Electromechanical Lead Screw Pump Control

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Solution Overview

Problem

Electrohydraulic control systems for rotary positive displacement fluid pumps used in gas turbine engines are complex, expensive, and prone to contamination, with limitations in dynamic fuel response and failure modes, particularly in providing fixed fuel flow rates.

Innovation Solution

A variable displacement pump system utilizing an electromechanical controller with a lead screw mechanism to adjust pump displacement, allowing independent control of pump rotor rotation rate and fluid flow, eliminating the need for pressurized fuel and reducing system complexity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If electrohydraulic control systems are used to control pump displacement, then fuel flow control is achieved, but system complexity increases and contamination risks arise

Engineering Contradiction:

Improvefuel flow controlVSAvoidcontrol system complexity

Core Design Contradiction:

Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces the electrohydraulic control system with an electromechanical control system. Specifically, an electric motor drives a lead screw mechanism that directly adjusts the pump displacement, eliminating the need for hydraulic fluid and complex hydraulic components. This substitution reduces system complexity and contamination risks while maintaining fuel flow control capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent extracts and removes the hydraulic fluid system from the control mechanism. By eliminating the hydraulic fluid, hydraulic pumps, and associated hydraulic components, the system achieves simpler architecture and reduced contamination pathways while preserving the essential function of pump displacement control.

Inventive Principle:

Principle #2Taking out (Extraction)

2Force

If pressurized fuel is used in electrohydraulic control systems, then actuation force is provided, but contamination and system complexity increase

Engineering Contradiction:

Improveactuation forceVSAvoidcontamination

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the pressurized fuel actuation system with an electromechanical actuation system. An electric motor directly drives the lead screw mechanism, providing the necessary actuation force without requiring pressurized fuel. This eliminates contamination risks associated with hydraulic fluid while maintaining adequate actuation force for pump displacement control.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Productivity

If variable displacement control is implemented, then fuel flow rate is optimized, but system complexity and cost increase

Engineering Contradiction:

Improvefuel flow rate optimizationVSAvoidcontrol system complexity

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The patent implements variable displacement control through a simplified electromechanical system. An electric motor coupled with a lead screw mechanism provides direct and precise control of pump displacement, enabling fuel flow rate optimization without the complexity of traditional hydraulic control systems. The system achieves productivity optimization with reduced complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

4Measurement precision

If elaborate hydraulic pump control systems are used, then precise fuel flow control is achieved, but system cost and complexity increase

Engineering Contradiction:

Improvefuel flow control precisionVSAvoidcontrol system complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent achieves precise fuel flow control through an electromechanical system that replaces complex hydraulic controls. The electric motor with lead screw mechanism provides precise, controllable adjustment of pump displacement, delivering measurement precision equivalent to or better than hydraulic systems while significantly reducing overall system complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 solution simplifies the control system, reduces contamination risks, and maintains fuel flow stability during power outages by using an electromechanical controller to adjust the lead screw position, ensuring consistent fuel delivery without the need for pressurized fuel, thus addressing the limitations of electrohydraulic systems.

Implementation Method 1

A movable lead screw is coupled to the displacement selection controller so as to be capable of altering the position thereof as a result of selected motions of the lead screw

Methodology Applied

Scientific EffectScrew mechanism: Screw

Data Source

PatentUS8128386B2Variable flow pumping system

Publication Date: 2012.03.06 HAMILTON SUNDSTRAND CORP

AI summary

A variable displacement pump and pump control system therefor to pump a fluid at selected pump output flow rates having a variable displacement pump and a fluid volume displacement selection controller to select a volume of fluid to be forced from the pump inlet to the pump outlet by the rotating member during a rotation thereof. A movable lead screw is coupled to the displacement selection controller so as to be capable of altering the position thereof, and a lead screw positioner is provided for selectively moving, or preventing the moving of, the movable lead screw by extending and retracting the lead screw through a threaded opening.