Key Engineering Materials Vol. 597

Abstract: The focus of this paper is on CAPP for parts manufacture in systems of definite process capabilities, involving the use of multi-axis machining centers for parts shaping and grinding machines for finishing. It presents in particular a decision making scheme for setup determination as a part of generative process planning. The planning procedure consists of two stages. The first stage is associated with generic setup determination applying tool accessibility analysis to machined features and reasoning based on geometrical product specification (GPS). The second stage involves machine specific setup planning considering the availability and capability of machines on a shop floor through setup merging. The impact of dimensional and geometric tolerance as well as the surface roughness of relatively complex mechanical element on the generated process plan with several setups was presented. The relevant reasoning mechanism within a decision making scheme on generated process alternatives is shown based on a numeric case.

Abstract: Run flat properties are required for tires intended for special applications like military or rescue vehicles. Run-Flat inserts make possible to drive a car or truck, with certain restrictions, also when inflation pressure is very low or non-existing (after tire damage). Rolling resistance of tires rolling on the inserts increases considerably in relation to the rolling resistance of properly inflated tires. This paper presents results of rolling resistance measurements for such conditions.

Abstract: One of the types of hydrogen degradation of steel welded joints is cold cracking. The direct cause of the formation of cold cracks is simultaneous presence of hydrogen, residual stresses and brittle structure. The way of preventing the occurring of degradation is to eliminate at least one of these factors. Practice has shown that the best solution is to control the amount of hydrogen in deposited metal. In this paper an experimental evaluation of the effect of the welding parameters on the content of diffusible hydrogen in deposited metal obtained from rutile flux cored wire grade H10 was carried out. The state of the art of considered issues was described and results of preliminary investigations were presented. Five factors were considered: the flow rate of shielding gas, the welding current, the arc voltage, the welding speed and the electrode extension. All factors were optimized using a Plackett-Burman design to get the most relevant variables. The level of diffusible hydrogen was determined by a glycerin test. The results of the experiment indicate that appropriate choice of welding parameters may significantly reduce diffusible hydrogen content in deposited metal.

Abstract: The article presents an analysis of the car engine loads. The aim of the analysis was to determine the parameters of the brake / electric motor on an engine test bad. Analysis of loads on the driving tests concerned on chassis dynamo to simulate them on an engine dynamometer. To check the range of dynamometer shaft angular acceleration inertial mass of a car was reduced on the crankshaft axis. The calculations of maximum shaft acceleration were performed. Also the whole car acceleration when pulling away from the place was calculated. Calculations were verified by experiment on road. They both gave a good agreement.

Abstract: Operating fuel consumption increases significantly when the vehicle stops frequently while driving or when the engine is idling during braking. In such cases, the internal combustion engine consumes the fuel but the mechanical energy is not used by the drive system. The amount of fuel that is consumed in this time by the engine can potentially be saved if the car is equipped with a Stop-Start system. Start-Stop system automatically shuts down and restarts the internal combustion engine due to strategy used by controller reducing this way toxic compounds emissions in exhaust gasses and the fuel consumption, which is directly connected to carbon dioxide (CO₂) emissions. The paper presents an analysis of the potential reduction in CO₂ emissions for selected vehicles with Start-Stop system during operation in selected urban agglomeration using different strategies to control this system. The study was carried out using numerical models of propulsion systems. The results were compared with the statistical data derived from regular use of vehicles equipped with such a system.

Abstract: Tire rolling resistance is one of the most important resistive forces acting on road vehicles. It depends on tire and surface characteristics as well as vehicle operating parameters. This paper deals with the influence of road surface texture on rolling resistance of passenger car tires. Results of road measurements performed on variety of road surfaces are presented.

Abstract: Most important features of the child seat were presented. There was made analysis of selected dynamic loads acting on mannequins heads during a collision. Comparison of loads acting on the kid in a child seat and the other passengers in a car is presented. In analysis of the results particular attention has been paid on the children's secure in a car. The phenomena of collision child's occipital bone with seat backrest was described. There were presented results of dynamic test of chosen kind of materials, which were expected for having good energy absorbing characteristic. Selected courses of dynamic forces, values of peak forces and time of dynamic forces acting for tested materials were shown. The tests were made on dynamic droptower impact system Instron CEAST 9310.