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The purpose of the theme developed in this work is to increase the volume of information related to vehicle evaluation and how human perception can be translated into numbers, thus facilitating the process of definitions, refinement and analysis of its performance. Based on the discipline of psychophysics, where it is possible to study the relationship between stimulus and sensation and the use of post processing tool known as PSD (Power Spectral Density), post process the acceleration data of inputs perceived by the occupants of the vehicle, when driving in routes considered ergodic. By this, in a summarized way, get to human subjective perception of comfort. This material shows in a conceptual way a sequence of studies that were conducted to make it possible, to generate a performance classification of the subjective vehicle attribute of Smoothness, by processing values of acceleration measured the driver's seat.

The main idea from this paper is show a method to correlate the driver's subjective vibrational perception to numeric values of acceleration measured in the steering wheel. These studies came from a task realized during the development of a vehicle current in production. During the development period of this vehicle, a specific vibration was verified by subjective evaluations in the steering wheel, presenting a rotational movement. The intensity of this vibration is considered not acceptable considering the final consumer perception. From this assumption, a simplified method was used to measure this vibration and after this correlate it to the drivers' perception. The method consists in measuring the acceleration in the Y axis, tangent to the steering wheel, with the accelerometer at 12:00h position.

The aim of this paper is to describe the development process of a hydraulic power steering check valve focusing on three pillars: Better steering behavior (steering wheel kick performance), lower backpressure and lower cost in comparison to baseline. The check valve concept is based on basic principles of a one way valve: a sphere inside housing which allows flow in one direction and blocks the flow when the fluid tries to flow in the opposite direction, like an electrical diode. An experimental test procedure with objective measurements was developed in order to allow a complete and fast evaluation of the different design options. Finally, the backpressure decrease was translated to vehicle fuel economy benefit.

The lag inside shock absorbers is a very undesirable problem. Lag can hinder shock performance by interfering with the forces that control it. Unfortunately, lag is a frequent problem, for that reason, we decided to study it, we hope to understand its causes and implement solutions.