Vehicle Braking Control for Brake Temperature and SOC Limits
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Solution Overview
Problem
Conventional braking control devices for vehicles fail to effectively manage friction brake temperature, leading to reduced braking effectiveness and discomfort for drivers during automated driving or Adaptive Cruise Control (ACC) operations, especially when traveling downhill.
Innovation Solution
A braking control device that includes a processor configured to estimate brake temperature and manage regenerative and friction braking forces, prohibiting automated braking operations when the brake temperature is high and the battery charge is sufficient, thereby protecting the friction brake.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If friction braking is used to decelerate the vehicle during automated driving, then deceleration performance is improved, but brake temperature rises causing reduced braking effectiveness
Solution Approach 1:
The braking control device dynamically switches between friction braking and engine braking based on real-time brake temperature conditions. When brake temperature is below a threshold, friction braking is applied for effective deceleration. When temperature exceeds the threshold, the system transitions to engine braking to maintain deceleration capability while preventing brake overheating.
Solution Approach 2:
The system changes the braking mechanism parameter based on temperature conditions. At normal temperatures, the friction brake is activated for deceleration. When temperature rises above the threshold, the control parameter switches to use engine braking instead, thereby maintaining deceleration performance while avoiding thermal degradation of the friction brake.
2Extent of automation
If friction braking is frequently applied during automated driving, then automated braking control is improved, but driver comfort deteriorates due to unpredictable braking effectiveness
Solution Approach 1:
The braking control device incorporates temperature feedback from the friction brake to automatically adjust the braking strategy. By monitoring brake temperature and using this feedback to switch between friction braking and engine braking, the system maintains predictable braking effectiveness, preventing driver discomfort while preserving automated braking functionality.
3Temperature
If regenerative braking is reduced to prevent brake temperature rise, then brake temperature control is improved, but energy recovery efficiency deteriorates
Solution Approach 1:
The system dynamically adjusts the mix of regenerative and friction braking based on brake temperature. When temperature is acceptable, regenerative braking is maximized for energy recovery. When temperature approaches the threshold, the system progressively reduces friction braking usage and increases reliance on regenerative braking and engine braking, thereby controlling temperature while minimizing energy loss.
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 effectively prevents a decline in braking effectiveness and reduces driver discomfort by managing brake temperature and battery charge levels, ensuring predictable braking performance during automated driving.
Implementation Method 1
a brake temperature estimator to estimate a brake temperature of the friction brake
Implementation Method 2
the brake pads become pressed against the brake disc through hydraulic pressure supplied from a master cylinder causing frictional resistance to be generated between the brake pads and the brake disc
Implementation Method 3
the brake pads become pressed against the brake disc through hydraulic pressure supplied from a master cylinder
Implementation Method 4
a regenerative brake and friction brake... generate, without a driver performing a braking operation, regenerative braking force from a regenerative brake
Data Source
AI summary
A vehicle includes a regenerative brake of a rotating electric machine and a friction brake which is a mechanical brake as braking means for applying a braking force to rotations of the left and right wheels at the front and rear of the vehicle. The vehicle also includes an SOC information obtaining part that obtains an amount of charge (SOC) of a battery of the vehicle and an ECU. The ECU may include a VSA modulator and an ACC-ECU that generate, without a braking operation of the driver, a regenerative braking force with the regenerative brake and a friction braking force with the friction brake. The ECU prohibits an operation of the VSA modulator and/or an operation of the ACC-ECU according to a temperature of the friction brake and the amount of charge (SOC) of the battery.