Fuel Cell Vehicle Start Control via Voltage Thresholds
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Solution Overview
Problem
Conventional methods for starting fuel cell vehicles at low temperatures are inefficient due to inaccurate estimation of fuel cell temperature completion, leading to delayed starts and potential fuel cell deterioration, as they do not account for non-uniform cell voltages, frozen water, and hybrid battery states.
Innovation Solution
A control method that estimates the available output power of both the fuel cell and high-voltage battery by analyzing real-time stack performance and temperature rise, determining if the combined output power exceeds the required power for vehicle start, thereby optimizing the fuel cell temperature increase and preventing unnecessary delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional temperature estimation methods are used to determine temperature-raising completion, then the starting process is simplified, but the accuracy of temperature completion determination deteriorates, causing unnecessary delays
Solution Approach 1:
The patent replaces conventional temperature-based control mechanisms with voltage-based control. Instead of monitoring physical temperature sensors to determine when the fuel cell has warmed up, the system monitors voltage values across fuel cell stacks. When voltages reach predetermined thresholds, the system determines temperature-raising completion and allows vehicle starting, eliminating the need for complex temperature monitoring while reducing starting delays.
Solution Approach 2:
The patent changes the control parameter from temperature to voltage. By monitoring voltage changes in fuel cell stacks during the warming process and comparing them against predetermined voltage thresholds, the system can accurately determine when the fuel cell has reached sufficient temperature without directly measuring temperature, thus simplifying the control process while improving timing accuracy.
2Speed
If the vehicle is started before accurate temperature completion is determined, then starting speed is improved, but fuel cell output power becomes insufficient, causing power limitation and potential deterioration
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring voltage values of individual fuel cell stacks and comparing them against predetermined thresholds. This feedback allows the control system to accurately determine when the fuel cell has warmed up sufficiently and is ready to provide reliable power output, preventing premature starting that would result in power insufficiency and potential fuel cell deterioration.
Solution Approach 2:
The patent performs preliminary voltage threshold verification before allowing vehicle starting. By checking whether voltage values of all fuel cell stacks exceed predetermined thresholds before permitting the start command, the system ensures that the fuel cell is in a safe operating state with sufficient power output capability, thus preventing power limitation and deterioration while enabling rapid starting.
Data Source
AI summary
A control method and system for starting a fuel cell vehicle is provided. The method includes setting a first output power that is an output power required for driving the vehicle and beginning to increase the fuel cell temperature after setting the first output power. In addition, available output power of a fuel cell is estimated and a discharge power of a high-voltage battery is received. A second output power that is a sum of the available output power of the fuel cell and the discharge power of the high-voltage battery is calculated. The method further includes determining whether the second output power is greater than the first output power and determining whether starting of the vehicle is allowable based on the determination of whether the second output power is greater than the first output power.