Fuel Cell Vehicle Torque Control During Activation
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Solution Overview
Problem
Fuel cell vehicles experience discomfort for drivers due to sudden increases in output torque when the fuel cell is activated, as the maximum output torque of the battery is smaller than the fuel cell, leading to an uncomfortable driving experience.
Innovation Solution
A controller sets a maximum increase rate for the electric motor's output torque after fuel cell activation, initially limiting it to a first upper limit rate for a predetermined time, then increasing it to a second upper limit rate, which is larger, to gradually increase torque and reduce driver discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the fuel cell is activated to increase the maximum output torque, then the power output is improved, but the driver experiences discomfort due to sudden torque increase
Solution Approach 1:
The controller detects fuel cell activation in advance and proactively limits the output torque increase rate to a first upper limit rate during the activation period. This preliminary action prevents the sudden torque jump that would cause driver discomfort, while still allowing the fuel cell to activate and eventually provide its full power capability.
Solution Approach 2:
The controller dynamically adjusts the output torque increase rate based on the fuel cell activation state. During fuel cell activation, it applies a stricter first upper limit rate, and after activation completes, it transitions to a more relaxed second upper limit rate. This dynamic adjustment optimizes both power delivery and driver comfort throughout the activation process.
2Object-affected harmful factors
If the maximum increase rate of output torque is limited during fuel cell activation, then driver discomfort is reduced, but the time to reach maximum power output increases
Solution Approach 1:
The controller implements dynamic rate adjustment by switching from the first upper limit rate to the second upper limit rate after fuel cell activation completes. This allows the system to prioritize comfort during activation while maximizing power delivery speed afterward, effectively balancing the time-tradeoff without permanently limiting power output.
Solution Approach 2:
The controller changes the torque increase rate parameter based on the fuel cell activation state. By using a first upper limit rate during activation and a second upper limit rate afterward, the system optimizes the balance between driver comfort and power delivery speed, ensuring that the total time to reach maximum power is minimized while avoiding discomfort.
Data Source
AI summary
A fuel cell vehicle includes a battery and a fuel cell that supply an electric power to an electric motor for traveling. A controller sets a maximum increase rate of an output torque of the electric motor for a predetermined time after the fuel cell starts activation to be a first upper limit rate. The controller sets the maximum increase rate of an output torque after the lapse of the predetermined time to a second upper limit rate that is larger than the first upper limit rate.