Audi Confirms Diesel V6s Are HVO-Compatible

Paul Myles

TU-Editor

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23rd February 2022

Audi has now approved many of its current six-cylinder diesel engines for use with the renewable fuel hydrotreated vegetable oil (HVO).

Renewable fuels, or reFuels, make it possible to operate combustion engines in a more climate-friendly manner. This, along with mounting moves to burn hydrogen in ICE powered vehicles, create a quicker route to reducing CO2 emissions from the automotive industry than by placing all its faith in BEV technology that cannot suit the needs of most consumers.

While Audi are committed to phasing out its ICE models by 2033, it says current vehicles with its V6 diesel engines, up to and including 282bhp versions, that are leaving the company’s factories as of the middle of February can be filled up with the HVO fuel in accordance with the European standard EN 15940.

HVO is a sustainable fuel that enables CO₂ reductions of between 70% and 95% compared to fossil diesel. Another advantage of HVO is its significantly higher cetane rating, which means more efficient and cleaner combustion in comparison to conventional diesel. Residual and waste materials, such as waste cooking oil from the food industry or residues from agriculture, are used in the manufacture of HVO. By incorporating hydrogen, the oils are converted into aliphatic hydrocarbons. This modifies the properties of the vegetable oils to make them suitable for use in diesel engines. They can be added to conventional diesel, replacing fossil components, or else used unmixed as 100% pure fuel.
All V6 diesel engines with in the series A4, A5, A6, A7, A8, Q7, and Q8 that are manufactured as of mid-February 2022, can be filled up with HVO fuel. The HVO release for the Q5 will follow at the beginning of March, and then the A6 allroad in the expansion stage up to 241bhp in the summer. In addition, HVO has been approved in Europe for the four-cylinder diesel engines in the Audi A3, Q2, and Q3, which have been built since June 2021. In the models based on the modular longitudinal platform, the R4 TDI in the A4, A5, A6, A7 and Q5 series have been HVO-capable since the middle of last year in Sweden, Denmark and Italy, as market demand has been greatest in these countries to date.

HVO diesel is already available at over 600 filling stations in Europe – with most of them located in Scandinavia, where environmental requirements are particularly stringent. In Germany, only a few filling stations here and there offer HVO at present, although the trend is moving in the right direction.

“With our ‘Vorsprung 2030’ strategy, we’re pursuing the clearly defined goal that all new models we launch worldwide as of 2026 will be all-electric only. In this way, we’re making an essential contribution on the road to carbon-neutral mobility,” says Oliver Hoffmann, Chief Development Officer at Audi. “At the same time, we’re optimizing our existing combustion engine portfolio for more efficiency and lower emissions. One way we’re doing this is by creating the requisite technical foundations for the use of sustainable fuels such as HVO.”

Matthias Schober, head of powertrain development for V-TFSI, TDI, and PHEV at Audi, said: “As the cetane rating of HVO is around 30% higher, the combustibility of the engines is enhanced. The positive effects of this are particularly noticeable when cold starting. We tested the effects on various components, the performance, and exhaust emissions in specific validation runs before granting approval.”

— Paul Myles is a seasoned automotive journalist based in Europe. Follow him on Twitter @Paulmyles_