# US 12,601,277 B2 · Turbfan engine

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- Number: US 12,601,277 B2
- Document ID: US12601277B2
- Status: Granted
- Kind: B2
- Application number: 18/536,449
- Filed: 2023-12-12
- Published: 2024-06-27
- Granted: 2026-04-14
- Earliest claimed: 2022-12-16
- Assignees: MTU Aero Engines AG
- Applicants: MTU Aero Engines AG
- Inventors: Jens Truebenbach; Jan Von Frowein
- Web page: https://patentgrep.com/patent/US12601277B2

## CPC

- F01D 5/02: Blade-carrying members, e.g. rotors (rotors of non-bladed type F01D1/34; stators F01D9/00 {; selecting particular materials F01D5/28})
- F01D 15/12: Combinations with mechanical gearing (driven by multiple engines F01D13/00)
- F02C 7/32: Arrangement, mounting, or driving, of auxiliaries
- 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 3/06: with front fan
- F05D 2220/323: for aircraft propulsion, e.g. jet engines
- F05D 2240/20: Rotors
- F05D 2240/24: for turbines
- F05D 2240/30: Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
- F05D 2240/60: Shafts
- F05D 2260/40: Transmission of power
- F05D 2260/40311: of the epicyclical, planetary or differential type
- Y02T 50/60: Efficient propulsion technologies, e.g. for 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)
- 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

A turbofan engine with a low-pressure turbine module having no more than four stages and a fan coupled to the low-pressure turbine module via a gearbox, the turbofan engine having a maximum thrust of at least 70 kN and at most 300 kN, and the low-pressure turbine module (4.2) having a ratio of the exit annulus area to the inlet annulus area, Aout/Ain, of at least 2.2 and at most 3.3.

## Claims

### Claim 1

A turbofan engine comprising:
a low-pressure turbine module having no more than four stages; and
a fan coupled to the low-pressure turbine module via a gearbox, the turbofan engine having a maximum thrust of at least 110 kN and at most 140 kN,
and wherein the low-pressure turbine module has a ratio of the exit annulus area to the inlet annulus area, Aout/Ain, of at least 2.2 and at most 3.3,
the fan having a diameter of at least 204 cm and at most 247 cm.

### Claim 2 (depends on 1)

The turbofan engine as recited in claim 1 wherein the turbofan engine has a maximum thrust of at most 250 kN.

### Claim 3 (depends on 2)

The turbofan engine as recited in claim 2 wherein the maximum thrust is at most 200 kN.

### Claim 4 (depends on 3)

The turbofan engine as recited in claim 3 wherein the maximum thrust is at most 170 kN.

### Claim 5 (depends on 1)

The turbofan engine as recited in claim 1 wherein the diameter is at most 219 cm.

### Claim 6 (depends on 1)

The turbofan engine as recited in claim 1 wherein the low-pressure turbine module has an axial length of at least 20 cm and at most 32 cm.

### Claim 7 (depends on 6)

The turbofan engine as recited in claim 6 wherein the axial length is at most 22 cm.

### Claim 8 (depends on 1)

The turbofan engine as recited in claim 1 wherein the low-pressure turbine module is a three-stage design, and a ratio Aout/Ain of the low-pressure turbine module is at least 2.2 and at most 2.4.

### Claim 9 (depends on 1)

The turbofan engine as recited in claim 1 wherein the low-pressure turbine module is a four-stage design, and a ratio Aout/Ain of the low-pressure turbine module is at least 2.5 and at most 3.3.

### Claim 10 (depends on 1)

The turbofan engine as recited in claim 1 wherein a bypass ratio is at least 12:1 and at most 15:1.

### Claim 11 (depends on 1)

The turbofan engine as recited in claim 1 wherein a redline rotational speed of the low-pressure turbine module is at least 6,500 rpm and at most 14,500 rpm.

### Claim 12 (depends on 1)

An aircraft comprising the turbofan engine as recited in claim 1.

### Claim 13 (depends on 1)

A method of operating the turbofan engine as recited in claim 1 comprising: operating the turbofan engine below or at the maximum thrust.

### Claim 14 (depends on 13)

The method as recited in claim 13, wherein the low-pressure turbine module rotates at a speed of 6,500-14,500 rpm.