Assessment of air management strategies on particulate number and size distributions from a 2-stroke compression-ignition engine operating with gasoline Partially Premixed Combustion concept

Abstract

Bermúdez, V.; Ruiz, S.; Novella Rosa, R.; Soto-Izquierdo, L. (2018). Assessment of air management strategies on particulate number and size distributions from a 2-stroke compression-ignition engine operating with gasoline Partially Premixed Combustion concept. AbstractThe newly designed Partially Premixed Combustion (PPC) concept has demonstrated its potential to reduce NOx and particulate matter (PM) emissions combined with highly indicated efficiencies. However, it is highly dependent of the ignition characteristics of the fuel and the air/fuel mixture preparation. Therefore, the proper selection of an injection strategy, of the combustion chamber design and of the air management strategy are critical to ensuring successful PPC operation in the full engine map. The objective of the present investigation consists of evaluating the use of multiple air management strategies over the air/fuel effective equivalence ratio (ɸ eff ) and cylinder charge reactivity and its consequent impact on particle number (PN) emissions and particle size distribution. Tests were carried out in a newly designed 2-stroke HSDI CI engine operating with PPC concept using 95 Research Octane Number (RON) gasoline fuel. A Scanning Particle Sizer (SMPS) was used to measure the size distribution of engine-exhaust particles in the range from 6.3 to 237 nm. Three different steady-state operation modes in terms of indicated mean effective pressure (IMEP) and engine speed were investigated. The experiments showed an increase in PN emissions and a progressive shift in the particles size towards larger sizes, increasing the accumulation-mode particles and reducing the nucleation-mode particles with the decreasing of the differential pressure between intake and exhaust (ΔP) and the valve overlap (OLAP) period. Finally, the particle formation process was limited by the increase in the EGR rate.

Analysis of the aftertreatment performance in HD-SI engine fueled with LPG

“…In general, methodologies for reductions of pollutants can be classified into two groups. The first group pertains to active solutions that affect engine design and its components, such as the optimization of injection systems, 3 improvements in the air management process, 4 new concepts of low-temperature combustion (LTC), 5 and the use of alternative fuels. 6 The second group involves passive solutions to reduce pollutant compounds across the exhaust line with the use ATS.…”

“…Also, PM emitted by the ICEs are composed of particles with different characteristics and properties according to their size, chemical composition, solubility, and origin. 4,27 Consequently, they are the focus of different scientific research that involve particles of diameter less than 1 mm. 28 Since such particles can persist for up to 1 week in the atmosphere, they can penetrate the human lungs and lodge in the alveoli, which can cause various forms of lung or cardiac cancers.…”