The use of alternative fuels and among them the biofuels of 1st
generation - fatty acid methyl esters FAME's and pure plants
oils - for propulsion of IC engines is an important objective in
several countries in order to save the fossil fuels and to limit
the CO₂ production.
The properties of bio-fuels and bio-blend-fuels can vary and
this has an impact on the operation and emissions of diesel engines
and on the modern exhaust aftertreatment systems.
The present paper represents the most important results obtained
with RME at AFHB, EMPA and EC-JRC. Most of the activities were
performed in the network project BioExDi (Biofuels, Exhaust Systems
Diesel) in collaboration between industry and research
institutes.
Following most important statements can be given about the
treated subjects: - emissions (engine-out) are influenced by RME in
the sense less CO, HC & PM, more NOx and more SOF, -
there are positive influences of RME on the functionality of DOC
and DPF due to higher reactivity of RME, no influence on SCR, - the
long term functionality of exhaust aftertreatment systems with RME
can be influenced by the potential higher availability of elements,
like Ca, Mg, Zn, P, S, K, - regarding particle mass PM: without DPF
there are slight tendencies of lowering TEQ at low load with RME
and increasing TEQ at high load of the engine; with DPF there is a
strong reduction of all toxic substances and there are no effects
of RME on PAH & TEQ.
Some practical recommendations for the users of biofuels of the
1st generation are given at the end of the paper. Generally there
is a necessity of higher costs and efforts for more frequent
service and maintenance and for the quality controls of fuel and
fuel supply chain.