Purpose – This paper aims to study the effect of piston skirt design parameters on the dynamic characteristics of a piston–cylinder contact. Design/methodology/pproach – This paper focuses on an analysis of the piston dynamic response. The oil-film pressure and the structural deformation were approximated, respectively, by finite difference method and finite element method. Findings – The results show that the design parameters such as clearance, offset and the axial location of piston pin have a great influence on the dynamics of the piston and hence on the piston slap phenomenon and the frictional power loss. Originality/value – All the results mainly focus on the slap noise of the engine and can be used in the piston–liner development at the development of the engine.

No abstract

Biogas is a renewable fuel and an energy source that can be applied in many different settings. It is defined as a combustible gas mixture produced by the anaerobic fermentation of biomass by bacteria and takes several days to form. In fact, the anaerobic digestion is a biological process, so valorizing organic matter, usually fatal, produces a renewable energy source and digestates that can be used as a fertilizer. Indeed, in the absence of oxygen (anaerobic digestion) and protected from light, organic matter is partially degraded by the combined action of several types of micro-organisms, a series of biological reactions leading to the formation of biogas composed of Carbon Dioxide (CO 2 ), Nitrogen N 2 , Hydrogen H 2 , Oxygen O 2 , Water vapor H 2 O, Hydroxide Sulfur H 2 S and the energy recoverable portion Methane CH 4 but very harmful to the environment, or even 22 times more harmful than CO 2 which is a greenhouse gas (GHG). Therefore, Waste-to-energy provides a solution for two problems: waste management and energy generation. This biogas opportunity has appeared as one of the most interesting applications to help many municipalities in different countries to produce clean energy and even to manage wastes. It can be applied on the wastes of the agricultural fields as well as in the farms, in the food industry or simply in the municipal landfills. Numerous biogas installations have been built all over the world. Initially, the main objective was to produce biogas to generate energy, but quickly the environment aspect has appeared as an additional reason to build such facilities. This study covers the sustainable development area in which we will estimate the potential to produce biogas starting from the annual organic wastes data given by the concerning ministries and organizations in Algeria.

Cet article présente un modèle de lubrification mixte en conjonction avec une analyse du mouvement secondaire du piston. Certains paramètres influent ce genre de mouvement tel que l'élasticité de la jupe et la forme de son profil (plat ou bombé). Les résultats montrent que ces paramètres ont une grande influence sur les forces de frottement, et par conséquent, ils ont le potentiel pour optimiser la perte de puissance par frottement du piston.

This work is a study of coupled charges and heat transfers phenomena on a low temperature PEMFC single cell. A one-dimensional steady state model was developed to compute current and temperature distributions in a PEMFC single cell whatever the operating conditions. The work comprises of three parts: Firstly, a litterature survey was conducted to describe the principle of a PEMFC and the fundamental operations. A state of the art of the previous modeling works on the PEMFC was also presented in this part. Secondly, the developed model using the basic relations to describe heat and charges transfer phenomena occurring in the single PEM cell was presented. Finally , a simple simulation tool called FCvb was performed and optimized using Visual Basic Excel and refering to the previous relations in the developed model. To finalize this basic study, a conclusion and perspectives were presented in the last part of this work.