# US 11,305,883 B2 · Circulating coolant fluid in hybrid electrical propulsion systems > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,305,883 B2 - Document ID: US11305883B2 - Status: Granted - Kind: B2 - Application number: 16/706,281 - Filed: 2019-12-06 - Published: 2020-09-03 - Granted: 2022-04-19 - Earliest claimed: 2019-03-01 - Assignees: United Technologies Advanced Projects Inc. - Applicants: Pratt & Whittney Canada Corp. - Inventors: Jean Dubreuil; Eric LaTulipe - Web page: https://patentgrep.com/patent/US11305883B2 ## CPC - F01M 1/02: using lubricating pumps (pumps in general F04; lubricating pumps per se F16N) - B64D 27/026: {comprising different types of power plants, e.g. combination of a piston engine and a gas-turbine (Hybrid electric aircraft B64D27/33)} - B64D 27/33: Hybrid electric aircraft - B64D 33/08: of power plant cooling systems - B64D 35/023: of series-parallel type - B64D 35/024: of series type - F01D 25/12: Cooling - F01D 25/18: Lubricating arrangements (of machines or engines in general F01M) - F01D 25/20: using lubrication pumps - F01M 1/10: Lubricating systems characterised by the provision therein of lubricant venting or purifying means, e.g. of filters - F01M 5/002: {Cooling} - F01M 11/0004: {Oilsumps} - F01M 11/03: Mounting or connecting of lubricant purifying means relative to the machine or engine; Details of lubricant purifying means (filters B01D) - F02C 7/06: Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M) - F02C 7/36: Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user ({F02C3/107 - F02C3/13 and} F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H) - F02K 5/00: Plants including an engine, other than a gas turbine, driving a compressor or a ducted fan - F16H 57/0404: {Lubricant filters} - F16H 57/0416: {Air cooling or ventilation} - F16H 57/0436: {Pumps} - F16H 57/0475: {Engine and gearing, i.e. joint lubrication or cooling or heating thereof} - F16H 57/0476: {Electric machines and gearing, i.e. joint lubrication or cooling or heating thereof} - H02K 7/116: with gears - H02K 9/19: for machines with closed casing and closed-circuit cooling using a liquid cooling medium, e.g. oil - H02K 9/26: Structural association of machines with devices for cleaning or drying cooling medium, e.g. with filters - H02K 11/25: Devices for sensing temperature, or actuated thereby - F01M 2005/004: {Oil-cooled engines} - F01M 2011/033: {comprising coolers or heat exchangers} - F01M 2011/038: {comprising lubricant-air separators} - F01M 2250/60: Operating parameters - F05D 2260/213: by the provision of a heat exchanger within the cooling circuit - F05D 2260/98: Lubrication - F16N 2210/02: Turbines - F16N 2210/08: Aircraft - F16N 2210/12: Gearings - F01M: LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING - B64D: EQUIPMENT FOR FITTING IN OR TO AIRCRAFT; FLIGHT SUITS; PARACHUTES; ARRANGEMENT OR MOUNTING OF POWER PLANTS OR PROPULSION TRANSMISSIONS IN AIRCRAFT - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F02C: GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS (construction of turbines F01D; jet-propulsion plants F02K; construction of compressors or fans F04; generating combustion products of high pressure or high velocity F23R; using gas turbines in compression refrigeration plants F25B11/00) - F02K: JET-PROPULSION PLANTS (features of jet-propulsion plants common to gas-turbine plants, air intakes or fuel supply control of air-breathing jet-propulsion plants F02C7/00, F02C9/00) - F16H: GEARING - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS - F16N: LUBRICATING ## Abstract A hybrid propulsion system includes a heat engine configured to drive a heat engine shaft. An electric motor configured to drive a motor shaft. A transmission system is connected to receive rotational input power from each of the heat engine shaft and the motor shaft and to convert the rotation input power to output power. A first lubrication/coolant system is connected for circulating a first lubricant/coolant fluid through the heat engine. A second lubricant/coolant system in fluid isolation from the first lubrication/coolant system is connected for circulating a second lubricant/coolant fluid through the electric motor. ## Claims ### Claim 1 A hybrid propulsion system comprising: a heat engine configured to drive a heat engine shaft; an electric motor configured to drive a motor shaft; a transmission system connected to receive rotational input power from each of the heat engine shaft and the motor shaft and to convert the rotation input power to output power; a first lubrication/coolant system connected for circulating a first lubricant/coolant fluid through the heat engine; a second lubricant/coolant system in fluid isolation from the first lubrication/coolant system, wherein the second lubricant/coolant system is connected for circulating a second lubricant/coolant fluid through the electric motor; a turbine gearbox connecting between the heat engine and a shaft for rotation of a compressor and a turbine at a rotational speed different from that of the heat engine; and a pressure pump operatively connected to be powered by the turbine gearbox, wherein the pressure pump is connected in a coolant line of the first lubrication/coolant system between a sump tank and the heat engine for driving flow of the first lubricant/coolant from the sump tank to the heat engine. ### Claim 2 (depends on 1) The system as recited in claim 1, further comprising: a cooler in the coolant line between the sump tank and the heat engine downstream of the pressure pump for cooling the first lubricant/coolant with a flow of ambient air. ### Claim 3 (depends on 2) The system as recited in claim 2, further comprising: a filter in the coolant line between the sump tank and the heat engine; and/or a coolant pressure sensor in the coolant line between the sump tank and the heat engine downstream of the cooler; and/or a coolant temperature sensor in the coolant line between the sump tank and the heat engine downstream of the cooler. ### Claim 4 (depends on 1) The system as recited in claim 1, wherein the coolant line branches into respective coolant sub-lines connected for circulating the first lubricant/coolant to the heat engine, the turbine gearbox, the compressor, and the turbine. ### Claim 5 (depends on 4) The system as recited in claim 4, wherein the coolant line includes a coolant sub-line that connects through a hydraulic motor to the sump tank. ### Claim 6 (depends on 4) The system as recited in claim 4, further comprising a plurality of scavenge passages connecting for return of the first lubricant/coolant fluid from the heat engine, the turbine gearbox, the compressor, and the turbine. ### Claim 7 (depends on 6) The system as recited in claim 6, wherein a respective scavenge passage from the compressor to the sump tank includes a first scavenge pump operatively connected a hydraulic motor to drive scavenge flow of the first lubricant/coolant from the compressor to the sump tank, and wherein a respective scavenge passage from the turbine to the sump tank includes a second scavenge pump operatively connected the hydraulic motor to drive scavenge flow of the first lubricant/coolant from the turbine to the sump tank. ### Claim 8 (depends on 7) The system as recited in claim 7, further comprising a chip detector in a line downstream from at least one of the first and second scavenge pumps. ### Claim 9 (depends on 1) The system as recited in claim 1, wherein the pressure pump provides driving potential for the first lubrication/coolant system entirely. ### Claim 10 (depends on 1) The system as recited in claim 1, wherein the pressure pump is located in a u-bend in the coolant line. ### Claim 11 (depends on 1) The system as recited in claim 1, wherein the sump tank includes an anti-siphon device connected to the coolant line. ### Claim 12 (depends on 1) The system as recited in claim 1, wherein no anti-siphon device is included connecting the sump tank to the coolant line, and wherein a chip detector is included within the sump tank. ### Claim 13 (depends on 1) The system as recited in claim 1, further comprising: a first scavenge passage from the compressor to the sump tank including a first scavenge pump operatively connected the turbine gearbox to drive scavenge flow of the first lubricant/coolant from the compressor to the sump tank; a second scavenge passage from the turbine to the sump tank including a second scavenge pump operatively connected the turbine gearbox to drive scavenge flow of the first lubricant/coolant from the turbine to the sump tank; and a third scavenge passage from the heat engine to the sump tank including a third scavenge pump operatively connected to the turbine gearbox to drive scavenge flow of the first lubricant/coolant from the heat engine to the sump tank. ### Claim 14 (depends on 13) The system as recited in claim 13, wherein the sump tank includes a partition for consolidating scavenge flows from the heat engine into the third scavenge passage, and separating the scavenge flows from the heat engine from a main sump volume fed by the first, second, and third scavenge pumps, and further comprising a chip sensor in the third scavenge line. ### Claim 15 A hybrid propulsion system comprising: a heat engine configured to drive a heat engine shaft; an electric motor configured to drive a motor shaft; a transmission system connected to receive rotational input power from each of the heat engine shaft and the motor shaft and to convert the rotation input power to output power; a first lubrication/coolant system connected for circulating a first lubricant/coolant fluid through the heat engine; a second lubricant/coolant system in fluid isolation from the first lubrication/coolant system, wherein the second lubricant/coolant system is connected for circulating a second lubricant/coolant fluid through the electric motor; a combining gearbox connected to the heat engine and to the electric motor for combining power from the heat engine and electric motor to provide output power; and a pressure pump operatively connected to be powered by the combining gear box, wherein the pressure pump is connected in a coolant line of the second lubricant/coolant system between a sump tank and the electric motor for driving flow of the second lubricant/coolant from the sump tank to the electric motor. ### Claim 16 (depends on 15) The system as recited in claim 15, wherein the coolant line includes a cooler for cooling the second lubricant/coolant with ambient air, and wherein the coolant line branches to supply the second lubricant/coolant to the combining gearbox and to the electric motor. ### Claim 17 (depends on 16) The system as recited in claim 16, further comprising a scavenge passage operatively connecting between a sump tank of the second lubricant/coolant system and the electric motor and the combining gearbox, wherein a scavenge pump is included in the scavenge passage. ### Claim 18 (depends on 17) The system as recited in claim 17, further comprising: a reduction gearbox operatively connected to receive power output from the combining gearbox, wherein the coolant line includes a branch for supplying the second lubricant/coolant to the reduction gearbox; a scavenge passage branch connecting between the reduction gearbox and the scavenge passage; and a second scavenge pump in the scavenge passage branch for driving flow from the reduction gearbox to the sump tank. ### Claim 19 (depends on 1) The system as recited in claim 1, further comprising a third coolant system connected for circulating a third coolant fluid through the heat engine. ### Claim 20 (depends on 19) The system as recited in claim 19, further comprising a compressor connected through an air line to supply boost air to the heat engine, wherein the air line includes an intercooler for cooling the compressed air, wherein the third coolant system is connected to the intercooler for heat exchange between the third coolant and the compressed air. ### Claim 21 (depends on 1) The system as recited in claim 1, wherein the heat engine shaft and the motor shaft are combined as a single common shaft connected to the transmission system.