The Engine Combustion Network (ECN) community has greatly contributed to improve the fundamental understanding of spray atomization and combustion at conditions relevant to internal combustion engines. In this context, standardized spray experiments have been defined to facilitate the comparison of experimental and simulation studies performed in different facilities and with different models. This operating mode promotes collaborations among research groups and accelerates the advancement of research on spray. In efforts to improve the comparability of the ECN spray A experiments, it is of high importance to review the boundary conditions of different devices used in the community. This work is issued from the collaboration in the ECN France project, where two new experimental facilities from PPRIME (Poitiers) and PRISME (Orleans) institutes are validated to perform spray A experiments. The two facilities, based on Rapid Compression Machine (RCM) design, have been investigated to characterize their boundary conditions (e.g., flow velocity as well as fuel and gas temperatures). A set of standardized spray experiments were performed to compare their results with those obtained in other facilities, in particular the Constant Volume Pre-burn (CVP) vessel at IFPEN. It is noteworthy that it is the first time that RCM type facilities are used in such a way within the ECN. This paper (part 1) focuses on the facilities description and the fine characterization of their boundary conditions. A further paper (part 2) will present the results obtained with the same facilities performing ECN standard spray A characterizations. The reported review of thermocouple thermometry highlights that it is necessary to use thin-wires and bare-bead junction as small as possible. This would help to measure the temperature fluctuations with a minimal need for error corrections, which are highly dependent on the proper estimation of the velocity through the junction, and therefore it may introduce important uncertainties. Temperature heterogeneities are observed in all spray A devices. The standard deviation of the temperature distribution at the time of injection is approximately 5%. We report time-resolved temperature measurement from PPRIME RCM, performed in the near nozzle area during the injection. In inert condition, colder gases from the boundary layer are entrained toward the mixing area of the spray causing a further deviation from the target temperature. This emphasizes the importance of the temperature in the boundary (wall) layer. In reacting condition, the temperature of these entrained gases increases by the effect of the increased pressure, as the RCM has a relatively small volume. Generally, the velocity and turbulence levels are an order of magnitude higher in RCM and constant pressure flow compared to CVP vessels. The boundary characterization presented here will be the base for discussing spray behavior in the part 2 of this paper.

One of the objective of Engine Combustion Network (ECN), (https://ecn.sandia.gov/) is to provide experimental results with high accuracy in order to validate model and reach new steps in scientific understanding of spray combustion at conditions specific to engines. The ECN community defines different target conditions, experimental diagnostics and post processing methods to facilitate the comparison of experimental and simulations studies performed in different facilities or models. In this context two French laboratories propose two new facilities, based on Rapid Compression Machines to reach the ECN spray A conditions. In this paper, the results of liquid and vapour spray penetration as well as Ignition Delay (ID) and Lift-Off Length (LOL) obtained with these Rapid Compression Machines are compared to the results obtained in the Constant Volume Preburn (CVP) vessel of IFPEN. The specificities of each experimental apparatus allow to bring complementary elements of understanding like confinement effects. In non-reactive condition, the liquid and vapour sprays were characterized by Diffused-Back Illumination and Schlieren technique, and in reactive conditions, the LOL and the ID by OH* chemiluminescence. The analysis of the results with regard to the boundary conditions (temperature, velocity, confinement) make it possible to validate these two new facilities and contribute to enhance the database of ECN, highlighting the confinement effect typical of piston engine operation.

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Simulation with a basic representation of longitudinal vehicle dynamics is known to be sufficient for initial powertrain development activities related to efficiency and emissions such as concept application, optimal sizing, analysing the effects of physical and functional changes and also for defining basic control laws. However, when it comes to comprehensive analysis for efficiency improvement, minimizing instantaneous emission peaks or studying the impact of the new concepts on road safety, drivability and performance, the significance of detailed vehicle dynamics cannot be ignored. The work presented in this article defines a longitudinal vehicle dynamic modelling approach considering important characteristics such as the influence of normal load transfer on the varying grip of the front and rear wheels, the effect of wheel slip, and a complete representation of resistances encountered against vehicle motion with the objective of taking the analysis even closer to the actual driving conditions. The behaviour of this combined simulation platform under normal and extreme driving conditions seems to precisely follow the real scenario. This approach is a first step towards future analysis, optimization and controls development for improving transient powertrain aspects such as maximizing regenerative braking under heavy deceleration or optimizing road charging in P4 parallel hybrid architecture by managing wheel slip losses.

The intermediate fermentation mixture of butanol production, Acetone, Butanol and Ethanol (ABE), is increasingly considered as a new alternative fuel in CI engines due to its physical and chemical properties, which are similar to those of butanol, and its advantages of no additional cost or energy consumption due to butanol separation. In a previous study, the High-Pressure and High-Temperature (HPHT) chamber, called 'New One Shot Engine" (NOSE), was used to investigate macroscopic spray-combustion parameters by validating Spray-A conditions of the Engine Combustion Network. The present study concerns the spray-combustion characteristics of the ABE mixture (volume ratio 3:6:1), blended with n-dodecane at a volumetric ratio of 20% (ABE20), compared to n-dodecane as reference fuel. The macroscopic spray and combustion parameters were investigated, for non-reactive conditions, in pure Nitrogen and for reactive conditions, in 15% oxygen, at ambient pressure (60 bar), ambient density (22.8 kg/m 3 ) and different ambient temperatures (800 K, 850 K and 900 K). The liquid and vapor spray penetrations were investigated by the Diffused Back Illumination (DBI) and Schlieren techniques in non-reactive conditions. In reactive conditions, the lift-off length was measured by OH* chemiluminescence images at 310 nm. The Schlieren technique was also used to verify the choice of detection criterion. The ignition delay results of the two fuels were compared. It was found that the behavior of the two fuels as a function of temperature was similar even if the liquid length of ABE20 was shorter than that of n-dodecane at all ambient temperatures. On the other hand, no real difference in vapor spray penetration between the two fuels was observed. The vaporization properties and the lower autoignition ability of ABE20 led to longer ignition delays and lift-off length. KeywordsSpray and Combustion Characterizations, Acetone-Butanol-Ethanol (ABE), High-Pressure and High-Temperature Conditions. IntroductionDue to the increase in energy demand and the depletion of oil resources during the last few decades, butanol has become an alternative fuel, considered in the transportation sector as a sustainable energy and also a means to reduce greenhouse gases compared to conventional fuel [1], as it can be produced from renewable bioresources in the form of agricultural biomass and waste [2]. Moreover, butanol induces lower fuel consumption as its energy content is higher than ethanol, up to 30%, and its lower water solubility decreases the tendency to microbial-induced corrosion in fuel storage and pipelines during transportation [1]. The higher cetane number (CN) of butanol (CN = 25) compared to ethanol (CN = 8) leads to easier ignition in compression ignition (CI) engines [3]. It is suitable for diesel injection systems thanks to its high level of viscosity like diesel fuel and no water content, unlike ethanol. Finally, researchers have considered butanol as one means to reduce CO, HC, NOx, and Soot emissions [4] and also to improve comb...

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Quantifying liquid mass distribution data in the dense near nozzle area to develop and optimize diesel spray by optical diagnostic is challenging. Optical methods, while providing valuable information, have intrinsic limitations due to the strong scattering of visible light at gas-liquid boundaries. Because of the high density of the droplets near the nozzle, most optical methods are ineffective in this area and prevent the acquisition of reliable quantitative data. X-ray diagnostics offer a solution to this issue, since the main interaction between the fuel and the X-rays is absorption, rather than scattering, thus X-ray technique offers an appealing alternative to optical techniques for studying fuel sprays. Over the last decade, x-ray radiography experiments have demonstrated the ability to perform quantitative measurements in complex sprays. In the present work, an X-ray technique based on X-ray absorption has been conducted to perform measurements in dodecane fuel spray injected from a single-hole nozzle at high injection pressure and high temperature. The working fluid has been doped with DPX 9 containing a Cerium additive, which acts as a contrast agent. The first step of this work was to address the effect of this dopant, which increases the sensitivity of X-ray diagnostics due its strong photon absorption, on the behavior and the physical characteristics of n-dodecane spray. Comparisons of the diffused back illumination images acquired from ndodecane spray with and without DPX 9 under similar operating conditions show several significant differences. The current data show clearly that the liquid penetration length is different when DPX 9 is mixed with dodecane. To address this problem, the dodecane was doped with a several quantities of DPX containing 25% ± 0.5 of Cerium. Experiments show that 1.25% of Ce doesn't affect the behaviour of spray. Radiography and density measurements at ambient pressure and 60 bars are presented. Spray cone angle around 5° is obtained. The obtained data shows that the result is a compromise between the concentration of dopant for which the physical characteristics of the spray do not change and the visualization of the jet by X-ray for this concentration. KeywordsDiesel Spray, Engine, X-ray radiography, high pressure high temperature chamber, dodecane, Cerium, spray diagnostics Introduction New One Shot Engine (NOSE) has been designed to simulate the thermodynamic conditions at High PressureHigh Temperature (HPHT) like an actual common-rail diesel engine to study the diesel spray and combustion. The first objective was to share the experimental results required by Engine Combustion Network (https://ecn.sandia.gov). In a first step, the penetration lengths for the vapor and liquid spray at the non-reactive standard Spray-A condition (900 K, 60 bar, and 22.8 kg/m 3 with pure nitrogen) were achieved from focused shadowgraphy and diffused-back illumination (DBI) [1]. A detailed understanding of the mixing between fuel and air can lead to more efficient combustion. This ...

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