Utility Vehicle Brake Redundancy Using Stored Pressure Distribution
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Solution Overview
Problem
In vehicles with pneumatic brake systems, especially utility vehicles, redundancy cases due to electronic service brake system failures lead to instability and axle locking, which existing solutions either increase costs with additional components or compromise comfort with cadence brakes, and current redundancy methods result in unfavorable braking force distribution.
Innovation Solution
A method for automated electronic control of brake systems that reads braking requests, determines and stores brake pressure distributions, and controls redundant front and rear axle brake pressures using a second electronic control unit, ensuring stability by utilizing stored brake pressure distributions and levels even in cases of signal processing failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant wheel revolution rate sensors are used to prevent axle locking in failure cases, then reliability is improved, but device complexity and cost increase
Solution Approach 1:
The second electronic control unit is designed to perform multiple functions: it serves as a backup control unit that can take over braking control when the first control unit fails, and it also stores brake pressure distribution data for use during normal operation. This multi-functionality eliminates the need for additional redundant sensors while maintaining system reliability.
Solution Approach 2:
Instead of adding physical redundant sensors, the system creates a functional copy by having the second control unit store and use brake pressure distribution data that mirrors the information that would be obtained from redundant sensors. This virtual copying approach maintains reliability without increasing physical hardware complexity.
2Reliability
If cadence brake is used to prevent axle locking in redundancy cases, then reliability is improved, but comfort deteriorates
Solution Approach 1:
The system performs preliminary action by storing the brake pressure distribution data before any failure occurs. When the first control unit fails, the second control unit can immediately retrieve and apply the stored distribution data, providing smooth and comfortable braking without the need for cadence brake's pulsating action.
3Reliability
If parking brake device is used for redundancy braking on rear axle, then reliability is improved, but braking force distribution becomes unfavorable
Solution Approach 1:
The system dynamically adjusts the braking force distribution by having the second control unit retrieve and apply the stored brake pressure distribution data, which represents the optimal distribution. This allows the braking system to maintain favorable force distribution during redundancy operation, unlike the static and unfavorable distribution when using only the parking brake device.
Data Source
AI summary
A method for automatic electronic control of a brake system in a vehicle includes reading a brake signal for the automatic electronic control of brakes in the vehicle, wherein requests to be implemented by the brakes are transmitted via the brake signal to bring about automatically requested target vehicle longitudinal dynamics. The method further includes determining a brake pressure distribution indicating a ratio of a front axle brake pressure of a front axle to a rear axle brake pressure of a rear axle, and providing at least a first brake pressure signal of the first electronic control unit to at least a first electropneumatic control device, taking into account the braking request signal and the brake pressure distribution for controlling the front axle brake pressure and the rear axle brake pressure, and receiving the brake pressure distribution at a second electronic control unit and storing the detected brake pressure distribution.