Cost of ownership-efficient hybrid electric vehicle powertrain sizing for multi-scenario driving cycles

During the last decade, hybrid electric vehicles have gained a presence in the automotive market. On the streets, in motorsports and in society, hybrid electric vehicles are increasingly common. Many manufacturers have become involved in hybrid electric vehicles, while others have hybrid electric vehicle projects in development. Thus, there is already a great variety of hybrid electric vehicles in production, from small microhybrid vehicles to range extenders. Although there are some hybrid electric vehicles designed for urban driving or luxury segments of the market, most of the market share is aimed to the same kind of use and driving, resulting in potentially subsized or oversized hybrid systems that could lead to inefficient use of the vehicle’s fuel-saving capabilities in many situations. The present work studies the influence of the sizes of the powertrain components (i.e. the engine, the motor and the battery) on the fuel economy under different assumptions: city driving, highway driving and mixed driving. The utilized framework permits the calculation of the theoretically optimum powertrain sizes assuming a particular target. Different drivers and different traffic conditions are also evaluated. Finally, a long-term cost evaluation is carried out to estimate the optimal sizes of the hybrid electric vehicle powertrain as functions of the type of use of the vehicle throughout its life cycle.