Hydraulic Steering Valve Redundancy for Dual-Fault Control
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Solution Overview
Problem
Existing hydraulic power steering systems lack sufficient operational safety due to the lack of detailed redundancy in flow control valve arrangements, which can lead to unsafe steering operations if one valve fails, especially when both valves from different arrangements malfunction simultaneously.
Innovation Solution
The system incorporates electrically actuated continuous inlet and outlet valves in each flow control valve arrangement, allowing for the specific deactivation of faulty valves while maintaining operation with the error-free counterpart, ensuring that even if both valves from different arrangements fail, steering can still be maintained safely.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant hydraulic circuits are implemented, then operational safety is improved, but device complexity increases
Solution Approach 1:
The flow control valve assembly is segmented into multiple independently controllable valves (first inlet valve, second inlet valve, first outlet valve, second outlet valve) instead of using a single valve per circuit. This segmentation allows selective deactivation of faulty individual valves while maintaining operation of remaining valves, thereby improving operational safety without requiring complete circuit redundancy
Solution Approach 2:
The patent transitions from circuit-level redundancy to component-level redundancy within the same hydraulic circuit. By adding multiple valves at the component level (inlet and outlet valves in parallel arrangements), the system achieves enhanced fault tolerance without duplicating entire hydraulic circuits, thus improving reliability while controlling device complexity
2Reliability
If complete hydraulic circuit redundancy is implemented, then fault tolerance is improved, but loss of substance increases
Solution Approach 1:
The system segments the flow control function into multiple valves within a single hydraulic circuit, allowing selective isolation of faulty valves rather than deactivating entire circuits. This enables maintenance of steering functionality with minimal hydraulic fluid loss, avoiding the need to drain and replenish fluid in completely redundant circuits when faults occur
Solution Approach 2:
The patent implements partial redundancy by providing multiple inlet and outlet valves rather than complete circuit duplication. This partial action approach provides sufficient fault tolerance for operational safety while minimizing the excess hydraulic fluid that would be required for complete circuit redundancy, achieving an optimal balance between reliability and substance loss
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 enhances operational safety by allowing the system to maintain steering functionality even with dual valve failures, providing structurally simple and effective redundancy, thus preventing dangerous steering movements and ensuring reliable operation without operator intervention.
Implementation Method 1
each flow control valve arrangement (16, 18) has an inlet valve (V1, V4) and an outlet valve (V2, V5), which are assigned to each other in pairs, designed as continuous valves, and can be electrically actuated by means of control signals
Implementation Method 2
control signals, which are compared with each other by means of the fault detection device (30), and in the event of deviations recognized as relevant, lead to the deactivation of at least one valve recognized as faulty
Implementation Method 3
the fault-free components of at least one subsystem can be caused to maintain the control of the steering actuator
Data Source
AI summary
The invention relates to a hydraulic power steering system, at least consisting of a steering actuator (10) that is actuated in opposite steering directions using two sub-systems (12; 14), each of which is provided in the form of a flow regulating valve assembly (16; 18) with a release valve (V3; V6), and a fault detection device (30), by means of which at least one faulty component (V1, V2; V4, V5) of each sub-system (12; 14) can be ascertained and deactivated and by means of which the fault-free components (V1, V2, V3; V4, V5, V6) of at least one sub-system (12; 14) can be triggered so as to keep the steering actuator (10) actuated. The invention is characterized in that each flow regulating valve assembly (16, 18) has a feed (V1; V4) and a discharge valve (V2; V5) which are paired together and are designed as continuous valves (28) and which can be electrically actuated by means of actuation signals, said actuation signals being compared with one another by means of the fault detection device (30), in the event of deviations detected as being relevant, in order to deactivate at least one of the valves (V1, V2, V3; V4, V5, V6) detected as being faulty.