Variable Displacement Pump Temperature Control via Bypass Recirculation

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Solution Overview

Problem

Variable displacement pumps exhibit non-linear mechanical efficiencies and increased fluid temperature as output flow decreases, necessitating improved control systems to manage temperature and efficiency effectively.

Innovation Solution

A system comprising a variable displacement pump with a bypass valve and an electromechanical actuator, controlled by a controller that adjusts recirculation flow based on downstream demand and temperature feedback to maintain optimal operating conditions, including a bypass valve that recirculates flow from the outlet line to the inlet line when flow demand drops below a threshold.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If variable displacement pump decreases output flow, then productivity is improved, but temperature rise in fluid increases

Engineering Contradiction:

Improveoutput flowVSAvoidfluid temperature

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The system employs a temperature sensor that continuously monitors fluid temperature and feeds this information back to the controller. The controller then adjusts the bypass valve position and pump displacement accordingly to maintain temperature within acceptable limits while optimizing productivity.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the bypass valve position and pump displacement in real-time based on changing operating conditions and temperature feedback, rather than using fixed settings. This allows the system to optimize both productivity and temperature control under varying load conditions.

Inventive Principle:

Principle #15Dynamics

2Use of energy by moving object

If variable displacement pump decreases output flow, then energy consumption is reduced, but mechanical efficiency deteriorates

Engineering Contradiction:

Improveenergy consumptionVSAvoidmechanical efficiency

Core Design Contradiction:

Use of energy by moving objectVSLoss of energy

Solution Approach 1:

The system changes the operating parameters of the pump by adjusting the bypass valve position and displacement mechanism to maintain optimal mechanical efficiency across different operating conditions. This allows energy consumption to be reduced without proportionally sacrificing mechanical efficiency.

Inventive Principle:

Principle #35Parameter changes

3Temperature

If bypass valve increases recirculation flow, then fluid temperature is controlled, but parasitic horsepower loss increases

Engineering Contradiction:

Improvefluid temperatureVSAvoidparasitic horsepower loss

Core Design Contradiction:

TemperatureVSLoss of energy

Solution Approach 1:

The system applies partial recirculation through the bypass valve rather than full recirculation, providing just enough temperature control to maintain fluid within acceptable temperature ranges while minimizing parasitic horsepower losses associated with excessive recirculation.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentEP4467795A1Active displacement control against temperature target for a variable displacement pump

Publication Date: 2024.11.27 HAMILTON SUNDSTRAND CORP

Figure 1

AI summary

A system includes a variable displacement pump (VDP) (102) in fluid communication with an inlet line and with an outlet line. The VDP (102) includes a variable displacement mechanism. A bypass valve (BPV) includes a BPV inlet in fluid communication with the outlet line, and a BPV outlet in fluid communication with a bypass line that feeds into the inlet line upstream of the VDP (102). An actuator is operatively connected to control the BPV to vary flow from the BPV inlet to the bypass line. An electromechanical actuator (EMA) is operatively connected to actuate the variable displacement mechanism. A temperature sensor is operatively connected to the outlet line to generate sensor output indicative of fluid temperature in the outlet line, wherein the temperature sensor is operatively connected to a controller for active control of the EMA and/or of the actuator based on temperature in the outlet line.