DESC:This application is based on and derives the benefit of Indian Provisional Application 4762/CHE/2015, the contents of which are incorporated herein by reference.

TECHNICAL FIELD
[001] Embodiments herein relate to energy management in vehicles, and more particularly to free energy recovery methods and systems for vehicles.

BACKGROUND
[002] A conventional vehicle powertrain comprises of a primary power source (PS1), flywheel, de-coupling mechanism and driveline including transmission, differential and axle system, which drive the wheels of the vehicle. Furthermore, various accessories and feed loads are connected to the primary power source (PS1) such as cooling pump, cooling fan, conventional brakes, power steering, and air conditioning systems etc.
[003] A hybrid vehicle combines a secondary power source (PS2) system, along with other conventional vehicle powertrain components, as described above, wherein some of the feed loads are being electrified. In case of a hybrid vehicle, it employs any suitable combination of conventional (e.g., hydraulic or friction) braking system and a secondary power source (PS2) based braking system during vehicle deceleration events. The conventional braking system typically includes several frictional drum or disc type braking assemblies, which can be selectively actuated by a hydraulic system. The secondary power source (PS2) based braking system basically includes system(s), which can provide negative power for vehicle deceleration and store the energy in any suitable form of energy storage device.
[004] During a vehicle slow down maneuver, a control system modulates the power requirement applied to the PS2 based braking in conjunction with conventional frictional braking assemblies in a manner that vehicle wheel slippage on the road surface is controlled. At present vehicles available (in market) with energy recovery has a decoupling mechanism between the primary power source and the secondary power source. This helps in reducing drag of primary power source PS1 (including inertial loss) on the energy recovery during vehicle slow down operation, but requires additional decoupling system and related control and also adds weight and related system cost.

OBJECTS
[005] The principal object of embodiments herein is to disclose methods and systems for free energy recovery in vehicles, when a decoupling device is not open.
[006] Another object of embodiments as disclosed herein is to disclose methods and systems for free energy recovery in vehicles, when a decoupling device is in a closed state.
[007] Another object of embodiments as disclosed herein is to disclose methods and systems for free energy recovery in vehicles, when a decoupling device is in a partially closed state.

BRIEF DESCRIPTION OF FIGURES
[008] Embodiments disclosed 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:
[009] FIG. 1 depicts a hybrid powertrain arrangement with free energy recovery system, according to embodiments as disclosed herein;
[0010] FIG. 2 depicts conditions under which free energy recovery system with different powertrain statuses can be activated, according to embodiments as disclosed herein;
[0011] FIGs. 3a and 3b are flow diagrams which shows conditions under which free energy recovery system can be activated, according to embodiments as disclosed herein;
[0012] FIG. 4 is a graph data which depicts the operation in free energy recovery system, according to the embodiments as disclosed herein; and
[0013] FIG. 5 is a graph showing example empirical data, according to the embodiments as disclosed herein.

DETAILED DESCRIPTION
[0014] 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.
[0015] The embodiments herein achieve methods and systems for free energy recovery in vehicles, when a decoupling device is not open. Referring now to the drawings, and more particularly to FIGS. 1 through 5, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0016] Vehicle refers to a hybrid vehicle comprising of a battery and at least one other energy source such as solar photovoltaic cells, wind energy generators, and so on. The vehicle can be connected to at least one internal and/or external load. The vehicle can be at least one of a car, truck, van, load carrying vehicle, train, boat, ship, and so on.
[0017] Embodiments herein disclose methods and systems of free energy recovery system (FERS) during vehicle slow down, for a vehicle having secondary power source (electric or hydraulic machine or Flywheel) directly mounted on primary power source (engine) when the decoupling device (between the primary power source and driveline) is not open. Embodiments herein disclose the arrangement and mechanism of free energy recovery system depending on various powertrain statuses to recover back the kinetic energy of the vehicle, which is lost in the form of drag, or brake heat for a conventional vehicle configuration. Embodiments herein will apply braking torque on the driveline when the decoupling device is in closed as well as in a partially closed state.
[0018] Embodiments herein disclose methods and systems for free energy recovery in two-powertrain status. The systems and methods disclosed herein utilizes the secondary power system to provide negative power to the driveline and converts the vehicle’s kinetic energy to other forms of energy (can be electrical energy in case of electric hybrid, rotational energy in case of flywheel based hybrid or pressurized fluid in case of hydraulic hybrid) for recharging an energy storage device.
[0019] Embodiments as disclosed herein can be activated on the basis of a driver based trigger (such as accelerator pedal release, brake pedal press, and so on), the charge level of the energy storage system, capability of the secondary power source, vehicle velocity, engine speed, and so on.
[0020] FIG. 1 depicts a hybrid powertrain arrangement with free energy recovery system. A free energy recovery system (FERS) for vehicle slow down operating mode of vehicle application is implemented on a powertrain arrangement as detailed in FIG. 1, wherein there are two power sources. The powertrain arrangement as depicted in FIG. 1 has a primary power source, which is a mechanical system of any kind producing output torque, and a secondary power source, which is a mechanical system, different from the primary power source, which produces output torque. Embodiments herein are implemented on a powertrain arrangement wherein the primary power source and the secondary power source are rigidly coupled.
[0021] Referring to FIG. 1 wherein the primary power source (PS1) 5, is a mechanical system, which produces torque output. PS1 5 may be at least one of an internal combustion engine of a spark ignition type or a compression ignition engine type. The PS1 5 is connected to a suitable flywheel damper arrangement 10, which may be a single mass flywheel or a dual mass flywheel or a flex plate or any other arrangement that stores rotational energy. The flywheel 10 can be connected to a secondary power source (PS2) 15, which is a mechanical system that produces torque output. PS2 15 may be at least one of an electric motor generator assembly or hydraulic machine or a flywheel. A controller 45 can control the PS2. The controller 45 is the master controller for hybrid powertrain of the vehicle. The PS2 15 draws power for propulsion through a device 60, which draws energy from an energy storage device 75. The energy storage device 75 can be at least one of a battery, hydraulic accumulator or a flywheel energy storage system. A sensor 70 on the energy storage device 75 communicates the potential charge capacity leftover, in the energy storage device system 75, to the controllers 40, 45, and 145. In an embodiment, the primary power source (PS1) and the secondary power source (PS2) always rotate at same relative rotational speed. In an embodiment herein, there can be a flywheel present between the primary power source (PS1) and secondary power source (PS2), wherein the flywheel can be at least one of a single mass flywheel or a dual mass flywheel.
[0022] The secondary power source 15 is further connected to a clutch assembly 55. The primary power source and the secondary power source are rigidly connected and rotate at almost speed all the time. The transmission aids in the multiplication of torque from either the primary power source (PS1) or the secondary power source (PS2) or together to the wheels.
[0023] In an embodiment herein, the vehicle cannot comprise of a clutch assembly and can comprise of an alternate means of controlling gears such as automatic transmissions, automated manual transmissions, and so on.
[0024] The controller 40 is used for controlling the operation of the primary power source (PS1) 5 which controls the fuel quantity 25 based on inputs like vehicle speed 95, engine speed 65, clutch position 200, gear engagement information 210, accelerator pedal demand 35, and so on.
[0025] The primary and the secondary power source 5 and 15, which are rigidly coupled, can be connected to the transmission unit 85 after the clutch assembly 55. The drivetrain further may further comprise of a propeller shaft 80, a differential assembly 105, wheels 90 and brake device 135.
[0026] Embodiments herein determine the decoupling status based on factors such as the speed of the primary power source (PS1), vehicle speed and the currently engaged gear, in case status shown by the decoupling sensor is not closed.
[0027] FIG. 2 depicts conditions under which free energy recovery system with different powertrain statuses can be activated. During activated FERS function, secondary power source (PS2) will provide negative torque to the powertrain to recover vehicle kinetic energy, which would have lost to vehicle drag or as brake energy.
[0028] The free energy recovery system (FERS) can be enabled based on the output from the sensors 40, 45, 65, 70, 135, 200 and 210. Controllers 40, 45, 65 and 75 shall be operational and the clutch position shall be less than a pre-defined level F. The gear engagement information shall be above a pre-defined level E. The powertrain rotational speed shall be above a pre-defined rpm (revolutions per minute) D. The vehicle speed shall be above a pre-defined speed B. The charge level available in energy storage device 75 shall be less then a pre-defined C %. The accelerator pedal position shall be less than a pre-defined level A. The brake pedal position shall be more than a pre-defined level A1. The engine quantity shall be less than a pre-defined level H. The torque capability of secondary power source (PS2) shall be above G. The status of brake controller device shall be below a pre-defined level I. The parameters A, A1, B, C, D, E, F, G, H and I can be pre-defined. An authorized person, such as a user, a service center employee, an authorized mechanic, the manufacturer, and so on, can configure the parameters.
[0029] In an embodiment herein, the controllers as disclosed herein can be discrete components. In an embodiment herein, a single dedicated controller herein can perform the functions of the controllers as disclosed. . In an embodiment herein, the functions of the controllers as disclosed herein can be performed by an ECU (Engine Controller Unit) present in the vehicle.
[0030] FIGs. 3a and 3b are flow diagrams, which shows conditions under which free energy recovery system can be activated. When the vehicle is ready for operation (301) and if vehicle speed (value(95)) is above B (302) and if charge capacity left in the energy storage device 75 (value(70)) is below C (303) and if the primary powertrain speed (value(65)) is above D (304) and if the gear engagement of powertrain (value(210)) is above E (305) and if status of brake controller (value(135)) is below I (306) and if both injection quantity (value(25)) and driver demand based on accelerator pedal, (value(35)) are below H and A respectively (307). The method involves checking further if status of the brake pedal position (value(140)) is greater than A1 (308). If value(140) is greater than A1 and the powertrain decoupling device status value(200) is below F1 (309), the secondary power source (PS2) will be engaged (310) as a generator to provide a negative torque to powertrain which will be a function of vehicle acceleration level (value(240)), primary power source speed (PS1) (value(65)), engaged gear, (value(210)), brake pedal position (value(140)), and secondary power source torque capability (value(155)). If the value(200) exceeds F1 (309), the status of the powertrain decoupling device (value(201)) will be calculated (311), based out of calculation from vehicle speed (value(95)), gear engagement (value(210)) and primary power source speed (PS1) (value(65)). If value(201) is less than F of the decoupling device (312), the secondary power source (PS2) will be engaged (313) as generator to provide a negative torque to powertrain which will be a function of vehicle acceleration level (value(240)), primary power source speed (PS1) (value(65)), engaged gear (value(210)), brake pedal position (value(140)), calculated decoupling status (value(201)) and secondary power source torque capability (value(155)). If value(140) is not greater than A1 and the value(200) is less than F1 (314), then the secondary power source (PS2) will be engaged (310) as a generator to provide a negative torque to powertrain which will be a function of vehicle acceleration level (value(240)), primary power source speed (PS1) (value(65)), engaged gear, (value(210)), brake pedal position (value(140)), and secondary power source torque capability (value(155)). If value(140) is not greater than A1 and the value(200) is not less than F1 (314), the status of the powertrain decoupling device (value(201)) will be calculated (315), based out of calculation from vehicle speed (value(95)), gear engagement (value(210)) and primary power source speed (PS1) (value(65)). If value(201) is less than F of the decoupling device (316), the secondary power source (PS2) will be engaged (313) as generator to provide a negative torque to powertrain which will be a function of vehicle acceleration level (value(240)), primary power source speed (PS1) (value(65)), engaged gear (value(210)), brake pedal position (value(140)), calculated decoupling status (value(201)) and secondary power source torque capability (value(155)). If any of the conditions are not satisfied, PS2 is not initiated as a generator (317). The various actions in method 300 may be performed in the order presented, in a different order or simultaneously. Further, in some embodiments, some actions listed in FIGs 3a and 3b may be omitted.
[0031] FIG. 4 is a graph data, which depicts the operation in free energy recovery system. The parameter 110 refers to the vehicle velocity, parameter 120 refers to the injection quantity, the parameter 130 refers to the primary power source speed, the parameter 140 refers to the accelerator pedal during vehicle drive, the parameter 200 refers to clutch position, the parameter 210 refers to gear engagement information, the parameter 190 refers to the charge level of energy storage device 75, the parameter 230 refers to brake pedal position, the parameter 220 refers to output torque of secondary power source (PS2). The region 160 depicts the region where FERS function gets activated based on the satisfied conditions in FIG. 2. In the region 160 wherein the free energy recovery system (FERS) function gets activated, the secondary power source will provide negative torque as per curve 220 thus for a duration of time under 160, the free energy recovered from kinetic energy of vehicle will charge the energy storage device 75.
[0032] When any of the conditions as provided in the embodiment of FIG. 2 are not satisfied after the function has been activated, the negative torque of the secondary power source (PS2) 220 will be reduced with a configurable slope and the FERS function will be deactivated.
[0033] FIG. 5 is a graph showing example empirical data. FIG. 5 depicts statistical data from real world driving situation where in a driver tends to prefer decoupling device in semi-pressed conditions and hence recovery of free energy is a challenge. As can be seen from FIG. 5, 300 represents the overall % time energy recovery is possible as per the condition defined in logic of FIG. 2, except considering condition of decoupling device status and 310 represents the percentage of time that the decoupling device was not in closed status and hence the free energy was not being recovered. The graph on FIG. 5 shows that overall time of 14% to 28% is being not utilized for free recovery of energy when vehicle was slowing down.
[0034] Embodiments disclosed herein can operate in any speed above idle speed for each defined gear and hence will not load idle governor.
[0035] Embodiments disclosed herein do not cause any judder or jerk during the function entry or exit (transitions).
[0036] In embodiments disclosed herein, the secondary power source is rigidly coupled to the primary power source, so during vehicle slow down operation, the inertial drag of the primary power source will also be applied to overall drivetrain for slowing down, but overall recovered energy will remain same with the help of adapting friction brake and also this will avoid the complexity of controlling decoupling mechanism and related cost of the system. In the disclosed embodiments, free energy recovery system (FERS) will apply braking torque on the driveline when decoupling device is in closed as well as in partially closed state.
[0037] Embodiments herein enable energy recovery in vehicles, based on various power statuses, during vehicle slow down which could have lost in conventional vehicle and more particularly, to a defining recuperation system for a hybrid vehicle, which provides improved efficiency and fuel economy benefits.
[0038] 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 preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the embodiments as described herein.

,CLAIMS:STATEMENT OF CLAIMS
We claim:
1. A method for recovering free energy in a vehicle when a decoupling device in the vehicle is not open, the method comprising
checking if speed of the vehicle is above a pre-defined speed limit B by at least one controller;
checking if charge capacity left in an energy storage device is below a pre-defined limit C by the at least one controller;
checking if gear engagement of powertrain in the vehicle is above a pre-defined limit E by the at least one controller;
checking if status of brake controller in the vehicle is below a pre-defined threshold I by the at least one controller;
checking if both injection quantity and driver demand based on accelerator pedal are below pre-defined thresholds H and A respectively by the at least one controller;
engaging a secondary power source as a generator to provide negative torque to the powertrain by the at least one controller, if status of brake pedal position is greater than a pre-defined threshold A1 and powertrain decoupling status is below a pre-defined threshold F1;
calculating a status of the powertrain decoupling by the at least one controller, if status of brake pedal position is greater than the pre-defined threshold A1 and powertrain decoupling status is not below the pre-defined threshold F1;
engaging a secondary power source as a generator to provide negative torque to the powertrain by the at least one controller, if status of brake pedal position is not greater than a pre-defined threshold A1 and powertrain decoupling status is below a pre-defined threshold F1;
calculating a status of the powertrain decoupling by the at least one controller, if status of brake pedal position is not greater than the pre-defined threshold A1 and powertrain decoupling status is not below the pre-defined threshold F1;
engaging the secondary power source as a generator to provide negative torque to the powertrain by the at least one controller, if status of the powertrain decoupling is below a pre-defined threshold F; and
not initiating the secondary power source as a generator by the at least one controller, if at least one of the above conditions are not satisfied.
2. The method, as claimed in claim 1, wherein the primary power source and the secondary power source rotate at same relative rotational speed.
3. The method, as claimed in claim 1, wherein the negative torque provided by the secondary power source is a function of vehicle acceleration level, speed of a primary power source present in the vehicle, currently engaged gear, brake pedal position and capability of the secondary power source.
4. The method, as claimed in claim 1, wherein the at least one controller determines the status of the powertrain decoupling from vehicle speed, gear engagement and speed of the primary power source speed.
5. A system for recovering free energy in a vehicle when a decoupling device in the vehicle is not open, the system comprising at least one controller configured
checking if speed of the vehicle is above a pre-defined speed limit B;
checking if charge capacity left in an energy storage device is below a pre-defined limit C;
checking if gear engagement of powertrain in the vehicle is above a pre-defined limit E;
checking if status of brake controller in the vehicle is below a pre-defined threshold I;
checking if both injection quantity and driver demand based on accelerator pedal are below pre-defined thresholds H and A respectively;
engaging a secondary power source as a generator to provide negative torque to the powertrain, if status of brake pedal position is greater than a pre-defined threshold A1 and powertrain decoupling status is below a pre-defined threshold F1;
calculating a status of the powertrain decoupling, if status of brake pedal position is greater than the pre-defined threshold A1 and powertrain decoupling status is not below the pre-defined threshold F1;
engaging a secondary power source as a generator to provide negative torque to the powertrain, if status of brake pedal position is not greater than a pre-defined threshold A1 and powertrain decoupling status is below a pre-defined threshold F1;
calculating a status of the powertrain decoupling, if status of brake pedal position is not greater than the pre-defined threshold A1 and powertrain decoupling status is not below the pre-defined threshold F1;
engaging the secondary power source as a generator to provide negative torque to the powertrain, if status of the powertrain decoupling is below a pre-defined threshold F; and
not initiating the secondary power source as a generator, if at least one of the above conditions are not satisfied.
6. The system, as claimed in claim 5, wherein the primary power source and the secondary power source rotate at same relative rotational speed.
7. The system, as claimed in claim 5, wherein the at least one controller is configured for determining the negative torque provided by the secondary power source a a function of vehicle acceleration level, speed of a primary power source present in the vehicle, currently engaged gear, brake pedal position and capability of the secondary power source.
8. The system, as claimed in claim 5, wherein the at least one controller is configured for determining the status of the powertrain decoupling from vehicle speed, gear engagement and speed of the primary power source speed.