Claims:STATEMENT OF CLAIMS
We claim:
1. A system (100) for managing energy in a vehicle, the system (100) comprising a converter (101), an energy storage device (102), a belt starter generator (BSG) (103), at least one battery (104) and at least one load (106), the BSG (103) configured for
taking power from at least one of the battery (104); and the energy storage device (102) for cranking an engine present in the vehicle;
drawing power from the energy storage device (102) for providing power to the engine for re-cranking;
providing power to the at least one load (106) through the converter (101) in a normal generation mode, if current drawn by the at least one load (106) is lesser than a current limit of the converter (101);
providing power to the at least one load (106) from the battery (104) in a normal generation mode, if current drawn by the at least one load (106) is not lesser than the current limit of the converter (101); and
using power stored in the energy storage device (102) to assist the engine, when the vehicle is accelerating.

2. The system, as claimed in claim 1, wherein the energy storage device (102) is at least one of an ultra-capacitor, and a lithium ion battery.
3. The system, as claimed in claim 1, wherein the system further comprises of a bypass circuit (107) and a pre-charging circuit (108).

4. The system, as claimed in claim 3, wherein the BSG (103) is configured to be connected directly to the at least one load using the bypass circuit (107), if there is a failure in the converter (101).

5. The system, as claimed in claim 3, wherein the energy storage device (102) is configured to be charged from the battery using the pre-charging circuit (108).

6. The system, as claimed in claim 3, wherein the BSG (103) is configured to take power from at least one of the battery (104); and the energy storage device (102) using a bypass circuit (107).

7. The system, as claimed in claim 3, wherein the BSG (103) is configured for drawing power from the energy storage device (102) for providing power to the engine for re-cranking, while the bypass circuit remains open.

8. The system, as claimed in claim 1, wherein the BSG (103) can be configured to perform torque assist and generation based on control mode request.
9. The system, as claimed in claim 1, wherein the BSG (103) can be configured to operate in a maximum efficiency point at a higher voltage during recuperation event.

10. The system, as claimed in claim 1, wherein the BSG (103) can be configured to work in a variable voltage mode during recuperation.

11. The system, as claimed in claim 1, wherein the energy storage device (102) is configured to be in a low state, during the normal generation mode.

12. The system, as claimed in claim 1, wherein the energy storage device (102) is configured to deliver power to the at least one load (106) through the converter (101), if SOC (State of Charge) of the battery (104) is below a minimum allowable threshold.

13. The system, as claimed in claim 1, wherein the system (100) is configured to discharge the battery (104) by putting the converter (101) in standby mode and opening the bypass circuit (107), if the SOC of the battery (104) is not below the minimum allowable threshold.

14. The system, as claimed in claim 1, wherein the converter (101) is configured to discharge the energy storage device (102) to a pre-defined lower level on detecting at least one emergency condition.
, Description:TECHNICAL FIELD
[001] Embodiments disclosed herein relate to energy systems for vehicles, and more particularly to dual energy storage systems for vehicles.

BACKGROUND
[002] Conventional vehicles with ICE (Internal Combustion Engine) have efficiency zones, which are characterized by vehicle operating modes. There are scenarios such as startup during normal conditions and cold temperatures, which increase vehicular fuel consumption and emission. Also, as electrical loads increase (due to increasing use of electrical accessories), the load on the engine to provide power to these loads would increase. This can lead to engine loading caused by inefficient power transitions.

OBJECTS
[003] The principal object of the embodiments disclosed herein is to disclose a dual energy storage system for vehicle, wherein the system comprises an energy storage device, a belt-starter generator, and a DC/DC converter.
[004] Another object of the embodiments disclosed herein is to disclose a dual energy storage system for vehicle, wherein the system utilizes free energy available during braking.
[005] Another object of the embodiments disclosed herein is to disclose a dual energy storage system for vehicle, wherein the system reduces engine loading using the energy storage device.

BRIEF DESCRIPTION OF FIGURES
[006] This invention is 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:
[007] FIGs. 1a, 1b, 1c and 1d depict systems for managing the energy in a vehicle, according to embodiments as disclosed herein;
[008] FIG. 2 depicts the bypass circuit, according to embodiments as disclosed herein; and
[009] FIG. 3 depicts the pre-charging circuit, according to embodiments as disclosed herein.

DETAILED DESCRIPTION
[0010] 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.
[0011] The embodiments herein disclose a dual energy storage system for vehicle, wherein the system comprises an energy storage device, a belt-starter generator, and a DC/DC converter. Referring now to the drawings, and more particularly to FIGs. 1 through 3, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0012] FIGs. 1a, 1b, 1c and 1d depict systems for managing the energy in a vehicle. The system 100, as depicted, comprises of a DC-DC converter 101, an energy storage device 102, a belt starter generator (BSG) 103, at least one battery 104, a starter 105, and a plurality of loads 106. The energy storage device 102 can be any device, which can swing from a low voltage to a higher voltage. Examples of the energy storage device 102 can be, but not limited to, lithium ion batteries, ultra-capacitors, or any other electrochemical energy storage device. The energy storage device 102 can be used to store recuperation energy very quickly. The energy stored in the energy storage device 102 can be used during acceleration event to support the loads hereby not requiring the engine to supply power to the loads, thereby improving the performance of the vehicle during dynamic conditions. The energy storage device 102 can be combined with the converter 101 at a low voltage level to provide stable power to vehicle loads.
[0013] The converter 101 can convert variable input voltage range to a constant required set point output range. In an example, the converter 101 can convert input voltage in the range of 11V – 35V to a constant required set point output range of 13.2V – 14.2V. The converter 101 can also perform functions such as bypassing, pre-charging, active discharging, and so on. The converter 101 can ensure that the voltage provided to the loads 106 is stable, during scenarios such as idle stop and go, recuperation, higher/low voltage generation, active boosting, passive boosting, and so on. The converter 101 can be configured to help enable cycling of the battery 104. In an embodiment herein, the converter 101 can be a buck/boost converter.
[0014] The BSG 103 can perform torque assist and generation based on control mode request. The BSG 103 can operate in maximum efficiency point at a higher voltage during recuperation brake energy recovery time. In an example herein, the BSG 103 can operate at 5kW at 35V, 142 A. This can reduce the charging current flowing through the energy storage device 102. Considering the example herein, this can reduce the charging current by 2.5 times. The BSG 103 can work in a variable voltage mode (wherein voltage can be varied across a pre-defined range) during recuperation. In an example herein, the pre-defined range can be 12V to 35V.
[0015] The BSG 103 can be used for cranking the engine by taking power from at least one of the battery 104 (through a bypass circuit 107 comprising of a switch 201 (as depicted in FIG. 2)) or the energy storage device 102 (depending on energy/voltage available in the energy storage device 102). During engine cranking phase, the BSG 103 can draw power directly from the battery 104 for functions such as engine cranking through the bypass circuit 107. During Start/Stop condition, the BSG 103 can draw power from the energy storage device 102 for smooth fast engine re-crank, while the bypass circuit 107 remains open.
[0016] During normal generation mode of the BSG 103, the energy storage device 102 will not be charged. The energy storage device 102 will be discharged to a low state (for example, to 11V) & kept in that state. If the current drawn by the loads 106 is lesser than a maximum converter current limit of the converter 101, the BSG 102 will provide power to the loads 106 through the converter 101. If the current drawn by the loads 106 is not lesser than the maximum converter current limit of the converter 101, the switch 201 will be turned on and the BSG 103 is connected directly to the loads 106 and the battery 104 will provide the current to the loads 106. The energy storage device 102 can be kept at the low state, such that the energy storage device 102 can accept the energy coming from the next recuperation event (also referred to herein as a braking event or a deceleration event).
[0017] During vehicle acceleration, energy stored in the energy storage device 102 can be used to assist the engine using the BSG 103. Here, the BSG 103 can act as a motor. The energy storage device 102 can deliver power to the loads 106 through the converter 101, if the SOC (State of Charge) of the battery 104 is below a minimum allowable threshold. If the SOC of the battery 104 is not below the minimum allowable threshold, the battery 104 can be discharged by providing power to the loads 106, such that the SOC of the battery 104 reaches the minimum allowable threshold. This leads to the battery being charged to full voltage during the next recuperation cycle. This can result in an improvement in the life of the battery 104. The converter 101 will be in standby mode and the bypass circuit 107 is open so that the battery 104 can be discharged.
[0018] During idle stop and go conditions, the engine automatically turned off, when the vehicle stops for at least a pre-defined period of time. At the time of restarting the vehicle, the BSG 103 can draw power from the energy storage device 102 to re-crank the engine. This can result in better NVH (Noise, Vibration and Harshness), as compared to using the starter motor.
[0019] The bypass circuit 107 can be used to bypass the converter 101 and connect the BSG 103 directly to the loads 106, if there is a failure in the controller 101.
[0020] In an embodiment herein, the converter 101 can actively discharge the energy storage device 102 to a pre-defined lower level, to avoid any hazard relevant to energy stored in the energy storage device 102 during any emergency condition like crash, short circuit and so on.
[0021] Whenever the voltage of the energy storage device 102 goes below a lower level, the energy storage device 102 can be charged from the battery 104 using a pre-charging circuit 108 present in the converter 101. The pre-charging circuit 108 can comprise of a relay 301 and a resistor 302 (as depicted in FIG. 3). In an embodiment herein, the resistor 302 can be a fixed resistor. This enables the BSG 103 to be bought back to normal function (minimum BSG excitation voltage).
[0022] In an embodiment herein, the bypass circuit 107 and the pre-charging circuit 108 can be present in the converter 101 (as depicted in Fig. 1a). In an embodiment herein, the bypass circuit 107 can be present inside the converter 101, while the pre-charging circuit 108 can be present outside the converter 101 (as depicted in Fig. 1b). In an embodiment herein, the bypass circuit 107 and the pre-charging circuit 108 can be present outside the converter 101 (as depicted in Fig. 1c). In an embodiment herein, the pre-charging circuit 108 can be present inside the converter 101, while the bypass circuit 107 can be present outside the converter 101 (as depicted in Fig. 1d).
[0023] Embodiments herein disclose methods and systems for improving the fuel economy of the vehicle by recovering more free brake energy (recuperation) and supplying it to the loads via the converter during engine acceleration, cruising condition, and so on, by cutting off generation load of the BSG 103 on an engine of the vehicle.
[0024] Embodiments disclosed herein can accommodate and reduce engine loading by enabling efficient power transitions. Embodiments disclosed herein can isolate generation and comfort starting. In addition, embodiments disclosed herein provide a provision for redundant safety needs, which ensures that power cut-off does not happen.
[0025] Embodiments disclosed herein can help increase fuel efficiency and at the same time also down size the battery 104. Embodiments disclosed herein can enhance the life of the battery 104 by cycling the battery 104.
[0026] 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.