Pneumatic Brake System Electronic Parking Control
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Solution Overview
Problem
Existing electropneumatic vehicle brake systems are complex and costly, requiring an inverting relay valve to engage the parking brake in case of service brake circuit failure, which complicates the design and increases costs.
Innovation Solution
A simplified brake system design that uses pressure sensors and an electronic control unit to modulate compressed air to the spring-actuator part of combination spring-actuated/diaphragm cylinders, eliminating the need for an inverting relay valve by generating control signals for solenoid valves based on measured pressures and braking intent, allowing the parking brake to engage automatically in case of service brake circuit failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an inverting relay valve is used to engage the parking brake in case of service brake circuit failure, then the parking brake can be activated automatically, but the system complexity and cost increase
Solution Approach 1:
The patent replaces the mechanical inverting relay valve system with an electronic control system. Pressure sensors detect brake circuit failures and send signals to an electronic control unit, which then actuates solenoid valves to engage the parking brake. This substitution of mechanical components with electronic systems reduces overall system complexity while maintaining the automatic safety function.
Solution Approach 2:
The electronic control unit serves multiple functions: it monitors brake circuit pressure through sensors, determines failure conditions, controls solenoid valves for parking brake engagement, and can modulate brake pressure based on operator intent. This multi-functional approach eliminates the need for dedicated inverting relay valves while achieving the same safety objective.
2Reliability
If an inverting relay valve is used to engage the parking brake in case of service brake circuit failure, then the parking brake can be activated automatically, but the system cost increases
Solution Approach 1:
The patent replaces expensive mechanical inverting relay valves with more cost-effective electronic components including pressure sensors, an electronic control unit, and solenoid valves. Electronic systems generally have lower manufacturing costs, easier assembly, and reduced maintenance requirements compared to complex mechanical valve systems.
3Device complexity
If pressure sensors and electronic control unit are used to modulate compressed air, then system complexity is reduced, but the ability to automatically engage parking brake on failure must be maintained
Solution Approach 1:
The system employs pressure sensors that continuously monitor brake circuit pressure and provide feedback to the electronic control unit. When pressure drops indicate a circuit failure, the control unit receives this feedback and automatically actuates solenoid valves to engage the parking brake, ensuring the safety function is maintained while using simpler electronic components.
Solution Approach 2:
The electronic control system automatically detects brake circuit failures through pressure sensors and autonomously engages the parking brake without requiring mechanical relay valves. The system serves itself by using electronic intelligence to monitor its own state and activate safety measures, replacing complex mechanical self-actuating valves with simpler electronic automation.
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
The system achieves simplified and cost-effective operation by automatically engaging the parking brake in case of service brake circuit failure, providing adequate braking while reducing system complexity and eliminating the need for an inverting relay valve, with the ability to modulate brake pressure based on the vehicle operator's intent and adapt to different brake forces.
Implementation Method 1
a pressure sensor for measuring the first reservoir pressure is provided for this purpose and is connected to an electronic control unit
Implementation Method 2
This electronic control unit controls a modulator for modulation of the compressed air to the spring-actuator part, so that admission of air to and venting of the spring-actuator part can be achieved
Data Source
AI summary
A pneumatic vehicle brake system includes first and second groups of wheel brakes belonging, respectively, to first and second brake circuits having first and second compressed air storage tanks for providing first and second stored pressures. At least one first circuit brake cylinder is a combined spring-store/diaphragm cylinder with a spring store part for providing a parking brake and a diaphragm part for providing a service brake. If the first circuit fails, the spring store part is deaerated to engage the parking brake. A pressure sensor for measuring the first stored pressure is connected to a control unit that controls a modulator for aerating and deaerating the spring store part. The control unit generates a signal for an electrically actuatable modulator solenoid valve if the value measured by the sensor falls below a minimum value, such that the spring store part can be aerated and deaerated via the valve.