Different Properties of Biodiesel in Comparison with Standard Diesel Fuel and their Impact on EURO VI Exhaust Aftertreatment Systems 2012-01-1733
The use of fatty acid methyl esters (FAME), often referred to as
biodiesel, instead of fossil diesel fuel is under consideration in
order to increase the share of fuels from renewable sources and to
reduce greenhouse gas emissions. In Europe, commercial diesel fuels
already contain up to 7% biodiesel. Higher biodiesel blends or the
use of pure biodiesel are probable measures to further increase the
share of fuels from renewable sources.
Due to its different feedstock and refining process, the
specification of biodiesel reveals some important distinctions in
comparison with standard diesel fuel. The current work aims to
discuss the possible implications of biodiesel utilization on the
aftertreatment systems of recent heavy-duty diesel (HDD) vehicles
compliant with EURO VI legislation.
In particular, the effect of biodiesel on heat-up operation,
i.e., the increase of the exhaust gas temperature by catalytic
combustion of fuel within a diesel oxidation catalyst (DOC), is
investigated. This operation is often used to facilitate the soot
regeneration of a diesel particulate filter (DPF) mounted
downstream of the DOC.
Engine bench testing has been performed, using two different
7-liter HDD engines. Secondary fuel injection upstream of the DOC
was conducted at different temperatures and exhaust mass flows,
comparing 100% biodiesel (B100) and a 30% biodiesel blend (B30)
with standard diesel fuel (B0). The results indicate that biodiesel
requests a higher minimum exhaust gas temperature for catalytic
combustion of the fuel within the DOC. While under the current test
conditions 625°C downstream DOC can be achieved at DOC inlet
temperature of 270°C, operation with B30 requires approximately
320°C inlet temperature to achieve the same outlet temperature.
When B100 is used for secondary fuel injection, even 34mDC inlet
temperature is required.
In order to explain the limitations of secondary fuel injection
with biodiesel and biodiesel blends at lower exhaust gas
temperatures, the evaporation characteristics of the utilized fuels
are discussed. The higher evaporation temperature level of fatty
acid methyl esters in comparison to diesel fuel is suggested to be
the main reason for the different behavior.
Citation: Kattwinkel, P., Reith, C., and Petersson, M., "Different Properties of Biodiesel in Comparison with Standard Diesel Fuel and their Impact on EURO VI Exhaust Aftertreatment Systems," SAE Technical Paper 2012-01-1733, 2012, https://doi.org/10.4271/2012-01-1733. Download Citation
Peter Kattwinkel, Christoph Reith, Martin Petersson
Umicore AG & Co. KG, Volvo Corporation
SAE 2012 International Powertrains, Fuels & Lubricants Meeting