Electrohydraulic Brake Valve Parallel Control
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Solution Overview
Problem
Electromechanical brake systems face limitations in achieving optimal driving dynamics control due to the limitations of electric motors and time multiplex operation, particularly in scenarios requiring differential pressure management across wheel brakes during ABS or ESP interventions.
Innovation Solution
An electrohydraulic vehicle brake system with an electromechanical actuator and a set of electrically activatable valve arrangements, including a first and second valve arrangement in parallel, allows for controlled hydraulic pressure management across wheel brakes, enabling simultaneous pressure reduction and build-up, and independent operation of valve arrangements in time multiplex operations to address differential pressure requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If time multiplex operation is used to control valve arrangements for pressure modulation, then the system can achieve wheel-individual pressure control, but delays occur in pressure reduction and optimal driving dynamics control cannot be achieved in all situations
Solution Approach 1:
The control system is segmented into two independent control paths: a first control device for time multiplex operation and a second control device for direct operation. This segmentation allows different control strategies to be applied simultaneously to different wheel brakes, eliminating the bottleneck of sequential control while maintaining wheel-individual control capability.
Solution Approach 2:
The system dynamically selects between two control modes based on real-time requirements: time multiplex operation for normal pressure modulation and direct operation for urgent pressure reduction. This dynamic adaptation allows the system to optimize between control precision and response speed depending on the driving situation.
2Device complexity
If a single valve arrangement is used between the cylinder and wheel brakes, then the system structure is simplified, but the system cannot achieve simultaneous pressure reduction and build-up across different wheel brakes
Solution Approach 1:
The valve control system is divided into two independent control paths: a first valve arrangement for pressure build-up control and a second valve arrangement for pressure reduction control. This segmentation enables differential pressure management across different wheel brakes by allowing independent control of pressure increase and decrease operations.
Solution Approach 2:
The dual valve arrangement system serves multiple functions: it enables both pressure build-up and pressure reduction operations, supports time multiplex operation for normal control, and provides direct operation mode for emergency pressure reduction. This multi-functionality allows a single valve arrangement system to handle diverse pressure management requirements.
3Measurement precision
If the electric motor changes position in a few milliseconds for precise pressure modulation, then wheel-individual pressure control is achieved, but the system reaches performance limits and optimal driving dynamics control is not possible in all situations
Solution Approach 1:
A second control device acts as an intermediary for direct pressure reduction operation, bypassing the electric motor's position control limitations. This intermediary control path enables rapid pressure reduction without being constrained by the motor's response time, thereby improving system reliability under all operating conditions.
Solution Approach 2:
The system changes the control parameter from position-based control (electric motor displacement) to direct pressure-based control (second valve arrangement operation). This parameter change allows the system to achieve rapid pressure reduction by directly controlling hydraulic flow rather than relying on motor position changes, expanding the system's operational envelope.
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 safety and control by allowing precise hydraulic pressure management, reducing delays in pressure reduction, and enabling simultaneous pressure adjustments across multiple wheel brakes, thereby improving driving dynamics and system safety.
Implementation Method 1
an electromechanical actuator (124) for actuating at least one hydraulic piston (112, 114) in order to set a hydraulic pressure in a cylinder (110)
Implementation Method 2
open one of the first valve arrangements (152, 154, 156, 158) and the second valve arrangement (170, 172) connected in parallel therewith, in order to release, via the two opened valve arrangements (152, 170, 154, 172, 156, 172, 158, 172) and into the receptacle device (120), a hydraulic pressure built up in the cylinder (110)
Data Source
AI summary
An electrohydraulic brake system includes an electromechanical actuator for actuating at least one hydraulic piston to provide a hydraulic pressure at one or more of a plurality of wheel brakes. The brake system further includes electrically activatable valve arrangements having a first valve arrangement between a cylinder accommodating the at least one hydraulic piston and each of the plurality of wheel brakes, and at least one second valve arrangement. The second valve arrangement is provided between a receptacle device for hydraulic fluid and at least one of the wheel brakes. The second valve arrangement is provided in parallel with the first valve arrangement associated with the same wheel brake as the second valve arrangement. The brake system also includes a control device or system that opens one of the first valve arrangements and the second valve arrangement connected in parallel therewith, in order to release a hydraulic pressure built up in the cylinder.