Variable Displacement Pump and Accumulator for Hydraulic Power Matching
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Solution Overview
Problem
Conventional hydraulic systems with fixed displacement pumps are often oversized for significant portions of the duty cycle due to varying load requirements, leading to inefficiencies in power generation and consumption.
Innovation Solution
The implementation of a hydraulic system that includes a variable displacement pump and an accumulator, controlled by an electronic control unit, which adjusts fluid flow based on load requirements by charging and discharging the accumulator to match power generation and consumption effectively, thereby reducing throttling power losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a fixed displacement pump is sized to accommodate the maximum load required during the duty cycle, then the system can meet peak load requirements, but the pump is oversized for a significant portion of the duty cycle leading to inefficiencies
Solution Approach 1:
The system employs a variable displacement pump that dynamically adjusts its output based on real-time load requirements. The pump's displacement can be varied through a control system that monitors load conditions, allowing the pump to operate at optimal efficiency across the entire duty cycle rather than being locked at a fixed displacement setting sized for peak loads.
Solution Approach 2:
The invention changes the operating parameters of the pump by introducing variable displacement capability. By adjusting the pump's displacement parameter in response to varying load conditions, the system maintains efficient power generation while minimizing energy losses that would occur with a fixed displacement pump operating in an oversized state for extended periods.
2Adaptability or versatility
If a fixed displacement pump is used, then the system structure is simple, but the pump cannot adapt to varying load requirements leading to oversized operation and inefficiency
Solution Approach 1:
The variable displacement pump introduces dynamic adaptability to the system, allowing it to respond to varying load requirements. The pump's displacement can be adjusted in real-time based on load conditions, providing the necessary adaptability while the control system manages the complexity through automated feedback mechanisms.
Solution Approach 2:
The control system implements feedback mechanisms that monitor load requirements and automatically adjust the pump's displacement accordingly. This feedback loop enables the system to adapt to varying loads efficiently, with the control system managing the increased complexity through automated decision-making based on real-time conditions.
3Power
If an oversized pump is used to meet peak loads, then peak power requirements are satisfied, but smaller motors cannot be used leading to higher costs and reduced efficiency
Solution Approach 1:
The variable displacement pump allows the motor to operate at optimal efficiency points across the entire duty cycle by adjusting pump displacement to match load requirements. During peak loads, the pump displacement increases to meet power demands, while during lower load periods, the displacement decreases allowing the motor to operate in its most efficient range, thereby improving overall energy usage.
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 approach allows for efficient matching of power generation and consumption, reducing throttling power losses and enabling the use of smaller motors, which are less costly and more efficient, while maintaining optimal operating ranges.
Implementation Method 1
The hydraulic systems include at least a variable displacement pump and at least one accumulator to supply fluid to a load section of the system
Data Source
AI summary
A hydraulic drive system for driving a load includes a drive shaft; first and second hydraulic pumps driven by the drive shaft, and a control system that operates the hydraulic drive system in a plurality of modes including: a) a first mode where the second hydraulic pump pumps hydraulic fluid from a supply line to an accumulator; b) a second mode where the second hydraulic pump pumps hydraulic fluid from the accumulator to the supply line; c) a third mode where the second hydraulic pump pumps hydraulic fluid from the supply line to a reservoir; and d) a fourth mode where the second hydraulic pump pumps hydraulic fluid from the reservoir to the supply line. At least the second hydraulic pump is a variable displacement bidirectional pump.