The present paper proposes a novel methodology of turbocharging automotive engines to reach targeted performance. The actual method is tested and validated against simulation test results of two turbocharged diesel engines; engine I, three cylinders, 1.5 L, and engine II, six cylinders, 5.9 L. The present procedure is subdivided into four key parts; namely, database construction, selection procedure, turbocharger preliminary design, and engine modeling. Based on geometric dimensions and aerodynamic parameters provided by the preliminary design procedure, 3D geometries of the turbine and compressor are generated for each studied engine. After integrating previous data into a constructed turbocharger database, two turbochargers are selected for the engine I, while only one turbocharger for the engine II. The findings show that, at the engine speed of 4000 rpm, engine I matched with the adequate turbocharger reached a target power about 2.7%, compared to the original turbocharger equipping engine I. Furthermore, engine II reached a rated power of 299.3 kW at 2500 rpm which is slightly under the original one by 2.64 kW. The superimposition of the engine operating area on compressor and turbine maps provided satisfactory results in terms of turbocharger-engine output performance, fuel consumption, secure functioning and engine thermal strength. Finally, the main advantage of the developed methodology consists of its ability to be applied at both earlier and last stages of the engine turbocharging process or to find new adequate turbochargers to replace the original one for economic, mechanical or for safety reasons.

The present paper aims to propose an efficient methodology to match aerodynamically a 1.5 l, three cylinders downsized Diesel engine, with a selected turbocharger to boost its performance based on 1D codes and CFD simulation. In this aspect, a radial turbine’s stage was sized and designed applying 1D preliminary design in-house codes. Then, a CFD simulation was established to investigate the flow field through its components and to predict its performance. Based on the simulation data, a turbine’s map was generated via gas-dynamic simulation software. On the other hand, a turbocharger compressor was selected from a database. Therefore, the performance maps of the designed turbine and the selected compressor were matched with the engine simulation model. From the findings, the new turbocharged engine developed an operating area far from the compressor limits at the entire engine speed range, with a surge margin of 23.37% at the engine rated power. The engine thermal efficiency, brake specific fuel consumption, compressor and turbine isentropic efficiencies measured on the new turbocharged engine expressed an enhancement at the engine rated speed of about 6.79%, 6.36%, 19.91% and 3.86%, respectively, compared with the original engine. Furthermore, maximum deviations of 7.43% and 0.47% were measured between the new and the original turbocharged engines in terms of in-cylinder pressure and temperature, respectively, which guarantee the engine’s thermodynamic strength. Finally, the developed methodology reported satisfactory results in terms of the engine’s secure functioning and predicted performances, which can be considered as an important basis before initiating any detailed conception.

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