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The Injection Rate Shaping consists in a novel injection strategy to control air-fuel mixing quality via a suitable variation of injection timing that affects the injection rate profile. This strategy has already provided to be useful to increase combustion efficiency and reduce pollutant emissions in the modern compression ignition engines fed with fossil Diesel fuel. But nowadays, the ever more rigorous emission targets are enhancing a search for alternative fuels and/or new blends to replace conventional ones, leading, in turn, a change in the air-fuel mixture formation. In this work, a 1D model of spray injection aims to investigate the combined effects of both Injection Rate Shaping and alternative fuels on the air-fuel mixture formation in a compression ignition engine. In a first step, a ready-made model for conventional injection strategies has been set up for the Injection Rate Shaping.

The paper discusses the concept, specification and overall performance of a small microcogeneration unit of about 1,5 kW of electric power and about 4,5 kW of thermal power, suitable for domestic applications, designed at Istituto Motori CNR of Italy. This unit has been conceived specifically as a energy conversion system for houses, having in durability, electric and thermal efficiency the most important goals to be achieved. The paper starts by defining the state of art of small power microcogeneration units and then the ratio which leaded to the adoption of a single cylinder internal combustion engine derived from a motorcycle unit, in order to produce the above mentioned electric and thermal power. This is followed by an explanation of the main design characteristics of the system, with a discussion over the modified elements, made to enhance electric efficiency, emissions and durability and reduce, at the same time, cost coming from new design and manufacture.

During gasoline direct injection (GDI) in spark ignition engines, droplets may hit piston or liner surfaces and be rebounded or deposit in the liquid phase as wallfilm. This may determine slower secondary atomization and local enrichments of the mixture, hence be the reason of increased unburned hydrocarbons and particulate matter emissions at the exhaust. Complex phenomena indeed characterize the in-cylinder turbulent multi-phase system, where heat transfer involves the gaseous mixture (made of air and gasoline vapor), the liquid phase (droplets not yet evaporated and wallfilm) and the solid walls. A reliable 3D CFD modelling of the in-cylinder processes, therefore, necessarily requires also the correct simulation of the cooling effect due to the subtraction of the latent heat of vaporization of gasoline needed for secondary evaporation in the zone where droplets hit the wall. The related conductive heat transfer within the solid is to be taken into account.

This paper reports 1D and 3D CFD analyses aiming to improve the gas-dynamic noise emission of a downsized turbocharged VVA engine through the re-design of the intake air-box device, consisting in the introduction of external or internal resonators. Nowadays, modern spark-ignition (SI) engines show more and more complex architectures that, while improving the brake specific fuel consumption (BSFC), may be responsible for the increased noise radiation at the engine intake mouth. In particular VVA systems allow for the actuation of advanced valve strategies that provide a reduction in the BSFC at part load operations thanks to the intake line de-throttling. In these conditions, due to a less effective attenuation of the pressure waves that travel along the intake system, VVA engines produce higher gas-dynamic noise levels.

This document will address techniques or methods that have been used within the industry to address the problem of engine stability margin accounting when combinations of distortion types exist in an aircraft installation. Its focus is combining temperature, planar wave, and swirl distortion with time-variant spatial total pressure distortion. Example methodologies will be presented along with example cases where co-existing distortions have been evaluated. It will also address the areas where the industries' knowledge base is lacking (experimental data or computational methods) and the future work that is needed for methodology development in these areas. This document is viewed to be updated every five years as more information (data either experimentally or analytically) becomes available.

In this paper, the results of an extensive experimental analysis regarding a twin-cylinder spark-ignition turbocharged engine are employed to build up an advanced 1D model, which includes the effects of cycle-by-cycle variations (CCVs) on the combustion process. Objective of the activity is to numerically estimate the CCV impact primarily on fuel consumption and knock behavior. To this aim, the engine is experimentally characterized in terms of average performance parameters and CCVs at high and low load operation. In particular, both a spark advance and an air-to-fuel ratio (α) sweep are actuated. Acquired pressure signals are processed to estimate the rate of heat release and the main combustion events. Moreover, the Coefficient of Variation of IMEP (CoVIMEP) and of in-cylinder peak pressure (CoVpmax) are evaluated to quantify the cyclic dispersion and identify its dependency on peak pressure position.

The development of future more-and full-electric aircraft concepts has significantly impacted aircraft electric power system (EPS) design. Finalizing the EPS architectures involves extensive modeling and simulation activities to ensure the required characteristics of the entire EPS prior to the physical implementation. Hence, the development of accurate, effective and computational time-saving simulation models is of great importance. Correspondingly, there is a need to establish an EPS-specific modeling and simulations common framework to ensure effective and accurate solutions to the problems addressed. The document continues a series of AE-7M documents specific for aircraft electrical systems aiming to establish such a framework (the series has started with AIR 6326 "Aircraft Electrical Power Systems. Modeling and Simulation. Definitions" issued in August, 2015).

In the recent years, the interest in heavy-duty engines fueled with Compressed Natural Gas (CNG) is increasing due to the necessity to comply with the stringent CO2 limitation imposed by national and international regulations. Indeed, the reduced number of carbon atoms of the NG molecule allows to reduce the CO2 emissions compared to a conventional fuel. The possibility to produce synthetic methane from renewable energy sources, or bio-methane from agricultural biomass and/or animal waste, contributes to support the switch from conventional liquid fuels to CNG. To drive the engine development and reduce the time-to-market, the employment of numerical analysis is mandatory. This requires a continuous improvement of the simulation models toward real predictive analyses able to reduce the experimental R&D efforts. In this framework, 1D numerical codes are fundamental tools for system design, energy management optimization, and so on.

As a simulation of road driving, wind tunnel testing of full-size vehicles produces certain errors in the aerodynamic forces, aerodynamic moments, and surface pressures. The magnitude of these errors, in general, depends on the following: a.) Flow quality, b.) Determination of the reference dynamic pressure, c.) Wind tunnel floor boundary layer, d.) Test section geometry and position of the car within that geometry, e.) Shape of the vehicle, f.) Blockage ratio: The ratio of the cross-sectional area of the vehicle to the cross-sectional area of the wind tunnel nozzle, g.) Wheel rotation, and h.) Internal flow in the model. The SAE Standards Committee, Open Throat Wind Tunnel Adjustments, had as a goal to document the knowledge of the influence of model interference on wind tunnel test results for automotive open jet wind tunnels. This document contains the following information related to this subject: a.) Design data of open throat wind tunnels, b.)

Aeroengine Hazard Zone document will standardize the major aspects of processes that may be used for the determination of hazards to aerospace personnel when performing duties on turbojet, turbofan, turboprop and auxiliary power units installed on aircraft. It includes discussions of basic definitions, analytical and methods to describe the hazard zones for a given propulsion system installed on various aircraft. Standardization of definitions of sources of hazards, tools, presentation of hazard zones would benefit airplane, engine, airline customers and airport planners.

The recommendations of this SAE Aerospace Recommended Practice (ARP) for aircraft compartment automatic temperature control systems are primarily intended to be applicable to occupied or unoccupied compartments of civil and military aircraft.

This SAE Aerospace Recommended Practice (ARP) provides recommended definitions for terms commonly used in aircraft inflight icing system design and analysis, research, and operations. Some general thermodynamic terms are included that are frequently used in icing analysis, but this document is not meant to be an inclusive list of such terms.

This proposed revision of the Aerospace Recommended Practice (ARP6973) will provide minor edits to the existing document, plus an alternative third method for measuring the aircraft noise level reduction of building façades that is currently being validated. Airports and their consultants will be able to use any of the three methods presented in this revised ARP to determine the eligibility of structures exposed to aircraft noise to participate in an FAA-funded Airport Noise Mitigation Project, to determine the treatments required to meet project objectives, and to verify that such objectives are satisfied.

This SAE Aerospace Design Standard defines a coupling, which is installed in a high pressure (1850 to 2000 psig) oxygen system of a civil transport aircraft for the purpose of mating to ground oxygen replenishment facilities. Dimensions developed from AND10089, Detail Specification Sheet for Fitting End, Design Standard, For Cone Connection.

This SAE Aerospace Standard (AS) provides a performance station designation system for aircraft propulsion systems and their derivatives. The station numbering conventions presented herein are for use in all communications concerning propulsion system performance such as computer programs, data reduction, design activities, and published documents. They are intended to facilitate calculations by the program user without unduly restricting the method of calculation used by the program supplier. The contents of this document were previously a subset of AS755E. Due to the growing complexity of station numbering schemes and an industry desire to expand nomenclature descriptions, a decision was made to separate the “station numbering” and “nomenclature” contents of AS755 into two separate documents. AS755 will continue to maintain standards for station numbering. SAE Aerospace Standard AS6502 will maintain standards for classical nomenclature moving forward.

This document is a guideline for the design and operation of Aviation Aircraft Refueling Vehicles and for the materials, components, and systems used thereon. The criteria set forth herein are the minimum recommendations for all types of aircraft refueling vehicles, including tanker vehicles, hydrant service vehicles, towable hydrant carts, fixed refueling cabinets, and any other type of aircraft refueling vehicles used at airports for aircraft refueling operations with nominal operating fuel pressures and flow rates as specified within this document.

This SAE Aerospace Recommended Practice (ARP) documents a common understanding of terms, compliance issues, and design criteria to facilitate certification of seat installations specific to Part 25 aircraft. This ARP provides general guidance for seats to be installed in Part 23 aircraft and Parts 27 and 29 rotorcraft and does not specify specific designs or design methods for such certification.

This paper reports the study of the effects of alternative diesel fuel and the impact for the air-fuel mixture preparation. The injection process characterization has been carried out in a non-evaporative high-density environment in order to measure the fuel injection rate and the spatial and temporal distribution of the fuel. The injection and vaporization processes have been characterized in an optically accessible single cylinder Common Rail diesel engine representing evaporative conditions similar to the real engine. The tests have been performed by means of a Bosch second generation common rail solenoid-driven fuel injection system with a 7-holes nozzle, flow number 440 cc/30s @100bar, 148deg cone opening angle (minisac type). Double injection strategy (pilot+main) has been implemented on the ECUs corresponding to operative running conditions of the commercial EURO 5 diesel engine.

The present paper describes some results of a cooperative research project between GM Powertrain Europe and Istituto Motori of CNR aimed at studying the impact of FAME and GTL fuel blends on the performance, emissions and fuel consumption of the latest-generation automotive diesel engines. The investigation was carried out on the newly released GM 2.0L 4-cylinder “torque-controlled” Euro 5 diesel engine for PC application and followed previous tests on its Euro 4 version, in order to track the interaction between the alternative fuels and the diesel engine, as the technology evolves. Various blends of first generation biodiesels (RME, SME) and GTL with a reference diesel fuel were tested, notably B20, B50 and B100. The tests were done in a wide range of engine operation points for the complete characterization of the biodiesels performance in the NEDC cycle, as well as in full load conditions.

In the present paper the status of development of diesel combustion and pollutants formation modelling at Diesel Engines and Fuels Research Division of Istituto Motori is pointed out. The main features and performances of the model are discussed comparing the numerical results with some experimental data. For the experiments a single cylinder direct injection diesel engine was used. In the head of the engine two small quartz windows have been mounted, in order to obtain pictures of the injection and combustion processes by high speed cinematography, and to apply the two colour technique for soot temperature and soot loading measurements. The soot loading was measured by the two colour technique and the a priori and the experimental uncertainties of the measurement technique were carefully evaluated. In addition, the engine may be also equipped with a second head, in which a fast acting valve allows the direct sampling of the combustion products.