Fuel Cell Stop Mode Control for Durability and Acceleration
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Solution Overview
Problem
Fuel cell vehicles face challenges in extending the stop mode of fuel cells during driving, which affects durability and acceleration performance, as existing methods do not effectively manage power generation stop/start transitions, leading to frequent stopping and starting.
Innovation Solution
A method of controlling the fuel cell operation mode by determining standard torque and state of charge values for stop and start modes, converting between modes based on driver-demanded torque, state of charge, regenerative braking, downhill driving, and available output voltage to extend the stop mode and improve durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the fuel cell stop mode is extended to improve fuel efficiency, then fuel efficiency is improved, but acceleration performance deteriorates due to voltage formation time
Solution Approach 1:
The control method performs preliminary actions by determining predicted torque requirements and pre-managing fuel cell restart timing before actual acceleration occurs. The controller predicts future torque demands and schedules fuel cell restarts in advance, allowing the fuel cell to begin voltage formation before power is actually needed, thus eliminating acceleration delay while maintaining extended stop modes for fuel efficiency.
Solution Approach 2:
The control method implements feedback mechanisms by continuously monitoring actual torque requirements, battery state of charge, and fuel cell voltage status. The controller adjusts restart timing based on feedback from these parameters, optimizing the balance between extending stop modes for fuel efficiency and ensuring timely restarts for acceleration performance.
2Use of energy by moving object
If the fuel cell stop mode is extended to improve fuel efficiency, then fuel efficiency is improved, but durability deteriorates due to frequent start/stop cycles
Solution Approach 1:
The control method uses preliminary action by predicting torque requirements in advance and scheduling fuel cell restarts before they are critically needed. This allows the system to extend stop modes longer than conventional methods while avoiding frequent restarts, as the fuel cell is restarted only when predicted torque demands indicate it is appropriate, thereby improving both fuel efficiency and durability.
Solution Approach 2:
The control method enables self-service by having the system autonomously manage restart timing based on predicted torque requirements and current operating conditions. The controller independently determines optimal restart moments without requiring frequent external interventions, reducing start/stop cycle frequency while maintaining system responsiveness to actual power demands.
3Speed
If the fuel cell restarts quickly to improve acceleration performance, then acceleration performance is improved, but fuel efficiency deteriorates due to reduced stop mode duration
Solution Approach 1:
The control method applies preliminary action by predicting torque requirements in advance and scheduling fuel cell restarts optimally. Instead of immediately restarting the fuel cell upon detecting torque demand, the controller uses predicted future torque needs to determine the most efficient restart timing, allowing stop modes to be extended as long as possible while ensuring restarts occur timely enough to meet acceleration requirements.
Solution Approach 2:
The control method implements dynamics by making the restart timing flexible and adaptive rather than fixed or immediate. The controller dynamically adjusts restart decisions based on real-time conditions including predicted torque requirements, battery state of charge, and current fuel cell status, optimizing the balance between stop mode duration for fuel efficiency and restart timing for acceleration performance.
4Speed
If the fuel cell restarts quickly to improve acceleration performance, then acceleration performance is improved, but durability deteriorates due to increased start/stop frequency
Solution Approach 1:
The control method uses preliminary action by predicting torque requirements in advance and scheduling fuel cell restarts optimally before they are needed. This allows the system to maintain acceleration performance by ensuring fuel cell readiness while extending stop modes longer than conventional immediate-restart methods, thereby reducing overall start/stop frequency and improving durability.
Solution Approach 2:
The control method enables self-service by autonomously managing restart timing based on predicted torque requirements and system state. The controller independently optimizes restart decisions to minimize start/stop frequency while ensuring acceleration performance is maintained, reducing durability degradation from frequent cycling without compromising speed response.
Data Source
AI summary
Disclosed is a method of controlling an operation mode of a fuel cell in a fuel cell vehicle wherein, (a) when a driver-demanded torque is lower than a first torque, and a current state of charge (SOC) in a battery is higher than a first SOC, the operation mode of the fuel cell is converted to a stop mode, and (b) when the driver-demanded torque is higher than a second torque, or the current SOC in the battery is lower than a second SOC, the operation mode is converted to a start mode, wherein the second torque is higher than the first torque and the second SOC is lower than the first SOC.