Hybrid EV Engine Control for Fewer Restarts in CS Mode
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Solution Overview
Problem
Existing engine control technologies in electric vehicles (EVs) face inefficiencies when switching from charge depleting (CD) to charge sustaining (CS) mode, leading to reduced fuel efficiency and increased engine restarts due to inadequate consideration of battery charging/discharging and lack of optimized engine control strategies.
Innovation Solution
A vehicle control system that optimizes engine ON/OFF times by using an input unit to receive power data and a controller to execute engine control strategies, including switching to CS mode, holding the engine on during low power demand, and using various control methods to minimize engine restarts and improve fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the engine is automatically switched from CD mode to CS mode to minimize power consumption, then the EV mode travel distance and time are extended, but the fuel efficiency is not optimized due to lack of battery charging/discharging consideration
Solution Approach 1:
The system dynamically changes operating parameters by switching between CD and CS modes based on battery state of charge (SOC) levels. When SOC drops below a threshold, the system transitions to CS mode with engine-on holding control to recharge the battery, optimizing both travel range and fuel efficiency through parameter-based mode transitions.
Solution Approach 2:
The control system continuously monitors battery SOC and uses this feedback to determine when to switch between CD and CS modes. The engine-on holding control activates when battery charging is needed, creating a closed-loop feedback mechanism that optimizes fuel efficiency while maintaining extended EV mode capability.
2Ease of operation
If the engine on is not held during CS mode, then the system responds quickly to power demand changes, but the engine efficiency becomes lowered due to frequent on/off cycling
Solution Approach 1:
The system performs preliminary action by proactively holding the engine on before power demand actually requires it. When entering CS mode, the engine is maintained in an on state in advance, preventing frequent restarts and improving engine efficiency while still being ready to meet power demands immediately.
Solution Approach 2:
The engine-on holding control ensures continuous useful action by maintaining the engine in an on state during CS mode operations. This continuity prevents the harmful on/off cycling that reduces engine efficiency, while the engine remains available to meet varying power demands without interruption.
3Duration of action of moving object
If the engine off control is activated easily during acceleration, then the system reduces engine running time, but the fuel efficiency worsens due to repetition of engine on/off events
Solution Approach 1:
The system applies dynamic control by adjusting engine-on holding duration based on driving conditions. During acceleration operations, the control adapts to prevent easy engine-off events that would cause frequent restarts, while still maintaining appropriate engine-off control during steady-state conditions to minimize unnecessary running time.
Solution Approach 2:
The control system applies preliminary anti-action by preventing engine-off events before they occur during acceleration. When acceleration is detected, the system proactively maintains engine-on status, counteracting the tendency for easy engine-off control that would lead to frequent restarts and reduced fuel efficiency.
Data Source
AI summary
A method can be used for controlling for engine running. An input unit receives required power data. A controller executes one among a first control for running an engine, a second control for keeping on running the engine, and a third control for stopping the engine, according to the required power data, to drive the engine. The battery is discharged or charged under control of the controller.