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A computational methodology has been developed for loss prediction in intake regions of internal combustion engines. The methodology consists of a hierarchy of four major tasks: (1) proper computational modeling of flow physics; (2) exact geometry and high quality and generation; (3) discretization schemes for low numerical viscosity; and (4) higher order turbulence modeling. Only when these four tasks are dealt with properly will a computational simulation yield consistently accurate results. This methodology, which is has been successfully tested and validated against benchmark quality data for a wide variety of complex 2-D and 3-D laminar and turbulent flow situations, is applied here to a loss prediction problem from industry. Total pressure losses in the intake region (inlet duct, manifold, plenum, ports, valves, and cylinder) of a Caterpillar diesel engine are predicted computationally and compared to experimental data.

Using a previously validated and documented CFD methodology, this research simulated the flow field in the intake region (inlet duct, plenum, ports, valves, and cylinder) involving the four cylinders (#1, #3, #4, #6) of a straight-six IC engine. Each cylinder was studied with its intake valves set at high, medium and low valve lifts. All twelve viscous 3-D turbulent flow simulation models had high density, high quality computational grids and complete domains. Extremely fine grid density were applied for every simulation up to 1,000,000 finite volume cells. Results for all the cases presented here were declared “fully converged” and “grid independent”. The relative magnitude of total pressure losses in the entire intake region and loss mechanisms were documented here. It was found that the total pressure losses were caused by a number of flow mechanisms.