Hydraulic Pump Bypass Throttling for Stable Pressure Control
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Solution Overview
Problem
Modern hydraulic systems with fixed displacement pumps and speed and torque controlled electric motors face issues with pressure fluctuations and energy inefficiency when there is a need for pressure without fluid flow, due to internal leakages and uncontrolled pump rotation.
Innovation Solution
Incorporating a by-pass flow channel with a throttle element parallel to the hydraulic pump to direct limited continuous discharge fluid flow back to the reservoir, allowing continuous pump operation and stable pressure control, with the throttle element maintaining low by-pass flow to minimize energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a fixed displacement pump is used with speed and torque controlled electric motor, then pressure control accuracy and energy efficiency are improved, but pressure fluctuations occur when pressure is needed without fluid flow due to internal leakages
Solution Approach 1:
A by-pass flow channel with a throttle element is introduced as an intermediary component. This channel provides a controlled path for fluid to bypass the pump's internal leakage paths, ensuring continuous pump rotation and stable pressure output even when no fluid flow is needed for work. The throttle element mediates the flow to maintain pressure stability without excessive energy consumption.
Solution Approach 2:
The by-pass flow channel ensures continuous useful action by maintaining constant fluid flow through the pump. This continuous flow prevents the pump from stalling or rotating intermittently, which would cause pressure fluctuations. The throttle element regulates this continuous flow to be small enough to minimize energy loss while sufficient to maintain stable pump operation and pressure.
2Stability of the object's composition
If the pump is driven continuously to maintain stable pressure, then pressure fluctuations are avoided, but energy consumption increases due to constant pump rotation
Solution Approach 1:
The by-pass flow channel implements partial action by providing just enough fluid flow to maintain continuous pump rotation and stable pressure, without excessive flow that would waste energy. The throttle element is calibrated to allow only the minimum necessary flow for stability, avoiding the excess energy consumption that would result from full-capacity continuous operation when no work is being performed.
3Stability of the object's composition
If internal leakages in the fixed displacement pump are reduced to improve pressure control, then pressure stability improves, but pump complexity and manufacturing difficulty increase
Solution Approach 1:
Instead of attempting to eliminate internal leakages through complex pump design modifications, the solution extracts the leakage problem from the pump system by providing a separate by-pass flow channel. This channel handles the leakage flow externally, allowing the pump itself to remain simple in design while achieving stable pressure control through the combined system of pump plus by-pass channel.
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 ensures smooth and stable hydraulic system pressure, reduces energy consumption, and adapts to varying flow demands, maintaining efficient operation even at high pressures and low fluid flow conditions.
Implementation Method 1
one or more by-pass flow channels comprising one or more throttle elements for directing limited continuous discharge fluid flow from the hydraulic system
Implementation Method 2
the by-pass flow channel and the continuous by-pass flow through it will provide the system with smooth drive
Data Source
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AI summary
A hydraulic system, working vehicle, and method for producing hydraulic power to a hydraulic system of a working vehicle. The hydraulic system (Hs) comprises a fixed displacement hydraulic pump (Hp) and a speed and torque controlled electric motor (M) for driving the hydraulic pump (Hp). An electric controller (Ec) is arranged to adjust the speed of the electric motor and to thereby adjust produced hydraulic fluid flow and pressure in the system. Further, there is a by-pass flow channel (By) comprising a throttle element (Te) for directing limited continuous discharge fluid flow from the system.