NEW ALLISON T390 AND T390R BUS TRANSMISSIONS FEATURE SHIFT ENERGY MANAGEMENT
Direct control of engine torque through Shift Energy Management enables increased torque rating for buses with no increase in weight or size providing. Allison Transmission announced the addition of new T390 and T390R models to the proven Torqmatic Series of fully automatic transmissions for bus applications during the 2010 Shanghai Busworld exhibition. These latest models use a high level of powertrain integration to enhance torque capacity, durability, shift quality and economy. To support a continuing trend for ever increasing engine power and torque, Allison is implementing Shift Energy Management (SEM) to dynamically manage torque through the transmission.
By seamlessly modulating the engine torque before the shift is engaged, clutch energy and thus temperatures are lowered, 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 to the T375 and T375R models.
Allison’s new T390 and T390R models are ideally suited to city buses and coaches with engine ratings up to 380 HP and 1650Nm. Additionally, the new T390R transmission includes an output retarder feature for enhanced vehicle braking. Introduction of SEM ensures the most effective utilization of Allison’s fuel economy software features, because 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), according to Allison representatives. SESS, developed by Allison, monitors operating conditions and automatically upshifts 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 maximize 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.
