According to latest European Union (EU) findings, CO2 emissions from heavy duty vehicles, including lorries, buses and coaches, account for about 6 % of the total CO2 emissions in the Union and to about 25 % of the total CO2 emissions from road transport. It is expected that without further measures, the share of CO2 emissions from heavy duty vehicles will increase by around 9 % between 2010 and 2030. The constant growth in demand for on-road transport underlines the urgency of cleaner and more fuel-efficient global on-road transport vehicles fleets. In February 2019, the EU finally decided to set CO2 limits for on-road commercial vehicles for the first time. Legislation requires a 15 % CO2 reduction scenario in 2025 and a 30 % CO2 reduction scenario in 2030 based on the 2019 baseline fleet. Most heavy-duty vehicles (HDVs) are nowadays powered by diesel engines. Diesel powertrain hybridization has demonstrated its ability to significantly reduce the fuel consumption and thus the CO2 emissions in various medium duty and heavy duty applications. This paper presents a comprehensive simulation study to evaluate the fuel savings potential of a serial-parallel hybrid heavy duty truck. The innovative configuration consists of a transmission with a reduced number of gears and parts designed to achieve a good compromise between system losses and weight. The two electric machines integrated into the dedicated hybrid transmission system enable three different driving modes, namely electric driving with one or two electric machines, serial driving and a parallel mode. The fuel economy results as well as the tailpipe pollutant emissions are compared with a conventional powertrain and a parallel hybrid (P2) configuration in different operating profiles. A future emissions legislation scenario is therefore introduced. Optimal sizing of the electrical components of the hybrid configurations (battery and electric machines) will be considered. Also, the total purely electric driving range of the electrified powertrains will be compared to current industrial benchmarks.

Mr. Theodoros Kossioris, VKA / RWTH, GERMANY Dr.-Ing. Joschka Schaub, FEV Europe GmbH, GERMANY Dr.-Ing. Markus Ehrly, FEV Europe GmbH, GERMANY Mr. Johannes Maiterth, FEV Europe GmbH, GERMANY Mr. Ruben Keizer, FEV Europe GmbH, GERMANY Mr. Dieter van der Put, FEV Europe GmbH, GERMANY