Experimental and numerical investigation of split injections at low load in an hddi diesel engine equipped with a piezo injector

In order to investigate the effects of split injection on emission formation and engine performance,experiments was carried out using a heavy duty single cylinder Diesel engine. Split injections with varied dwell Time and start of injection were investigated and compared with single injection cases. In order to isolate the effect of the parameters selected to investigate,other variables were kept constant. In this investigation no EGR was used. The engine was equipped with a common rail injection system with a piezoelectric injector. To interpret the observed phenomena,engine CFD simulations using the KIVA-3V code were also made. The results show that a reduction in NOx emissions and brake specific fuel consumption was achieved for short dwell times whereas they were increased when the dwell time was prolonged. No EGR was used so the soot levels were already very low in the cases of sinGle injections. The results indicated,however,no increase in soot as a result of splitting the injection in two parts. Both HC and CO emissions were found to increase with split injections.In order to investigate the effects of split injection on emission formation and engine performance, experiments were carried out using a heavy duty single cylinder diesel engine. Split injections with varied dwell time and start of injection were investigated and compared with single injection cases. In order to isolate the effect of the selected parameters, other variables were kept constant. In this investigation no EGR was used. The engine was equipped with a common rail injection system with a piezo-electric injector. To interpret the observed phenomena, engine CFD simulations using the KIVA-3V code were also made. The results show that reductions in NOx emissions and brake specific fuel consumption were achieved for short dwell times whereas they both were increased when the dwell time was prolonged. No EGR was used so the soot levels were already very low in the cases of single injections. The results indicated, however, no increase in soot as a result of splitting the injection in two parts. Both HC and CO emissions were found to increase with split injections. Copyright © 2006 SAE International

Combustion analysis of a light duty diesel engine using oxygen-enriched and humidified combustion air

The present work presents the results of 3D CFD combustion simulations of a current production 4-cylinder turbocharged Diesel engine using oxygen-enriched and humidified combustion air. Enriched Air (EA) is supposed to be produced by desorption from water, exploiting the different Henry constants of N2 and O2. Simulation results show that EA permits to increase the engine thermal efficiency (up to 10%) and drastically reduces soot emissions but increases in-cylinder peak pressure and NOx emissions. Combustion air humidification helps to reduce NOx increment, without losing the advantage in terms of thermal efficiency and in soot reduction, even if NOx emissions cannot be reported to the base case values

Case studies of automation in services

A full understanding of the technological complexity underlying robotics and automation is still lacking, most of all when focusing on the impacts on work in services. By means of a qualitative analysis based on over 50 interviews to HR managers, IT technicians, workers and trade union delegates, this work provides evidence on the main changes occurring at shopfloor level in selected Italian companies having adopted technological artefacts potentially affecting labour tasks by automating processes. The analysis of interviews complemented with visits to the companies and desk research on business documents highlights that so far labour displacement due to the adoption of automation technologies is not yet in place, while tasks and organizational reconfiguration appear more widespread. Major heterogeneity applies across plants due to the final product/service produced, the techno-organizational capabilities of the firm and the type of strategic orientation versus technological adoption. These elements also affect drivers and barriers to technological adoption. Overall, the analysis confirms the complexity in automating presumably low-value-added phases: human labour remains crucial in conducting activities that require flexibility, adaptability and reconfiguration of physical tasks. Further, human agency and worker representation, in particular the role of trade unions, are almost disregarded and not considered by the firms when deciding to introduce a new technology

Case Studies of Automation in Services. A workplace analysis of logistics, cleaning and health sectors in Italy

A full understanding of the technological complexity underlying robotics and automation is still lacking, most of all when focusing on the impacts on work in services. By means of a qualitative analysis relying on the administration of more than 50 interviews to HR managers, IT technicians, workers and trade union delegates, this work provides evidence on the main changes occurring at shopfloor level in selected Italian companies having adopted technological artefacts potentially affecting labour tasks by automating processes. The analysis of interviews complemented with visits to the companies and desk research on business documents highlights that so far labour displacement due to the adoption of automation technologies is not yet in place, while tasks and organizational reconfiguration appear more widespread. Major heterogeneity applies across plants due to the final product/service produced, the techno-organizational capabilities of the firm and the type of strategic orientation versus technological adoption. These elements also affect drivers and barriers to technological adoption. Overall, the analysis confirms the complexity in automating presumably low-valueadded phases: human labour remains crucial in conducting activities that require flexibility, adaptability and reconfiguration of physical tasks. Further, human agency and worker representation, in particular the role of trade unions, are almost disregarded and not considered by the firms when deciding to introduce a new technology

Resistance of Trichoplusia ni to Bacillus thuringiensis Toxin Cry1Ac Is Independent of Alteration of the Cadherin-Like Receptor for Cry Toxins

Alteration of binding sites for Bacillus thuringiensis (Bt) toxins in insect midgut is the major mechanism of high-level resistance to Bt toxins in insects. The midgut cadherin is known to be a major binding protein for Bt Cry1A toxins and linkage of Bt-resistance to cadherin gene mutations has been identified in lepidopterans. The resistance to Bt toxin Cry1Ac evolved in greenhouse populations of Trichoplusia ni has been identified to be associated with the down-regulation of an aminopeptidase N (APN1) gene by a trans-regulatory mechanism and the resistance gene has been mapped to the locus of an ABC transporter (ABCC2) gene. However, whether cadherin is also involved with Cry1Ac-resistance in T. ni requires to be understood. Here we report that the Cry1Ac-resistance in T. ni is independent of alteration of the cadherin. The T. ni cadherin cDNA was cloned and the cadherin sequence showed characteristic features known to cadherins from Lepidoptera. Various T. ni cadherin gene alleles were identified and genetic linkage analysis of the cadherin alleles with Cry1Ac-resistance showed no association of the cadherin gene with the Cry1Ac-resistance in T. ni. Analysis of cadherin transcripts showed no quantitative difference between the susceptible and Cry1Ac-resistant T. ni larvae. Quantitative proteomic analysis of midgut BBMV proteins by iTRAQ-2D-LC-MS/MS determined that there was no quantitative difference in cadherin content between the susceptible and the resistant larvae and the cadherin only accounted for 0.0014% (mol%) of the midgut BBMV proteins, which is 1/300 of APN1 in molar ratio. The cadherin from both the susceptible and resistant larvae showed as a 200-kDa Cry1Ac-binding protein by toxin overlay binding analysis, and nano-LC-MS/MS analysis of the 200-kDa cadherin determined that there is no quantitative difference between the susceptible and resistant larvae. Results from this study indicate that the Cry1Ac-resistance in T. ni is independent of cadherin alteration

The evaluation of masonry shear strength by means of different experimental techniques: A comparison between full-scale and laboratory tests

Seismic vulnerability of masonry structures was recently confirmed, if necessary, by last earthquakes who stroke in Italy some years ago. As a consequence, great efforts are actually devoted to the assessment of the masonry built heritage; in this framework, the definition of shear capacity of masonry is of paramount importance, even though the available experimental techniques are often too invasive (full destructive tests) or provide for really scattered results (non-destructive tests). Present work analyses the possible correlation among masonry shear mechanical parameters obtained from different types of destructive and moderately destructive tests. To this purpose, an experimental campaign on full-scale masonry samples built using hydraulic-lime based mortar and clay bricks, was carried out and described in this paper. At the same time, a number of laboratory tests on smaller specimens and cores made of the same masonry were also considered. Diagonal compression tests were carried out on double-leaf masonry panels while direct shear tests were conducted on single-leaf masonry specimens and triplets; finally, cores (cored from panels) were subjected to splitting test with different mortar layer inclinations. Comparison of first results suggested the quality of correlation between different experimental tests, when both shear sliding and diagonal tensile failure modes are considered

Optimization of a supercharged single cylinder engine for a formula SAE racing car

The paper reviews the development and optimization of a SI high performance engine, to be used in Formula SAE/Student competitions. The base engine is a single cylinder Yamaha 660cc motorcycle unit, rated at about 48 HP at 6000rpm. Besides the reduction of engine capacity to 600cc and the mounting of the required restrictor, mechanical supercharging has been adopted in order to boost performance. The fluid-dynamic optimization of the engine system has been performed by means of 1D-CFD simulation, coupled to a single-objective genetic algorithm, developed by the authors. The optimization results have been compared to the ones obtained by a well known commercial optimization software, finding a good agreement. Experiments at the brake dynamometer have been carried out, in order to support engine modeling and to demonstrate the reliability of the optimization process. Copyright © 2009 SAE International

Application to micro-cogeneration of an innovative dual fuel compression ignition engine running on biogas

Renewable sources and enhancement of energy conversion efficiency are the main paths chosen by the European Community to stop climate changes and environmental degradation, and to enable a sustainable growth. For this purpose, the construction of a new and more dynamic electricity distribution network is mandatory. This “smart grid” should also include small and medium-size companies, able to program the generation and use of energy from renewable sources (the so-called "prosumers"). In this frame, micro-cogeneration (rated electric power up to 50 kW) is one of the most promising techniques. In this work, the application to micro-cogeneration of an innovative Compression Ignition internal combustion engine, operated in Dual Fuel mode is proposed. Thanks to the specific combustion system (Reactivity Controlled Compression Ignition, RCCI: a lean homogenous mixture of air and biomethane or biogas is ignited by the injection of a small amount of Diesel fuel), brake thermal efficiency can be increased at all operating conditions, compared to a conventional Spark Ignition engine running on biomethane or biogas. The ensuing reduction of CO2 emissions is higher than 20%. Furthermore, the proposed engine can tolerate larger variations in the composition of the biogas, without a significant drop of thermal efficiency. Finally, in case of emergency, it is able to run on Diesel fuel only. The use of the engine is particularly suitable for a company operating in the agricultural field, such as a mid-size farm, that is able to produce biogas for its self-consumption. Therefore, a representative study case is selected, and the corresponding electrical and thermal energy needs are analysed throughout a typical year. The energetic analysis leads to the identification of the most suitable engine size and calibration settings, in order to reduce the purchase of electricity and natural gas, maximizing the use of the company's own renewable sources (biogas or biomethane). The final goal of the optimization process is to create a virtuous system, that can reduce the environmental impact and make the company almost independent from the energetic point of view