DCT Upshift Torque Control for Faster Acceleration Feel
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Solution Overview
Problem
General dual-clutch transmission (DCT) vehicles prioritize smooth gear shifts, failing to provide users with the desired fast speed change and acceleration feeling during power-on upshifts.
Innovation Solution
A shift control method for DCT vehicles that includes a torque phase with gradually increasing coupling-side clutch torque and releasing the release-side clutch torque, synchronized with engine torque, and an inertia phase where coupling-side clutch torque is increased to synchronize engine and clutch speeds, enhanced by a push feel torque in high performance mode for faster acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If general DCT vehicles perform shift control to minimize gear shift impact, then smooth speed change feeling is achieved, but fast speed change feeling and fast acceleration feeling are not provided
Solution Approach 1:
The patent applies dynamics by making the clutch torque control strategy adaptable and changeable based on driving conditions. The controller dynamically adjusts the clutch torque profile during shift phases (torque phase, inertia phase, completion phase) according to the selected driving mode (comfortable vs. sporty), enabling the system to optimize between smoothness and speedness in real-time
Solution Approach 2:
The patent changes key control parameters including clutch torque magnitude, torque phase duration, and synchronization timing based on the driving mode selection. In sporty mode, the system modifies parameters to achieve faster speed change by adjusting the torque transfer characteristics and reducing the duration of torque-limited phases
2Power
If coupling-side clutch torque is gradually increased to target torque in torque phase, then acceleration feeling is improved, but shift control complexity increases
Solution Approach 1:
The patent segments the gear shift process into three distinct phases: torque phase (where coupling-side clutch torque is gradually increased to target torque), inertia phase (where synchronization occurs), and completion phase. This segmentation allows each phase to be controlled with specific torque profiles, improving acceleration capability while maintaining manageable control complexity through structured phase-based control
Solution Approach 2:
The patent applies preliminary action by pre-determining the target coupling-side clutch torque value before the shift begins. The target torque is calculated based on engine torque and push feel torque, allowing the control system to plan the entire torque transfer trajectory in advance, which simplifies real-time control while achieving strong acceleration
3Stability of the object's composition
If engine speed is synchronized with coupling-side clutch speed during inertia phase, then shift smoothness is improved, but shift time increases
Solution Approach 1:
The patent applies partial action by not requiring complete speed synchronization before initiating torque transfer. The system allows the inertia phase to proceed with partial synchronization, and the coupling-side clutch torque is gradually increased while tracing engine torque. This approach achieves sufficient synchronization for smooth shifting without waiting for complete speed matching, reducing overall shift time
Solution Approach 2:
The patent maintains continuity of useful action by overlapping the torque phase and inertia phase. While speed synchronization is ongoing in the inertia phase, the coupling-side clutch torque continues to increase rather than waiting for synchronization to complete. This continuous torque application reduces shift time while maintaining smoothness through controlled torque transfer
Data Source
AI summary
A shift control method can be used for a vehicle with a dual-clutch transmission (DCT). A controller determines whether or not a power-on upshift is initiated in a state in which a high performance mode has been selected. The controller performs a torque phase in which a coupling-side clutch torque is gradually increased and a release-side clutch torque is gradually released. The coupling-side clutch torque is gradually increased to a target coupling-side clutch torque corresponding to a value obtained by adding a push feel torque to a base torque. The controller performs an inertia phase in which the coupling-side clutch torque is gradually increased while tracing an engine torque such that an engine speed is synchronized with a coupling-side clutch speed. The controller completes speed change through gradual decrease of the coupling-side clutch torque.