Multi-Circuit Brake System with Regenerative Deceleration Control
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Solution Overview
Problem
Current multi-circuit brake systems for motor vehicles face challenges in optimally controlling the deceleration effect when combining mechanical braking with regenerative braking, leading to variable and unpredictable deceleration forces, which can compromise driver comfort and safety, especially when dealing with changes in vehicle speed and battery charging states.
Innovation Solution
A brake system with at least two separate hydraulic brake circuits, where one group is exclusively driven by a hydraulic pump and not directly actuated by a brake pedal, with a control device that adjusts the braking effect of the second group based on sensors detecting the braking request and actual deceleration effects, ensuring constant overall braking and managing active units like generators for energy recovery.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking with a generator is added to the brake system, then energy recovery is improved, but the deceleration effect becomes variable and unpredictable
Solution Approach 1:
The brake system is divided into two independent groups of brake circuits. The first group (directly actuated by brake pedal) provides predictable mechanical braking, while the second group (actuated by hydraulic pump) compensates for deceleration variations. This segmentation allows each group to have specialized functions, ensuring overall deceleration consistency while enabling energy recovery through the generator.
Solution Approach 2:
The control device continuously monitors the actual deceleration effect and compares it with the desired deceleration. Based on this feedback, the control device adjusts the hydraulic pump actuation of the second brake circuit group to compensate for variations caused by regenerative braking, maintaining consistent overall deceleration while preserving energy recovery capabilities.
2Reliability
If the brake pedal is used to compensate for deceleration changes, then deceleration consistency is improved, but driver comfort deteriorates
Solution Approach 1:
The control device acts as an intermediary between the driver's brake pedal input and the actual braking application. It processes the brake pedal signal and automatically adjusts the second brake circuit group via the hydraulic pump to maintain desired deceleration, eliminating the need for the driver to manually compensate for regenerative braking variations and ensuring comfort.
3Adaptability or versatility
If a third brake circuit is added for independent pressure regulation, then braking control flexibility is improved, but system complexity increases
Solution Approach 1:
The hydraulic pump serving the second brake circuit group is designed to perform multiple functions: it provides braking pressure for the second circuit group, compensates for deceleration variations caused by regenerative braking, and can independently regulate pressure without requiring a separate third brake circuit. This multi-functionality achieves the desired flexibility while minimizing system complexity.
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 enhanced reliability and comfort by maintaining a consistent braking effect, managing deceleration fluctuations, and preventing jerking, while allowing for efficient energy recovery and improved driving dynamics through precise control of hydraulic and regenerative braking.
Implementation Method 1
hydraulic brake circuits, with a hydraulic pump for generating and regulating hydraulic pressure in the brake circuits
Implementation Method 2
The drive motor can be operated as a generator in order to charge a battery used to drive the vehicle. Thus, kinetic energy of the vehicle during deceleration can be stored and reused later to accelerate the vehicle.
Data Source
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AI summary
The invention relates to a brake device and a hydraulic device for motor vehicles, comprising at least two hydraulic brake circuits (1, 2), which are directly connected to a master brake cylinder (9), and comprising a further brake circuit (3), which can be actuated via a control unit (22) independently from the master brake cylinder. Due to the separate hydraulic brake circuits (1, 2) in the region of the front axle, the required redundancy is provided, while the third brake circuit (3), which can be actuated independently of the master brake cylinder and typically acts on the rear wheels, during automatic actuation allows the consideration of a braking effect by additional units (20), such as a driven generator.