Title of Invention

MAP BASED AUTOMOTIVE CONTROL SYSTEM FOR VEHICLES AND METHOD OF ACCESSING MAPS THEREIN

Abstract This invention relates to map based automotive control system for vehicles and method of accessing maps therein, and is based on a low cost 8 bit micro-controller based hardware using an efficient and fast map access algorithm. Both the hardware and software architecture of the control unit are easily amenable for introducing future functional enhancements without additional cost. Said system consists of an 8-bit micro-controller with input and output interfaces for typical automotive application. PWM power outputs drive means such as EGR solenoid; fan etc. which can be either on/off type or of proportional control type. The software implements map based strategy by using an efficient data access algorithm thus minimizing real time overheads yet occupying minimal code foot-print in the program memory .The unit meets application requirements of a low cost vehicle which cannot afford to have dedicated controllers for different vehicle functions. Fig.2
Full Text FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
Map based automotive control system for vehicles and Method of accessing maps therein
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
Mr. Vishwas Vaidya, Mr. Ameya Tipnis and Mr. Rakhesh B.
all 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 DESCRIPTION
The following specification particularly describes the invention and the matter in which it
is to be performed.

FIELD OF INVENTION
This invention relates to a control systems used in vehicles and more particularly it relates to control system used to control the out put units such as EGR (Exhaust Gas Re-circulator), fan, relays etc.
BACKGROUND OF THE INVENTION
Automotive control systems are characterized by the stringent cost versus performance demands placed on the implementation strategy. Since these control units tend to employ low cost micro-controllers, computation speed and memory resources available are modest compared to the control application complexity.
The control unit hardware and software intended for low cost high performance diesel vehicles especially for developing markets must meet following main demands:
- It should be easily upgradeable to next higher emission standards without requiring any hardware change
- It should employ fast and efficient algorithms so that CPU memory and processing power can be shared by as many additional functions as possible during future course of development.
- It should preferably have versatile architecture for incorporating other auxiliary vehicle controls like Fan control, Air-Conditioning control, glow-plug control etc.
Conventional control systems tend to use computation intensive algorithms or hardware intensive solutions which prevent usage of a low cost micro-controller apart from eating-up processor memory and computational resources. This in turn makes future feature enhancements difficult without costly hardware modifications.


Accessing map based data stored in matrix format is frequently used software operation in automotive control systems. Conventional systems use classic approach of accessing two dimensional arrays.
US 2003/0041845 describes a computationally intensive solution involving estimation of EGR rate based on multiple temperatures in the air-path which cannot be implemented on a low cost micro-controller. The estimation involves finding out differences between intake gas temperature and atmospheric temperature as well as between exhaust gas temperature and atmospheric temperature. Ratio of these two differences gives estimation of actual EGR flow. Computation of ratio of differences apart from being complex also increases cost of the total system due to requirement of three temperature sensors.
US 6,467,469 describe implementation of complex EGR control strategy in an already existing dedicated engine controller unit. Such a solution is not suitable for low cost diesel vehicles which cannot afford to have such a dedicated engine controllers and also such dedicated controllers cannot have versatile architecture for catering to auxiliary vehicle functions.
US 6,012,437 describes a hardware intensive solution (involving op-amp and transistor based control circuits) making tuning across the vehicle platforms very difficult and also it is not possible to incorporate other auxiliary vehicle functions (say Fan and air-conditioning control) in the same controller.
The drawbacks associated with above cited prior art are:
- Lack of versatile control architecture so as to cater to auxiliary vehicle functions.
- Computationally complex control strategies or hardware intensive control circuits
increasing the cost. This also makes such solutions difficult to adapt across different
vehicle platforms.


Large machine-code foot-print size and increased execution time overheads.
OBJECTS OF INVENTION
The main object of this invention is to provide a map based automotive control system for vehicles, which is able to give enhanced results for future developments.
Another object of this invention is to provide a map based automotive control system for a vehicle with provisions of qualitative and/or quantitative enhancements without requiring any hardware modifications.
Yet another object of this invention is to provide simple and cost-effective map based automotive control system catering to automotive application requirements.
STATEMENT OF INVENTION
Map based automotive control system for vehicles comprising of micro-controller, plurality of input interface means and plurality output drive means, wherein microcontroller input ports are connected to said input interface means and micro-controller out put ports are connected to output drive means, said input interface means are connected to input signal means and said output drive means are connected to output means and map based control software using map access algorithm based on one dimensional array is embedded in said micro-controller.
Map based automotive control system wherein said input interface means comprising of filters and clamping circuits for processing input signals for making them suitable to be read by micro-controller input ports.


Map based automotive control system wherein said out put drive means comprising of driver chips and Mosfet drivers for actuating the output means.
Map based automotive control system wherein said input signal means is engine/vehicle RPM, and /or alternator load and/or alternator frequency and/or temperature/pressure sensors and/or EGR position feedback and/or battery voltage and/or throttle voltage and/or crank/ignition switches and /or feedback from on/off output means.
Map based automotive control system wherein said output signal means is relays and/or cold advance solenoids and/or lamps and/or proportional EGR and/or variable geometry turbo-charger and/or fans and/or ON/OFF EGR.
Map based automotive control system wherein said microcontroller is equipped with spare inputs and spare outputs to accommodate additional number of functions for catering to future enhancements.
Map based automotive control system wherein said microcontroller is equipped with spare inputs and spare outputs to accommodate enhanced refinements for catering to advanced application requirements.
Method of accessing map/s based on one dimensional array comprises following steps:
a. Acquiring field inputs such as coolant temp., engine RPM, throttle voltage etc.
b. Computing indices required for the map, based on inputs obtained from said
step(a);
c. Packing row index and column index as obtained from step(b) in one single byte
to access the map data matrix as one dimensional array;
d. Transferring the accessed data from step (c) to output means.


BRIEF SUMMARY OF THE INVENTION
The control system in accordance with this invention comprises of a micro-controller, input interface circuits and output driver circuits. The input interface circuits are connected to automotive input signals on one end and to micro-controller input ports on the other end. Output drivers are connected to output ports of the micro-controller on one end and to the actuator/output devices used in the application on the other end.
The input interface circuits receive signals such as alternator frequency signal, coolant temperature signal etc. from external devices. Filters, clamping circuits are used in the said input interface for processing the said signals for making them suitable to be read by micro-controller input ports.
The micro-controller runs control algorithms on said inputs and generates output driving signals for driving the output devices such as actuators/lamps etc. through output driver circuits. Output driver circuits transform the raw output signals from micro-controller output ports for making them suitable for driving the actuators/lamps connected to the driver chips.
The software used in a said system comprises of a data acquisition module to read the said input signals and convert them to a form suitable for processing by the control algorithm. The control algorithm is based on a map based strategy. It decodes the input signals read by the data acquisition module to select the appropriate data element from an appropriate map. The map access algorithm is responsible for benefits related to reduction of execution time overhead as well as machine code foot-print size.
DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION
Referring now to the drawings wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only, and not for the purpose of limiting the same


Fig 1 shows the Flow Diagram of the Control System
Fig 2 Shows the Flow Diagram of the Hardware Architecture
Fig 3 Shows the Flow Diagram of Map Based Control System
Fig 4 Gives the Flow Chart for the Over all Control Software
Fig. 5 Depicts the Flow-chart for the efficient "Map Access algorithm"
Referring to Fig.l, the control system consists of low cost 8-bit micro-controller based
control unit and associated inputs/outputs. For EGR application, field inputs to the
system consist of coolant temperature, engine rpm and throttle voltage. Pulse Width
Modulated (PWM) output drives the EGR solenoid. For ON/OFF type EGR, 100% PWM
is being set for EGR 'On' and 0% for EGR 'Off. For proportional EGR, intermediate
PWM values as EGR position set points are used.
Spare inputs and spare outputs have been provided for functional enhancements to cater to future requirements such as fan control, cold advance, fast idling control etc. which are mentioned in table 1 below. Table 1: Signal Interfaces and Applications

Sr.No. Signal Description Typical Automotive Applications
1.0 Pulse/Square wave Inputs Engine/Vehicle RPM, Alternator load and Frequency
2.0 Analog/Resistive sensor Inputs Temperature/pressure sensors, EGR position feedback, Battery Voltage, Throttle Pot.
3.0 Digital inputs Crank/ignition switches, feedback from on/off outputs
4.0 Digital Outputs Relays, Cold Advance Solenoids, Lamps
5.0 PWM Outputs For proportional EGR, Variable Geometry turbo-charger
Fig 2 depicts the detailed flow-diagram of hardware architecture of the control unit. The hardware consists of an 8 bit micro-controller, input interface circuits and output driver


circuits. Input interface circuits receive various field inputs and feed the processed signals to micro-controller input ports. Driver chips have their inputs connected to microcontroller outputs. These chips have power-handling outputs which drive on/off style outputs whereas Mosfet based drivers drive PWM output devices as mentioned in the said Table 1.
Fig 3 explains the map based control strategy. Maps consist of EGR position set point data configured in the form of 16x16 matrix data structures. Three different maps are used for three different operating conditions. Each map has a prescribed rule-base associated with it.
When conditions specified in the rule base become true then the associated map becomes active. Field inputs are processed by 'Map Selection Logic' to activate appropriate Map. Index search algorithms sense engine rpm and throttle positions read from field inputs respectively and compute Row and Column Indices. Map access algorithm (not shown in this figure) read the active map data by using row and column indices.
Figure 4 show the over all flow-chart for the control logic. It follows the classic architecture consisting of input--> Process--> output. The control loop is triggered every 100 m sec. The flow chart depicts the logic sequence of all the steps required to read the input signals, processing them as per the rule base shown in fig.3 and writing the accessed value of the EGR position to the EGR output.
Fig 5 describes the 'Efficient Map Access Algorithm'. This algorithm does not read a matrix data as a two dimensional array (which requires the compiler to carry out eight bit multiplication for address computation); it treats every map as a 256 element one dimensional array. Address of the required element of the array is computed by packing row index nibble and column index nibble in one byte. This strategy saves real time penalty and machine code foot-print size drastically by 80% compared to the traditional


approach. Because of the savings in execution time and code memory space caused by the efficient map access algorithm, more functions can be packed in the controller for future enhancements thus extracting more value for money.
Method of accessing map/s based on one dimensional array comprises following steps:
a. Acquiring field inputs such as coolant temp., engine RPM, throttle voltage etc.
b. Computing indices required for the map, based on inputs obtained from said
step(a);
c. Packing row index and column index as obtained from step(b) in one single byte
to access the map data matrix as one dimensional array;
d. Transferring the accessed data from step (c) to output means.
The foregoing description is a specific embodiment of the present invention. It should be appreciated that this embodiment is described for purpose of illustration only, and that numerous alterations and modifications may be practiced by those skilled in the art without departing from the spirit and scope of the invention. It is intended that all such modifications and alterations be included insofar as they come within the scope of the invention as claimed or the equivalents thereof.


WE CLAIM
1. Map based automotive control system for vehicles comprising of microcontroller, plurality of input interface means and plurality output drive means, wherein micro-controller input ports are connected to said input interface means and micro-controller out put ports are connected to output drive means, said input interface means are connected to input signal means and said output drive means are connected to output means and map based control software using map access algorithm based on one dimensional array is embedded in said micro-controller.
2. Map based automotive control system as claimed in claim 1 wherein said input interface means comprising of filters and clamping circuits for processing input signals for making them suitable to be read by micro-controller input ports.
3. Map based automotive control system as claimed in claim 1 wherein said out put drive means comprising of driver chips and Mosfet drivers for actuating the output means.
4. Map based automotive control system as claimed in claims 1 to 3 wherein said input signal means is engine/vehicle RPM, and /or alternator load and/or alternator frequency and/or temperature/pressure sensors and/or EGR position feedback and/or battery voltage and/or throttle voltage and/or crank/ ignition switches and /or feedback from on/off output means.
5. Map based automotive control system as claimed in claims 1 to 3 wherein said output signal means is relays and/or cold advance solenoids and/or lamps and/or proportional EGR and/or variable geometry turbo-charger and/or fans and/or ON/ OFF EGR.
6. Map based automotive control system as claimed in claims 1 to 5 wherein said micro-controller is equipped with spare inputs and spare outputs to accommodate additional number of functions for catering to future enhancements.


7. Map based automotive control system as claimed in claims 1 to 6 wherein said micro-controller is equipped with spare inputs and spare outputs to accommodate enhanced refinements for catering to advanced application requirements.
8. Method of accessing map/s based on one dimensional array comprises following steps:
a. Acquiring field inputs as claimed in claim 4;
b. Computing indices required for the map, based on inputs obtained from
said step (a);
c. Packing row index and column index as obtained from step(b) in one
single byte to access the map data matrix as one dimensional array;
d. Transferring the accessed data from step (c) to output means as claimed in
claim 5.
9. Map based automotive control system for vehicles substantially as herein described with reference to accompanying drawings.
10. Method of accessing map/s based on one dimensional array substantially as herein described with reference to accompanying drawings.

ABSTRACT
Map based automotive control system for vehicles and method of accessing maps therein
This invention relates to map based automotive control system for vehicles and method of accessing maps therein, and is based on a low cost 8 bit micro-controller based hardware using an efficient and fast map access algorithm. Both the hardware and software architecture of the control unit are easily amenable for introducing future functional enhancements without additional cost. Said system consists of an 8-bit micro-controller with input and output interfaces for typical automotive application. PWM power outputs drive means such as EGR solenoid; fan etc. which can be either on/off type or of proportional control type. The software implements map based strategy by using an efficient data access algorithm thus minimizing real time overheads yet occupying minimal code foot-print in the program memory .The unit meets application requirements of a low cost vehicle which cannot afford to have dedicated controllers for different vehicle functions. Fig.2


Documents:

1605-mum-2007-abstract(granted)-(17-3-2011).pdf

1605-mum-2007-abstract.doc

1605-mum-2007-abstract.pdf

1605-mum-2007-cancelled pages(10-2-2011).pdf

1605-MUM-2007-CLAIMS(AMENDED)-(10-2-2011).pdf

1605-MUM-2007-CLAIMS(AMENDED)-(15-3-2011).pdf

1605-MUM-2007-CLAIMS(AMENDED)-(16-3-2011).pdf

1605-mum-2007-claims(granted)-(17-3-2011).pdf

1605-MUM-2007-CLAIMS(MARKED COPY)-(15-3-2011).pdf

1605-MUM-2007-CLAIMS(MARKED COPY)-(16-3-2011).pdf

1605-mum-2007-claims.doc

1605-mum-2007-claims.pdf

1605-mum-2007-correspondence(15-3-2011).pdf

1605-MUM-2007-CORRESPONDENCE(16-3-2011).pdf

1605-mum-2007-correspondence(31-8-2007).pdf

1605-mum-2007-correspondence(ipo)-(28-3-2011).pdf

1605-mum-2007-correspondence-received.pdf

1605-mum-2007-description (complete).pdf

1605-mum-2007-description(granted)-(17-3-2011).pdf

1605-MUM-2007-DRAWING(10-2-2011).pdf

1605-mum-2007-drawing(22-8-2007).pdf

1605-mum-2007-drawing(granted)-(17-3-2011).pdf

1605-mum-2007-drawings.pdf

1605-MUM-2007-FORM 18(31-8-2007).pdf

1605-mum-2007-form 2(granted)-(17-3-2011).pdf

1605-mum-2007-form 2(title page)-(22-8-2007).pdf

1605-mum-2007-form 2(title page)-(granted)-(17-3-2011).pdf

1605-MUM-2007-FORM 3(10-2-2011).pdf

1605-mum-2007-form 3(22-8-2007).pdf

1605-MUM-2007-FORM 8(31-8-2007).pdf

1605-mum-2007-form 9(31-8-2007).pdf

1605-mum-2007-form-1.pdf

1605-mum-2007-form-2.doc

1605-mum-2007-form-2.pdf

1605-mum-2007-form-26.pdf

1605-mum-2007-form-3.pdf

1605-MUM-2007-GENERAL POWER OF ATTORNEY(10-2-2011).pdf

1605-MUM-2007-MARKED COPY(10-2-2011).pdf

1605-MUM-2007-REPLY TO EXAMINATION REPORT(10-2-2011).pdf

1605-MUM-2007-REPLY TO HEARING(15-3-2011).pdf

1605-MUM-2007-SPECIFICATION(AMENDED)-(10-2-2011).pdf

abstract1.jpg


Patent Number 246856
Indian Patent Application Number 1605/MUM/2007
PG Journal Number 12/2011
Publication Date 25-Mar-2011
Grant Date 17-Mar-2011
Date of Filing 22-Aug-2007
Name of Patentee TATA MOTORS LIMITED
Applicant Address BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI
Inventors:
# Inventor's Name Inventor's Address
1 VISHWAS VAIDYA BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI-400001
2 AMEYA TIPNIS BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI-400001
3 RAKHESH B BOMBAY HOUSE, 24 HOMI MODY STREET, HUTATMA CHOWK, MUMBAI-400001.
PCT International Classification Number G01C21/20,B60K35/00
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 NA