Hybrid Vehicle Control Method for Self-Driving Mode
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Solution Overview
Problem
Hybrid vehicles in self-driving mode experience frequent mode switching between electric vehicle (EV) and hybrid electric vehicle (HEV) modes, leading to increased mode-switching frequency and reduced regenerative amount, which bothers the driver and limits mode shifting from HEV to EV.
Innovation Solution
A control method that calculates a target driving force based on vehicle-speed and driver operation in manual mode, and on target and actual vehicle-speed in self-driving mode, with enlarged dead-zone widths for powering and regeneration to suppress mode-switching frequency while maintaining regenerative amount, by changing operation modes between EV and HEV modes based on target driving force shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large width of dead zone is set between the hybrid electric vehicle area and the electric vehicle area to suppress mode-switching frequency, then the mode-switching frequency is reduced, but the mode shifting from the hybrid electric vehicle mode to the electric vehicle mode is limited, reducing the regenerative amount
Solution Approach 1:
The dead zone width is made dynamic rather than fixed. The control device sets a first dead zone width when the vehicle is in manual-driving mode and a second dead zone width (larger than the first) when the vehicle is in self-driving mode. This dynamic adjustment allows the system to optimize for both stability and energy recovery under different operating conditions.
Solution Approach 2:
The system changes the parameter of dead zone width based on the driving mode. By detecting whether the vehicle is in manual-driving or self-driving mode, the control device adjusts the dead zone width parameter accordingly, allowing a larger dead zone in self-driving mode to suppress mode switching while maintaining the ability to shift to electric vehicle mode for regenerative braking.
2Device complexity
If the same dead-zone width is used for both manual-driving mode and self-driving mode, then the control logic is simple, but the mode-switching frequency increases in self-driving mode bothering the driver
Solution Approach 1:
The dead zone width is made dynamic based on the detected driving mode. The control device detects whether the vehicle is in manual-driving mode or self-driving mode and sets different dead zone widths accordingly, allowing the system to adapt to different operating conditions and suppress mode switching in self-driving mode where it would bother the driver.
Solution Approach 2:
The control device uses feedback from the driving mode detection to adjust the dead zone width. By continuously monitoring the driving mode (manual or self-driving) and adjusting the dead zone parameter in response, the system maintains appropriate mode switching behavior for each driving condition without requiring complex additional control logic.
Data Source
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AI summary
Provided is control method for hybrid vehicles capable of suppressing an increase in the frequency of mode switching while suppressing a decrease in the regenerative amount when the hybrid vehicle is set at the self-driving mode. The control method for hybrid vehicles that change an operation mode of the vehicle between HEV mode and EV mode in accordance with the size of a target drive force. When the manual-driving mode is set, the target driving force is calculated based on a vehicle-speed (VSP) and a driver's driving operation (APO), and when self-driving is set, the target driving force is calculated based on a target vehicle-speed and an actual vehicle-speed. When self-driving is set, an amount to enlarge a dead-zone width Wα to control the motor generator (MG) to perform powering relative to the dead-zone width (Wa) when the manual-driving mode is set is set larger than an amount to enlarge a dead-zone width (Wβ) to control the motor generator (MG) to perform regeneration relative to the dead-zone width (Wb) when the manual-driving mode is set.