Cornelia Stan

The Impact of the Wheel’s Rim on the Aerodynamics of Passenger Vehicles

The purpose of this Paper is to investigate the amount of aerodynamic energy consumed by the wheels and the impact on the overall drag of a passenger vehicle. The wheel parts (rim, tire and cap) were modeled and aerodynamically analyzed using a finite element Computational Fluid Dynamics (CFD) software. To highlight the wheel’s potential in the overall aerodynamic drag the rim’s useful area is modified by decreasing the porosity in a progressive manner. The CFD simulation results are presented using Iso-Lambda and Iso-Cpi, parameters together with coefficients like total pressure deficit, skin friction and vorticity magnitude. An important conclusion of the study was the fact that by blocking the flow thru the rim, an aerodynamic potential can be achieved. Careful design of wheels may lead to significant reduction in drag and improvements of vehicle drag coefficient. This would generate lower fuel consumption and important CO2 reduction, leading to a more environmentally friendly vehicle. The work will be continued by extending the analysis towards commercial vehicles like heavy trucks that have a significant number of wheels and are more exposed to air flow. Improvements in this area may lead to a significant reduction in fuel consumption. It should be pointed out that CFD is a good method for developing and optimizing solutions but has to be reinforced by physical tests performed on road or in wind tunnels.

Simulink Model to Optimize Cab Suspension

An important feature in designing a truck’s cab is the driver’s comfort. Through cabin architecture it is intended to optimize its behaviour in all modes of operation of the vehicle.

Comparative Study on the Regeneration of Used Motor Oil

Waste oil is a source of global pollution, both in terms of the amount generated and the environmental toxicity. The used motor oils are contaminated by contaminants and impurities resulted from undesirable oxidation processes: sediment, water, metallic particles and degraded additives.

On the Simulation of Powered Axles Stick-Slip

The use of high power railway vehicles requires enhanced control of wheel-rail adherence. When setting the train in motion, driving axles can exhibit torsional vibrations resulting in poor adherence and even axle damage. A significant number of railway authorities safety warnings and accident reports were issued related to the above phenomena. Adhesion saturation and negative slope are the characteristics which lead to self-sustained axial vibration. The aim of the present work is to prove the appropriateness of non-smooth models in the study of the axle torsional stick-slip vibrations which may occur when traction vehicles are set into motion. The model is simple, observes the main friction characteristics and provides the basis for efficient dynamics simulation. An experimental setup comprising a reduced scale wheel set is analyzed in order to validate the model proposed. The friction parameters are then identified using the proposed force-creepage relationship. Validation and verification is further carried out in frequency domain using both steady state and transient manoeuvres. Specific phenomena like discontinuities in the time-history friction force values occur. Validation and verification is carried out in frequency domain using both steady state and transient manoeuvres. From the comparison between the numerical and experimental results, it can be concluded that the setup is modeled accurately. Related problems may be solved using the present method, as it is pointed out in the article.

The Influence of the Chassis’ Parameters on the Truck Vibrations Transmissibility

Abstract. A modal analysis of truck system was performed. Eigen frequencies and eigenmodes are described. In order to validate the model, the engine was tested with various excitations. Acceleration responses were measured and frequency spectral analyses were performed. The transmissibility was calculated as a ratio of the effective accelerations measured at M, R, Cs, Cd points on the truck structure. The eigenfrequencies of the truck structure are sensitive to the numerical parameters of the model. The influence of the thickness of chassis frame and of the geometry’s cross member on the vibrational behavior of the chassis and on the vibration transmissibility from the engine to the cab truck were studied.