Patent Application
20160108790
The present disclosure relates to a waste heat recovery system associated with an engine system, and more particularly to a waste heat recovery system for generating power from exhaust gases exiting the engine system.
In an engine, thermal energy generated by combustion of air and fuel mixture is converted into mechanical energy. During this energy conversion process, a portion of the thermal energy is converted to useful work and remaining portion is wasted in the form of heat into atmosphere via various engine components. Thus, an effective utilization of the thermal energy generated by the engine is challenged.
U.S. Patent Publication number 2010/0186399, hereinafter referred to as the '399 publication, describes a thermoelectric facility contains a thermoelectric generator. The thermoelectric generator is thermally connected on a first side to a heat source and on a second side to a heat sink. The thermoelectric facility also has a structure for limiting the temperature on the thermoelectric generator. The structure includes a first compartment, filled with a first working medium that can melt, which compartment is connected across a large surface thereof to the heat source or to a second compartment that is filled with an evaporable second working medium. The second compartment is connected to the thermoelectric generator on its side facing away from the first compartment. The working media have a predetermined melting point or boiling point in order to prevent permanent damages to the thermoelectric generator. The thermoelectric facility is especially useful for motor vehicles that are operated by an internal combustion engine. However, the thermoelectric facility described in the '399 publication includes multiple components that makes the facility complex in operation and also increases an overall cost associated with energy generation.
In one aspect of the present disclosure, a waste heat recovery system of an engine is provided. The engine includes an aftertreatment system. The waste heat recovery system includes an inlet member adapted to introduce exhaust gases in the aftertreatment system. The waste heat recovery system also includes a Selective Catalytic Reduction (SCR) module in fluid communication and attached downstream to the inlet member. The waste heat recovery system further includes an outlet member adapted to receive the exhaust gases from the SCR module and attached downstream of the SCR module. The outlet member includes a first surface defining a passage for flow of the exhaust gases therethrough. The outlet member also includes a second surface coupled with a power generation module. The power generation module includes a plurality of power generation units. The plurality of power generation units includes a first lead and a second lead. The plurality of power generating units is adapted to generate electric power based on a temperature gradient between the first lead and the second lead. Also, at least one of the first lead and the second lead is exposed to the exhaust gases flowing through the passage. Further, an electric load is coupled with the plurality of power generating units. The electric load is adapted to utilize the power generated by the plurality of power generating units.
Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.
Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts.
The engine system 10 also includes an aftertreatment system 16 for treating exhaust gases exiting the engine 12. More particularly, the aftertreatment system 16 is provided to trap or treat NOx, unburned hydrocarbons, particulate matter, combination thereof, or other combustion products present in the exhaust gases. In particular, the aftertreatment system 16 reduces NOx to relatively less toxic or less polluting end products. An exhaust conduit 14 provides fluid communication between an exhaust manifold (not shown) of the engine 12 and the aftertreatment system 16. The exhaust gases exiting the engine 12 are introduced in the aftertreatment system 16 by the exhaust conduit 14.
The aftertreatment system 16 includes a mixing tube 28. The mixing tube 28 is disposed between the first wall 32 and the second wall 34 in such a manner that the mixing tube 28 is in alignment with the inlet portion 24 and the inlet member 36. The mixing tube 28 includes a reductant injector (not shown). The reductant injector introduces a reductant in the exhaust gases entering the aftertreatment system 16. The reductant may include, but is not limited to, ammonia, urea or any other reductant know in the art. The urea containing solution may include, but is not limited to, an automotive grade urea, such as, diesel exhaust fluid. Further, the mixing tube 28 includes mixing elements (not shown) that allow uniform mixing of the exhaust gases with the reductant. In one example, the aftertreatment system 16 may also include a Diesel Oxidation Catalyst (DOC), a Diesel Particulate Filter (DPF), or a combination thereof, without limiting the scope of the present disclosure. The DOC/DPF may be positioned upstream of the mixing tube 28 along an exhaust gas flow direction “F”.
The aftertreatment system 16 includes a Selective Catalytic Reduction (SCR) Module 30. The SCR module 30 operates to treat the exhaust gases in the presence of a catalyst, which is provided after degradation of the reductant injected into the exhaust gases. The SCR module 30 is positioned downstream of the inlet member 36, along the exhaust gas flow direction “F”. The SCR module 30 is disposed between the first wall 32 and the second wall 34 of the housing member 22. The mixing tube 28 and the SCR module 30 have a flow-through configuration. The flow-through configuration allows the exhaust gases exiting the mixing tube 28 to flow through the SCR module 30. The SCR module 30 includes one or more SCR catalysts 31. The SCR catalysts 31 may include, but not limited to, oxides of base metals, such as vanadium, molybdenum, and tungsten.
The housing member 22 also includes an outlet portion 26. The outlet portion 26 is coupled to the first wall 32. The SCR module 30 is in fluid communication with the outlet portion 26. Further, an outlet member 38 is coupled to the outlet portion 26. The outlet member 38 receives the treated exhaust gases from the outlet portion 26. The outlet member 38 is disposed downstream of the SCR module 30, with respect to the exhaust gas flow direction “F”.
The aftertreatment system 16 includes a waste heat recovery system 18. The waste heat recovery system 18 generates electric power from thermal energy dissipated by the treated exhaust gases flowing through the outlet member 38. The waste heat recovery system 18 includes a power generation module 54. The power generation module 54 is coupled to the second surface 50 of the outlet member 38.
The power generation module 54 includes a number of power generating units 56. Each of the power generating units 56 includes a first lead 58 (shown in
In one example, the first lead 58 of the power generating units 56 is coupled to the second surface 50 via an adhesive layer 62 (shown in
During an operation of the engine 12, the treated exhaust gases flow through the passage 52 of the outlet member 38. The treated exhaust gases dissipate heat energy to the first surface 48 by a convection mode of heat transfer, thereby increasing a temperature of the first surface 48. The first surface 48 in turn dissipates heat energy to the second surface 50 of the outlet member 38 by a conduction mode of heat transfer, thereby increasing a temperature of the second surface 50.
Further, heat energy is transferred from the second surface 50 to the first lead 58 of the power generating units 56 through the adhesive layer 62, thereby increasing a temperature of the first lead 58. Also, the second lead 60 of the power generating units 56 is exposed to the ambient temperature that is lesser than the temperature of the first lead 58. Due to temperature difference between the first lead 58 and the second lead 60, the power generating units 56 yields electric power. In particular, each of the power generating units 56 generates electric power due to the temperature gradient between the first lead 58 and the second lead 60. The electric power generated by the power generating units 56 is transferred to an electric load 68 (shown in
The waste heat recovery system 18 enables the engine system 10 to generate electric power using the thermal energy of the treated exhaust gases that would otherwise be released into the atmosphere as waste gases. In particular, the waste heat recovery system 18 converts the thermal energy dissipated by the treated exhaust gases into electric power. The electric power can be utilized for operating a lighting system, a motor, a braking system of a machine in which the engine 12 is used, and/or any other electrical component associated with the engine 12.
The waste heat recovery system 18 eliminates the use of an electric generator that generates electrical power by using mechanical power produced from the engine 12, thereby reducing fuel consumption.
In one example, the electric power generated by the waste heat recovery system 18 can be utilized to increase power output of the engine 12 in addition to mechanical power received from a crankshaft of the engine 12. The waste heat recovery system 18 can be employed at the inlet portion 24 or the outlet portion 26 of the aftertreatment system 16. The waste heat recovery system 18 can be easily retrofitted to an existing engine system 10. The present disclosure offers the waste heat recovery system 18 that is simpler, effective, easy to use, economical, and time saving.
The electric power stored in the electrical storage is used by an inverter 70 to convert DC electric power generated by the waste heat recovery system 18 to AC electric power. Further, the inverter 70 supplies the electric power to an electric motor 72 of the engine system 10. In another example, the inverter 70 may supply the electric power to any other component of the engine system 10 or a machine equipped with the engine system 10. Although, the waste heat recovery system 18 is described with reference to the aftertreatment system 16, it may be contemplated that the waste heat recovery system 18 may be coupled to any other component of the engine system 10 that radiates thermal energy including, but not limited to, a radiator, a cylinder block, an exhaust manifold, an oil cooler, and the like.
While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed remote operating station without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.
