Steering Isolation Valve Pressure Diagnostics Without Wheel Movement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electro-hydraulic steering systems in work machines face challenges in real-time fault detection of isolation valves, often requiring undesirable conditions like wheel movement during startup, which can compromise safety and lead to undetected failures.
Innovation Solution
A method using an integrated diagnostic pressure signal and pressure sensor to detect the functional state of the isolation valve, eliminating the need for wheel movement and providing direct measurement of isolation functionality, thereby enhancing diagnostic coverage and safety integrity levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wheel movement verification is used to detect isolation valve state, then the system can verify steering functionality, but it requires undesirable conditions during startup and may compromise safety
Solution Approach 1:
The patent replaces the mechanical verification method (requiring wheel movement) with a pressure-based sensing system. A pressure sensor monitors pressure differential across the isolation valve to determine its state, eliminating the need for mechanical steering movement during startup while maintaining detection reliability.
Solution Approach 2:
The patent introduces a pressure sensor as an intermediary element that indirectly measures the isolation valve state through pressure differential detection. This intermediary provides a non-intrusive measurement method that does not require actuating the steering system, thus simplifying startup operations while ensuring safety.
2Reliability
If proxy verification of flow downstream from isolation spool is used, then the isolation function can be checked, but it requires wheel movement and increases system complexity
Solution Approach 1:
The patent extracts the detection function from the complex proxy verification system and implements it directly at the isolation valve through a pressure sensor. This localized measurement approach eliminates the need for downstream flow verification and wheel movement, reducing overall system complexity while maintaining detection capability.
Solution Approach 2:
The isolation valve system performs self-diagnosis through the pressure sensor that monitors its own state directly. The system serves itself by providing intrinsic feedback about its isolation function without requiring external verification through wheel movement or complex downstream sensing.
3Measurement precision
If spool position sensor is used to detect isolation valve state, then direct measurement is achieved, but it increases device complexity and cost
Solution Approach 1:
The patent uses hydraulic pressure differential as the measurement mechanism instead of a spool position sensor. By monitoring pressure difference across the isolation valve, the system achieves accurate valve state detection using the existing hydraulic medium, avoiding additional mechanical sensing components and reducing complexity.
Solution Approach 2:
The patent changes the measurement parameter from mechanical position (spool position sensor) to pressure differential (pressure sensor). This parameter transformation enables accurate valve state detection using a simpler, more cost-effective sensing approach that leverages the hydraulic system's inherent pressure characteristics.
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 real-time detection of isolation valve failures, increasing the overall safety rating and diagnostic coverage, potentially raising the Performance Level or Safety Integrity Level of the system, by directly determining the valve state without relying on moving parts of the steering system.
Implementation Method 1
A 7-way/2-position isolation valve acts as a blocking valve for flow between the main-stage spool and the cylinder(s). An additional output pressure signal path (diagnostic signal) connects a dedicated diagnostic signal port to tank pressure when in the closed state (not actuated) and to reduced pilot pressure supply when in the open state (actuated).
Data Source
AI summary
A system and method for detecting the functional state of a piloted or direct-operated isolation valve in a hydraulic circuit is presented. In some examples the hydraulic circuit is a steering circuit and the isolation valve provides selective isolation between a hydraulic actuator and one or more metering valves. In some examples, the isolation valve assembly is movable between a first position, in which fluid flow between the metering valve and the actuator is enabled, and a second position, in which fluid flow between the metering valve and the actuator is blocked. When the isolation valve assembly is moved to one of the first and second positions, an inlet port and a pressure sensing port of the isolation valve assembly are placed in fluid communication with each other. When the isolation valve assembly is moved to the other of the first or second position, a second inlet port and the pressure sensing port are placed in fluid communication.