Improving the Energy Efficiency and Operating Performance of Heavy Vehicles by Powertrain Electrification

Aalto University, P.O. Box 11000, FI-00076 Aalto www.aalto.fi Author Antti Lajunen Name of the doctoral dissertation Improving the Energy Efficiency and Operating Performance of Heavy Vehicles by Powertrain Electrification Publisher School of Engineering Unit Department of Engineering Design and Production Series Aalto University publication series DOCTORAL DISSERTATIONS 125/2014 Field of research Vehicle Engineering Manuscript submitted 6 June 2014 Date of the defence 10 September 2014 Permission to publish granted (date) 18 August 2014 Language English Monograph Article dissertation (summary + original articles) Abstract In this thesis, the potential of hybrid and electric powertrains to improve the energy efficiency and operating performance of heavy vehicles and heavy machinery have been evaluated with scientific research methods. The evaluation was carried out by using representative case applications among on-road heavy vehicles and heavy machinery. These applications are a city bus, an underground mining loader and a heavy vehicle combination. The key objective of this thesis was to analyze the impact of powertrain electrification on the energy efficiency and operating performance. For city buses and underground mining loader, cost effectiveness was also analyzed. The role of the different electrical energy storages in powertrain electrification was evaluated throughout the different phases of this research for each vehicle application. Many aspects need to be taken into consideration when introducing electric powertrains for heavy vehicles and machinery. Important aspects are the operating environment, strategy and schedule. In this context, this thesis introduces several methods to evaluate these different aspects in terms of energy efficiency and operating performance. These methods are based on vehicle simulation, which was the main research method. Vehicle simulation is a very powerful tool to develop and evaluate different vehicle powertrain technologies. During the research, different vehicle simulation software were used the main tool being the MATLAB/Simulink. The various simulation results clearly showed that the energy efficiency of the heavy vehicles can be significantly improved by powertrain electrification. It is being underlined that the improvement depends on the powertrain topology, operating cycle, and also energy storage system configuration. According to the cost calculations results, the hybrid and electric city buses have, in most situations, higher life cycle costs than the diesel buses whereas a hybrid underground loader has already potential to be economically more profitable than a diesel loader. The various performance analyses of the energy storages in different heavy vehicle applications showed that the current lithium-ion battery technology provides good performance in terms of power and energy capacity. However, the battery costs and durability are still importance challenges in order to improve the cost effectiveness of heavy vehicles.In this thesis, the potential of hybrid and electric powertrains to improve the energy efficiency and operating performance of heavy vehicles and heavy machinery have been evaluated with scientific research methods. The evaluation was carried out by using representative case applications among on-road heavy vehicles and heavy machinery. These applications are a city bus, an underground mining loader and a heavy vehicle combination. The key objective of this thesis was to analyze the impact of powertrain electrification on the energy efficiency and operating performance. For city buses and underground mining loader, cost effectiveness was also analyzed. The role of the different electrical energy storages in powertrain electrification was evaluated throughout the different phases of this research for each vehicle application. Many aspects need to be taken into consideration when introducing electric powertrains for heavy vehicles and machinery. Important aspects are the operating environment, strategy and schedule. In this context, this thesis introduces several methods to evaluate these different aspects in terms of energy efficiency and operating performance. These methods are based on vehicle simulation, which was the main research method. Vehicle simulation is a very powerful tool to develop and evaluate different vehicle powertrain technologies. During the research, different vehicle simulation software were used the main tool being the MATLAB/Simulink. The various simulation results clearly showed that the energy efficiency of the heavy vehicles can be significantly improved by powertrain electrification. It is being underlined that the improvement depends on the powertrain topology, operating cycle, and also energy storage system configuration. According to the cost calculations results, the hybrid and electric city buses have, in most situations, higher life cycle costs than the diesel buses whereas a hybrid underground loader has already potential to be economically more profitable than a diesel loader. The various performance analyses of the energy storages in different heavy vehicle applications showed that the current lithium-ion battery technology provides good performance in terms of power and energy capacity. However, the battery costs and durability are still importance challenges in order to improve the cost effectiveness of heavy vehicles.