Hybrid Vehicle Mode Transition Control Device
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Solution Overview
Problem
Conventional hybrid vehicle mode transition from series traveling mode to parallel traveling mode can cause discomfort to the driver due to significant changes in engine rotational speed.
Innovation Solution
A mode transition control device that selects an internal combustion engine gear shift stage with a rotational speed change amount less than or equal to a predetermined threshold value during the transition, using a transmission system with a first electric motor, a second electric motor, and an internal combustion engine, to minimize discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the mode transition is executed by switching from series traveling mode to parallel traveling mode, then the vehicle can utilize both motor power and engine power for driving, but the rotational speed of the internal combustion engine changes significantly causing driver discomfort
Solution Approach 1:
The control device performs preliminary actions by pre-calculating the required rotational speed of the internal combustion engine in the parallel traveling mode based on the current vehicle speed and accelerator operation. Before executing the mode transition, the system prepares the engine rotational speed to match the target speed, thereby preventing sudden changes that would cause driver discomfort while enabling seamless power source switching.
2Use of energy by moving object
If the engine rotational speed is maintained at power generation speed for the second electric motor in series traveling mode, then power can be generated for motor-driven wheels, but the rotational speed is not optimized for direct driving in parallel traveling mode
Solution Approach 1:
The system dynamically adjusts the operational characteristics of the internal combustion engine based on the traveling mode. In series traveling mode, the engine operates at power generation speed optimized for the second electric motor. When transitioning to parallel traveling mode, the control device dynamically recalculates and adjusts the engine rotational speed to the appropriate driving speed based on vehicle speed and accelerator operation, thereby optimizing driving efficiency while maintaining power generation efficiency in the previous mode.
Data Source
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AI summary
Provided is a mode transition control device for a hybrid vehicle and that reduces the sensation of discomfort that may be imparted to a driver at the time of a mode transition from a series traveling mode to a parallel traveling mode during traveling. During mode transition from a series traveling mode to a parallel traveling mode in a hybrid vehicle that is capable of mode transition between the series traveling mode and the parallel traveling mode, a gear shift stage is selected such that the rotational speed change amount ΔNE of an internal combustion engine ICE accompanying mode transition is less than or equal to a predetermined threshold value ΔNETH.