Fuel Cell Vehicle SOC Control for Low-Hydrogen Power Continuity
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Solution Overview
Problem
Fuel cell vehicles experience sudden significant restrictions in traveling performance due to early depletion of hydrogen fuel, as the energy stored in batteries is lower than hydrogen energy, leading to inadequate power supply when fuel runs out.
Innovation Solution
An FCV system with an adjustable FC system output, power storage, and a controller that adjusts the State of Charge (SOC) of the power storage to a target SOC, lowering it when fuel levels decrease, to prioritize the use of the power storage and prevent sudden performance restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the FC system is used as the primary power source, then hydrogen energy can be efficiently utilized, but traveling performance is suddenly significantly restricted when fuel runs out earlier than battery SOC depletion
Solution Approach 1:
The patent applies dynamics by making the target SOC a variable parameter that changes dynamically based on the remaining fuel amount. The target SOC is set to decrease as fuel decreases, allowing the power storage to discharge more when fuel is low, thereby preventing sudden performance restriction when fuel runs out.
Solution Approach 2:
The patent applies preliminary action by proactively adjusting the target SOC before fuel depletion occurs. The control device calculates the remaining travel distance based on current fuel levels and sets the target SOC in advance to ensure sufficient battery discharge capacity will be available when fuel runs out, avoiding sudden performance restriction.
2Quantity of substance
If the target SOC is maintained at a high level, then the power storage retains more energy, but output from the power storage is restricted when fuel decreases, limiting traveling performance
Solution Approach 1:
The patent applies dynamics by making the target SOC a variable parameter that changes dynamically based on the remaining fuel amount. The target SOC is set to decrease as fuel decreases, allowing the power storage to discharge more when fuel is low, thereby preventing sudden performance restriction when fuel runs out.
Solution Approach 2:
The patent applies parameter changes by modifying the target SOC parameter based on fuel levels. When fuel amount decreases, the target SOC parameter is reduced, which enables the power storage to provide more discharge output. This parameter adjustment resolves the contradiction between maintaining high energy storage and ensuring sufficient productivity.
3Power
If the FC system output is increased to maintain traveling performance, then power supply is sufficient, but fuel depletes faster, causing earlier run-out
Solution Approach 1:
The patent applies preliminary action by proactively adjusting the target SOC before fuel depletion occurs. The control device calculates the remaining travel distance based on current fuel levels and sets the target SOC in advance to ensure sufficient battery discharge capacity will be available when fuel runs out, avoiding sudden performance restriction.
Solution Approach 2:
The patent applies continuity of useful action by ensuring continuous adequate power supply through coordinated operation of FC system and power storage. By adjusting target SOC based on fuel levels, the system maintains continuous sufficient power output throughout the fuel duration, preventing interruptions or performance restrictions.
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
This approach ensures sustained traveling performance by managing the output from both the FC system and the power storage, preventing sudden restrictions and allowing travel until the fuel is depleted to a threshold value, thereby balancing fuel and battery energy usage.
Implementation Method 1
an FC stack that generates electric power with fuel stored in the tank
Data Source
AI summary
An FCV includes an FC system and a battery. The FC system includes an FC stack and a boost converter that adjusts output from the FC stack. An FDC-ECU controls the boost converter to adjust an SOC of the battery to a target SOC while electric power is supplied from the FC stack to an inverter. Then, the FDC-ECU lowers the target SOC with decrease in remaining amount of hydrogen in a hydrogen tank.