Fuel Cell Stack Output Control for Uphill and Downhill Driving
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Fuel cell vehicles experience decreased fuel efficiency and rapid deterioration of the fuel cell stack when driving uphill due to excessive stack output and increased power generation, which is exacerbated by battery state of charge (SOC) fluctuations.
Innovation Solution
A device and method that calculates appropriate stack output based on battery SOC and uphill altitude to prevent excessive stack output and durability issues by determining a lower value between required and basic stack outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the stack output is increased to meet power demand during uphill driving, then the vehicle can maintain driving performance, but fuel consumption increases and fuel cell stack durability deteriorates
Solution Approach 1:
The system performs preliminary charging of the battery during downhill driving or when excess power is available, storing energy in advance for use during uphill driving. This eliminates the need to increase stack output during uphill driving, thereby reducing fuel consumption while maintaining driving performance.
Solution Approach 2:
The battery acts as an intermediary energy storage device between the fuel cell stack and the motor. It buffers power demands during uphill driving by discharging stored energy, allowing the stack to operate at lower, more efficient output levels while still meeting the vehicle's power requirements.
2Power
If the stack output is increased to meet power demand during uphill driving, then the vehicle can maintain driving performance, but the durability of the fuel cell stack deteriorates
Solution Approach 1:
The system charges the battery in advance during periods of low power demand or downhill driving, so that during uphill driving the battery can supplement stack output. This prevents the stack from operating at high output levels that cause rapid deterioration, thereby extending stack durability while maintaining required power performance.
Solution Approach 2:
Instead of relying solely on the stack to meet peak power demands, the system uses the battery to provide partial power during uphill driving. This shared power delivery approach reduces the stack's workload and operating stress, preventing rapid durability deterioration.
3Loss of energy
If the battery SOC is maintained at high level to prevent fuel cell operation, then fuel consumption is reduced, but the vehicle cannot meet power demand during uphill driving
Solution Approach 1:
The system dynamically adjusts the battery SOC management strategy based on driving conditions. During uphill driving, it allows SOC to decrease to provide additional power. During downhill or flat driving, it recharges the battery. This dynamic approach ensures both fuel efficiency and adequate power availability when needed.
Solution Approach 2:
The system changes the operational parameters of the battery SOC threshold dynamically. Instead of maintaining a fixed high SOC level, it adjusts the acceptable SOC range based on upcoming driving demands (e.g., detecting uphill segments ahead), allowing the battery to discharge during uphill driving while maintaining overall fuel efficiency.
Data Source
AI summary
Disclosed are a device and a method for improving the fuel efficiency of a fuel cell vehicle in uphill and downhill driving. The device may calculate an appropriate stack output to be generated from a fuel cell stack based on the SOC of a battery as well as an uphill altitude at which the vehicle traveling on the uphill road has to travel further to reach the highest altitude when determining the degree of the stack output generated from the fuel cell stack when driving on the uphill road, and may prevent fuel consumption from increasing to generate excessive stack output while driving on an uphill road or the durability of the fuel cell stack from being deteriorated.