Transmission Shift Hold Control for Cornering Engine Noise
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Solution Overview
Problem
Shift hold control in vehicles often results in excessive engine rotation speed during cornering, causing driver discomfort due to prolonged high engine noise.
Innovation Solution
A control device that monitors lateral acceleration and turbine rotation speed to permit upshift by one gear stage when predetermined conditions are met, such as higher turbine rotation speed and accelerator opening, to manage engine speed and reduce discomfort.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shift hold control is performed to prevent upshift during cornering, then the transmission remains in a lower gear stage, but the engine rotation speed becomes excessively increased causing driver discomfort
Solution Approach 1:
The control device changes the gear shift stage parameter from the held lower stage to a higher stage when the turbine rotation speed exceeds the threshold, thereby reducing engine rotation speed and eliminating driver discomfort while maintaining cornering stability through conditional parameter adjustment
2Object-affected harmful factors
If upshift is permitted during shift hold control, then engine rotation speed is reduced, but the transmission may shift to a higher gear stage prematurely
Solution Approach 1:
The control device uses feedback from the turbine rotation speed sensor to monitor real-time rotation speed and compares it against the threshold value, permitting upshift only when the feedback indicates excessive rotation speed, thereby achieving both noise reduction and accurate shift timing
Solution Approach 2:
The system dynamically adjusts the gear shift stage based on real-time turbine rotation speed conditions rather than maintaining a fixed held stage, allowing adaptive response to changing operational conditions while maintaining shift timing accuracy
Data Source
AI summary
A vehicle includes an engine, a torque converter, a transmission, and a control device. The torque converter is coupled to the engine. The transmission is coupled to the torque converter. The control device is configured to control operation of the transmission. The control device includes a controller configured to perform shift hold control to prevent upshift of the transmission based on a lateral acceleration value of the vehicle. The controller is configured to permit the upshift of the transmission by only one gear shift stage in a case where a predetermined condition is met in the shift hold control. The predetermined condition includes a condition that an index value indicating a rotation speed of an output shaft of the torque converter be higher than a first threshold value.