Series Hybrid Engine-Generator Control for Low-Temperature Battery Charging
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Solution Overview
Problem
In series hybrid vehicles, the battery may not be charged effectively during idling operations, especially in low-temperature environments, leading to a risk of power depletion due to continuous power consumption by the drive motor and auxiliary components.
Innovation Solution
A control method that calculates a drive torque target value based on battery state and required electric power, controlling the electric generator and engine rotation speed to perform low electric power generation, ensuring the battery is charged and power is secured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the engine performs idling operation to warm up the battery in low-temperature environment, then the battery temperature increases, but the battery cannot be charged effectively and SOC continues to decrease
Solution Approach 1:
The patent dynamically adjusts engine rotation speed based on battery temperature and SOC conditions. When battery temperature is low and SOC is decreasing, the engine rotation speed is increased above the standard idle speed to enable the electric generator to produce electricity and charge the battery, thus dynamically resolving the contradiction between warming up the battery and charging it.
Solution Approach 2:
The engine during idle operation serves multiple functions: warming up the battery (thermal function) and generating electricity through the electric generator to charge the battery (energy storage function). By making the idle operation multi-functional, the patent simultaneously addresses both temperature increase and charge maintenance.
2Quantity of substance
If the engine rotation speed is increased to generate electric power through the electric generator, then the battery can be charged, but the fuel consumption increases
Solution Approach 1:
The patent changes the engine rotation speed parameter from standard idle speed to a higher value when specific conditions (low battery temperature and decreasing SOC) are detected. This parameter change enables the electric generator to produce sufficient electricity for charging the battery while minimizing fuel consumption by only increasing speed when necessary.
Solution Approach 2:
The system monitors its own state (battery temperature and SOC) and automatically adjusts engine operation to charge the battery when needed, making the system self-regulating and avoiding unnecessary fuel consumption during periods when charging is not required.
3Temperature
If the engine performs prolonged idling operation in low-temperature environment, then the battery can be warmed up, but the SOC continues to decrease due to power consumption
Solution Approach 1:
The patent implements a feedback control mechanism that continuously monitors battery temperature and SOC levels. When SOC decreases below a threshold during idle operation, the system responds by increasing engine rotation speed to generate electricity and charge the battery, thus maintaining power availability while continuing the warming process.
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 method secures the required electric power for vehicle operation and auxiliary components, reducing the risk of power depletion by maintaining a sufficient State of Charge (SOC) in the battery, even in low-temperature conditions.
Implementation Method 1
an electric generator, an engine coupled to the electric generator... electric power generated by the electric generator being configured to be supplied to at least one of the battery and the drive motor
Data Source
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AI summary
This is a control method for a vehicle, the vehicle including an electric generator, an engine coupled to the electric generator, a drive motor configured to drive the vehicle, and a battery electrically connected to the electric generator and the drive motor, electric power generated by the electric generator being configured to be supplied to at least one of the battery and the drive motor. The control method is including: calculating, when a temperature of the battery is equal to or lower than a predetermined temperature, a drive torque target value based on required electric power of the vehicle and a state of the battery, controlling a torque of the electric generator based on the drive torque target value, and controlling a rotation speed of the engine based on a predetermined reference low rotation speed, thereby performing a low electric power generation control for causing the electric generator to generate electric power.