Vehicular HVAC Electric Heater Control for Battery Efficiency
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Solution Overview
Problem
The high power consumption of positive temperature coefficient (PTC) heaters in electric vehicles and hybrid vehicles leads to increased battery discharge, reducing battery efficiency and all-electric range (AER) when battery efficiency is lower than a threshold value, particularly during conditions of low battery temperature, low state of charge, and high discharge current.
Innovation Solution
A method to control the electric heater in a vehicular HVAC system by turning it off when battery efficiency drops below a threshold, considering ambient and battery temperatures, discharge currents, and state of charge, and adjusting operation based on heating conditions to maintain efficient battery use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the PTC heater operates to heat the air in the HVAC system, then the heating function is improved, but the battery discharge increases and battery efficiency deteriorates
Solution Approach 1:
The control method dynamically adjusts the PTC heater operation parameters (on/off state, duty cycle) based on real-time battery condition parameters (temperature, state of charge, discharge amount) to optimize the balance between heating performance and battery efficiency
Solution Approach 2:
The system continuously monitors battery conditions (temperature, state of charge, discharge amount) and uses this feedback to control the PTC heater operation, creating a closed-loop control system that adapts to changing battery states
2Speed
If the PTC heater operates at high power to quickly heat the passenger compartment, then the heating speed is improved, but the all-electric range (AER) is reduced
Solution Approach 1:
The control method dynamically adjusts the PTC heater power output based on real-time battery conditions, transitioning from static to dynamic control to optimize the balance between heating speed and energy conservation
Solution Approach 2:
The system applies partial heating action (reduced duty cycle or intermittent operation) when battery conditions are poor, sacrificing some heating speed to preserve battery efficiency and extend AER
3Temperature
If the PTC heater operates when battery temperature is low, then the heating function is maintained, but the battery efficiency rapidly degrades
Solution Approach 1:
The control method applies different control strategies to different battery temperature regions, using temperature-based conditional control to protect the battery from inefficient operation in low-temperature zones
4Temperature
If the PTC heater operates when state of charge is low, then the heating demand is met, but the discharge amount increases excessively
Solution Approach 1:
The system uses state of charge feedback to control PTC heater operation, preventing excessive discharge by monitoring and responding to battery charge levels in real-time
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 reduces battery discharge and maximizes battery efficiency, improving energy efficiency and extending the all-electric range (AER) of the vehicle by optimizing heater usage based on battery conditions.
Implementation Method 1
As electric energy is applied to the PTC heater, the PTC heater may generate heat
Data Source
AI summary
A method for controlling an electric heater of a vehicular heating, ventilation, and air conditioning (HVAC) system includes turning on the electric heater; determining whether an ambient air temperature of a vehicle is higher than or equal to a threshold ambient air temperature, and a battery temperature is lower than or equal to a threshold battery temperature; determining whether battery efficiency is lower than or equal to threshold efficiency when the ambient air temperature of the vehicle is higher than or equal to the threshold ambient air temperature, and the battery temperature is lower than or equal to the threshold battery temperature; and turning off the electric heater when the battery efficiency is lower than or equal to the threshold efficiency, wherein the electric heater is configured to receive electric energy from the battery.