People predicting the demise of the internal combustion engine will have to wait a long time to see it from Mercedes-Benz, according to the automaker's head of sustainable research and development, Herbert Kohler.

"Maybe it will be never ever," he added.

Mercedes is one of ony a few automakers still offering a V12 engine but even that is safe for the foreseeable future.

"In 1995 we were already predicting the last V12 but there are always rich customers who want the best. In 1996 there was a new 12-cylinder. These are built in small numbers and are not damaging with consumption. It is a minor issue," said Kohler.

But the future of combustion engines at Mercedes will depend on where and how they are applied.

"Heavy trucks need a strong diesel, so it will be a long time or maybe never [before they disappear]. For passenger cars it will be more than 20 years."

However, in the next five to 10 years more than half of all Mercedes passenger cars could have some form of electrification beyond stop-start, Kohler said.

"It could be 20% to 30% for plug-in hybrids and maybe even 40%. For battery vehicles 5% to 10%, and there will be a single-digit [percentage] number of fuel cells. A lot of good work is being done on our side and by the Asians - Toyota, the Koreans and Honda. There has been real good progress in the past five to eight years. Within the next 10 years they will be commercially available."

Kohler disagrees with those people who say that all the big improvements with combustion engines have been exhausted.

"The low-hanging fruits are already harvested but, for the last 10 years, I have had experienced guys telling me there are no more additional fuel savings from engines and then they come up with another brilliant idea," he added.

"I believe our creative engineers can find another 10% savings over the next five years but it is getting more and more expensive."

Kohler believes that self-driving cars could be programmed to offer significant savings, especially if linked to the European driving cycle.

"Could we imagine autonomous driving closer to the European driving cycle to save fuel in day-to-day use? We predict it will happen. If you look at what robots are doing in assembly plants they are better than humans. Maybe it will be the same with driving."