Brake System Secondary Pressure Provision Device
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Solution Overview
Problem
Existing brake systems require significant driver effort and brake pedal force to achieve sufficient service brake deceleration when the electrically controllable pressure provision device fails, leading to an uncomfortable and inefficient braking experience.
Innovation Solution
A secondary electrically controllable pressure provision device is introduced, connected to each brake circuit via a suction connector and pressure connector, which can boost pressure and volume, allowing the driver to apply reduced brake pedal force for sufficient deceleration, and includes an electrically operated adding valve and separating valve configuration to manage hydraulic connections and pressure distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrically controllable pressure provision device fails, then the brake system can still operate in non-boosted fallback mode, but the driver must apply great brake pedal forces to achieve sufficient service brake deceleration
Solution Approach 1:
The brake system is divided into two independent pressure provision devices (first and second electrically controllable devices), each capable of independently providing brake pressure. This segmentation ensures that if one device fails, the other can still provide boosted braking, maintaining both reliability and ease of operation.
Solution Approach 2:
The system incorporates a second electrically controllable pressure provision device as a backup before the primary device fails completely. This redundant device is positioned upstream of the separating valve, ensuring that if the first device fails, the second device can immediately take over to provide pressure boosting, preventing the worst-case scenario of complete loss of power assistance.
2Ease of operation
If a second electrically controllable pressure provision device is added upstream of the separating valve, then brake force boosting is improved in fallback mode, but the device complexity increases
Solution Approach 1:
The second pressure provision device serves multiple functions: it can provide pressure boosting in normal operation, serve as a backup if the first device fails, and work in conjunction with the separating valve to maintain brake circuits in different states. This multi-functionality justifies the added complexity by providing enhanced reliability and performance.
Solution Approach 2:
The separating valve acts as an intermediary element that manages the hydraulic connections between the two pressure provision devices and the brake circuits. By positioning the second pressure provision device upstream of this separating valve, the system creates a controlled interface that manages the complexity while ensuring proper pressure distribution and circuit isolation when needed.
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 configuration enhances the availability of a brake force-boosted operating mode, allowing drivers to achieve sufficient deceleration with less effort by utilizing the secondary pressure provision device, improving comfort and efficiency in fallback operating modes.
Implementation Method 1
the second electrically controllable pressure provision device can suck pressure medium from a pressure space of the brake master cylinder or from a pressure medium container and can feed the pressure medium which is discharged by it into the associated brake circuit or the associated brake circuits
Implementation Method 2
a hydraulic actuating unit 2 which can be actuated by means of an actuating or brake pedal 1, a displacement simulator or simulation device 3 which interacts with the hydraulic actuating unit 2
Data Source
AI summary
A motor vehicle brake system actuated in brake-by-wire and fallback operating modes, having a brake master cylinder, brake circuits, a pressure medium storage vessel, a brake pedal, a separating valve for separating the brake circuit into a first section connected to the separating valve the master cylinder, and a second section connected to the separating valve and the wheel brakes. A first pressure provision device has a piston actuated by an actuator, a simulation device connected by a simulator release valve to the master cylinder for a pleasant brake pedal feel in the brake-by-wire operating mode. A first electronic control and regulating unit actuates the first pressure provision device, the separating valves and the simulator release valve. A second pressure provision device has a suction connector and a pressure connector per brake circuit being connected to the inlet of the separating valve.