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Squeak and rattle has become a primary source of undesired noise in automobiles due to the continual diminishment of engine, power train and tire noise levels. This article presents a finite-element-based methodology for the improvement of rattle performance of vehicle components. For implementation purposes, it has been applied to study the rattle of a glove compartment latch and corner rubber bumpers. Results from the glove compartment study are summarized herein. Extensions to other rattle problems are also highlighted.

All dimensional measurement systems, including Coordinate Measuring Machines (CMMs), share certain common characteristic elements. These systems include one or more of the following items: a sensor, a mechanism for supporting the sensor, a device for moving the support mechanism, a technique for planning how the support mechanism will be moved, and a device for analyzing sensor data. By recognizing these common features and capitalizing on the benefits of modularity and interchangeability of these features, the next generation of measuring machines will be able to easily accommodate new sensor technology and to meet the changing demands placed on dimensional inspection processes quickly and cost effectively.

To serve the need of in-line rear axle diagnostics as well as other types of transmission inspection, an angular sensor development has been undertaken. It has resulted in a new device, incorporated into a system which performs angular error sensing at three levels. High precision of better than 0.003% in velocity variations is achieved. A continuous check of the null-error status of the devices is maintained in order to ensure maximum reliability of the readings. An easy on-site calibration check is available which eliminates the need for any precision calibrating fixture. The device is configured to accommodate a pass-through drive shaft for in-line mounting. A rugged design and immunity to rotor imperfections are advantageous in a plant environment.

Plastic fuel lines have a long history in Europe but have only recently found acceptance in the U.S. Cost and material selection have played the key roles in the past. With the advent of pressurized fuel injection systems, the environmental resistance performance criteria have become more important and plastic materials such as type 11 and 12 nylon have met the challenge and replaced metal tubing and rubber hose as the fuel line materials. The success of a plastic fuel line application depends on material selection, routing and the method of connection to the rest of the system. This paper attempts to explain the driving forces behind the historic use of plastic as a fuel line material. The main body of the paper will lay out the major design considerations which apply to fuel lines in general and will explain how these criteria, applied to plastic fuel lines, can result in a successful product.

When considering ride comfort and precision there are lots of components in the vehicle suspensions that have influence in this behavior and some ride occurrences (mainly higher frequencies) are rubber bushing responsibility but due their compliance, other vehicle attributes, steering and handling, can be affected. So the correct components tuning can maintain or improve vehicle attributes to address desired brand DNA and vehicle its specific needs. These studies were done considering the elastokinematics of front axle only due need of improve its comfort concerning higher frequencies (impacts and harshness). In addiction, correlation between subjective evaluation and objective data acquisition/post processing is desirable to optimize development time. Based in subjective directional, the activities time was reduced and final configuration reached faster.

THE AUTOMOTIVE industry has not yet taken full advantage of all the superiorand peculiar properties of the new elastomers. To accomplish this, components must be designed around the material in contrast to the more normal procedure of fitting a material to an established design. Examples of progress are: colored rubbers that withstand weather indefinitely; elastomers that seal the most deteriorating hydraulic and lubricating fluids at temperatures in excess of those practical from the standpoint of the stability of the fluids themselves and the effects of heat upon metal components; the fact that the long-sought 100,000-mile tire is imminent. This paper discusses the properties and potentials of some of the new elastomers, with some possible applications.*

This article is a new methodology to create a strong and reliable procedure to measure oil level at dealers. Most of time, commercial trucks run full loaded. Engine oil level indication systems are designed to measure oil level at that condition. However commercial trucks are assembled and sold empty and without bodies for trucks. In result of this condition, vehicles with a false indication of low engine oil level are detected at dealers' pre-delivery inspection, resulting in oil addition. This oil addition causes unnecessary costs, since vehicles are produced with maximum oil level. The methodology presented in this study analyzes and treats all variables involved in engine oil level measurements from engine production line until dealers' pre-delivery inspection

Methodology of determining coefficients of material strain energy functions of rubbers from experimental measurements of homogeneous deformations is examined within the scope of the 3rd order deformation theory [3]. Closed-form solutions of most frequently employed material testing deformations - simple tensile, pure shear and equal bi-axial deformations - are examined to reveal the shortcomings of using any one deformation in characterizing the strain energy function, In order to obtain a more representative material strain energy function, employment of more than one homogenous deformation is recommended along with improved material sampling. In situations, however, where data from simple-tensile deformation alone are available a set of constraints on the coefficients have been derived that improves the extrapolation characteristics of the fitted function.

The effect of suspension system parameters on NVH performance is presented using the results of a design of experiments analysis of a quarter-car model with elastomeric elements. The elastomeric elements are modeled using Maxwell elements with stiffness increasing with frequency. Fourteen design parameters are considered. The force spectrum acting on the sprung mass is partitioned into frequency bands. The amplitude in each frequency band as well as location and amplitudes of resonance peaks in the force spectrum are used as response variables. Major factors that effect each response variable are quantified using sensitivity coefficients. Constrained optimization studies were run to identify the minimum and maximum responses that can be expected. Suspension and bushing designers can use this work to estimate the behavior of design alternatives early in the design process.

High mileage NVH performance is one of the major concerns in vehicle design for long term customer satisfaction. Elastomeric components such as suspension bushings function as vibration isolators in a vehicle. High mileage driving tends to cause the degradation of these components which in turn results in the degradation of vehicle overall NVH performance. The present paper presents the application of CAE based robustness methodology to vehicle high mileage degradation with respect to bushing degradation. A unitized vehicle with suspension strut mounts is selected as the project vehicle. Strut mount degradation characteristics, vehicle CAE model and design of experiment are linked together to achieve vehicle response robustness. The concept and methodology arc demonstrated using a tire input which simulates road excitations as a first step toward the development of a more extensive robustness methodology which will cover other excitation conditions.

High mileage NVH performance is one of the major concerns in vehicle design for long term customer satisfaction. Elastomeric components such as suspension bushings, engine mounts and tires function as vibration isolators in a vehicle. High mileage tends to cause the degradation of these components which in turn affects vehicle overall NVH performance. The present paper discusses the characteristics of bushing degradation based on laboratory bushing test data. Vehicle subjective evaluation and CAE modeling methods are used to develop a fundamental understanding of the effects of bushing degradation on vehicle NVH performance. The concept and analysis methodology are demonstrated using the front and rear suspension strut mounts and tire inputs which simulate road excitations but they are valid for other elastomeric components such as engine mounts and excitations. The knowledge derived in the study can be used as a generic guideline in designing vehicles for high mileage NVH robustness.

Predicting the service lifetime of elastomeric automotive components is key to improving customer satisfaction over a 10 year / 150,000 mile desired lifetime. Achieving a good correlation between artificially aged components and those which have seen real customer usage can be a daunting task, considering the possible variations in climate, exposure and driver aggressiveness. In natural rubber (NR) components, the quantity and structure of the network crosslinks as a function of time can be used to explore some of the most basic aging mechanisms seen in the real world, as well as to validate protocols developed within the laboratory environment to accelerate the simulation of real-world mechanisms. This paper explores the findings of such a study on an NR engine mount, and examines the information learned by comparison between actual used components and test specimens subjected to accelerated degradation.