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The legislation limits for pollutants emissions are strongly pushing OEMs to electrification of their vehicle fleet. Even high performance car manufacturers are taking on the challenge of using electrification - a trend also observed for premium and exotic vehicles. This electrification job is seen from some manufacturers as an opportunity to increase the vehicle performances while moving to more “green” powertrains. It means that the installation of electric power on the vehicle should certainly not affect the performances of the vehicle models with only an internal combustion engine, but increase the performances while cutting the pollutants emissions during driving. As such it is no easy task, since the hybrid system (battery, inverter, and electric motor) affects strongly the overall vehicle weight and thus its driving dynamics as well as system cost. On top of this most manufacturers look for synergies between hybrid and standard versions in order to minimize cost and investments of the overall vehicle platform. All the arguments above weigh even stronger focussing on high performance cars due to the challenges posed by low to medium production volumes. Because of this, modularity of the specific subsystems plays a key role during the concept selection.

This paper deals with the simulation of the low frequency drivability of through-the-road parallel (TTRP) hybrid electric vehicles (HEVs). The current literature relating to HEVs is predominantly focused on energy efficiency optimisation. However, the drivability of this HEV typology can be particularly critical, due to the interaction of the front and rear axle dynamics. The article presents an experimentally validated non-linear model of a TTRP HEV, consisting of a front axle driven by an internal combustion engine (ICE) with a six-speed transmission, and a rear axle powered by an electric motor with a prototype two-speed transmission. The simulated TTRP HEV is then considered with both driven axles, and drivability manoeuvres in conditions of constant gear are carried out. The results are analysed to study acceleration and jerk profiles, and understand the anti-jerk control system fundamentals through linearisation methods.

Fully electric vehicles and range-extended electric vehicles can be characterised by a multitude of possible powertrain layouts, many of them currently under investigation and comparison. This contribution presents a novel clutchless seamless four-speed transmission system which can be concurrently driven by two electric motor drives, for use in fully electric vehicles or electric axles for through-the-road parallel hybrid electric vehicles. The transmission system allows the electric motors to work in their high efficiency region for a longer period during a typical driving schedule. This paper describes the layout of the novel transmission system, the equations for modelling its dynamics and the criteria for the selection of the best gearshift maps for energy efficiency. Finally, an energy consumption and performance comparison between the novel drivetrain, a conventional single-speed electric drivetrain and a double-speed electric drivetrain is discussed in detail for two case study vehicles.