Undoing the wrongs of the Dieselgate saga, Audi has made its diesel V6s cleaner than ever.
Volkswagen's Dieselgate emissions scandal pretty much killed off the brand's TDI offerings stateside, but that doesn't mean oil-burner alternatives have seen a decline in popularity elsewhere. The Group's latest turbodiesel engines are superb; torque-rich, smooth, and economical. Elsewhere, the striking Audi Q8, for example, is available as a 50 TDI. The 3.0-liter V6 produces 282 horsepower and 443 lb-ft of torque; good enough for a 0-60 sprint of 6.3 seconds.
But as they chase the goal of carbon-neutral mobility, carmakers are exploring any number of avenues to make this a reality. Aside from its electric cars, Audi has been exploring renewable fuel, recently approving the use of HVO (hydrotreated vegetable oil) in many of its current six-cylinder diesel engines.
"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," said Audi's Chief Development Officer, Oliver Hoffmann.
Audi says HVO can be used in models equipped with V6 diesel engines producing up to 210 kW (282 hp). However, this is limited to vehicles leaving the factory from the middle of February 2022. Amazingly, the use of sustainable fuel allows for significant CO2 reductions of between 70% and 95% when compared to conventional diesel. The Ingolstadt-based brand prioritized the most popular engine variants in order to give more customers the opportunity to use renewable fuel.
Aside from the lower emissions, another benefit of HVO is the higher cetane rating, meaning cleaner, more efficient combustion in comparison to regular diesel. "As the cetane rating of HVO is around 30 percent higher, the combustibility of the engines is enhanced," said Audi's head of powertrain development for TDI, Matthias Schober.
Used cooking oil from the food industry and residues from agriculture are used in the production. The oils are converted into aliphatic hydrocarbons by hydrogenation, altering the properties of the vegetable oils to be suitable for use in diesel engines. It's not just V6 diesel Audis that can run on the fuel, either, as the VW Touareg and other Audi models will follow suit.
HVO has already been approved in Europe for the four-cylinder diesel powertrains found in the A3, Q2, and Q3.
Over 600 gas stations across the continent offer HVO, although most are dotted across Scandinavia. In Germany, few HVO filling stations exist. Like sister company Porsche, Audi should be celebrated for its sensible approach to a sustainable future. Hopefully, HVO and Porsche's eFuel keep combustion engines around for a little bit longer.