Vehicle Transmission Control System Torque Synchronization
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Solution Overview
Problem
Conventional transmission control systems experience transmission shocks when shifting up due to differences in rotation speeds between engines and transmissions, leading to inefficient shifting and a poor driving experience.
Innovation Solution
A transmission control system that adjusts engine torque and clutch engagement torque to match energy levels, allowing for smooth shifting by disconnecting the clutch during gear position changes and reconnecting it with increasing torque to synchronize engine and transmission speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the clutch is connected while the engine torque is returned after up-shifting, then the transmission shock is reduced, but the time required for the torque return process is extended
Solution Approach 1:
The controller disconnects the clutch before completing the torque return process. By performing the clutch disconnection in advance, the system allows the torque to be returned without the clutch being engaged, thereby preventing transmission shock while avoiding the time penalty of a prolonged torque return process with clutch engagement.
Solution Approach 2:
The shifting process is divided into distinct phases: a first period where the clutch is disconnected and torque is reduced, and a second period where the clutch is reconnected and torque is returned. This segmentation allows the torque return operation to be performed independently of clutch engagement, resolving the contradiction between shock prevention and time efficiency.
2Productivity
If the clutch is kept connected during engine torque adjustment, then the transmission can maintain power delivery, but transmission shocks occur due to rotation speed differences
Solution Approach 1:
The clutch is temporarily disconnected from the power transmission path during the torque adjustment period. By extracting the clutch from the engagement state, the system eliminates the harmful interaction between engine torque changes and transmission rotation speed differences, preventing shocks while allowing torque to be adjusted safely.
Solution Approach 2:
The clutch is disconnected before torque adjustment begins, and reconnected after torque adjustment is complete. This preliminary disconnection action prevents the transmission shock that would occur if torque adjustment were performed with the clutch engaged, while minimizing the interruption to power delivery.
Data Source
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AI summary
In a transmission control system for a vehicle, in a torque return period at the time of up-shifting of a transmission, an engine torque and a clutch torque are increased in parallel. A target engine torque value and a target clutch torque value are set such that the clutch torque changes at a value higher than the engine torque. The target clutch torque value is set such that a difference between an amount of energy generated in a clutch and an amount of energy generated in an engine substantially coincides with an amount of energy required to reduce the rotation speed of the engine to a target rotation speed.