AMT Shift Actuator Torque Control
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Solution Overview
Problem
Existing automated manual transmissions (AMTs) face inefficiencies in gear shifting due to the need to disengage the clutch, leading to longer shift times and increased load on the transmission components.
Innovation Solution
A vehicle drive system that includes a transmission with idler gears and fixed gears, a connecting portion to restrain idler gears from rotating, and a shift actuator that gradually decreases engine torque while the clutch remains engaged during gear shifts, allowing for faster and smoother transitions between gear stages without fully disengaging the clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clutch is disengaged before establishing neutral state during gear shift, then the load on transmission components is reduced to zero, but the shift time increases due to additional clutch disengagement and engagement processes
Solution Approach 1:
The system performs preliminary torque reduction by the shift actuator before the clutch is fully disengaged. The connecting portion moves to establish neutral state while the clutch is still partially engaged, preparing the transmission for gear change without waiting for complete clutch disengagement. This preliminary action reduces the time required for the overall shift process.
Solution Approach 2:
The clutch remains continuously engaged throughout the gear shift process, eliminating the stoppage that occurs during complete disengagement and re-engagement. The torque is gradually reduced and then restored, maintaining continuous power transmission capability while still allowing the connecting portion to move between gear stages. This continuous action eliminates the time loss associated with clutch disengagement and engagement cycles.
2Loss of time
If the clutch remains engaged during gear shift, then the shift time is reduced, but the frictional resistance and load on transmission components increases
Solution Approach 1:
The system dynamically changes the torque parameter during the gear shift process. The shift actuator gradually reduces the engine torque transmitted through the clutch while the connecting portion moves to the neutral position. This parameter change allows the clutch to remain engaged (maintaining continuity) while reducing the frictional resistance and load on transmission components to acceptable levels during the shift operation.
Data Source
AI summary
A vehicle drive system includes a transmission, a clutch, and a shift execution portion. The shift execution portion operates the shift actuator to control the connecting portion in an engaged state engaged with the idler gear of a present gear stage to disengage from the idler gear of the present gear stage while gradually decreasing the engine torque while the clutch is still engaged, when a shift operation from the present gear stage to a subsequent gear stage is executed.