Exergo-technological explicit methodology for gas-turbine system optimization of series hybrid electric vehicles

Abstract

Significant research efforts have been invested in the automotive industry on hybrid electrified powertrains in order to reduce the dependence of passenger cars on oil. Electrification of powertrains resulted in a wide range of hybrid vehicle architectures. The fuel consumption of these powertrains strongly relies on the energy converter performance, as well as on the energy management strategy deployed on board. This paper investigates the potential of fuel consumption savings of a series hybrid electric vehicle using a gas turbine as an energy converter instead of the conventional internalcombustion engine. An exergo-technological explicit analysis is conducted to identify the best configuration of the gasturbine system. An intercooled regenerative reheat cycle is prioritized, offering higher efficiency and higher power density than those of other investigated gas-turbine systems. A series hybrid electric vehicle model is developed and powertrain components are sized by considering the vehicle performance criteria. Energy consumption simulations are performed over the Worldwide Harmonized Light Vehicles Test Procedure driving cycle using dynamic programming as the global optimal energy management strategy. A sensitivity analysis is also carried out in order to evaluate the impact of the battery size on the fuel consumption, for self-sustaining and plug-in series hybrid electric vehicle configurations. The results show an improvement in the fuel consumption of 22-25% with the gas turbine as the auxiliary power unit in comparison with that of the internal-combustion engine. Consequently, the studied auxiliary power unit for the gas turbine presents a potential for implementation on series hybrid electric vehicles.

Technological analysis and fuel consumption saving potential of different gas turbine thermodynamic configurations for series hybrid electric vehicles

“…The identified realistic GT-system options of Bou Nader et al 5 (Figure 3) are assessed here in order to account for their energy efficiency and net specific work. The assessment methodology for each option is illustrated in Figure 2.…”

“…As for the compression work, it was demonstrated that the use of an intercooler to reject heat during the compression phase is technically feasible and induces an increase in the efficiency and net specific work of the system. 5,16–18…”

“…This thermodynamic machine has been largely investigated by different automotive companies over the years as a main EC that can substitute the internal combustion engines (ICEs) in conventional powertrains. 1–5 Automotive manufacturers were attracted by many GT intrinsic benefits, such as the reduced number of components and rotating parts compared with ICE, the reduced vibration as well as the multi-fuel capability. 1…”

A Stirling Engine for Automotive Applications

“…The powertrain modelling, sizing and equations are presented in [10]. The electric traction motor is sized in order to ensure similar performance to a medium class hybrid vehicle, with maximum speed of 160 km/h and acceleration from 0-100 km/h in 9.6 s. Consequently, an 80kW tractive power electric machine is selected.…”

“…As for the capacity, three different values of 5, 10 and 20 kWh are considered in the analysis in order to assess the impact of the battery size on improving fuel consumption. The additional battery mass is taken into account and values were retrieved from [10].…”