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The work presented in this paper outlines the design and development of a new roller chain sprocket tooth form for engine camshaft drives in an effort to reduce the noise levels related to chain-sprocket meshing. The crankshaft sprocket also incorporated inclined plane Nitrile damper rings to further reduce meshing impact noise levels. Previous experimental studies have shown that roller impact during meshing is a dominant noise source in roller chain drives. Noise evaluations were conducted for several camshaft drive configurations on a 4-cylinder DOHC automotive engine in a semi-anechoic dynamometer facility. The tests included measurements of meshing frequency sound power levels and overall sound power levels. This firing engine noise and vibration experiment was done to compare the noise levels of the asymmetrical sprocket tooth profile to that of a standard ISO sprocket tooth profile.

This paper presents the results of original research conducted to evaluate the braking characteristics of passenger vehicles equipped with anti-lock braking systems (ABS) as a function of brake-pedal application force. The conditions studied in this paper are for braking on a dry, level roadway without any steering input. The objective of the paper is to study the effect of brake-pedal application force on the braking systems of common vehicles currently in-use. Comparisons are made between ABS and locked-wheel braking for each vehicle. The subject of this paper is part of the general topic of passenger vehicle dynamics and stability. Knowledge of how a vehicle performs under a variety of braking conditions is important for a variety of applications such as 1) intelligent vehicle highway systems, 2) vehicle stability and control, 3) vehicle dynamics, and 4) accident reconstruction.

This paper presents the results of original research conducted to evaluate the braking characteristics of passenger vehicles equipped with anti-lock braking systems (ABS) as a function of vehicle speed at the beginning of a braking maneuver. The conditions studied in this paper are for braking on a dry, level roadway without any steering input. The objective of the paper is to study the effect of vehicle speed on the braking systems of common vehicles currently in-use. Comparisons are made between ABS and locked-wheel braking for each vehicle. The subject of this paper is part of the general topic of passenger vehicle dynamics and stability. Knowledge of how a vehicle performs under a variety of braking conditions is important for a variety of applications such as 1) intelligent vehicle highway systems, 2) vehicle stability and control, 3) vehicle dynamics, and 4) accident reconstruction.

This paper presents the results of original research conducted to evaluate the braking characteristics of passenger vehicles equipped with anti-lock braking systems (ABS) as a function of tire inflation pressure. The conditions studied in this paper are for braking on a dry, level roadway without any steering input. The objective of the paper is to study the effect of tire inflation pressure on the braking systems of common vehicles currently in-use. Comparisons are made between ABS and locked-wheel braking for each vehicle. The subject of this paper is part of the general topic of passenger vehicle dynamics and stability. Knowledge of how a vehicle performs under a variety of braking conditions is important for a variety of applications such as 1) intelligent vehicle highway systems, 2) vehicle stability and control, 3) vehicle dynamics, and 4) accident reconstruction.

In this paper, functional analysis is employed to develop an ideal path of a vehicle undergoing a limit lane-change maneuver. Inputs to the problem are the lane width, tire-road coefficient of friction and either vehicle velocity or total longitudinal lane-change distance. Vehicle velocity is assumed to be constant. The problem is formulated using the calculus of variations. The solution technique relies on elliptic functions to achieve a closed-form solution. The synthesis of an ideal lane-change trajectory is treated as a minimal-energy-curve optimization problem with prescribed continuity and boundary conditions. The concept of critical speed is employed to limit the maximum curvature of any specified lane-change, thereby ensuring that the synthesized trajectory function describes a path that can be traversed under realistic road conditions. The analytical solution is confirmed by comparison to a numerical solution and a validated 8 degree-of-freedom vehicle model simulation.

This paper provides an exposition of the basic and some refined inertial critical speed estimation formulas. A literature review of existing inertial formulas for estimating critical cornering speed were identified for the ultimate purpose of developing a useful, compact, and more accurate speed estimation formula. Background information is presented covering the general definitions and utility of critical speed formulas. First, as a point of reference, the basic critical speed formulas are derived. Included is a list of the key assumptions on which the basic formulas are based. It is shown that the basic formulas are founded on the fundamental principles of physics and engineering mechanics; namely, Newton's Second Law and centrifugal force.

This paper covers briefly the theory of tire-road friction, coefficient of friction measurement techniques, and the vagaries of tire-road friction as they relate to critical speed estimation. A literature review of tire-road friction studies was conducted to identify the primary factors effecting the tire-road coefficient of friction. Background information is presented covering general definitions and the connection between the basic critical speed formulas and the coefficient of friction. The primary components of tire-road friction, adhesion and hysteresis, are discussed along with minor effects such as tearing, wear, waves, and roll formation. Common coefficient of friction field measuring techniques are described, including the skid-to-stop test and drag sled. Influential factors such as tire characteristics, tire inflation pressure, road conditions, and dynamic factors are reviewed.

This paper seeks to compare various models of desired, or ideal, vehicle lane-change trajectories or paths and to determine which is best based on selected criteria. Background information is presented covering the utility of lane-change maneuvers, lane-change terminology, and known desired open-loop trajectories. The performance of a vehicle may be assessed by measuring its deviation from an ideal path during simulated or actual limit lane-change maneuvers. Therefore, several techniques for assessing vehicle performance against an ideal trajectory are demonstrated. Similarly, in the present effort, performance indices such as integral penalty (cost) functions are used for assessing candidate lane-change trajectories. Therefore, ideal trajectory comparison is essentially treated as an optimization problem with prescribed continuity and boundary conditions, where a path's length, curvature, and rate of change of curvature are taken as its costs.

This paper investigates the ride comfort provided by cars equipped with passive and semi-active suspension systems. This investigation is part of a feasibility study for a high speed freeway system for the State of Texas that is proposed for the year 2020. The investigation described in this paper tested two automobiles, one with a passive suspension and one with a semi-active suspension at speeds from 30 mph to 80 mph. The two cars were identical in all other operational aspects except their suspensions. The tests determined the magnitudes of the linear accelerations of the automobiles' front passenger seat for the various testing speeds. These accelerations were converted into a form which could be compared to the International Organization for Standardization (ISO) standards pertaining to the relationship between these accelerations and rider comfort. The ride comfort at 150 mph was predicted from extrapolation of the test data.

A numerical method is presented for studying the three dimensional pressure and stress distribution conformal contact problem found in misaligned self-lubricated journal bearings. The modified Boussinesq force-displacement influence function and modified profile function are employed in conjunction with the integral equation discretization method and the mesh generation technique to analyze the contact pressure distribution and the axial contact length (separation point) within the misaligned pressure zone. The method has been implemented in a computer program and has been applied to the problems of misaligned and perfectly-aligned conformal contact. The results have been verified by comparison with the experimental data presented in the literature for the self-lubricated filament wound bearing under various conditions of load and misalignment. The agreement between the theory and experimental work is good within the framework of linear theory of elasticity.

An Indy type event with 13 university teams was held in Houston, Texas that was comparable to the 500 itself. There were protests, minor smash-ups, broken transmissions, winners and losers. This Mini-Indy competition is reviewed to aid future hosts and coordinators.