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Series BEV with a Small Battery Pack and High-Efficiency ICE Onboard Electricity Production: B-Class, High-Roof Hatchback and Le Mans Hypercar Applications
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on September 15, 2020 by SAE International in United States
Battery electric vehicles (BEV) suffer from the high economic and environmental costs to produce and dispose of the batteries, and the low specific energy density, per unit mass and unit volume, of their batteries. Coupled to the still limited contribution by renewable energy to the needs of total primary energy supply (TPES), the lack of a widespread recharging infrastructure for electric vehicles, and the latest advances of both compression ignition and positive ignition internal combustion engines (ICEs), that have reached the 50% fuel conversion efficiency mark, well above the average fuel conversion efficiency of combustion fuels power plants, it is thus suggested to couple small battery packs to high efficiency on board electricity generation by ICEs. Based on simple empirical design rules derived from existing production battery electric vehicles, with and without a range extender, ICE, a simple model based on the solution of the Newton’s equation of motion for a vehicle, and more complex simulations by a computer aided engineering (CAE) modelling of BEVs, the advantages of the proposed solution are highlighted in both range and energy economy. By considering the BEV platform of a BMW i3, a small 30 A·h battery pack may permit a range of 40 miles without the onboard ICE electricity generator, and a range of 39 miles with the ICE onboard electricity generator. The EPA Miles-per-gallon-of gasoline-equivalent (MPGe) combined city/hwy are then 130 and 127 miles respectively. This MPGe working electric is 12% better than the BEVs with a larger battery pack and no range extender, or 27% better than the BEVx with a larger battery pack and a traditional range extender. In the case of the high efficiency ICE on-board electricity generator, the EPA Miles-per-gallon (MPG) is 62 miles. The range is 60 miles with onboard gasoline storage of 0.96 gallons. Small increments of the fuel tank capacity translate in large improvements of the range with minimal reduction of the energy economy. This MPG is 13% better than any present plug-in-hybrid-electric-vehicle (PHEV) currently available. The proposed BEV with high efficiency ICE on-board electricity production has a MPGe exceeding 12% the MPGe of the 42.2 kWh battery capacity BEV without range extender, and of 27% the MPGe of the 42.2 kWh battery capacity BEV with range extender. The proposed BEV with high efficiency ICE on-board electricity production has an MPG exceeding by 13% the MPG of the best PHEV, reaching at the most 54 MPG. A long range, lighter, smaller battery pack, BEV, fitted with the proposed high efficiency, on-board, ICE generator based on the latest available ICE technologies, both positive or compression ignition, is thus superior, for both the economy and the environment, to short range. larger battery pack, heavier, BEVs that are only recharged by a limited recharging infrastructure feed with a substantial non-renewable energy input.