This research presents the differences between the exhaust
emission parameters when biodiesel and biodiesel blends are used
instead of Ultra-Low Sulfur Diesel (ULSD). Measurements have been
conducted on three commercial light-duty engines. The engines
include an Audi 1.9 TDI that lives up to the requirements of Euro
2, a Peugeot 1.6-liter common rail with original oxidation catalyst
and EGR that lives up to the requirements of Euro 4 and a Peugeot
1.6-liter common rail with original Diesel Particulate Filter (DPF)
and Exhaust Gas Recirculation (EGR) that lives up to the
requirements of Euro 4.
Tests were performed on a dynamometer running steady state in
five representative modes drawn from the ISO 8178 test
procedure.
The reference diesel was in accordance with EN 590. The
biodiesel blends are based on a new EN 14214 animal fatty acid
methyl ester (AFME). Biodiesel blends consisting of 20% biodiesel
and 100% biodiesel have been chosen for the different gaseous
emission measurements where NO, NO₂, CO, CO₂ and HC are measured.
Also polycyclic aromatic hydrocarbons (PAH) were measured in the
50% load mode. In order to get an insight into the nano particle
emissions from the Euro 4 and Euro 2 engines, the particle number
concentration and the particle size distribution were
characterized.
The results showed that the levels of some emission parameters
differed when biodiesel was compared with ULSD. Differences in the
emission parameters were also found when the three engine types
were compared. Especially the NO₂ emission showed a significant
difference with regard to engine types and fuels.