Wave dynamics measurement and characterization of a charge air cooler at the intake of an internal combustion engine with integration into a nonlinear code

Abstract

There exist two fundamental tools for modeling and simulating wave action of internal combustion engines. The first is a nonlinear time domain solution of the Euler equations using a space-time meshing. The second is a frequency domain solution of the linear wave equations. These two methods exist with a wide range of complexity and sophistication. Hybrid coupled methods also exist; they attempt to bridge the gap between the two techniques while maintaining the overall goal of engine simulation in mind. This work deals with the frequency characterization of a complex intake element, the charge air cooler. First, a transfer matrix for a simple tube is defined and measured. Two identical versions of the previous tube serve for identifying the transfer matrix of the charge air cooler directly on an operating four-cylinder turbocharged engine. Once the transfer matrix is measured, it is coupled to GT-Power as four transfer functions coded into Simulink. The final validation comprises two tubes in GT-Power with measured boundary conditions of pressure and mass flow with the Simulink model in between. Results are presented in the time and frequency domains with future objectives and perspectives as well.

A model based system approach to innovative smart intake products: CO2 savings and specific performance

“…Initially, a methodology, using a transfer function (impedance model with flow) for the intake system, was developed for a naturally aspirated engine [3][4][5][6] in order to reduce computational times. In a next step, this methodology was modified in order to use a transfer matrix for turbocharged engines [7][8][9]. In order to establish a clear valorization of the low end torque gained by a wise setup of the pressure waves, different tests have been especially developed and applied to charge air ducts geometries [10].…”

A zonal approach for estimating pressure ratio at compressor extreme off-design conditions

“…As pollutant regulations for internal combustion engine (ICE) are becoming more restrictive year by year, manufacturers are forced to design, certify and construct new engines as fast as possible. This rush, combined with the high amount of independent variables and parameters present in the engine and its subsystems, impels the design stages to rely on gas dynamic codes such as GT-Power 1,2 and OpenWAM, 3,4 since modern computational resources are powerful enough to run numerous simulations in a short period of time. Thus, the improvement of the codes to assure accuracy and convergence of their simulations is critical.…”