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In order to reduce the pollutant emissions (NOx and PM) of diesel engines, the addition of small gaseous fuel amounts or dual mode operation have been proved as potential techniques. This paper is focused on a detailed characterization of the particles emitted from a single cylinder diesel engine when part of the diesel fuel (5 to 20% by energy) is replaced by a gaseous fuel (producer gas, mainly composed by H2, CO, CH4 and inert compounds) coming from biomass steam gasification. The engine was run at constant speed and torque and different EGR rates. Particle samples were collected by means of fiber glass filters placed in a dilution mini-tunnel. Simultaneously, during tests, part of the exhaust gas was conducted to an SMPS to determine the particle size distribution.

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 objective of this work was the development of an on-road in-vehicle emissions measurement technique utilizing a relatively new, commercial, portable Fourier Transform Infra-Red (FTIR) Spectrometer capable of identifying and measuring (at approximately 3 second intervals) up to 51 different compounds. The FTIR was installed in a medium class EURO1 spark ignition passenger vehicle in order to measure on-road emissions. The vehicle was also instrumented to allow the logging of engine speed, road speed, global position, throttle position, air-fuel ratio, air flow and fuel flow in addition to engine, exhaust and catalyst temperatures. This instrumentation allowed the calculation of mass-based emissions from the volume-based concentrations measured by the FTIR. To validate the FTIR data, the instrument was used to measure emissions from an engine subjected to a real-world drive cycle using an AC dynamometer.

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.

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.