"Decarbonization" – it's a word you'll be hearing a lot going forward as automakers are gradually phasing out combustion engines to make way for an array of EVs. Audi has jumped on the electric bandwagon by announcing 2025 will be the last year when the Four Rings will introduce a new combustion-engined car. Starting with 2026, the Ingolstadt-based company is going to launch only EVs.

Come 2033, the production of cars running on fossil fuels will come to an end. However, Audi has said the ICE could live on for a few more years in China, depending on customer demand. In the meantime, the German luxury marque is updating some of its much-criticised diesel engines to run cleaner by making them compatible with renewable fuels.

Audi V6 TDI engines compatible with HVO
Audi V6 TDI engines compatible with HVO

Compatible with V6 TDIs producing up to 282 bhp (210 kilowatts), HVO stands for hydrotreated vegetable oil. It represents Audi's intermediary method to curb emissions before pulling the plug on the oil burner. Many of the six-cylinder engine configurations have been tweaked to run on the more sustainable fuel and have been leaving the factories in this cleaner setup since mid-February.

Compared to the ol' diesel, Audi claims CO2 emissions are down by a whopping 70 to 95 percent. There's also a side benefit to adopting HVO since it has a 30-percent higher cetane rating, thus enhancing the combustion process. That should pay dividends during cold winter mornings, but there are only about 600 fuel stations in Europe where you can find HVO. Most of them are located in Scandinavia and only a few are at home in Germany.

HVO-compatible TDI engines are currently available for the A4 through A8 models, along with the Q7 and Q8. Audi's engineers have prioritised the most popular diesel-fuelled models, which is why the Q5 will follow early next month. The A6 Allroad is going to receive the same treatment this summer. Elsewhere, the Volkswagen Touareg V6 TDI can also feed on sustainable fuel.

The latest decarbonisation process follows a similar method applied back in June 2021 for the Q2, A3, and Q3 models equipped with a four-cylinder turbodiesel engine. Some of the four-pot TDIs in the A4 through A7 models plus the Q5 were made compatible with HVO in select countries last summer.

In the long run, Audi and the whole Volkswagen Group will introduce combustion engines developed to accept renewable synthetic fuel.