Air Spring Pressure Control via Valve Timing
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Solution Overview
Problem
Conventional fluid suspension systems face challenges with accurate height control due to the cost and complexity of height sensors, which are prone to damage in aggressive under-vehicle environments, and pressure-based systems struggle with reliability and installation time, especially when dealing with varying vehicle loads and suspension characteristics.
Innovation Solution
A control system that maps the correlation between air spring pressure changes and valve-open-time to predict and achieve target pressures without height sensors, using a valve, pressure sensor, and control circuitry to iteratively adjust air spring pressure, allowing for open-loop control and user customization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If height sensors are used for accurate closed-loop control of suspension height, then height control precision is improved, but device complexity and installation cost increase
Solution Approach 1:
The patent removes height sensors from the system entirely, extracting only the necessary measurement function through pressure sensing. By measuring air spring pressure instead of directly measuring height, the system achieves height control capability without the complexity and cost of height sensors, while avoiding their vulnerability to damage in under-vehicle environments
Solution Approach 2:
The patent introduces air spring pressure as an intermediary measurement parameter between the control system and suspension height. Instead of directly measuring height with sensors in the under-vehicle environment, the system measures pressure at a protected location and uses this as a proxy to infer and control suspension height, thereby protecting the measurement system from harsh environmental conditions
2Adaptability or versatility
If height sensors are installed on vehicles not designed for them, then height control capability is achieved, but installation time increases
Solution Approach 1:
The patent creates a universal control system that can be installed on various vehicle types without custom modifications. By using the existing air spring pressure system and replacing only the control module and pressure sensor, the system achieves adaptability across different vehicles without requiring vehicle-specific height sensor mounting locations or custom bracket fabrication
Solution Approach 2:
The patent removes the need for vehicle-specific height sensor installation infrastructure. By eliminating height sensors and utilizing the existing air spring pressure system, the invention extracts away the installation complexity associated with mounting height sensors on vehicles not originally designed for them, reducing installation to a straightforward component replacement
3Ease of manufacture
If in-line pressure sensors are used for cost-effective pressure measurement, then installation ease is improved, but measurement accuracy deteriorates due to dramatic pressure changes
Solution Approach 1:
The patent uses air spring pressure as an intermediary that correlates to suspension height through the vehicle loading conditions. By measuring pressure in the air spring rather than at the manifold, the system obtains measurements that directly reflect the suspension state without the dramatic pressure fluctuations experienced at the air supply interface, thereby maintaining measurement accuracy while keeping the sensor installation simple
Solution Approach 2:
The patent implements feedback control where the measured air spring pressure is continuously monitored and used to adjust valve operation. The system opens the valve for a predicted time based on the pressure difference between current and target states, then measures the resulting pressure change. This feedback loop allows the system to adapt to varying vehicle loads and suspension characteristics, maintaining measurement accuracy across different operating conditions
4Device complexity
If conventional pressure-based systems are used without knowing correlation between pressure and height, then system simplicity is maintained, but height control accuracy deteriorates under varying loads
Solution Approach 1:
The patent performs preliminary characterization of the vehicle suspension system by mapping the correlation between air spring pressure and suspension height under specific vehicle loading conditions. This pre-established relationship is stored and used during normal operation to translate pressure measurements into accurate height control predictions, enabling precise height control without adding complexity to the real-time control algorithm
Solution Approach 2:
The patent changes the control parameter from direct height measurement to air spring pressure measurement, which correlates to height through the vehicle loading conditions. By establishing and utilizing the pressure-height correlation for the specific vehicle configuration, the system achieves accurate height control while maintaining simplicity, as pressure sensors are easier to install and more reliable than height sensors
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 reduces installation time and costs, improves system robustness, and effectively maintains target suspension heights by tailoring the control system to the vehicle's specific response characteristics and loading conditions, achieving accurate pressure control within a few iterations.
Implementation Method 1
pressure sensor that senses the fluid pressure of the fluid spring
Implementation Method 2
valve that selectively controls fluid flow to and from the fluid spring
Implementation Method 3
control circuitry that is operatively coupled to the fluid valve and the pressure sensor
Data Source
AI summary
The present invention provides a control system operable to raise and lower the height of a vehicle based in part on the response characteristics of the vehicle's suspension and vehicle loading. The control system may develop a vehicle suspension system response by mapping a correlation between changes in air pressure of air springs in the vehicle's suspension and a test valve-open-time. During operation, the control system may predict a valve-open-time in response to a command relating to a target air pressure for the air springs, and then inflate or deflate one or more of the air springs for a duration substantially equal to the predicted valve-open-time. This process may be iterated until the control system achieves, within an acceptable degree of error, the target air pressure for the one or more air springs.