Browse Publications Technical Papers 2011-01-2194

Clutchless Shifting of an Automated Manual Transmission in a Hybrid Powertrain 2011-01-2194

The normal approach to shifting a manual transmission in a vehicle includes a clutch which connects the engine to the transmission. When shifting, the relative speed of the engine and wheels changes. The transmission is disconnected from the engine with the clutch and the gears in the transmission are pressed together until they engage. There are small friction synchronizers inside the transmission, but these are only designed for the inertia of the gears and the clutch pressure plate. The clutch is required to synchronize the transmission speed with the engine speed after a shift, and to remove the load from the transmission before a shift. Described is a method for automating a manual transmission hybrid-electric powertrain which doesn't require a clutch. A hybrid drivetrain including an electric motor and a combustion engine has the benefit of much better speed and torque control than a combustion engine alone. Drivetrain speed can be controlled to take the load off the transmission, allowing it to be shifted into neutral. Once the transmission is in neutral, the electric motor can synchronize the engine side to the correct speed quickly and accurately, allowing the transmission to shift into the next gear. This provides rapid, efficient shifting without a clutch.


Subscribers can view annotate, and download all of SAE's content. Learn More »


Members save up to 16% off list price.
Login to see discount.
Special Offer: Download multiple Technical Papers each year? TechSelect is a cost-effective subscription option to select and download 12-100 full-text Technical Papers per year. Find more information here.
We also recommend:

Instantaneously Optimized Controller for a Multimode Hybrid Electric Vehicle


View Details


Hybrid Transmission Development for AWD Luxury Cars


View Details


Development of a parallel hybrid electric vehicle


View Details