Aircraft Engine Air Filter with Shutter for Altitude Bypass

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Solution Overview

Problem

Modern helicopter engines face increased maintenance costs due to wear from foreign bodies during take-off and landing, as air filters are typically not used at high altitudes where impurities are rare, but their absence allows impurities to enter the combustion chamber, causing engine wear.

Innovation Solution

An air filter system with a tubular housing and a shutter device that can move between closed and open positions, allowing air to bypass the filtering material at high altitudes to prevent performance reduction, controlled by an electronic unit and pressure sensor to optimize operation based on altitude and air purity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an air filter is installed to prevent impurities from entering the combustion chamber, then engine wear is reduced and reliability is improved, but performance is degraded due to load losses

Engineering Contradiction:
Improveengine reliabilityVSAvoidengine performance
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent implements a dynamic air filter system where the filter element can be selectively positioned in the air intake path based on operating conditions. During takeoff and landing operations when impurities are present, the filter is positioned to capture particles. During cruise flight at high altitudes where air is clean, the filter is repositioned to minimize flow resistance, thus optimizing engine performance while maintaining reliability when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes the operational parameters of the air filter by adjusting its position and configuration based on flight phase and environmental conditions. The filter's effectiveness and flow resistance are dynamically adjusted to match the contamination level of the air, reducing performance penalty during clean air operation while maintaining protection during dusty conditions.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If an air filter is used during takeoff and landing to filter air, then engine wear from impurities is reduced, but the filter causes load losses that negatively impact engine performance

Engineering Contradiction:
Improveengine wear from impuritiesVSAvoidload losses
Core Design Contradiction:
Object-affected harmful factorsVSLoss of energy

Solution Approach 1:

The air filter system is designed to dynamically adjust its filtering action based on flight phase. During takeoff and landing when the helicopter operates close to the ground where impurities are present, the filter is activated to protect the engine. During cruise flight at high altitudes where air is naturally clean, the filter is bypassed or reconfigured to minimize load losses and energy consumption, thus reducing the negative impact on engine performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The harmful filtering action is extracted and applied only when necessary. The system separates the filtering function from continuous operation, activating it only during phases where impurities are present (takeoff and landing near ground level), and removing or bypassing it during high-altitude cruise where air quality is good, thereby eliminating unnecessary energy losses.

Inventive Principle:
Principle #2Taking out (Extraction)

3Productivity

If no air filter is installed to maintain engine performance, then load losses are minimized, but foreign bodies enter the combustion chamber causing increased engine wear and higher maintenance costs

Engineering Contradiction:
Improveengine performanceVSAvoidengine wear from foreign bodies
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

Rather than installing a permanent filter that would continuously degrade performance, the system employs a dynamic filter mechanism that activates only when contamination is detected or during flight phases where impurities are likely present. This allows the engine to operate without filtering resistance during clean air conditions, maintaining peak performance while still providing protection when needed.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The air filter system incorporates sensors and control logic that automatically detect the presence of impurities and activate the filter only when necessary. The system serves itself by monitoring air quality and adjusting filter activation accordingly, eliminating the need for continuous filtering and the associated performance penalty while still protecting the engine from harmful foreign bodies when present.

Inventive Principle:
Principle #25Self-service

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

The system enables safe operation in dusty areas by filtering air when necessary and minimizing performance loss by bypassing the filter at high altitudes, reducing maintenance costs and engine wear, while being easy and cost-effective to manufacture.

Implementation Method 1

an air filter having the function of filtering the air taken in, so as to hold back small-sized impurities

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Implementation Method 2

impurities tend to move downwards due to gravity and, therefore, they can be present in the air only in proximity to the ground

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3121415B1Aircraft engine comprising an intake pipe provided with an air filter with openable bottom and relative air filter
Publication Date: 2018.07.04 BMC SRL
  • EP3121415B1 patent drawingFigure 1~3
  • EP3121415B1 patent drawingFigure 4
  • EP3121415B1 patent drawingFigure 5

AI summary

An engine (2) of an aircraft (1) having a tubular housing (3); and at least one air filter (6), which is arranged in the tubular housing (3), has a tubular shape and has an intake opening (7), which is arranged in correspondence to the intake opening (4) of the tubular housing (3), and a bottom wall (8), which is arranged on the inside of the tubular housing (3); the bottom wall (8) of the air filter (6) has an outlet opening (9); there is provided at least one shutter device (10), which is coupled to the outlet opening (9) of the bottom wall (8) of the air filter (6) and is movable between a closed position, in which it closes the outlet opening (9), and an open position, in which it sets the passage through the outlet opening (9) free; and there is provided an actuator (11), which moves the shutter device (10) between the closed position and the open position.