Braking Device Valve Design for Pressure and Feel Trade-off
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Solution Overview
Problem
Existing vehicle braking systems face challenges in achieving sufficient brake pressure, especially in the presence of air in brake circuits, which affects the braking performance and driver feedback.
Innovation Solution
The braking system incorporates an electrically controllable valve that connects the second partial volume to the brake fluid reservoir, allowing for increased brake pressure in wheel brake cylinders by transferring fluid from the second partial volume to the first brake circuit, and includes a mechanical design that ensures pressure buildup up to a specified limit pressure, enhancing brake actuation feel and pressure in both normal and fallback modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the second partial volume is kept pressurized to increase brake pressure, then braking performance is improved, but the driver experiences poor brake actuation feel and the system cannot operate in fallback mode
Solution Approach 1:
The system dynamically switches between two operational states using an electrically controllable valve: in normal operation, the valve opens to depressurize the second partial volume for good brake actuation feel; in fallback mode, the valve closes to pressurize the second partial volume for improved braking performance. This dynamic state change allows the system to optimize for different operational requirements.
Solution Approach 2:
The system prepares for fallback operation by maintaining the capability to quickly pressurize the second partial volume when needed. The mechanically specified limit pressure is pre-established through the valve device design, allowing immediate pressure buildup without complex control algorithms when switching to fallback mode.
2Ease of operation
If the second partial volume is depressurized to improve brake actuation feel, then driver feedback is improved, but brake pressure in wheel brake cylinders is reduced
Solution Approach 1:
The system dynamically switches between two operational states using an electrically controllable valve: in normal operation, the valve opens to depressurize the second partial volume for good brake actuation feel; in fallback mode, the valve closes to pressurize the second partial volume for improved braking performance. This dynamic state change allows the system to optimize for different operational requirements.
3Reliability
If the electrically controllable valve is added to manage pressure in the second partial volume, then braking performance and fallback mode capability are improved, but device complexity increases
Solution Approach 1:
The system replaces complex electronic control algorithms with a mechanically specified limit pressure approach. The valve device is designed with mechanical elements that automatically establish the limit pressure, reducing the need for complex electronic pressure regulation and simplifying the control system while maintaining fallback mode capability.
4Stress or pressure
If brake fluid is transferred from the second partial volume to the first brake circuit, then brake pressure is increased, but the second partial volume becomes pressurized causing resistance to piston wall shifting
Solution Approach 1:
The system prepares for fallback operation by maintaining the capability to quickly pressurize the second partial volume when needed. The mechanically specified limit pressure is pre-established through the valve device design, allowing immediate pressure buildup without complex control algorithms when switching to fallback mode.
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 solution significantly increases brake pressure in wheel brake cylinders, improves brake actuation feel, and ensures reliable braking performance even in fallback modes or with air presence in the circuits, providing a comfortable and effective stopping experience.
Implementation Method 1
a hydraulic connection between the pressure space and the filling space is intended to be freely switchable
Implementation Method 2
the pressure buildup may be brought about up to the limit pressure mechanically specified in the valve device, by shifting the second piston wall
Data Source
AI summary
The present invention relates to a braking device and to a braking system, each having a master brake cylinder (10) having at least one first pressure chamber (12) that is subdivided or is able to be subdivided at least into a first partial volume (12a) and a second partial volume (12b), which are hydraulically connectable or connected to a brake fluid reservoir (24), a first brake circuit (28) being hydraulically connectable or connected to the first partial volume (12a), and having a valve device (38) that is mechanically designed in such a way that a pressure buildup up to a mechanically specified limit pressure may be brought about in the second partial volume (12b), brake fluid being transferable at least into the first brake circuit (28) via at least one subcomponent (38a) of the valve device (38), and an exceeding of the limit pressure in the second partial volume (12b) being prevented.