Master Cylinder Dual Piston Pedal Feel Simulation
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Solution Overview
Problem
Combined brake systems that use both electronic and hydraulic brakes without a booster struggle to replicate the pedal feel of traditional hydraulic brake systems, leading to inconsistent driver experience due to the lack of a booster, which affects the gradient and effort required in braking.
Innovation Solution
A master cylinder design with a primary and secondary chamber, interconnected by a hydraulic line, where the first piston is moved by pedal pressure and contacts a second piston at a predetermined interval, providing elastic restoring force and increasing hydraulic pressure transmission area, mimicking the pedal feel of a hydraulic brake system with a booster.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a hydraulic brake system without a booster is used to reduce device complexity and eliminate electric power consumption, then the brake system structure is simplified and energy efficiency is improved, but the pedal feel becomes inconsistent and driver comfort deteriorates
Solution Approach 1:
The master cylinder is divided into two separate chambers: a first chamber with a first piston for initial brake application, and a second chamber with a second piston for enhanced braking force. This segmentation allows each chamber to handle different stages of braking, creating a multi-stage pedal feel that mimics traditional booster systems without requiring complex electronic components
Solution Approach 2:
The patent implements a dynamic pedal feel through the interaction between two pistons with different cross-sectional areas. As the pedal stroke progresses, the hydraulic pressure increases non-linearly due to the area difference between pistons, creating a progressive resistance curve that provides consistent feedback to the driver throughout the braking operation
2Force
If the electronic brake is applied to all vehicle wheels to improve braking performance, then braking force is enhanced, but electric power consumption increases and system reliability decreases due to dependency on electric systems
Solution Approach 1:
The patent employs a purely hydraulic master cylinder design with two chambers and pistons of different cross-sectional areas. This hydraulic mechanism generates progressive braking force through pressure multiplication based on the area ratio between the first and second pistons, eliminating dependency on electric systems while maintaining high braking performance and reliability
3Device complexity
If a single chamber master cylinder is used in a hydraulic brake system without a booster, then the device complexity is reduced, but the pedal feel cannot replicate the gradient characteristics of a booster system
Solution Approach 1:
The master cylinder is segmented into two distinct chambers with different piston cross-sectional areas. The first chamber handles initial pedal stroke with gentler resistance, while the second chamber engages at larger strokes to provide increased hydraulic pressure. This segmentation creates the characteristic gradient pedal feel without requiring a booster mechanism
Solution Approach 2:
Each chamber is designed with specific local characteristics: the first chamber has a smaller piston area for initial soft engagement, while the second chamber has a larger piston area for enhanced pressure generation at higher strokes. This local differentiation of chamber properties creates the desired progressive pedal feel throughout the braking 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 design achieves a pedal feel similar to that of a hydraulic brake system using a booster, reducing driver discomfort by gradually increasing pedal effort, and ensuring a consistent braking experience without the need for a booster.
Implementation Method 1
a hydraulic line 500 which connects the primary chamber and the secondary chamber, and is connected with a wheel cylinder
Implementation Method 2
an elastic member 700 which is interposed between the first piston and the second piston, and provides elastic restoring force when the first piston and the second piston are moved
Data Source
AI summary
A master cylinder including: a primary chamber; a first piston which is provided in the primary chamber, and has one portion that is moved to the outside of the primary chamber by pressing a pedal; a secondary chamber which is provided to be adjacent to the primary chamber; a second piston which is provided in the secondary chamber, and has one portion that protrudes to the outside of the secondary chamber and is provided to be spaced apart from the first piston at a predetermined interval; and a hydraulic line which connects the primary chamber and the secondary chamber, and is connected with a wheel cylinder, in which the first piston is moved by pressing the pedal, and after the first piston is moved at a predetermined interval, the first piston and the second piston come into contact with each other, and are moved together.