Compressed Air Brake System Smooth Transition Control
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Solution Overview
Problem
State-of-the-art compressed air brake systems experience sudden changes in braking behavior when switching from driver braking to driver assistance braking, leading to discomfort due to abrupt changes in brake pressure.
Innovation Solution
A method that combines driver brake pressure and external brake pressure values to create a combined brake pressure value, allowing the system to smoothly transition between driver braking and driver assistance braking modes by actuating the ABS stop valve with system pressure, using a switching device that can switch between base and functional positions based on proportional threshold values to prevent excessive switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switching device is used to switch between driver braking and driver assistance braking modes, then the system can accommodate external braking demands, but sudden changes in brake pressure occur during mode transitions causing discomfort
Solution Approach 1:
The control device determines a combined brake pressure value by combining the driver brake pressure and external brake pressure values before the switching device operates. This preliminary combination of pressure values ensures that when the switching device transitions between modes, the brake pressure changes are predetermined and controlled, preventing sudden pressure changes that would cause discomfort to the driver.
Solution Approach 2:
The control device acts as an intermediary between the switching device and the brake pressure system. It receives both driver brake pressure and external brake pressure values, processes them to determine a combined brake pressure value, and then controls the switching device based on this combined value. This intermediary processing ensures smooth transitions and eliminates abrupt pressure changes during mode switching.
2Ease of operation
If the switching device switches between base and functional positions based on brake pressure values, then the system can modulate brake pressure, but excessive switching may occur leading to instability
Solution Approach 1:
The control device continuously monitors both the driver brake pressure value and external brake pressure value, and uses this feedback to determine the combined brake pressure value. Based on this combined value, the control device controls the switching device position. This feedback mechanism ensures that switching occurs only when necessary and appropriate, preventing excessive switching and maintaining system stability while still enabling effective brake pressure modulation.
3Object-affected harmful factors
If driver brake pressure and external brake pressure are combined, then braking comfort is enhanced, but the system complexity increases
Solution Approach 1:
The control device merges the driver brake pressure value and external brake pressure value to determine a combined brake pressure value. This combining of pressure values allows the system to account for both driver input and external braking demands simultaneously, enhancing braking comfort by providing smooth, coordinated pressure modulation. The merging is performed through control logic that processes both inputs and outputs a unified control signal for the switching device.
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 approach enhances braking comfort by allowing for higher brake pressure modulation while accommodating external braking demands, reducing sudden changes and providing a more responsive braking experience.
Implementation Method 1
The switching device can in particular be implemented as a solenoid 3/2-way valve that is changed over by the ABS control device with a switching signal
Data Source
AI summary
A method for controlling a compressed air brake system of a vehicle includes outputting an analog driver brake pressure via a brake pressure control line during driver braking by operating a brake pedal, a switching device set in a driver braking position to a brake circuit with at least one ABS stop valve device, a brake line, and a wheel brake. The method additionally includes, in the presence of both driver braking and the external brake demand signal, measuring the driver brake pressure and determining a driver brake pressure value. Furthermore, the method includes forming a combined brake pressure value by adding or superimposing the driver brake pressure value and an external brake pressure value contained in the external brake demand signal, and switching the switching device into the functional position and controlling the combined brake pressure value from the system pressure by actuating the ABS stop valve device.