Electro-Mechanical Brake Booster Piston Arrangement
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Solution Overview
Problem
Conventional vehicle braking systems, particularly in electric and hybrid electric vehicles, face challenges in providing sufficient brake booster actuation due to the lack of vacuum pressure, necessitating alternative arrangements for enhancing brake pedal force application.
Innovation Solution
A boost arrangement for pressurizing the master cylinder, comprising a housing with a primary and secondary piston, where the primary piston is movable between positions to actuate the secondary piston, creating a boost chamber filled with brake fluid to actuate the master cylinder and operate the friction braking system, incorporating an electric brake force generator to displace brake fluid and provide hydraulic pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional vacuum-based brake booster systems are used, then sufficient brake booster actuation is achieved in internal combustion engine vehicles, but electric and hybrid electric vehicles lack sufficient vacuum pressure for effective brake booster actuation
Solution Approach 1:
The patent replaces the vacuum-based mechanical brake booster system with an electro-mechanical brake booster system that uses an electric motor to actuate the master cylinder. This substitution enables effective brake booster actuation in electric and hybrid electric vehicles that lack sufficient vacuum pressure from internal combustion engines, while maintaining reliable brake booster functionality across all vehicle types.
2Force
If electro-mechanical brake boosters are employed in electric and hybrid electric vehicles, then sufficient brake pedal force application is achieved, but system complexity increases compared to conventional vacuum-based systems
Solution Approach 1:
The electro-mechanical brake booster system is designed to perform multiple functions: it provides brake booster actuation for electric and hybrid electric vehicles, blends regenerative and friction braking forces, and maintains compatibility with conventional braking systems. This multi-functionality justifies the increased system complexity by delivering comprehensive braking control across different vehicle types and operating modes.
Solution Approach 2:
The patent introduces a brake fluid displacement mechanism as an intermediary between the electric motor and the master cylinder. The electric motor actuates a piston that displaces brake fluid, which in turn actuates the master cylinder. This intermediary fluid displacement mechanism enables effective force transmission while managing the complexity of integrating electro-mechanical actuation with conventional hydraulic braking systems.
3Loss of energy
If regenerative braking is blended with friction braking, then energy conservation and extended electrical range are achieved, but sufficient friction brake force must still be provided for reliable braking performance
Solution Approach 1:
The electro-mechanical brake booster system dynamically adjusts the blend between regenerative and friction braking forces based on vehicle operating conditions. The electric motor can modulate the force applied to the master cylinder to optimize the combination of regenerative energy recovery and friction braking performance, ensuring sufficient friction brake force is provided when needed while maximizing energy conservation during appropriate operating modes.
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 effectively enhances brake pedal force application, enabling efficient blending of regenerative and friction braking, ensuring reliable vehicle braking performance even in vehicles lacking conventional vacuum-based systems.
Implementation Method 1
The primary piston and a secondary piston that cooperate to displace brake fluid in response to movement of the primary piston from a first position and a second position. Displacement of brake fluid from the boost chamber actuates the master cylinder to operate the hydraulic brake device.
Data Source
AI summary
A boost arrangement for pressurizing a master cylinder of a vehicle braking system of a vehicle includes a housing, a primary piston and a secondary piston. The housing defines a boost chamber filled with brake fluid. The primary piston is disposed in the boost chamber and defines an opening extending therethrough. The secondary piston has an end extending into the opening defined by the primary piston.