Redundant EV Brake Pressure Supply for Fault-Tolerant Wheel Control
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Solution Overview
Problem
Existing braking systems for electric vehicles and autonomous driving levels 4 and 5 face challenges in achieving high availability, redundancy, and precise control while minimizing costs and safety concerns, particularly due to issues with hydraulic and electromechanical components like solenoid valves and ball screw drives.
Innovation Solution
A braking system with redundant pressure supply devices, electronic control units, and a closed brake circuit design, utilizing hydraulic and electromechanical brakes, traction motors, and a connection module to ensure fault-tolerant operation, allowing for precise pressure control and redundancy in wheel-specific braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant pressure supply devices and control units are implemented, then system availability and safety are improved, but device complexity and cost increase
Solution Approach 1:
The braking system is divided into multiple independent pressure supply devices (first and second pressure supply devices), each capable of independently supplying pressure to the brake circuits. This segmentation allows the system to maintain functionality even if one pressure supply device fails, thereby improving reliability while managing complexity through modular design
Solution Approach 2:
Different components of the system have different levels of redundancy assigned based on their criticality. The pressure supply devices and control units are configured with specific redundancy patterns (e.g., one active, one standby) rather than uniform redundancy throughout, optimizing the balance between reliability and complexity
2Reliability
If redundant pressure supply devices and control units are implemented, then system availability and safety are improved, but manufacturing cost increases
Solution Approach 1:
The system uses standby copies of critical components (pressure supply devices and control units) that are identical or substantially similar to the active components. These copies are manufactured using the same processes and specifications, ensuring they can seamlessly take over in case of failure, while benefiting from economies of scale in manufacturing identical parts
Solution Approach 2:
The pressure supply devices and control units are designed with universal interfaces and standardized configurations that allow them to serve multiple functions and be interchanged. This multi-functionality reduces the need for specialized custom-manufactured parts, thereby lowering manufacturing costs while maintaining redundancy
3Manufacturing precision
If closed brake circuit design is used, then braking precision and control are improved, but system complexity increases
Solution Approach 1:
The closed brake circuit design replaces traditional mechanical linkage systems with electro-hydraulic actuation. Electronic control units precisely control hydraulic pressure delivery to the brakes, enabling more precise and responsive braking control while reducing the mechanical complexity of linkages and levers
Solution Approach 2:
The closed brake circuit incorporates feedback mechanisms where sensors monitor brake pressure, pedal position, and system state, and this information is fed back to the control units. This feedback enables precise closed-loop control of braking force, improving braking precision while the control software manages the complexity of coordinating multiple sensors and actuators
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 ensures high availability and safety with precise braking control, even in the event of component failures, by using redundant pressure supply and control units, hydraulic and electromechanical brakes, and traction motors, maintaining optimal braking performance and stability.
Implementation Method 1
a first pressure supply device DV1 and a second pressure supply device DV2, which are used to supply pressure to wheel brakes RB1-RB4 of brake circuits BK1 and BK2
Implementation Method 2
The pressure supply devices each have two control and regulating devices DV ECU1 and DV ECU2 and a valve assembly R-HCU, the components of the pressure supply devices DV1 and DV2 being supplied via two vehicle electrical systems or voltage supplies BN1 and BN2
Implementation Method 3
wheel brakes RB1-RB4 of brake circuits BK1 and BK2
Data Source
AI summary
A brake system for a vehicle may include at least two hydraulic brake circuits, each having at least one hydraulically acting wheel brake, at least two pressure supply devices, each of which is driven by an electromotive drive, at least one valve assembly having valves for the wheel-individual adjustment of brake pressures and/or for separating the wheel brakes from, or connecting same to, a pressure supply device, at least one electronic control and regulating unit, one of which is a superordinate central control unit that controls individual control and regulating units of the components of the brake system, as well as at least one additional electric drive motor for at least one axle or wheel of the vehicle. The brake system may use the at least one pressure supply device and/or the at least one electric drive motor for controlling pressure in at least one wheel brake for steering interventions.