Redundant Brake Pressure Supply Unit for Fallback Operation
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Solution Overview
Problem
In hydraulic vehicle brake systems, failure of the electrically controllable pressure supply unit requires drivers to exert large brake pedal forces for sufficient service brake deceleration, making it uncomfortable and inefficient.
Innovation Solution
A second electrically controllable pressure supply unit is integrated between the brake master cylinder's pressure chambers and the brake circuit, allowing for pressure boosting to reduce the driver's effort, with independent control and energy supply to maintain functionality even in fallback modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrically controllable pressure supply unit fails, then the brake system can still operate in fallback mode, but large brake pedal forces are required to achieve sufficient deceleration
Solution Approach 1:
The second pressure supply unit is pre-positioned in the hydraulic circuit between the brake master cylinder and the brake circuit, ready to provide pressure boosting when the primary unit fails. This preliminary arrangement ensures that when failure occurs, the redundant unit can immediately compensate without requiring system reconfiguration, thus maintaining ease of operation while ensuring reliability
Solution Approach 2:
The patent implements a redundant pressure supply unit that acts as a cushion against the adverse effects of primary unit failure. This beforehand cushioning ensures that when the primary pressure supply unit fails, the second unit can compensate for the loss of pressure boosting capability, preventing the worsening of brake pedal force requirements and maintaining comfortable operation
2Ease of operation
If a second pressure supply unit is added to the brake system, then pressure boosting capability is improved for comfortable braking, but device complexity increases
Solution Approach 1:
The second pressure supply unit is integrated into the existing hydraulic circuit architecture, merging its functionality with the primary unit's circuit path. Both units share common hydraulic connections to the brake master cylinder and brake circuit, allowing pressure boosting capability to be enhanced without creating entirely separate systems, thus limiting the increase in device complexity
Solution Approach 2:
The second pressure supply unit is designed with multi-functionality, serving as a redundant backup that can operate independently when the primary unit fails, while also being capable of operating in conjunction with the primary unit during normal conditions. This universal design allows a single component to fulfill multiple roles, reducing the need for additional specialized components and limiting 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
Enables comfortable and efficient service brake deceleration with reduced brake pedal force, ensuring sufficient braking performance even in the event of primary pressure supply unit failure, by providing a redundant pressure boosting mechanism.
Implementation Method 1
Hydraulic vehicle brake systems are known which are configured to be operable by external force and which include, in addition to a brake master cylinder actuable by muscle power to which wheel brakes are connected hydraulically
Data Source
AI summary
A motor vehicle brake system and method operable in a brake by wire and in a fallback operating mode. In addition to a first pressure supply unit a second electrically controllable pressure supply unit having at least one intake port and one pressure port, the intake port of which is connected or connectable to one of the pressure chambers and the pressure port of which is connectable or connected to the brake circuit associated with the pressure chamber. The second pressure supply unit is arranged in the hydraulic connection between one of the pressure chambers of the brake master cylinder and the brake circuit associated with the pressure chamber.