# US 6,718,751 B2 · Engine having external combustion chamber > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,718,751 B2 - Document ID: US6718751B2 - Status: Granted - Kind: B2 - Application number: 10/282,010 - Filed: 2002-10-29 - Published: 2003-04-03 - Granted: 2004-04-13 - Earliest claimed: 1999-10-08 - Assignees: Jeffrey S. Melcher - Inventors: James J. Mehail - Web page: https://patentgrep.com/patent/US6718751B2 ## CPC - F02G 3/02: with reciprocating-piston engines - F02G: HOT GAS OR COMBUSTION-PRODUCT POSITIVE-DISPLACEMENT ENGINE PLANTS (steam engine plants, special vapour plants, plants operating on either hot gas or combustion-product gases together with other fluid F01K; gas-turbine plants F02C; jet-propulsion plants F02K); USE OF WASTE HEAT OF COMBUSTION ENGINES; NOT OTHERWISE PROVIDED FOR ## Abstract Provided is an engine having positive displacement chambers containing pistons and an external combustion chamber which utilizes the compression energy in compressed natural gas from a high pressure main line and compressed air in combination with the energy released during combustion of the fuel to drive the pistons. Energy expended compressing the natural gas and air are recovered. Also provided is an electrical generator driven by the engine. ## Claims ### Claim 1 An engine that utilizes the compression energy of pressurized natural gas from a high pressure natural gas main line comprising: at least one positive displacement chamber; a reciprocating piston disposed in said at least one positive displacement chamber; an external combustion chamber in communication with the positive displacement chamber for containing a mixture of compressed gas; an ignitor in the combustion chamber constructed and arranged to ignite a fuel in the combustion chamber; at least one valve constructed and arranged to control the flow of the compressed gas from the combustion chamber into the positive displacement chamber; at least one exhaust valve constructed and arranged to control the flow of expanded gas from the positive displacement chamber; a high pressure main connector for connecting a high pressure natural gas main line to the combustion chamber; a high pressure main valve in communication with the high pressure main connector and combustion chamber for controlling the flow of natural gas from the high pressure natural gas main line to the combustion chamber; a high-pressure air vessel in communication with the combustion chamber; at least one valve for controlling the flow of pressurized air from the high-pressure air vessel to the combustion chamber; and at least one external valve constructed and arranged to fill the high-pressure air vessel with compressed air from an external pressurized air source. ### Claim 2 (depends on 1) An engine according to claim 1, further comprising a high-pressure fuel vessel in communication with the high pressure main connector and the combustion chamber, such that when the high pressure main connector is connected to a high pressure main natural gas can flow into the high-pressure fuel vessel and then through the high pressure main valve to the to the combustion chamber. ### Claim 3 (depends on 2) A engine according to claim 2, further comprising an overpressure valve connected to said high-pressure fuel vessel to prevent overpressurization. ### Claim 4 (depends on 1) An engine according to claim 1, further comprising at least two positive displacement chambers. ### Claim 5 (depends on 1) An engine according to claim 1, further comprising an intake manifold. ### Claim 6 (depends on 5) An engine according to claim 5, further comprising a throttle valve for controlling the amount of compressed gas from the combustion chamber to the intake manifold. ### Claim 7 (depends on 1) An engine according to claim 1, further comprising at least one check valve and at least one pressure regulator for controlling the flow of compressed air from the high-pressure air vessel to the combustion chamber. ### Claim 8 (depends on 2) An engine according to claim 2, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 1000 pounds per square inch. ### Claim 9 (depends on 2) An engine according to claim 2, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 2000 pounds per square inch. ### Claim 10 (depends on 2) An engine according to claim 2, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 3000 pounds per square inch. ### Claim 11 (depends on 2) An engine according to claim 2, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 3500 pounds per square inch. ### Claim 12 (depends on 1) An engine according to claim 1, further comprising a safety valve connected to the combustion chamber for allowing excess pressure to be vented from the combustion chamber. ### Claim 13 A fast response time electrical generator that utilizes the compression energy in compressed natural gas from a high pressure natural gas main line comprising: a generator having an electric output connector; and an engine connected to the generator, wherein the engine comprises; at least one positive displacement chamber; a reciprocating piston disposed in said at least one positive displacement chamber; an external combustion chamber in communication with the positive displacement chamber for containing a mixture of compressed gas; an ignitor in the combustion chamber constructed and arranged to ignite a fuel in the combustion chamber; at least one valve constructed and arranged to control the flow of the compressed gas from the combustion chamber into the positive displacement chamber; at least one exhaust valve constructed and arranged to control the flow of expanded gas from the positive displacement chamber; a high pressure main connector for connecting a high pressure natural gas main line to the combustion chamber; a high pressure main valve in communication with the high pressure main connector and combustion chamber for controlling the flow of natural gas from the high pressure natural gas main line to the combustion chamber; a high-pressure air vessel in communication with the combustion chamber; at least one valve for controlling the flow of pressurized air from the high-pressure air vessel to the combustion chamber; and at least one external valve constructed and arranged to fill the high-pressure air vessel with compressed air from an external pressurized air source. ### Claim 14 (depends on 13) An electrical generator according to claim 13, further comprising a high-pressure fuel vessel in communication with the high pressure main connector and the combustion chamber, such that when the high pressure main connector is connected to a high pressure main natural gas can flow into the high-pressure fuel vessel and then through the high pressure main valve to the to the combustion chamber. ### Claim 15 (depends on 14) An electrical generator according to claim 14, further comprising an overpressure valve connected to said high-pressure fuel vessel to prevent overpressurization. ### Claim 16 (depends on 13) An electrical generator according to claim 13, further comprising at least two positive displacement chambers. ### Claim 17 (depends on 13) An electrical generator according to claim 13, further comprising an intake manifold. ### Claim 18 (depends on 17) An electrical generator according to claim 17, further comprising a throttle valve for controlling the amount of compressed gas from the combustion chamber to the intake manifold. ### Claim 19 (depends on 13) An electrical generator according to claim 13, further comprising at least one check valve and at least one pressure regulator for controlling the flow of compressed air from the high-pressure air vessel to the combustion chamber. ### Claim 20 (depends on 14) An electrical generator according to claim 14, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 1000 pounds per square inch. ### Claim 21 (depends on 14) An electrical generator according to claim 14, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 2000 pounds per square inch. ### Claim 22 (depends on 14) An electrical generator according to claim 14, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 3000 pounds per square inch. ### Claim 23 (depends on 14) An electrical generator according to claim 14, wherein said high-pressure fuel and air vessels are capable of containing pressures of at least about 3500 pounds per square inch. ### Claim 24 (depends on 13) An electrical generator according to claim 13, further comprising a safety valve connected to the combustion chamber for allowing excess pressure to be vented from the combustion chamber. ### Claim 25 (depends on 13) An electrical generator according to claim 13, further comprising an air compressor driven by said engine in communication with said high-pressure air vessel. ### Claim 26 (depends on 13) An electrical generator according to claim 13, further comprising an air compressor driven by another engine in communication with said high-pressure air vessel. ### Claim 27 (depends on 13) An electrical generator according to claim 13, further comprising an air compressor driven by high pressure natural gas from the high pressure main line in communication with said high-pressure air vessel.