF condition;
checking if fuel level sensor is grounded for more than a predetermined time period in ignition ON condition;
checking if current odometer reading is within a certain predetermined value;
checking if odometer was reset earlier;
resetting the odometer when fuel level sensor is grounded for more than said predetermined time period and if no such odometer reading was reset earlier and odometer reading is within a certain predetermined value.
2. The method as claimed in claim 1, wherein said predetermined time period is preferably more than 10 seconds and the predetermined odometer value is preferably less than 255 Kilometers.
3. The method as claimed in claim 1, wherein said short circuit link connected at said fuel level sensor output and ground shall be sensed by said instrument cluster to achieve one-time reset of odometer functionality.
4. The method as claimed in claim 3, wherein said short circuit link is connected temporarily at a vehicle harness tapping which is provided close to a fuse box to achieve said one-time reset of odometer.
5. The method as claimed in claim 1, wherein said instrument cluster is configured to display 'odo 00" for a preset time period and then resumes normal operation.


6. The method as claimed in claim 5, wherein said preset time period for which said instrument cluster is configured to display 'odo 00' is preferably 2 seconds.
7. The method as claimed in claim 1, wherein said instrument cluster is configured to display 'LOCKED' for subsequent trial to reset the same and resumes normal operation without being reset.
8. The method as claimed in claim 7, wherein time period for which said instrument cluster is configured to display 'LOCKED' for subsequent trial to reset is preferably 5 seconds.
9. A method of one-time resetting odometer reading on instrument cluster used in automobiles hereinabove described with reference to the accompanying figures.
10. A system for one-time resetting odometer reading on instrument cluster in automobiles for performing the method as claimed in the preceding claims.
Dated this 31st day of March 2009
TATA MOTORS LIMITED By their Agent & Attorney

Karuna Goleria of DePENNING & DePENNING