Effect of Water/Fuel Emulsions and a Cerium-Based Combustion Improver Additive on HD and LD Diesel Exhaust Emissions

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• 作者：Arianna Farfaletti ; Covadonga Astorga ; Giorgio Martini ; Urbano Manfredi ; Anne Mueller ; Maria Rey ; Giovanni De Santi ; Alois Krasenbrink ; and Bo R. Larsen
• 刊名：Environmental Science & Technology
• 出版年：2005
• 出版时间：September 1, 2005
• 年：2005
• 卷：39
• 期：17
• 页码：6792 - 6799
• 全文大小：239K
• 年卷期：v.39,no.17(September 1, 2005)
• ISSN：1520-5851

文摘

One of the major technological challenges for the transportsector is to cut emissions of particulate matter (PM) andnitrogen oxides (NO_x) simultaneously from diesel vehicles tomeet future emission standards and to reduce theircontribution to the pollution of ambient air. Installation ofparticle filters in all existing diesel vehicles (for new vehicles,the feasibility is proven) is an efficient but expensiveand complicated solution; thus other short-term alternativeshave been proposed. It is well known that water/diesel (W/D) emulsions with up to 20% water can reduce PM andNO_x emissions in heavy-duty (HD) engines. The amount ofwater that can be used in emulsions for the technicallymore susceptible light-duty (LD) vehicles is much lower, dueto risks of impairing engine performance and durability.The present study investigates the potential emissionreductions of an experimental 6% W/D emulsion with EURO-3LD diesel vehicles in comparison to a commercial 12%W/D emulsion with a EURO-3 HD engine and to a Cerium-based combustion improver additive. For PM, theemulsions reduced the emissions with -32% for LDvehicles (mass/km) and -59% for the HD engine (mass/kWh). However, NO_x emissions remained unchanged, andemissions of other pollutants were actually increasedfor the LD vehicles with +26% for hydrocarbons (HC), +18%for CO, and +25% for PM-associated benzo[a]pyrenetoxicity equivalents (TEQ). In contrast, CO (-32%), TEQ(-14%), and NO_x (-6%) were reduced by the emulsion forthe HD engine, and only hydrocarbons were slightlyincreased (+16%). Whereas the Cerium-based additivewas inefficient in the HD engine for all emissions exceptfor TEQ (-39%), it markedly reduced all emissions for the LDvehicles (PM -13%, CO -18%, HC -26%, TEQ -25%)except for NO_x, which remained unchanged. The presenteddata indicate a strong potential for reductions in PMemissions from current diesel engines by optimizing thefuel composition.