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Many powertrain structural sub-systems are often tested under steady state conditions on a dynamometer or in a full vehicle. This process (while necessary) is costly and time intensive, especially when evaluating the effect of component properties on transient phenomena, such as driveline clunk. This paper proposes a laboratory experiment that provides the following: 1) a bench experiment that demonstrates transient behavior of a non-linear clutch damper under non-rotating conditions, 2) a process to efficiently evaluate multiple non-linear clutch dampers, and 3) generates benchmark time domain data for validation of non-linear driveline simulation codes. The design of this experiment is based on a previous experimental work on clunk. A commercially available non-linear clutch damper is selected and the experiment is sized accordingly. The stiffness and hysteresis properties of the clutch damper are assumed from the measured quasi-static torque curve provided by the manufacturer.

Improper roll pass designs can lead to either underfill which results in the formation of hairline cracks on the surface of the finished bars or overfill which results in roll overloading and the formation of fins. Therefore to reduce downtime, and improve yield and quality, it becomes important to design an acceptable roll pass in reasonable time. This paper presents a methodology for roll pass design which uses a three dimensional finite element technique along with an empirical procedure to arrive at an iterative scheme for reducing the number of passes and improving metal flow in the passes. This methodology is applied to improving an existing seven pass square - to - round rolling sequence, resulting in the reduction of the number of passes and improved distributions of effective strains in the rolled product.

The effectiveness of the Helmholtz resonator as a narrow band acoustic attenuator, particularly at low frequencies, makes it a highly desirable component in a wide variety of applications, including engine breathing systems. The present study investigates the influence of mean flow grazing over the neck of such a configuration on its acoustic performance both computationally and experimentally. Three-dimensional unsteady, turbulent, and compressible Navier-Stokes equations are solved by using the Pressure-Implicit-Splitting-of-Operators algorithm in STAR-CD to determine the time-dependent flow field. The introduction of mean flow in the main duct is shown to reduce the peak transmission loss and shift the fundamental resonance frequency to a higher value.

A mathematical basis for predicting loaded off-line of action contact at the tips of undermodified gear teeth is discussed. Two methods of solving the contact problem, using a modified simplex algorithm, are used to predict the load distribution. The methods differ in the compliance matrix formulation and the way they search for contact. The first method uses a tapered plate model and the second method uses a finite element model. The effects of off-line of action contact on load sharing, effective contact ratio and motion curves are shown.

A new semi-analytical framework for the study of passive or active engine mounting systems is presented. It recognizes that most practical problems incorporate a nonlinear mount or isolation element and the resulting physical system, consisting of the engine, mount and flexible base, involves many degrees of freedom. Unlike linear systems, sinusoidal excitation produces a periodic response, including super- and sub- harmonics. Two example case systems are employed to illustrate key concepts of the framework. The first numerical example case involves a passive hydraulic engine mount with an inertia track. The second example case is a novel experimental system that has been developed to study active and passive, nonlinear mounting problems. New analytical and experimental results are presented and various nonlinear phenomena are considered. The impact of nonlinearity on vibratory power transmission and active control is also investigated.

The automotive NVH research infrastructure at Ohio State includes the Center for Automotive Research, the Acoustics and Dynamics Laboratory, and the Gear Dynamics and Gear Noise Research Laboratory. This paper describes the facilities of these laboratories. Two unique existing facilities, namely the transmission error measurement of gears and a laboratory for the experimental measurement of engine breathing systems, will be emphasized. Also covered are the enhancements that are envisioned through a recent grant from the Ohio Board of Regents.

This paper presents a concept for enhancing catalytic removal of pollutant species from an exhaust stream by placing placing the plasma adjacent to the catalyst surface. Model calculations of the behavior of the electron energy distribution function (EEDF), which influences the chemistry and ionization levels near the surface, are performed and analyzed. Preliminary experiments attempting to reduce these theoretical ideas to practice in N2/NO mixtures, are discussed. Although removal of NO is observed, this is due to gas phase effects alone. The present experimental arrangement is not able to produce the requisite conditions outlined by theory to enact plasma-enhanced catalysis.

One obstacle hindering the use of port fuel injection in natural gas engines is poor idle performance due to incomplete mixing of the cylinder charge prior to ignition. Fuel injection timing has a strong influence on the mixing process. The purpose of this work is to determine the impact of fuel injection timing on in-cylinder fuel distribution. Equivalence ratio maps have been acquired by Planar Laser Induced Fluorescence in an optical engine with a production cylinder head. Experimental results have been used to determine the injection timing which produces the most uniform fuel distribution for the given engine.

In this paper, we will present parametric results of performing dynamic analysis of layshaft gear trains typically used in automotive transmissions with emphasis on the vibratory response due to transmission error excitation. A three-dimensional multiple degrees of freedom lumped parameter dynamic model of a generic layshaft type geared rotor system (with three parallel rotating shafts coupled by two sets of gear pairs) has been formulated analytically. The model includes the effects of both rotational and translational displacements of each gears, and bounce and pitch motions of the counter-shaft. The natural frequencies and mode shapes are computed numerically by solving an eigenvalue problem derived from applying harmonic solutions to the equations of motion. The complete set of mode shapes are then used in forced response calculations based on the modal expansion method to predict gear accelerations, dynamic transmission errors, mesh force and bearing loads.

Welding residual stress is one of the primary factors responsible for cracking at the access hole interface between the flange and web plate of welded heavy W-shapes. During multi-pass welding, cracks can be found in either the flange plate or the web plate, depending upon welding sequence, joint details and access hole size. In this study, an integrated numerical and experimental investigation was conducted to evaluate the effects of welding parameters and joint geometry on the magnitude and distribution of residual stresses in thick-section butt joints. The results provide guidelines for improved design for welding of heavy W-shapes.