초록 ▼

A distributed power generating system enables very rapid and reliable start-up of an engine used to generate back-up power, thereby substantially reducing the need for stored power. More particularly, the distributed power generating system comprises a power bus electrically coupled to commercial po

A distributed power generating system enables very rapid and reliable start-up of an engine used to generate back-up power, thereby substantially reducing the need for stored power. More particularly, the distributed power generating system comprises a power bus electrically coupled to commercial power and to a load, an engine comprising a rotatable shaft, a starter/generator operatively coupled to the shaft of the engine and electrically coupled to the power bus, and a temporary storage device electrically coupled to the power bus. The starter/generator is adapted to start the engine from a standstill condition and rapidly bring the engine to an operational speed sustainable by the engine alone. In an embodiment of the invention, the power generating system further includes a plurality of redundant fuel tanks each containing liquid fuel, such as propane, at a respective initial pressure level. A fuel delivery system operatively couples a selected one of the plurality of fuel tanks to the engine to supply fuel thereto. The fuel delivery system supplies vaporized fuel to the engine at a first reduced pressure level relative to the initial pressure level of the selected one of the plurality of fuel tanks while the starter/generator is starting the engine from the standstill condition, and supplies vaporized fuel to the engine at a second reduced pressure level lower than the first reduced pressure level when the engine reaches the operational speed. By supplying fuel to the engine at the first reduced pressure level, the fuel is delivered rapidly to the engine in order to promote fast startup from the standstill condition.

대표청구항 ▼

1. A power generating system, comprising:an internal combustion engine; a starter/generator operatively coupled to the engine, the starter/generator adapted to start the engine from a standstill condition and bring the engine to an operational speed sustainable by the engine alone whereupon said sta

1. A power generating system, comprising:an internal combustion engine; a starter/generator operatively coupled to the engine, the starter/generator adapted to start the engine from a standstill condition and bring the engine to an operational speed sustainable by the engine alone whereupon said starter/generator supplies back-up electrical power to a load; a plurality of redundant fuel tanks each containing fuel at a respective initial pressure level; and a fuel delivery system operatively coupling a selected one of said plurality of fuel tanks to said engine to supply said fuel thereto, said fuel delivery system supplying said fuel to said engine at a first reduced pressure level relative to the initial pressure level of said selected one of said plurality of fuel tanks while said starter/generator is starting said engine from said standstill condition, and supplying said fuel to said engine at a second reduced pressure level lower than said first reduced pressure level when said engine reaches said operational speed; wherein, supply of said fuel to said engine at said first reduced pressure level promotes fast start of said engine from said standstill condition. 2. The power generating system of claim 1, further comprising a manually operative tank cutoff valve coupled between each respective one of said plurality of fuel tanks and said fuel delivery system.3. The power generating system of claim 1, wherein said fuel delivery system further comprises an automatically operative main cutoff valve disposed close to said engine.4. The power generating system of claim 1, wherein said fuel delivery system further comprises an automatically operative tank cutoff valve disposed upstream from each respective one of said plurality of fuel tanks.5. The power generating system of claim 1, wherein said fuel delivery system further comprises a first regulator reducing pressure of said fuel from said respective pressure of said selected one of said plurality of fuel tanks to said first reduced pressure level.6. The power generating system of claim 5, wherein said first regulator further comprises a vaporizer adapted to change said fuel to a gaseous state.7. The power generating system of claim 5, wherein said fuel delivery system further comprises a second regulator reducing pressure of said fuel from said first reduced pressure level to said second reduced pressure level.8. The power generating system of claim 7, wherein said fuel delivery system further comprises a bypass valve coupling said first regulator directly to said engine, said bypass valve being selectively activated while said starter/generator is starting said engine from said standstill condition.9. The power generating system of claim 1, wherein said first reduced pressure level comprises a low positive pressure level.10. The power generating system of claim 9, wherein said first reduced pressure level comprises approximately 35 millibars.11. The power generating system of claim 1, wherein said second reduced pressure level comprises a low negative pressure level.12. The power generating system of claim 11, wherein said second reduced pressure level comprises approximately ?0.125 millibars.13. The power generating system of claim 1, wherein the starter/generator has a short time torque capability higher than a rated torque of said engine.14. The power generating system of claim 1, wherein said engine reaches the operational speed in less than one second.15. The power generating system of claim 1, wherein said engine reaches the operational speed in less than 0.2 second.16. The power generating system of claim 1, wherein said engine further comprises a reciprocating internal combustion engine.17. The power generating system of claim 1, wherein said fuel further comprises propane.18. The power generating system of claim 1, further comprising a secondary fuel source coupled to said fuel delivery system for supply of a secondary fuel to said engine.19. The power generating system of claim 18, wherein said secondary fuel comprises compressed natural gas.20. The power generating system of claim 18, wherein said secondary fuel source comprises a commercial compressed natural gas pipeline.21. The power generating system of claim 18, wherein said fuel delivery system further comprises main fuel line providing a first flow rate to said engine that corresponds to energy content of said secondary fuel and a second flow rate to said engine that corresponds to energy content of said fuel from said redundant fuel tanks.22. The power generating system of claim 1, wherein said plurality of redundant fuel tanks each comprises a weight sensor adapted to determine weight of a corresponding fuel tank.23. The power generating system of claim 1, wherein said plurality of redundant fuel tanks each comprises a pressure sensor adapted to determine said pressure level of a corresponding fuel tank.24. A method for operating a power generating system, comprising:selecting one of a plurality of fuel tanks for delivery of fuel to an engine; upon receipt of an indication to start the engine from a standstill condition, opening a main valve separating said selected fuel tank from said engine, supplying said fuel from said selected fuel tank to said engine at a first pressure level, starting said engine using a starter/generator operatively coupled to the engine, bringing the engine to an operational speed sustainable by the engine alone, and then supplying said fuel to said engine at a second pressure level lower than said first pressure level when said engine reaches said operational speed whereupon said starter/generator supplies back-up electrical power to a load; and upon receipt of an indication to stop the engine, closing said main valve. 25. The method of claim 24, wherein said step of rapidly bringing said engine to an operational speed further comprises bringing said engine to said operational speed in less than one second.26. The method of claim 24, wherein simultaneous with said step of opening said main valve, opening a tank cutoff valve coupled between said selected fuel tank and said engine.27. The method of claim 26, wherein following opening of said tank cutoff valve and said main valve, vaporizing said fuel to a gaseous state.28. The method of claim 24, wherein supplying said fuel from said selected fuel tank to said engine at said first pressure level further comprises reducing pressure of said fuel from an initial pressure level of said selected fuel tank to said first pressure level.29. The method of claim 24, wherein supplying said fuel to said engine at said second pressure level further comprises reducing pressure of said fuel from said first pressure level to said second pressure level.30. The method of claim 24, wherein supplying said fuel to said engine at said second pressure level further comprises opening a bypass valve.31. The method of claim 24, wherein supplying said fuel from said selected fuel tank to said engine at said first pressure level further comprises supplying said fuel at a low positive pressure level.32. The method of claim 24, wherein supplying said fuel to said engine at said second pressure level further comprises supplying said fuel at a low negative pressure level.33. The method of claim 24, further comprising supplying a secondary fuel to said engine.34. The method of claim 33, further comprising controlling a flow rate of said secondary fuel to said engine that accommodates for energy content of said secondary fuel.35. The method of claim 24, wherein selecting one of a plurality of fuel tanks further comprises determining weight of each one of said plurality of fuel tanks and selecting one having lowest weight.36. The method of claim 24, wherein selecting one of a plurality of fuel tanks further comprises determining said initial pressure level of each one of said plurality of fuel tanks.