SunDiesel fuel is a biomass-to-liquid (BTL) fuel that may have certain attributes different from conventional diesel. In this investigation, 100% SunDiesel was tested both in a Mercedes A-Class (MY1999) diesel vehicle and a single-cylinder heavy-duty compression-ignition direct-injection
engine. The SunDiesel's emissions and fuel consumption were significantly better than conventional diesel fuel, especially in nitrogen oxides (NOx) reduction. In the vehicle U.S. Environmental Protection Agency (EPA), Federal Test Procedure 75 (FTP-75), and New European Drive Cycle (NEDC) tests, the carbon dioxide emissions on a mile basis (g/mile) from SunDiesel fuel were almost 10% lower than the conventional diesel fuel. Similarly, in the single-cylinder engine steady-state tests, the reductions in brake specific NOx, carbon monoxide (CO), and particulate matter (PM) are equally significant. Combustion analysis, though not conclusive, indicates that there are differences deserving further research.
Since we were testing the two fuels back-to-back in the Mercedes A-class, the drivers were able to detect the subjective drivability improvement that SunDiesel has over conventional diesel fuel in less engine harshness and odor-free exhaust. Based on the test results, it is clear that SunDiesel definitely has some advantages compared to conventional diesel, but due to the limited amount of fuel available to Argonne National Laboratory for testing, additional experiments were not performed to reveal the less desirable attributes.