FORM 2
THE PATENTS ACT 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
(See Section 10; rule 13)
TITLE OF THE INVENTION
On The FLY Fuel Efficiency Control
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
r
INVENTOR
Gosavi Santosh s, yelwande Yogesh, Chaskar Mithun Ravindra
All Indian national
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 describes the invention

Technical filed: The present invention is directed to an engine management system for an internal combustion engine. In particular, this invention is directed to a system and a method that compensates for a change in engine operating state by altering an amount of an operating parameter, such as quantity of fuel to be delivered.
Background of invention: In present times of high fuel costs and global warming, it is necessary for the automotive manufacturer to develop highly fuel efficient vehicles at the same time meeting all emission norms. This can be achieved by using state-of-the-art technologies like traction control, cruise control and optimized engine performance management systems. Since these modifications and features are expensive, they are not so popular for small and medium segment vehicles.
It is believed that the performance of an internal combustion engine is dependent on a number of factors including the operating cycle (e.g. two-stroke having 360 degrees of crankshaft rotation per cycle, four stroke having 720 degrees of crankshaft rotation per cycle, or Wankel), the fuel type (e.g. gasoline or diesel) the number and design of combustion chambers, the selection and control of ignition and fuel delivery systems, and the ambient conditions in which the engine operates.
With regard to fuel delivery systems, carburetors and fuel injection systems are known. It is believed that those known systems supply a quantity of fuel, e.g., gasoline and air, in accordance with the position of the throttle as set by the operator. In case of carburetors, it is believed that fuel is delivered by a system of orifices, known as "jets". As examples of carburetor operation, it is believed that an idle jet may supply fuel downstream of a throttle valve at engine idling speeds, and that fuel delivery may be boosted by an accelerator pump to facilitate rapid increases in engine load. It is believed that most carburetors must be disassembled and different size jets or pumps installed to modify the amount of fuel delivery at a particular engine load. However, that is a laborious process that, it is believed, most often, can only be done while the engine is not running.
It is also believed that known fuel injection systems, which can be operated electronically, spray a precisely metered amount of fuel into the intake system or directly into the combustion cylinder. The fuel quantity is determined by the controller based on the state of the engine and a data table known as 'map' or 'look-up table'.

The map includes a collection of possible values or 'setpoints' for each of at least one independent variable (i.e. characteristic state of the engine), which can be measured by a sensor connected to the controller and a collection of corresponding control values, for a dependent variable control function, e.g. fuel quantity.
For example, US 7,4197,201 describes a control system and methods for continuously adapting engine control parameters to optimize and adjust engine fuel consumption based upon all detectable vehicle and engine operating conditions. Therefore, the patent provides for large number of fuel maps, tailored for each conceivable condition and can be utilized to optimize engine fuel consumption based upon rapidly changing conditions. The patent document also teaches duel control system comprising plurality of sensors coupled with electronic control module. Therefore, based on road conditions, acceleration, or any other condition, the ECM detects the change in vehicle and engine operating conditions and modifies the fuelling parameters to optimize the performance for the next instance.
However, the prior art suffers from a major drawback that it is ECM with the help of sensors which detects and decides the map to be followed. In several instances, unavailability of vehicle grade, road condition and actual torque demand results in higher fuel consumption by the engine than required. For instance, at lower speeds with high gear selection, driver accelerates to increase vehicle speed while reducing fuel economy. Another instance of poor fuel economy is in case of good road conditions the driver accelerates to achieve maximum speed and consequently burns more fuel.
Another disadvantage of prior art technology is that the ECM along with its fuel maps are stored external to the engine requiring use of plurality of sensors which only increases complexity and costs to the manufacturer as well the consumer. Furthermore, storing maps externally may not be advantageous since the external device may get damaged due to atmosphere and usage.
Therefore, it is believed that a simple, effective engine management system and
. method for optimizing fuel delivery during engine operating state transitions is needed.
It is also desirable to adjust ignition timing, commonly measured in degrees of crank

rotation before a piston reaches top-dead-center of the compression stroke, to achieve specific engine performance (e.g. lowest fuel consumption or reduced emissions). It is further a desirable need that fixed speed: torque profile for maximum fuel efficiency be included in the electronic control unit such that user is not allowed to alter fixed parameters which may actually decrease the efficiency. It also believed that there is a need to provide for a vehicle including an internal combustion engine comprising an engine management system which provides high fuel efficiency while reducing undesired emissions and most importantly does not compromise on safety of the vehicle as well as the occupants.
It is the object of the present invention to provide for a technical advancement over prior art to fulfill all the aforementioned needs.
Summary of invention: The present invention relates to an engine management system and a method for adjusting the quantity of fuel delivered to an engine when an engine is in operating state transitions.
Brief description of the drawings: A full understanding of the invention can be
gained from the following description of the preferred embodiments when read in
conjunction with the accompanying drawings in which:
FIG I is a block diagram for an exemplary embodiment of engine management system
of the present invention.
FIG II shows the schematic diagram for an exemplary embodiment of electronic
control unit.
FIG III shows the flow chart adjustment of engine parameters following selection of
driving mode.
FIG IVa and IVb depict exemplary calibration curves for SUV and a Sedan class of
vehicles.
FIG V is a block diagram for an exemplary embodiment of engine management system
for an automatic transmission vehicle.

Detailed Description of the preferred embodiment: Engine management system for an internal combustion engine comprises of various sensing means for measuring plurality of engine and vehicle operating conditions in real time i.e. when the vehicle is in the transition state. The sensing means essentially include sensors for measuring vehicle speed by using flywheel speed sensor and gearbox output shaft speed sensor or such other suitable sensing device commonly used for the same purpose. Crankshaft angle sensor is used to measure the degree of rotation of crankshaft so as to control the ignition timing and therefore fuel injection rate. The sensors send signals to electronic control unit 4 which after receiving and processing these input signals, calculates the mass of fuel to be supplied to the engine. Fuel sensors 12 are employed which calculate the volume of fuel required to be converted to mass by the control unit by using the density of fuel. To ensure that the engine 6 is working within safe limits, output signals received from engine temperature sensors 14 (not shown) are processed by the electronic control unit 4. Similarly, electronic control unit 4 maintains the gearbox temperature within safe limits by processing the input signals 16 received from the gearbox temperature sensors.
The invention aims at running the vehicle 10 in a specific driving pattern as per the user's requirement and at the same time excluding user interference with the set driving patterns. The electronic control unit 4 for is calibrated for two specific sets of driving pattern also referred to as driving modes. These driving modes comprise of calibration charts 20 and 21 consisting of speed versus torque curve for each gear and throttle input position. Each of the calibration charts is optimized for maximum fuel efficiency and minimizing unwanted emissions. Hence the electronic control unit 4 is equipped with two calibration charts for preset modes, one which is derived from sporty driving conditions i.e. power mode 31 which has no speed limits and no torque limits on the engine at any gear whereas the second calibration chart i.e. fuel economy mode 30 is derived from the most fuel efficient driving pattern with constant throttle inputs with torque limiters for particular speeds and gears. Unlike existing prior art technologies, these calibration charts are stored within the electronic control unit and not externally. This is advantageous since storing the calibration charts within electronic control units is more reliable than an external device. An external device is liable to be mechanically damaged due to atmosphere and usage. Furthermore, no

additional hardware is required minimizing complexity and costs of manufacturing costs to consumer.
The present invention does not rely on electronic control unit 4 to decide the mode but instead permit the user to switch between the two modes 30 and 31 depending on the existing driving conditions. The changeover between fuel economy mode 30 and power mode 31 or vice-versa is achieved through a selection switch 1. Referring to FIGs I and II, where the vehicle 10 comprises of the engine management system 11 of the invention including the electronic control unit 4 which receives signal inputs 16 from various sensing means. The vehicle 10 also comprises of the accelerator pedal 2 fitted with a position sensor 18 brake system 3, instrument cluster 5, engine 6, road wheel 7, mode indicators 19 and fuel sensors 12. The selection switch 1 enables the user to select logic to be used for driving the vehicle 10 and allows the driver to enter his input request. In one embodiment, the selection switch 1 is provided on the dashboard near the air-conditioner of the vehicle. However, the selection switch 1 may be placed at any suitable position which is easily accessible to the driver. The switch may be a single pole double throw (SPDT) switch or a push button or a lever or any other suitable witch with the proviso that it selects only one mode at a particular time thus ensuring failsafe operation. It can be understood that one mode will always be active. The switch 1 is routed through wiring harness and terminated at electronic control unit 4 as a digital input Whenever, there is open circuit because of wire cut or switch connection error, the electronic control unit 4 will direct the engine 6 towards power mode calibration chart 21. Referring to Fig III, it can be noted that power mode 31 is always the default mode. Whenever the driver selects the intended mode i.e. the fuel economy mode 30, the electronic control unit 4 will follow the calibration chart 20 for this intended mode. Therefore, the power mode 31 is also considered as the normal running mode. There is no supervisory control in this mode. Electronic control unit 4 functions as per normal operations which include deciding the fuel injection rate and torque control based on accelerator pedal sensor 18 inputs.
A mode indicating means 19 are employed which keeps the user informed about the mode in which the vehicle is running. In one embodiment, there are two lamps indicating 'GREEN' for fuel economy mode and 'RED' for power mode. The lamps are mounted In the instrument cluster or any other suitable position where they are

clearly visible to the user. It is to be noted that only one lamp will be lit at one time, Although in an alternate embodiment any suitable mode indicators may be employed which indicate the selected mode to the user.
Example 1: Switching from Power mode to Fuel Economy mode:
Referring to FIG. III, with the first crank, default power mode will be active. Now the driver input for selecting the fuel economy mode 30. The electronic control unit 4 will perform a check across all pre defined requirements to maintain stability and safety of the vehicle by measuring a plurality of engine and operating parameters. Depending upon the error flags generated, the control unit 4 will automatically adjust the engine parameters including fuelling rate, torque profile etc. If the vehicle speed is more than the speed predefined in the electronic control unit, then the speed of the vehicle will be dropped down with a certain deceleration factor. For example, (Factor (Y)= 0.4246X2-16.066X + 200 where Y is speed & X is the time). This factor will different for different vehicles, the factor will defined at the time of preparing calibration chart for fuel economy and power mode. Following which the electronic control unit 4 will be operational as per the preset calibration chart 20 for fuel economy mode 30.
Example 2: Switching from Fuel Economy mode to Power mode:
Now, considering that a vehicle is running in Fuel Economy mode 30 and the driver switches over to power mode 31. Therefore the electronic control unit 4 performs a check across all pre defined requirements to maintain stability and safety of the vehicle by measuring a plurality of engine and operating parameters. Depending upon the error flags generated, the control unit 4 will automatically adjust the engine parameters including fuelling rate, torque profile etc suitable to power mode. If the vehicle speed is more than the speed predefined in the electronic control unit, then the speed of the vehicle will be dropped down with a certain acceleration factor. For example, Factor (Y)= 0.4246X2-16.066X + 200 where Y is speed & X is the time). This factor will different for different vehicles, the factor will defined at the time of preparing calibration chart for fuel economy and power mode. Following which the electronic control unit 4 will be operational as per the preset calibration chart 21 for power mode 31.

Example 3: Automatic transmission vehicles: Power mode to fuel economy mode:
In case of automatic transmission vehicles, change in gear ratio depends on throttle position and vehicle speeds. To achieve fuel economy mode for automatic transmission, engine 6 has to be operated within specified speed range (fixed torque values) for each transmission mode. After receiving driver's input request through the selection switch 1, the speed is measured through flywheel speed sensor 13 (not shown) and gearbox output shaft sensor 17 (not shown) and signals are sent to electronic control unit 4. These input signals 16 are processed and speed is adjusted by ratio-up shift or downshift to deliver the necessary torque and to maintain the speed accordingly. (FIG V)
Hence after selecting the fuel economy mode, the electronic control unit 4 will change the fuel quantity to be injected with due considerations of safety provisions to ensure the healthiness of engine performance using engine monitoring sensors namely flywheel sensors 13, fuel flow sensors 12, cam sensors 14, crankshaft angle sensors 15, fuel to air ratios etc.
If running the vehicle in power mode, the driver wants to switch over to fuel efficiency mode, then, within safety provisions, engine management system overrides the power mode and changes the fuel rate to fuel economy mode. With this torque limiter cum speed controller, fuel economy is achieved. Such process is completely reversible instantly.
Example 4: To achieve the most fuel efficient calibration chart for fuel efficiency mode on road dynamometer trials were conducted to arrive at optimized fuel efficiency calibration chart by restricting the engine torque in turn maximum vehicle speed in each gear. The results are plotted as curves in FIGs IVa and IVb .
As is evident from afore described experiments, the preset modes allow the driver to switch modes in real time i.e. when the vehicle is in transit. The calibration charts for the preset modes i.e. fuel economy mode and power mode are advantageously provided within the electronic control unit and not externally. The existing prior arts

include the fuel maps external to electronic control unit which is liable to mechanical damage due to exposure to atmosphere and usage. Thus by incorporating the calibration charts within the electronic control unit the present invention avoids complexity by avoiding an external component and advantageously provides simple machinery at reduced costs both to the manufacturer as well as the consumer. By providing a selection switch the user and not electronic control unit decide the driving mode based on actual driving conditions. The engine management system of the present invention permits maximum fuel economy without compromising on safety or stability of the vehicle. The engine management system comprising of the electronic control unit provides maximum fuel economy with reduced emissions of poisonous gases such as carbon dioxide, carbon monoxide.
It is to be noted that the invention is explained above with the help of an exemplary embodiment which is presented for the purpose of illustration and description in order to explain the various principles of the invention and their practical application. This is not intended to exhaust or limit the invention to a precise form that is disclosed and obviously many modifications and variations are possible in the light of the above teachings.

We claim:
1. An engine management system for an internal combustion engine comprising
of:
Sensing means for measuring plurality of engine and vehicle operating
conditions in real time,
Electronic Control Unit (ECU) for receiving inputs for measurements from
the sensing means, receiving driver input request, for adjusting fuelling
parameters including fuel injection rate, torque control depending on
request input by the driver,
Calibration charts for preset modes optimized for speed versus torque curve
for each gear and throttle input position,
the calibration charts for preset modes are stored within the electronic
control unit.
2. The engine management system as claimed in claim 1, wherein the preset modes include fuel economy mode and power mode.
3. The sensing means as claimed in claim 1, wherein the sensing means include flywheel speed sensor, gearbox shaft speed sensor, crankshaft angle sensor, engine temperature sensors, fuel flow sensors, gearbox temperature sensors, position sensor.
4. The engine management system as claimed in claim 1 comprises of selection switch provided for the driver to enter his input request.
5. The engine management system as claimed in any of the preceding claims wherein the engine management system comprises of mode indicating means provided for indicating the selected mode to the driver.
6. A method for switching from power mode to fuel economy mode, said method comprising steps of:
a. Receiving driver's input request entered with a selection switch.
b. Measuring a plurality of engine and vehicle operating conditions.
c. Adjusting the engine parameters including fueling parameters such as fuel
rate, torque profile and reducing speed with a deceleration factor.

d. After attaining the desired levels of each operating parameter, operating as per calibration charts stored for fuel economy mode.
7. A method for switching from fuel economy mode to power mode, said method
comprising steps of:
a. Receiving driver's input request entered with the selection switch.
b. Measuring plurality of engine and vehicle operating conditions.
c. Adjusting engine parameters including fueling parameters such as fuel rate,
torque profile and increasing speed with an acceleration factor.
d. After attaining the desired levels for each operating parameter, operating as
per calibration charts stored for power mode.
8. A method for switching modes in an engine management system for automatic
transmission, said method comprising steps of:
a. Receiving driver's input request
b. Measuring speed through flywheel speed sensor and gearbox output shaft
sensor measure speed and sending output signals to electronic control unit.
c. Receiving input signals at electronic control unit and adjusting speed to
upshift or downshift from one of the plurality of mechanical gear ratios.
9. The engine management system for an internal combustion engine as described in detailed description and examples hereinabove.
10. A vehicle comprising the engine management system for internal combustion engine as claimed in any of the preceding claims.