GEAR SHIFT INDICATION SYSTEM AND METHOD THEREOF
FIELD OF THE INVENTION
The present invention relates to the field of vehicle gear shifting systems. The present invention specifically relates to a system and method for indicating optimal transmission gear shift to a vehicle driver.
BACKGROUND OF THE INVENTION
In general, vehicle engine performance is a primary focus of automotive development, where the engine performance mainly depends on optimal gear shifting. Optimal gear shifting includes shifting gears within a range of maximum engine power, which enables the vehicle to maintain an optimal rate of acceleration and avoid overburdening the vehicle engine. Normally, a manual transmission shifts gears according to an operation of a driver. In such manual transmission, the driver can select any gear, i.e. gear ratio. Therefore, the gear selected by the driver may not be effective always in regard to engine power and fuel consumption of the vehicle, because usually the driver makes error on the precise moment to shift the gears.
In order to overcome improper gear shifting due to driver error, the vehicles are provided with a gear shift Indicator that indicates to the driver a gear shift to the gear determined in consideration of engine power and fuel consumption of the vehicle. When the driver finds that the shift indicator is turn on, the driver recognizes that the current gear should be shifted to optimal gear position. Conventional shift indication systems and automatic transmission controllers select the optimal gear position in accordance with online/real-time

computation of torque, injected quantity based on computation tables and determination of advised gear based on fuel consumption. However, the conventional shift indication systems provide optimal gear indication to the driver, but it requires more computational cost and time to response to the driver, since it does iterative computations with multiple vehicle parameters at each time interval to decide on the optimal gear shift points, which results in time delay in providing gear shift indications as well as increase in computational cost.
Moreover, these gear shift advisory systems and methods utilize complex computational logic and requires multiple inputs like vehicle speed, engine speed, throttle position, engine torque and quantity of fuel injected, to decide on the optimal gear shift points. This process involves huge computational task such as multiple table look ups, interpolations and extrapolations to be performed iteratively and computational overhead in determining fuel consumption of current gear and target gears. Moreover, there would be multiple look up tables to compute the engine torque and injected fuel quantity at the current gear, and torque and fuel consumed at all other possible gears, to decide on the optimal gear shift point.
With respect to the conventional approaches, it should be apparent that a need exists for a real-time optimal gear shift indication method with less number of look up tables and computational task. Some of conventional systems utilize minimum inputs like vehicle speed, engine speed and throttle position, but it also performs even heavy computations. Since the entire computation is done internally, the memory requirement is very high and complexity of the software used in these systems is also very high, which increases the overall cost of these systems. Therefore, it is desirable to provide a system and method for indicating optimal transmission gear shift to a vehicle driver, which is capable to overcome all of the above-discussed shortcomings in the art.

OBJECT OF THE INVENTION
An object of the present invention is to provide a system for indicating optimal transmission gear shift to a vehicle driver, which improves fuel economy and driving pattern of the driver during transportation.
Another object of the present invention is to provide a system for indicating optimal transmission gear shift to a vehicle driver, which reduces computation time, memory requirement and computation cost for gear shift indication.
Yet another object of the present invention is to provide a method for indicating optimal transmission gear shift to a vehicle driver, which eliminates the need of complex on-line computations with real-time vehicle parameters involved in gear shift indication.
Yet another object of the present invention is to provide a system for indicating optimal transmission gear shift to a vehicle driver, which reduces overall system cost due to less complexity in the software and hardware.
SUMMARY OF THE INVENTION
According to one aspect, the present invention, which achieves this objective, relates to a system for indicating optimal transmission gear shift to a vehicle driver, comprising: a control unit associated with one or more sensors or controller area network (CAN) for obtaining and processing engine speed, vehicle speed and throttle position. A storage unit is configured for storing an advised gear lookup table and constants for computations. A microprocessor is in communication with the control unit and the storage unit for computing and determining actual gear based on the engine speed, the vehicle speed and the throttle position along with the constants. The microprocessor selects timer for

gear advice after computing a driver demand. A power supply unit is connected with a battery for supplying power to the control unit and the microprocessor. The microprocessor compares the computed actual gear with an optimal gear recommended in the advised gear lookup table for that instance in relation to the engine operating mode, such that the optimal gear shift Is indicated to the vehicle driver, based on the timer, which is selected based on the driver demand, if the actual gear is not equal to the optimal gear of the advised gear lookup table. Thus, the system improves fuel economy and driving pattern of the driver and reduces computation time, memory requirement and computation cost for gear shift indication.
Furthermore, the microprocessor selects the optimal gear from the advised gear lookup table based on the engine operating mode. The constants comprise gear ratio, rear axle ratio and tyre rolling radius. The engine operating mode comprises economy mode and power mode. The advised gear lookup table is computed offline based on specific combinations of the vehicle speed, the engine speed and the throttle position for both the economy and power modes of the vehicle engine. For economy mode, the optimal gear in the advised gear lookup table is computed based on gear with lowest specific fuel consumption (SFC) corresponding to the vehicle speed and the throttle position. Similarly, for power mode, the optimal gear in the advised gear lookup table is computed based on gear with highest gear transmission torque at wheels corresponding to the vehicle speed and the throttle position.
In addition, the microprocessor is associated with an output unit for indicating the optimal gear shift to the vehicle driver. The output unit comprises up LED, down LED, audio beeper and compliance level indicator. If the computed current gear matches with the optimal gear recommended in the advised gear lookup table, no advice is provided to the driver. If the actual gear is lesser than the optimal gear recommended in the gear lookup table, the microprocessor actuates the up LED to indicate the vehicle driver to shift up the

actual gear in accordance with the recommended optimal gear. The LED indication is provided to the driver based on the timer selected w/ith respect to the current driver demand.
Moreover, if the actual gear is higher than the optimal gear recommended in the gear lookup table, the microprocessor actuates the down LED to indicate the vehicle driver to shift down the actual gear in accordance with the recommended optimal gear. The microprocessor actuates the audio beeper to provide audio beep to the vehicle driver, if the optimal gear shift indication is not followed by the vehicle driver for a specified duration. The microprocessor also computes the drive compliance to the shift advisory system based on whether the driver is following to the advice provided by the shift advisory system and updates the compliance percentage in the system memory, which can be instantaneously displayed to the driver through the compliance level indicator or send to a remote server for driver performance measurement and analysis. Hence, the system can be integrated to an on board telematics unit for sending real time computational data to a backend server for remote vehicle monitoring and fleet management. Also, such system can be integrated with an automatic gear shift controller, so that the actual gear is automatically shifted in relation to the optimal gear shift advise from the microprocessor.
According to another aspect, the present invention, which achieves this objective, relates to a method for indicating optimal transmission gear shift to a vehicle driver, comprising: obtaining vehicle speed, engine speed and throttle position from a vehicle during transportation. Actual gear Is computed based on the engine speed and the vehicle speed along with constants of a vehicle model. Optimal gear recommended in the advise gear lookup table is determined in accordance with the selected operating mode and timer is selected based on the computed driver demand. Comparison is made whether the computed actual gear matches with the optimal gear recommended in the lookup table. Optimal gear shift is indicated to the vehicle driver based on the timer, if the actual gear is

not equal to the optimal gear in the advised gear lookup table. Audio beep Is provided to the vehicle driver, if the optinnal gear shift Indication is not followed by the vehicle driver for specified time duration. Driver's compliance to the optimal gear shift indication is computed in parallel and which can be considered as a measure of driver adherence to the system. This information can be instantaneously displayed to the driver through a compliance level indicator or sent to a remote server for driver performance measurement and analysis.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be discussed in greater detail with reference to the accompanying Figures.
FIG. 1 illustrates a system for indicating optimal transmission gear shift to a vehicle driver, in accordance with an exemplary embodiment of the present invention; and
FIG. 2 illustrates a flow diagram of a method for indicating optimal transmission gear shift to a vehicle driver, in accordance with an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a system for indicating optimal transmission gear shift to a vehicle driver is illustrated, in accordance with an exemplary embodiment of the present invention. The system can process the input parameters and carry out the required computations designed to fully meet the requirements and the specifications of the vehicle. The system is equipped with an input unit (101), a control unit (102), a mode selection unit (103), a storage unit (104), a microcontroller (105), an output unit (106), a communication interface (107), a programming interface (108), a power supply unit (109) and a battery (110). The

input unit (101) can acquire and process input signals such as engine speed, vehicle speed and throttle data, via a controller area network (CAN) or through sensors to perform gear shift indication function. These input signals are acquired in a real time manner, i.e. during transportation. In case of CAN, the input signals are obtained from a vehicle CAN bus. In case of sensors, the input signals are obtained via hardware signal wires.
Further, the acquired input signals are directly conveyed to a control unit (102), where the control unit (102) can be a CAN controller (102a) or a signal conditioning module (102b) depending upon the requirements. If the input signals are received from the CAN bus, then the CAN controller (102a) interfaced to the input unit (101) processes the input signals before transmitting it to the microcontroller (105). If the input signals are received from the sensors, then the signal conditioning module (102b) interfaced to the input unit (101) processes and conditions the input signals before transmitting it to the microcontroller (105). The mode selection unit (103) can directly be connected with the microcontroller (105), which provides an option to the driver or user to select an engine operating mode, i.e. mode of operation between power mode and economy mode.
Initially, predetermined gear lookup tables, timer values and constants like actual gear ratios, rear axle ratio and tyre rolling radius, are stored in the storage unit (104) e.g. EEPROM (Electronically Erasable Programmable Read-Only Memory). The gear ratios, tyre rolling radius and rear axle ratio are constant for a specific vehicle model. The storage unit (104) is connected with the microcontroller (105) for communicating the gear lookup tables, the timer values and the constants to the microcontroller (105). The advice gear lookup tables are computed offline using apriori approach, which carries optimal transmission gear for the present vehicle speed and throttle data. Such predetermined advised gear lookup table creation is carried out in relation to the engine operating mode, i.e. power mode and economy mode, for a specific combination of vehicle speed and

pedal position. Such off-line computation of the optimal gear can be utilized for any power train configuration.
Moreover, the computation and creation of gear lookup tables used in the present invention is clearly and elaborately described in prior co-pending Indian Patent Application No. 2480/CHE/2009, "Method for off-line determination of optimal transmission gear for a vehicle", filed on 12 October 2009, which is assigned to the same applicant as the present invention. The fundamental determination process described in the co-pending application involves creation of the optimal gear tables in relation to different combinations of the vehicle speed, the engine speed and the throttle data for both the economy and power modes of the vehicle engine. The disclosure of the aforementioned co-pending Indian Patent application is incorporated herein by reference.
The engine speed, vehicle speed and throttle data are processed and then fed to the microcontroller (105) for performing the required computations. The microcontroller (105) is in communication with the control unit (102) and the storage unit (104). The microcontroller (105) computes and determines current gear of the vehicle. For computing the current gear, the constants stored in the storage unit (104) are used along with the instantaneous vehicle speed and engine speed data. The microcontroller (105) is coupled with the RAM (105a) for temporary storage of the vehicle parameters and the processed output signals, i.e. current gear, advised gear, compliance, etc.
Furthermore, the microcontroller (105) selects the recommended optimal gear for current operating condition from the static advice gear table, whose generation is described in the aforementioned co-pending application, stored in the storage unit (104). Such optimal gear tables can be utilized by the system for determining the gear shift point. The microcontroller (105) selects the gear lookup table based on the selection of the mode of operation, i.e. power or economy. In economy mode, lowest specific fuel consumption (SFC) is used for
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selecting the best operating point. In such condition, the gear number in the gear table corresponds to best gear for operating the vehicle to get better fuel economy. Similarly, in power mode, maximum torque at wheels is used for selecting the best operating point, which may not be the optimal operating point in term of fuel economy. In such condition, the gear number in the gear table corresponds to best gear for operating the vehicle to deliver maximum torque at wheels.
The microcontroller (105) compares the computed current gear with the optimal gear recommended in the advice gear lookup table based on the selected mode of operation. If the current gear matches with the optimal gear recommended in the gear lookup table, then the microcontroller (105) again computes and compares the current gear with the optimal gear recommended in the gear lookup table, after a predetermined time period. Similarly, if the current gear does not matches with the recommended optimal gear selected for the particular operating point, then the microcontroller (105) indicates the driver using the output unit (106) to shift up or down the gear in accordance with the recommended optimal gear. The output unit (106) can be configured with a light emitting diode (LED) indicator such as up LED (106a) and down LED (106b), audio beep unit (106c) and compliance level indicator (106d).
Moreover, if the current gear is lesser than the recommended optimal gear in the lookup table, the microcontroller (105) actuates the up LED (106a) to indicate the driver to shift up the current gear to be identical with the recommended optimal gear. Similarly, if the current gear is higher than the recommended optimal gear in the lookup table, the microcontroller (105) actuates the down LED (106b) to indicate the driver to shift down the current gear to be identical with the recommended optimal gear. For providing the advice, the driver demand is also considered as an important parameter. The gear is selected from the static gear table and indicates the shift advice to the driver based on the vehicle speed, throttle percentage and the timer value, where

the timer is selected based on computed driver demand. The microcontroller (105) actuates the audio beep unit (106c) for providing audio beep to the driver after the predefined time for the gear shifting, if the advice of gear shift indication is not followed by the driver. The microcontroller (105) also computes and indicates gear compliance level using the compliance level indicator (106d), which indicates the driver's adherence to the gear shift indication system and is represented in terms of percentage. Thus, the system is equipped with the provision to display the shift indication by the LEDs (106a, 106b), audio beep by the beeper module (106c) and the driver compliance display (106d).
The communication interface (107) and the programming interface (108) enables the system to easily interface with electronic control units with wireless communication modules (GSM/GPRS) for transmission of data to a remote server/location. The driver's compliance to the system advice is also being computed apart from the gear advice indication, which can be displayed, logged and/or sent to a remote server for driver performance measurement and analysis. The power supply unit (109) is connected with the battery (110), preferably vehicle battery, which provides the power supply to the components of the system. The entire system can also be integrated with automatic gear shift controller, so that the automatic gear shift controller shifts the gear automatically in accordance with the gear shift advice from the microprocessor (105).
Further, the system can easily be integrated into and with instrument cluster as the input for the system is already available at cluster for gauge display. Since the input signal processing is already done in the cluster, the input processing and power management module can be removed from the system. The system can also use the LED's available in the cluster to display the gear shift indication. Othenwise, the cluster can be provided with additional LED's for displaying the Up shift and Down shift. Audio beeper can also be removed from the system and can be integrated to beeper in the cluster. With in integration of the system with the cluster, only the additional computational logic has to be

done by the cluster as the input and output module of the cluster can be adopted. This reduces the cost of the systenn and also the mounting space for the system and wiring connections. The compliance level in percentage can also be displayed in the cluster, if an LCD panel is available in the cluster.
The gear shift advisory system is intended for automotive applications. Such system can be integrated to an On Board Telematics unit, which sends the real time computational data from the system to a backend server for remote vehicle monitoring and management. In this case, gear compliance can be sent to the backend and made available to the fleet owners along with the vehicle location information for effective fleet management and driver performance monitoring. The system can be used across all vehicle platforms including commercial vehicles by configuring the respective offline gear tables and vehicle constants. Since the major computation of selecting the optimal gear for a given operating point is computed offline and stored in the storage unit (104), thus the computation time and memory requirement of the system are reduced.
Such system is designed to advise the driver to drive in most optimal gear in order to improve the fuel economy and driving pattern of the driver. The system does real time engine data acquisition and performs a simple algorithm to compute the optimal gear and recommends the gear shift indication to the driver. The system requires only minimal inputs such as vehicle speed, engine speed and throttle percentage, to perform the gear shift advice function. Thus, the processing time to compute and display the gear shift indication is reduced as it performs very less computation. The system uses simple logic to execute the gear shift indication, and thus reduces complexity of the software and hardware, which effectively reduces the overall cost of the system.
Referring to FIG. 2, a flow diagram of a method for indicating optimal transmission gear shift to a vehicle driver is illustrated, in accordance with an exemplary embodiment of the present invention. As illustrated in step 201,

vehicle speed, engine speed, throttle position and operating mode are obtained from the vehicle during transportation. As depicted in step 202, current gear (CG) is computed using the vehicle speed and the engine speed along with the constants. The constants like actual gear ratios, rear axle ratio and tyre rolling radius, are stored in the flash memory. As specified in step 203, advice gear (AG) recommended in an advised lookup table is determined in accordance with the selected operating mode, vehicle speed and throttle percentage. The advice gear lookup table is stored in the flash memory. Then, timer can be selected after computing the driver demand, as mentioned in step 204.
Further, as indicated in step 205, checking is made whether the current gear (CG) matches with the advice gear (AG) in relation to the selected operating mode. If the current gear (CG) matches with the advice gear (AG) recommended in the advice gear lookup table, then the step 201 is repeated. If the current gear (CG) is not equal to the advice gear (AG), then checking is made whether the advice gear (AG) is greater than the current gear (CG), as depicted in step 206. As illustrated in step 207, if the advice gear (AG) is greater than the current gear (CG), then up LED and audio beeper is actuated based on the timer, which indicates the driver to shift up the current gear (CG) to be identical with the advice gear (AG). Similarly, as specified in step 208, if the advice gear (AG) is lesser than the current gear (CG), then down LED and audio beeper is actuated based on the timer, which indicates the driver to shift down the current gear (CG) to be identical with the advice gear (AG). As indicated in step 209, gear compliance is calculated based on whether the driver is following to the shift advisory system. Finally, the process is repeated in fixed time interval.
The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the claimed invention. Various modifications and alterations to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the claimed

invention. Thus, the claimed invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

WE CLAIM:
1. A system for indicating optimal transmission gear shift to a vehicle driver,
comprising:
a control unit associated with one or more sensors or controller area networl< (CAN) for obtaining and processing engine speed, vehicle speed and throttle position;
a storage unit configured for storing an advised gear lookup table and constants of a vehicle model;
a power supply unit connected with a battery for supplying power to said control unit; and
a microprocessor in communication with said control unit and said storage unit for computing and determining actual gear based on the engine speed and the vehicle speed along with the constants, said microprocessor sets timer for gear advice after computing driver demand,
wherein said microprocessor compares the computed actual gear with an optimal gear recommended in said advised gear lookup table in relation to the engine operating mode, such that optimal gear shift is indicated to the vehicle driver, based on the timer, which is selected based on the driver demand, if the actual gear is not equal to the optimal gear of said advised gear lookup table.
2. The system as claimed in claim 1, wherein said microprocessor selects the optimal gear from said advised gear lookup table based on the engine operating mode.
3. The system as claimed in claim 1, wherein the constants comprise gear ratio, rear axle ratio and tyre rolling radius.
4. The system as claimed in claim 1, wherein the engine operating mode comprises economy mode and power mode.

5. The system as claimed in claim 1, wherein said advised gear lookup table is computed offline based on specific combinations of the vehicle speed and the throttle position for both the economy and power modes of the vehicle engine.
6. The system as claimed in claim 5, wherein for economy mode, the optimal gear in said advised gear lookup table is computed based on gear with lowest specific fuel consumption (SFC) corresponding to the vehicle speed and the throttle position.
7. The system as claimed in claim 5, wherein for power mode, the optimal gear in said advised gear lookup table is computed based on gear with highest gear transmission torque at wheels corresponding to the vehicle speed and the throttle position.
8. The system as claimed in claim 1, wherein said microprocessor is associated with an output unit for indicating the optimal gear shift to the vehicle driver.
9. The system as claimed in claim 1, wherein said output unit comprises up LED, down LED, audio beeper and compliance level indicator.
10. The system as claimed in claim 1, wherein the system is integrated with an instrument cluster.
11. The system as claimed in claim 1, wherein if the actual gear matches with the optimal gear recommended in said preset gear lookup table, said microprocessor repeats computation.
12. The system as claimed in claim 1, wherein if the actual gear is lesser than the optimal gear recommended in said gear lookup table, said microprocessor

actuates the up LED to indicate the vehicle driver to shift up the actual gear In accordance with the recommended optimal gear.
13. The system as claimed in claim 1, wherein if the actual gear is higher than the optimal gear recommended in said gear lookup table, said microprocessor actuates the down LED to indicate the vehicle driver to shift down the actual gear in accordance with the recommended optimal gear.
14. The system as claimed in claim 1, wherein said microprocessor actuates the audio beeper to provide audio beep to the vehicle driver, if the optimal gear shift indication is not followed by the vehicle driver for a set duration of time.
15. The system as claimed in claim 1, wherein said microprocessor computes the driver compliance to the advisory system based on whether the driver is following to the advice provided by the system.
16. The system as claimed in claim 1, wherein said microprocessor stores and/or displays the driver compliance in terms of percentage through said compliance level indicator.
17. The system as claimed in claim 1, wherein said control unit comprises a CAN controller or signal conditioning module.
18. The system as claimed in claim 1, wherein the system is integrated with an automatic gear shift controller, so that the actual gear is automatically shifted in relation to the optimal gear shift advise from said microprocessor.
19. The system as claimed in claim 1, wherein the system is integrated to an on board telematics unit for sending real time computational data and driver's compliance to the optimal gear shift indication to a backend server for remote vehicle monitoring, fleet management and driver performance analysis.

20. A method for indicating optimal transmission gear shift to a vehicle driver,
comprising:
obtaining vehicle speed, engine speed and throttle position from a vehicle during transportation;
computing actual gear based on the engine speed and the vehicle speed along with constants of a vehicle model;
determining optimal gear recommended in an advise gear lookup table in accordance with the selected operating mode and setting timer after computing a driver demand;
checking whether the computed actual gear matches with the optimal gear recommended in the lookup table; and
indicating optimal gear shift to the vehicle driver based on the timer, which is selected based on the driver demand, if the actual gear is not equal to the optimal gear in the advised gear lookup table.
21. The method as claimed in claim 20, further comprising:
providing audio beep to the vehicle driver, if the optimal gear shift indication is not followed by the vehicle driver; and
computing and sending driver's compliance to the optimal gear shift indication to a compliance level indicator and/or to a remote server for driver performance measurement and analysis.
22. The method as claimed in claim 20, wherein the constants comprise gear
ratio, rear axle ratio and tyre rolling radius.
23. The method as claimed in claim 20, wherein the engine operating mode
comprises economy mode and power mode.