Brake Pedal Force Simulator Using Resilient Element and Compliance Device
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Solution Overview
Problem
Existing brake-by-wire systems in hybrid vehicles require complex and costly electrohydraulic devices for pedal feel simulation, which are not easily controllable and increase maintenance costs when transitioning between brake modes.
Innovation Solution
An automotive braking system utilizing a master cylinder force simulator with a resilient element and an electronically controlled compliance device to simulate the resistive force of a conventional brake system, allowing selective application of resistive force to the brake pedal, and a linear compliance device to decouple the brake pedal from the master cylinder during regenerative braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrohydraulic devices are used for pedal feel simulation, then brake pedal transparency is improved, but device complexity and maintenance cost increase
Solution Approach 1:
The patent extracts the core function of pedal feel simulation from complex electrohydraulic devices and implements it using a simple resilient element (spring) that directly provides the necessary resistive force. This eliminates the need for electrohydraulic coupling devices while maintaining brake pedal transparency through the natural elastic properties of the spring element.
Solution Approach 2:
The patent replaces the electrohydraulic mechanical system with a purely mechanical resilient element system. The electronically controlled compliance device uses electromagnetic actuators to control a mechanical linkage system that couples or decouples the resilient element from the brake pedal, substituting complex fluid-based electrohydraulic control with simpler electromagnetic-mechanical control.
2Reliability
If electrohydraulic devices are used for pedal feel simulation, then brake pedal transparency is improved, but maintenance cost increases
Solution Approach 1:
The patent employs inexpensive resilient elements (springs) and simple electronically controlled compliance devices with electromagnetic actuators instead of costly electrohydraulic components. These simpler mechanical and electromagnetic components are more durable, easier to replace, and significantly reduce maintenance costs while maintaining the necessary brake pedal transparency function.
3Force
If resilient element is always coupled to brake pedal, then resistive force is always present, but pedal effort increases during conventional braking
Solution Approach 1:
The patent implements a dynamic coupling system through the electronically controlled compliance device that can adjust the connection between the resilient element and the brake pedal in real-time. The controller activates or deactivates the compliance device based on braking mode detection, dynamically changing the mechanical configuration to either engage or disengage the resilient element's resistive force as needed.
Solution Approach 2:
The patent extracts the resilient element from constant engagement with the brake pedal and instead couples it selectively through the electronically controlled compliance device. This allows the resistive force to be removed from the system during conventional braking operations, reducing unnecessary pedal effort while maintaining it during regenerative braking for proper pedal feel simulation.
4Reliability
If resilient element provides resistive force during regenerative braking, then pedal feel transparency is improved, but system complexity increases
Solution Approach 1:
The patent introduces an electronically controlled compliance device as an intermediary mechanism between the resilient element and the brake pedal. This compliance device acts as a controllable coupling element that can selectively transmit or block the resistive force from the resilient element to the brake pedal based on the detected braking mode, providing intelligent control without requiring complex electrohydraulic systems.
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 solution provides a simplified and cost-effective means to maintain transparency in brake pedal effort across modes, minimizing pedal effort during conventional braking and eliminating the need for complex electrohydraulic coupling devices.
Implementation Method 1
The resilient body is elastically deformable by the rotating suspension when the pedal is actuated
Data Source
AI summary
A brake-by-wire automotive braking system includes a master cylinder connected to a number of wheel cylinders, with the master cylinder being actuated by a brake pedal assembly operatively connected with a master cylinder force simulator simulating the resistive force/displacement characteristics of the master cylinder itself. An electronically controlled compliance device selectively immobilizes the master cylinder force simulator so that the resistive force provided by the simulator may be applied selectively to the brake pedal. This produces a transparency in the brake pedal's operational feel, notwithstanding the presence or absence of force provided by the master cylinder force simulator.