# US 11,028,775 B2 · Bleed air boosted engine oil cooler

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 11,028,775 B2
- Document ID: US11028775B2
- Status: Granted
- Kind: B2
- Application number: 16/110,043
- Filed: 2018-08-23
- Published: 2020-02-27
- Granted: 2021-06-08
- Earliest claimed: 2018-08-23
- Assignees: The Boeing Company
- Applicants: The Boeing Company
- Inventors: Steve G. Mackin; Samuel J. Tutko
- Web page: https://patentgrep.com/patent/US11028775B2

## CPC

- F02C 7/14: of fluids in the plant {, e.g. lubricant or fuel (F02C7/185 takes precedence)}
- F02K 3/06: with front fan
- F01D 25/20: using lubrication pumps
- F01M 5/002: {Cooling}
- F02C 6/08: the gas being bled from the gas-turbine compressor
- F02C 7/06: Arrangements of bearings (bearings F16C); Lubricating ({of turbo machines F01D25/18; of machines or} engines in general F01M)
- F02C 7/18: the medium being gaseous, e.g. air {(F02C7/125 takes precedence)}
- F02C 7/185: {Cooling means for reducing the temperature of the cooling air or gas}
- F02C 9/18: by bleeding, bypassing or acting on variable working fluid interconnections between turbines or compressors or their stages {(F02C3/113 takes precedence)}
- F02K 3/115: by means of indirect heat exchange
- F02C 3/32: Inducing air flow by fluid jet, e.g. ejector action
- F05D 2220/323: for aircraft propulsion, e.g. jet engines
- F05D 2260/213: by the provision of a heat exchanger within the cooling circuit
- F05D 2260/601: using an ejector or a jet pump
- F05D 2260/98: Lubrication
- Y02T 50/60: Efficient propulsion technologies, e.g. for aircraft
- 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)
- F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D)
- F01M: LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
- 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 aircraft engine system has a turbofan engine with a lubricating oil system. An oil pump is connected to pump oil from the oil tank through a cooling circuit to the turbofan engine. The cooling circuit has a bleed air boosted engine oil cooler assembly with a liquid/air heat exchanger (LAHEX) connected to an oil inlet conduit and receiving fan air from a high bypass fan of the turbofan engine as the cooling working fluid. The LAHEX is connected to an oil exit conduit. An ejector downstream of the LAHEX receives bleed air from a compressor section of the turbofan engine. The ejector draws the fan air through the LAHEX.

## Claims

### Claim 1

An aircraft engine system comprising:
a turbofan engine having a core including a compressor section and further having a lubricating oil system;
an oil pump connected to pump oil from the lubricating oil system through a cooling circuit to the turbofan engine, said cooling circuit having a bleed air boosted engine oil cooler assembly with
a liquid/air heat exchanger (LAHEX) connected to an oil inlet conduit and receiving fan air from a fan of the turbofan engine as a cooling working fluid, said LAHEX connected to an oil exit conduit, and
an ejector downstream of the LAHEX receiving bleed air from the compressor section of the turbofan engine, said ejector drawing the fan air through the LAHEX;
an outlet duct from an air side outlet of the LAHEX connected to exhaust the fan air, said ejector having a primary nozzle ejecting the bleed air into the outlet duct;
a bleed valve connected through a bleed conduit to the primary nozzle, said bleed valve having a closed position preventing flow of bleed air to the bleed conduit and an open position allowing flow of bleed air to the bleed conduit,
a core speed sensor detecting speed of the core;
an oil temperature sensor; and
a valve control module receiving input from the core speed senor and oil temperature sensor and, responsive to a deceleration of the core, issuing a control signal to the bleed valve placing the bleed valve in the open position to protect operability margin even if oil temperature is not hotter than a trigger threshold.

### Claim 2 (depends on 1)

The aircraft engine system as defined in claim 1 wherein the cooling circuit further comprises at least one additional heat exchanger connected to provide oil cooling to supplement the bleed air boosted engine oil cooler assembly.

### Claim 3 (depends on 2)

The aircraft engine system as defined in claim 2 wherein the at least one additional heat exchanger comprises a main fuel/oil LLHEX connected to provide oil cooling employing fuel, pumped from aircraft fuel tanks through feed lines for use by engine combustors, as a liquid cooling working fluid through a first feed line receiving fuel from a fuel pump supplying the fuel to a combustor supply inlet, the main fuel/oil LLHEX connected to the oil exit conduit.

### Claim 4

An aircraft engine system comprising:
a turbofan engine having a lubricating oil system;
an oil pump connected to pump oil from the lubricating oil system through a cooling circuit to the turbofan engine, said cooling circuit having a bleed air boosted engine oil cooler assembly with
a liquid/air heat exchanger (LAHEX) connected to an oil inlet conduit and receiving fan air from a fan of the turbofan engine as a cooling working fluid, said LAHEX connected to an oil exit conduit,
an ejector downstream of the LAHEX receiving bleed air from a compressor section of the turbofan engine, said ejector drawing the fan air through the LAHEX, and
a main fuel/oil LLHEX connected to provide oil cooling employing fuel, pumped from aircraft fuel tanks through feed lines for use by engine combustors, as a liquid cooling working fluid through a first feed line receiving fuel from a fuel pump supplying the fuel to a combustor supply inlet, the main fuel/oil LLHEX connected to the oil exit conduit to provide oil cooling to supplement the bleed air boosted engine oil cooler assembly; and
a servo fuel heater LLHEX connected to bypass fuel from a second stage fuel pump through a servo loop, said servo fuel heater LLHEX connected to the oil inlet conduit.

### Claim 5 (depends on 4)

The aircraft engine system as defined in claim 4 wherein the bleed air boosted engine oil cooler assembly further comprises:
an inlet duct at an air side inlet of the LAHEX connected to a fan duct to receive the fan air; and,
an outlet duct from an air side outlet of the LAHEX connected to the fan duct to exhaust the fan air, said ejector having a primary nozzle ejecting the bleed air into the outlet duct.

### Claim 6 (depends on 5)

The aircraft engine system as defined in claim 5 wherein the inlet duct has an inlet aperture flush with the fan duct.

### Claim 7 (depends on 5)

The aircraft engine system as defined in claim 5 wherein the outlet duct has an outlet aperture flush with the fan duct.

### Claim 8 (depends on 5)

The aircraft engine system as defined in claim 5 further comprising
a bleed valve connected through a bleed conduit to the primary nozzle, said bleed valve having a closed position preventing flow of bleed air to the bleed conduit and an open position allowing flow of bleed air to the bleed conduit, and
a valve control module responsive to a deceleration of a core of the turbofan engine issuing a control signal to the bleed valve placing the bleed valve in the open position.

### Claim 9 (depends on 8)

The aircraft engine system as defined in claim 8 wherein the valve control module is further responsive to a signal from a temperature sensor issuing the control signal to the bleed valve placing the bleed valve in the open position upon exceeding a threshold temperature.

### Claim 10

A bleed air boosted engine oil cooler assembly comprising
a liquid/air heat exchanger (LAHEX) connected to an oil inlet conduit and receiving fan air from a fan of a turbofan engine as a cooling working fluid, said LAHEX connected to an oil exit conduit,
an ejector downstream of the LAHEX receiving bleed air from a compressor section of the turbofan engine, said ejector drawing the fan air through the LAHEX;
an outlet duct from an air side outlet of the LAHEX connected to exhaust the fan air, said ejector having a primary nozzle ejecting the bleed air into the outlet duct;
a bleed valve connected through a bleed conduit to the primary nozzle, said bleed valve having a closed position preventing flow of bleed air to the bleed conduit and an open position allowing flow of bleed air to the bleed conduit,
a core speed sensor detecting speed of the core of the turbofan engine;
an oil temperature sensor; and
a valve control module receiving input from the core speed senor and oil temperature sensor and, responsive to a deceleration of the core, issuing a control signal to the bleed valve placing the bleed valve in the open position to protect operability margin even if oil temperature is not hotter than a trigger threshold temperature.

### Claim 11 (depends on 10)

The bleed air boosted engine oil cooler assembly as defined in claim 10 further comprising:
an inlet duct at an air side inlet of the LAHEX connected to a fan duct to receive the fan air; and,
the outlet duct is connected to the fan duct to exhaust the fan air.

### Claim 12 (depends on 11)

The bleed air boosted engine oil cooler assembly as defined in claim 11 wherein the inlet duct has an inlet aperture flush with the fan duct.

### Claim 13 (depends on 11)

The bleed air boosted engine oil cooler assembly as defined in claim 11 wherein the outlet duct has an outlet aperture flush with the fan duct.

### Claim 14 (depends on 10)

The bleed air boosted engine oil cooler assembly as defined in claim 10 wherein the valve control module is further responsive to a signal from the temperature sensor issuing the control signal to the bleed valve placing the bleed valve in the the open position upon exceeding the trigger threshold temperature.

### Claim 15

A method for cooling turbofan engine oil of a turbofan engine comprising:
monitoring engine core speed with a core speed sensor;
monitoring engine oil temperature with an oil temperature sensor;
providing the engine oil through an inlet conduit for cooling in a bleed air boosted engine oil cooler assembly having a liquid/air heat exchanger (LAHEX), the LAHEX receiving fan air from a fan of the turbofan engine as a cooling working fluid, said engine oil exiting through an exit conduit, wherein the bleed air boosted engine oil cooler assembly has an ejector receiving bleed air from a compressor section of the turbofan engine, said ejector drawing the fan air through the LAHEX with an outlet duct from an air side outlet of the LAHEX connected to exhaust the fan air, said ejector having a primary nozzle ejecting the bleed air into the outlet duct and a bleed valve is connected through a bleed conduit to the primary nozzle, said bleed valve having a closed position preventing flow of bleed air to the bleed conduit and an open position allowing flow of bleed air to the bleed conduit, and a valve control module receiving input from the core speed sensor and oil temperature sensor; and
issuing a control input from the valve control module to the bleed valve to open the bleed valve, bleeding the bleed air from an engine compressor section through the bleed conduit to the ejector in the outlet duct of the bleed air boosted engine oil cooler assembly if the engine core speed is decelerating to protect operability margin even if the oil temperature is not hotter than a trigger threshold temperature.

### Claim 16 (depends on 15)

The method as defined in claim 15, further comprising enhancing a stability margin of the engine compressor section by extraction of the bleed air.

### Claim 17 (depends on 15)

The method as defined in claim 15 further comprising: issuing the control input to the bleed valve to open the bleed valve if the engine oil temperature exceeds the trigger threshold temperature.

### Claim 18 (depends on 15)

The method as defined in claim 15 further comprising:
entraining heated fan air drawn through the LAHEX in a secondary nozzle using the bleed air ejected through the primary nozzle of the ejector to create a mixed flow;
inducing pressure reduction by the ejector in the outlet duct of the bleed air boosted engine oil cooler assembly and causing pumping of fan air through the LAHEX, increasing fin efficiency and inducing enhanced ingestion of the fan air from a fan duct through a flush inlet aperture into an inlet duct of the bleed air boosted engine oil cooler assembly.

### Claim 19 (depends on 18)

The method as defined in claim 18 further comprising exhausting the mixed flow with energized velocity through a flush outlet aperture of the outlet duct into the fan duct, said heated fan air introduced into the mixed flow providing additional thrust recovery in the fan duct.

### Claim 20 (depends on 18)

The method as defined in claim 18 further comprising recovering additional thrust by introduction of heated fan air into the mixed flow.