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A Methodology for Monitoring Real-World CO2 Emissions Compliance in Passenger Vehicles

Aristotle University of Thessaloniki-Nikiforos Zacharof, Stylianos Doulgeris, Ioannis Myrsinias, Zisimos Toumasatos, Athanasios Dimaratos, Zissis Samaras
European Commission Joint Research-Georgios Fontaras
  • Technical Paper
  • 2020-37-0034
To be published on 2020-06-23 by SAE International in United States
The road transport CO2 emissions reduction scheme in the European Union foresees mandatory targets for passenger vehicles. However, several studies have shown that there is a divergence between official and real-world values that it could be up to 40% in the NEDC. The introduction of the WLTP was expected to curb this divergence, but it is uncertain whether it can fully address the problem. In order to address this issue, future legislation aims at monitoring on-road fuel consumption and subsequently CO2 emissions by utilizing on-board fuel consumption meters. The current study investigates a monitoring approach that obtains and normalizes on-road vehicle operation data and estimate CO2 emissions through vehicle simulation. The first step is to create the vehicle’s engine fuel consumption map, based on laboratory vehicle measurements in order to use it as reference data. Subsequently, a methodology is developed to produce the vehicle’s engine map from signals retrieved through the OBD port in order to emulate data availability under a monitoring scheme. The methodology to derive the vehicle’s engine fuel consumption map includes an…
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Design of the Compression Chamber and Optimization of the Sealing of a Novel Rotary Internal Combustion Engine using CFD

Aristotle University of Thessaloniki-Savvas S. Savvakis, Elias Nassiopoulos, Dimitrios Mertzis, Zissis Samaras
  • Technical Paper
  • 2020-37-0007
To be published on 2020-06-23 by SAE International in United States
The increasing demand for lower fuel consumption and pollutant emissions favours the development of novel engine configurations. In line with this demand, the present contribution aims to investigate the sealing performance of a new concept rotary split-engine with a very promising thermal efficiency, a very low NOx emissions' level, and a much higher power density than any conventional internal combustion engine can. It uses the Atkinson cycle, a low-temperature combustion process and when it uses two pistons, symmetrically positioned around its shaft, it gives one power stroke every 180 degrees. The main focus of this work is to provide all the steps followed so far in order to ensure an efficient sealing and operation of the compression process of this engine, including the 1D & CFD simulations, CAD design & optimisation, and experimental campaign for verifying the digital results. The so-far investigation and experiments conclude that this new rotary engine can work with no oil lubrication inside the compression chamber and with much lower mechanical losses compared to the existing reciprocating engines.
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A Novel 1D Co-Simulation Framework for the Prediction of Tailpipe Emissions under Different IC Engine Operating Conditions

Aristotle University of Thessaloniki-Grigorios Koltsakis, Zissis Samaras
EMPA-Panayotis Dimopoulos Eggenschwiler, Viola Papetti, Jakub Rojewski, Patrik Soltic
Published 2019-09-09 by SAE International in United States
The accurate prediction of pollutant emissions generated by IC engines is a key aspect to guarantee the respect of the emission regulation legislation. This paper describes the approach followed by the authors to achieve a strict numerical coupling of two different 1D modeling tools in a co-simulation environment, aiming at a reliable calculation of engine-out and tailpipe emissions. The main idea is to allow an accurate 1D simulation of the unsteady flows and wave motion inside the intake and exhaust systems, without resorting to an over-simplified geometrical discretization, and to rely on advanced thermodynamic combustion models and kinetic sub-models for the calculation of cylinder-out emissions. A specific fluid dynamic approach is then used to track the chemical composition along the exhaust duct-system, in order to evaluate the conversion efficiency of after-treatment devices, such as TWC, GPF, DPF, DOC, SCR and so on. This co-simulation environment is validated against a real engine configuration which was instrumented and tested at EMPA labs. A 4-cylinder SI, turbocharged, CNG engine is investigated at different loads and revolution speeds, to…
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Emissions Optimization Potential of a Diesel Engine Running on HVO: A Combined Experimental and Simulation Investigation

Aristotle University of Thessaloniki-Dimaratos Athanasios, Doulgeris Stylianos, Zissis Samaras
Centre for Research & Technology Hellas (CERTH)-Dimitriadis Athanasios, Bezergianni Stella
  • Technical Paper
  • 2019-24-0039
Published 2019-09-09 by SAE International in United States
The present work investigates a number of recalibration possibilities of a common rail turbocharged diesel engine, aiming at the improvement of its emissions performance and fuel consumption (FC), with Hydrotreated Vegetable Oil (HVO). Initially, steady-state experimental data with nominal engine settings revealed HVO benefits as a drop-in fuel. Under these conditions, pure HVO results in lower engine-out PM emissions, lower CO2 emissions, and lower mass-based FC, while the respective NOx emissions present a mixed trend. In mid loads and speeds NOx emissions of HVO are lower while at higher loads and speeds are slightly higher compared to conventional diesel. At a second step, a combustion model was developed, in order to investigate the possible re-adjustments of IT (Injection Timing) and EGR (Exhaust Gas Recirculation) settings in order to exploit HVO’s properties for further reduction of emissions and FC. The results of the combustion model in steady-state conditions showed clear reductions in NOx (up to 50%), PM (up 70%) to and CO2 (up to 7%) emissions with HVO, when IT and EGR are recalibrated compared to…
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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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