Variable Displacement Pump Load-Adaptive Control
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Solution Overview
Problem
Hydraulic systems in machines face disruptions due to varying load demands from environmental factors, leading to inefficient power consumption and operation instability.
Innovation Solution
A system comprising a variable displacement pump, an electronic controller, and control valves that adjust displacement based on machine operating parameters, using electro-hydraulic and electronic pressure reducing valves to modulate fluid flow and pressure, thereby de-rating the hydraulic system to optimize power utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the hydraulic system operates at full power rating to meet peak load demands, then the power availability is improved, but the fuel consumption increases and power reserve is reduced
Solution Approach 1:
The hydraulic system implements dynamic power rating adjustment by varying the pump displacement setting in real-time based on actual load conditions. The controller continuously monitors load demands and adjusts the pump displacement to provide only the necessary power, transforming the static full-power operation into a dynamic adaptive system that optimizes power availability while reducing fuel consumption during low-load conditions
Solution Approach 2:
The system changes the operational parameters of the hydraulic pump by adjusting the displacement setting according to actual load requirements. Instead of operating at a fixed maximum displacement, the controller modulates the displacement parameter to match the instantaneous power demand, thereby reducing energy consumption while maintaining adequate power availability when needed
2Power
If the hydraulic system operates at full power rating, then the power reserve is improved, but the fuel consumption increases
Solution Approach 1:
The system dynamically adjusts the pump displacement to maintain adequate power reserve only when load conditions require it. By continuously monitoring actual load demands and adapting the power output accordingly, the system ensures power reserve availability during peak demands while avoiding unnecessary fuel consumption during steady-state or low-load operation
3Use of energy by moving object
If the hydraulic system de-rates to reduce fuel consumption, then the energy efficiency is improved, but the power availability may be reduced
Solution Approach 1:
The hydraulic system incorporates feedback control by continuously monitoring actual load conditions and using this information to adjust the pump displacement setting. The controller receives feedback on power demands and dynamically modifies the power rating to match actual needs, ensuring that power availability is maintained when required while optimizing energy efficiency during normal operation
Solution Approach 2:
The system transitions from static power rating to dynamic power rating adjustment, where the pump displacement is continuously adapted based on real-time load conditions. This dynamic adjustment ensures that power availability is never compromised while maximizing energy efficiency by avoiding excessive power generation during low-demand periods
4Use of energy by moving object
If the pump displacement is frequently adjusted to match load variations, then the energy efficiency is improved, but the system complexity increases
Solution Approach 1:
The system replaces complex mechanical displacement adjustment mechanisms with electronic control. The variable displacement pump is equipped with an electronically controlled displacement setting mechanism that can be adjusted via electrical signals from the controller, eliminating the need for complex mechanical linkages, levers, or manual adjustment devices while achieving the same energy efficiency benefits
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
This solution stabilizes machine operation by reducing load consumption and improving power utilization, leading to decreased fuel consumption and lower costs, while maintaining productivity.
Implementation Method 1
an electro-hydraulic (EH) relief valve is in fluid communication with the control conduit and the drain passage. The EH valve selectively vents fluid from the control conduit into the drain passage in response to a control signal
Implementation Method 2
an electronic pressure reducing valve (EPRV) fluidly communicates with the control conduit, the supply conduit, and the drain passage. The EPRV selectively vents fluid from the supply conduit into a reduced pressure conduit in response to a control signal
Implementation Method 3
The low pressure resolver has a first inlet in fluid communication with the reduced pressure conduit, a second inlet in fluid communication with the control conduit, and an outlet in fluid communication with the control valve. The low pressure resolver fluidly connects the outlet thereof with the first or second inlet depending on their respective pressure
Implementation Method 4
The variable displacement pump receives a torque limit from the engine, is associated with the hydraulic system, and provides an operating fluid flow at a supply pressure to the hydraulic system. The operating fluid flow being is correlated to a load during operation
Data Source
AI summary
A control for a variable displacement pump disposed in a hydraulic system obtains a requested signal from a manual control device and provides a command signal to a valve operating to adjust a displacement setting of the variable displacement pump. The control provides the command signal based on the requested signal, and scales the requested signal based on a sensed or calculated load of the system.