Abstract
Keywords
Dual Clutches
Dual Clutch Transmission (DCT)
Wet Clutches
Dry Clutches
Powershift Transmission
Abstract
The next generation vehicles are under severe pressure from governments / environmentalists and consumers to reduce emissions and increase fuel economy, while maintaining the same performance and reliability. This has prompted FGP to investigate alternatives to automatic transmissions (AT) for some applications. One of the options considered is the Dual Clutch Transmission. However, there are two possible alternatives to the launch clutch for this type of gearbox, either a wet clutch or dry clutch system.
This paper describes the methodology utilized in analyzing the most appropriate clutch system considering the overall fuel economy, performance and reliability. In addition, the study encompasses the impact of the clutch system to the gearbox design, packaging and risk. Comfort and functionality, typical on most automatic transmissions were assessed using simulations and vehicle tests. Different modes of operation that are critical to the functionality and / or failure modes are verified with vehicle tests. Results show that both clutch systems have unique advantages and disadvantages. However, both systems can achieve the driving comfort of an AT in normal driving maneuvers. Wet system offers more consistent and dynamic response even with higher torque applications. The fuel economy (MVEG) advantage of the dry system of 2-3% versus the wet has been assessed for both gas and diesel engine applications based on simulations and actual vehicle tests.