Fuel Cell Vehicle Brake Control for Slope Rolling Escape
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Solution Overview
Problem
Fuel cell vehicles face challenges in escaping rolling situations on slopes due to insufficient regenerative braking torque, especially when the battery is not chargeable or overcharged, leading to unstable driving conditions.
Innovation Solution
A control system and method that derive the required target regenerative braking torque and control the brake system to generate additional braking torque when the available regenerative braking torque is insufficient, allowing the vehicle to escape rolling situations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative braking is used to recover kinetic energy, then energy recovery efficiency is improved, but when the battery is not chargeable or overcharged, the vehicle cannot escape rolling situations on slopes
Solution Approach 1:
The brake control system dynamically adjusts braking torque based on real-time detection of rolling situations and battery chargeability status. When the vehicle rolls on a slope and the battery cannot accept regenerative braking energy, the system automatically switches to friction braking to provide sufficient escape torque, ensuring reliable vehicle control under varying operational conditions.
Solution Approach 2:
The controller acts as an intermediary between the regenerative braking system and friction braking system. It monitors the battery's chargeability and seamlessly coordinates between the two braking mechanisms, switching from regenerative braking to friction braking when the battery is overcharged or not chargeable, thereby maintaining vehicle escape capability.
2Weight of moving object
If the battery capacity is small to maintain vehicle weight, then vehicle efficiency is improved, but the vehicle is frequently exposed to non-chargeable or overcharged states
Solution Approach 1:
The system applies friction braking in addition to or instead of regenerative braking when the battery cannot accept energy. This partial use of friction braking compensates for the limited battery capacity, allowing the vehicle to handle rolling situations on slopes even when regenerative braking alone is insufficient due to battery chargeability constraints.
Solution Approach 2:
The brake control system changes the braking torque parameter dynamically based on vehicle speed, slope angle, and battery chargeability status. When the battery is overcharged or not chargeable, the system adjusts the braking torque distribution to ensure sufficient escape capability, adapting to different operational conditions without requiring larger battery capacity.
3Loss of energy
If regenerative braking torque is insufficient when battery is overcharged, then energy recovery is limited, but the vehicle cannot escape rolling situations on slopes
Solution Approach 1:
The system merges regenerative braking and friction braking into a unified brake control system. When the battery is overcharged or not chargeable and regenerative braking torque is insufficient, the friction braking system is activated to supplement the braking torque, ensuring the vehicle can escape rolling situations on slopes despite limited energy recovery capability.
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
Enables fuel cell vehicles to effectively escape rolling situations on slopes by supplementing insufficient regenerative braking torque with braking torque from the brake system, thereby ensuring stability and normal driving conditions.
Implementation Method 1
Regenerative braking means recovering kinetic energy of a vehicle by converting the kinetic energy into electrical energy through an electric motor connected to the wheels of the vehicle
Implementation Method 2
control the brake system to generate braking torque as much as insufficient regenerative braking torque
Data Source
AI summary
A control system for a fuel cell vehicle includes a driving motor of the fuel cell vehicle, a brake system of the fuel cell vehicle, and a controller configured to derive a required target regenerative braking torque when the fuel cell vehicle rolls in an opposite direction to a traveling direction on a slope and, when an available regenerative braking torque of the driving motor is less than the required target regenerative braking torque, control the brake system to generate braking torque by as much as a difference between the required target regenerative braking torque and the available regenerative braking torque.