Claims:STATEMENT OF CLAIMS
We claim:

1. A system (100) for recovering waste heat in a vehicle, comprising a thermo electric generator (TEG) (101) connected to a exhaust pipe (102) in the vehicle and a Heating, Ventilation and Air Conditioning (HVAC) system (103), wherein the TEG (101) is configured to generate power from a temperature gradient across a plurality of semiconductor pellets (200) present in the TEG (101), wherein the temperature gradient is caused by exhaust gases from the exhaust pipe (102) and refrigerant coolant from the HVAC system (103).

2. The system, as claimed in claim 1, wherein the TEG (101) is connected behind the catalytic converter (109).

3. The system, as claimed in claim 1, wherein the system further comprises of a DC/DC converter (Direct Current/Direct Current converter) (106) configured for
stabilizing power generated by the TEG (101); and
supplying the power to at least one of a battery (104) and at least one load (105).

4. The system, as claimed in claim 3, wherein the DC/DC converter (106) is configured to stabilize power by adjusting its duty ratio.
, Description:TECHNICAL FIELD
[001] Embodiments herein relate to energy systems in vehicles, and more particularly to recovery of waste heat energy from exhaust gases in vehicles.

BACKGROUND
[002] The main problem of fuel energy transformation is that only part of the energy supplied by the fuel in an automobile is converted into power output. Loss of energy can occur due to mechanical and efficiency losses and through exhaust gas, cooling water, lubrication oil, and so on. For instance, in gasoline and diesel engines, about 30% of the primary fuel energy is discharged as waste heat in the exhaust gases.
[003] Current solutions for recovery of waste heat energy from exhaust gases in vehicles utilize a cooling loop (fluid medium which is active, such as engine coolant) from the engine along with a low temperature loop in order to generate the thermal gradient. A dedicated controller is also required to control the flow of the fluid medium.

OBJECTS
[004] The principal object of embodiments herein is to disclose methods and systems for waste heat recovery from an engine in a vehicle using a thermo-electric generator (TEG) in the exhaust stream, wherein a temperature gradient is developed across the TEG using exhaust gases and refrigerant fluid (from the Heating, Ventilation and Air Conditioning (HVAC) system).
[005] Another object of the embodiments herein is to disclose methods and systems for generating power from exhaust gases from an engine in a vehicle using a thermo-electric generator (TEG) in the exhaust stream, wherein a temperature gradient is developed across the TEG using exhaust gases and refrigerant fluid (from the Heating, Ventilation and Air Conditioning (HVAC) system).

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] FIG. 1 depicts a system for recovering waste heat from an engine in a vehicle using the TEG and generating electricity from the recovered waste heat, according to embodiments as disclosed herein; and
[008] FIG. 2 depicts an example of a semiconductor pellet, according to embodiments as disclosed herein.

DETAILED DESCRIPTION
[009] 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.
[0010] The embodiments herein disclose methods and systems for waste heat recovery from an engine in a vehicle using a thermo-electric generator (TEG) in the exhaust stream, wherein a temperature gradient is developed across the TEG using exhaust gases and refrigerant fluid (from the Heating, Ventilation and Air Conditioning (HVAC) system). Referring now to the drawings, and more particularly to FIGS. 1 through 2, where similar reference characters denote corresponding features consistently throughout the figures, there are shown preferred embodiments.
[0011] FIG. 1 depicts a system for recovering waste heat from an engine in a vehicle using the TEG and generating electricity from the recovered waste heat. The system 100, as depicted, comprises of a TEG 101. The TEG 101 can comprise of a plurality of semiconductor pellets connected in a series and parallel combination. In an embodiment herein, the semiconductor pellet can be based on bismuth telluride alloys.
[0012] The TEG 101 can be connected to the exhaust pipe 102 of the vehicle and the HVAC system 103. The TEG device 101 can be connected just behind the catalytic converter 109. The output of the TEG 101 can be connected to a battery present in the vehicle 104 and at least one load 105 (wherein the at least one load 105 can be provided power from at least one of the battery 104 or the TEG 101 directly), through a DC/DC converter (Direct Current/Direct Current converter) 106, a rectifier 107 and an alternator 108.
[0013] The DC/DC converter 106 can be connected to vehicle systems such that the DC/DC converter 106 can monitor parameters such as vehicle speed, engine speed, and so on. The DC/DC converter 106 can stabilize the power generated by the TEG 101 by adjusting its duty ratio to meet the constant output power requirements for available input power from the TEG 101, based on the monitored parameters.
[0014] FIG. 2 depicts an example of a semiconductor pellet. The semiconductor pellet 200, as depicted, comprises of a hot side heat exchanger 201, a cold side heat exchanger 202, insulators 203, conductors 204, metal contacts 205, N and P semiconductor elements 206, and a thermal shunt path 207. The hot side heat exchanger 201 can be in contact with the exhaust gases and the cold side heat exchanger 202 can be in contact with the refrigerant coolant. The temperature gradient across the semiconductor pellet 200 can generate electricity. The greater the temperature gradient between the hot side heat exchanger 201 and the cold side heat exchanger 202, the greater the amount of electricity generated. For example, the hot side heat exchanger 201 and the cold side heat exchanger 202 can be at 4000C and 200C respectively.
[0015] If approximately 9% of the exhaust heat and refrigerant heat could be converted into electrical power, more or less the same quantity of driving energy that demands the production of electrical power would be released and then, it would be possible to reduce the fuel consumption around 10% ~ 14% and a corresponding improvement in emission of vehicle.
[0016] Embodiments disclosed herein minimize the heat transfer surface required in the TEG 101 because the thermal flow required through the modules is lower. This decreases the pressure drop across the TEG 101 and results in a lower back pressure on the engine, hereby reducing the occurrence of back pressure. Embodiments herein use the exhaust gases directly, without using any fluid to transmit the heat from the exhaust to the TEG 101. This ensures that no intermediate energy transfer is required, hereby reducing wastage. Embodiments herein disclosed do not need a dedicated controller, which will be used to control flow of working fluid using pump and valve inside/outside the TEG. This minimizes the cost and packaging requirements. Adaptive load control, as performed by the DC/DC converter 106 can optimize fuel efficiency.
[0017] 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.