Brake Control Device for Electric Vehicles
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Solution Overview
Problem
Existing brake control systems for electric vehicles, such as those described in Patent Document #1, fail to optimize upstream and downstream braking pressures, leading to suboptimal braking performance during regenerative braking.
Innovation Solution
A brake control device and method that adjust upstream and downstream brake pressures in electric vehicles by reducing pressures for driving wheels and increasing them for non-driving wheels during regenerative braking, using a master cylinder and brake actuators to achieve coordinated regeneration control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coordinated regeneration control is performed by calculating frictional braking torque to supplement regeneration torque shortage, then braking torque can be provided to meet target braking torque, but upstream and downstream braking pressures cannot be optimized according to vehicle state, resulting in suboptimal braking performance
Solution Approach 1:
The patent applies local quality by differentiating pressure control strategies for driving wheels versus non-driving wheels. During regenerative braking, downstream brake pressure is reduced for driving wheels (where regenerative braking is applied) and increased for non-driving wheels (where friction braking supplements the braking force). This localized differentiation optimizes braking performance for each wheel type based on its specific functional requirements.
Solution Approach 2:
The patent implements dynamic pressure control by continuously adjusting upstream and downstream brake pressures based on real-time vehicle state and braking requirements. The master cylinder dynamically controls upstream pressure, while brake actuators dynamically adjust downstream pressure, creating a flexible and adaptive pressure control system that responds to changing braking conditions.
2Reliability
If downstream brake pressure is increased to supplement regeneration torque shortage, then target braking torque can be achieved, but the dynamic range required for downstream brake pressure increases, necessitating larger reservoir tanks
Solution Approach 1:
The patent reduces the required reservoir tank volume by applying different pressure control strategies to different wheel types. Downstream brake pressure is reduced for driving wheels during regenerative braking, while being increased only for non-driving wheels. This localized approach minimizes the overall dynamic range requirement for downstream brake pressure, thereby reducing the volume of reservoir tanks needed.
Solution Approach 2:
The patent combines regenerative braking and friction braking systems into a coordinated unified control system. The master cylinder and brake actuators work together to optimize the distribution of braking forces between regenerative and friction braking, allowing efficient use of brake fluid across both systems and reducing the overall fluid storage requirement.
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 approach enhances braking performance by optimizing pressure distribution, reducing the dynamic range required for downstream brake pressures and allowing for the same brake fluid mass to be used across both wheel types, eliminating the need for large reservoir tanks.
Implementation Method 1
a master cylinder that generates a common upstream brake pressure for the brake devices
Implementation Method 2
brake actuators that generate individual downstream brake pressures for the brake devices on the basis of the upstream brake pressure
Implementation Method 3
a plurality of brake devices, one provided to correspond to each one of the driving wheels and the non-driving wheels, that provide braking forces to the wheels due to brake fluid pressures
Data Source
AI summary
A brake control device mounted to a vehicle that comprises a pair of driving wheels and a pair of non-driving wheels controls an upstream brake pressure generated by a master cylinder and downstream brake pressures generated by brake actuators so that, during regenerative braking, the downstream brake pressures to brake devices corresponding to the driving wheels are reduced to be lower than the upstream brake pressure, and the downstream brake pressures to brake devices corresponding to the non-driving wheels are increased to be higher than the upstream brake pressure.