# US 9,752,485 B2 · Exhaust gas energy recovery system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,752,485 B2 - Document ID: US9752485B2 - Status: Granted - Kind: B2 - Application number: 14/790,578 - Filed: 2015-07-02 - Published: 2015-10-22 - Granted: 2017-09-05 - Earliest claimed: 2013-01-03 - Assignees: Eaton Corporation - Applicants: Eaton Corporation - Inventors: William Nicholas Eybergen; Swami Nathan Subramanian - Web page: https://patentgrep.com/patent/US9752485B2 ## CPC - F01N 5/02: the devices using heat - F01N 5/04: the devices using kinetic energy - F02D 41/0007: {for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12)} - F02D 2250/34: Control of exhaust back pressure, e.g. for turbocharged engines - F05D 2220/32: in gas turbines - F05D 2220/60: making use of surplus or waste energy - F05D 2260/40311: of the epicyclical, planetary or differential type - F05D 2260/42: Storage of energy - Y02T 10/12: Improving ICE efficiencies - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract An exhaust gas energy recovery system includes a power plant and a volumetric fluid expander. The power plant has an exhaust gas outlet for conveying an exhaust gas stream at a first pressure. The volumetric fluid expander includes a housing and an output shaft. The housing has an inlet and an outlet, and the housing inlet is in fluid communication with the exhaust gas outlet. The volumetric fluid expander generates useful work at the output shaft by expanding the exhaust gas stream to a second pressure lower than the first pressure generally without reducing the volume of the exhaust stream as the exhaust stream moves from the housing inlet to the outlet. ## Claims ### Claim 1 An exhaust gas energy recovery system comprising: an engine having an intake manifold and an exhaust manifold; and a volumetric fluid expander receiving a first exhaust stream, expanding the first exhaust stream to a second exhaust stream, generating a mechanical work, and discharging the second exhaust stream, the second exhaust stream having a lower pressure than the first exhaust stream, wherein the volumetric fluid expander includes a housing having an inlet port and an outlet port, the inlet port in fluid communication with the exhaust manifold and configured to receive the first exhaust stream from the exhaust manifold, and the outlet port in fluid communication with the intake manifold and configured to discharge the second exhaust stream, wherein the volumetric fluid expander further comprising: a plurality of meshed rotors disposed in the housing and configured to expand the first exhaust stream into the second exhaust stream; and an output shaft operatively connected to one of the plurality of rotors and rotated by the exhaust as the exhaust undergoes expansion through the plurality of rotors within the housing. ### Claim 2 (depends on 1) The system of claim 1, wherein the inlet port is directly in fluid communication with the exhaust manifold, and the outlet port is directly in fluid communication with the intake manifold. ### Claim 3 (depends on 1) The system of claim 1, wherein the plurality of rotors includes first and second twisted meshed rotors rotatably disposed in the housing, wherein each rotor has a plurality of non-contacting lobes of an equal number. ### Claim 4 (depends on 1) The system of claim 1, further comprising a generator configured to control the volumetric fluid expander to adjust an amount of the second exhaust stream discharged from the volumetric fluid expander. ### Claim 5 (depends on 1) The system of claim 1, further comprising a generator configured to control a rotational speed of the rotors to adjust an amount of the second exhaust stream discharged from the volumetric fluid expander. ### Claim 6 (depends on 1) The system of claim 1, further comprising an energy storage device, wherein a mechanical work generated by the volumetric fluid expander is accumulated in the energy storage device for subsequent release on demand. ### Claim 7 (depends on 6) The system of claim 6, wherein the energy storage device is a battery or an accumulator. ### Claim 8 A volumetric fluid expander for an engine, the engine having an intake manifold and an exhaust manifold, the expander comprising: a housing having an inlet port and an outlet port, the inlet port in fluid communication with the exhaust manifold and configured to receive a first exhaust stream from the exhaust manifold, and the outlet port in fluid communication with the intake manifold and configured to discharge a second exhaust stream, the second exhaust stream having a lower pressure or temperature than the first exhaust stream; a plurality of meshed rotors disposed in the housing and configured to expand the first exhaust stream into the second exhaust stream; and an output shaft operatively connected to one of the plurality of rotors and rotated by the exhaust to generate a mechanical work as the exhaust undergoes expansion through the plurality of rotors within the housing. ### Claim 9 (depends on 8) The expander of claim 8, wherein the plurality of rotors includes first and second twisted meshed rotors rotatably disposed in the housing, wherein each rotor has a plurality of non-contacting lobes of an equal number. ### Claim 10 (depends on 8) The expander of claim 8, wherein the inlet port is directly in fluid communication with the exhaust manifold, and the outlet port is directly in fluid communication with the intake manifold. ### Claim 11 (depends on 8) The expander of claim 8, further comprising a generator configured to control the volumetric fluid expander to adjust a volume of the second exhaust stream discharged from the volumetric fluid expander. ### Claim 12 (depends on 11) The expander of claim 11, wherein the generator is configured to control a rotational speed of the rotors. ### Claim 13 (depends on 8) The expander of claim 8, further comprising an energy storage device, wherein a mechanical work generated by the volumetric fluid expander is accumulated in the energy storage device for subsequent release on demand. ### Claim 14 (depends on 13) The expander of claim 13, wherein the energy storage device is a battery or an accumulator. ### Claim 15 A generator for a volumetric fluid expander, the volumetric fluid expander comprising: a housing having an inlet port and an outlet port, the inlet port in fluid communication with an exhaust manifold of an internal combustion engine and configured to receive a first exhaust stream from the exhaust manifold, and the outlet port in fluid communication with an intake manifold of the engine and configured to discharge a second exhaust stream, the second exhaust stream having a lower pressure or temperature than the first exhaust stream; a plurality of meshed rotors disposed in the housing and configured to expand the first exhaust stream into the second exhaust stream; and an output shaft operatively connected to one of the plurality of rotors and rotated by the exhaust to generate a mechanical work as the exhaust undergoes expansion through the plurality of rotors within the housing, wherein the generator is configured to control a rotational speed of the rotors to adjust an amount of the second exhaust stream discharged from the housing of the volumetric fluid expander. ### Claim 16 An exhaust gas energy recovery system comprising: a. a power plant having an exhaust gas outlet for conveying an exhaust gas stream at a first pressure; and b. a volumetric fluid expander including: i. a housing having an inlet and an outlet, the housing inlet being in fluid communication with the exhaust gas outlet; ii. an output shaft; c. wherein the volumetric fluid expander is configured to generate useful work at the output shaft by expanding the exhaust gas stream to a second pressure lower than the first pressure generally without reducing the volume of the exhaust stream as the exhaust stream moves from the housing inlet to the outlet, wherein the volumetric fluid expander includes: a. first and second twisted meshed rotors rotatably disposed in the housing, wherein the rotors have an equal number of lobes, and wherein the lobes of the first rotor do not contact the lobes of the second rotor. ### Claim 17 (depends on 16) The exhaust gas energy recovery system of claim 16, wherein the power plant is a fuel cell. ### Claim 18 (depends on 16) The exhaust gas energy recovery system of claim 16, wherein the power plant is a combustion engine of a vehicle. ### Claim 19 (depends on 16) The exhaust gas energy recovery system of claim 16, wherein the volumetric fluid expander output shaft is mechanically coupled to an output shaft of the power plant. ### Claim 20 (depends on 16) The exhaust gas energy recovery system of claim 16, wherein the volumetric fluid expander output shaft is mechanically coupled to a generator. ### Claim 21 (depends on 19) The exhaust gas energy recovery system of claim 19, wherein the volumetric fluid expander output shaft is additionally coupled to a generator or a hydraulic pump. ### Claim 22 (depends on 21) The exhaust gas energy recovery system of claim 21, wherein a variable speed drive system connects the expander output shaft to the output shaft of the power plant and to the generator or hydraulic pump. ### Claim 23 (depends on 22) The exhaust gas energy recovery system of claim 22, wherein the variable speed drive system is a planetary gear set having a sun gear, a ring gear, and a plurality of planet gears between the sun and the ring gears. ### Claim 24 (depends on 23) The exhaust gas energy recovery system of claim 23, wherein the sun gear is coupled to the volumetric fluid expander output shaft, the planet gears are coupled to the power plant output shaft, and the ring gear is coupled to the generator or hydraulic pump.