Dual-Clutch Gear Shift Torque Shaping for Driver Perception
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Solution Overview
Problem
The average driver's perception of a dual-clutch gearbox shift as progressive rather than instantaneous leads to a feeling of deceleration or acceleration holes, which is contrary to the expected torque changes in traditional single-clutch gearboxes, affecting driving pleasure.
Innovation Solution
A control method for dual-clutch gearboxes that incorporates an additional torque profile from an electric machine to simulate impulsive torque changes during gear shifts, mimicking single-clutch sensations by temporarily modifying the torque objective.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual-clutch gearbox performs progressive torque transfer during gear shift, then transmission continuity is improved, but driver perception of performance deteriorates
Solution Approach 1:
The control unit applies a compensatory torque profile from the electric machine before and during the gear shift to counteract the perceived performance loss. This preliminary anti-action creates an artificial torque boost that compensates for the progressive clutch transfer, making the shift feel more like a traditional single-clutch gearbox to the driver.
Solution Approach 2:
The system dynamically changes the torque output parameter of the electric machine during the gear shift event. By modulating the electric machine's torque contribution in real-time based on clutch state, the system transforms the smooth dual-clutch transfer into a perceived impulsive transition that matches driver expectations.
2Productivity
If dual-clutch gearbox maintains constant torque during shift, then performance is improved, but driving pleasure deteriorates
Solution Approach 1:
The control system applies a periodic torque modulation pattern during the gear shift, creating an impulsive torque profile with distinct phases (torque reduction followed by torque boost). This periodic action replicates the characteristic sensation of traditional gear shifts, providing driving pleasure while maintaining overall performance through the electric machine's compensation.
Data Source
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AI summary
Control method to carry out a gear shift in a manual automatic transmission (6) provided with a gearbox (7) having at least one clutch (13) and in a road vehicle (1) having an internal combustion engine (4) and at least one reversible electric machine (11). The control method involves the steps of: receiving a gear shift command; opening and closing the clutch (13) to allow the drive gear to be changed from the current gear (A) to the following gear (B); determining a torque objective (TM) to be generated by the electric machine (11); controlling the electric machine (11) to pursue the torque objective (TM); and adding, only and exclusively during the gear shift, to the torque objective (TM) an additional torque profile (Tadd) which is impulsive and temporary and temporarily modifies the development of the torque objective (TM).