Parking Brake Ventilation Valve for Fault-Tolerant Spring Brake Engagement
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Solution Overview
Problem
Existing electronically controllable pneumatic brake systems in vehicles face challenges in reliably engaging the parking brake without manual intervention, particularly in automated driving scenarios, leading to increased air consumption and potential safety risks.
Innovation Solution
Incorporating a ventilation valve unit connected to a secondary electronic brake control unit to directly ventilate the secondary working connection, reducing reservoir pressure and ensuring the spring brake cylinders engage, even in the event of primary system failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the parking brake is engaged by electronic control without manual intervention, then the ease of operation is improved, but the reliability of parking brake engagement deteriorates due to increased air consumption and potential system failures
Solution Approach 1:
The ventilation valve unit is pre-configured and connected to the secondary working connection, ready to immediately ventilate the spring brake cylinders when activated by the secondary electronic brake control unit, ensuring rapid and reliable parking brake engagement without manual intervention
Solution Approach 2:
The ventilation valve unit acts as an intermediary component between the secondary electronic brake control unit and the spring brake cylinders, enabling automatic control of the parking brake engagement process while managing air consumption in the brake system
2Reliability
If the ventilation valve unit directly ventilates the secondary working connection, then the reliability of parking brake engagement is improved, but the air consumption in the brake system increases
Solution Approach 1:
The ventilation valve unit extracts and releases trapped air from the secondary working connection and spring brake cylinders, enabling the parking brake to engage reliably by removing the compressible air medium that prevents spring force from acting on the brake mechanism
Solution Approach 2:
The system changes the pressure parameter in the brake system by ventilating the secondary working connection, transitioning from a pressurized state that prevents parking brake engagement to a depressurized state that allows reliable spring force actuation
3Extent of automation
If the secondary electronic brake control unit controls the ventilation valve unit, then the extent of automation is improved, but the device complexity increases
Solution Approach 1:
The secondary electronic brake control unit performs multiple functions including controlling the ventilation valve unit for parking brake engagement, managing redundancy brake pressure, and responding to system failures, thereby automating multiple brake system functions through a single control unit
Solution Approach 2:
The ventilation valve unit is integrated with the secondary working connection and controlled by the secondary electronic brake control unit, merging multiple components and control functions into a coordinated system that automates parking brake engagement while managing overall system complexity
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
Ensures reliable and efficient engagement of the parking brake by increasing air consumption in the brake system, maintaining vehicle safety without manual intervention, even in fault conditions.
Implementation Method 1
a first ventilation valve unit arranged downstream of the first secondary working connection and connected to the secondary electronic brake control unit and that is provided to ventilate the first secondary working connection into the surroundings in accordance with at least one first ventilation signal provided by the secondary electronic brake control unit so as to lower the reservoir pressure level
Implementation Method 2
The spring brake cylinders may be combined with service brake cylinders, such that the spring brake and service brake act on the same brake pistons. If the service brakes are actuated while the parking brakes are active, the spring brake cylinders are simultaneously pressurized in order to thus avoid summation of the braking forces.
Data Source
AI summary
An electronically controllable pneumatic brake system has a primary service brake pressure modulator, a primary control unit, a secondary control unit that controls the first service brake circuit in the event of a fault, and a secondary service brake pressure modulator connected to the secondary control unit. The secondary service brake pressure modulator is supplied with reservoir pressure and has a secondary working connection for providing a redundancy brake pressure. A parking brake assembly is supplied with reservoir pressure and provides at a parking brake working connection a parking brake pressure for spring brake cylinders. A ventilation valve unit is arranged downstream of the secondary working connection and is connected to the secondary control unit and ventilates the secondary working connection in accordance with a ventilation signal provided by the secondary control unit so as to lower a reservoir pressure in order thereupon to ventilate the spring brake cylinder.