1,721,062 research outputs found
Numerical Evaluation of a New Strategy of Emissions Reduction by Urea Direct Injection for Heavy Duty Diesel Engines
Full text linkThe effect of ammoniac deoxidizing agent (Urea) on the reduction of NOx produced in the Diesel engine was investigated numerically. Urea dissolved in water was directly injected into the engine cylinder during the expansion stroke. The NOx deoxidizing process was described using a simplified chemical kinetic model coupled with the comprehensive kinetics of Diesel oil surrogate combustion. If the technology of DWI (Direct Water Injection) with the later injection timing was used, the deoxidizing reactants could be delivered in a controlled amount directly into the flame plume zones, where NOx formed. Numerical simulations for the Isotta Fraschini DI Diesel engine were carried out using the KIVA-3V code, modified to account for the “co-fuel” injection and reaction with combustion products. The results showed that the amount of NOx could be substantially reduced up to 80% with the injection timing and the fraction of Urea in the solution optimized
Metallic Fuel Co-Generative Plant
No full textThe patent deals with an innovative power co-generation plant based on the combustion of metallic powders in water
An integrated approach to energy recovery from biomass and waste: Anaerobic digestion-gasification-water treatment
No full textThe paper investigates the performance of an integrated system for the energy recovery from biomass and waste based on anaerobic digestion, gasification and water treatment.
In the proposed system, the organic fraction of waste of the digestible biomass is fed into an anaerobic digester, while a part of the combustible fraction of the Municipal Solid Waste is gasified. Thus, the obtained bio-gas and syngas are used as a fuel for running a cogeneration system based on an internal combustion engine to produce electric and thermal power. The waste water produced by the integrated plant is recovered by means of both forward and inverse osmosis.
The different processes as well as the main components of the system are modelled by means of a lumped and distributed parameter approach and the main outputs of the integrated plant such as the electric and thermal power and the amount of purified water are calculated.
Finally, the implementation of the proposed system is evaluated for urban areas with different number of inhabitants and the relating performance is estimated in terms of the main outputs of the system
An Innovative Approach to Kinematic Analysis of Multibody Hydraulic Actuation Systems
No full textThe paper focuses on the development of an innovative methodology for the direct measurement of the main kinematic variables in multi-body hydraulic actuation systems.
The analysis investigates how the motion capture technique has been applied to the experimental determination of position, velocity and acceleration of hydraulically controlled actuation systems for off-highway machineries.
A number of earth-moving machines has been taken into account, in particular a mini-excavator articulated harm has been equipped with both a standard mechanical system for position and acceleration measurement (including different accelerometers, linear and angular transducers), and a set of IR markers for motion capture application.
First, the hydraulically controlled boom-arm-bucket system has been operated using a control routine reproducing a reference operating condition, in order to define the accuracy of the motion capture system in detecting the kinematic quantities’ variations.
At the same time, the hydraulic variables have been also acquired to monitor the behavior during the machine working routine. Thus, the results obtained by the different experimental techniques have been compared, in order to state the reliability of the motion capture technique to predict the fast dynamics of pressure variations through the accurate measurement of mechanical devices’ oscillation.
Finally, the paper reports the main results obtained using the data from the motion capture characterization of the dynamic performance of the mini-excavator, with particular attention devoted to the dynamic analysis through lumped and distributed parameter numerical co-simulation
Numerical Analysis of Swirl Control Strategies in a Four Valve HSDI Diesel Engine
No full textRecent four valve HSDI Diesel engines are able to controlthe swirl intensity, in order to enhance the in-cylinder flowfield at partial load without decreasing breathing capabilities atfull load.Making reference to a current production engine, thepurpose of this paper is to investigate the influence of portdesign and flow-control strategies on both engine permeabilityand in-cylinder flow field.Using previously validated models, 3-D CFD simulationsof the intake and compression strokes are performed in orderto predict the in-cylinder flow patterns originated by thedifferent configurations.The comparison between the two configurations in termsof airflow at full load indicates that Geometry 2 can trap3.03% more air than Geometry 1, while the swirl intensity atIVC is reduced (-30%).The closure of one intake valve (the left one) is veryeffective to enhance the swirl intensity at partial load: theSwirl Ratio at IVC passes from 0.7 to 2.6 for Geometry 1,while for Geometry 2 it varies from 0.4 to 2.9
Proceedings of the 7th FPNI PhD Symposium on Fluid Power
No full textAll Young Researchers and PhD Students coming from all over the world interested in Fluid Power have been invited to present the results and the directions of their scientific activities, and to establish new contacts for a broader R&D cooperation in fluid power technology and related fields.This Proceedings collect about 50 works from about 200 Authors, coming from more than 15 countries, and they highlight the academic results and the industrial applications shown during the 11 Technical Sessions held during the three days of Symposium
Experimental Investigation of an Innovative High-Speed External Gear Pump Prototype for Advanced Electro-Hydraulic Actuated Automotive Transmissions
No full textIn this paper the main performance parameters of an innovative high-speed external gear pump have been measured and analyzed for verifying its potential use as a reliable and efficient power unit for advanced electro-hydraulic actuated, automotive transmissions. More in detail, in order to deal with extremely challenging operating conditions, mainly in terms of rotational speed and delivery pressure, this volumetric machine is equipped with both two suction and delivery ports.
Firstly, the most important hydraulic and mechanical performance parameters have been acquired and evaluated, over a wide range of rotational speeds, spanning between 500 and 7000 rpm, and for two different operating temperatures, respectively equal to 40 and 60 °C.
With the aim to demonstrate the consistency of the implemented experimental procedure, two external gear pump prototypes, with the same design geometrical features, have been tested and compared, also with equivalent measurements provided by the pump manufacturer.
All the experimental tests have been completed with the help of a custom-tailored test bench, equipped with a double Cardan joint and an overdrive, specifically designed for running the pump at high rotational speed and applying a delivery pressure of about 45 bar, very near to a typical actuation value of a modern high-performance automotive transmission.
Finally, an interesting hydraulic layout, where a fraction of the overall volumetric flow rate delivered by the pump is recirculated through the secondary suction port, has been tested and compared with the standard setup where both the suction ports are directly connected to an atmospheric pressure tank. The main performance parameters measured for the two cases are very similar and, thus, the recirculating configuration can be considered as a very promising design solution for the entire actuation system.
At the end of this thorough experimental study, it is possible to conclude that the high-speed external gear pump prototypes tested and analyzed can be considered a reliable and effective alternative hydraulic power unit for advanced high-performance electro-hydraulic actuated automotive transmissions.In this paper the main performance parameters of an innovative high-speed external gear pump have been measured and analyzed for verifying its potential use as a reliable and efficient power unit for advanced electro-hydraulic actuated, automotive transmissions. More in detail, in order to deal with extremely challenging operating conditions, mainly in terms of rotational speed and delivery pressure, this volumetric machine is equipped with both two suction and delivery ports. Firstly, the most important hydraulic and mechanical performance parameters have been acquired and evaluated, over a wide range of rotational speeds, spanning between 500 and 7000 rpm, and for two different operating temperatures, respectively equal to 40 and 60 °C. With the aim to demonstrate the consistency of the implemented experimental procedure, two external gear pump prototypes, with the same design geometrical features, have been tested and compared, also with equivalent measurements provided by the pump manufacturer. All the experimental tests have been completed with the help of a custom-tailored test bench, equipped with a double Cardan joint and an overdrive, specifically designed for running the pump at high rotational speed and applying a delivery pressure of about 45 bar, very near to a typical actuation value of a modern high-performance automotive transmission. Finally, an interesting hydraulic layout, where a fraction of the overall volumetric flow rate delivered by the pump is recirculated through the secondary suction port, has been tested and compared with the standard setup where both the suction ports are directly connected to an atmospheric pressure tank. The main performance parameters measured for the two cases are very similar and, thus, the recirculating configuration can be considered as a very promising design solution for the entire actuation system. At the end of this thorough experimental study, it is possible to conclude that the high-speed external gear pump prototypes tested and analyzed can be considered a reliable and effective alternative hydraulic power unit for advanced high-performance electro-hydraulic actuated automotive transmissions
CFD MODELING OF DIESEL OIL AND DME PERFORMANCE IN A TWO-STROKE FREE PISTON ENGINE
No full textThis paper presents the CFD KIVA3V, rel. 2 model and numericalresults of combustion process simulations in a two-stroke, uniflowscavenging dual free piston engine, FPE, designed for electricity generation.Two fuels, diesel oil and dimethyl ether (DME), were studiedin order to achieve HCCI-like combustion. Limited size reactionmechanisms were constructed and used in the modeling. The dieseloil surrogate mechanism consisting of a mixture of n-heptane andtoluene includes 70 species participating in 305 reactions, whereasthe mechanism for DME consists of 43 species participating in 211reactions. The combustion development has been simulated in aFPE prototype geometry. It is illustrated that by varying the directinjection timings, a comparably efficient, low-emission operationhas been achieved for both fuels. Specific difficulties when usingslowly vaporizing diesel oil and rapidly vaporizing DME are outlined
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