Hybrid Vehicle Battery Thermal Management via Engine Generator Activation
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Solution Overview
Problem
Hybrid electric vehicles face challenges in managing battery temperature to prevent degradation while maintaining fuel efficiency, as existing methods either reduce vehicle performance or lead to unnecessary engine activation and fuel inefficiency.
Innovation Solution
A control apparatus that includes a temperature detector, a temperature increase rate calculator, and an engine controller to start the engine and adjust electric power generation based on battery temperature, with higher temperatures triggering earlier engine activation and increased power generation to manage temperature increases effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the electric current supplied to the motor from the battery is suppressed when battery temperature is high, then battery temperature increase is suppressed, but vehicle traveling performance deteriorates
Solution Approach 1:
The system performs preliminary action by calculating the temperature increase rate and predicting future battery temperature trends before excessive heating occurs. This allows proactive engine activation to generate electricity and cool the battery, preventing the need for reactive torque suppression that would harm vehicle performance.
2Temperature
If the engine is started to activate the generator when battery temperature is high, then battery temperature increase is suppressed, but fuel efficiency deteriorates due to unnecessary engine activation
Solution Approach 1:
The system implements feedback control by continuously monitoring battery temperature and calculating temperature increase rates, then using this information to dynamically adjust engine activation decisions. The engine control unit receives feedback from the temperature detection system and adjusts generator output accordingly, ensuring the engine runs only when necessary and at optimal power levels to balance battery cooling with fuel efficiency.
Solution Approach 2:
The system applies dynamics by making the engine activation threshold dynamic rather than fixed. The threshold value changes based on the calculated temperature increase rate and current battery temperature, allowing the system to adapt to varying thermal conditions. This dynamic adjustment ensures the engine is activated only when the thermal situation warrants intervention, optimizing the balance between battery protection and fuel consumption.
Data Source
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AI summary
A control apparatus for a hybrid electric vehicle, includes: a temperature detector configured to detect a temperature of the battery; a temperature increase rate calculator configured to calculate, based on the detected temperature of the battery, a temperature increase rate that is an amount of increase in the temperature per unit time; and an engine controller configured to allow, when the temperature increase rate is equal to or higher than a threshold value, the engine to be started, so that the generator generates the electric power. The threshold value is set so that the higher the detected battery temperature, the lower the threshold value.