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In this paper, an integrated torque converter design process is described which improves converter performance while reduces the design cycle time and number of hardware iterations. The process utilizes a suite of tools to achieve the objectives. For quick and flexible geometry layout, the TORUS DESIGN TOOL is employed to create the underlying 2D-torus geometry with given packaging constraints. The BLADE DESIGN TOOL is subsequently used to generate 3D sheet-metal type profiles for the impeller, turbine, and reactor blades. The tool is equipped with a parametric capability for blade curvature and blade angle control to meet the performance requirements. The AIRFOIL DESIGN TOOL utilizes a sophisticated, parameterized algorithm to generate the desired airfoil shape around the reactor camber-line for improved performance.

An edge-based, three dimensional, characteristic-based upwind Roe/TVD unstructured flow solver with chemical kinetics and turbulence modeling for simulation of in-cylinder flowfields, CRUNCH, has been extended to improve computational efficiency and utilize multiple element types. Solution efficiency is achieved using an implicit GMRES time integration procedure which is capable of advancing the solution with very large CFL numbers. The grid motion is accomplished using an automated scheme wherein layers of cells are introduced and subsequently removed as valves increase/decrease lift and as the piston moves through its stroke. A multi-zone mesh framework allows various portions of the domain to slide past each other in a noncontiguous manner. Detailed simulations have been performed for the Ford Motor Company 4.6 liter, twin valve engine. Swirl, tumble, and cross-tumble histories compare well with prior simulations performed at Ford Motor Company.

A steady-state flowbench measures the mass and angular momentum flux (swirl and tumble) for a given cylinder head intake port design over varying valve lifts and pressure drops. From these two measurements, enhancements in volumetric efficiency and burnrate can be determined. This methodology, however, requires the production and experimental testing of multiple cylinder head castings or soft-prototypes. To help reduce the number of hardware design iterations, an analytical methodology has been developed which uses a new computational fluid dynamics (CFD) simulation tools called PowerFLOW. From a solid model of the cylinder head, PowerFLOW uses automeshing which produces a 10 million Cartesian volume mesh in 4 CPU hrs. The lattice Boltzmann technique used by PowerFLOW is inherently parallel resulting in steady-state results on this mesh in 36 CPU hrs. This paper present a comparison of numerically obtained mass flow rates from PowerFLOW to experimental flowbench data.

An innovative approach for computing in-cylinder flowfields on tetrahedral grids is developed and demonstrated. The primary focus of the preliminary work presented in this paper is the development of an efficient mesh motion scheme for realistic engine geometries. An automated cell layering technique has been devised which embeds/deletes layers of tetrahedral cells as the cylinder flow domain expands/shrinks. The ability to compute in-cylinder flows using this new “multi-zone” concept is demonstrated for a twin-valve gasoline engine.