Electrohydraulic Brake Valve Segmentation for Simultaneous Pressure Control
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Solution Overview
Problem
Electromechanical brake systems face limitations in achieving optimal driving dynamics control due to time multiplex operation delays, particularly in scenarios requiring different pressure settings for two wheel brakes, which can lead to suboptimal traction control performance.
Innovation Solution
An electrohydraulic vehicle brake system with an electromechanical actuator, electrically activatable valve arrangements, and a control device that allows for simultaneous pressure reduction and build-up at different wheel brakes through the use of first and second valve arrangements, enabling flexible pressure management during driving dynamics control interventions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If time multiplex operation is used to activate valves individually or in groups, then the system complexity is reduced to a single 2/2-way valve per wheel brake, but delay time occurs for setting different pressures at different wheel brakes
Solution Approach 1:
The valve arrangement is segmented into two independent types: first valve arrangements (2/2-way valves) for pressure build-up and second valve arrangements (3/2-way valves) for pressure reduction. Each wheel brake has its own first valve arrangement, allowing independent simultaneous control of pressure build-up and reduction at different wheels, eliminating the time multiplex delay while maintaining simplified system structure.
2Device complexity
If a single 2/2-way valve per wheel brake is used, then the device complexity is reduced, but the ability to simultaneously reduce pressure at one wheel while building up pressure at another wheel is limited
Solution Approach 1:
The first valve arrangement (2/2-way valve) and second valve arrangement (3/2-way valve) are designed with multi-functionality to handle different pressure control scenarios. The first valve arrangement handles pressure build-up, the second handles pressure reduction, and both can operate simultaneously at different wheel brakes, providing universal adaptability for various driving dynamics control situations including traction control, ABS, and ESP.
3Measurement precision
If time multiplex operation is used for pressure modulation, then the electromechanical actuator can change position precisely in a few milliseconds, but optimal driving dynamics control is not achieved in situations requiring different pressure requirements at different wheel brakes
Solution Approach 1:
The control device acts as an intermediary that coordinates the electromechanical actuator with the first and second valve arrangements. It determines when to activate each valve type based on the specific driving dynamics control scenario, enabling precise position control of the actuator while simultaneously achieving rapid pressure adjustments at different wheel brakes without the delays inherent in time multiplex operation.
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 immediate pressure adjustments at multiple wheel brakes, reducing delays and improving traction control performance, especially in situations where different pressure requirements exist between wheel brakes.
Implementation Method 1
an electromechanical actuator (124) for actuating at least one hydraulic piston (112, 114) in order to set a hydraulic pressure at one or more of a plurality of wheel brakes (RB)
Implementation Method 2
a set of electrically activatable valve arrangements (152, 154, 156, 158, 170, 172). The set of electrically activatable valve arrangements comprises a respective first valve arrangement (152, 154, 156, 158) between a cylinder (110) accommodating the at least one hydraulic piston (112, 114) and each of the plurality of wheel brakes (RB)
Data Source
AI summary
An electrohydraulic vehicle brake system includes an electromechanical actuator for actuating at least one hydraulic piston to build hydraulic pressure at wheel brakes. The brake system provides a set of electrically activatable valve arrangements having a first valve arrangement between a cylinder accommodating the at least one hydraulic piston and each of the wheel brakes, and at least one second valve arrangement 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 which is associated with the same wheel brake as the second valve arrangement. A control device or system activates the first valve arrangements and the electromechanical actuator, in order to build up a hydraulic pressure at at least one of the wheel brakes and via the opened first valve arrangement associated with that wheel brake and to reduce a built-up hydraulic pressure via the opened first valve arrangement. The activation of the first valve arrangements can take place in a time multiplex operation.