Open AccessOptimization of 2‑Stage Turbocharged Gas SI Engine Under Steady State Operation
Author(s) -
Oldřich Vítek,
Ján Máček,
J. Klíma,
Martin Vacek
Publication year - 2017
Publication title -
mecca
Language(s) - English
Resource type - Journals
eISSN - 1804-9338
pISSN - 1214-0821
DOI - 10.1515/mecdc-2017-0006
Subject(s) - turbocharger , gas compressor , automotive engineering , exhaust gas recirculation , turbine , steady state (chemistry) , control theory (sociology) , gas engine , stage (stratigraphy) , computer science , internal combustion engine , engineering , control (management) , mechanical engineering , chemistry , paleontology , biology , artificial intelligence
The proposed paper deals with an optimization of a highly-turbocharged large-bore gas SI engine. Only steady state operation (constant engine speed and load) is considered. The paper is mainly focused on theoretical potential of 2-stage turbocharging concept in terms of performance and limitation. The results are obtained by means of simulation using complex 0-D/ 1-D engine model including the control algorithm. Different mixture composition concepts are considered to satisfy different levels of NO x limit - fresh air mixed with external cooled EGR is supposed to be the right approach while optimal EGR level is to be found. Considering EGR circuit, 5 different layouts are tested to select the best design. As the engine control is relatively complex (2-sage turbocharger group, external EGR, compressor blow-by, controlled air excess), 5 different control means of boost pressure were considered. Each variant based on above mentioned options is optimized in terms of compressor/turbine size (swallowing capacity) to obtain the best possible BSFC. The optimal variants are compared and general conclusions are drawn.