Experimental Investigation on the Effect of Two Different Multiple Injection Strategies on Emissions, Combustion Noise and Performances of an Automotive CRDI Engine 2016-01-0871

An emissions, combustion noise and performance study were conducted to explore the effects of two different multiple injections strategies on emissions, combustion noise and performances without altering EGR %. The experiments were done on a six cylinder inline CRDI diesel production engine. The aim of this study is to improve performances (brake specific fuel consumption [BSFC], torque) and combustion noise (reduction) using multiple injection strategies without violating emission regulations. The other objective of this carried-out analysis is to examine the influence of different operating parameters (Speed and Load) and main injection timing combined, on same multiple injection strategies (Pilot- main – after {PMA}and Early - pilot- main –after {EPMA}) by means of analyzing emissions/soot, combustion noise and performances data. The total carried-out analysis was done using a typical top-down flow chart of methodology and experimental matrices have been formulated based on DOE (design of experiments) approach. Typical engine is equipped with most familiar in cylinder NOx reduction device namely EGR and multiple injection strategy. This study shows significant differences in performances and combustion noise level among the injection strategies without penalizing the emission level. This work showed that improve tendency of BSFC level at higher engine speeds and loads, while the contradictory behavior observed at lower speeds and loads using quadruple (EPMA) injection strategy in comparison to Triple (PMA) one. Also, EPMA injection strategy provides enhanced results in reduction of combustion noise with respect to PMA. Keywords: Multiple injections, Injection strategy, Pilot injection, Main injection, after injection, brake specific fuel consumption