Automatic Transmissions For City Buses And Coaches
Allison Transmission has added the T390 and T390R models to the Torqmatic range of fully automatic transmissions for bus applications. 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 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 with the T375 and T375R models. Allison's T390 and T390R models are ideally suited to city buses and coaches with engine ratings up to 380HP and 1650Nm. 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),' said Rich Price, director of Asia Pacific Engineering. 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 for 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.
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. Allison's T390 and T390R models are ideally suited to city buses and coaches with engine ratings up to 380HP and 1650Nm. 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),' said Rich Price, director of Asia Pacific Engineering. 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 for 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.
Comments