Hybrid Vehicle Engine Control for Battery Charging Comfort
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Series hybrid vehicles experience a sudden feeling of engine driving due to engine operation independent of driver input, causing discomfort when battery charge levels decrease.
Innovation Solution
Implementing a hybrid vehicle control method that adjusts engine rotation speed based on battery charge thresholds, driving the engine at a low first rotation speed when the charge falls below a certain level and increasing to a higher second rotation speed only when necessary, while continuing to drive until the charge reaches a sufficient level, and then stopping the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the engine is driven regardless of accelerator operation to charge the battery when residual amount decreases, then the battery charging amount is improved, but the driver experiences a sudden feeling from engine driving
Solution Approach 1:
The engine control system dynamically adjusts engine operation based on battery state of charge levels. When SOC is between threshold1 and threshold2, the engine operates at a first rotation speed that generates acceptable charging current while minimizing sudden driving feelings. When SOC drops below threshold2, the engine increases to a second rotation speed for faster charging. This dynamic adjustment resolves the contradiction by adapting engine behavior to real-time battery needs while considering driver comfort.
Solution Approach 2:
The system changes engine rotation speed as a parameter based on battery SOC levels. By establishing multiple rotation speed modes (first rotation speed for moderate charging, second rotation speed for intensive charging), the system can adjust the charging parameter according to battery state. This parameter change approach allows the engine to provide necessary charging current while selecting operation modes that reduce sudden driving feelings when possible.
2Productivity
If the engine rotation speed is increased to charge the battery faster, then the charging efficiency is improved, but the engine driving sound becomes more sudden and noticeable
Solution Approach 1:
The engine control system dynamically selects rotation speed based on real-time battery SOC levels rather than operating at a fixed high speed. When battery charge levels are sufficient (SOC > threshold2), the engine operates at the lower first rotation speed, reducing charging efficiency but minimizing sudden driving sounds. When battery charge becomes critical (SOC ≤ threshold2), the system transitions to the higher second rotation speed to maximize charging efficiency. This dynamic approach balances productivity and noise reduction based on actual battery needs.
Solution Approach 2:
The engine operates in periodic cycles between two rotation speed modes based on battery charge thresholds. The system alternates between the first rotation speed (lower noise, moderate charging) and second rotation speed (higher noise, intensive charging) according to battery SOC levels. This periodic action pattern allows the engine to provide intensive charging only when necessary, reducing overall sudden driving sounds while maintaining adequate charging efficiency when battery levels are critical.
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 the frequency and intensity of high engine rotation speed operations, minimizing sudden engine sounds and enhancing driver comfort by optimizing engine operation based on battery charge levels.
Implementation Method 1
a generator (2) and a battery (3), the generator (2) being connected to the engine (1) and configured to generate electric power by use of power of the engine (1), and the battery (3) being connected to the generator (2) and configured to store the electric power generated by the generator (2)
Implementation Method 2
an electric motor (4) and driving wheels (7), the electric motor (4) being connected to the battery (3) and configured to generate a driving force for the driving wheels (7) by use of electric power of the battery (3)
Data Source
AI summary
A control method for a hybrid vehicle includes a generator and an electric motor, the generator being configured to charge a battery by use of power of an engine, the electric motor being configured to drive driving wheels by electric power of the battery. The control method having driving the engine at a first rotation speed when a charging amount of the battery decreases to a first charging threshold; changing the engine to driving at a second rotation speed larger than the first rotation speed when the engine is driven at the first rotation speed and the charging amount decreases to a second charging threshold smaller than the first charging threshold; and continuing driving of the engine until the charging amount becomes equal to or more than a charging end threshold larger than the first charging threshold.