Electric Booster Input Piston Segmentation for Regenerative Braking
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Solution Overview
Problem
The existing electric booster systems, as described in Patent Document 1, face limitations in regenerative braking efficiency due to their structure, which restricts the recoverable energy during regenerative braking, as they rely on a limited clearance between piston segments for hydraulic pressure adjustment.
Innovation Solution
The electric booster incorporates a piston with a compression chamber, an electric actuator, an input piston, and spring devices to create a predetermined clearance between the input piston and an input member, allowing for increased regenerative braking capacity by adjusting the relative positions of the pistons during regenerative coordination control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electric booster uses a limited clearance between piston segments for hydraulic pressure adjustment, then the jump-in characteristics are achieved, but the regenerative braking capacity is restricted
Solution Approach 1:
The input piston is divided into multiple segments (first input piston segment, second input piston segment) with a clearance between them. This segmentation allows the hydraulic pressure to act on different segments at different stages, enabling both jump-in characteristics and enhanced regenerative braking capacity by providing additional clearance for pressure adjustment during energy recovery operations.
2Speed
If the clearance between input piston segments is minimized for jump-in characteristics, then brake response is improved, but the range for regenerative braking control is limited
Solution Approach 1:
The invention introduces a dual-stage clearance mechanism: a first clearance between the first input piston segment and the piston for jump-in characteristics, and a second clearance between the second input piston segment and the piston for regenerative braking control. This multi-dimensional approach to clearance management allows the system to achieve rapid brake response while simultaneously providing sufficient control range for energy recovery operations.
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 enables the electric booster to achieve jump-in characteristics and significantly enhance regenerative braking capacity, improving energy recovery during regenerative braking while maintaining good brake pedal feel and control.
Implementation Method 1
a first spring device that resiliently holds the input piston at a predetermined position in an axial direction of the input piston with respect to the piston
Implementation Method 2
a second spring device which applies a spring force to the input member in a direction in which the input member is moved away from the input piston, wherein a predetermined clearance is formed between the input piston and the input member by means of the second spring device when the brake pedal is not in operation
Implementation Method 3
an electric actuator which moves the piston; a compression chamber; wherein the distal end of the input piston faces the compression chamber of the master cylinder
Data Source
AI summary
An electric motor is controlled according to the back and forth movement of an input rod, which is caused by brake pedal operation; a primary piston is propelled to generate hydraulic brake pressure in a master cylinder; and the hydraulic brake pressure is fed back to the input rod through an input piston. The input piston is resiliently held by springs with respect to the primary piston. A jump-in clearance is created between the input piston and the input rod by a rearward spring. At the initial stage of braking, hydraulic brake pressure is not transmitted to the input rod due to the jump-in clearance, which provides jump-in characteristics. The jump-in clearance can be set, regardless of the amount of a relative displacement between the primary piston and the input piston, so that the range of adjustment for regenerative braking can be set larger than the jump-in clearance.