Suspension Accumulator Fault Detection Through Pressure Decay
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Solution Overview
Problem
Existing vehicle suspension systems face challenges in minimizing pitch and roll while maintaining ride comfort, particularly due to issues with mechanical stabilizer bars and hydraulic accumulator pressure control.
Innovation Solution
An accumulator checking system that includes a state module, valve control module, pump control module, and diagnosis module to accurately set and diagnose the state of accumulator pressures in a vehicle suspension system, using an electric pump to increase pressure and record pressure derivatives to diagnose faults.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If hydraulic accumulators are used to minimize pitch and roll, then suspension stability is improved, but ride comfort deteriorates due to transmission of bump forces across the hydraulic circuit
Solution Approach 1:
The hydraulic circuit is segmented into separate circuits for different suspension components. Accumulators are integrated into individual damper assemblies rather than being part of a shared hydraulic circuit, preventing bump force transmission while maintaining stability control capability.
Solution Approach 2:
The accumulator function is extracted from the main hydraulic circuit and integrated directly into individual damper assemblies. This separation allows the accumulator to minimize pitch and roll locally without transmitting bump forces across the entire suspension system through hydraulic fluid.
2Reliability
If mechanical stabilizer bars are used to counteract roll moments, then cornering performance is improved, but packaging constraints are increased due to requirement for straight unobstructed path
Solution Approach 1:
Mechanical stabilizer bars are replaced with hydraulic accumulators integrated into the damper assemblies. The hydraulic system provides roll moment counteraction through fluid pressure changes without requiring the straight unobstructed mechanical path that stabilizer bars need, thus improving packaging flexibility.
3Device complexity
If hydraulic accumulators are used to replace mechanical stabilizer bars, then device complexity is reduced, but measurement precision deteriorates making it difficult to diagnose accumulator faults
Solution Approach 1:
Pressure sensors are integrated into the hydraulic circuit to provide real-time feedback on accumulator pressure. The control system monitors pressure changes and uses this feedback to diagnose accumulator faults accurately, maintaining measurement precision while keeping the hydraulic system relatively simple.
Solution Approach 2:
Pressure sensors act as intermediary devices between the hydraulic accumulators and the diagnostic system. These sensors provide measurable signals that enable accurate fault diagnosis without requiring complex direct observation of accumulator internal states.
4Ease of manufacture
If accumulators are filled with predetermined fluid amounts based on design considerations, then manufacturing ease is improved, but reliability deteriorates when accumulator pressures become improper
Solution Approach 1:
The system includes self-diagnostic capabilities that allow accumulators to monitor their own pressure levels and alert the system when fluid amounts become improper. This maintains the simplicity of predetermined fluid filling during manufacturing while ensuring reliability through ongoing automatic monitoring and warning.
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 effectively diagnoses accumulator faults and ensures accurate pressure control, enhancing ride comfort and stability by minimizing unwanted suspension movements and maintaining optimal suspension performance.
Implementation Method 1
increase a pressure of hydraulic fluid in a first portion of the suspension system including an accumulator
Data Source
AI summary
A system includes: a state module configured to selectively set a present state to a first state; a valve control module configured to determine first target open and closed states for valves of a suspension system based on the present state and to open and close the valves of the suspension system according to the first target open and closed states, respectively; a pump control module configured to, when the valves are in the first target open and closed states, respectively, selectively operate an electric pump of the suspension system in a first direction and increase a pressure of hydraulic fluid in a first portion of the suspension system including an accumulator, where the valve control module is configured to decrease the pressure in the first portion after the increase; and a diagnosis module configured to selectively diagnose a fault in the accumulator based on a pressure during the decrease.