Vehicle Cabin Heating Control with Pulsed DC/DC Converter Current
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Solution Overview
Problem
In hybrid electric vehicles, existing vehicle air conditioning control systems face challenges in heating the vehicle compartment efficiently without increasing the size or cost of the DC/DC converter, especially when the engine temperature is low, as PTC heaters consume significant power and require high electric currents.
Innovation Solution
A vehicle air conditioning control system that includes an electric heater, a DC/DC converter capable of switching between steady-state and short-time currents, and a controller that adjusts the operating state of the electric heater based on engine temperature, allowing the electric heater to operate during low engine temperatures without increasing the converter's size or cost by using a short-time current for heating assistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a PTC heater is used as a heat source for heating in hybrid electric vehicles, then heating capability is improved, but the DC/DC converter size and cost increase due to high current requirements
Solution Approach 1:
The patent applies periodic action by controlling the PTC heater to operate in intermittent cycles rather than continuously. The control unit activates the heater only when engine temperature is below a predetermined threshold, creating periodic heating cycles that reduce average current consumption while maintaining adequate heating capability.
Solution Approach 2:
The patent changes the operational parameters of the PTC heater by adjusting its duty cycle and activation conditions based on engine temperature. By monitoring engine temperature and controlling heater activation accordingly, the system optimizes the balance between heating performance and current consumption, allowing for a smaller DC/DC converter.
2Temperature
If a PTC heater is used as a heat source for heating in hybrid electric vehicles, then heating capability is improved, but the DC/DC converter cost increases due to high current requirements
Solution Approach 1:
The control unit implements periodic heating cycles by activating the PTC heater only when necessary (when engine temperature is below the threshold), reducing the average current demand and allowing for a more cost-effective DC/DC converter design.
Solution Approach 2:
By changing the operational parameters to use intermittent heating based on temperature conditions, the system reduces the peak and average current requirements, enabling the use of a smaller, less expensive DC/DC converter while maintaining heating capability.
3Temperature
If the electric heater operates continuously to maintain comfortable temperatures, then heating effectiveness is improved, but energy consumption increases
Solution Approach 1:
The system employs feedback control by continuously monitoring engine temperature and using this information to control PTC heater activation. The control unit adjusts heater operation based on real-time temperature data, ensuring the heater operates only when needed to maintain comfortable cabin temperatures, thereby optimizing energy consumption.
Solution Approach 2:
The heater operates in periodic cycles triggered by temperature conditions rather than continuously. This intermittent operation based on feedback from temperature sensors reduces overall energy consumption while maintaining heating effectiveness when required.
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 solution enables efficient heating of the vehicle compartment using the electric heater without increasing the size or cost of the DC/DC converter, effectively assisting existing heating equipment and maintaining comfortable temperatures by switching the electric heater's state and current output based on engine temperature.
Implementation Method 1
The electric heater is configured to apply heat to an air conditioning airflow to be blown out into a space in a vehicle compartment
Implementation Method 2
The direct-current-to-direct-current converter is configured to convert a voltage of electric power of an in-vehicle battery into a predetermined voltage
Data Source
AI summary
A vehicle air conditioning control system includes an electric heater, a direct-current-to-direct-current converter, an engine system temperature sensor, and a controller. The electric heater applies heat to an air conditioning airflow. The direct-current-to-direct-current converter converts a voltage of electric power of an in-vehicle battery. The engine system temperature sensor measures a temperature of one or each of an engine and a related member. The controller controls an operating state of the electric heater based on the temperature. Upon determining, based on the temperature, that the electric heater is to operate, the controller performs a control of switching the operating state between: an operating state where the electric heater is turned on and the direct-current-to-direct-current converter is caused to output a short-time current; and an operating state where the electric heater is turned off and the direct-current-to-direct-current converter is caused to output a steady-state current.