PHEV Engine Power Control for CD Mode Heating
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Solution Overview
Problem
In plug-in hybrid electric vehicles (PHEVs) without a high voltage positive temperature coefficient (PTC) heater, engine power control during charge depleting (CD) mode heating is not optimized for fuel efficiency, as existing controls are based on state of charge (SOC) rather than the required heat amount, leading to suboptimal heating performance.
Innovation Solution
A method to control engine power during CD mode heating by using an engine power map that considers the level of the air-conditioning blower, outdoor air temperature, and coolant temperature, dividing the engine power into high-stage, intermediate-stage, and low-stage maps to adjust power according to heating demands, ensuring optimal engine operation for improved fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engine power is controlled based on state of charge (SOC) to prevent overcharge, then overcharge prevention is achieved, but fuel efficiency deteriorates because the control does not account for actual heating requirements
Solution Approach 1:
The control method changes the parameter basis from SOC to actual heating requirements by introducing a heat requirement calculation that considers blower motor speed, outdoor temperature, and coolant temperature. This allows engine power to be adjusted according to actual thermal needs rather than battery charge state, improving fuel efficiency while maintaining reliable heating operation.
2Reliability
If minimum engine power is selected to prevent overcharge during CD mode, then overcharge prevention is achieved, but heating performance deteriorates because the engine power is insufficient for optimal heating
Solution Approach 1:
The control system dynamically adjusts engine power based on real-time heating requirements by continuously monitoring blower motor speed, outdoor temperature, and coolant temperature. This dynamic adjustment allows the engine to operate at optimal power levels for heating while preventing overcharge through coordinated battery management, resolving the contradiction between heating performance and overcharge prevention.
3Temperature
If engine power is increased to meet heating demands rapidly, then heating performance is improved, but fuel consumption increases
Solution Approach 1:
The control method implements feedback by continuously monitoring heating system parameters (blower motor speed, outdoor temperature, coolant temperature) and adjusting engine power accordingly. This feedback mechanism ensures the engine operates at the minimum necessary power level to meet heating demands, avoiding excessive fuel consumption while maintaining adequate heating performance.
Data Source
AI summary
In a method for controlling engine power during charge depleting (CD) mode heating of a plug-in hybrid electric vehicle (PHEV), the engine power is controlled according to an amount of heat of an engine required for heating determined using a level of an air-conditioning blower at a point in time at which an operation of the engine starts, an outdoor air temperature, and a coolant temperature, if a full automatic temperature controller (FATC) operates the engine for heating when the vehicle is driven in a CD mode.