High-performance transmission specialist Oerlikon Graziano, brand of Oerlikon Drive Systems Segment, presented its range of hybrid transmission systems at the 2017 CTI Symposium and Transmission Expo USA, in Novi, Michigan. The focus was on the hybrid transmission concept, which promises a step forward on the path to electrification, with a compact and elegant package and full hybrid capabilities.

Oerlikon Graziano presented a paper entitled “Modular P2-P3 Dedicated Hybrid Transmission for 48V and HV Applications.” The company has designed and patented an elegant DHT concept, starting from the know-how cumulated in the last years from the concept of the OGeco transmission. This has been achieved by continuous improvement activities ongoing on the demo vehicle and focusing on the market needs. The transmission is a modular concept which starts from a traditional 2-shaft single-clutch transmission. Thanks to a link between two main gears of the gearbox and the direct gearing between the electric machine and this linked gear arrangement, free-mounted on the primary shaft, the concept allows to have a very efficient electric path of the transmission, which presents two different gear ratios between the electric machine and the secondary shaft.

The solution is particularly innovative, because keeping a very simple and well known architecture (so cost effective), it allows the connections to be made with standard transmission components, selectively coupling the electric machine to either the primary or the secondary shaft. This feature, then, represents a mixed P2-P3 hybrid architecture and therefore takes the advantages of both (e.g. powershifting-P3, recuperation-P3, cranking-P2, standstill charging-P2). It allows a performance increase of up to 40 percent on 0-100 kph and up to 25 percent benefit on CO2 emission with the installed electric power being 30 percent of the total. Thanks to its scalability and to the possibility of having different power-split configurations the system can be used both as a mild-hybrid or as a plug-in hybrid solution, within a 48V or HV system.

Between the products on display the new entry in the electric range products is EMR3, a single speed transmission for battery electric vehicle, designed for a maximum input torque of 270 Nm and max input speed of 14,000 rpm. The lubrication concept is developed to guarantee maximum flexibility in term of installation angle to allow the highest level of compatibility with different vehicle layout. Another remarkable factor is represented by the compact design (150 mm center distance input shaft), for weight optimization.

The 4SED Twin-Drive 4-Speed Electric Drive is a power-shifting gearbox with low-cost design that includes two small motors and four ratios to provide a wider range of operation at higher efficiency.