Aircraft Rotary Engine Rotor Lubrication Passages for Apex Cooling

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Solution Overview

Problem

Existing rotary engine rotors for aircraft lack effective cooling and lubrication systems, particularly at the apex seals, which are critical for efficient operation.

Innovation Solution

The rotor design incorporates lubricant passages at the apex portions and within the ribs, with outlets at the annular inner body portion, facilitating improved cooling and lubrication of the intermediate body and bearing inner race.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If lubricant passages are positioned at the apex portions, then cooling efficiency of the intermediate body is improved, but device complexity increases

Engineering Contradiction:
Improvecooling efficiencyVSAvoidpassage configuration complexity
Core Design Contradiction:
TemperatureVSDevice complexity

Solution Approach 1:

The lubricant passages are strategically positioned at the apex portions where heat generation is highest, concentrating cooling resources where they are most needed. This localizes the cooling function to critical areas rather than uniformly distributing it throughout the intermediate body.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The lubricant passage system is divided into multiple separate passages distributed at different apex portions, allowing independent optimization of each passage while collectively providing comprehensive cooling across the heat-generating regions.

Inventive Principle:
Principle #1Segmentation

2Reliability

If multiple lubricant passages are implemented, then lubrication coverage is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvelubrication coverageVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

Multiple lubricant passages are integrated into a single monolithic rotor component, combining the lubrication function across different apex portions within one piece rather than requiring separate assemblies or complex multi-step manufacturing processes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The rotor body serves multiple functions simultaneously: it provides structural support, contains the combustion chambers, and houses the lubricant passage system. This multi-functionality reduces the need for separate lubrication components and simplifies the overall assembly.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

Enhances cooling and lubrication efficiency, reducing the need for excessive lubricant and cooling, thereby improving rotor performance and reliability.

Implementation Method 1

The rotor body is provided with a first lubrication passage extending from a first end body through the intermediate body to a second end body

Methodology Applied
Scientific EffectFluid flow through passages:

Implementation Method 2

By arranging the location of the lubricant passages at the apex portions it is facilitated a greater cooling of the intermediate body in proximity to the apex seals

Methodology Applied
Scientific EffectThermal convection cooling: Convection

Data Source

PatentEP4442957B1Rotor for a rotary engine
Publication Date: 2026.01.14 PRATT & WHITNEY CANADA CORP
  • EP4442957B1 patent drawingFigure 1
  • EP4442957B1 patent drawingFigure 2
  • EP4442957B1 patent drawingFigure 3

AI summary

A rotor (48) for an aircraft rotary engine (12) includes a rotor body (84). The rotor body (84) extends about an axial centerline (86). The rotor body (84) includes an outer body portion (96), an annular inner body portion (98), and ribs (100). The outer body portion (96) forms a plurality of sides (72) and a plurality of apex portions (76) of the rotor (48). The annular inner body portion (98) is disposed radially inward of the outer body portion (96). The ribs (100) extend radially between and connect the outer body portion (96) and the annular inner body portion (98). The rotor body (84) forms at least a first lubrication passage (120) within the inner body portion (98) and within a first rib (100) of the ribs (100). The first lubrication passage (120) includes at least one passage inlet (122) and at least one passage outlet (124). The at least one passage inlet (122) is disposed at the annular inner body portion (98).