An Integrated Turbocharger Matching Program for Internal Combustion Engines

Following the global environmental concerns, many automobile manufacturers intend to produce smaller engines, aiming to lower emissions and fuel consumption. As compensation for performance reduction, these engines are equipped with turbochargers. One of the challenges is to select the right turbocharger for a specific engine. In this regard, an integrated zero-dimensional turbocharger and engine simulation program is developed, employing a quasi-steady compressible flow method. The program gives the designer the possibility of observing the performance of different compressor-turbine combinations on an internal combustion engine. Engine details such as fuel, cylinder geometry, heat transfer conditions, valve timing, and spark timing are considered within the engine modeling, and the designer can investigate their effects on the overall performance of the system. Compressor and turbine performances are predicted by their previously provided performance maps (steady-state characteristic curves) and special inter- and extrapolation methods. A new algorithm for turbocharger matching is suggested, and its logics, basic convergence loops, and thermodynamic equations have been described in detail. A database containing digitized compressor and turbine maps and details provided by different manufacturers is created and integrated into the program. An existing turbocharged engine has been tested and also simulated by the program. The accuracy of the program results is evaluated by comparing them with experimental results. The maximum error of modeling the engine and the whole simulation is 1.5% and 16%, respectively. Two other compressor-turbine combinations have been evaluated using the program, one of which is suggested as an alternative.