FORM 2
THE PATENT ACT 1970
[39 OF 1970]
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
[See Section 10 and Rule 13]
TITLE: “AN ENGINE CONTROL UNIT (ECU) OF A VEHICLE”
Name and address of the Applicant:
TATA MOTORS LIMITED, Bombay house, 24 Homi Mody Street, Hutatma
Chowk, Mumbai 400 001, Maharashtra, INDIA.
Nationality: Indian
The following specification particularly describes the invention and the manner in which
it is to be performed.
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TECHNICAL FIELD
Embodiments of the present disclosure relate to an engine control unit (ECU) of a motor
vehicle. More particularly, the disclosure relates to a method for protecting the ECU from
transient voltage condition and to avoid losing data getting to be logged during the
transient voltage condition.
BACKGROUND OF DISCLOSURE
The motor vehicles have an ECU to control engine related functions. The ECU contains
the hardware and software. The hardware consists of electronic components on a printed
circuit board (PCB). The main component of the ECU is a microcontroller i.e. central
processing unit (CPU) in which the software is stored. In common practice, the
parameters related to a specific vehicle function is stored in CPU’s memory. CPU usually
has a volatile memory that is backed by a power source such as a battery and a nonvolatile
memory that protects its contents even after the power has been disconnected.
One example of a volatile memory is random access memory (RAM). One example of a
non-volatile memory is electrically erasable programmable read-only memory
(EEPROM).
The vehicle parameters are commonly stored in RAM. The vehicle parameters are the
parameters provided with an initial value that is subsequently updated and adjusted
according to a particular vehicle operating condition. When that particular vehicle
operating condition is encountered another time, the previously recorded value is utilized.
However a problem may occur when the battery of the vehicle is disconnected or if the
battery's power has been drained because of which the previously recorded value stored
in RAM is lost.
Therefore there is a need to transfer the previously recorded values from volatile memory
to non-volatile memory when the battery of the vehicle is disconnected or if the battery's
power has been drained in the vehicle. To perform this method, the automotive electronic
control applications demand robust input power-conditioning. The applications needs to
absorb 100 volt transients on one hand and provide a stable DC bus for a few hundred
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milliseconds after ignition is switched-off so that CPU can get time to transfer previously
recorded values before going off. The conventional systems meet this requirement by
using high energy transient absorbers and by using an electro-mechanical relay.
The present disclosure provides a cost-effective method for transferring the previously
recorded values of the vehicle parameters from the volatile memory to the non-volatile
memory, by replacing costly and bulky transient absorbers by an electronic switch and
also using a simple RC delay circuit, to sustain power for a preset amount of time after
the ignition is switched off.
Further, the present disclosure also provides a method for protecting the ECU from
transient voltage condition.
OBJECTS OF THE DISCLOSURE
One object of the present disclosure is to protect ECU from transient voltage condition.
One object of the present disclosure is to transfer one or more vehicle parameters from
volatile memory to non-volatile memory during ignition off condition.
One object of the present disclosure is to avoid losing the data getting to be logged during
transient voltage condition.
One object of the present disclosure is to eliminate the use of transient absorbers.
STATEMENT OF THE DISCLOSURE
Accordingly, the present disclosure provides an engine control unit (ECU) of a vehicle
comprising: a battery for providing power to the ECU; a transient detection circuit
configured to break the power to the ECU by switching a transistor switch when transient
voltage is detected; a CPU configured to detect the transient voltage, wherein the CPU
switches to sleep mode upon detection of the transient voltage; a power back-up circuit
configured to provide power to the CPU during the sleep mode; and also provides a
method comprising: detecting transient voltage by a transient detection circuit; breaking
power to ECU by switching a transistor switch upon detection of the transient voltage;
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switching CPU to sleep mode upon detection of the transient voltage; providing power to
the CPU during the sleep mode using a power back-up circuit.
SUMMARY OF THE DISCLOSURE
The shortcomings of the prior art are overcome and additional advantages are provided
through the provision of system and method as claimed in the present disclosure.
In one embodiment, the present disclosure provides an ECU of a vehicle. The ECU
comprises a battery, a transient detection circuit, a CPU and a power back-up circuit.
When an ignition switch is ON the power is provided to the ECU from the battery. When
a transient voltage is detected the transient detection circuit breaks the power to the ECU
by switching a transistor switch. Also upon detecting the transient voltage the CPU
switches to sleep mode upon. The power back-up circuit provides power to the CPU
during the sleep mode. During ignition OFF condition a delay circuit in the ECU
provides power to the CPU for a predetermined time and in this predetermined time the
CPU transfers one or more vehicle parameters from volatile memory to non-volatile
memory.
In one embodiment, the present disclosure provides a method comprising detecting
transient voltage by a transient detection circuit. Upon detecting the transient voltage, the
power is switched off to the ECU by switching a transistor switch and the CPU is
switched to sleep mode. The power is provided to the CPU during sleep mode through a
power back-up circuit.
In one embodiment, the present disclosure provides a delay circuit configured in the ECU
to provide power to the CPU for a predetermined time during ignition OFF condition by
switching the transistor switch.
In one embodiment, the CPU transfers one or more vehicle parameters from volatile
memory to non-volatile memory in the predetermined time.
In one embodiment, the one or more vehicle parameters are selected from atleast one of
air-fuel ratio, ignition timing, and idle speed.
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In one embodiment, the transient voltage is when the power from the battery exceeds a
predefined voltage.
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.
BRIEF DESCRIPTION OF THE 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:
FIG.1 shows Engine Control Unit (ECU) configuration in accordance with one
embodiment of the present disclosure.
FIG.2 illustrates a transient protection circuit in accordance with the present disclosure.
FIG.3 shows a circuit for keeping CPU in sleep mode during transient voltage condition
in accordance with the present disclosure.
FIG.4 shows a flowchart illustrating process of detection of transient voltage condition.
FIG.5 shows delay circuit configuration in accordance with the present disclosure.
FIG.6 shows a flowchart illustrating method of transferring one or more vehicle
parameters from volatile memory to non-volatile memory of CPU during ignition OFF
condition.
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.
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DETAILED DESCRIPTION
The foregoing has broadly outlined 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.
Referral Numerals
Reference Number Description
Engine Control Unit (ECU) 100
Battery 101
Transient detection circuit 103
Transistor switch 105
Ignition switch 107
Delay circuit 109
CPU 111
Power back-up circuit 113
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To overcome the drawbacks mentioned in the background, the present disclosure
provides a method to hold power for a predetermined time in an engine control unit
(ECU) during ignition OFF condition so that one or more vehicle parameters are
transferred from volatile memory to non-volatile memory of CPU in the predetermined
time. The ECU operation is controlled on the basis of recorded vehicle parameters hence
it is required to maintain the vehicle parameters for confirming proper working of system.
In another embodiment of the present disclosure, during transient voltage condition the
CPU enters into sleep. The power back-up circuit provides power to the CPU during
sleep mode.
FIG.1 shows a part of Engine Control Unit (ECU) 100 configuration in accordance with
the present disclosure. The ECU 100 consists of a battery 101, a transient detection
circuit 103, a transistor switch 105, an ignition switch 107, a delay circuit 109, a CPU
111 and a power back-up circuit 113. The battery 101 is configured in the vehicle to
provide power to the ECU. When the ignition switch 107 is ON the power is provided to
the CPU 111 and the CPU 111 stores one or more vehicle parameters in its volatile
memory. The volatile memory for example includes, but not limiting to random access
memory (RAM), dynamic random-access memory (DRAM) and static random-access
memory (SRAM). A person skilled in the art would understand that any type of volatile
memory can be used to store the one or more vehicle parameters. During ignition OFF
condition, there is no power to the CPU 111 and hence the one or more vehicle
parameters stored in the volatile memory of the CPU 111 is lost. To avoid this, the delay
circuit 109 is used. The delay circuit 109 provides power to the CPU 111 for a
predetermined time and in this predetermined time the CPU 111 transfers the one or more
vehicle parameters from the volatile memory to the non-volatile memory. The nonvolatile
memory for an example includes, but not limiting to read only memory (ROM),
erasable programmable read only memory (EPROM) and electrically erasable
programmable read-only memory (EEPROM). A person skilled in the art would
understand that any type of non-volatile memory can be used for storing the one or more
vehicle parameters.
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The vehicle parameters for example includes but not limiting to air-fuel ratio, ignition
timing, and idle speed. A person skilled in the art would understand that any type of
vehicle parameters can be stored in the CPU.
The transient detection circuit 103 is provided to protect the CPU from transient voltage.
The transient voltage is when the voltage from the battery exceeds a predefined voltage.
When the transient occurs the transient detection circuit switches OFF the transistor
switch 105. In an embodiment, the transistor switch 105 is a MOSFET. Thus, the
transistor switch 105 isolates the supply from the battery 101 to CPU. The CPU 111 also
detects the transient voltage and it switches to sleep mode. The power back-up circuit 113
provides power to the CPU 111 during the sleep mode.
FIG. 2 is a transient protection circuit in accordance with the present disclosure. During
transient voltage condition i.e. when the voltage from the battery exceeds 33 volt, the
transistor 11 turns ON and it switches OFF the MOSFET 15 thus protecting the loadcircuit
from high voltages.
FIG.3 shows a circuit for keeping CPU 111 in sleep mode during transient voltage
condition in accordance with the present disclosure. During the transient voltage
condition, the resistors 31 and 33 and diode 32 facilitate the CPU 111 to detect transient
voltage and thus the CPU 111 goes to sleep mode when transient voltage is detected. The
power back-up circuit 113 consists of capacitors 21 and 22 provides power to the CPU
111 during the sleep mode.
FIG.4 is a flowchart illustrating process of detection of over-voltage condition by the
CPU 111. At step 401, when time t=0, the voltage from the battery is normal, the CPU
111 transfers the data i.e. one or more vehicle parameters from volatile memory to nonvolatile
memory at step 403. At step 405, when time t=1, let us assume that a transient
has occurred. At step 407, the transient detection circuit 103 checks if the voltage is
greater than a predefined voltage, say for example 33 volts. If the voltage is greater than
33 volts, then at step 409, the transistor switch 105 is turned OFF and thus protects the
CPU 100 from high voltage. If the voltage is not greater than 33 volts then the CPU 111
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continues to transfer one or more vehicle parameters from the volatile memory to the
non-volatile memory. At step 411, the CPU 111 stops transferring the one or more
vehicle parameters and switches to sleep mode upon detection of the transient voltage. At
step 413, the power back-up circuit 113 maintains the charge to the CPU 111 till the CPU
111 is in sleep mode or till the transient voltage comes down from 33 volts. At step 415
the transient detection circuit 103 checks if the voltage is less than 33 volts. If the voltage
is less than 33 volts then the transient detection circuit switches ON the transient switch
and provides power to the CPU at step 417. If the voltage is not less than 33 volts then
the CPU continues to be in sleep mode till the voltage becomes less than a predetermined
voltage say for example 12 volts. At step 419, the CPU checks if the voltage is equal to
12 volts and if the voltage is equal to 12 volt then the CPU 111 wakes up from sleep
mode to normal mode and starts with transferring the one or more vehicle parameters. If
the voltage is greater than12 volts then the CPU waits till the required voltage to perform
its normal operation.
FIG.5 shows delay circuit configuration in accordance with the present disclosure. The
delay circuit 109 consists of two resistors 6 and 8, a capacitor 7, a transistor 9 and a diode
5. When the ignition switch 107 is ON, the transistor 9 stays ON and maintains the
transistor switch ON, due to which the power is provided to the CPU 111 and the CPU
111 performance its normal operation like storing one or more vehicle parameters in its
volatile memory. Also, during ignition ON condition the capacitor 7 gets charged up.
When the ignition switch 107 is OFF the CPU 111 is provided with power for a
predetermined time from the battery. The capacitor 7 which is charged during the ignition
ON condition discharges its power and this power is sufficient to hold the transistor 9 ON
for certain duration. The transistor 9 holds the transistor switch 105 ON and since the
transistor switch 105 is directly connected to the battery, the circuit remains powered as
long as the transistor 9 is ON. In this way, the delay circuit 109 helps in providing power
to the CPU 100 for a predetermined time. Further, when the CPU detects that the ignition
is OFF it starts performing its last operation which are crucial like transferring one or
more vehicle parameters from the volatile memory to the non-volatile memory. The
power supply to perform this operation when the ignition is OFF is provided to the CPU
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by the delay circuit which turns OFF the transistor switch after a delay. In an
embodiment, the predetermined time is decided by the capacitor 7 and the resistor 8 value
connected across the delay circuit.
FIG.6 shows a flowchart illustrating method of transferring one or more vehicle
parameters from volatile memory to non-volatile memory of CPU 111 during ignition
OFF condition. At step 601, the ignition switch 107 is ON and the power is provided to
the CPU 111. The CPU 111 performs is normal operation during the ON condition like
for example reading vehicle parameters from non-volatile memory etc. at step 603. At
step 605, the ECU 100 checks if the ignition switch 107 is OFF. If the ignition switch 107
is OFF the power is not supplied to the CPU and the one or more vehicle parameters
stored in the volatile memory of the CPU is lost. To avoid this loss, at step 607, power is
provided to the CPU 111 for a predetermined time using the delay circuit 109 and at step
609 the CPU 111 transfers the one or more vehicle parameters from the volatile memory
to the non-volatile memory of the CPU. At step 605, if the CPU detects that the ignition
switch 107 is ON then the CPU continues to store the one or more vehicle parameters in
its volatile memory.
Advantages:
The present disclosure eliminates the use of costly and bulky transient absorbers and uses
a simple delay circuit to eliminate the electromechanical relay.
The present disclosure protects the load circuit from high voltages by switching off the
transistor switch.
The number of pins used by the CPU to perform these operations is less as compare to
the prior art.
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
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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
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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.
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We claim:
1. An engine control unit (ECU) of a vehicle comprising:
a battery for providing power to the ECU;
a transient detection circuit configured to break the power to the ECU by
switching a transistor switch when transient voltage is detected;
a CPU configured to detect the transient voltage, wherein the CPU
switches to sleep mode upon detection of the transient voltage; and
a power back-up circuit configured to provide power to the CPU during
the sleep mode.
2. The ECU as claimed in claim 1, wherein a delay circuit is configured to provide
the power to the CPU for a predetermined time during ignition OFF condition by
switching the transistor switch.
3. The ECU as claimed in claim 2, wherein the CPU transfers one or more vehicle
parameters from volatile memory to non-volatile memory in the predetermined
time.
4. The ECU as claimed in claim 3, wherein the one or more vehicle parameters are
selected from atleast one of air-fuel ratio, ignition timing, and idle speed.
5. The ECU as claimed in claim 1, wherein the transient voltage is when the power
from the battery exceeds a predefined voltage.
6. A method comprising:
detecting transient voltage by a transient detection circuit;
breaking power to ECU by switching a transistor switch upon detection of
the transient voltage;
switching CPU to sleep mode upon detection of the transient voltage; and
providing power to the CPU during the sleep mode using a power back-up
circuit.
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7. The method as claimed in claim 6, wherein providing power to the CPU for a
predetermined time using a delay circuit by switching the transistor switch during
ignition OFF condition.
8. The method as claimed in claim 7, wherein transferring one or more vehicle
parameters stored in volatile memory to non-volatile memory of the CPU in the
predetermined time by the CPU.
9. The method as claimed in claim 7, wherein the predetermined time is decided by
capacitor and resistor value in the delay circuit.