Pneumatic Suspension Control System with Merged Axle Circuits
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Solution Overview
Problem
Current control systems for pneumatic suspensions in vehicles with symmetrical load distribution are overly complex and expensive due to the need for multiple sensors and valves to manage load distribution across axles, particularly in vehicles like tractors with semitrailers or tank trucks.
Innovation Solution
A simplified control system using a single load level sensor, a single pressure sensor, and a single solenoid valve per axle, along with an electronic control unit, which leverages symmetry to manage air pressure and distribution, reducing the number of components and costs while maintaining effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple level sensors, pressure sensors, and solenoid valves are installed on each axle to control load distribution, then the control precision and load management capability are improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent merges the pneumatic circuits of left and right suspensions on the same axle into a single shared circuit. Instead of having separate control systems for each side, the invention uses one pressure sensor and one solenoid valve per axle to control both left and right bellows, reducing component count while maintaining load distribution control capability
Solution Approach 2:
The single pressure sensor and solenoid valve per axle serve multiple functions: they control both left and right suspension bellows, detect overall axle load conditions, and manage air distribution across the entire axle. This multi-functional approach eliminates the need for redundant sensors and valves on each side
2Ease of operation
If separate control elements are installed on each suspension to manage load ratio among axles, then the control effectiveness and load distribution accuracy are improved, but the installation cost and component cost increase
Solution Approach 1:
The invention combines the control functions for left and right suspensions into a single integrated control system per axle. The electronic control unit receives signals from one level sensor and one pressure sensor per axle, and controls one solenoid valve per axle that regulates air flow to both left and right bellows, significantly reducing installation requirements
3Reliability
If multiple pressure sensors are installed on both cells of each axle to detect load, then the measurement accuracy and control reliability are improved, but the component cost and system complexity increase
Solution Approach 1:
The patent reduces the number of pressure sensors from two per axle (one for each cell) to a single pressure sensor per axle. The sensor is positioned to detect the overall pressure in the shared pneumatic circuit, which reflects the total load on the axle. This single sensor provides sufficient information for the electronic control unit to manage load distribution reliably
4Measurement precision
If multiple level sensors are installed on each axle to detect wheel load, then the load detection accuracy is improved, but the component cost and installation complexity increase
Solution Approach 1:
The invention reduces level sensor installation from two sensors per axle (left and right sides) to a single level sensor per axle. The sensor is positioned to detect the overall suspension trim of the axle, which reflects the average load condition. This single sensor provides sufficient feedback for the electronic control unit to maintain proper load distribution
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 solution reduces component and installation costs while maintaining the ability to manage load distribution and vehicle stability, particularly on bends, by utilizing fewer sensors and valves, and incorporating narrowings in pneumatic pipes to counterbalance centrifugal forces.
Implementation Method 1
a control system controls the suspension trim and the flow of the compressed fluid (typically air)
Implementation Method 2
controls the solenoid valves which make the air come in or go out through the bellows
Implementation Method 3
incorporating narrowings in pneumatic pipes to counterbalance centrifugal forces
Data Source
Figure 1
AI summary
The present invention relates to a control system for pneumatic suspension of a vehicle with symmetrical load between right and left side on each axle comprising one single level sensor 12, one single pressure sensor 6, 9 for each axle, one single solenoid valve 4, 8 for each axle, and one solenoid valve for the charging and the discharging of air from a compressed air tank 13 by means of solenoid valves 8 and 4 toward the cells 10 and 14 of the bridge and the cells 2 and 5 of the additional axle. When required, the solenoid valve 15 discharges air from the cells in the atmosphere by means of an outlet 16.