Hybrid Vehicle SOC Keeping Control via Preliminary Charging
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Solution Overview
Problem
Existing hybrid vehicle systems face challenges in maintaining a sufficient state of charge (SOC) during the SOC keeping mode, leading to potential power shortages when switching to this mode with low SOC, which can limit motor running capabilities.
Innovation Solution
A vehicle system with an engine, motor generator, electrical storage device, keeping switch, and controller that automatically ensures a state of charge higher than or equal to a predetermined value by executing first and second keeping controls, limiting discharge power and promoting regenerative power generation when SOC is low, and prohibiting motor running until a target charge is reached.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the vehicle switches to SOC keeping mode when SOC is low, then the vehicle can prepare for future motor running, but electric power becomes short and motor running cannot be fully utilized
Solution Approach 1:
The controller executes preliminary charging action before allowing motor running. When SOC is below the threshold in keeping mode, the system automatically performs charging control to raise SOC to the threshold level before enabling motor running, ensuring sufficient electric power is available in advance
Solution Approach 2:
The controller continuously monitors SOC level and provides feedback control. When SOC drops below the threshold in keeping mode, the system detects this condition and automatically switches to charging control, adjusting power flow based on real-time SOC feedback to maintain adequate electric power levels
2Reliability
If the vehicle executes SOC recovery control to raise SOC to threshold, then electric power is ensured for future usage, but charging time and travel time increase
Solution Approach 1:
The system dynamically adjusts charging control based on real-time SOC levels. When SOC is below threshold in keeping mode, charging control is activated; when SOC reaches or exceeds the threshold, charging control is canceled. This dynamic adjustment optimizes charging time while ensuring reliable electric power availability
Solution Approach 2:
The controller changes the charging parameter (SOC threshold) as a reference point for control decisions. By comparing current SOC against this parameter threshold, the system determines when to activate or cancel charging control, enabling flexible time management while maintaining power reliability
3Ease of operation
If the vehicle allows motor running with low SOC, then travel flexibility is maintained, but power shortage occurs and limits running distance
Solution Approach 1:
The system performs preliminary SOC verification before allowing motor running. In keeping mode, the controller checks whether SOC meets the threshold requirement, and only after confirming sufficient SOC does the system enable motor running, preventing power shortage before it occurs
Solution Approach 2:
The controller provides feedback control on motor running availability based on SOC levels. When SOC is insufficient in keeping mode, the system feedback-indicates limited motor running capability; when SOC is sufficient, full motor running capability is restored, maintaining travel flexibility with adequate power
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
Ensures a stable state of charge during the SOC keeping mode, preventing power shortages and enabling extended motor running distances by controlling charge and discharge powers dynamically.
Implementation Method 1
the motor generator being configured to generate an output for causing the vehicle to travel
Implementation Method 2
the electrical storage device being configured to exchange electric power with the motor generator
Data Source
AI summary
A vehicle includes an engine, a motor generator, an electrical storage device, a keeping switch, and a controller. The controller is configured to (a) cause the vehicle to travel by using the output of at least one of the engine and the motor generator, (b) control the state of charge of the electrical storage device, (c) when the keeping mode is requested in response to the signal output from the keeping switch and when the state of charge is higher than a threshold, execute a first keeping control for keeping the state of charge at a current value, and (d) when the keeping mode is requested in response to the signal output from the keeping switch and when the state of charge is lower than the threshold, execute a second keeping control for recovering the state of charge from a current value.