Abstract With the introduction of new regulations on emissions, fuel efficiency, driving cycles, etc. challenges for the powertrains are significantly increasing. In order to fulfil these regulations, hybrid- electric powertrains are an unquestioned option for short and long-term solutions. Hybridization however, is not only fulfilling these challenging efficiency or emission targets, but also allows numerous new possibilities on control strategies of different powertrain elements as well as new approaches of designing them. A good example is transmissions where, hybridization allows a new transmission type called Dedicated Hybrid Transmission (DHT), which enables to use novel control strategies bringing improved performance, driveability, durability and NVH behavior. This paper focuses on the novel shift strategy where friction clutches do not have to slip. The strategy introduces a novel shifting control using the integrated electric motor and special power flow of the dedicated hybrid transmissions. The novel shift strategy significantly improves shift comfort, thermal losses and element durability. In addition, several design aspects are challenged by proposing questions like selection of dog clutches over friction clutches, usage of eCVT modes in DHT and how a DHT shall be designed,. Introduction Hybrid-electric vehicles are one of the solutions to improve fuel efficiency and pollutant emissions of automobiles [ 1]. The combinatory control of combustion engine and electric motor (propulsion elements) during vehicle operation comprises additional control tasks compared to conventional vehicles [ 2]. An emerging transmission type, called DHT, enables gear shifting without dissipation losses during shifting, depending on the topology and dimensioning: The topology has to allow so-called eCVT-gears, which are characterized by an additional mechanical degree of freedom compared to fixed ratio gears. Fixed ratio gears are defined by a fixed gear ratio from every transmission propulsing shaft to the transmission output shaft [ 3]. In contrary, eCVT-gears are defined by enabling variable speed ratios from transmission propulsion shaft to the output shaft. A specific topology may allow from several up to all shifting events without dissipation. Besides the topology of the transmission, actuator limitations (especially propulsion elements) have to be considered to judge the limitation on the dissipationless gearshifts. As an example, actuator limitations may extend the duration of the dissipationless gearshift. In required cases, actuator limit violations are compensated by conventional shifting events (shifts with slipping elements). Figure 1. A VL Future Hybrid 7-mode transmission. For details on design and characteristics, see [ 4] and [5] Therefore, dimensioning of (mainly) the propulsion elements is essential for the operating range of dissipationless shifts and shifting durations for such shifts that are possible within their operating area. The primary target of drivetrain control is to provide driver demand torque to the driven wheels. Due to the availability of two propulsion elements, DHT topologies allow to control a second target: In fixed ratio gears, analog to parallel hybrid-electric vehicles, the battery state of charge (SOC) is controlled. In eCVT gears the driver demand Novel Shift Control without Clutch Slip in Hybrid Transmissions2017-01-1110 Published 03/28/2017 Muammer Yolga and Markus Bachinger A VL LIST GmbH CITATION: Yolga, M. and Bachinger, M., "Novel Shift Control without Clutch Slip in Hybrid Transmissions," SAE Technical Paper 2017-01-1110, 2017, doi:10.4271/2017-01-1110. Copyright © 2017 SAE InternationalDownloaded from SAE International by University of British Columbia, Wednesday, August 01, 2018can be followed, but SOC control is only possible indirectly via controlling a target speed of one propulsion element (e.g. for perfect sweet spot tracking of the combustion