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

Direito e saúde: a discricionariedade nas ações fiscais da vigilância sanitária de alimentos

A Ciência do Direito orienta-se por princípios os quais constituem a base que rege todas as relações jurídicas existentes. À Vigilância Sanitária e ao Sistema Único de Saúde cabem a responsabilidade pelas ações de fiscalização e inspeção de alimentos, bebidas, águas de consumo, embalagens e matérias-primas alimentares, além dos estabelecimentos industriais e comerciais de alimentos, com o propósito de prevenir riscos à saúde do consumidor. As normas jurídicas sobre alimentos são complexas e abrangentes e, em várias situações, não muito claras, delegando ao agente responsável pela ação fiscal a interpretação do texto legislativo e a aplicabilidade da sanção ou penalidade que melhor couber ao caso. Busca-se neste trabalho, identificar e compreender a utilização dos atos administrativos enquanto normas aplicadas à Vigilância Sanitária, no Sistema Federativo Brasileiro, no desenvolvimento das atividades rotineiras. Conclui-se que a discricionariedade administrativa, permitida nas ações fiscais da Vigilância Sanitária, justifica-se pela ampla variedade e quantidade de problemas a serem equacionados pelos agentes na sua jornada de trabalho, para os quais a lei, por mais abrangente e completa, nem sempre tem respostas, cabendo aos agentes tomar as medidas mais adequadas a cada caso, de acordo com o seu conhecimento técnico-científico e senso comum

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