Feedback Control of Synchronizers for Reducing Impacts during Sleeve to Gear Engagement
Paper in proceedings, 2020

This paper presents a feedback control strategy aimed to reduce noise and wear during gearshifts in conventional and hybrid Dual Clutch Transmissions (DCT and DCTH) and Automated Manual Transmissions (AMT). The control strategy is based on a new dog teeth position sensor developed by China Euro Vehicle Technology AB and existing speed sensors in the transmission. During gear shifting, noise is generated by impacts between the sleeve teeth and the idler gear dog teeth after speed synchronization. Besides noise, these impacts are also responsible for delaying the completion of shift and contribute to wear in the dog teeth, hence reducing the lifespan of the transmission. The presented control strategy controls speed synchronization such that the impact between sleeve and idler gear dog teeth, before the start of torque ramp up, is avoided. Since drag torque is an important factor in speed synchronization, this paper also contains an algorithm to identify friction torque coefficient in the transmission. The identification method ensures that the controller adapts to varying conditions without the need for offline calibration. The control strategy is developed for standard automatic gear shifting operations but minor adaptations in the algorithm also make it capable of handling gear shifts requested by the driver. The output signal of the control strategy is acceleration request on idler gear during speed synchronization. To make controller easier to implement and minimize shift time, the acceleration request only has two values, either maximum value or zero. The control strategy is designed in such a way that it can easily be integrated in the existing transmission control software. By applying the control strategy on a detailed simulation model, it is shown that the impacts during gear engagement are significantly reduced.

Author

Muddassar Piracha

Chalmers, Electrical Engineering, Systems and control, Automatic Control

Anders Grauers

Chalmers, Electrical Engineering, Systems and control, Automatic Control

Johan Hellsing

China-Euro Vehicle Technology (CEVT) AB

SAE Technical Papers

0148-7191 (ISSN)

Vol. 2020-April April

SAE 2020 World Congress Experience, WCX 2020
Detroit, USA,

Areas of Advance

Transport

Subject Categories

Vehicle Engineering

Control Engineering

Other Electrical Engineering, Electronic Engineering, Information Engineering

DOI

10.4271/2020-01-0960

More information

Latest update

1/5/2021 1