83 research outputs found
End-of-Life Impact on the Cradle-to-Grave LCA of Light-Duty Commercial Vehicles in Europe
A cradle-to-grave life cycle assessment focused on end-of-life (EoL) was conducted in this study for three configurations of a light-duty commercial vehicle (LDCV): diesel, compressed natural gas (CNG), and battery electric vehicle (BEV). The aim is to investigate the impact of recycling under two EoL scenarios with different allocation methods. The first is based on the traditional avoided burden method, while the second is based on the circular footprint formula (CFF) developed by the European Commission. For each configuration, a detailed multilevel waste management scheme was developed in compliance with the 2000/53/CE directive and ISO22628 standard. The results showed that the global warming potential (GWP) impact under the CFF method is significantly greater when compared to the avoided burden method because of the A-parameter, which allocates the burdens and benefits between the two connected product systems. Furthermore, in all configurations and scenarios, the benefits due to the avoided production of virgin materials compensate for the recycling burdens within GWP impact. The main drivers of GWP reduction are steel recycling for all of the considered LDCVs, platinum, palladium, and rhodium recycling for the diesel and CNG configurations, and Li-ion battery recycling for the BEV configuration. Finally, the EoL stage significantly reduces the environmental impact of those categories other than GWP
Life cycle assessment of an NMC battery for application to electric light-duty commercial vehicles and comparison with a sodium-nickel-chloride battery
This paper presents the results of an environmental assessment of a Nickel-Manganese-Cobalt (NMC) Lithium-ion traction battery for Battery Electric Light-Duty Commercial Vehicles (BEV-LDCV) used for urban and regional freight haulage. A cradle-to-grave Life Cycle Inventory (LCI) of NMC111 is provided, operation and end-of-life stages are included, and insight is also given into a Life Cycle Assessment of different NMC chemistries. The environmental impacts of the manufacturing stages of the NMC111 battery are then compared with those of a Sodium-Nickel-Chloride (ZEBRA) battery. In the second part of the work, two electric-battery LDCVs (powered with NMC111 and ZEBRA batteries, respectively) and a diesel urban LDCV are analysed, considering a wide set of environmental impact categories. The results show that the NMC111 battery has the highest impacts from production in most of the impact categories. Active cathode material, Aluminium, Copper, and energy use for battery production are the main contributors to the environmental impact. However, when vehicle application is investigated, NMC111-BEV shows lower environmental impacts, in all the impact categories, than ZEBRA-BEV. This is mainly due to the greater efficiency of the NMC111 battery during vehicle operation. Finally, when comparing BEVs to a diesel LDCV, the electric powertrains show advantages over the diesel one as far as global warming, abiotic depletion potential-fossil fuels, photochemical oxidation, and ozone layer depletion are concerned. However, the diesel LDCV performs better in almost all the other investigated impact categories
A real time zero-dimensional diagnostic model for the calculation of in-cylinder temperatures, HRR and nitrogen oxides in diesel engines
A real-time zero-dimensional diagnostic combustion model has been developed and assessed to evaluate
in-cylinder temperatures, HRR (heat release rate) and NOx (nitrogen oxides) in DI (Direct Injection) diesel engines under steady state and transient conditions. The approach requires very little computational time, that is, of the order of a few milliseconds, and is therefore suitable for real-time applications. It could, for example, be implemented in an ECU (Engine Control Unit) for the on-board diagnostics of combustion and emission formation processes, or it could be integrated in acquisition software installed on
an engine test bench for indicated analysis. The model could also be used for post-processing analysis of previously acquired experimental data.
The methodology is based on a three-zone thermodynamic model: the combustion chamber is divided into a fuel zone, an unburned gas zone and a stoichiometric burned gas zone, to which the energy and mass conservation equations are applied. The main novelty of the proposed method is that the equations can be solved in closed form, thus making the approach suitable for real-time applications.
The evaluation of the temperature of burned gases allows the in-cylinder NOx concentration to be calculated, on the basis of prompt and Zeldovich thermal mechanisms. The procedure also takes into account the NOx level in the intake charge, and is therefore suitable for engines equipped with traditional short-route EGR (Exhaust Gas Recirculation) systems, and engines equipped with SCR (Selective Catalytic Reduction) and long-route EGR systems.
The diagnostic model was tested on a GMPT-E Euro 5 diesel engine, under both steady-state and fast transient conditions. The experimental data were acquired at the dynamic test bench of ICEAL-PT (Internal Combustion Engine Advanced Laboratory at the Politecnico di Torino)
A real time zero-dimensional diagnostic model for the calculation of in-cylinder temperatures, HRR and nitrogen oxides in diesel engines
A real-time zero-dimensional diagnostic combustion model has been developed and assessed to evaluate
in-cylinder temperatures, HRR (heat release rate) and NOx (nitrogen oxides) in DI (Direct Injection) diesel engines under steady state and transient conditions. The approach requires very little computational time, that is, of the order of a few milliseconds, and is therefore suitable for real-time applications. It could, for example, be implemented in an ECU (Engine Control Unit) for the on-board diagnostics of combustion and emission formation processes, or it could be integrated in acquisition software installed on
an engine test bench for indicated analysis. The model could also be used for post-processing analysis of previously acquired experimental data.
The methodology is based on a three-zone thermodynamic model: the combustion chamber is divided into a fuel zone, an unburned gas zone and a stoichiometric burned gas zone, to which the energy and mass conservation equations are applied. The main novelty of the proposed method is that the equations can be solved in closed form, thus making the approach suitable for real-time applications.
The evaluation of the temperature of burned gases allows the in-cylinder NOx concentration to be calculated, on the basis of prompt and Zeldovich thermal mechanisms. The procedure also takes into account the NOx level in the intake charge, and is therefore suitable for engines equipped with traditional short-route EGR (Exhaust Gas Recirculation) systems, and engines equipped with SCR (Selective Catalytic Reduction) and long-route EGR systems.
The diagnostic model was tested on a GMPT-E Euro 5 diesel engine, under both steady-state and fast transient conditions. The experimental data were acquired at the dynamic test bench of ICEAL-PT (Internal Combustion Engine Advanced Laboratory at the Politecnico di Torino)
Life cycle assessment of an on-road dynamic charging infrastructure
On road dynamic charging represents a possible solution for the electrification of the transport sector and eventually, for its decarbonisation. However, only a few studies have evaluated the environmental impact of this technology. A detailed life cycle assessment (LCA) of charging infrastructure is missing. This study is a life cycle assessment of the construction and maintenance of an electrified road (e-road) equipped with dynamic wireless power transfer technology (DWPT). The data from an e-road tested in a test site in Susa (Italy) have been adapted for motorway applications. The results show the relevance of wireless power transfer components compared to traditional components and materials. The wireless power transfer (WPT) component production in fact accounts for more than 70% of the impacts in the climate change category, even though it represents less than 1% weight. Maintenance is the phase with the highest impact due to the structural features of the e-road. However, there is considerable uncertainty about this value which still requires further refinement when more data from e-road monitoring are available
Analysis of the Exhaust Gas Recirculation System Performance in Modern Diesel Engines
Exhaust gas recirculation (EGR) is extensively employed in diesel combustion engines to achieve nitrogen oxides emission targets. The EGR is often cooled in order to increase the effectiveness of the strategy, even though this leads to a further undesired impact on particulate matter and hydrocarbons. Experimental tests were carried out on a diesel engine at a dynamometer rig under steady-state speed and load working conditions that were considered relevant for the New European Driving Cycle. Two different shell and tube-type EGR coolers were compared, in terms of the pressure and temperature of the exhaust and intake lines, to evaluate thermal effectiveness and induced pumping losses. All the relevant engine parameters were acquired along EGR trade-off curves, in order to perform a detailed comparison of the two coolers. The effect of intake throttling operation on increasing the EGR ratio was also investigated. A purposely designed aging procedure was run in order to characterize the deterioration of the thermal effectiveness and verify whether clogging of the EGR cooler occurred. The EGR mass flow-rate dependence on the pressure and temperature upstream of the turbine as well as the pressure downstream of the EGR control valve was modeled by means of the expression for convergent nozzles. The restricted flow-area at the valve-seat passage and the discharge coefficient were accurately determined as functions of the valve lift
Optimization of the layout and control strategy for parallel through-the-road hybrid electric vehicles
This paper describes the optimization of the layout and of the control strategy of through-the-road (TTR) parallel hybrid electric vehicles equipped with two compression-ignition engines that feature different values of maximum output power.
First, a tool has been developed to define the optimal layout of each TTR vehicle. This is based on the minimization of the powertrain and fuel cost over a 10-year time span, taking into account the fuel consumption. Several performance requirements are guaranteed during the optimization, namely maximum vehicle velocity, 0-100 km/h acceleration time, gradeability and the all-electric range.
A benchmark optimizer that is based on the dynamic programming theory has been developed to identify the optimal working mode and the gear number, which are the control variables of the problem. A mathematical technique, based on the pre-processing of a configuration matrix, has been developed in order to speed up the calculation time.
After the layout optimization, the potential of the two identified hybrid vehicles in improving the fuel economy, compared with the conventional vehicle, has been analyzed and discussed over several driving missions, i.e., the New European Driving Cycle, the Artemis Urban Driving Cycle, the Artemis Rural Driving Cycle, the Artemis Motorway Driving Cycle and the Federal Test Procedure. The contributions related to the vehicle electrification and to the control strategy were identified separately.
Finally, a real-time optimizer has also been developed, which is based on the instantaneous maximization of an equivalent powertrain efficiency
Impact of Different LCI Modelling Scenarios on the LCA Results, A Case Study for the Automotive Sector
Since vehicles are comprised of thousands of components,
it is essential to reduce the Life Cycle Inventory
(LCI) modelling workload. This study aims to compare
different LCI modeling workload-reducing scenarios to
provide a trade-off between the workload efforts and result
accuracy. To achieve the optimal balance between computational
effort and data specification requirements, the driver
seat is used as a case study, instead of the entire vehicle. When
all the components of a conventional light-duty commercial
vehicle are sorted by mass descending order, seats are among
the first five. In addition, unlike the other components, seats
are comprised of metals as well as a wide range of plastics and
textiles, making them a representative test case for a general
problem formulation. In this way, methodology and outcomes
can be reasonably extended to the entire vehicle. Regarding
the methodology, this study investigates the use of the
International Material Data System (IMDS), thus primary
data are used. First, the Life Cycle Assessment (LCA) of the
reference scenario is evaluated, in which the LCI model is
developed using the full list of substances at element level. The
reference scenario is characterized both by the highest degree
of details and major workload efforts. Second, the authors
consider three workload-reducing scenarios, which they refer
to as: the cut-off, the Verband Der Automobilindustrie (VDA)
and the one-substance-one-material scenarios. Then, granularity
is added, and different levels of disaggregation are
considered for all scenarios. Results indicate that when the
reference scenario is compared to the cut-off scenarios, environmental
impacts are significantly different in certain impact
categories (e.g., Abiotic Depletion) even with the smallest
cut-off (1%). In contrast, when Global Warming Potential
(GWP) is considered, the difference is negligible for any value
of cut-off ranging from 1 to 5%. As a result, if the focus is
solely on the GWP, the cut-off is a viable workload-reducing
strategy. Finally, the VDA and the One-substance-onematerial
scenarios appear to be the best compromises in terms
of workload and accuracy. The One-substance-one-material
scenario achieves the highest accuracy compared to the other
workload-reducing scenarios
Assessment of a low-throughput predictive model for indicated cycle, combustion noise and NOx calculation in diesel engines in steady-state and transient operations
Transient flow and Cavitation Simulation in an Automotive Diesel Injection System using a Novel Second-Order Accurate Implicit Finite-Difference Scheme
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