Papers by Keyword: Piston

Abstract: Hydroxyapatite is naturally found in bone tissue. Tissue engineering often utilizes synthetic hydroxyapatite biocomposite for bone alloplastic grafting. The bone graft shape and size accuracy can be realized using three dimensions (3D) printing technology. The most important part of the 3D printer is an extruder producing printable filament of the material. This work presents a design of the extruder employed to create a gelatine filament. The gelatin will be used as the matrix of a hydroxyapatite biocomposite in the future. The main components of the extruder are a 10 mL acrylic syringe and a non-captive stepper motor. Three parameters, i.e., extrusion speed, material viscosity, and nozzle size, are examined to find the optimum filament production. The extrusion speed was controlled by programming the frequency step of the motor, and the viscosity was controlled by varying the composition of the aquadest-gelatine mixture. The results showed that the stable operation and the best filament were obtained with a motor speed of 0.17 mm/s, the aquadest-gelatine composition of 10 mL aquadest and 3 grams of gelatine powder, and a nozzle diameter of 0.3 mm.

Abstract: The microstructure and mechanical properties of thixoformed AlSi12Cu2NiMg (AЛ25) aluminium alloy were investigated. Cooling slope method was employed in order to produce non-dendritic billets. Thixoforming process parameters were determined as follows: die temperature of 250 °C, billet temperature of 555 - 560 °C, punch velocity of 7 mm/s. Mechanical properties of automotive piston with ultimate strength of 309 MPa, yield strength of 274 MPa and elongation of 6.8 % in the T6 condition were obtained successfully, implying success of advantages of cooling slope method.

Abstract: In this paper, the microstructure and mechanical properties of thixoformed 1973 (AlZn5.5Mg2.4Cu1.7Zr) wrought aluminium alloy were investigated. A cooling slope was used to produce non-dendritic billets. Thixoforming process parameters were determined as follows: die temperature of 250 °C, feedstock temperature of 600 - 605 °C, punch velocity of 7 mm/s. Mechanical properties of thixoformed with ultimate strength of 461 MPa and elongation of 3,1 % in the T2 condition. The lower properties of the thixoformed material are mainly associated with porosity.

Abstract: Abstract: The combined effect of variable viscosity and thermal conductivity on dissipative flow of oil-based nanofluid over a permeable vertical plate with suction has been studied. The governing partial differential equations have been transformed into a coupled third-order ordinary differential equations using similarity techniques. The resulting third-order ordinary differential equations were then reduced into a system of first-order ordinary differential equations and solved numerically using the fourth-order Runge-Kutta algorithm with a shooting method. The results revealed that both viscosity and thermal conductivities of CuO oil-based nanofluid enhances the intensity of the skin friction coefficient and the rate of heat transfer at the surface of the plate. Furthermore, the thermal boundary layer thickness is weakened by the viscosity of CuO oil-based nanofluid, the Prandtl number, the suction parameter, the permeability of the medium and the thermal Grashof number

Abstract: Pistons are commonly made of a cast aluminum alloy for excellent and lightweight thermal conductivity. Thermal conductivity is the ability of a material to conduct and transfer heat. Aluminum expands when heated and proper clearance must be provided to maintain free piston movement in the cylinder bore. The piston transforms chemical energy of the burned fuel into a mechanical energy. For this reason, the pistons are submitted to a complex combination of thermal stresses and high temperature mechanical cycles. In this study both powder metallurgy (PM) and thixoforming techniques are used to process a metallic matrix composite (MMC) as a promising material for pistons. Aluminum as matrix and copper powder, to enhance thermal conductivity, and glass fiber, which increases Young’s modulus and a lower thermal expansion coefficient, as reinforcement, are obtained for this aim. The optical microscope images showed in this study are a clear example of the distribution of the glass fiber in the matrix. These results can be the basis for new researches to develop and to obtain materials for new advanced materials for pistons.

Abstract: A390 functionally graded material (FGM) pistons were fabricated by centrifugal casting, where the silicon particles were segregated in the head portion of the pistons by appropriate design and their density differences. Centrifugal casting offers casting of cylindrical structures with gradation in its properties. In centrifugally cast A390, a suitable die design can lead to the formation of hard primary Si particles gradually distributed towards the head region producing a particle rich zone, transition zone and matrix rich zone. Microstructure and chemical composition analysis confirms the composition gradation. Hardness and wear test results revealed that the gradation positively helps to improve the desired properties with the presence of in-situ primary silicon reinforcements.

Abstract: Fuel economy improvement has become the most important issue in automobile engine developments nowadays. The measurements of various parameters in the engine parts, such as temperature, strain and gap have become more important due to the development of fuel-saving technologies. The conventional measuring method is difficult to be adapted to the moving parts at high engine speeds due to the durability of the wire in the measurement system. On the other hand, the telemetric system enables the measuring information to be transferred wirelessly. Therefore, we have applied this system to piston temperature measurements that need to be conducted under various operating conditions. The experimental results of the piston temperature measurements at high engine speeds up to 6500[rpm] are shown in this report.

Abstract: This paper addresses a study undertaken to develop spatial numerical models of a piston, a piston pin and a connecting rod with reference to real components of a combustion engine crank system. The numerical studies conducted comprised an analysis of how the mechanical strength of piston pins was influenced depending on the change in their inner shape. For the purposes of calculations, various scenarios of shape modification were proposed for piston pins currently in use, enabling their weight to be reduced.

Abstract: In recent years, the computer software and technology and the rapid development of finite element theory promote the internal combustion engine dynamic analysis process, greatly improving the application of the internal combustion engine complex parts of the finite element analysis of the efficiency of the precision and reliability of.CAE technology in engine design in the field of eventually allow designers to design modern engine with high performance, low emission, low fuel consumption and low noise, light weight and miniaturization.

Abstract: For simplifying the cockamamie measurement process, in this paper, special equipment for measuring non-cylinder pinhole of piston is designed and implemented. First of all, the measuring principle, the hardware structure and the software system are illustrated. In addition, the measurement error is analyzed in detail. Finally, it is proved that the precision of the instrument is as high as that of the foreign advanced instrument.