Patent Application
20080041046
The sole FIGURE is a schematic diagram of a vehicle waste heat recovery system embodying the invention.
The vehicle waste heat recovery system 10 includes a heat collecting circuit 12 and a power generating circuit 14. Heat collecting circuit 12 includes an engine driven variable speed first pump 16 which circulates a first working fluid, such as glycol/water, primarily through the conventional engine cooling circuit 18. A check valve 20 assures one-way flow of the working fluid. A variable speed second pump 22 which circulates the first working fluid through a plurality of heat generating components, including a charge air cooler 24, an air conditioner condenser 26, a fuel cooler 28, an oil cooler 30 (such as a transmission oil cooler), and heat generating electronics components 32. Valve 34 allows the selective opening or closing of flow of working fluid through charge air cooler 24. Valve 36 allows the selective opening or closing of flow of working fluid through air conditioner condenser 26. Valve 38 allows the selective opening or closing of flow of working fluid through fuel cooler 28, oil cooler 30 and the electronics components 32. Valve 40 allows the selective opening or closing of communication between the engine 18 and the other heat generating components 24-32.
Line 42 communicates heated first working fluid to a heat transfer unit 44 which transfers heat from circuit 12 to circuit 14. Line 45 communicates first working fluid from heat transfer unit 44 to second pump 22. Line 46 communicates heated first working fluid from valves 34-38 to valve 40 and the engine 18. Line 48 provides two-way communication between an accumulator 50 and line 46. A pressure control valve 52 and line 54 permits one-way communication from line 48 to line 42. A pressure control valve 56 and line 58 permits one-way communication from accumulator 60 to line 48.
Power generating circuit 14 preferably circulates a second working fluid, such as ammonia/water, at a higher pressure than the glycol/water pressure in heat collection circuit 12. Circuit 14 includes a variable speed pump 70 which receives the second working fluid from a holding/de-aeration tank 72. An accumulator 73 is connected to tank 72 for the purpose of maintaining pressure in the system.
Pump 70 pumps the second working fluid to the heat transfer unit 44 via line 74 and to a recuperator unit 76 via line 78. Line 80 communicates heated second working fluid to an exhaust gas cooler 82 which operates to super-heat the second working fluid. Line 84 communicates super-heated second working fluid to a separator unit 86. Separator unit 86 operates to separate any liquid from the vapor prior to entering the turbine 92. Recuperator unit 76 transfers heat from the hot liquid leaving the separator unit 86 to the cooled liquid starting the next cycle.
Line 88 communicates super-heated second working fluid via valve 90 from separator unit 86 to a turbine 92. Turbine drives an electrical generator 94 which can supply useful electrical power to any desired electrical powered device (not shown) on or off the vehicle, such as on an implement (not shown) coupled to the vehicle or an electrical powered tool or machine (not shown).
Lines 96 communicates working fluid from turbine 92 to an outlet of pump 70. Line 98 communicates working fluid from line 96 to an air cooled condenser 100. Line 102 communicates condensed working fluid from condenser 100 to tank 72.
Line 104 and valve 106 communicate working fluid from separator 86 to recuperator 76. Line 108 communicates working fluid from recuperator 76 to condenser 100 via line 98.
As a result, heat from a plurality of heat generator components, which might otherwise be wasted, is used to generate useful electrical power. Circuit 14 converts the waste heat to electricity by using an additional power generation cycle based on a modified Rankine cycle, known as a Kalina Cycle. The super-heating by the engine exhaust ensures maximum temperature change in the ammonia/water solution, and hence, maximum work output from the system.
While the present invention has been described in conjunction with a specific embodiment, it is understood that many alternatives, modifications and variations will be apparent to those skilled in the art in light of the foregoing description. Accordingly, this invention is intended to embrace all such alternatives, modifications and variations which fall within the spirit and scope of the appended claims.
