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A CAE method has been developed to address engine tonal noise and whine due to the excitation from a gerotor oil pump. The method involves a multidisciplinary approach including CFD, frequency-response structural analysis and acoustic analysis. The results from the application of the method applied to a couple of pumps with different designs are discussed. Engine tonal noise improvement through reduction in the excitation source from the pump and also stiffening the excitation path from the pump to the engine are studied. The effect of component modal alignment with oil pump orders is addressed as well.

Driveline plunge mechanism dynamics has a significant contribution to the driver's perceivable transient NVH error states and to the transmission shift quality. As it accounts for the pitch or roll movements of the front powerplant and rear drive unit, the plunging joints exhibit resisting force in the fore-aft direction under various driveline torque levels. This paper tackles the difficult task of quantifying the coefficient of static friction and the coefficient of dynamic friction in a simple to use metric as it performs in the vehicle. The comparison of the dynamic friction to the static friction allows for the detection of the occurrence of stick-slip in the slip mechanism; which enables for immediate determination of the performance of the design parameters such as spline geometry, mating parts fit and finish, and lubrication. It also provides a simple format to compare a variety of designs available to the automotive design engineer.

The Wankel rotary engine is more compact than conventional piston engines, but its oil and fuel consumption must be reduced to satisfy emission standards and customer expectations. A key step toward this goal is to develop a better understanding of the apex seal lubrication to reduce oil injection while reducing friction and maintaining adequate wear. This paper presents an apex seal dynamics model capable of estimating relative wear and predicting friction, by modeling the gas and oil flows at the seal interfaces with the rotor housing and groove flanks. Model predictions show that a thin oil film can reduce wear and friction, but to a limited extent as the apex seal running face profile is sharp due to the engine kinematics.

A deeper understanding of the complex phenomenology associated with the multiphase flow-induced noise and vibration in a dynamic valve is of critical importance to the automotive industry. To this purpose, a two-dimensional axisymmetric numerical model has been developed to simulate the complex processes that are responsible for the noise and vibration in a poppet valve. More specifically, an Eulerian multiphase flow model, a dynamic mesh and a user-defined function are utilized to facilitate the modeling of this complicated two-phase fluid-structure interaction problem. For a two-phase flow through the valve, our simulations showed that the deformation and breakup of gas bubbles in the gap between the poppet and the valve seat generates a vibration that arises primarily from the force imbalance between the spring and the two-phase fluid flow induced forces on the poppet.

The ability to evaluate the bending fatigue behavior of carburized low alloy steels in a laboratory and relate these measurements to performance of high contact ratio helical gears is important to the design and development of transmissions. Typical methods of evaluating bending fatigue performance of carburized gear steels do not directly represent helical planetary gears because they lack the geometric and loading conditions of planetary pinions. The purpose of this study is twofold; 1) development of a lab fatigue test to represent the fatigue performance of planetary pinion gears tested in a dynamometer and 2) evaluation of the influence of alloy content on bending fatigue performance of two steel alloys. The steels under evaluation were modified 8620M and 4615M alloys machined into bend bars with a notch representing a gear root and carburized to a case depth of approximately 0.35 mm (using the same carburizing cycle as the planetary pinion gears).

The liquid fuel entry into the cylinder and its subsequent behavior through the combustion cycle were observed by a high speed CCD camera in a transparent engine. The videos were taken with the engine firing under cold conditions in a simulated start-up process, at 1,000 RPM and intake manifold pressure of 0.5 bar. The variables examined were the injector geometry, injector type (normal and air-assisted), injection timing (open- and closed-valve injection), and injected air-to-fuel ratios. The visualization results show several important and unexpected features of the in-cylinder fuel behavior: 1) strip-atomization of the fuel film by the intake flow; 2) squeezing of fuel film between the intake valve and valve seat at valve closing to form large droplets; 3)deposition of liquid fuel as films distributed on the intake valve and head region. Some of the liquid fuel survives combustion into the next cycle.

INVOLUTE SPLINES enjoy three major advantages over their straight-sided counterparts: 1. New design concepts have given a more rational approach to clearances and errors. 2. Manufacturing is cheaper and more accurate. 3. Gaging is simpler. Thus, the involute spline standard of SAE and ASA continue to take precedence over the older straight-sided standards.