Allison expands range of buys transmissions

The latest models offer enhanced torque capacity, durability, shift quality and levels of fuel economy. To meet customer demand for more power and torque, the transmissions feature 'shift energy management' (SEM), to better manage the torque. Rich Price, director of Asia Pacific engineering at Allison explains that, by modulating the engine torque before the shift is engaged, clutch energy and temperatures are lowered, so increasing durability and offering higher ratings capacity. In the new models, which have been designed for city bus applications, that counts for a lot: SEM provides a 200Nm increase in input torque ratings, compared to the T375 and T375R models. "Power and torque levels continue to rise, yet bus OEMs want to retain the size and weight advantages our transmissions offer," says Price. And he also makes the point that SEM means Allison can provide OEMs with a transmission that satisfies design and operational requirements needed today, while preparing for growth in other markets. "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)," adds Price. 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. "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," claims Price.