Decoupled Brake System for Adaptive Torque Blending
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Solution Overview
Problem
Conventional brake systems in hybrid vehicles require driver effort to blend recuperative and friction braking torques, leading to increased driver workload and potential instability, especially during low-speed braking and cornering, while existing brake-by-wire systems are costly and complex.
Innovation Solution
A decouplable brake system with a separator valve and control valve allows independent control of wheel-brake cylinders, enabling adaptive blending of braking torques without direct driver input, using sensors to determine desired braking torque and adjusting pressure through a control valve for efficient recuperation and stable braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the driver directly controls the brake circuit via the brake pedal and master brake cylinder, then the braking system is simple and reliable, but the driver workload increases and blending precision deteriorates
Solution Approach 1:
The brake system is divided into a first brake circuit connected to the master brake cylinder for direct driver control, and a second brake circuit decoupled from the master brake cylinder for automated control. This segmentation allows the driver to control only the necessary portion while the automated system handles blending, reducing driver workload without requiring complete system redesign
Solution Approach 2:
A control unit acts as an intermediary between the driver's braking input and the second brake circuit. The control unit receives signals from the master brake cylinder, determines desired braking torque, and controls the second brake circuit accordingly. This intermediary enables automated blending while maintaining simplicity in the overall system architecture
2Reliability
If the conventional friction brake torque is increased to compensate for low-speed braking, then braking stability is improved, but energy loss increases and recuperation efficiency deteriorates
Solution Approach 1:
The control unit dynamically adjusts the braking torque distribution between the first and second brake circuits based on real-time operating conditions such as vehicle speed, deceleration rate, and recuperative brake availability. At low speeds where recuperative braking is unavailable, the system automatically increases friction brake torque to maintain stability, while at higher speeds it maximizes recuperative braking to reduce energy loss
Solution Approach 2:
The control unit continuously monitors the actual braking torque from the master brake cylinder and the recuperative braking torque, then adjusts the second brake circuit's torque contribution accordingly. This feedback mechanism ensures optimal blending that maintains braking stability while minimizing energy loss by maximizing recuperation whenever possible
3Ease of operation
If the brake system uses complex electronics and mechanics/hydraulics for automated blending, then driver workload is reduced, but system cost and complexity increase
Solution Approach 1:
The system segments control functions by maintaining direct connection between the master brake cylinder and the first brake circuit for straightforward driver control, while decoupling the second brake circuit for specialized automated control. This segmentation allows automated blending functionality to be added without redesigning the entire brake system, thereby limiting the increase in overall complexity
Solution Approach 2:
The control unit serves multiple functions: it monitors braking torque from the master brake cylinder, determines desired braking torque based on vehicle conditions, controls the second brake circuit's torque contribution, and ensures stable braking performance. By consolidating these functions in a single control unit, the system achieves automated blending without proportionally increasing 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 reduces driver workload, ensures efficient recuperation, and provides stable braking performance across various driving conditions, including cornering and reverse driving, at a lower cost compared to traditional brake-by-wire systems.
Implementation Method 1
The pressure signal is understood, for example, to be a power transmitted from the master brake cylinder to the at least one first wheel-brake cylinder
Implementation Method 2
a control valve is configured at such close proximity to the connection of the first brake circuit at the braking medium reservoir that an inflow of the braking medium from the braking medium reservoir to the first wheel-brake cylinder is controllable by the control valve
Implementation Method 3
This transmitted power induces the first wheel-brake cylinder to exert a braking torque on the first wheel assigned thereto
Data Source
AI summary
A brake system for a vehicle having a master brake cylinder, which provides a pressure signal, having a brake-medium reservoir connected to the master brake cylinder, and a first brake circuit, which is coupled by a first input to the master brake cylinder and by a second input to the brake-medium reservoir, and having at least one first wheel-brake cylinder, which is mounted at a first wheel, in order to exert a force corresponding to the pressure signal onto the first wheel, and having a separator valve, which is configured between the first input and the first wheel-brake cylinder, to prevent further transmission of the pressure signal upon receipt of a supplied closing signal; and having a control valve, which is configured between the first input and the first wheel-brake cylinder; in order to control an inflow of a brake medium from brake-medium reservoir to the first wheel-brake cylinder. In addition, a method for controlling a corresponding brake system is also described.