Vehicular Drive Control Apparatus for Rapid Shifting Response
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Solution Overview
Problem
The existing vehicular drive systems with continuously variable and step-variable transmissions face challenges in achieving rapid shifting responses and optimal fuel economy due to the need for long shifting times and deteriorated shifting responses, especially when large changes in overall speed ratios are required.
Innovation Solution
A control apparatus that includes continuous-transmission control means with first and second shifting control means to manage the speed ratios of the continuously variable transmission, allowing for independent control to prevent engine speed changes during shifting actions, enabling step-wise changes in overall speed ratios and reducing shifting shock, while maintaining fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the overall speed ratio is changed continuously to maintain optimal engine operation, then fuel economy is improved, but shifting response deteriorates and shifting time increases
Solution Approach 1:
The patent segments the speed ratio control into two independent control systems: a step-variable transmission portion that provides discrete gear positions for rapid shifting, and a continuously-variable transmission portion that enables continuous speed ratio adjustment within each gear position. This segmentation allows the system to switch between step-wise shifting (for rapid response) and continuous adjustment (for fuel economy), resolving the contradiction between shifting speed and fuel efficiency.
2Stability of the object's composition
If the speed ratio of the continuously-variable transmission is adjusted to compensate for input speed changes during shifting, then engine speed stability is maintained, but shifting response becomes slow
Solution Approach 1:
The patent implements dynamic control mode switching between two shifting control portions: the first shifting control portion actively adjusts the continuously-variable transmission ratio to compensate for input speed changes and maintain engine speed stability, while the second shifting control portion disables this compensation to enable rapid step-wise shifting. The system dynamically selects the appropriate control mode based on driving conditions, allowing both stable engine operation and fast shifting when needed.
Data Source
AI summary
A control apparatus for a vehicular drive system provided with a continuously-variable transmission portion operable as an electrically controlled continuously variable transmission, and a step-variable transmission portion, the continuously-variable transmission portion having a differential mechanism operable to distribute an output of an engine to a first electric motor and a power transmitting member, and a second electric motor disposed in a power transmitting path between the power transmitting member and a drive wheel of a vehicle, the control apparatus including a continuous-transmission control device including a first shifting control portion for controlling a speed ratio of the continuously-variable transmission portion, so as to prevent a change of a speed of the engine due to a change of an input speed of the step-variable transmission portion upon a shifting action of the step-variable transmission portion, and second shifting control portion for controlling the speed ratio of the continuously-variable transmission portion independently of the shifting action of the step-variable transmission portion, the continuous-transmission control means selectively activating the first shifting control portion and the second shifting control portion, on the basis of a manner in which an overall speed ratio of the transmission mechanism is changed.