Regenerative Braking Control for Vehicle Deceleration Interruptions
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Solution Overview
Problem
Existing regenerative braking systems in vehicles often experience brief delays or interruptions in recuperative mode, particularly at the beginning or during braking, leading to a loss of braking effect and reduced driver acceptance of hybrid and electric vehicles.
Innovation Solution
A control device that determines the executability of the recuperative mode and adjusts the brake circuit valves to increase hydraulic deceleration by the first wheel brake cylinders, ensuring a brief and unnoticed delay or interruption, thereby maintaining braking effectiveness and comfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the recuperative mode is delayed or interrupted for brief periods (up to two seconds), then the braking system can maintain hydraulic pressure stability, but the regenerative braking effect is lost temporarily
Solution Approach 1:
The control device detects potential interruptions in recuperative mode in advance (checking clutch state, accelerator pedal position, gear changes) and prepares the hydraulic brake system by activating the first wheel brake cylinders before the interruption occurs, ensuring continuous braking effect without noticeable delay
Solution Approach 2:
The system dynamically switches between recuperative braking and hydraulic braking modes based on real-time vehicle conditions. When an interruption is detected, the control device transitions from electric motor regenerative braking to hydraulic braking assistance, and vice versa, maintaining optimal braking performance throughout the transition
2Ease of operation
If the first wheel brake cylinders are activated to compensate for recuperative mode delays, then braking comfort is maintained, but the complexity of the brake control system increases
Solution Approach 1:
The control device performs multiple functions: it manages recuperative mode activation, monitors vehicle conditions (clutch, accelerator, gear state), detects interruptions, and controls both electric motor braking and hydraulic braking systems. This multi-functionality is achieved through a single integrated control unit that coordinates all braking operations without requiring additional separate control systems
Solution Approach 2:
The control device continuously monitors vehicle operating conditions including clutch engagement state, accelerator pedal position, and gear changes to detect when recuperative mode interruptions will occur. This feedback mechanism allows the system to anticipate and prepare for interruptions, activating hydraulic braking in advance to maintain braking comfort while avoiding unnecessary system complexity
3Force
If the brake pressure is increased in the first wheel brake cylinders during recuperative mode delay, then the braking deceleration is maintained, but the energy consumption increases
Solution Approach 1:
The system applies hydraulic braking only partially and temporarily - specifically during the brief interruption period of up to two seconds when recuperative mode is delayed. The first wheel brake cylinders are activated just enough to compensate for the lost regenerative braking effect during this short interval, rather than maintaining full hydraulic braking continuously, thus minimizing energy consumption while ensuring braking force is maintained when needed
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
The solution allows for reliable compensation of brief delays or interruptions in the recuperative mode, enhancing driver acceptance and comfort by maintaining consistent braking performance, even during short delays or interruptions in the recuperative operation.
Implementation Method 1
the pressure medium displaced from the master brake cylinder to the wheel brakes by the actuation of the brake pedal
Implementation Method 2
When braking the vehicle using the electric drive to simultaneously charge a battery
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3a~3b
AI summary
The invention relates to a regenerative braking system for a vehicle having a master brake cylinder (18); two brake circuits (10, 12), respectively having at least one first wheel brake cylinder (14a, 14b), one second wheel brake cylinder (16a, 16b), one storage chamber (46a, 46b) and at least one valve (32a, 32b, 34a, 34b, 36a, 36b, 38a, 38b); an electric motor; and a control device (50), which is designed to determine if a generative vehicle deceleration equal to a requested target vehicle deceleration (adriver) can be effected by means of a generative operation of the electric motor, or if this is delayed or interrupted for a time interval of at most two seconds, and, if necessary, to control at least the valves (32a, 32b, 34a, 34b, 36a, 36b, 38a, 38b) of the two brake circuits (10, 12) in such a way that at least a first hydraulic vehicle deceleration effected by means of the first wheel brake cylinders (14a, 14b) of the two brake circuits (10, 12) can be increased. The invention further relates to a method for operating a regenerative braking system of a vehicle.