In this study, the concept of selecting the propulsion system parameters of an extended-range electric vehicle (EREV) powered from a supercapacitor (SC) pack and a range extender (REX) consisting of Internal Combustion Engine (ICE) and Electric Generator (G) was presented. The methodology of parameter selection was verified by computer simulation as well as by laboratory tests. On the basis of initial laboratory tests, parameters (capacitance as a function of the terminal voltage) of the supercapacitors pack were determined and subsequently used in the EREV simulation model. The tests were carried out for the Worldwide harmonized Light vehicles Test Cycle (WLTC), and the vehicle parameters were scaled to the capabilities of the laboratory stand. Research on EREV powered from supercapacitor pack allowed to conclude that it is possible to properly select the capacitance of SC pack and the power of the REX, so that the WLTC cycle can be realized. Thanks to EREV powered from SC it is possible to work at the point of the highest efficiency of ICE, which is associated with the least fuel consumption.

A range extender is an auxiliary power unit, usually consisting of an internal combustion engine and an electric generator, which is used to charge a battery of an electric vehicle in order to increase its range. This paper considers a range extender supplied with liquefied petroleum gas (LPG). The aim is to provide detailed data on thermal efficiency, brake specific fuel consumption (BSFC), and unit emission of carbon dioxide (CO₂) in a broad spectrum of range extender operating conditions defined by rotational speed and torque. The experimental investigation has been conducted using a laboratory test stand equipped with an energy dissipation system of adjustable resistance. Measurement results, including fuel flow rate, were processed using custom algorithm for generating maps, i.e., two-dimensional dependencies of the considered parameters on the rotational speed and torque. The maps obtained for LPG supply were compared with those for gasoline supply. The results demonstrated feasibility of LPG-supplied range extender. Its BSFC and thermal efficiency were at a comparable level to those obtained for gasoline supply, but with less CO₂ emission. The empirical data collected has been adopted in the simulation of extended-range electric vehicle in a driving cycle, showing the potential of utilizing the results of this study.

Introduction. An Extended-Range Electric Vehicle (EREV) is a type of electric vehicle that uses an additional internal combustion engine (ICE) to charge the battery in order to provide the vehicle with a greater range than in electric only mode. Purpose. Analysis and comparison of the performance of EREV powertrain managed according to three control strategies: pure electric mode, hybrid mode with ICE constantly working, and hybrid mode with ICE working only at high power demand. Methods. The tests were carried out using a laboratory test stand that represented the structure of EREV powertrain. Liquefied petroleum gas was used as a fuel to supply the ICE. The test conditions were defined by a special driving cycle simulating urban driving. Results. Time series plots of selected parameters of electric motor, electrochemical battery pack, range extender generator and active load system. Practical value. Among the considered control strategies of EREV powertrain, the energy balance of the electrochemical battery is negative for a purely electric mode, significantly positive for continuous range extenders (REXs) operation mode and moderately positive for the mode with REX activation only in dynamic states.