Hybrid Vehicle Mode Switching via Battery Power Threshold
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hybrid vehicles face challenges in accurately calculating mechanical power from batteries, leading to errors in mode switching from electric vehicle (EV) to hybrid electric vehicle (HEV) mode, resulting in temporary torque output shortages and deteriorated drivability due to inefficiencies in motor and load conditions.
Innovation Solution
A device comprising a measuring unit, calculation unit, and controller that calculates actual battery power consumption and switches modes from EV to HEV when consumption exceeds a threshold, preventing torque output shortages by determining the optimal time to start the engine based on power consumption and efficiency margins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the running mode is changed based on driving demand power (mechanical power), then the vehicle can respond to power demands, but calculation errors occur due to motor efficiency and load amount variations, causing temporary torque output shortages
Solution Approach 1:
The patent replaces the mechanical power calculation method (which relies on motor efficiency and load amount) with an electrical power measurement method. The controller calculates electrical power consumption based on battery voltage and current, which are directly measurable electrical parameters. This substitution eliminates the cumulative errors associated with mechanical efficiency calculations and provides more accurate real-time power consumption data for mode switching decisions.
2Reliability
If the engine start threshold is set low to prevent battery depletion, then battery protection is improved, but unnecessary engine starts occur causing increased power consumption and reduced drivability
Solution Approach 1:
The controller performs preliminary assessment of the battery's state of charge and power consumption trends before triggering engine start. By monitoring electrical power consumption over time and comparing it against threshold values, the system determines in advance whether engine start is necessary. This preliminary action prevents unnecessary engine starts while ensuring timely starts when actually needed, thus protecting battery reliability without compromising drivability.
3Productivity
If the engine start threshold is set high to avoid unnecessary starts, then drivability is maintained, but battery depletion risk increases and battery protection is compromised
Solution Approach 1:
The system implements continuous feedback monitoring of battery voltage, current, and calculated electrical power consumption. The controller compares real-time power consumption against predetermined threshold values and adjusts engine start decisions based on this feedback. This feedback mechanism ensures that the threshold is set optimally to prevent battery depletion while avoiding unnecessary engine starts, thus maintaining both drivability and battery protection.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method and device for controlling a running mode of a hybrid vehicle are provided. The method includes monitoring power consumption of a battery when the hybrid vehicle is driven in an electric vehicle (EV) mode and calculating a threshold value for starting an engine. Then, whether to change the running mode of the hybrid vehicle is determined using the power consumption of the battery and the threshold value for starting the engine.