Statistical Process Control (SPC) represents one of the most useful methods in Quality Engineering and Lean Six-Sigma methodology, being a technique of quality process improving, which permits the errors identification before their apparition, being possible to carry out an intervention of process correction, before nonconformities occurrence. By SPC implementation, the product with "zero defects" is reached, which is the target of any industrial company. This study presents the implementation of Statistical Control Process, in a supplying company of auto components for an international automobiles company aiming to improve the quality of the technological process for steering knuckle manufacturing. Thus, sampling observations it was done by applying statistical methods, so, a number of 25 samples pieces have been preserved, each specimen containing a number of 5 pieces. After measuring and controlling the parts, a series of techniques and statistical data were used, respectively control diagrams and sheets that enabled the certainty of the process capability by using MiniTab software. The last stage was consisted in reasonable assumption for the capability of the steering knuckle technological process and its defective fractions, obtaining 2,23 the indicated value of process capability. This represents an excellent value of the capability of the steering knuckle technological process, far beyond of 1,67, the need for consideration, as representing a high-performance process, for the automotive field. According to the complex analysis of Sixpack Report, presented in the paper, it can be considered that the processing process is precise and well regulated, with a performance level of 6 s.

This paper considers the diaphragm spring of a mechanical clutch being composed by a conical disk spring and trapezoidal lamellar springs attached to the disk spring. After analytical calculation of the disk spring a numerical structural analysis was performed in order to validate the 3D model of the disk spring. A design optimization with 4 design variables was done for the disk spring and, based on the optimized design, the 3D model of the diaphragm spring was built. A 6 design variables model of the diaphragm spring was proposed for design optimization analysis having as design objective the minimization of the maximum equivalent stress during disengaging the clutch.

The paper presents the design optimization of the towing hook used in passenger cars for light trailers. For this goal the cross-section and the geometry of the longitudinal axis of the hook were parameterized so the design optimization analysis took into consideration 5 parameters as design variables. The hook's mass and the global structural safety factor were considered as design function and constraint, accordingly. A new design was built using the optimized values of the parameters and the results of the structural analysis of the optimal design were emphasized.

This paper presents some research on vehicle stability, taking into account a simplified mechanical model of cars and analyzing the stability of vehicle movement using dynamic systems theory. The paper proposes a new mathematical model for the kinematic and dynamic study of the behavior of two-axle vehicles, a model using a nonlinear link between the lateral deflection of the tire and the external forces applied to it. The mechanical model is considered a model with two degrees of freedom, taking into account the following two variables: angular velocity and linear velocity in the transverse direction. To analyze the dynamic behavior of the vehicle, two displacement situations are considered: the first case in a case of displacement with a constant turning angle and the second considered case is the case with the sinusoidal variation of the wheel turning angle. Numerical solutions for these driving situations are determined and appreciations are made regarding the character of the movement in terms of stability.

In this paper is presented an equivalent mechanical model of the vehicle, useful to find the movement of the vehicle and also is presented the matrix form of the mathematical model found for this mechanical model. This mathematical model is solved via the computer and graphical results are presented in case of linear motion with 30km/h velocity while the vehicle passes with both wheels from the left side over an obstacle.

The parameters of the braking process depend on the characteristics of the tires, and their modification has been noticed when the tread is worn. Experimentally, the increase in the braking distance (by default of the other parameters of the braking process) was found with the depth of the tread pattern. In this paper, mathematical relations are proposed to quantify the influence of the tread depth in the form of a 2nd order polynomial function. For the influence of the tire wear on the braking space, it is also proposed a dependence of the wear correction coefficient. Relationships are proposed to correct the theoretical relations for calculating the braking space and braking time with the value of the coefficient of influence thus determined.

The paper presents experimental results of the influence of carburizing time of iron powder samples on the carbon content in the sample’s depth by layers, subjected to a GCS (Gas-Carburizing Sintering) method. Sintered steel elaboration by GCS method consist of enriching the Fe powder with carbon in gas medium in a single thermal cycle including the carburising operation followed by sintering, thereby achieving the sintered carbon steel. Numerical simulations were made using Abaqus/CAE software for mass diffusion analysis in order to find the appropriate diffusion coefficient value.

In this paper, it is analyzed the effect of shocks on the kinematical parameters, linear and angular courses and accelerations, of shaping-mechanism at the function with shocks. In this scope, with experimentally recorded data it is plotted the diagram of variation (in time) of mentioned parameters obtained for the different regimes of processing for the component elements of the shaping mechanism in the case of function with shocks. It is made a comparative analysis of the laws of variation for kinematical parameters obtained for the different regimes with shocks in the conditions imposed, resulting, finally, the effect of shocks.

This paper proposes a plan mechanical model for the vehicles with two axles, taking into account the lateral deflection of the tire. For this mechanical model are determined two mathematical models under the nonlinear differential equations systems form without taking into account the action of the driver and taking into account. The analysis of driver-vehicle system consists in the mathematical description of vehicle dynamics, coupled with the possibilities and limits of the human factor. Description seeks to emphasize the significant influence of the driver in handling and stability analyzes of vehicles and vehicle-driver system stability until the advent of skidding. These mathematical models are seen as very useful tools to analyzing the vehicles stability. The paper analyzes the influence of some parameters of the vehicle on its behavior in terms of stability of dynamic systems.

In this paper it is presented the design optimization of the rear wing of a sports car. The wing profile was parameterized with three variables, the angle of attack was the fourth variable and the objective function was to minimize the lift over drag ratio. Three virtual models were considered: a model without rear wing, a model with a rear wing with initial profile and position and a model with optimized rear wing. For these three models the drag and lift coefficients were calculated for comparison along with drag and lift forces.

This paper presents a plane equivalent model of the vehicle and its mathematical model attached. The mathematical model is under a form of four differential equations system of order 1, in order to analyze the dynamic behaviour of the vehicle movement. Its goal is to determine the ranges of speed for that movement is stable or is unstable, or having chaotic character. The authors consider being necessary to know the conditions in which movements occur chaotic movements to avoid them through constructive or functional limitations. Speed ​​values ​​are identified for the behaviour of the system is placed in the quasiperiodic movements field or exceeding these movements trough chaos and are highlighted by the specific instruments: the trajectories in the phase plane, Poincare section and power spectra.

In this paper it is presented the design optimization of the diaphragm spring for a mechanical clutch. The slot shape of the fingers was parameterized and the objective function was the maximum tangential stress to be minimized subjected to the constraint that the deflection of the spring on exterior diameter in the spring centreline direction has a minimum certain value when the clutch is disengaged.

The paper presents a modal analysis for the helicoidally spring from the compound of the Macpherson automotive suspension. In the first part, it is described the device used for the experimental study and then, the measurement equipment used, too. First of all, it is represented the kinematical scheme and 3D representation for the device mechanism included the helicoidally spring necessary to the dynamic analysis. After this, are made some measurements of different parameters of the helicoidally spring obtaining the experimental values which are compared finally with the simulation results.

The paper presents a numerical simulation of the motion of a car based on a mathematical model that takes into account the lateral and longitudinal forces from the contact stain, forces given by suspension system, aero-dynamical force and weight force. In the paper is also presented the mechanical model for a vehicle upon which it was built a mathematical model. Considering the mechanical model and the mathematical model vehicle dynamics numerical simulations were made using the computing environment Matlab. Numerical simulations presented in this paper are obtained at relatively constant speeds of the car, taking into consideration a sinusoidal variation of the steering angle of the wheel: the variation of steering angle was with amplitude equal to 5° and period equal to 3 s. The results refers to the linear and angular movement and velocity, linear and angular accelerations, deformations of the tires, lateral forces.

In this paper is made a tridimensional model for the stand use for the testing of helicoidally springs from automotives suspension using Solid Works soft. Then, it is realized the simulation for the testing of helicoidally springs. On this 3D-model is realized a dynamic analysis for the stand for obtaining the variation of stresses and deformation for all parts of this stand.

In this paper the authors present the results of theoretical and experimental research in order to optimize suspension rigidity in case of Daewoo Nubira vehicle. The paper presents the mathematical model obtained by assimilating car with a dynamic system with 5 rigid solids with elastic and viscous linking between them. Theoretical results obtained based on this model and the experimental results are presented, and it is presented a solution to optimize suspension in order to remove the negative effects observed driving on gravel runways or damaged runaways. Theoretical results, compared with the experimental ones, allow us to say that it is possible to optimize suspension by analyzing specific parameters equivalent mathematical model.

This paper presents analytical expressions of the vertical reactions of the car wheels. These mathematical expressions take into account the inertia forces which are expressed by two main components of acceleration of the reference system chosen. The vertical reactions of the wheels and the torque acting on the body are determined by analytical and experimental methods in case of movement among the landmarks when the vehicle speed is 25 km/h. Theoretical results are compared with data obtained from experimental tests. Approximation values of the two data sets validates the theoretical model adopted.