Dynamic Brake Factor Estimation for Tractor-Trailer Balance
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Solution Overview
Problem
Existing brake systems in vehicle combinations, such as commercial trucks and trailers, face challenges in maintaining optimal brake balance due to the assumption of a constant brake factor, which can lead to inefficient brake pressure distribution and increased wear, especially under varying operating conditions like different velocities and brake pad temperatures.
Innovation Solution
A method and arrangement that dynamically measures and estimates the brake factor for each wheel axle by determining brake pressure and torque during controlled braking maneuvers, allowing for continuous updates and improved brake adaptation functions to distribute brake pressure optimally between the tractor and trailer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant brake factor is assumed for brake pressure distribution, then the brake system is simple to operate, but brake balance deteriorates under varying operating conditions
Solution Approach 1:
The brake factor is transformed from a static constant value to a dynamic parameter that varies with operating conditions. The control unit continuously adjusts the brake factor based on measured brake pad temperature and vehicle velocity, enabling the brake system to adapt to changing conditions and maintain optimal brake balance between tractor and trailer.
Solution Approach 2:
A feedback mechanism is implemented where the control unit measures actual brake pad temperature and vehicle velocity, calculates the corresponding brake factor, and uses this information to adjust brake pressure distribution. This closed-loop feedback ensures reliable brake balance while accounting for varying operating conditions.
2Force
If brake pressure is increased on the tractor to compensate for poor brake balance, then the braking force is sufficient, but brake wear increases and brakes become too warm
Solution Approach 1:
The brake factor is changed as a function of brake pad temperature and vehicle velocity. When brakes become warm, the brake factor is automatically adjusted to reduce brake pressure, preventing excessive temperature rise and wear. This parameter change maintains sufficient braking force while protecting the brakes from overheating.
3Reliability
If the brake factor is updated continuously based on operating conditions, then brake compatibility improves, but the device complexity increases
Solution Approach 1:
The control unit automatically performs all necessary measurements, calculations, and adjustments without requiring external intervention. The system self-regulates the brake factor based on its own sensors and internal processing, improving brake compatibility while avoiding the need for additional complex external control systems.
Solution Approach 2:
The control unit integrates multiple functions: measuring brake pad temperature, measuring vehicle velocity, calculating the brake factor, and adjusting brake pressure distribution. This multi-functional approach improves brake compatibility without requiring separate dedicated systems for each function, thereby limiting the increase in device complexity.
Data Source
AI summary
The invention relates to a method for measuring and estimating a brake factor in a vehicle brake system, said vehicle including a towing vehicle and a trailer having a plurality of wheel axles, wherein said method includes: initiating a controlled braking manoeuvre involving at least a first wheel axle and a second wheel axle; and obtaining values representing said brake factor for said wheel first wheel axle and said second wheel axle by a control unit which is provided with a brake adaptation function to obtain a brake balance between said towing vehicle and said trailer. The method furthermore includes: braking, in a forced manner, said first wheel axle when retardation of said vehicle is requested; estimating the brake factor for said first wheel axle by determining the brake pressure and braking torque for said first wheel axle; providing a transition phase after which said second wheel axle is braked, in a forced manner, and estimating the brake factor for said second wheel axle by determining the brake pressure and braking torque for said second wheel axle. An arrangement for measuring and estimating the brake factor in a vehicle brake system is also disclosed.