Vehicle Control Device Torque Phase Timing for Input Shaft Speed
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Solution Overview
Problem
Jump gear shifts in automatic transmissions involving intermediate stages often result in rapid changes in input shaft rotation speed due to hydraulic response delays and clutch torque issues, leading to degradation in drivability.
Innovation Solution
Implementing a control device with an electronic control unit that performs torque phase control with specific timing adjustments during intermediate gear shifts, switching between engagement and disengagement elements to manage clutch torque and prevent rapid rotation speed changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a jump gear shift via an intermediate shift stage is performed, then clutch heat quantity is decreased, but input shaft rotation speed changes rapidly causing degradation in drivability
Solution Approach 1:
The electronic control unit performs torque phase control in advance during the gear shift process. By controlling the torque phase time to be shorter than a predetermined value when input switching control is performed, the disengagement-side frictional engagement element is replaced early, preventing rapid input shaft rotation speed changes before they can occur
Solution Approach 2:
The control device changes the torque phase control time parameter dynamically. When input switching control is detected during intermediate shift stage gear shifts, the torque phase control time is set to be shorter than the predetermined torque phase control time, optimizing the control parameter to prevent both rapid speed changes and excessive clutch heat generation
2Reliability
If torque phase control time is extended, then disengagement-side element replacement is more complete, but gear shift duration increases causing delay
Solution Approach 1:
The torque phase control time is dynamically adjusted based on the gear shift scenario. When input switching control is performed through an intermediate shift stage, the torque phase control time is set to be shorter than the predetermined value, achieving optimal balance between disengagement completeness and gear shift speed
Data Source
AI summary
When a power-on downshift via an intermediate shift stage accompanied by input switching control is required and a predetermined shift stage is a shift stage lower than the intermediate shift stage, an electronic control unit performs torque phase control in a torque phase control time shorter than the torque phase control time that is set when the predetermined shift stage is a shift stage higher than the intermediate shift stage. Accordingly, it is possible to complete disengagement of a disengagement-side element early and to suppress a rapid increase of an input shaft rotation speed due to a clutch torque remaining.