Hydraulic Pressure Estimation via Valve Timing
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Solution Overview
Problem
Existing hydraulic fluid working machines face challenges in accurately measuring pressure within the higher pressure fluid gallery due to the high cost, reliability issues, and complexity associated with traditional pressure transducers.
Innovation Solution
A method is developed to estimate the pressure of hydraulic fluid in a fluid working machine by detecting the timing of valve events, specifically the opening or closing of the first valve, which is indicative of the pressure in the higher pressure gallery, allowing for pressure estimation without the need for traditional pressure transducers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pressure transducers are used to measure hydraulic fluid pressure, then measurement accuracy is improved, but cost increases and system reliability decreases
Solution Approach 1:
The patent replaces the mechanical pressure transducer system with an electronic sensing system that detects valve timing events. Instead of using a mechanical sensor that directly contacts the hydraulic fluid, the system uses electronic sensors to detect the timing of valve opening/closing events, which are influenced by pressure differential. This substitution eliminates the need for expensive and unreliable mechanical transducers while maintaining measurement capability through electronic signal analysis.
Solution Approach 2:
The patent introduces valve timing events as an intermediary parameter to indirectly measure pressure. Rather than directly measuring pressure with a transducer, the system uses the timing information from valve operations as a mediator that correlates with pressure differential. This intermediary approach allows pressure inference through existing valve mechanisms without requiring direct pressure sensing components.
2Measurement precision
If pressure transducers are installed in the hydraulic system, then pressure measurement capability is improved, but device complexity and wiring requirements increase
Solution Approach 1:
The patent extracts the pressure measurement function from the hydraulic system by removing the pressure transducer component entirely. Instead of installing a new sensing device in the fluid system, the system extracts timing information from existing valve operations that are already part of the hydraulic control mechanism. This extraction eliminates the need for additional wiring and complex transducer installation while preserving pressure measurement capability.
Solution Approach 2:
The patent makes the existing valve timing detection system serve multiple functions: it continues to control valve operations for hydraulic fluid displacement while simultaneously providing pressure measurement information through the same timing events. This multi-functionality eliminates the need for separate pressure sensing infrastructure, reducing overall system complexity.
3Ease of operation
If pressure transducers are used to measure higher pressure gallery pressure, then control accuracy is improved, but cost and maintenance requirements increase
Solution Approach 1:
The patent replaces expensive, durable pressure transducers with a low-cost electronic timing detection system. The sensing mechanism uses simple electronic sensors that detect valve timing events rather than requiring expensive pressure-sensitive components. This approach significantly reduces manufacturing cost while maintaining adequate control accuracy through the timing information derived from valve operations.
Data Source
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AI summary
A measurement of the pressure of hydraulic fluid in a fluid working machine can be determined from the timing of the movement of valves which selectively seal a working chamber of cyclically varying volume from a fluid gallery. The timing of opening of a low pressure valve, to connect a working chamber to a low pressure fluid gallery, following the closure of a high pressure valve to seal a working chamber can be used to estimate the pressure in the high pressure fluid gallery at the moment of closure of the high pressure valve.