Multi-Axle Suspension Load Transfer Control During Hard Braking
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Solution Overview
Problem
In multi-axle suspension systems, dynamic load transfer during hard braking events leads to reduced brake effectiveness as the dynamically unloaded axle fails to contribute significantly to braking effort due to adhesion limits caused by reduced loading, resulting in excessive axle cycling and suboptimal braking performance.
Innovation Solution
A method and system that identify a preset hard brake threshold and detect hard brake events to limit load transfer between axles by sending commands to wheel suspension control components, such as pneumatic or electro-pneumatic valves, to maintain suspension pressure or increase shock dampening on dynamically unloaded axles, preventing load transfer to more loaded axles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If dynamic load transfer is allowed during hard braking, then the more loaded axle can handle increased braking force, but the dynamically unloaded axle loses braking effectiveness due to reduced loading and adhesion limits
Solution Approach 1:
The patent segments the suspension system by introducing separate control valves for each axle in a multi-axle configuration. This allows independent control of suspension pressure at each axle, preventing automatic load transfer from the unloaded axle to the loaded axle during hard braking. Each axle's suspension pressure is managed independently to maintain optimal braking conditions at all axles simultaneously.
Solution Approach 2:
The system dynamically changes suspension pressure parameters during hard braking events. When a hard brake condition is detected, the control system adjusts suspension pressure to prevent load transfer, thereby changing the load distribution parameters across axles. This maintains adhesion conditions and braking effectiveness at each axle by preventing excessive load transfer that would reduce the unloaded axle's contribution to braking.
2Reliability
If load transfer is prevented during hard braking, then braking power is maintained at all axles, but additional control components and complexity are required
Solution Approach 1:
The control system integrates multiple functions into a unified suspension control architecture. The same control valves and electronic control unit that manage normal suspension operations are extended to also handle hard brake load transfer prevention. This multi-functionality approach avoids adding entirely separate systems while achieving the additional control capability needed to maintain braking performance during hard braking events.
Solution Approach 2:
The system uses the existing suspension control infrastructure to automatically detect and respond to hard braking conditions. The control unit monitors braking status and autonomously adjusts suspension pressure distribution without requiring external intervention or complex additional control mechanisms. The existing suspension system serves itself by adapting its behavior based on detected operating conditions.
Data Source
AI summary
When a vehicle decelerates quickly or otherwise experiences a hard brake event, the described systems and methods facilitate reducing load transfer between axles of a common set of axles (e.g. a tandem axle, a tridem axle, etc.). Transfer of suspension pressure from a dynamically unloaded axle to a more loaded axle is limited by a suspension control component such as a valve or solenoid or the like that closes upon detection of a hard brake event in order to lock air in the suspension components of the respective axles. This in turn limits the dynamically unloaded axle from lifting, thereby permitting it to contribute more significantly to the braking effort and improving stopping distance.