Homogeneous Charge Compression Ignition Research Articles

Development of a fast-virtual CFR engine model and its use on autoignition studies

Homogenous charge compression ignition engines have been studied as an alternative to the conventional diesel combustion to attain high efficiency with ultra-low NOx and soot emissions for a wide variety of fuels. However, its usage in real applications has been restricted due to the difficulties regarding combustion control and operating range extension. The modification of the fuel characteristics may be a pathway to solve the previous hurdles. Therefore, this research presents a relevant methodology to assess the fuel response to HCCI boundary conditions based on 0-D and 1-D modelling for detailed chemistry solution and state conditions definition, respectively. The results suggest that the methodology can predict the early stages of the fuel oxidation with good accuracy. For the objective of predicting the start of combustion, the best results are obtained using tabulated chemistry when investigating fuels that have pre reactions and a low temperature heat release. As the oxidation process progresses, the deviation of the pressure-temperature trajectory from non-reactive to reactive conditions after the low temperature heat release decreases the predictive capability to some extent. Nonetheless, the methodology outcomes are still valid as a qualitative metric for reactivity determination as well as the intermediate and high temperature ignition delay.

Validation of Kinetic Mechanisms against Various Ignition Delay Data and the Development of Ignition Delay Correlations for Ethanol, Natural Gas, and Primary Reference Fuel Blends under Homogeneous Charge Compression Ignition Conditions

Validation of Kinetic Mechanisms against Various Ignition Delay Data and the Development of Ignition Delay Correlations for Ethanol, Natural Gas, and Primary Reference Fuel Blends under Homogeneous Charge Compression Ignition Conditions

Role of hydrogen in improving performance and emission characteristics of homogeneous charge compression ignition engine fueled with graphite oxide nanoparticle-added microalgae biodiesel/diesel blends

The development of low-temperature combustion models combined with the use of biofuels has been considered as an efficient strategy to reduce pollutant emissions like CO, HC. NOx, and smoke. Indeed, Homogeneous Charge Compression Ignition (HCCI) is the new approach to drastically minimize NOx emissions and smoke owing to the lower cylinder temperature and a higher rate of homogeneous A/F mixture as compared to compression ignition (CI) engines. The present research deal with the behavior analysis of a CI engine powered by diesel, Euglena Sanguinea (ES), and their blends (ES20D80, ES40D60, ES60D40, ES80D20). The experimental results revealed the highest brake thermal efficiency for ES20D80 although it decreased by 4.1% compared to diesel at normal mode. The average drop in HC, CO, and smoke was 2.1, 2.3, and 5.7% for ES20D80 as opposed to diesel fuel. Therefore, in the next stage, ES20D80 with various concentrations of graphite oxide (GO) nanoparticle (20, 40, 60, and 80 ppm) was chosen to carry out experiments in the HCCI mode, in which hydrogen gas was induced along with air through the intake pipe at a fixed flow rate of 3 lpm for the enrichment of the air-fuel mixture. As a result, the combination of hydrogen-enriched gas and GO-added ES20D80 in the HCCI mode showed similar performance to the CI engine but registered a major reduction of NOx and smoke emissions, corresponding to 75.24% and 53.07% respectively, as compared to diesel fuel at normal mode.

Auto-ignition of polyoxymethylene dimethyl ether 3 (PODE3) blended with diesel and gasoline via combustion under homogeneous charge compression ignition

• PODE 3 /diesel/gasoline blends in a HCCI engine are studied for the first time. • High temperature kinetic reactions are dependent on cetane number of fuel blend. • Oxygen from PODE 3 helps promote better ignition when gasoline is added to PODE 3 . • Gasoline addition to PODE 3 presents higher efficiency than diesel addition. • PODE 3 demonstrates high potential in encouraging clean combustion. With high oxygen content and cetane number, PODE 3 is a favorable renewable fuel for engines. PODE 3 /diesel/gasoline blends in a HCCI engine are numerically studied for the first time. The effects of fuel blend ratio and equivalence ratio (ER) on auto-ignition are investigated. A highly compact and robust chemical mechanism has been implemented. Crank angle at which 50 percent of heat is released (CA50) displays higher sensitivity towards blend ratio in leaner mixtures with 50% PODE 3 displaying a change of 12.31 CAD at 0.34 ER and only 6.19 CAD at 0.5 ER when made in comparison to their respective CA50 at 100% PODE 3 . Furthermore, indicated thermal efficiency (ITE) is observed to be better with higher ER with 100% PODE 3 having a 23.3% increase in ITE at 0.5 ER than at 0.34 ER, and is generally higher with increased PODE 3 . Neat PODE 3 displays lowest CO and highest CO 2 for all cases, manifesting high oxidation reactivity. Additionally, acetylene levels are substantially lower for combustions at 0.5 ER as compared to 0.34 ER. Lastly, PODE 3 yields only 2.04 × 10 −10 g/cycle and 5.67 × 10 −11 g/cycle of C 2 H 2 at 0.34 ER and 0.5 ER respectively. With nearly no soot precursors, PODE 3 demonstrates high potential in encouraging clean combustion.

Development and validation of a n‐butanol reduced chemical kinetic mechanism under engine relevant conditions

AbstractA n‐butanol reduced mechanism (60 species and 306 reactions) was developed using the direct relation graph with error propagation and isomer lumping methods. Sensitivity analysis (SA) was then performed to identify reactions that were sensitive to the ignition delay (ID) for the adjustments of the pre‐exponential factor to replicate the experimental ID times. As compared with the experimental measurements at initial temperatures of 343–1350 K, initial pressures of 0.02–80 bar, and equivalence ratios of 0.5–2.0, the maximum deviation for the predictions by the n‐butanol reduced mechanism was at 37.75% for the ID times, 8 cm/s for the laminar flame speed, and a factor of three for both the species concentration profiles under jet‐stirred reactor and premixed laminar flame. Furthermore, a maximum deviation of 2.5 crank angle degrees in combustion phasing was obtained when the reduced mechanism was benchmarked against the detailed mechanism under homogeneous charge compression ignition (HCCI) conditions at initial temperature of 413 K, initial pressure of 1 bar, and equivalence ratios of 0.5–2.0. Despite these deviations, the low temperature IDs and the laminar flame speed predicted by the present reduced mechanism were in better agreement to the experimental measurements than the existing n‐butanol reduced mechanisms of comparable sizes. Hence, this collectively indicates that improvements were made to the present reduced mechanism, particularly for the low‐temperature reactions. The n‐butanol reduced mechanism was also compared with gasoline and diesel surrogates under 0D HCCI simulations. The results indicate that the combustion characteristics of n‐butanol is closer to gasoline than to diesel. This suggests that n‐butanol could safely replace gasoline fuel in neat form while it is more suitable to be blended with diesel fuel to maintain engine performance and prevent any adverse effects on the engine.

Optimization of Valve Profile for a Homogeneous Charge Compression Ignition Engine

İçten yanmalı motorların giderek sıkılaşan emisyon standartları dolayısıyla, farklı konseptlerle yanma gerçekleştirilmesi ve emisyonlarının azaltılması amaçlanmaktadır. Homojen dolgulu sıkıştırma ateşlemeli motorlarda, görece düşük sıcaklıklarda yanma meydana geldiğinden dolayı, çok düşük NOX ve is emisyonları açığa çıkmaktadır. Ancak yanma prosesi, vuruntusuz ve teklemesiz olarak gerçekleşebilmesi için motorun iyi bir şekilde kontrol edilmesi ve bütün parametrelerinin optimize edilmesi gerekmektedir. Bu çalışmada, homojen dolgulu sıkıştırma ateşlemeli dizel yakıtlı bir motorun, bu yeni nesil yanma stratejisine uygun olarak supap profili bir boyutlu yanma modeli ve genetik algoritma kullanılarak optimize edilmiştir. Supap açılma ve kapanma krank açıları parametrik olarak değiştirilmiştir. Ayrıca, supap profilinin tamamen açıldığı noktaya bekleme eklenmiştir. Böylelikle, volümetrik verim artışı hedeflenmiş ve fren gücü değeri maksimize edilmiştir. Tasarlanan yeni supap profili ile motor fren gücü %28 artarken, özgül yakıt tüketimi değeri %6 azalmıştır.

Important Contributions to Reducing Nitrogen Oxide Emissions from Internal Combustion Engines.

Nitrogen oxides are considered significant pollutants because of their effects on ecosystems and human health. The amount of NOx emitted by internal combustion engines can be reduced, mostly by acting on the conditions in which combustion takes place, respectively by lowering the peak flame temperature, reducing the excess of oxygen, etc. The homogeneous charge compression ignition (HCCI) engine represents a new technology that can simultaneously reduce NOx emissions and fuel consumption. This article presents these benefits of the HCCI engine by comparing the emissions and fuel consumption of a monocylinder engine when it is operated in a conventional way, with spark ignition, with those obtained when the engine is running in the HCCI mode. Moreover, since engine simulation has become an important tool for investigating the HCCI process and for developing new control strategies for it, this was used in this study to determine the effects of the exhaust gas recirculation on the combustion quality, respectively, on emissions.

Experimental analysis of late direct injection combustion mode in a compression-ignition engine fuelled with biodiesel/diesel blends

A compression ignition reciprocating internal combustion engine has been modified to allow operation with late direct injection of rapeseed biodiesel fuel blends. The purpose of these modifications is to reduce both the engine's carbon footprint and emission of nitrogen oxides and soot, without decreasing performance or using expensive emission post-treatment systems. The experimental part of this work is based on the measurement of the main pollutants being emitted and the analysis of the combustion process, which is accomplished by the study of the heat release rate curve. This curve is derived from the experimental chamber pressure data, in combination with a zero-dimensional thermodynamic model assuming a perfect mixing reactor with temporal variation in volume and chemical composition, temperature-dependent properties and heat losses. The analysis of the experimental results allows deepening the knowledge of the combustion process in a compression ignition engine with late direct injection using different biodiesel blends. There is a significant reduction (>50%) of emissions of nitrogen oxides in comparison with the original configuration. This allows considering the modified configuration as an advanced combustion mode, intermediate between conventional compression ignition engines and homogeneous charge compression ignition combustion mode.

Influence of syngas composition on combustion and emissions in a homogeneous charge compression ignition engine

Homogeneous charge compression ignition (HCCI) is a promising combustion concept that can simultaneously achieve high efficiency and low nitrogen oxides (NOx) emissions. Synthesis-gas (syngas)-fueled HCCI engines can be adapted for a wide range of fuel compositions. The aim of this study was to investigate the combustion and emissions of an HCCI engine with various syngas compositions. The baseline syngas contained 30% H2, 25% CO, and 45% CO2 by volume, which provided a low heating value (LHV) of 6.08 MJ/Nm3. The fuel composition varied from hydrogen-rich to lean. It was found that syngas with an LHV of 3.34 MJ/Nm3 could be auto-ignited by implementing intake boosting with sufficient intake heating. The intake temperature required to achieve autoignition was reduced at higher loads. The start of combustion temperature mainly relied on the intake temperature and fueling rate, regardless of the fuel composition. A higher H2 content in the fuel facilitated fast burning with good combustion stability, even under lean conditions. It was revealed that a higher CO fraction deteriorated the combustion stability on the lean side with slow burning. The gross indicated thermal efficiency (ITEg) increased with an increase in the LHV of the syngas, with an ITEg of 38.1% realized at a low load of 0.3 MPa for the base fuel, while maintaining engine stability. The combustion efficiency was greater than 90% for the fuels examined at a higher fuel rate. The NOx emissions were very low because of the ultra-lean, diluted charge used for HCCI combustion.

Effects of light naphtha utilization on engine performance in an homogeneous charged compression ignition engine

In the current study, the effects of light naphtha utilization were experimentally investigated in a diesel engine operated with HCCI mode. Engine load, fuel consumption, in-cylinder pressure and emissions were measured in the experiments. 100 % light naphtha, 90% light naphtha +10% gasoline, 80% light naphtha +20% gasoline, 70% light naphtha +30% gasoline and 50% light naphtha +50% gasoline fuel blends were used as test fuels. Experiments were conducted between 7 and 14 ms injecton duration and 1100 and 1900 rpm engine speed with the intervals of 0.5 ms and 200 rpm respectively. The lowest fuel consumption was obtained as 584.42 g/kWh at 1500 rpm and 2.39 air excess coefficient with 90% light naphtha +10% gasoline and 12.5 ms injection duration. The highest engine torque was measured as 4.18 Nm at 1500 rpm and 2.31 air excess coefficient with 80% light naphtha +20% gasoline test fuel and 13.5 ms injection duration. Almost zero NO emission was observed for all HCCI operating conditions.

A DNS study of ignition characteristics of a lean PRF/air mixture with [formula omitted]O and H[formula omitted]O[formula omitted] addition under HCCI combustion-relevant conditions

The effects of additive injection including CH2O and H2O2 on the ignition characteristics of a lean primary reference fuel (PRF)/air mixture under homogeneous-charge compression ignition (HCCI) combustion conditions are investigated using 2-D direct numerical simulations (DNSs) with a 116-species reduced chemical mechanism. The 2-D DNSs of HCCI combustion are performed by varying the type and amount of the additives with a pseudo-species model and a compression-heating/expansion-cooling model. It is found that the first-stage and main ignitions are retarded by CH2O addition while the latter is promoted by H2O2 addition. By adjusting the amounts of dual additives, the main ignition can be manipulated to occur at a specific time similar to that with no additives while its mean heat release rate becomes more distributed over time than that with no additives. Combustion mode analysis reveals that a mixed mode of combustion occurs during the late phase of HCCI combustion with CH2O addition or dual additives, while spontaneous ignition mode of combustion is predominant for cases with H2O2 addition or no additives. Displacement speed analysis also verifies that CH2O addition induces deflagration rather than spontaneous ignition at the reaction fronts, which consequently leads to a smooth ignition of the RPF/air mixture. In addition, chemical explosive mode analysis (CEMA) identifies important variables and elementary reactions for low-, intermediate-, and high-temperature chemistries for the ignition of PRF/air mixture with and without additives.

Study on combustion control of a methanol SICI engine

Spark induced compression ignition (SICI) combined mode combustion can effectively solve the problems existing in homogeneous charge compression ignition (HCCI) combustion, and expand its operation range. The SICI combined combustion of methanol is divided into two combustion stages and has the characteristics of spark ignition (SI) and compression ignition (CI) combustion modes at the same time. This paper studies the SICI combustion mode of methanol from two aspects: simulation and experiment. The simulation results show that with the increase of the wall temperature, it indirectly affected the SICI combined mode combustion by affecting the hot atmosphere in the cylinder, which shortened the whole combustion duration, the SI and CI duration, it had little effect on the combustion ratio of SI and CI. The bench test results show that the methanol engine can obtain stable SICI combined mode combustion mode under the conditions of appropriate intake temperature and suitable ignition timing. From the comparison of three combustion modes of methanol, the results show that the cyclic variability of SICI combustion is the smallest. With the increase of inlet air temperature and the delay of ignition, the BP of SICI combustion at methanol starting point moves backward, the CI combustion rate decreases, but the SI combustion duration changes slightly, and the compression ignition ratio decreases. In the SICI combustion mode of methanol engine, with the increase of intake temperature, NOx emission increases, HC and CO emission decreases. With the advance of ignition timing, CO emission decreases, HC and NOx emission increases.

Investigation into engine performance of a hydrogen-dimethyl ether spark-ignition engine under various dimethyl ether fractions

Spark-ignition combustion mode could be used to widen the operation range of homogeneous charge compression ignition combustion mode on a hydrogen-dimethyl ether (DME) engine. To improve power output and reduce nitrogen oxides emissions, this study investigated the combustion and emissions properties of a hydrogen-DME spark-ignition engine under various DME fractions (αDME). The result showed that flame development and propagation periods were extended after DME blended. The increases of both periods were 1.7 and 2.0 °CA when αDME various from 1.4% to 3.0%, respectively. However, when αDME increased to 3.4%, flame propagation period had a 1.7 °CA reduction because of the spontaneous high-temperature oxidation of a few end unburned mixtures. Blending DME could improve power output of the neat hydrogen engine. The maximum improvement of indicated mean effective pressure could achieve 18.3%, after DME addition. Because of the weakened flame kernel and flame propagation process, when αDME lower than 3.0%, blending DME increased cyclic variation yet the variations were in 0.13%. Nitrogen oxides emissions could be reduced significantly, when DME was added into the neat hydrogen engine. The maximum reduction could achieve 49.9%, based on neat hydrogen fuel-supply mode. Hydrocarbon and carbon monoxide emissions were increased after DME addition. When αDME increased from 1.4% to 3.4%, the enhancement of hydrocarbon emissions was about two-third lower than that of carbon monoxide emission.

Control-oriented modeling of the gas exchange process in rebreathing homogeneous charge compression ignition engines

The purpose of this study is to develop a model for the gas exchange process in a rebreathing homogeneous charge compression ignition (HCCI) engine. HCCI engines are attracting significant attention due to their low emissions and high efficiency. To design the control system of an HCCI engine, it is necessary to develop a control-oriented engine model. The developed model lowers its computational load by combining two types of models. The model consists of a discrete model for the exhaust process (the first half of the gas exchange process) and a continuous model with a variable calculation step size for the rebreathing process (the latter half of the gas exchange process). Also, the constructed model maintained its prediction accuracy, as the pressure pulsation in the exhaust port was modeled, and an unsteady flow equation was used. It was confirmed that the model developed for the gas exchange process calculated in about half time of one cycle and reproduced the results of 1D engine simulation software with a maximum error of about 10% in the in-cylinder pressure, temperature, and trapped mass.

Experimental Investigation on Emission Characteristics of Diesel N-Pentanol Blend in Homogeneous Charged Compression Ignition Engine

The invention of internal combustion engines is undoubtedly one of the greatest inventions of the modern era. There has been steady scientific research to look for alternative fuel which is economical, renewable and less harmful to nature and man compared to fossil fuels. The present project is one such experimental work to investigate the performance of a blend of diesel / N-pentanol in an appropriate combustion technique and to establish its suitability as a renewable fuel. The relative performance of diesel fuel and the blend of diesel / n-pentanol will also be analyzed. Diesel fuel blended with 30 percentage n-pentanol is the fuel blend that is proposed to be used in the experiment. Researchers have established that the application of Homogeneously Charged Compression Ignition (HCCI) technique could result in in-cylinder reduction of NOx and PM. Higher thermal efficiency could also be attained. The project also covers studying the emission effect of the diesel/n-pentanol fuel blend for various fuel injection timing, various fuel injection pressure, different EGR rates and different inlet air temperature.

A novel design of power-cooling cogeneration system driven by solid oxide fuel cell waste heat in ocean-going vessels

Among many global energy and environmental problems, the ocean and air pollution caused by ocean-going vessels cannot be ignored. Cleaner and more efficient power generation systems should be used to replace traditional diesel generators on ships. To this problem, the combination of fuel cell and waste heat recovery technology can become a better choice. In this paper, a novel power-cooling cogeneration system is designed and analyzed, which is mainly composed of solid oxide fuel cell, preheating subsystem, homogeneous charge compression ignition engine and double-effect absorption refrigeration cycle. The study mainly includes mathematical modeling, reliability verification of each subsystem, numerical simulation and results analysis in energy, exergy and economics. The results show that the system thermal efficiency and exergy efficiency can reach 64.01% and 61.83%, respectively, which are 18.76% and 12.62% higher than those of simple cell. Compared with traditional combined system, the payback time of the proposed scheme is about 2.59 years, which not only proves that the cost can be recovered in a short time, but also shortened by about half. By improving energy efficiency and reducing costs, the proposed scheme can ensure the demand of electricity and cold energy in daily life of the crew, and provides a new choice for the marine auxiliary power generation equipment.

Emissions from homogeneous charge compression ignition (HCCI) engine using different fuels: a review.

The main objective of this paper is to review the emission characteristics of homogeneous charge compression ignition (HCCI) engines using different fuels and additives. Additionally, the impacts of various operating conditions on HCCI engine emissions are also analyzed. There is a demand faced by the engine and car manufacturers for high fuel efficiency and low emission from both consumers and the government. HCCI is an alternative internal combustion technology that is more efficient and cleaner than traditional combustion techniques. In this engine, fuel and oxidiser (typically air) are entirely mixed and compressed to the point of auto-ignition. It is a new combustion concept that provides high efficiency and resolves high nitrogen oxide (NOx) and particulate matter (PM) emissions simultaneously. Conventional diesel engine emits NOx around 2000-2500 ppm which is a primary concern; however, when diesel is used in HCCI engine, it reduces NOx to only 70-400 ppm. Furthermore, natural gas cannot be used as fuel in the conventional engine but can be used in HCCI engine. It helps reduce NOx emission even below 10 ppm. This paper reviews several works done by researchers on HCCI engines to reduce their emissions and benefit future research.

Effect of Intake Air Temperature and Premixed Ratio on Combustion and Exhaust Emissions in a Partial HCCI-DI Diesel Engine

Homogeneous charge compression ignition (HCCI) is considered an advanced combustion method for internal combustion engines that offers simultaneous reductions in oxides of nitrogen (NOx) emissions and increased fuel efficiency. The present study examines the influence of intake air temperature (IAT) and premixed diesel fuel on fuel self-ignition characteristics in a light-duty compression ignition engine. Partial HCCI was achieved by port injection of the diesel fuel through air-assisted injection while sustaining direct diesel fuel injection into the cylinder for initiating combustion. The self-ignition of diesel fuel under such a set-up was studied with variations in premixed ratios (0–0.60) and inlet temperatures (40–100 °C) under a constant 1600 rpm engine speed with 20 Nm load. Variations in performance, emissions and combustion characteristics with premixed fuel and inlet air heating were analysed in comparison with those recorded without. Heat release rate profiles determined from recorded in-cylinder pressure depicted evident multiple-stage ignitions (up to three-stage ignition in several cases) in this study. Compared with the premixed ratio, the inlet air temperature had a greater effect on low-temperature reaction and HCCI combustion timing. Nonetheless, an increase in the premixed ratio was found to be influential in reducing nitric oxides emissions.

Effect of swirl ratio on charge convection, temperature stratification, and combustion in gasoline compression ignition engine

Various low-temperature combustion strategies (namely, homogeneous charge compression ignition, reactivity controlled compression ignition, and partially premixed charge compression ignition) have shown the potential to comply with upcoming and prevailing stringent emissions legislations. Low octane gasoline has emerged as an ideal fuel candidate for premixed charge combustion under diesel-like conditions in gasoline compression ignition (GCI) engines. GCI is an excellent technology to rectify future global energy demand imbalance, because it aims to replace diesel (which is in short supply) with low octane fractions/naphtha (which is in surplus supply) in compression ignition engines. However, this novel combustion concept requires modifications in the conventional design of diesel engines. The combustion chamber shape and in-cylinder flows play a crucial role in charge distribution and temperature stratification. Therefore, understanding the combined effect of combustion chamber geometry and in-cylinder flows is essential for future engine designs. GCI combustion engine simulations for varying swirl ratios (SRs) were performed in CONVERGE CFD software to understand the effect of in-cylinder air motion on the mixture stratification and combustion. A 1/7th sector geometry for a conventional re-entry piston bowl was modeled and then simulated. Two different mechanisms were used for model validation. The results indicated that the large-scale flow structures govern the fuel distribution in the combustion chamber. The charge convection because of increased swirl has a substantial effect on the combustion characteristics of the engine. A distinguished ignition kernel was observed for all test cases. An interfacial region with counter-rotating vortices formed a lean mixture zone, hindering flame propagation and combustion. A lower SR, shallow depth piston, and modifications to avoid flame quenching in the squish zone need to be further investigated to optimize the engine performance.

Machine Learning-Based Identification Strategy of Fuel Surrogates for the CFD Simulation of Stratified Operations in Low Temperature Combustion Modes

Many researchers in industry and academia are showing an increasing interest in the definition of fuel surrogates for Computational Fluid Dynamics simulation applications. This need is mainly driven by the necessity of the engine research community to anticipate the effects of new gasoline formulations and combustion modes (e.g., Homogeneous Charge Compression Ignition, Spark Assisted Compression Ignition) to meet future emission regulations. Since those solutions strongly rely on the tailored mixture distribution, the simulation and accurate prediction of the mixture formation will be mandatory. Focusing purely on the definition of surrogates to emulate liquid phase and liquid-vapor equilibrium of gasolines, the following target properties are considered in this work: density, Reid vapor pressure, chemical macro-composition and volatility. A set of robust algorithms has been developed for the prediction of volatility and Reid vapor pressure. A Bayesian optimization algorithm based on a customized merit function has been developed to allow for the efficient definition of surrogate formulations from a palette of 15 pure compounds. The developed methodology has been applied on different real gasolines from literature in order to identify their optima surrogates. Furthermore, the ‘unicity’ of the surrogate composition is discussed by comparing the optimum solution with the most different one available in the pool of equivalent-valuable solutions. The proposed methodology has proven the potential to formulate surrogates characterized by an overall good agreement with the target properties of the experimental gasolines (max relative error below 10%, average relative error around 3%). In particular, the shape and the end-tails of the distillation curve are well captured. Furthermore, an accurate prediction of key chemical macro-components such as ethanol and aromatics and their influence on evaporative behavior is achieved. The study of the ‘unicity’ of the surrogate composition has revealed that (i) the unicity is strongly correlated with the accuracy and that (ii) both ‘unicity’ and accuracy of the prediction are very sensitive to the high presence of aromatics.