Audi has released the first image of its 2014 Le Mans 24 Hours challenger ahead of a test starting at Sebring on Sunday.

The image shows that the car built to the new LMP1 rulebook retains a close resemblance to its predecessor, whose R18 e-tron quattro moniker it retains, despite regulation changes that mean it is five per cent narrower.

The release of the image 10 days ahead of the official launch of the car reflects the semi-public nature of the Sebring test.

The 2014 Audi, which will contest next year’s World Endurance Championship, has previously tested in secret.

It has undertaken a series of runs since hitting the track at the end of September.

Audi Sport boss Wolfgang Ullrich said: “We’ve reached a crucial stage in this project. After building the first prototype, testing on various racetracks is now taking centre-stage.

“The tests are mainly focused on achieving high mileage, co-ordinating the highly complex hybrid drive systems and working out an efficiency-optimised total package that has never before been as complex as this one.”

Audi is continuing the tradition of testing its prototypes at Sebring, even though it will not be racing at the Florida venue in 2014.

A statement described the venue as “the track where all new Le Mans prototypes of the Audi brand have had to prove their worth”.

The launch of the car will take place in Ingolstadt on December 18.