Experimental investigation on the effect of multiple injection strategies on emissions, noise and brake specific fuel consumption of an automotive direct injection common-rail diesel engine

Abstract

High-pressure common-rail injection systems nowadays allow a very high degree of flexibility in the timing and quantity control of multiple injections, which can be used to obtain significant reductions in engine noise and emissions. The aim of this study is to develop a better understanding of the relationship between injection strategies and the combustion and emission formation process. Some multiple injection strategies (pilot-pilot-main and pilot-main-after) have therefore been analysed to highlight their influence on the soot, NOx combustion noise and b.s.f.c. (brake specific fuel consumption) of a passenger car direct injection diesel engine prototype. Finally, the main combustion characteristics were determined, for each operating condition, on the basis of a heat release analysis and a correlation was attempted between the combustion parameters and emissions, noise and b.s.f.c.

Effects of a Dual-Loop Exhaust Gas Recirculation System and Variable Nozzle Turbine Control on the Operating Parameters of an Automotive Diesel Engine

“…It is well known [30], that a lower soot emission is associated to a more intense premixed combustion. Therefore, an inverse relationship is expected between these parameters, as shown in [29] and is apparent in Figure 17 for one test set for each working point. Moreover, the same correlation was verified for all the operating modes of point No.…”

“…Relationship between maximum in-cylinder pressure and brake specific NO X emissions in different operating modes. Figure 17 presents bsS values as a function of heat released in premixed mode of combustion referred to the main injection, calculated from heat release curves as defined in [29]. It is well known [30], that a lower soot emission is associated to a more intense premixed combustion.…”

The Effect of Fuel Dose Division on The Emission of Toxic Components in The Car Diesel Engine Exhaust Gas

“…The after-injection, taking place within milliseconds after the main injection, aims at afterburning all remaining solid particles, while the post-injection supports keeping proper temperature of the exhaust gas to ensure higher operating efficiency of the exhaust aftertreatment system. The abovementioned Multijet concept of fuel injection comprises five injection phases, but other systems, which now gain in popularity, divide the fuel dose into 7 or 8 parts [2,3,4,5,6].…”

Fuel concentration imaging inside an optically accessible diesel engine using 1-methylnaphthalene planar laser-induced fluorescence

“…Moreover, a well-optimized pilot injection strategy can significantly improve lowload fuel economy. 15,18 On the other hand, pilot injections are usually associated with increased soot emissions [14][15][16][17]19,20 and may increase NO x emissions unless the pilot injection is quite advanced. 14,17 Pilot injection strategies also appear well suited for application to low-temperature combustion (LTC) strategies.…”