Description:

Mineral liquid fuels derived from crude oil are expected to continue to play a dominant role in the transport sector for the next 20 years. Alternative fuels such as biodiesel, bioethanol and synthetic diesel fuels will become increasingly important.

The reasons for this are the scarcity of fossil fuels, environmental concerns (reduction of CO₂ emissions), the global trend towards mobility and, last but not least, EU Directive 2003/30/EC (increasing the market share of biofuels to approx. 20% by 2020). Against this backdrop, the use of fuel blends (mixed fuels) will become increasingly important. To date, a 5% (V/V) share of biodiesel in accordance with DIN EN 14214 is covered by the diesel fuel standard DIN EN 590 for mineral oil-based base fuels. Discussions are currently underway at European level to raise this limit to 7% (V/V) and to allow other fatty acid methyl esters or HVO (hydrogenated vegetable oils). The consequence of this is that, firstly, the admixture component will influence the fuel properties and, secondly, the range of variation in fuel properties will increase significantly. The latter is due to the fact that the addition of additives is permitted but not mandatory for every batch. As a result, some fuel properties (such as density, viscosity, oxidation stability, coking tendency, cold behaviour) can vary considerably.

The aim of the research project presented here is to provide a scientifically sound assessment of blended fuels (diesel/biofuel blends) in the following areas: engine combustion/combustion processes, efficiency of modern systems (e.g. DPF, SCR), reliability of exhaust aftertreatment systems over a longer operating period, lubricating oil contamination and durability of fuel-carrying components.

The investigation campaigns are to be carried out on a modern common rail (CR) diesel engine with Euro V application status. Engines from these series represent the state of the art technology that will be available in a few years and are particularly relevant for this potential analysis due to their advanced combustion development and extremely powerful maximum pressure injection systems. Conventional, sulphur-free diesel fuel (S<10ppm) in accordance with DIN EN 590 with 5% biodiesel additive is used as the reference fuel.