Automotive Science and Engineering
Volume:4 Issue: 3, Summer 2014

The current experimental study is to investigate the effects of process parameters (cutting speed, feed rate and depth of cut) on performance characteristics (surface roughness, machining force and flank wear) in hard turning of AISI 4340 steel with multilayer CVD (TiN/TiCN/Al2O3) coated carbide insert. Combined effects of cutting parameter (v, f, d) on performance outputs (Ra, Fm and VB) are explored employing the analysis of variance (ANOVA). An L9 Taguchi standard design of experiments procedure was used to develop the regression models for machining responses, within the range of parameters selected. Results show that, feed rate has statistical significance on surface roughness and the machining force is influenced principally by the feed rate and depth of cut whereas , cutting speed is the most significant factor for flank wear followed by cutting speed. The desirability function approach has been used for multi-response optimization. Based on the surface roughness, machining force and flank wear, optimized machining conditions were observed in the region 147 m/min cutting speed and 0.10 mm/rev feed rate and 0.6 mm depth of cut.

Direct Yaw moment Control systems (DYC) can maintain the vehicle in the driver’s desired path by distributing the asymmetric longitudinal forces and the generation of the Control Yaw Moment (CYM). In order to achieve the superior control performance, intelligent usage of lateral forces is also required. The lateral wheel forces have an indirect effect on the CYM and based upon their directions, increase or decrease the amount of CYM magnitude. In this paper, a systematic and applicable algorithm is proposed to use the lateral force in the process of Yaw controlling optimally. The control systems are designed based on the proposed algorithm. This system includes Yaw rate controller and wheel slip controllers which are installed separately for each wheel. Both of the mentioned control systems are designed on the basis of the Fuzzy logic. Finally, the capabilities of the proposed control systems are evaluated in a four wheel drive vehicle, for which, the traction of each wheel can be controlled individually. It is shown that considering the lateral force effect offers significant improvement of the desired yaw rate tracking

In this paper, a numerical study is performed to provide the combustion and emission characteristics resulting from fuel-reactivity controlled compression ignition (RCCI) combustion mode in a heavy-duty, single-cylinder diesel engine with gasoline and diesel fuels. In RCCI strategy in-cylinder fuel blending is used to develop fuel reactivity gradients in the combustion chamber that result in a broad combustion event and reduced pressure rise rates (PRR). RCCI has been demonstrated to yield low NOx and soot with high thermal efficiency in light and heavy-duty engines. KIVA-CHEMKIN code with a reduced primary reference fuel (PRF) mechanism are implemented to study injection timings of high reactivity fuel (i.e., diesel) and low reactivity fuel percentages (i.e., gasoline) at a constant engine speed of 1300 rpm and medium load of 9 bar indicated mean effective pressure (IMEP). Significant reduction in nitrogen oxide (NOx), while 49% gross indicated efficiency (GIE) were achieved successfully through the RCCI combustion mode. The parametric study of the RCCI combustion mode revealed that the peak cylinder pressure rise rate (PPRR) of the RCCI combustion mode could be controlled by several physical parameters – PRF number, and start of injection (SOI) timing of directly injected fuel.

In this paper, the 1/4 vehicle model have been simulated. The vehicle body acceleration using optimal control has been optimized. The vehicle ride comfort is achieved by using robust control, and it has been compared with optimal control. The active suspension can help the vehicle to have a good dynamic behavioral. In this paper, two degrees of freedom dynamic vibration model of a general vehicle is developed through the designation of a closed-loop and robust control system. Irregular road input is simulated as sinusoidal signals, and the vehicle vibration response is optimized. Using robust control the vehicle ride comfort has been improved, and using optimal control not only the ride comfort has been achieved, also the vehicle acceleration is optimized.

Nonlinear vibration of parabolic springs employed in suspension system of a freight car has been studied in this paper. First, dynamical behavior of the springs is investigated by using finite element method and the obtained results are then used in vibration analysis of a railway freight car. For this purpose, dynamics of a parabolic spring subjected to a cyclic excitation has been studied in the frequency range of 2 to 15 Hz. By utilizing an experimental setup, equivalent static and dynamic stiffness and damping of the spring have been obtained and compared with theoretical results. Different classes of rail irregularities are taken into account to excite the vehicle. Bond Graph method is employed to extract the equations of motion of the system and validity of the obtained equations is investigated. Finally, a parametric study is carried out and the influence of vehicle velocity and rail irregularity on vertical acceleration of the freight car has been examined.

The natural frequencies and mode shapes of pneumatic tires are predicted using a geometrically accurate, three-dimensional finite element modeling. Tire rubber materials and cord layers are represented independently using “shell element” available in COSMOS. The effects of some physical parameters such as the inflation pressure tread pattern, thickness of belts and ply angles to the natural frequencies of tires are investigated. By imposing equivalent centrifugal forces, the effect of translational speed on vibrating behavior of the tire is also studied in this work. Comparisons of numerical and experimental results are given to show the validity of the proposed model.