ElsevierBermúdez Tamarit, VR.; Lujan Martinez, JM.; Climent Puchades, H.; Campos, D. (2015). Assessment of pollutants emission and aftertreatment efficiency in a GTDi engine including cooled LP-EGR system under different steady-state operating conditions. Applied Energy. AbstractNowadays, EGR systems are being incorporated in the research focused on spark-ignition direct-injection engines as a solution to the problems presented by them; i.e. knock risk and high combustion temperature which produces high NOx emission. Since the major part of the investigations are centered on engine performance or engine simulation aside pollutants emission and aftertreatment evaluation, this paper focuses on these topics: gaseous and particle emission analysis and aftertreatment efficiency evaluation when cooled LP-EGR system is applied to a GTDi engine.This work has been performed in a 4-cylinder, turbocharged, direct-injection gasoline engine with 2.0 L displacement. The equipment used in this study are TSI-EEPS for particle measurement and HORIBA MEXA 1230-PM for soot measurement being HORIBA MEXA 7100-DEGR with a heated line selector the system employed for regulated gaseous emission measurement and aftertreatment evaluation. A reduction around 50% of NOx with an increase of HC and CO emissions was found in medium-load operating points. At full-load conditions, the suppression of fuel enrichment including EGR leads in a drastically reduction in CO maintaining similar HC and NOx emissions.Furthermore, PN and soot emissions also decrease as EGR is included and spark timing advanced in all the tested conditions.

ElsevierBermúdez Tamarit, VR.; Lujan Martinez, JM.; Ruiz Rosales, S.; Campos, D.; Linares Rodríguez, WG. (2015). New European Driving Cycle assessment by means of particle size distributions in a light-duty diesel engine fuelled with different fuel formulations. Fuel. 140:649-659. doi:10.1016Fuel. 140:649-659. doi:10. /j.fuel.2014 AbstractIn this study, an experimental investigation of particle size distribution emission over performance of transient conditions in a high speed diesel engine fuelled with diesel, biodiesel and Fischer Tropsch fuels have been assessed.Six fuels with different properties have been tested in a 4-cylinder light-duty diesel engine typically used for European passenger cars. The cycle used in this study was the New European Driving Cycle (NEDC) and each test was carried out after a stabilization warming period in order to avoid cold start effects. A comparative analysis between nucleation and accumulation particle mode concentration, particle size distributions and a geometric mean diameter calculation are presented in this paper. In this sense, a reduction in the range of particle diameter emitted and a decrease in accumulation particle mode concentration with Fischer Tropsch fuel during the EUDC were found. In contrast, all biofuels used show an increase of particle number concentration in nucleation-mode during the urban cycles (ECE-15) related to combustion damage at low load conditions. Finally, an increase in the sulfur content diesel fuel leads to an increase in the geometric mean diameter of particle size distribution related to the increase in accumulation particle concentration during the entire cycle.

Diesel particulate filters are a standard technology used in diesel engines in order to comply with actual and forthcoming regulations, regarding soot emissions and particulate matter in exhaust gases. In recent years, pre-turbo aftertreatment response has been investigated as opposed to the traditional aftertreatment location downstream from the turbine but just regarding engine performance. Previous studies do not deal in detail with gaseous and particle emission analisys in a pre-turbo aftertreatment configuration. This paper focuses on these topics. The gaseous pollutant and particle emissions have been assessed in a 4-cylinder, light-duty diesel EURO 4 engine typically used in European passenger car vehicles. Different steady-state operating points have been considered in order to extend the study over a wide range of operating conditions. Additionally, the New European Driving Cycle has been performed with the aim of reaching a comprehensive understanding of the aftertreatment dynamic response in terms of pollutant emissions. An increase in the amount of NO 2 converted from NO and a reduction in emitted CO have been found at low load steady-state operating conditions with pre-turbo aftertreatment placement. In driving cycle conditions, a shift from nucleation to accumulation mode particles have been found, being the filtration efficiency scarcely affected.

The pressure drop across diesel particulate filters directly affects the exhaust back-pressure and the fuel economy of internal combustion engines. Such a pressure drop is related to the soot trapped inside the DPF so that the exhaust back-pressure increases as the soot mass loading does. Consequently regeneration strategies are required in order to remove the soot collected at the DPF. However, these processes usually involves additional fuel consumption.Considering this context, new design approaches and control techniques to reduce the exhaust back-pressure dependence on DPF soot loading are arising. One technique is based on the injection of water at the DPF inlet to get a new redistribution of the particulate matter and a reduction of the DPF pressure drop. The possibility to keep constant the exhaust back-pressure by consecutive pre-DPF water injection events provides better control on tailpipe particle emissions. The aim of this paper is to establish a comprehensive analysis of the pollutant emission and particle behavior during pre-DPF water injection events. The DPF filtration efficiency and the particle size distribution are also analysed after performing a DPF loading test with pre-DPF water injection events. Results have shown a negligible transient particle emission during the pre-DPF water injection event and that there are not effects on overall filtration efficiency.

Air pollution is a relevant issue studied worldwide, and its prediction is important for social and economic management. Linear multivariate regression models (LMR) and artificial neural networks (ANN) are widely applied to forecasting concentrations of pollutants. However, unorganized machines are scarcely used. The present investigation proposes the application of unorganized machines (echo state networks - ESN and extreme learning machines - ELM) to forecast hourly concentrations of particulate matter with the aerodynamic diameter up to 10 µm (PM10), carbon monoxide (CO), and ozone (O3) at the metropolitan region of Recife, Pernambuco, Brazil. The results were compared with multilayer perceptron neural network (MLP) and LMR. The prediction was made using or not meteorological variables (wind speed, temperature, and relative humidity) as input data. The results showed that the inclusion of these variables could increase the general performance of the models considering one step ahead forecasting horizons. Also, the ELM and the LMR achieved the best overall results.

Abstract.A study of soot measurement deviation using a diffusion charger sensor with three dilution ratios enables was conducted in order to obtain a repeatable setting that can be used to obtain measurements of the particulate matter in terms of soot mass emitted by a light-duty diesel engine under transient operating conditions. The paper includes three experimental phases: an experimental validation of the measurement settings in steady-state operating conditions; evaluation of the proposed setting under the New European Driving Cycle, and a study of the correlations for different measurement techniques providing reliable correlations for estimating soot emission from opacity measurement or from accumulation particle mode concentration. There are several methods and correlations to estimate soot mass rate in the literature but most of them were assessed for steady-state operating points. In this case, the correlations are obtained by more than 4000 points measured in transient conditions. The results of soot measurements allowed by the new two correlations and deviations less that 4% to the reference measurement founded in both correlations are presented in this paper.

In order to improve performance and minimize pollutant emissions in gasoline turbocharged directinjection (GTDi) engines, different injection strategies and technologies are being investigated. The inclusion of exhaust gas recirculation (EGR) and the variation of the start of injection (SOI) are some of these strategies that can influence the air-to-fuel (AF) mixture formation and consequently in the combustion process and pollutant emissions. This paper presents a complete study of the engine performance, pollutant emissions and aftertreatment efficiency that produces the SOI variation with a fixed EGR rate in a 4-cylinder, turbocharged, gasoline direct-injection engine with 2.0 L displacement. The equipment used in this study are TSI-EEPS for particle measurement and HORIBA MEXA 1230-PM for soot measurement being HORIBA MEXA 7100-DEGR with a heated line selector the system employed for regulated gaseous emission measurement and aftertreatment evaluation. The experimental results confirm how the use of an adequate SOI strategy is indispensable to obtain low exhaust emissions values and a balance between the different pollutants. There was found a slight reduction in brake specific fuel consumption (BSFC) with the SOI advance. The experiments showed a decrease in CO, a non-sensible variation of THC and an increase in NOx emissions with SOI delay. Additionally, a significant increase in particle emissions was observed with early SOIs. Finally, with the SOI delay the aftertreatment performance revealed an increase in the oxidation of CO and a decrease in the reduction of NOx.

Many high school teachers when teaching mathe-matical content, face questions from their students about theapplicability of these contents. We will show in this paper thatit is possible to answer some of these questions by relating someof this content to optimization problems, which are modeled aslinear programming problems and solved using GeoGebra as atool.