Voith has stayed on track with the development of its new DIWA NXT transmission for buses. Test bench and test track results have proven the predicted efficiency and reduction in emissions. The new transmission features a mild-hybrid system with an optional 48V central recuperation unit (CRU) and offers an optimal gear ratio through an additional overdrive gear for inter-city applications. A model of the new transmission will be on display at the IAA Commercial Vehicles 2018 trade show in Hanover, Germany, this September.
Following the initial announcement at IAA 2016, Voith continued to work on the new DIWA NXT transmission. The DIWA NXT provides significant performance optimization through the separation of torque converter and retarder circuits which provides both improved traction and braking performance. It also offers an optimal gear ratio through a second overdrive gear resulting in a wider transmission ratio spread for higher flexibility in driveline design, making the DIWA NXT also applicable for inter-city buses and coaches.
The new transmission from Voith will have an optional mild-hybrid system. The CRU is based on 48 V technology with a continuous power of 25 kW (peak power: 35 kW). It recuperates energy in downhill and deceleration phases and makes it available to the vehicle’s electrical system via the battery and a DC/DC converter as well as for traction. As a result of the unique design of the DIWA transmission, the CRU can be integrated into the flywheel side of the transmission that normally houses a transmission torque converter. This integrated design strategy requires almost no additional installation space. In addition, the transmission is user-friendly to maintain and service. Start of production for Voith’s DIWA NXT is expected early 2021.
