CVT Vehicle Control Device Linear Shifting Mode
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Solution Overview
Problem
In vehicles with continuously variable transmissions, the engine revolution speed can shift from the up-shift destination in linear shifting mode due to battery charge state changes, causing discomfort to the driver during up-shifting.
Innovation Solution
A vehicle control device and method that sets a target driving force based on the engine operating state, controlling the output of the driving source and gear ratio of the continuously variable transmission, with a power generator capable of being driven by the source, where driving force control is corrected in normal mode but not in linear shifting mode, which prioritizes revolution speed change, and includes a correction mechanism to cancel SOC-based corrections during up-shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If driving force control is corrected on the basis of power generating state of the power generator, then fuel efficiency is improved, but engine revolution speed shifts from up-shift destination in linear shifting mode causing driver discomfort
Solution Approach 1:
The control device dynamically switches between two control modes: normal shifting mode (with SOC-based correction) and linear shifting mode (without correction). This dynamic adaptation allows the system to optimize fuel efficiency in normal conditions while ensuring smooth shifting and driver comfort when linear shifting is selected, resolving the contradiction between energy efficiency and operational comfort.
Solution Approach 2:
The invention changes the control parameter behavior based on operating mode. In linear shifting mode, the target engine revolution speed is held constant at the up-shift destination value regardless of SOC changes, whereas in normal mode, the target speed varies with SOC to optimize fuel efficiency. This parameter change strategy resolves the contradiction by adapting the correction application to the specific operational context.
2Productivity
If target engine revolution speed is changed in accordance with charged state of the battery, then power generation efficiency is improved, but engine revolution speed stability during up-shifting deteriorates
Solution Approach 1:
The system dynamically adjusts the application of SOC-based speed correction based on the selected shifting mode. In linear shifting mode, correction is disabled to maintain speed stability during up-shifting, while in normal mode, correction is enabled to optimize power generation efficiency. This dynamic control strategy resolves the contradiction between productivity and stability.
Solution Approach 2:
The invention applies different control qualities to different operational contexts: when linear shifting mode is active, the control system prioritizes speed stability by disabling correction; when normal mode is active, it prioritizes power generation efficiency by enabling correction. This localized quality adjustment resolves the contradiction by tailoring the control behavior to the specific operational requirement.
3Speed
If linear shifting mode is used to prioritize revolution speed change, then shifting speed is improved, but engine revolution speed shifts from up-shift destination due to SOC correction
Solution Approach 1:
The control device dynamically disables SOC-based correction when linear shifting mode is detected, preserving the accuracy of engine revolution speed at the up-shift destination while maintaining the fast shifting characteristics of linear mode. This dynamic adaptation resolves the contradiction between shifting speed and speed accuracy.
Solution Approach 2:
The system performs preliminary detection of the shifting mode and proactively disables correction before SOC changes can affect the engine revolution speed during linear shifting. This preliminary action prevents the accuracy degradation before it occurs, resolving the contradiction between fast shifting and precise speed control.
Data Source
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AI summary
A vehicle control device executes driving force control to set a target driving force in accordance with an engine operating state, and control an output of a driving source and a gear ratio of a continuously variable transmission so that a target driving force is realized. The device includes a power generator which can be driven by the driving source, and in a normal shifting mode, the driving force control is corrected on the basis of a power generating state of the power generator, and in a linear shifting mode giving priority to a revolution speed change of the driving source, the correction of the driving force control is not carried out.