The effects of using neat and blended (30% vol.) biodiesel,
obtained from Rapeseed Methyl Ester (RME) and Jatropha Methyl Ester
(JME), in a Euro 5 small displacement passenger car diesel engine
have been evaluated in this paper.
The impact of biodiesel usage on engine performance at full load
was analyzed for a specifically adjusted ECU calibration: the same
torque levels measured under diesel operation could be obtained,
with lower smoke levels, thus highlighting the potential for
maintaining the same level of performance while achieving
substantial emissions benefits.
In addition, the effects of biodiesel blends on brake-specific
fuel consumption and on engine-out exhaust emissions (CO₂, CO, HC,
NOx and smoke) were also evaluated at 6 different part
load operating conditions, representative of the New European
Driving Cycle. Emissions were also measured at the DPF outlet, thus
providing information about after-treatment devices efficiencies
with biodiesel. The application of a specifically adjusted engine
calibration showed a rise of fuel consumption, due to the lower
energy content of biodiesel, at same fuel conversion efficiency and
comparable CO₂ emissions. An appreciable increase of CO and HC
emissions at low load could be noticed, along with a considerable
smoke emission reduction.
Finally, soot-NOx trade-off were also analyzed for
three different engine operating points, in order to gather
detailed information about further possible emissions benefits that
could be achieved through a more extensive ECU recalibration.