Potential nine-speed gearbox may be joined by hybrid-electric powershift with ZE capability, it says
Allison has revealed details of a hybrid-electric driveline that will allow the diesel engine to be switched off and on again when the vehicle is moving at speed.
The product is of similar dimensions to the T3270R xFE gearbox that is already established in the UK market. While Allison says that it is not yet talking to vehicle manufacturers, it believes that there is potential for the six-speed powershift hybrid unit to become established here.
ZE capable hybrid
“The benefits of this product include the ability to run in zero-emission mode through geofencing with no infrastructure requirements,” says Area Director UK and Republic of Ireland Ashley Brooks.
Mr Brooks sees the latest-generation hybrid’s ability to harvest energy to drive the vehicle in zero-emission mode as being of particular value in double-deck bus applications. There, the vehicle’s weight means that it has a lot of kinetic energy.
Allison has also globally launched its nine-speed automatic gearbox. The unit is targeted for release in 2020 and Mr Brooks says that it will offer a market-leading ratio spread, delivering potential fuel savings.
“The nine-speed gearbox casing is slightly longer than the xFE, so it would require packaging work to fit existing models. There is definitely potential in a coach or bus applications,” he adds. Maximum input torque for the nine-speed unit is 1,200Nm and it is compatible with stop-start technology.
Efficiency all round
The nine-speed ‘box uses early activation of the torque converter lockup clutch that is common with the xFE range. The xFE uses dynamic shift points that are based on a software map of the engine along with optimised gear ratios.
“As a result, we know the power unit’s ‘sweet spots’ for efficiency and keep engine speed within them,” says Mr Brooks. xFE gearboxes have been fully integrated into Optare’s single-deck bus range (pictured).
