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The current legislation does not take into account the limitation of sub 23 nm particles from engine. Nevertheless, the Common Rail Diesel engine emits a large number of nanoparticle, solid and volatiles, that are very dangerous for human health. In this contest, the challenge of the “dieper EU project” is to apply advanced technologies for exhaust after-treatment to existing diesel engines and to optimize the characteristics of a new generation of engines with regards to emissions, fuel consumption and drivability. Aim of the present paper is to provide useful information for the development of the after-treatment system that will have to fulfill Euro6 further steps. In order to characterize the chemical and physical nature of Particulate Matter emitted from Euro 6b Medium Duty diesel engine, the pollutants were collected and analyzed: from engine-out, downstream of the particulate filter (DPF), and at the exit of a selective catalytic reactor (SCR).

In this paper the characteristics of a mixture of glycerol-based ethers usable in a compression ignition engine are investigated, in terms of efficiency and emissions. Alternative pathways for the energetic exploitation of biodiesel derived glycerol became of increasing interest as the biodiesel production was increased worldwide. Because of its detrimental physical and chemical properties, raw glycerol is hardly usable in conventional internal combustion engines (ICE). However, etherification of glycerol with tert-butyl alcohol and isobutylene allows obtaining a mixture mainly composed of higher glycerol ethers (GEM) suitable for compression ignition engines. Thus, the aim of this research study was to test a mixture of mono-, di- and tri-tert-butyl ethers of glycerol in blend with a commercial diesel fuel in a compression ignition engine, evaluating the fuel efficiency and the impact on the pollutant emissions.

The purpose of this paper is to present a 3-D Finite Element Method able to simulate and predict exhaust transmission noise. The simulation takes into account fluid flow pulsation, aeroacoustic noise sources, flow-induced structural vibration as well as noise radiation in the far field of the exhaust system of a single-cylinder diesel engine. In order to study problems on fluid-structure interaction a 3-dimensional model has been created through a FEM simulation. The study includes the calculation of the transmission loss factor and the determination of which modes dominate the noise transmission. Simultaneously, an experimental measurement has been performed, in order to determine the transmission loss factor of the tested system. Finally, an experimental-numerical comparison has been performed. Experimental and numerical results have been compared and a good agreement has been found.

An extensive experimental work has been made in order to analyze the structure of the spray of a large-angle single-hole high-pressure swirl injector for direct-injection spark-ignited (DISI) gasoline engines. Spatial and temporal evolution measurements of the spray have been carried out in an optically accessible vessel. The spray has been lighted by an 80 mm thickness and 12 ns duration pulsed laser sheet, generated by a 532 nm Nd-YAG laser, both along the spray axis and in cross sections perpendicularly to it. The scattered light has been collected at 90° from the laser sheet direction by a digital CCD camera with a frame grabber synchronized to the single-shot injection command and the laser start pulse. A digital image processing system has allowed analyzing the images collected by the CCD camera. It has been possible to visualize the formation and the spatial and temporal evolution of the initial liquid slug (pre-spray) and of the hollow-cone and solid-cone stray structure.

Natural gas is a viable alternative fuel to obtain low exhaust emissions. A heavy duty DI Diesel engine was converted to Otto cycle natural gas operation. Two alternative solutions were compared: lean-burn technology; stoichiometric feed with three-way catalyst and EGR. Power and efficiency were similar for the two above solutions, and exhaust temperature resulted similar to the diesel engine in both cases due to the diluted operation. The lean bum engine met EURO II ECE-R49 limits except for total hydrocarbons. Stoichiometric engine emissions resulted much lower than the limits. Particulate emissions were quite negligible for the two solutions.

The capabilities of the Taylor analogy breakup (TAB) and wave breakup (WB) spray models, already existing in the literature, were evaluated in KIVA-II code. Also, a novel droplet deformation and breakup (DDB) model that takes into account the nonlinear effects which manifest at large deformation of the drops was incorporated and tested in KIVA-II. The assessment of the three models was performed by using experimental measurements of tip penetration, spray cone angle and Sauter mean radius (SMR) in a cylindrical optically accessible closed vessel at room temperature and high gas density. High speed photography and laser light extinction techniques were simultaneously used to detect data along a n-heptane jet coming out from a single hole nozzle of 0.20 mm diameter supplied by PE-Bosch injection pump operating in single shot by electro-hydraulical device. The KIVA calculations with TAB model in terms of penetration and SMR do not predict accurately the experiments.