Fluid-Working Machine Valve Arrangement for Zero-Speed Startup
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid-working machines, such as hydraulic or pneumatic motors/pumps, face challenges in initiating a motoring cycle from zero speed due to the reliance on pre-compression and pre-expansion mechanisms, and existing electromagnetic valve assemblies are too slow to actuate quickly enough for efficient operation.
Innovation Solution
A face-seating valve arrangement is introduced between the working chamber and the high-pressure manifold, allowing for two-stage operation at start-up and low speeds, which transitions to single-stage operation as speed increases, enabling efficient energy conversion and bi-directional flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a solenoid-operated poppet valve is used to open against high pressure in a fluid-working machine, then the valve can control fluid flow, but the valve requires 200 to 300 ms to actuate which is too slow for efficient operation
Solution Approach 1:
The valve assembly is segmented into a master valve and an auxiliary valve. The auxiliary valve opens first to equalize pressure, then the master valve opens rapidly. This segmentation allows the system to overcome the slow actuation problem by dividing the opening process into two stages: pressure equalization (auxiliary valve) and rapid flow establishment (master valve).
Solution Approach 2:
The auxiliary valve acts as an intermediary between the control system and the master valve. It mediates the pressure difference that prevents rapid opening of the master valve by first equalizing pressures through a capillary passage, enabling the master valve to open quickly without requiring excessive force against a large pressure differential.
2Ease of operation
If pre-compression and pre-expansion of working chamber contents is used to actuate electromagnetic poppet valves, then the motoring cycle can be initiated, but the machine requires threshold shaft speed already operating which limits use for starting from zero speed
Solution Approach 1:
The auxiliary valve performs preliminary action by equalizing pressure between the high-pressure manifold and the working chamber before the master valve opens. This preliminary pressure equalization removes the barrier that previously required threshold shaft speed to overcome, allowing the system to initiate operation from zero speed without requiring existing kinetic energy.
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
Enables the fluid-working machine to initiate the motoring cycle from a stationary state with modest force, improving startup efficiency and maintaining performance across varying speed conditions.
Implementation Method 1
a solenoid actuator 23 which generates an electromagnetic force to move the auxiliary valve element
Implementation Method 2
a main spring 33 which exerts a force to move the main valve element into an open position
Implementation Method 3
The nature of poppet valves is that the fluid pressure acts over the seating area creating a large closing force
Data Source
AI summary
In a fluid-working machine having a high-pressure line and a working chamber, a valve arrangement is arranged to control fluid flow from the high-pressure line to the working chamber. The valve arrangement comprises a main valve having a valve element arranged to provide sealing contact with a valve seat, and an auxiliary valve comprising an electromagnetically-movable valve member for equalising pressure on either side of the main valve by placing the working chamber in direct fluid communication with the high-pressure line. The electromagnetically-movable valve member may comprise a spool valve member or a poppet valve member.