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Regulated gaseous emissions and particle concentrations, with commercial diesel fuel, animal fat biodiesel and gas to liquid (GTL) fuel from a Low Temperature Fischer-Tropsch process, have been studied. Tests were carried out in a light duty vehicle (Nissan Qashqai, 110 kW, Euro 4) equipped with variable geometry turbocharger (VGT), cooled exhaust gas recirculation (EGR), common rail with split fuel injection strategy, diesel oxidation catalyst (DOC) and diesel particle filter (DPF). Vehicle tests were carried out at real-world driving conditions. Specific emissions, in g/km, were determined separately for two test circuits (urban and extraurban). Results show that the use of alternative fuels reduced THC and CO emissions compared to diesel fuel while only slight differences were observed in NOx emissions and in particle number concentration.

The work has been focused on the measurement and analysis of the main Diesel emissions from an automotive Diesel engine mounted in a test bench prepared for operating in different transient sequences. The engine was fuelled with a conventional fuel and an emulsified fuel. A commercial pure low sulphur diesel fuel and an emulsified fuel (water in oil, w/o) with 5% v/v of water, were used as test fuels. A smoke meter and a gaseous emissions analyser allowed for the study of the effect of these fuels on the Diesel emissions under the different operating transient sequences. The properties of the test fuels and the time-recording of some engine parameters, such as fuel/air ratio or exhaust gas recirculation ratio, were used for the analysis and interpretation of the results.

The effect of the biodiesel feedstock on the engine performance and emissions is expected to become increasingly important as the emissions regulations become more stringent (Euro 5). This work aims to study the effect of the degree of unsaturation of a biodiesel fuel (which is a characteristic of the original oil), this being quantified by the iodine number, on the pollutant emissions and combustion timing. Four biodiesel fuels with iodine numbers ranging from 90 to 125 were tested pure and blended (30% and 70% biodiesel content, volume basis) with a diesel reference fuel, which was tested too, in a four-cylinder, 2.2 litre, turbocharged, direct injection diesel engine. The operation modes were selected to be representative of the New European Driving Cycle. In general, pure biodiesel fuels, compared to the reference fuel, resulted in sharp reductions in particle mass and opacity (60-70%) and in a slight increase in both fuel consumption (around 15% in mass) and NOx emissions (9%).

The work has been focused on the measurement and analysis of the smoke opacity and NOx emissions from an automotive Diesel engine fuelled with conventional fuel and a bioethanol-diesel blend. A commercial pure diesel fuel and a blend with 10% v/v of anhydrous ethanol (99.94 %) were used as test fuels. The engine was mounted in a test bench prepared for operating in different transient sequences. A smoke meter and gaseous emissions analyser allowed for the study of the effect of these fuels on the smoke opacity and NOx emissions under different operating transient sequences. The properties of the test fuels and time-recording of some engine parameters, such as fuel/air ratio or exhaust gas recirculation ratio, were used for the analysis and interpretation of the results. The obtained results suggested that the use of the e-diesel blend is an interesting alternative for a significant reduction in smoke opacity.

Methyl esters obtained from the most interesting Spanish oleaginous crops for energy use -sunflower and cynara cardunculus- were both used as diesel fuels in this work, pure and in 25% blends with a reference commercial fuel which was also used pure. A stationary engine test bed, together with the appropriate instrumentation for chemical and morphological analysis, allowed to evaluate the effect of these fuels on the engine emissions, particularly in the main particulate matter characteristics, such as soluble organic fraction, origin of adsorbed hydrocarbons, sulphate content, particle number per unit filter surface, and mean particle diameter. Both the consideration of the main thermochemical properties of the tested fuels and the computations of a chemical equilibrium model were helpful for the analysis of the experimental results.

This paper shows the morphological analysis results of particulate matter emissions from an indirect injection Diesel engine working in two operating modes using Digital Image Analysis Algorithms (DIAA) and a Scanning Mobility Particle Sizer (SMPS). Two typical engine operating modes were selected among the collection of steady stages, which reproduce the sequence of operating conditions that the vehicles equipped with this type of engines must follow during the transient cycle established in the European Emission Directive 70/220. The DIAA results were obtained from images of particulate matter collected in filters. The filters were charged in a dilution mini-tunnel, connected up-stream and down-stream of a cyclone-based particulate filtration system, which was coupled to the engine exhaust line. The images were obtained by a Scanning Electron Microscope (SEM) from samples taken directly from the charged filters.

A nonequilibrium approach for the instantaneous calculation of the composition of 29 chemical species is used in this work to simulate the evolution of the gas composition in a Diesel engine cylinder from the start of combustion to the exhaust opening. A discretization of the heat release law is used as a sequential source of combustion products, which are then subjected the evolution of pressure directly measured from the cylinder engine, and to the evolution of a burnt-zone temperature obtained from the same pressure signal through a diagnosis thermodynamic model. For each burning fuel package, the equilibrium composition and the corresponding adiabatic flame temperature are considered as initial conditions for the kinetic calculation of the gas composition evolution.

The particulate reduction targets imposed by regulations require wide knowledge about the effect of fuel formulation on both particulate emissions and composition. The results of a set of engine steady test-bed experiments, extraction procedures and chemical analysis are presented in this paper, aiming to study the effect of some of the main fuel properties on the particulate emissions and composition of a typical European passenger car Diesel engine. The tested fuels had different properties (density, volatility, cetane number, aromatic content, sulphur content, etc.), and also different engine operating conditions such as torque and engine speed, were tested.

With the objective of optimising the measurement procedure, the influence of different operating parameters of a certification-like dilution mini-tunnel, such as the dilution ratio and the filtering temperature, is firstly presented in this paper. By means of an environmental chamber, both blank and charged filters were subjected to a range of different temperature and humidity conditions, as well as to different conditioning time periods. In all cases the weighted filters from the mentioned tests were subjected to a soxhlet extraction method, which permitted the chemical analysis of both the soluble organic fraction by gas chromatography and mass spectrometry, and the insoluble one by high performance liquid chromatography (HPLC) and infrared spectrography. Also the contribution of fuel and lubricant to the particulate matter was determined. All this information was related to the mini-tunnel operating parameters and to the ambient conditions.

The results from the experimental diagnosis of the combustion process taking place in a 0.5 litre single cylinder D.I. Diesel engine with common rail injection system are presented and analysed in this paper. Some parameters characterising the injection process were modified during the experimental study, such as the start of injection, the pressure in the common rail and the injection hole diameter. Fuel delivery was kept constant in all cases. The tests were scheduled with two objectives: to determine the separate effect of each of the mentioned parameters, and to analyse the effect of the spray characteristics, for which injection pressure and hole diameter values were combined to provide similar injection rate and injection duration. The combustion diagnosis was carried out using a thermodynamic model based on the instantaneous thermodynamic properties of the gas in the chamber, which are affected in the model by the injection law input.