Pilot Pressure Control System for Steer-by-Wire Reliability
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Solution Overview
Problem
Existing pilot pressure control systems in hydraulic control circuits for steer-by-wire systems face reliability issues due to potential malfunctions in solenoid valves, leading to incorrect electronic communication and impaired operation, necessitating additional steering systems for increased reliability.
Innovation Solution
A pilot pressure control system comprising two individually controllable pilot valve assemblies that provide selective fluid flow directions, ensuring the pilot outlet pressure remains above 20% or below 80% of the maximum pressure, allowing the system to maintain control valve operation even if one valve assembly malfunctions, with optional throttling arrangements for optimal pressure management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single solenoid valve is used to control pilot pressure, then the device complexity is low, but the reliability deteriorates due to potential malfunctions
Solution Approach 1:
The pilot pressure control system is divided into two independent pilot valve assemblies (first and second assemblies), each capable of controlling pilot pressure independently. This segmentation allows the system to maintain functionality even if one assembly malfunctions, thereby improving reliability without requiring a complete system redesign
Solution Approach 2:
The system maintains pilot outlet pressure within a specific range (above 20% or below 80% of maximum pressure) through the coordinated operation of two valve assemblies. By controlling pressure parameters through multiple valves, the system achieves higher reliability while managing complexity through parameter-based control
2Reliability
If pilot pressure is controlled to remain above 20% or below 80% of maximum pressure, then the control valve operation reliability is improved, but the pressure control complexity increases
Solution Approach 1:
The system incorporates pressure sensing and control mechanisms that monitor pilot outlet pressure and adjust valve operation accordingly. The feedback control ensures pressure remains within the specified range (above 20% or below 80% of maximum), maintaining reliable control valve operation while managing complexity through automated pressure regulation
Solution Approach 2:
The pilot valve assemblies are individually controllable, allowing dynamic adjustment of pilot pressure based on system requirements. This dynamic control capability enables the system to maintain pressure within the optimal range while adapting to different operating conditions, improving reliability without requiring overly complex fixed-pressure systems
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
The system enhances the reliability of pilot pressure control by ensuring the control valve can change its condition even if one pilot valve assembly malfunctions, without the need for identifying the malfunction and modifying operations, thereby maintaining system functionality.
Implementation Method 1
at least the first pilot valve assembly is adapted to assume a maximum pressure supply condition so as to supply a first pilot valve assembly maximum pressure to the pilot outlet
Implementation Method 2
at least the second pilot valve assembly is adapted to provide a pressure drop from the pilot outlet to the drain line via the second pilot valve assembly
Data Source
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AI summary
The present disclosure relates to a pilot pressure control system (28) for controlling a pilot signal pressure at a pilot inlet (24; 26) of a control valve (22). The pilot pressure control assembly (28) comprises a pilot outlet (36) adapted to be connected to the pilot inlet (24; 26). The pilot pressure control assembly (28) further comprises a first pilot valve assembly (38) and a second pilot valve assembly (40). Each one of the first and second pilot valve assemblies (38, 40) are individually controllable so as to selectively provide a first fluid flow direction from a pressure line (32) to the pilot outlet (36) and a second fluid flow direction from the pilot outlet (36) to a drain line (34). At least the first pilot valve assembly is adapted to assume a maximum pressure supply condition so as to supply a first pilot valve assembly maximum pressure to the pilot outlet. At least the second pilot valve assembly (40) is adapted to provide a pressure drop from the pilot outlet (36) to the drain line (34) via the second pilot valve assembly (40). The pilot pressure control (28) system is configured such that, when the pilot pressure control system is connected to the pressure and drain lines (32, 34) and when the first pilot valve assembly (38) is controlled so as to assume the maximum pressure supply condition and the second pilot valve assembly provides a fluid flow in said second fluid direction with a minimum pressure drop, the pressure at the pilot outlet is equal to or above 20 % of the first pilot valve assembly maximum pressure (Pmax).