Impact of Varying Biodiesel Blends on Direct-Injection Light-Duty Diesel Engine Emissions

Marie-Josée Poitras; Deborah Rosenblatt; Tak W. Chan; Greg Rideout

doi:10.4271/2012-01-1313

A 1.9L turbocharged direct-injection engine representing a model year 1998-2003 Volkswagen vehicle, equipped with the OEM diesel oxidation catalyst (DOC) and exhaust gas recirculation (EGR), was tested on an eddy-current engine dynamometer with a critical flow venturi-constant volume sampling system (CFV-CVS). The engine was operated over three steady-state modes: 1600 rev/min at 54 Nm; 1800 rev/min at 81 Nm; and 2000 rev/min at 98 Nm.

Commercially available ultra-low sulfur diesel fuel (≺15 ppm S) was splash-blended with fatty acid methyl ester biodiesels derived from three different feedstocks: canola, soy, and tallow/waste fry oil. Test blend levels included: 0%, 2%, 5%, 20%, 50%, and 100% biodiesel for each feedstock.

Detailed emissions characterization included: carbon monoxide (CO), total hydrocarbons (THC), oxides of nitrogen (NO_x), nitrogen dioxide (NO₂), total particulate matter (TPM), organic and elemental carbon (OC/EC), carbon dioxide (CO₂), nitrous oxide (N₂O), methane (CH₄) and brake-specific fuel consumption (BSFC). Although this study did not investigate engine performance or the long-term effects of biodiesel operability, engine temperatures, speed, torque and power were monitored throughout the test program.

Decreases in TPM as well as OC/EC were noted with increasing bioblend levels. With the test engine fuelled with 100% tallow/waste fry oil, a decrease in TPM as high as 62% was measured. Changes in NO_x and NO₂ varied; at higher engine loads, the NO_x levels were increased with increasing biodiesel content, but NO_x levels decreased with increasing biodiesel content at lower engine loads. The NO₂ levels were unchanged with biodiesel. Changes in GHG and BSFC varied with the different bioblends and test modes. Emissions of CO and HC were found to be at or near ambient background levels.

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Impact of Varying Biodiesel Blends on Direct-Injection Light-Duty Diesel Engine Emissions 2012-01-1313

SAE MOBILUS