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Due to complexities of interaction among gears and crescent-shaped island, a crescent oil pump is one of the most difficult auto components to model using three dimensional Computational Fluid Dynamics(CFD) method. This paper will present a novel approach to address the challenges inherent in crescent oil pump modeling. The new approach is incorporated into the commercial pump design tool PumpLinx from Simerics, Inc.. The new method is applied to simulate a production crescent oil pump with inlet/outlet ports, inner/outer gears, irregular shaped crescent island and tip leakages. The pump performance curve, cavitation effects and pressure ripples are studied using this tool and will be presented in this paper. The results from the simulations are compared to the experiment data with excellent agreement. The present study shows that the proposed computational model is very accurate and robust and can be used as a reliable crescent pump design tool.

A three-dimensional CFD methodology has been developed and applied to predict the pump performance, to understand pump flow dynamics, and to investigate pump flow/pressure ripple for gerotor pumps equipped in automatic transmission systems. The methodology is based on the commercial code CFD-ACE+ and the analytical focuses are the flow cavitation and pressure ripples over a wide range of engine speeds, 500rpm to 6,000rpm. The CFD results are first compared with the hardware measurements and a very good agreement has been achieved. Extensive CFD simulations are then conducted to study the effects of the inlet pressure, tip clearance, porting and the metering groove geometry on pump flow performance and pressure ripples.

In this paper we describe the development and application of a CAE methodology to investigate stresses incurred in the torque converter anti-rattle spring subjected to various static and dynamic loading conditions. The objectives of this study are three-fold. First, develop and demonstrate a dynamic modeling methodology suitable for torque converter rattle analysis. Second, provide insight into the underlying physics in the hardware design and identify key parameters to achieve high-mileage improvement, and third, recommend feasible design and manufacturing parameters for design improvements. Anti-rattle springs have been widely used in torque converter clutch to reduce rattle noise between the spline interface of the cover plate and the piston plate. They are constantly subjected to static and dynamic stresses under various vehicle operation conditions.

Ratcheting Devices are often used in automatic transmissions to provide a unidirectional power flow to achieve specific gear functions. These devices consist of two members that rotate relative to each other and a locking mechanism between these two rotating parts. In order to meet certain gearshift needs, the ratcheting device performs a combined overrun and engagement function. In both modes the components experience high-speed rotation and are subjected to significant impact forces. The high impact forces between the components may cause damage on the parts and the device may fail to function as intended. It is important to understand the dynamic behaviors of these ratcheting devices and the key design factors affecting their performances under various operating conditions. Vehicle tests and/or laboratory tests are often conducted to investigate the dynamic performance of these devices.

In this paper we describe the application of a CFD methodology to characterize the orifice flows over a wide range of flow conditions with various geometrical features commonly found in hydraulic control systems. There are three objectives in carrying out this study. First, apply CFD analyses to provide physical insight into the orifice flow physics and clarify the use of relevant engineering parameters critical to hydraulic control applications. Second, quantify orifice discharge coefficient with respect to orifice diameter ratio, cross-sectional shape, plate thickness, orifice entrance and exit geometries. Third, support physical test and establish building block elements for hydraulic system modeling. The results obtained from CFD calculations agree very well with available data published in professional handbooks and fluid mechanics related textbooks, especially in the high Reynolds number flow regime.

This paper presents a Computational Fluid Dynamic(CFD) model for the oil pump simulations aimed at better understanding the flow characteristics for improving their designs and reducing product development cycles. Several advanced numerical technologies have been developed to handle the complex geometries of oil pumps and the moving interfaces between the rotating and stationary parts. Two basic oil pump configurations, a vane oil pump and a gerotor oil pump, have been studied with the present method. The numerical results are compared with the existing experimental data.

This paper presents a novel computational method for the flow simulations in the automotive oil pumps. The objective of this effort is to develop an advanced Computational Fluid Dynamics (CFD) tool to improve oil pump designs and efficiency by detailed analysis of unsteady fluid flow patterns inside stationary and rotating passages of an oil pump. To achieve this goal, several state-of-the-art computational technologies have been implemented into a general purpose unstructured grid code to handle numerical difficulties posed by complex geometry and moving parts of oil pumps. Most challenging numerical issues resolved in this paper include moving/deforming cells inside pump pockets, arbitrary sliding interface to connect moving and stationary parts and large grid distortions due to the great volume change of the pump pockets etc. A practical validation case, a vane oil pump, is studied using the presented method. The numerical results are compared with available experiment data.