Recuperative Braking Control via Isolating Valve Segmentation
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Solution Overview
Problem
Existing vehicle braking systems face challenges in efficiently converting kinetic energy into electrical energy while maintaining desired deceleration and comfort, particularly in systems with both decouplable and non-decouplable brake circuits, where the use of electric motors and hydraulic systems can lead to abrupt braking and reduced energy conversion efficiency.
Innovation Solution
A control device with an isolating valve that connects and decouples the wheel brake cylinders from the master brake cylinder, allowing for independent control of brake pressure and generator torque on each axle, enabling simultaneous hydraulic and regenerative braking without altering the driver's brake actuation feel, and optimizing energy conversion by adjusting hydraulic components like pumps and valves based on sensor inputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the electric motor is used for regenerative braking on multiple axles, then the energy conversion efficiency is improved, but the vehicle deceleration becomes difficult to control
Solution Approach 1:
The braking system is divided into two independent brake circuits (first and second brake circuits), each controlling different axles. The isolating valve separates these circuits, allowing independent control of regenerative braking on different axles. This segmentation enables precise control of generator braking torque while maximizing energy recovery from multiple axles simultaneously.
2Force
If the brake pressure in the wheel brake cylinder is increased, then the hydraulic braking torque is improved, but the generator braking torque is reduced
Solution Approach 1:
The system dynamically adjusts the isolating valve state based on real-time operating conditions (brake pedal actuation, accelerator pedal position, vehicle speed, battery charge state). During regenerative braking, the valve closes to isolate the hydraulic circuit, allowing maximum generator torque. During hydraulic braking, the valve opens to allow brake pressure buildup. This dynamic switching optimizes the balance between hydraulic and regenerative braking torques.
3Loss of energy
If the isolating valve is closed to enable pure regenerative braking, then the energy conversion efficiency is improved, but the driver's brake actuation feel is altered
Solution Approach 1:
The braking system is divided into two independent brake circuits (first and second brake circuits), each controlling different axles. The isolating valve separates these circuits, allowing independent control of regenerative braking on different axles. This segmentation enables precise control of generator braking torque while maximizing energy recovery from multiple axles simultaneously.
Solution Approach 2:
The control device acts as an intermediary between the driver's brake input and the actual braking application. It processes sensor signals (brake pedal actuation, accelerator pedal position, vehicle speed, battery charge state) and intelligently determines when to close the isolating valve for pure regenerative braking versus when to allow hydraulic braking. This intermediary control maintains natural brake actuation feel while maximizing energy recovery opportunities.
4Productivity
If the electric motor brakes all wheels, then the productivity of energy recovery is improved, but the system complexity increases
Solution Approach 1:
The isolating valve serves multiple functions: it isolates the first brake circuit from the master brake cylinder during regenerative braking, maintains hydraulic connection during hydraulic braking, and enables flexible control configurations. This multi-functional component achieves complex control objectives without proportionally increasing system complexity. The system can adaptively configure which axles use regenerative braking based on real-time conditions.
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 allows for faster battery charging and reliable deceleration without abrupt braking, maintaining driver comfort and increasing energy conversion efficiency by enabling high generator braking torque on multiple axles while maintaining the desired overall vehicle deceleration.
Implementation Method 1
an electric motor which can be operated as a generator to recuperate braking energy and, in generator mode, causes a braking force on the wheels
Implementation Method 2
A wheel brake cylinder of the hydraulic brake system is assigned to each of the wheels of the vehicle and is connected to the master brake cylinder of the hydraulic brake system via at least one brake line
Data Source
Figure 1
Figure 2a
Figure 2b~2c
AI summary
The control device (10) comprises an engine and hydraulic drive unit (12), by which one of the sensor signals (16) is provided by an on-vehicle sensor (14) corresponding to an operation amount of an operation of an input element (23). The engine and hydraulic drive unit outputs a closing signal (44) to a division valve (46) additionally in consideration of the sensor signal, the reference variables (18,20) or the quantity derived from them. A wheel brake cylinder (24) of a brake circuit (26) is connected with a master brake cylinder (48) of the brake system through the division valve. An independent claim is included for a method for operating a recuperative brake system of a vehicle.