FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION (See Section 10; rule 13)
TITLE OF THE INVENTION
“A METHOD FOR VEHICLE IMMOBILIZATION AND SYSTEM
THEREOF”
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
PREAMBLE TO THE DESCRIPTION:
The following Complete specification particularly describes the invention and the manner in which it is to be performed.

TECHNICAL FIELD
This invention is related to the field of automobile vehicle equipped with transponder based immobilizer system. More particularly this invention is to provide uninterrupted immobilization feature/service to vehicle owner in the event of primary immobilizer hardware i.e. the transponder base immobilizer failure or malfunction.
BACKGROUND OF THE INVENTION:
Making modern day vehicles employs numerous techniques for improving vehicle security such as immobilization, biometric access and others. Vehicle immobilization is one of the earliest security systems. RKE based immobilization systems and transponder key based immobilization systems forms two major types of immobilization in today’s vehicles. Most of the vehicles built today are built with either RKE based or Transponder key based immobilization. However, there is no alternative system provide when these system fail to function.
STATEMENT OF INVENTION
Accordingly, the present disclosure relates to a method for vehicle immobilization comprising acts of: sending a predefined pulsating signal by an immobilizer unit to a body control module (BCM) when the vehicle ignition is ON after the BCM is paired with valid remote key; checking status signal of immobilizer unit when the pulsating signal received by the BCM does not match with predefined signal characteristics; determining engine RPM by BCM when the status signal is continuous low and comparing the determined RPM with predefined RPM value for performing, turning ON fuel cut off relay when RPM is greater then a predetermined value, else, turning ON fuel cut off relay and starter relay whenever crank signal is present; and also relates to a system for vehicle immobilization comprising: an immobilizer unit to send a predefined pulsating signal to a body control module (BCM) when the vehicle ignition is ON after the BCM is paired with remote key entry, wherein the BCM checks status signal of immobilizer unit when the pulsating signal received by the BCM does not match with predefined signal characteristics; said BCM compares present engine RPM with predefined RPM value and when the status signal is low for greater than predefined time and performs, turning ON fuel cut off relay when RPM is

greater then a predetermined value; else, turning ON fuel cut off relay and starter relay when crank signal is present.
SUMMARY
In one embodiment of the disclosure a method for vehicle immobilization comprising acts of: sending a predefined pulsating signal by an immobilizer unit to a body control module (BCM) when the vehicle ignition is ON after the BCM is paired with valid remote key; checking status signal of immobilizer unit when the pulsating signal received by the BCM does not match with predefined signal characteristics; determining engine RPM by BCM when the status signal is continuous low and comparing the determined RPM with predefined RPM value for performing,
turning ON fuel cut off relay when RPM is greater then a predetermined value, else,
turning ON fuel cut off relay and starter relay whenever crank signal is present. In one embodiment the starter relay is maintained in ON state by BCM till the time crank signal is present or for predetermined time whichever time is less.
In one embodiment the fuel cut off relay and the starter relay are controlled by the immobilizer unit when the status signal is high.
In one embodiment the starter relay are not turned ON when the vehicle RPM is zero with no crank signal.
In one embodiment the BCM does not check status signal when the vehicle ignition is in OFF condition.
In one embodiment the status signal is low for greater than 100ms.
In one embodiment the predefined value is 600 RPM or Idle RPM.
In one embodiment a system for vehicle immobilization comprising: an immobilizer unit to send a predefined pulsating signal to a body control module (BCM) when the vehicle ignition is ON after the BCM is paired with remote key entry, wherein the BCM checks status signal of immobilizer unit when the pulsating signal received by the BCM does not match with predefined signal characteristics; said BCM compares

present engine RPM with predefined RPM value and when the status signal is low for greater than predefined time and performs,
turning ON fuel cut off relay when RPM is greater then a predetermined value; else,
turning ON fuel cut off relay and starter relay when crank signal is present.
In one embodiment the starter relay is maintained in ON state till the time crank signal is present or for predetermined time whichever time is less.
In one embodiment the status signal low indicates at least one of, failure in the immobilizer unit hardware, the immobilizer unit microcontroller software runway, relay out wires form immobilizer open and short circuited and the status signal pin shorted to ground.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The novel features and characteristic of the disclosure are set forth in the appended claims. The disclosure 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 figures. One or more embodiments are now described, by way of example only, with reference to the accompanying figures wherein like reference numerals represent like elements and in which:
Figure 1 shows an immobilizer block diagram depicting output loads controlled by
both BCM and transponder based immobilizer.
Figure 2 shows state diagram during immobilizer healthy and unhealthy status signal
conditions.
Figure 3 shows Input and status signal circuit schematic hardware interfacing between
immobilizer, BCM and their common controlled loads.
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.
DETAIL DESCRIPTION
In the following detailed description, reference is made to the accompanying figures, which form a part hereof. In the figures, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, and figures are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, and designed in a wide variety of different configurations, all of which are explicitly contemplated and make part of this disclosure.
In most of the countries, any car sold is required to have built in immobilization function. The different number of immobilization techniques available in contemporary cars range from Remote Keyless Entry (RKE) based immobilization to transponder based immobilization. The remote key in typical automobile consists of transponder and transmitter circuitry which is paired with immobilizer and BCM respectively.
Figure 1 shows an illustrative embodiment of the instant disclosure with two way immobilization block diagram. The block diagram shows the transponder based immobilizer as primary immobilizer while as RKE based BCM acts as a secondary immobilizer. A Transponder based immobilizer consists of 2 parts, Remote key with transponder chip and immobilizer unit along with mechanical ignition barrel. The immobilizer unit sitting in the vehicle is normally full-fledged microcontroller based unit for receiving various input signals from transponder and other sensors, depending upon the authentication of the signal; the immobilizer typically enables fuel cut off relay and starter motor relay. In some vehicle architectures, the immobilizer also sends authentication signal to Engine Management System (EMS) ECU.

Figure 1 shows various connection between Transponder Based Immobilizer (TBI) unit 101, BCM 102, Starter relay 103, immobilizer signal connection to engine ECU 104, fuel cut off solenoid/relay 105 and remote key 106. The description of various signals connecting these blocks and there description is given in table 1.
Table 1: Signal description for Figure 1.

Signal Description
1 Starter relay output controlled by transponder immobilizer ECU
2 Key authentication signal to EMS ECU from transponder immobilizer ECU
3 Fuel cut off solenoid output signal form transponder immobilizer ECU
4 Starter relay output controlled by BCM.
5 Key authentication signal to EMS ECU form BCM
6 Fuel cut off solenoid output signal form BCM
7 Immobilizer fail-safe signal to BCM ( this is same signal as status signal at pin X1.1)
8 Key-inserted signal
9 Ignition signal
10 Crank signal
11 RKE lock/un-lock signal
The BCM 102 is also made capable of controlling starter relay 103 and fuel cut off relay 105 apart from TBI unit 101. Further, the BCM 102 is fed with RKE lock/unlock signal 11 from a remote key 106. As soon as the ignition is ON, the BCM 102 checks for RKE lock/un-lock signal. If the remote key 106 is paired by providing a valid key, the BCM 102 then starts receives the transponder based immobilizer 101 fail-safe signal 7. The fail-safe signal 7 is generated by immobilizer microcontroller in predefined pulsating format and received by BCM 102. The received signal is compared with predefined signal characteristics for predefined duration like a scanning window. In the event of correct signal reception, fuel cut off relay/solenoid 105 and starter motor relay 103 are controlled by TBI unit 101. When BCM 102 does not receive correct status pulse from immobilizer for predefined duration, it checks status signal for active high signal at status input pin X1.1 of Immobilizer Status signal Input detection circuitry, if status signal is active high continuously then also

the control of two output loads i.e. the starter relay 103 and fuel cut off relay 105 remains with TBI unit 101. The reason behind retaining the control with immobilizer is due to the fact that active high signal can also be asserted due to X1.1 pin open condition for which BCM 102 does not provide any limp home action.
If the status signal is present at X1.1 pin is other than correct status signal (or active high signal) BCM 102 takes over immobilizer functionality by means of controlling the further operation of fuel cut-off relay 105 and starter motor relay 103. The incorrect status signal at X1.1 pin is attributed to
• Failure of immobilizer hardware.
• Immobilizer microcontroller software runway.
• Relay output wires from immobilizer open or short circuited.
• Status Pin X1.1 shorted to ground.
If BCM 102 starts receiving incorrect status signal during vehicle operation engine RPM >600 RPM then BCM 102 will turn on fuel cut off relay 105 immediately. In vehicle stand still or Engine RPM<600 condition, BCM 102 will wait for crank signal 10, once the crank signal 10 is received, it will turn ON fuel cut off relay 103 continuously and starter motor relay 103 till crank signal 10 is present or say a predefined amount of time for example 10 sec, whichever is less.
If vehicle is in stand still condition and no crank signal 10 is present, BCM 102 will not turn on any outputs. BCM will stop monitoring the status signal during ignition OFF condition since immobilizer unit will not send any signal during ignition OFF. In the event of momentary interruption of immobilizer status signal to BCM (less than 100ms), the immobilization control will not be transferred to BCM. If the incorrect status signal is restored to correct signal anytime during vehicle running or stand still condition, the immobilization control is immediately transferred to transponder immobilizer unit.
Figure 2 shows a state diagram of providing two-way immobilization when one immobilizer fails to function properly. When the ignition is turned ON, the BCM checks if the RKE is paired with BCM using a valid key at 201. In 202 the BCM

receives predefined pulsating signal indicating heath of the primary immobilizer i.e. the transponder based immobilizer unit. This signal is then compared with predefined signal characteristic by BCM at 205. If there is a match during the comparison then the primary immobilizer will take control of the fuel cut off relay and starter relay. If there is a mismatch when comparing at 203 i.e. when BCM does not receive correct pulsating signal from the immobilizer unit for predefined duration, it checks status signal for active high signal at status input pin X1.1 of Immobilizer Status signal Input detection circuitry, if status signal is active high continuously then also the control of two output loads i.e. the starter relay and fuel cut off relay remains with TBI unit.
However, if the status signal present at X1.1 pin is other than correct status signal (or active high signal) BCM takes over immobilizer functionality at 206 by means of controlling the further operation of fuel cut-off relay and starter motor relay. At 207 the BCM checks during vehicle operation if engine RPM >600 RPM or idle RPM , wherein Idle RPM is referred as minimum RPM needed for engine to keep alternator, water pump and other accessories in running conditions, alternatively it is engine speed when the vehicle is not moving which is engine's slowest practical speed. The Idle RPM is referred here arbitrarily, for turning ON certain outputs at minimum practical engine RPM. If the RPM is greater than 600RPM, then BCM 102 will turn on fuel cut off relay immediately at 208. When the vehicle is stand still or Engine RPM<600 condition, BCM will wait for crank signal at 209. Once the crank signal is received, it will turn ON fuel cut off relay continuously and starter motor relay till crank signal 10 is present or say a predefined amount of time for example 10 sec, whichever is less. If there is no crank signal at 209, the system will check for Ignition ON status at 211 again. If Ignition ON is detected, the activity sequence in the flowchart will be repeated from 203 or else if Ignition OFF is detected at 211, the activity sequence will be aborted.
Also, it obvious to a person to indicate the status signal either as low or high to indicate the good health of the immobilizer. Any other state of the status signal would indicate failure or abnormal functioning. A particular state indicated in the description is only an exemplary embodiment; however a person skilled in the art can envisage other ways of depicting the signal to represent a particular state of the immobilizer.

Same holds good for fail-safe signal. This state diagram does not show BCM strategy during immobilizer status input wire open condition.
Figure 3 and 4 shows the circuit diagram of the output controls (input controls for relay) are managed by OR-ING the two control lines.
Equivalents
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 inventions 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 typically 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 typically be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, typically 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."
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.

We claim:
1. A method for vehicle immobilization comprising acts of:
sending a predefined pulsating signal by an immobilizer unit to a body control module (BCM) when the vehicle ignition is ON after the BCM is paired with remote key entry;
checking status signal of immobilizer unit when the pulsating signal received by the BCM does not match with predefined signal characteristics;
determining engine RPM by BCM when the status signal is continuous low and comparing the determined RPM with predefined RPM value for performing, turning ON fuel cut off relay when RPM is greater then a
predetermined value, else,
turning ON fuel cut off relay and starter relay whenever crank signal is
present.
2. The method as claimed in claim 1, wherein the starter relay is maintained in ON state by BCM till the time crank signal is present or for predetermined time whichever time is less.
3. The method as claimed in claim 1, wherein controlling the fuel cut off relay and the starter relay by the immobilizer unit when the status signal is high.
4. The method as claimed in claim 1, wherein the starter relay are not turned ON when the vehicle RPM is zero with no crank signal.
5. The method as claimed in claim 1, wherein the BCM does not check status signal when the vehicle ignition is in OFF condition.
6. The method as claimed in claim 1, wherein the status signal is low for greater than 100ms.
7. The method as claimed in claim 1, wherein the predefined value is 600 RPM or Idle RPM.
8. A system for vehicle immobilization comprising:
an immobilizer unit to send a predefined pulsating signal to a body control module (BCM) when the vehicle ignition is ON after the BCM is paired with remote key entry, wherein the BCM checks status signal of immobilizer unit when the pulsating signal received by the BCM does not match with predefined signal characteristics; said BCM compares present engine RPM with predefined RPM

value and when the status signal is low for greater than predefined time and performs,
turning ON fuel cut off relay when RPM is greater then a predetermined value; else,
turning ON fuel cut off relay and starter relay when crank signal is present.
9. The system as claimed in claim 8, wherein the starter relay is maintained in ON state till the time crank signal is present or for predetermined time whichever time is less.
10. The system as claimed in claim 8, wherein the status signal low indicates at least one of, failure in the immobilizer unit hardware, the immobilizer unit microcontroller software runway, relay out wires form immobilizer open and short circuited and the status signal pin shorted to ground.
11. A method and system for vehicle immobilization are substantially as herein above described and as illustrated in accompanying drawings.