Fuel Property, Emission Test, and Operability Results from a Fleet of Class 6 Vehicles Operating on Gas-To-Liquid Fuel and Catalyzed Diesel Particle Filters

Abstract

A fleet of six 2001 International Class 6 trucks operating in southern California was selected for an operability and emissions study using gas-to-liquid (GTL) fuel and catalyzed diesel particle filters (CDPF). Three vehicles were fueled with CARB specification diesel fuel and no emission control devices (current technology), and three vehicles were fueled with GTL fuel and retrofit with Johnson Matthey's CCRT™ diesel particulate filter. No engine modifications were made.Bench scale fuel-engine compatibility testing showed the GTL fuel had cold flow properties suitable for year-round use in southern California and was additized to meet current lubricity standards. Bench scale elastomer compatibility testing returned results similar to those of CARB specification diesel fuel. The GTL fuel met or exceeded ASTM D975 fuel properties.Researchers used a chassis dynamometer to test emissions over the City Suburban Heavy Vehicle Route (CSHVR) and New York City Bus (NYCB) cycles. The GTL-fueled vehicles were tested with and without the CDPFs to isolate fuel and aftertreatment effects.All emission changes are compared to the CARB specification diesel baseline. Over the CSHVR cycle, GTL fuel (no filter) reduced all regulated emissions, with oxides of nitrogen (NO x ) reductions of 8% and particulate matter (PM) reductions of 33%. Over the NYCB cycle, GTL fuel (no filter) reduced NO x and PM by 16% and 23%, respectively. Combining GTL and CDPF further reduced all regulated emissions, with NO x and PM reductions of 14% and 99%, respectively, on the CSHVR cycle. Vehicles tested over the NYCB cycle on GTL fuel and CDPF produced NO x and PM reductions of 20% and 97%, respectively.

Characteristics of ultrafine particle from a compression-ignition engine fueled with low sulfur diesel

“…It has also been demonstrated that some aftertreatment devices, such as DPFs, may result in very high number concentrations under certain engine operating conditions [10,11] . Many studies [12,13] found that sulfates may have significant effect on particle number emissions. However, because sulfates form a small fraction of the particulate mass (PM) emissions, lowering fuel sulfur levels has very limited potential to become an effective means to control PM.…”

Achievement of Low Emissions by Engine Modification to Utilize Gas-to-Liquid Fuel and Advanced Emission Controls on a Class 8 Truck

“…This is in agreement with previous work with DPFs. 2,10 The temperatures in the aftertreatment system were continuously monitored during testing. Figure 8 illustrates the difference in catalyst out temperature over the UDDS cycle.…”

“…Recent studies have shown the emission reduction potential of GTL fuel when used as a replacement for conventional diesel fuel, often combined with advanced emission control systems. [1][2][3] Other applications of GTL fuel include using its properties to achieve further emission reductions. Fuel properties-such as a very high paraffin content, very high cetane number, and near zero sulfur contentmake GTL fuel unique compared to even highly treated conventional diesel fuels.…”

Investigation of soot formation in Diesel-GTL fuel blends under quiescent conditions

“…As an alternative fuel to be used with LTC concepts, GTL is a promising clean low-sulfur fuel for diesel engines (Oguma et al, 2002;Oguma et al, 2004;Wu et al, 2007) due to its advantages in emission reduction, and particularly soot reduction (Alleman et al, 2004). Moreover, compared to other types of biofuels, GTL does not produce emissions of hazardous substances (Bunger et al, 2000).…”