Brake-by-Wire Master Cylinder With Integrated Pedal Feel Feedback
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Solution Overview
Problem
Brake-by-wire systems lack effective feedback mechanisms that mimic the natural braking feel of traditional hydraulic systems, leading to a decoupling of user input from braking output, which can compromise driver confidence and control during braking operations.
Innovation Solution
Incorporating a pedal feel simulator within the master cylinder that uses multiple biasing members, such as springs and elastic pads, to provide proportional feedback to the brake pedal, and utilizing electronically-controlled pressure generating units and two-way valves to manage fluid flow between the master cylinder and wheel cylinders in various operational modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If brake-by-wire system is used to decouple user input from braking output, then automation and safety are improved, but driver feedback and control feel are degraded
Solution Approach 1:
The pedal feel simulator provides force feedback to the driver's pedal input, creating a feedback loop that simulates traditional hydraulic braking feel. The feedback force is proportional to the braking output, allowing the driver to perceive braking intensity while the system operates in automated brake-by-wire mode.
Solution Approach 2:
The pedal feel simulator acts as an intermediary device between the driver's pedal input and the electronic braking system. It translates the driver's mechanical input into proportional force feedback while the electronic pressure generating unit handles the actual braking output, mediating between automated control and driver perception.
2Ease of operation
If pedal feel simulator is incorporated in master cylinder, then driver feedback is improved, but device complexity increases
Solution Approach 1:
The pedal feel simulator is merged with the master cylinder assembly, integrating the feedback mechanism directly into the existing hydraulic component. This combines multiple functions (feedback generation and fluid pressure management) into a single integrated unit, reducing overall system complexity despite adding functionality.
Solution Approach 2:
The master cylinder assembly is designed to perform multiple functions: traditional hydraulic pressure generation and pedal feel simulation. By making the master cylinder multi-functional, the patent avoids adding separate dedicated feedback devices, thereby managing complexity while providing enhanced driver feedback.
3Adaptability or versatility
If two-way valves are used to manage fluid flow in multiple operational modes, then system versatility is improved, but device complexity increases
Solution Approach 1:
The two-way valves are designed to dynamically switch between different operational modes (standard brake-by-wire, back-up, and push-through modes). The valves transition between positions based on system requirements, allowing a single valve structure to manage multiple operational states without requiring separate dedicated valve assemblies for each mode.
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 solution provides a natural and varied pedal feel that simulates direct braking action, enhancing driver feedback and control, while ensuring reliable braking performance through multiple operational modes, including standard brake-by-wire, back-up, and push-through modes.
Implementation Method 1
a pedal feel simulator within the master cylinder that uses multiple biasing members, such as springs and elastic pads, to provide proportional feedback to the brake pedal
Implementation Method 2
multiple biasing members, such as springs and elastic pads
Implementation Method 3
an electronically-controlled pressure generating unit configured to move fluid through the first braking circuit to the wheel cylinder
Implementation Method 4
a two-way valve positioned in the first braking circuit and configured to selectively decouple the master cylinder from the wheel cylinder
Data Source
AI summary
A vehicle braking system includes a master cylinder having a pedal feel simulator incorporated therein, a reservoir configured to retain a volume of unpressurized brake fluid for use in the vehicle braking system, a wheel cylinder coupled to the master cylinder via a first braking circuit, an electronically-controlled pressure generating unit configured to move fluid through the first braking circuit to the wheel cylinder in a first mode of operation, and a two-way valve positioned in the first braking circuit and configured to selectively decouple the master cylinder from the wheel cylinder. In the first mode of operation, the master cylinder is decoupled from the wheel cylinder via the two-way valve and the master cylinder is coupled to the reservoir via the two-way valve. In a second mode of operation, the master cylinder is coupled to the wheel cylinder via the two-way valve.