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A Model Based Definition of a Reference CO2 Emissions Value for Passenger Cars under Real World Conditions

Aristotle University of Thessaloniki-Zissis Samaras, Dimitris Tsokolis, Athanasios Dimaratos, Leonidas Ntziachristos, Stylianos Doulgeris
TNO Automotive-Norbert Ligterink, Willar Vonk, Rob Cuelenaere
Published 2018-05-30 by SAE International in United States
With the adoption of the Worldwide harmonized Light Vehicles Test Procedure (WLTP) and the Real Driving Emissions (RDE) regulations for testing and monitoring the vehicle pollutant emissions, as well as CO2 and fuel consumption, the gap between real world and type approval performances is expected to decrease to a large extent. With respect to CO2, however, WLTP is not expected to fully eliminate the reported 40% discrepancy between real world and type approval values. This is mainly attributed to the fact that laboratory tests take place under average controlled conditions that do not fully replicate the environmental and traffic conditions experienced over daily driving across Europe. In addition, any uncertainties of a pre-defined test protocol and the vehicle operation can be optimized to lower the CO2 emissions of the type approval test.Such issues can be minimized in principle with the adoption of a real-world test for fuel consumption. However, repeatability and an accuracy of a few gCO2/km is difficult to achieve due to the actual drag, the road surface effect on driving resistance, the road…
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Description of a Novel Concentric Rotary Engine

Aristotle University of Thessaloniki-Vasilis Gkoutzamanis, Zissis Samaras
theSARMproject-Savvas Savvakis
Published 2018-04-03 by SAE International in United States
The present work presents the concept of a new rotary engine, and provides first investigations for its implementation in the energy sector. The main focus of this work is to provide a theoretical description of the engine and its differences from the state-of-the-art technologies. Its innovative principle consists of concentric operation, with two pistons of different rotation radius and the addition of a third intermediate chamber between the compression and combustion chamber. A description of the engine’s physical model is provided, followed by an analysis of the selected specific geometrical features. Additionally, a thermodynamic analysis clarifies the operational advantage compared to the existing cycles and, finally, a numerical investigation on the engine’s bulk performance is provided to quantify the anticipated results of the theoretical analysis. The theoretical description concludes that the new rotary engine is characterized by simple design with the minimum possible moving parts that can be easily integrated into hybrid systems or small sized applications. Its anticipated volume and weight is five to six times smaller than that of conventional engines owing to…
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Effect of Diesel Properties on Emissions and Fuel Consumption from Euro 4, 5 and 6 European Passenger Cars

Aristotle University of Thessaloniki-Zissis Samaras, Athanasios Dimaratos
BP Europa SE-Thomas Bartsch
Published 2016-10-17 by SAE International in United States
Certain diesel fuel specification properties are considered to be environmental parameters according to the European Fuels Quality Directive (FQD, 2009/EC/30) and previous regulations. These limits included in the EN 590 specification were derived from the European Programme on Emissions, Fuels and Engine Technologies (EPEFE) which was carried out in the 1990’s on diesel vehicles meeting Euro 2 emissions standards. These limits could potentially constrain FAME blending levels higher than 7% v/v. In addition, no significant work has been conducted since to investigate whether relaxing these limits would give rise to performance or emissions debits or fuel consumption benefits in more modern vehicles. The objective of this test programme was to evaluate the impact of specific diesel properties on emissions and fuel consumption in Euro 4, Euro 5 and Euro 6 light-duty diesel vehicle technologies. The tests were conducted in two driving cycles, the New European Driving Cycle (NEDC) and the Worldwide harmonised Light duty Test Cycle (WLTC), which is considered closer to real driving and is going to be the new type approval test in…
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Development of a Template Model and Simulation Approach for Quantifying the Effect of WLTP Introduction on Light Duty Vehicle CO2 Emissions and Fuel Consumption

Aristotle University Thessaloniki-Dimitris Tsokolis, Georgios Triantafyllopoulos, Anastasios Kontses, Zisis Toumasatos, Athanasios Dimaratos
Aristotle University of Thessaloniki-Zissis Samaras
Published 2015-09-06 by SAE International in United States
The paper describes the development of a modelling approach to simulate the effect of the new Worldwide harmonized Light duty Test Procedure (WLTP) on the certified CO2 emissions of light duty vehicles. The European fleet has been divided into a number of segments based on specific vehicle characteristics and technologies. Representative vehicles for each segment were selected. A test protocol has been developed in order to generate the necessary data for the validation of the vehicle simulation models. In order to minimize the sources of uncertainty and the effects of flexibilities, a reference “template model” was developed to be used in the study. Subsequently, vehicle models were developed using AVL Cruise simulation software based on the above mentioned template model. The various components and sub-modules of the models, as well as their input parameters, have been defined with the support of the respective OEMs. Specific strategies have been defined for the implementation of individual technologies affecting fuel consumption such as Start-stop, Brake Energy Recuperation, and Variable Valve Actuation etc. Each vehicle model was validated comparing…
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Experimental Investigation of Cyclic Variability on Combustion and Emissions of a High-Speed SI Engine

Aristotle University of Thessaloniki-Apostolos Karvountzis-Kontakiotis, Leonidas Ntziachristos, Zissis Samaras, Athanasios Dimaratos
Cambustion Ltd-Mark Peckham
Published 2015-04-14 by SAE International in United States
Cyclic combustion variability (CCV) is an undesirable characteristic of spark ignition (SI) engines, and originates from variations in gas motion and turbulence, as well as from differences in mixture composition and homogeneity in each cycle. In this work, the cycle to cycle variability on combustion and emissions is experimentally investigated on a high-speed, port fuel injected, spark ignition engine. Fast response analyzers were placed at the exhaust manifold, directly downstream of the exhaust valve of one cylinder, for the determination of the cycle-resolved carbon monoxide (CO) and nitric oxide (NO) emissions. A piezoelectric transducer, integrated in the spark-plug, was also used for cylinder pressure measurement. The impact of engine operating parameters, namely engine speed, load, equivalence ratio and ignition timing on combustion and emissions variability, was evaluated. The variations in mixture stoichiometry were found to have a strong effect on engine combustion variability. Rich cyclic mixture compositions exhibit lower coefficient of variation (COV) for the indicated mean effective pressure (IMEP) and NO emissions (COVNO) compared with lean mixtures. The mean value of CO emission was…
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Use of a PPS Sensor in Evaluating the Impact of Fuel Efficiency Improvement Technologies on the Particle Emissions of a Euro 5 Diesel Car

Aristotle University of Thessaloniki-Stavros Amanatidis, Leonidas Ntziachristos, Zissis Samaras
EMISIA SA-Chariton Kouridis
Published 2014-04-01 by SAE International in United States
The effect of “Start & Stop” and “Gear Shift Indicator” - two widespread fuel saving technologies - on fuel consumption and particle emissions of a Euro 5 passenger car is evaluated in this paper. The vehicle was subjected to a series of different driving cycles, including the current (NEDC) and future (WLTC) cycles implemented in the European type approval procedure at cold and hot start condition and particle number was measured with an AVL Particle Counter. In addition, we have utilized two Pegasor Particle Sensor units positioned in different locations along the sampling line to assess the impact of the sampling location on the particle characteristics measured during highly transient events.The results showed that the particle number emission levels over the WLTC were comparable to the NEDC ones, whereas NOx emissions were more than twofold higher. Both fuel saving technologies can lead to reduced fuel consumption and, subsequently CO2 emissions, in the order of 5%. However, their impact on particle emissions was not straightforward, as the impact of the DPF loading was found much more…
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Impact of FAME Content on the Regeneration Frequency of Diesel Particulate Filters (DPFs)

SAE International Journal of Fuels and Lubricants

Aristotle University of Thessaloniki-Dimitris Katsaounis, Christos Samaras, Savas Geivanidis, Zissis Samaras
Concawe-Kenneth Rose, Heather Hamje, Liesbeth Jansen, Corrado Fittavolini, Richard Clark, Maria Dolores Cardenas Almena
  • Journal Article
  • 2014-01-1605
Published 2014-04-01 by SAE International in United States
Modern diesel vehicles utilize two technologies, one fuel based and one hardware based, that have been motivated by recent European legislation: diesel fuel blends containing Fatty Acid Methyl Esters (FAME) and Diesel Particulate Filters (DPF). Oxygenates, like FAME, are known to reduce PM formation in the combustion chamber and reduce the amount of soot that must be filtered from the engine exhaust by the DPF. This effect is also expected to lengthen the time between DPF regenerations and reduce the fuel consumption penalty that is associated with soot loading and regeneration.This study investigated the effect of FAME content, up to 50% v/v (B50), in diesel fuel on the DPF regeneration frequency by repeatedly running a Euro 5 multi-cylinder bench engine over the European regulatory cycle (NEDC) until a specified soot loading limit had been reached. The results verify the expected reduction of engine-out particulate mass (PM) emissions with increasing FAME content and the reduction in fuel economy penalty associated with reducing the frequency of DPF regenerations. Fuel dilution measurements on lubricant samples taken from the…
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Applicability of the Pegasor Particle Sensor to Measure Particle Number, Mass and PM Emissions

Aristotle University of Thessaloniki-Stavros Amanatidis, Leonidas Ntziachristos, Zissis Samaras
Pegasor Oy-Kauko Janka, Juha Tikkanen
Published 2013-09-08 by SAE International in United States
The Pegasor Particle Sensor (PPS) has been earlier presented by Ntziachristos et al. (SAE Paper 2011-01-0626) as a novel small and robust instrument that can be directly installed in the exhaust line to measure exhaust particles without any dilution. The instrument is based on the electrical detection of aerosol. It is increasingly being used to measure exhaust particles from engines and vehicles with different exhaust configurations. In this study, a number of tests have been conducted using two sensors in parallel, one directly installed in the tailpipe and one installed in the CVS, side by side to the PM sampling filter. Aim of the study was to make recommendations on the proper use of the sensor and to check how the sensor signal compares to particulate mass, soot concentration, and particle number. A first finding is that external heating has to be provided to the sensor to avoid condensation. Second, very good linearity of the sensor signal is established for all three particle concentrations examined. The only exception was PM at very low concentrations, where…
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SCR System Optimization and Control Supported by Simulation Tools

Aristotle University of Thessaloniki-Grigorios C. Koltsakis, Pavlos Fragkiadoulakis, Zissis Samaras
Exothermia SA-Christos Manetas
Published 2013-04-08 by SAE International in United States
The successful design and especially the control of the SCR system is a challenging process that can be supported by the application of simulation tools. As a first step, we employ physico-chemically informed ‘off-line’ models that are calibrated with the help of targeted small- and full-scale tests. Despite their high level of sophistication, this SCR model is able to be integrated in a control-oriented simulation software platform and connected to other powertrain simulation blocks. The target is to use this simulation platform as a virtual environment for the development and optimization of SCR control strategies. The above process is demonstrated in the case of a passenger car SCR. The model is calibrated at both fresh and aged catalyst condition and validated using experimental data from the engine bench under a wide variety of operating conditions. Next, the calibrated model was coupled with embedded control models, developed for Euro 6 passenger car powertrains. The final simulation platform enabled the precalibration and optimization of dosing control strategies, saving significant experimental effort and costs. Finally, it allowed the…
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Application of the Pegasor Particle Sensor for the Measurement of Mass and Particle Number Emissions

SAE International Journal of Fuels and Lubricants

Aristotle University of Thessaloniki-Leonidas Ntziachristos, Stavros Amanatidis, Zissis Samaras
Pegasor Oy-Kauko Janka, Juha Tikkanen
  • Journal Article
  • 2013-01-1561
Published 2013-04-08 by SAE International in United States
The Pegasor Particle Sensor (PPS) is a small and lightweight sensor that can be used directly in raw exhaust to provide the mass and number concentration of exhaust aerosol. Its operation principle is based on the electrical charging of exhaust aerosol and determination of particle concentration by measuring the charge accumulated on the particles. In this paper we have applied the PPS in a variety of vehicle exhaust configurations to evaluate its performance characteristics. First, the output signal of the instrument was calibrated with diesel exhaust to deliver either the mass or the number concentration of exhaust aerosol. Linear response with the soot mass concentration measured by a Photo Acoustic Soot Sensor and number concentration measured by an Electrical Low Pressure Impactor was established. Based on this calibration, the instrument was then used to measure particle concentrations at levels produced by a gasoline direct injection vehicle and diesel exhaust filtered by particle filters of variable efficiency. Hence, the complete range of concentrations and particle characteristics typically encountered in automotive exhaust has been examined. The results…
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