Field Evaluation of Biodiesel (B20) Use by Transit Buses

Research output: Contribution to conferencePaperpeer-review

4 Scopus Citations


The objective of this research project was to compare B20 (20% biodiesel fuel) and ultra-low-sulfur (ULSD) diesel-fueled buses in terms of fuel economy, vehicle maintenance, engine performance, component wear, and lube oil performance. We examined 15 model year (MY) 2002 Gillig 40-foot transit buses equipped with MY 2002 Cummins ISM engines. The engines met 2004 U.S. emission standards and employed exhaust gas recirculation (EGR). For 18 months, eight of these buses operated exclusively on B20 and seven operated exclusively on ULSD. The B20 and ULSD study groups operated from different depots of the St. Louis (Missouri) Metro, with bus routes matched for duty cycle parity. The B20- and ULSD-fueled buses exhibited comparable fuel economy, reliability (as measured by miles between road calls), and total maintenance costs. Engine and fuel system maintenance costs were also the same for the two groups after correcting for the higher average mileage of the B20 group. Fuel filter plugging during unseasonably cold temperatures was more prevalent for the B20 group. Lube oil samples were collected over a wide range of mileage within the drain interval, and analyses indicate reductions in soot loading and wear metals in the B20 buses. Viscosity loss and lead corrosion were greater in the B20 group, while the total base number (TBN) loss was not significantly changed.

Original languageAmerican English
Number of pages13
StatePublished - 2010
EventSAE 2009 Commercial Vehicle Engineering Congress and Exhibition, COMVEC 2009 - Rosemont, IL, United States
Duration: 6 Oct 20096 Oct 2009


ConferenceSAE 2009 Commercial Vehicle Engineering Congress and Exhibition, COMVEC 2009
Country/TerritoryUnited States
CityRosemont, IL

Bibliographical note

Posted with permission

NREL Publication Number

  • NREL/CP-540-45872

Other Report Number

  • Paper No. 2009-01-2899


  • biodiesel
  • biofuel
  • transit buses


Dive into the research topics of 'Field Evaluation of Biodiesel (B20) Use by Transit Buses'. Together they form a unique fingerprint.

Cite this