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The main goal of the work presented here was to compile a review of the available literature on the effects of diesel fuel properties on emissions from heavy-duty diesel engines (HDDEs). Because of the large number of various studies that have been performed in this area, the present review is mainly based on the most comprehensive recent research programs: the European Programme on Emissions, Fuels and Engine Technologies (EPEFE), and the USA Programs EPA Heavy-Duty Engine Working Group (EPA-HDEWG) and Diesel Emission Control – Sulfur Effect (DECSE). Fuel properties that have been identified over the years as influencing emissions from HDDEs, and were considered in this work, are cetane number, density, aromatics (total and poly-), sulfur and oxygen contents and back-end distillation. The impact of fuel sulfur content on emission control systems was reviewed, based mainly on the findings of the latest DECSE Program, which was concluded in 2000.

As passenger car exhaust emissions are becoming less pollutant, the share of Heavy Duty vehicle (HDV) emissions to the overall air pollution (local and regional) is increasing, especially for NOx and particles. However, adequate methodologies to model the emissions of a HDV in real world conditions do not yet exist. The main problems for generating accurate emission factors for HDV are 1) Since measurements on HDV engine test beds and/or HDV chassis dynamometers are rather expensive most national projects are based on small data bases. This makes it difficult to model fleet average emission bahvior. 2) Most emission models are based on steady-state measurements. Consequently, they are not properly equipped to make accurate predictions of emissions for the transient driving conditions that occur on the road. The influence of these transient conditions is for most of the driving cycles not negligible.

The paper concerns field measurements for validation of the simulation method VEMOSIM developed in Finland. The field measurements and their analyses were carried out in the following order: - Quantification of; - drive resistance coefficients by coasting; and - power train losses by acceleration; - Utilization of parameters quantified in computer simulation of fuel consumption; - Based on the drive resistance coefficients and power train losses one can use VEMOSIM and produce the fuel consumption amounts of vehicle drives on the test road sections, and finally; - Comparison of the results received from simulation with the ones received from field measurements. The test vehicle was a truck trailer combination with 7 axles and the mass was 61,060 kg. The simulated results (speed and fuel consumption) are in a very good agreement with the measured ones taking into account the inaccuracy of the input data of the road vertical alignment.

Emissions of Heavy Duty vehicles (HDV) are becoming more and more important as emission levels of passenger cars drop significantly. In contrast to passenger cars, where cold start extra emissions are investigated extensively, only few data is available for fuel consumption and emissions after cold starts for HDV. On the chassis dynamometer emissions in real world urban driving cycles for HDV have been measured at operating temperature and after a cold start. The measurements show significant increases of energy consumption and emissions. For example fuel consumption is about 18% and particle mass emissions are about 30% to 50% higher at cold start.

The greenhouse gas emission reduction targets agreed at Kyoto represent a first step to reduce emissions in the long term in order to stabilize the earth's climate. The European Union has made an important contribution to the Kyoto agreement and the European Commission intends to develop a strategy to reach the Union's Kyoto target. This will require action in all sectors of the economy including the transport sector. Of the six gases covered by the Kyoto protocol, carbon dioxide (CO2) is the most important as it accounts for about 80% of the total global warming potential of all six greenhouse gases. In the European Union, the share of transport CO2 emissions in total increased from 19% in 1985 to 26% in 1995. Road traffic is the most important source, and largely determines the trend in the transport sector; and road freight accounts for about 35% of transport CO2 emissions. As well as CO2, road freight transport causes considerable amounts of other pollutant emissions.

Measurements of ultrafine particles (diameter < 300 nm) and total suspended particulates (TSP) were performed in 2 tunnels (Lundby, Gothenborg, S, and Plabutsch, Graz, A). The measurements in the Lundby tunnel were performed directly in the tunnel tube at the roadside whereas the measurements at the Plabutsch tunnel took place at the top of a 90 m high ventilation shaft. There was good correlation for all diameters (7.91 nm - 300 nm) between ultrafine particles and TSP for the measurements at the Lundby tunnel. At the Plabutsch site a correlation between ultrafine particles and TSP was detected only for particles > 35 nm. The maximum of the particle size distribution function for Lundby was at 30 nm and for the Plabutsch tunnel at 80 nm.

Motivated by the possibility of future emission regulations based on particle number as well as mass, after-treatment of ultrafine particles by a cordierite wallflow filter has been investigated. In a laboratory simulation, synthetic carbon particles of known size and concentration in air were captured with number-based efficiency exceeding 70% in the 20–100 nm size range. Effects of temperature, up to 400°C, filter loading time and ambient-temperature sample dilution have been quantified. Steady-speed and European drive cycle results for the same filter fitted to a passenger car with gasoline direct-injection engine have shown promising reductions in emissions, except at the highest speed of the cycle.

In this study, the performances of two filter media, (Cellulose single layer and dual layered wool non wool/cellulose with electrically charged fibre) for automotive cabin air cleaning application, are investigated. Pressure drops of “clean” and dust loaded filter, fractional efficiencies and behaviour of dust loading were measured. The measurements were carried out in a panel filter housing like that specified by the Society of Automotive Engineers SAE J726 Air Cleaner Test Code. Dual-layered filter, as expected, has filtration efficiency and pressure drops very higher than single layer filter. The flow fields inside the test housing were, also, measured using a Pitot tube. The filter in the housing is exposed to non uniform velocity with very high velocities in the center and lower velocities toward the edge. These velocity variations may be expected to affect the performance of the filter, in terms of efficiency, pressure drops and dust holding capacity.

A prototype multiwavelength sensor able to characterise soot emissions in Diesel exhaust in terms of size and concentration has been tested against other methods for diesel particle measurements like electrical mobility sizing (SMPS) and raw exhaust gravimetric sampling (RES). Measurements carried out with the prototype sensor were correlated with the SMPS by assuming spherical and/or fractal aggregate morphology of the particles. Correlation of RES gravimetric data against the sensor and the SMPS led to the calculation of the solid density for soot particles to be 2.3 gr/cm3.

The last decade of the twentieth century can be considered the starting decade of scaling engineering. Previously unimaginable devices such as: electrostatic, magnetic, pneumatic and thermal actuators, motors, valves, gears and tweezers at nano, meso and micro scales have been reported. The paper presents some experimental results regarding the particular aspects of fluid flow through microdevices that could be applied to automotive engineering. Based on these aspects, there are analyzed the models used in the literature and conclude on some possible assumptions for computational purpose.

Traditional ways for evaluating emission factors, especially for new engines or vehicles, are based for engines on the measurement of engine emission maps or of some points of the map, and for passenger cars on the procedure described in the emission standards. The measurement conditions of these methods are quite far from the actual conditions of the emissions on the road. The actual conditions of the emissions on the road are described and compared to the standards. The different sources of error in building emissions factors are listed. The influence of the different parameters on emissions are shown, in order to assess the necessity of using actual use emissions rather than standard emissions. The different methods of emission factor measurement are presented, together with the main parameters of the emission models, and the present research carried out in Europe to increase the accuracy of the emission factor assessment for road vehicles.

Automotive Industry is pursuing a huge R&D effort aimed at developing an alternative to the traditional Internal Combustion Engine by exploiting the Fuel Cell technology. In the simplest form, the Fuel Cell engine uses Hydrogen as fuel. An electrochemical cell combines hydrogen and oxygen from the air to produce Electricity and Heat, emitting only water vapor. The electric power is than used to supply an electric power-train.

Three-dimensional steady compressible turbulent flow fields in two types of inlet manifold are numerically simulated using the arbitrary Lagrangian - Eulerian (ALE) method. The effects of turbulence are represented by k-ɛ turbulence model. Intake and outflow boundaries are pressure inflow and outflow. All calculations are performed under the same inflow/outflow boundary condition. Mass flow rates of all manifold exits are calculated and compared to evaluate the manifold designs. The results indicate that the structure types of a multi-cylinder diesel engine inlet manifold have great effects on the engine discharge efficiency and CFD is a powerful tool in intake manifold design.

Till recently, the application of the detailed combustion chemistry approach as a predictive tool for engine modeling has been a sort of a “taboo” motivated by different reasons, but mainly, by an exaggerated rigor to the chemistry/turbulence interaction modeling. The situation has drastically changed only recently, when STAR-CD and Reaction Design declared in Deur et al. (2001) the aim to combine three-dimensional flow solver with detailed chemistry analysis based on the Chemkin and Surface Chemkin packages. Relying on their future developments, we present here the methodology termed the “generalized partially stirred reactor”, PaSR, model incorporated into the KIVA code.

In the present paper the KIVA3V code is used to model the behaviour of different combustion chambers, to be used in Common Rail engines with a single displacement lower than 0.5l. Some design parameters have been chosen to evaluate their influence on the combustion patterns. The optimum levels of turbulence and air mean motion have been selected with reference to some specific points of the engine map, managed by mean of multiple injection. Therefore the different combustion chambers geometries have been numerically investigated in terms of fluidynamic behaviour as well as in terms of combustion evolution. After that some chamber geometries, especially suitable for the second-generation common rail engines, have been selected.

A novel stochastic model of droplets breakup is proposed and implemented into computation of liquid sprays. The evolution equation for the distribution function of radius of the braking drops is written to be an invariant under the group of scaling transformations. Due to this symmetry, it turns out that it is possible to obtain an asymptotic solution and to reduce the evolution equation to the Fokker-Planck type in the long-time limit. The asymptotic solution is a log-normal distribution. This asymptotic solution goes to the power distribution in a broad range of radius. The fractal dimension of the power distribution appears to be consistent with the irregular fragmentary nature of the atomization process. The kinetic equation for the complete distribution function F (x,v.r,l) of liquid particles in the phase space of droplet position, velocity and radius is written.

The present contribution gives an overview of the use of different simulation tools for the optimization of injection parameters of a diesel engine. With a one-dimensional tool, the behavior of the mechanics and fluid dynamics of the entire injection system is calculated. This simulation provides information on the dynamic needle lift, injection rates, pressures, etc. The flow within the injector is simulated using a three-dimensional CFD tool. By use of a two-phase model, it is possible to analyze the cavitating flow inside the injector and to calculate the effective nozzle hole area as well as the exit flow characteristics. Mixture formation, combustion and pollutant formation simulation is performed adopting three-dimensional CFD. In order to provide the initial and boundary conditions for the engine CFD simulation and to optimize the engine cycle performance a one-dimensional tool is adopted.

High pressures and pressure gradients appear in the combustion chamber during the combustion process. The plunger-barrel assembly described in this paper comes up with a trick to circumvent this defect: it generates the mechanical two-stage fuel injection. Due to its special construction, the plunger-barrel assembly allows a small amount of fuel to flow into the cylinder just a few milliseconds prior to main injection. The role of the new fuel injection system is highlighted through the comparison between research results (computer simulation, injection bench and engine tests) obtained after investigating conventional and two-stage fuel injection pumps for naval use.

Multiple injection is potentially capable of reducing emissions of common-rail diesel engines at part load. The slope of the needle lift of today’s hydraulically operated common-rail injectors is very weak. For that reason, the fuel flow is throttled in that phase and the mixture formation suffers. The presented injector, which is directly actuated by a piezo, shows the same very steep needle lift as a unit injector. This results in a better mixture formation. A needle lift control allows to open orifices at different levels and to adjust homogenisation. The hardware in the loop simulation shows the exact needle lift control and its influence on the mixture formation.

The paper gives a short outline of experiences gained at IM in the design of an electromechanical valve actuator having two magnets and two balanced springs. This device works at fixed lift, fixed lifting time and variable valve event. Some of most relevant topics regarding the design of such a type of actuator have been analyzed. In particular, in the first part of the paper the problems of varying load have been tackled with the aid of a commercial one-dimensional code. Based on these results, the electromechanical design of the actuator has been started. Three axial-symmetric geometries have been compared using an electromagnetic CAD. The requirements of systems to perform the first lift at engine start up and the catching in operation have been analyzed. The evaluation of energy losses connected with these phases has been also done.