Allison introduces new T390 + T390R bus transmissions

Allison Transmission announces addition of two new bus transmissions featuring "shift energy management" to provide higher ratings, superior durability and economy

June 4, 2010

Allison Transmission used the recent bus and coach expo Busworld in Shanghai to announce the addition of two new bus transmissions featuring "shift energy management" to provide higher ratings, superior durability and economy.

The company added the new T390 and T390R models to its proven Torqmatic series of fully automatic bus transmissions

These latest models use high levels of powertrain integration to enhance torque capacity, durability, shift quality and economy.

To support the trend for higher engine power and torque, Allison has implemented "shift energy management" (SEM) to dynamically manage torque through the transmission.

This seamlessly modulates the engine torque before the shift is engaged, lowering clutch energy and temperatures, increasing durability and offering higher ratings capability.

In the case of the new T390 and T390R city bus transmissions, SEM provides a 200Nm increase in input torque ratings compared with the T375 and T375R models they supercede.

"Power and torque levels continue to rise, yet bus OEMs want to retain the size and weight advantages our transmissions offer," says Rich Price, Director of Asia Pacific Engineering.

"SEM means Allison can provide OEMs with a transmission that satisfies design and operational requirements needed today."

Allison’s new T390 and T390R models are suited to city buses and coaches with engine ratings up to 380 horsepower and 1,650Nm.

Additionally, the new T390R transmission includes an output retarder feature for enhanced vehicle braking.

Introduction of SEM ensures the most effective utilisation of Allison’s fuel economy software features.

"SEM makes the most of load based shift scheduling (LBSS) and enables new features such as super economy shift scheduling (SESS) and vehicle acceleration control (VAC)," Price adds.

SESS, developed by Allison, monitors operating conditions and automatically up-shifts to a higher gear as soon as tractive effort requirements are met. This feature allows the bus to remain in the highest gear as long as possible, even during slower speed operation to maximise fuel economy.

VAC is focused on driver input and controls acceleration to maintain a smooth, fuel efficient acceleration rate for specific controlled duty cycles or fuel efficiency benefits.

"Together with proven technologies such as auto neutral and reduced engine load at stop (RELS) available across our Torqmatic series of bus transmissions, Allison offers a comprehensive range of tools for optimising bus fleet fuel efficiency," concludes Price.

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