Secondary Steering Pump Fault Detection via Bypass Valve Testing
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Solution Overview
Problem
Existing methods for testing the operability of secondary steering systems, particularly ground-driven systems, lack comprehensive diagnostic approaches to ensure they function when needed, especially in larger vehicles or work machines where electrically powered systems are insufficient.
Innovation Solution
A secondary steering pump system with a solenoid valve and pressure sensor is employed to selectively actuate a bypass valve, allowing fluid communication between a secondary steering pump and a steering control circuit during testing, while monitoring pressure to confirm operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow switch is used to detect fluid flow in the secondary steering system, then an electrical signal indicating fluid flow presence is provided, but comprehensive diagnostic capability is limited
Solution Approach 1:
A bypass valve is introduced as an intermediary component that can redirect fluid flow from the secondary steering pump to the hydraulic tank. This allows the system to isolate and test the secondary pump's functionality independently by controlling whether its output goes to the steering control circuit or bypasses to the tank, enabling more comprehensive diagnostic capability beyond simple flow detection
Solution Approach 2:
The system implements feedback by monitoring fluid flow through the bypass valve and using this information to determine the operability status of the secondary steering pump. The bypass valve's position and the resulting fluid flow patterns provide feedback signals that indicate whether the secondary pump is functioning correctly, enabling comprehensive diagnostic assessment
2Ease of operation
If the secondary steering system is tested by placing the machine in neutral with the engine off and coasting, then steering operability can be verified, but diagnostic precision and reliability are insufficient
Solution Approach 1:
The bypass valve is configured to preliminarily redirect fluid flow away from the steering control circuit during normal operation, isolating the secondary pump's test function from the primary steering function. This preliminary arrangement of fluid paths allows the secondary pump to be tested independently under controlled conditions, improving both ease of operation and reliability of fault detection
Solution Approach 2:
The testing function for the secondary steering pump is extracted as a separate, independent operation using the bypass valve. Instead of relying on complex machine conditions (neutral, engine off, coasting), the bypass valve enables the secondary pump to be tested in isolation by simply directing its fluid flow to the tank, making the test easier to perform while improving reliability through dedicated test infrastructure
3Power
If electrically powered secondary steering systems are used for smaller vehicles, then steering assistance is provided, but sufficient power is not available for larger vehicles or work machines
Solution Approach 1:
The secondary steering pump is designed with multi-functionality, serving both as a power source for larger vehicles/work machines and as a testable component through the bypass valve mechanism. The bypass valve enables this powerful ground-driven pump to be integrated into the steering system while maintaining the ability to independently test and diagnose its functionality, resolving the conflict between providing sufficient power and managing device complexity
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
Ensures reliable detection of faults in secondary steering systems by verifying the secondary pump's functionality, ensuring it can seamlessly take over in case of primary pump failure, thereby enhancing safety and compliance with regulatory requirements.
Implementation Method 1
a solenoid valve configured for actuation by a solenoid and for selectively actuating the bypass valve from the first position to the second position
Implementation Method 2
a pressure sensor configured for sensing pressure in the system
Data Source
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AI summary
A secondary steering pump system (100) includes a secondary steering pump (108), a bypass valve (110) having a first bypass position (126) configured for placing the secondary steering pump (108) in fluid communication with a hydraulic tank (104) and a second use/testing position (128) configured for placing the secondary steering pump (108) in fluid communication with a steering control circuit (106). The system also includes a solenoid valve (112) configured for actuation by a solenoid (146) and for selectively actuating the bypass valve (110) from the first position (126) to the second position (128). The system (100) also includes a pressure sensor (114) configured for sensing pressure in the system (100).