Search Results

In the recent past, an always increasing attention have been addressed to the definition and optimization of the HVAC system for fully electric vehicles. The new vehicle layouts and the different operating temperatures of the whole powertrain ask for a re-thinking of the HVAC concept for the modern architectures. In this ballpark, the possibility to deal with a compact and efficient apparatus without moving parts and capable to provide both cold and hot fluxes is really attractive. This is the reason why this work deals with the design and optimization of a vortex tube for automotive applications. Such a component, in fact, is capable to separate a highly swirled flow in two different branches, a cold one and a hot one (one inlet - two outlets). The balance in between the two obtained mass flows can be simply realized via ruling the backpressure at the hot side, with keeping constant the cold one.

This paper describes and compares different powertrain configurations for the retrofit of a heavy-duty Class 8 truck, powered by a 12.6 liters diesel engine. The engine is firstly equipped with an electrification-oriented organic Rankine cycle (ORC) system and then coupled to a traction electric machine into a hybrid powertrain. An electrification-oriented ORC system can produce enough energy to cover the ancillary loads, which in long-haul applications for freight transportation are quite demanding. Nevertheless, only powertrain hybridization can achieve significant improvements in the overall system efficiency. Both systems may thus be implemented in the same vehicle, but an efficiency improvement is guaranteed only if the system is carefully managed so as to reach a trade-off between the requirements and potential benefits of the ORC system and those of the hybrid powertrain.

The growing need for a sustainable worldwide mobility is leading towards a paradigm shift in the automotive industry. The increasingly restrictive regulations on vehicle emissions are indeed driving all of the world-leading road vehicles manufacturers to redesign the concept of transportation by developing new propulsion solutions. To this aim, a gradual electrification strategy is being adopted, and several hybrid electric solutions, such as extended-range electric vehicles with reciprocating engines or fuel cells, already represent a valid alternative to conventional vehicles powered by fossil fuels. Despite their appealing features, these hybrid propulsion systems present some drawbacks, mainly related to their complex architecture, causing high overall dimensions, weight and costs, which pose some limitation in their use for small-size vehicles.

The effects of the internal geometry of catalytic converter channels on flow characteristics; exhaust backpressure and overall conversion efficiency have been investigated by means of both numerical simulations and experimental investigations. The numerical work has been carried out by means of a micro scale numerical tool specifically tailored for flow characteristics within converter channels. The results are discussed with aid of flow distribution patterns within the single cell and backpressure figures along the catalyst channel. The results of the numerical investigation provide information about the most efficient channel shapes. An experimental validation of the simulated results has been carried out with a production 3.6 liter, 6-cylinder engine on a dynamic test bench. Both modal and bag emission data have been measured during the FTP-Cycle.

In the last three decades, with the growing concern on environmental impact and with the market demand for safety and lower fuel consumption, aerodynamic development has become a standard part of the automobile design area and it is easy to foresee that this is going to happen very fast also for motorcycles. Furthermore, a new concept of motorcycle called maxiscooter has successfully entered the European market. Maxiscooters represent an evolution of the small size engine scooters (from 50 to 125 cc) that were created in the 50s for city use. This category of motorcycles is aimed to a wealthy and more adult market, which needs a pleasant design, riding comfort and stability at higher speed. On the other hand, such vehicles for city use are passing a critical moment in terms of development of the engines, because of the stricter limits imposed by the environmental regulations and for the consequent and significant effects on performance.

The aerodynamic evaluation that influences the shape of new vehicles is only one of the many different aspects that must be carefully considered in a vehicle design program. However, the aerodynamic development enters from the earliest stages, in the shape optimization program, and continues up to full production level, until the detail is optimized. As wind tunnel measurements continue to be the most common and extensively used approach, the rapid evolution of computers in terms of electronic data processing and storage and the progress achieved in computational fluid dynamics (CFD), suggest its utilization in supporting and reducing experimental tests.

In European Union (EU), transport causes about a quarter of the total greenhouse gases (GHG) emissions and road vehicles are the biggest contributors, with nearly three-quarters of the overall GHG emissions. In this context, many governments are adopting different strategies to achieve a sustainable mobility, including the electrification of public transport, such as full electric taxis (e-taxis). Indeed, battery electric vehicles (BEVs) represent a promising solution towards the achievement of sustainability since they involve zero emissions during the use phase, despite indirect emissions are generated during the charging of the traction battery according to the specific national electricity mix. However, a proper choice of the vehicle segment for the e-taxi and its battery capacity can represent a crucial factor in reducing the overall environmental impacts.

Scale-resolving turbulence modeling for engine flow simulation has constantly increased its popularity in the last decade. In contrast to classical RANS modeling, LES-like approaches are able to resolve a larger number of unsteady flow features. In principle, this capability allows to accurately predict some of the key parameters involved in the development and optimization of modern engines such as cycle-to-cycle variations in a DI engine. However, since multiple simulated engine cycles are required to extract reliable flow statistics, the spatial and temporal resolution requirements of pure LES still represent a severe limit for its wider application on realistic engine geometries. In this context, Hybrid URANS-LES methodologies can therefore become a potentially attractive option. In fact, their task is to preserve the turbulence scale-resolving in the flow core regions but at a significantly lower computational cost compared to standard LES.

Lithium ion batteries are the most promising candidates for electric and hybrid electric vehicles, owe to their ability to store higher electrical energy. As a matter of fact, in automotive applications, these batteries undergo frequent and fast charge and discharge processes, which are associated to internal heat generation, which in turns causes temperature increase. Thermal management is therefore crucial to keep temperature in an appropriate level for safe operation and battery wear prevention. In a recent work authors have already demonstrated the capabilities of a coupled lattice Boltzmann-Finite Volume Method to deal with thermal transient of a three-dimensional air-cooled Li-ion battery at different discharging rates and Reynolds numbers. Here, in order to improve discharge thermal capabilities and reduce temperature levels of the battery itself, a layer of porous medium is placed in contact with the battery so to replace a continuum solid aluminum layer.

The Life Cycle Sustainability Assessment (LCA) methodology is today considered as a crucial paradigm with multiple levels of analysis, including the economic, social and environmental aspects. In this scenario, the purpose of the present research is to carry out an accurate and extensive LCA based analysis to compare the environmental impact, between conventional gasoline and hybrid vehicle powertrains. Two different powertrain scenarios were considered maintaining the same vehicle chassis. The performed analysis concerned resources and energy consumption as well as pollutant emission of each process, evaluating the impact of powertrain production, the vehicle use phase, and powertrain end of life scenarios. A large set of indicators - including human toxicity, eutrophication, and acidification - was considered. The study indicates that the potential of electrified vehicles basically depends on efficient production and recycling of the battery.

Batteries are the key elements for the massive electrification of the transport sector. With the rapidly growing popularity of electric vehicles, it is becoming increasingly important to characterize the behavior of battery packs through fast and accurate numerical models, in order to support experimental activities. A coupled electro-thermal simulation framework is required, as it is the only way to realistically represent the interactions between real world battery pack performances and the vehicle-level thermal management strategies. The purpose of this work is to pave the way for a comprehensive methodology for the development of a supporting modeling framework, to efficiently complement experiments in the optimal design and integration of battery packs.

Vehicle electrification is one of the most important emerging trends in the transportation sector and a necessary step towards the reduction of polluting substances and greenhouse gas (GHG) emissions. However, electric vehicles still present some environmental criticalities, such as indirect emissions related to the electricity used for charging the traction battery, which depends on the considered national electricity generation mix. The leading approach for quantifying the potential environmental impacts is the Life Cycle Assessment (LCA), a standardized methodology that takes into account the whole life cycle of a product, including production, use phase, and end-of-life.

The second-life use of batteries from electric vehicles (EV) represents an excellent and cost-effective option for energy storage applications, including the control of fluctuations in energy supply and demand or in combination with solar photovoltaic and wind turbine. Indeed, these batteries are normally replaced from EV use before the end of their service life, when they still have 70-80% of the original capacity. Depending on the cell chemistry and the specific design, such batteries can still be employed in less stressful applications than the automotive one, including commercial, residential, and industrial applications. With the aim to promote the transition to a circular closed-loop economy for spent traction batteries, this study consists in a systematic literature review of available options for reusing EV batteries as a storage system in a factory environment, highlighting benefits and critical aspects.

Due to their ability to store higher electrical energy, lithium ion batteries are the most promising candidates for electric and hybrid electric vehicles, whose market share is growing fast. Heat generation during charge and discharge processes, frequently undergone by these batteries, causes temperature increase and thermal management is indispensable to keep temperature in an appropriate level. In this paper, a coupled Lattice Boltzmann-Finite Volume model for the three-dimensional transient thermal analysis of an air-cooled Li-ion battery module is presented. As it has already been successfully used to deal with several fluid-dynamics problems, the Lattice Boltzmann method is selected for its simpler boundary condition implementation and complete parallel computing, which make this approach promising for such applications.

The port-logistic industry has a significant impact on the urban environment nearby ports and on the surrounding coastal areas. This is due to the use of large auxiliary power systems on ships operating during port stays, as well as to the employment of a number of fossil fuel powered road vehicles required for port operations. The environmental impact related to the use of these vehicles is twofold: on one hand, they contribute directly to port emissions by fuel consumption; on the other hand, they require some of the ship auxiliary systems to operate intensively, such as the ventilation system, which must operate to remove the pollutants produced by the vehicle engines inside the ship. The pathway to achieve decarbonization and mitigation of energy use in ports involves therefore the adoption of alternative and cleaner technology solutions for the propulsion systems of such port vehicles.