Series Hybrid B-Range Control to Preserve Regenerative Deceleration
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Solution Overview
Problem
In series hybrid vehicles, fully charging the battery in ranges with high deceleration magnitude limits regenerative braking, reducing deceleration and potentially causing driver discomfort.
Innovation Solution
Implementing a control method that initiates pre-motoring in the B range at a lower state of charge than in the D range, preventing battery full charge and maintaining higher deceleration levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If regenerative braking is limited when the battery becomes fully charged in the B range, then the battery charging is suppressed, but the magnitude of deceleration is reduced causing driver discomfort
Solution Approach 1:
The system initiates pre-motoring operation before the battery reaches full charge state. By detecting that the battery SOC has reached a predetermined threshold value, the control device starts the internal combustion engine to generate electric power in advance, preventing the battery from becoming fully charged and avoiding the need to limit regenerative braking, thus maintaining high deceleration performance throughout the B range.
Solution Approach 2:
The control system dynamically switches between different operating modes (EV mode, charge mode, pre-motoring mode) based on real-time battery SOC levels and driving conditions. This dynamic control allows the system to optimize the balance between battery charging and deceleration performance, ensuring that regenerative braking is not limited while preventing battery overcharge through timely pre-motoring intervention.
2Reliability
If the battery is fully charged in the B range, then charging is suppressed, but this creates driver discomfort due to reduced deceleration
Solution Approach 1:
The control device implements pre-motoring operation that starts before the battery reaches full charge. By monitoring battery SOC and initiating engine-driven electric power generation when SOC reaches a predetermined threshold, the system prevents battery overcharge in advance, thereby avoiding the need to suppress regenerative braking and eliminating the source of driver discomfort.
Solution Approach 2:
The system converts the potential harmful effect of battery full charge (which would require limiting regenerative braking) into a beneficial outcome by implementing pre-motoring. The internal combustion engine is used to generate electric power that charges the battery in a controlled manner, transforming what would be a problematic situation into an opportunity to maintain both battery management and deceleration performance.
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 minimizes battery charging through limited regeneration, maintains higher deceleration levels, and prevents driver discomfort due to reduced deceleration.
Implementation Method 1
deceleration produced by regenerative braking of a drive motor (4) is greater in a B range than in a D range
Implementation Method 2
a battery (5) charged with electric power from an electric power generation motor (3) that generates electric power by being driven by a drive power of an internal combustion engine (2)
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A control method for a series hybrid vehicle is used in a vehicle 1 that has a D range and a B range, a battery 5 charged with the electric power from an electric power generating motor 3 that generates electric power by being driven by the drive power from an internal combustion engine 2 and with the electric power regenerated by a drive motor 4, drive wheels 6 driven by a drive motor 4 using the electric power from the battery 5, and the deceleration generated by regenerative braking of the drive motor 4 is greater in the B range than in the D range. The control method for a series hybrid vehicle comprises initiating motoring of the internal combustion engine 2 at an SOC of the battery 5 that is lower in the B range than in the D range.