The present paper assesses the empirical performance of a four-cylinder CNGDI engine with a vaned diffuser turbocharger compressor. This evaluation was performed to compare injection timing operating characteristics of engines coupled with vaneless and vaned diffuser turbocharger. Numerous start of injection (SOI) have been investigated, ranging from advanced SOI (300°CA to 180°CA bTDC) during the intake stroke to retarded SOI (180°CA to 120°CA bTDC) during the compression stroke. This experiment was conducted at a wide-open throttle (WOT) condition and the air fuel ratio is set at a stoichiometric condition. Study outcomes indicate that the vaned turbocharger increases boost pressure by an average of 50% compared to the vaneless variant. In comparison, a CNGDI engine equipped with a vaned diffuser turbocharger compressor increased brake torque by 3.66%, brake thermal efficiency (BTE) by 12.90% and volumetric efficiency by 4.75% when compared to a vaneless variant. Furthermore, a comparison of vaneless and vaned turbochargers indicates that brake specific fuel consumption (BSFC) reduced by 9.43%.
Keywords: injection timing; CNGDI; turbocharger