Claims:
1. A method for controlling an overboost in a vehicle, the method comprises:
initiating (102), by an Engine Management System (EMS) (200), the overboost, on determining that a gas pedal in the vehicle has been pressed more than a predefined pressure level, currently selected gear is a gear other than a first gear and engine speed of the vehicle is equal to or greater than a first engine speed threshold; and
initiating (605), by the EMS (200), a timer, on initiating the overboost.

2. The method, as claimed in claim 1, wherein the method comprises ramping up, by the EMS (200), the overboost in an aggressive manner.

3. The method, as claimed in claim 1, wherein the method comprises inhibiting (103) the overboost, by the EMS (200), on determining that at least one of
the gas pedal has been pressed less than the predefined pressure level of its maximum range;
the timer has expired;
the engine speed has reached a second engine speed threshold;
inhibit conditions from boost pressure control;
operational limits of engine coolant temperature;
operational limits of exhaust temperature;
major spark retardation by knock control;
operational limits of charge temperature; and
operational limits of ambient pressure.

4. The method, as claimed in claim 3, wherein the method comprises ramping down, by the EMS (200), the overboost in a gradual manner.

5. An Engine Management System (EMS) (200) in a vehicle, said EMS (200) configured for:
initiating an overboost, on determining that a gas pedal in the vehicle has been pressed more than a predefined pressure level, a currently selected gear is a gear other than a first gear and engine speed of the vehicle is equal to or greater than a first engine speed threshold; and
initiating a timer, on initiating the overboost.

6. The EMS, as claimed in claim 5, wherein the EMS (200) is configured to ramp up the overboost in an aggressive manner.

7. The EMS, as claimed in claim 5, wherein the EMS (200) is configured to inhibit the overboost on determining that at least one of
the gas pedal has been pressed less than the predefined pressure level of its maximum range;
the timer has expired;
the engine speed has reached a second engine speed threshold;
inhibit conditions from boost pressure control;
operational limits of engine coolant temperature;
operational limits of exhaust temperature;
major spark retardation by knock control;
operational limits of charge temperature; and
operational limits of ambient pressure.

8. The EMS, as claimed in claim 7, wherein the EMS (200) is configured to ramp down the overboost in a gradual manner.
, Description:TECHNICAL FIELD
[001] Embodiments disclosed herein relate to vehicle drivability and more particularly in improving the drivability of a vehicle, wherein the vehicle is equipped with an overboost function.

BACKGROUND
[002] For turbocharged direct injection engines, during dynamic driving conditions, a specific boost pressure (air charge) and fueling is set. The fueling can depend on the user inputs, received through the gas pedal.
[003] To provide an increase in vehicle drivability performance, an additional boost pressure (maximum air charge) and corresponding fueling is set for a fully pressed gas pedal, which enables differentiated vehicle performance in comparison with normal performance delivery. This increased maximum power in dynamic driving condition is called overboost.
[004] Currently, the overboost function is activated by strongly pressing the gas pedal in any gears and the overboost function is deactivated, when the gas pedal is released and when the maximum duration of overboost activation time is completed (overboost control). The overboost time is calculated from driven idle speed (i.e., minimum vehicle speed in a specific gear required to move the vehicle), when the gas pedal is strongly pressed. This limits the overboost function to higher gears (for example, the 4th gear, the 5th gear and the 6th gear) at widely used mid-range engine speeds (for example, 2000 - 3000 rpm (revolutions per minute)). There are also a limited set of inhibition conditions based on boost control, engine coolant temperature, exhaust temperature and knock control.

OBJECTS
[005] The principal object of embodiments herein is to disclose methods and systems for improving drivability performance of a vehicle during dynamic driving conditions, when overboost is active.
[006] Another object of embodiments herein is to disclose methods and systems for activating overboost only in specific gears above a pre-defined engine speed threshold while meeting thermodynamic boundary conditions, on a user of the vehicle pressing the accelerator pedal beyond a pre-defined threshold and the activation time of the overboost function is calculated from the time at which speed of the engine of the vehicle reaches the pre-defined engine speed threshold.
[007] Another object of embodiments herein is to disclose methods and systems for inhibiting overboost based on conditions comprising boost control, engine coolant temperature, exhaust temperature, knock control, intake manifold temperature and ambient pressure.
[008] These and other aspects of the embodiments herein will be better appreciated and understood when considered in conjunction with the following description and the accompanying drawings. It should be understood, however, that the following descriptions, while indicating at least one embodiment and numerous specific details thereof, are given by way of illustration and not of limitation. Many changes and modifications may be made within the scope of the embodiments herein without departing from the spirit thereof, and the embodiments herein include all such modifications.

BRIEF DESCRIPTION OF FIGURES
[009] Embodiments herein are illustrated in the accompanying drawings, through out which like reference letters indicate corresponding parts in the various figures. The embodiments herein will be better understood from the following description with reference to the drawings, in which:
[0010] FIG. 1 is a flowchart depicting the process of controlling the overboost function in a vehicle, according to embodiments as disclosed herein;
[0011] FIG. 2 depicts an Engine Management System (EMS) in a vehicle, according to embodiments as disclosed herein;
[0012] FIG. 3 depicts the overboost being initiated, according to embodiments as disclosed herein;
[0013] FIG. 4 depicts an example, where the overboost is initiated, according to embodiments as disclosed herein;
[0014] FIG. 5 is an example depicting a comparison of the engine speed versus torque, when the overboost is active and inactive, according to embodiments as disclosed herein;
[0015] FIG. 6 is a flowchart depicting the process of initiating the overboost function, according to embodiments as disclosed herein;
[0016] FIG. 7 depicts the inhibition of the overboost, according to embodiments as disclosed herein;
[0017] FIG. 8 is an example depicting the inhibition of the overboost, according to embodiments as disclosed herein;
[0018] FIG. 9 is a flowchart depicting the process of inhibiting the overboost function, according to embodiments as disclosed herein;
[0019] FIG. 10 is a graph depicting the initiation and the inhibition of the overboost function, according to embodiments as disclosed herein;
[0020] FIGs. 11A and 11B depict a comparison between controlling overboost (as available currently) and overboost (using embodiments as disclosed herein) in the fourth gear respectively, according to embodiments as disclosed herein;
[0021] FIGs. 12A and 12B depict a comparison between controlling overboost (as available currently) and overboost (using embodiments as disclosed herein) in the fifth gear respectively, according to embodiments as disclosed herein; and
[0022] FIGs. 13A and 13B depict a comparison between controlling overboost (as available currently) and overboost (using embodiments as disclosed herein) in the sixth gear respectively, according to embodiments as disclosed herein.

DETAILED DESCRIPTION
[0023] The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.
[0024] The embodiments herein achieve methods and systems for improving drivability performance of a vehicle during dynamic driving conditions, when overboost is active. Referring now to the drawings, and more particularly to FIGS. 1 through 13B, where similar reference characters denote corresponding features consistently throughout the figures, there are shown embodiments.
[0025] Embodiments herein disclose methods and systems for improving drivability performance of a vehicle during dynamic driving conditions, when overboost is active. Embodiments herein disclose methods and systems for activating overboost only in specific gears above a pre-defined engine speed threshold while meeting thermodynamic boundary conditions, on a user of the vehicle pressing the accelerator pedal beyond a pre-defined threshold and the activation time of the overboost function is calculated from the time at which speed of the engine of the vehicle reaches the pre-defined engine speed threshold. Embodiments herein disclose methods and systems for inhibiting overboost based on conditions comprising boost control, engine coolant temperature, exhaust temperature, knock control, intake manifold temperature, charge temperature, ambient pressure, current gear, and so on.
[0026] FIG. 1 is a flowchart depicting the process of controlling the overboost function in a vehicle. In step 101, a check is made if all conditions required for initiating the overboost function have been satisfied. The conditions required for initiating the overboost function can be, but not limited to, the gas pedal being pressed over a threshold, the engine speed being over a threshold and the vehicle being in a gear other than the first gear. If all the conditions required for initiating the overboost function have been satisfied, the overboost function is activated and a timer is initiated (step 102). On the timer expiring or at least one condition for inhibiting the overboost function being satisfied (step 103), the overboost function is inhibited (step 104). In an embodiment herein, the overboost function can be inhibited across a ramp. The various actions in method 100 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 1 may be omitted.
[0027] FIG. 2 depicts an Engine Management System (EMS) in a vehicle. The vehicle can be any vehicle, which can be configured to operate with an overboost function. In an embodiment herein, the EMS 200 can be a dedicated control unit, wherein the EMS 200 controls only the overboost function. In an embodiment herein, the EMS 200 can be a generic control unit, wherein the EMS 200 performs one or more control functions related to the vehicle, in addition to controlling the overboost function.
[0028] The EMS 200 can receive inputs from one or more sensors and/or modules present in the vehicle. The EMS 200 can receive information from the sensors and/or modules, such as, but not limited to, inputs from the gas pedal, engine speed, currently selected gear, engine coolant temperature, exhaust temperature, knock levels, boost control, charge temperature, ambient pressure, and so on. Embodiments herein use the terms ‘gas pedal’, ‘accelerator’, ‘accelerator pedal’ interchangeably to refer to the pedal used by the user of the vehicle for controlling the acceleration of the vehicle.
[0029] The EMS 200 can initiate the overboost function for a pre-defined period of time based on inputs from the gas pedal, current engine speed and the currently selected gear (as depicted in FIG. 3). The EMS 200 can determine the pressure exerted on the gas pedal. On determining that the gas pedal has been pressed more than a predefined pressure level of its maximum range, the EMS 200 checks if the currently selected gear is a gear other than the first gear. In an embodiment herein, the gear can be selected automatically. In an embodiment herein, gear can be selected manually. If the currently selected gear is a gear other than the first gear, the EMS 200 checks if the engine speed is equal to or greater than a first engine speed threshold (which can be measured in revolutions per minute (rpm)). On the engine speed being equal to or greater than the first engine speed threshold, the EMS 200 initiates the overboost function. The overboost function can be ramped up in an aggressive manner, hereby providing power to the vehicle quickly. On initiating the overboost function, the EMS 200 initiates a timer, wherein the timer can be for a pre-defined period of time and the timer is initiated on the overboost function being initiated. The pre-defined period of time can depend on factors such as, but not limited to, engine characteristics, vehicle tuning, and so on.
[0030] In an example herein (as depicted in FIG. 4), on determining that the gas pedal has been pressed more than 70% of its maximum range, the EMS 200 checks if the currently selected gear is a gear other than the first gear. If the currently selected gear is a gear other than the first gear, the EMS 200 checks if the engine speed is equal to or greater than 1750 rpm. On the engine speed being equal to or greater than 1750 rpm, the EMS 200 initiates the overboost function. On initiating the overboost function, the EMS 200 initiates a timer for 21 seconds. The overboost function is available to the user of the vehicle for the duration of the timer for a time period in the engine speed range of 2000-3000 rpm (as depicted in the example in FIG. 5).
[0031] FIG. 6 is a flowchart depicting the process of initiating the overboost function. In step 601, the EMS 200 determines the pressure exerted on the gas pedal. On determining that the gas pedal has been pressed more than a predefined pressure level of its maximum range (step 602), in step 603, the EMS 200 checks if the currently selected gear is a gear other than the first gear. If the currently selected gear is a gear other than the first gear, in step 604, the EMS 200 checks if the engine speed is equal to or greater than the first engine speed threshold. On the engine speed being equal to or greater than the first engine speed threshold, in step 605, the EMS 200 initiates the overboost function and the timer. The various actions in method 600 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 6 may be omitted.
[0032] The overboost function can be inhibited to protect the engine and other components present in the vehicle (as depicted in FIG. 7). When overboost is active, the EMS 200 can monitor the pressure exerted on the gas pedal and check if the gas pedal has been pressed less than the predefined pressure level of its maximum range. The EMS 200 can further check if the timer has expired. The EMS 200 can check if the engine speed has reached a second engine speed threshold (measured in terms of rpm). The EMS 200 can also check for additional conditions such as, but not limited to, inhibit conditions from the boost pressure control, operational limits of the engine coolant temperature, operational limits of the exhaust temperature, major spark retardation by knock control, operational limits of the charge temperature, operational limits of the ambient pressure, currently selected gear, engine speed and so on. In an example, consider that overboost is active for the coolant temperature from 50 degrees Celsius to until 100 degrees Celsius. In an example, consider that overboost is active as long as the exhaust temperature is below 940 degrees Celsius. In an example, consider that overboost is active during spark retardation during knock control (5 degCA). In an example, consider that overboost is active till the charge temperature reaches 70 degrees Celsius. In an example, consider that overboost is active till the atmospheric pressure reaches 850 mbar. If the gas pedal has been pressed less than the predefined pressure level of its maximum range or if the engine speed has reached the maximum speed or if the timer has expired or at least one of the additional conditions is satisfied, the EMS 200 can inhibit the overboost function. The EMS 200 can ramp down the overboost in a gradual manner, so as to avoid the user feeling a significant difference in vehicle performance.
[0033] In an example (as depicted in FIG. 8), when overboost is active, the EMS 200 checks if the gas pedal has been pressed less than 70% of its maximum range. The EMS 200 further checks if the timer of 21 seconds has expired. The EMS 200 checks if the engine speed has reached the maximum speed of 3000 rpm. The EMS 200 can also check for additional conditions such as, but not limited to, inhibit conditions from the boost pressure control, operational limits of the engine coolant temperature, operational limits of the exhaust temperature, major spark retardation by knock control, operational limits of the charge temperature, operational limits of the ambient pressure, currently selected gear, engine speed and so on. If the gas pedal has been pressed less than 70% or if 21 seconds has expired or at least one of the additional conditions is satisfied, the EMS 200 inhibits the overboost function in a gradual manner.
[0034] FIG. 9 is a flowchart depicting the process of inhibiting the overboost function. When overboost is active, the EMS 200 checks if the gas pedal has been pressed less than the predefined pressure level of its maximum range (step 901). In step 902, the EMS 200 further checks if the timer has expired. In step 903, the EMS 200 checks if the engine speed has reached the maximum speed (measured in terms of rpm). In step 904, the EMS 200 also checks for additional conditions such as, but not limited to, inhibit conditions from the boost pressure control, operational limits of the engine coolant temperature, operational limits of the exhaust temperature, major spark retardation by knock control, operational limits of the charge temperature, operational limits of the ambient pressure, and so on. If the gas pedal has been pressed less than the predefined pressure level of its maximum range or if the engine speed has reached a maximum speed or if the timer has expired or at least one of the additional conditions is satisfied, the EMS 200 inhibits the overboost function in a gradual manner (step 905). The various actions in method 900 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIG. 9 may be omitted.
[0035] FIG. 10 is a graph depicting the initiation and the inhibition of the overboost function. Zone (a) in the graph indicates a first region, where there is no overboost. This can be because either the pressure on the accelerator pedal is less than the pre-defined pressure level or the vehicle is in the first gear or the engine speed is less than the first engine speed threshold. Zone (b) in the graph indicates a second region, where the overboost has been initiated and the overboost is ramped up in an aggressive manner. The overboost has been initiated on the pressure on the accelerator pedal being equal to or greater than the pre-defined pressure level and the vehicle is not in the first gear and the engine speed is not less than the first engine speed threshold. The timer has also been initiated at the beginning of zone (b). Zone (c) in the graph indicates a third region, where the overboost is active. Zone (d) in the graph indicates a fourth region, where the overboost is being inhibited. The overboost can be inhibited if the gas pedal has been pressed less than the predefined pressure level of its maximum range or the timer has expired or the engine speed has reached the second engine speed threshold, or inhibit conditions from the boost pressure control, or operational limits of the engine coolant temperature, or operational limits of the exhaust temperature, or major spark retardation by knock control, or operational limits of the charge temperature, or operational limits of the ambient pressure. The overboost is being ramped down in a gradual manner (as compared to the ramp up of the overboost (as in zone (b))). Zone (e) is a fifth region, where the overboost has been completely inhibited.
[0036] FIGs. 11A and 11B depict a comparison between controlling overboost (as available currently) and overboost (using embodiments as disclosed herein) in the fourth gear respectively.
[0037] FIGs. 12A and 12B depict a comparison between controlling overboost (as available currently) and overboost (using embodiments as disclosed herein) in the fifth gear respectively.
[0038] FIGs. 13A and 13B depict a comparison between controlling overboost (as available currently) and overboost (using embodiments as disclosed herein) in the sixth gear respectively.
[0039] Embodiments herein can improve the acceleration time of the vehicle by 5-10% over the current overboost logic. Embodiments herein can improve the in-gear acceleration of the vehicle against current overboost logic.
[0040] The embodiments disclosed herein can be implemented through at least one software program running on at least one hardware device and performing network management functions to control the network elements. The network elements shown in FIGs. 2, 3, 4, 7 and 8 include blocks which can be at least one of a hardware device, or a combination of hardware device and software module.
[0041] The embodiment disclosed herein describes methods and systems for improving drivability performance of a vehicle during dynamic driving conditions, when overboost is active. Therefore, it is understood that the scope of the protection is extended to such a program and in addition to a computer readable means having a message therein, such computer readable storage means contain program code means for implementation of one or more steps of the method, when the program runs on a server or mobile device or any suitable programmable device. The method is implemented in at least one embodiment through or together with a software program written in e.g. Very high speed integrated circuit Hardware Description Language (VHDL) another programming language, or implemented by one or more VHDL or several software modules being executed on at least one hardware device. The hardware device can be any kind of portable device that can be programmed. The device may also include means which could be e.g. hardware means like e.g. an ASIC, or a combination of hardware and software means, e.g. an ASIC and an FPGA, or at least one microprocessor and at least one memory with software modules located therein. The method embodiments described herein could be implemented partly in hardware and partly in software. Alternatively, the invention may be implemented on different hardware devices, e.g. using a plurality of CPUs.
[0042] The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of embodiments and examples, those skilled in the art will recognize that the embodiments and examples disclosed herein can be practiced with modification within the scope of the embodiments as described herein.