PHEV Transmission Control for Maximizing Electric Driving
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Solution Overview
Problem
In parallel hybrid vehicles, the conflict between optimizing internal combustion engine and electric driving modes leads to unnecessary internal combustion engine starts during brief accelerations, resulting in unfavorable load points and increased exhaust gas emissions.
Innovation Solution
A method that maximizes purely electric driving by controlling the automatic transmission to maintain a minimum rotational speed above 0 to 100 rpm below the electric motor's breakpoint speed, preventing the internal combustion engine from starting during situations like urban driving, using satellite-based positioning, digital road maps, and car-to-X communication to identify ideal electric driving conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional shifting strategy optimized for internal combustion engine is used, then the rotational speed is kept at lowest possible values, but the internal combustion engine starts unnecessarily during brief accelerations in urban areas
Solution Approach 1:
The patent applies dynamics by making the shifting strategy adaptable and changeable based on operating conditions. The control system dynamically selects between different shifting strategies (conventional ICE-optimized vs. electric motor-optimized) depending on whether the vehicle is in hybrid mode with maximum electric driving objective, thereby resolving the contradiction between low rotational speed and unnecessary ICE starts
Solution Approach 2:
The patent changes the shifting strategy parameters based on the operating mode. When in hybrid mode with electric driving objective, the system modifies the shifting behavior to maintain higher rotational speeds that keep the electric motor in its optimal output range, preventing unnecessary ICE starts and reducing emissions
2Power
If the rotational speed is increased to obtain maximum output from the electric motor, then the electric driving performance is improved, but the internal combustion engine starts during accelerations
Solution Approach 1:
The system dynamically adjusts the rotational speed profile based on the driving objective. When maximum electric driving is sought, the control system maintains higher rotational speeds to keep the electric motor in its optimal output range, thereby maximizing electric motor power while avoiding ICE starts and associated emissions
3Ease of operation
If a conventional shifting strategy is used, then the system is simple to operate, but it cannot maximize purely electric driving operation in hybrid mode
Solution Approach 1:
The patent implements a universal control system that handles multiple operating modes (conventional ICE mode, hybrid mode with electric driving objective, and different driving conditions). The single control unit automatically selects the appropriate shifting strategy based on the current mode, maintaining ease of operation while maximizing electric driving proportion when in hybrid mode
Data Source
AI summary
A method for operating a motor vehicle having a hybrid drive, and to a motor vehicle configured for carrying out the method. In a hybrid operating mode of the motor vehicle, a proportion of a purely electric driving operation is maximized by controlling the automatic transmission so a resulting rotational speed is not lower than a preset minimum value.