Impact of straight vegetable oil-diesel blends application on vehicle regulated and non-regulated emissions over legislated and real world driving cycles

Straight vegetable oil (SVO) has been considered as a possible alternative to fossil diesel-engine fuel since the development of diesel engines. In Europe, SVOs achieved a measurable share in biofuels market reaching 4%. This study attempts to identify the impact of untreated SVO application on fuel consumption and emissions, regulated and non-regulated, on a Euro 3 common rail diesel passenger car. Three different vegetable oils (cottonseed, sunflower, and rapeseed) were blended with diesel fuel, on a 10-90% v/v ratio each. Chassis dynamometer measurements were conducted including both regulated and non-regulated pollutants. In the case of rapeseed oil-diesel blend, carbonyl compounds (10 aldehydes and ketones) were investigated. In addition to the legislated procedure (NEDC), the Artemis driving cycles were used for quantifying the fuels’ impact over realistic driving conditions. Results indicate that all blends have limited effects on gaseous pollutants and vehicle performance. Statistically significant increases on CO₂, CO and HC were recorded over NEDC in the order of 3, 39 and 31%. Reductions were observed on PM emissions particularly for the sunflower oil blends, while NOx remained at baseline levels. Comparison with the emission levels measured when using esterified fuels of the same feedstocks suggests that SVO presence does not affect engine exhaust in the same way as biodiesel. The vegetable oil presence in the fuel appeared to suppress the formation of nucleation mode particles. Straight rapeseed oil increased carbonyl compound emissions over all cycles tested and resulted in higher acroleine/acetone presence in the carbonyl compound composition.     

Thermal analysis of a Li‐ion battery module under realistic EV operating conditions

The thermal behavior of a Li‐ion battery module that belongs to the battery system of an actual electric vehicle prototype was numerically investigated. Realistic driving loads and passive cooling conditions were considered. A combination of a vehicle dynamics model, an equivalent electric circuit battery model, and a 3D finite‐element thermal model was used in the analysis. Temperature and electric potential measurements, performed at the cell and module levels, were first used for model calibration. Electric currents, associated with the ARTEMIS driving cycles, were then calculated and applied in the battery model to predict the heat sources for the thermal model. It was found that the temperature increase corresponding to urban transportation requirements in European countries is tolerable. Nevertheless, road and highway applications would result in a temperature increase that accelerates cell ageing, and an active cooling strategy is required. Copyright © 2012 John Wiley & Sons, Ltd.     

Analysis of magnetotail flux rope events by ARTEMIS observations

Three earthward flowing magnetic flux ropes observed in the duskside plasma sheet at geocentric solar magnetospheric coordinate X~–55 Re by P1 and P2 of acceleration,reconnection,turbulence and electrodynamics of moon’s interaction with the sun mission during 13:00–15:00 UT on July 3,2012,were studied.The morphologies of the flux ropes were studied in detail based on Grad-Shfranov reconstruction method and electronic pitch angle distribution data.It is found that(1)the flux rope cross-sectional dimensions are 1.0 Re×0.78 Re,1.3 Re×0.78 Re,and 2.5 Re×1.25 Re,respectively.The magnetic field lines were asymmetric about the center with field line compression on both sides of the current sheet at the leading region;(2)the electron energy flux data presented asymmetry with larger electron flux and lower temperature in the precursor region.The flux ropes were blocked by the resistance of compressed particle density in the front central plasma sheet and the enhanced magnetic field on its sides;and(3)it is found that the flux rope has a layered structure.From inside out,event 1 can be divided into three regions,namely electronic depletion core region,closed field line region,and the caudal area possible with fields connected with the ionosphere.It suggests that the flux ropes cannot merge with the tail magnetic field lines near the lunar orbit.Especially,the flux rope asymmetrical shape reflects the different reconnection processes that caused it on both sides of the magnetic structure.The events shown in this paper support the multiple X-line magnetic reconnection model for flux ropes with in situ observations.