Antti Lajunen

Evaluation of Energy Storage System Requirements for Hybrid Mining Loaders

The objective of this paper is to evaluate technical requirements for electrochemical energy storage systems (ESSs) in hybrid mining loaders. These requirements take into account power and energy capacity, costs, life cycle, and safety-related requirements. The evaluation of the requirements is based on the characteristics of the current energy storage technology and vehicle simulation results. The evaluation shows that lithium-based batteries offer sufficient power and energy capacity; meanwhile, the requirements for cost and cycle life durability are dependent on the operating strategy and configuration of the loader. In particular, the power-intensive duty cycle of a mining loader can be challenging for batteries in terms of cycle life and thermal management.

Evaluation of the benefits of using dual-source energy storage in hybrid electric vehicles

Batteries are often used as energy storage in hybrid and electric vehicles. Despite of the development, technical characteristics of batteries are the most limiting factor for further increasing the energy conversion efficiency and pure electric operation of these vehicles. In this research, dual-source energy storage system, a battery pack and ultracapacitors, has been studied by simulation of hybrid city bus models. These two different types of energy storages have complementary characteristics therefore their combination provides both high energy and high power to weight ratio. Based on the simulation results, the benefits of using dual-source energy storage in hybrid city bus are evaluated demonstrating the advantages of the proposed energy storage system.

Investigation of thermal energy losses in the powertrain of an electric city bus

This paper evaluates thermal losses and thermal energy transfer in the powertrain components of an electric city bus. A simulation model of an electric city bus was developed in AMESim simulation software. Simulations were carried out in four different driving cycles and in different ambient temperatures. The simulation results show that there is a strong correlation between thermal losses of the inverter and electric motor with the total energy losses. Based on the results, thermal energy transfer from the components to the coolant was analyzed. The thermal energy transfer from the battery to coolant was higher in more demanding driving cycles whereas aggressive driving has more impact on the thermal energy transfer of the inverter and electric motor. In cold ambient temperature, auxiliary power losses increase significantly due to the need of heating. Battery losses are also higher in cold conditions because of the higher internal resistance.

Comparison of Different Powertrain Configurations for Electric City Bus

This paper presents a comparison between different powertrain configurations in electric city buses. The comparison is carried out with the aid of modeling and simulation in the Autonomie vehicle simulation software. The aim of the presented research is to evaluate the advantages and disadvantages of the different powertrain configurations in terms of energy efficiency, powertrain losses and component design requirements. In this case, a powertrain configuration includes at least a battery system, inverter, traction motor, and also some configurations can include a gearbox, reduction gear or differential gear. General design requirements for the powertrain components were defined on the basis of the performance requirements in a typical city bus operation. The simulation results show that the powertrain configuration has notable impact on the energy consumption, and the distribution of losses in the powertrain.

Comparison of different buffering topologies in FC-hybrid non-road mobile machineries

This paper presents powertrain comparison for fuel cell hybrid non-road mobile machinery. The objective of this study is to investigate the feasibility of different fuel cell hybrid powertrain topologies. This study concentrates on hybrid powertrain topologies which are generated from the fuel cell source output to loading inverters inputs. The compared features of different powertrains are efficiency, weight, size, cost and lifetime costs, as well as, benefits and disadvantages. The study considers fuel cell hybrid topologies with different active and passive connections of a battery pack, an ultracapacitor pack or the both. The comparison of different powertrain topologies requires a validated simulation tool, specific power control algorithms for each topology, knowledge of the target application and several iteration rounds for simulations.

Evaluation of Diesel and Fuel Cell Plug-In Hybrid City Buses

This research evaluates the energy efficiency and cost effectiveness of diesel and fuel cell plug-in hybrid city buses. Corresponding vehicle models were developed in the Autonomie simulation software and simulations were carried out with predefined operation schedules. According to the schedules, the battery is being charged at the end stations of the operation route, and the target operation time in electric driving mode is 70% from the duration of the route. Based on the simulation results, the energy efficiency and operating performance were evaluated in relation to a battery electric bus. The results show that the battery electric bus has the lowest energy consumption whereas the diesel plug-in hybrid bus has the lowest lifecycle costs. Cost reductions of the expensive fuel cell technology are necessary in order to make fuel cell plug-in hybrid buses economically competitive.

Measurement Theory and Dimensional Analysis: Methodological Impact on the Comparison and Evaluation Process

Comparison and ranking of solutions are central tasks of the design process. Designers have to deal with decisions simultaneously involving multiple criteria. Those criteria are often inconsistent in the sense that they are expressed according to different types of metrics. This means that usual engineering performance indicators are expressed according to physical quantities (i.e. SI system) and indicators such as preference functions can be “measured” by using other type of qualitative metrics. This aspect limits the scientific consistency of design because a coherent scientific framework will at first require the creation of a unified list of fundamental properties. A combined analysis of the measurement theory, the General Design Theory (GDT) and the dimensional analysis theory give an interesting insight in order to create guidelines for establishing a coherent measurement system. This article establishes a list of fundamental requirements. We expect that these guidelines can help engineers and designers to be more aware of the drawbacks linked with the use of wrong comparison procedures and limitations associated with the use of weak measurement scales. This article makes an analysis of the fundamental aspects available in major scientific publications related to comparison, provides a synthesis of these basic concepts and unifies those concepts together from a designing perspective. A practical design methodology using the fundamental results of this article as prerequisites has been implemented by the authors.Copyright