It’s too early to commit to just one autonomous powertrain, Honda’s Thomas Brachmann tells Paul Myles.

Carmakers are hedging their bets over powertrains to suit driverless cars simply because they still don’t know how consumers will use the technology.

For while most experts believe electrification of the powertrain for the autonomous vehicle is inevitable, the medium supplying the energy to the cars’ electric motors is still undecided.

According to Thomas Brachmann, Honda’s chief project engineer R&D Europe, hydrogen is just as likely to play a big role in driverless transportation as battery driven electric vehicles.

Speaking exclusively to TU-Automotive at this year’s Geneva Motor Show, Brachmann said any powertrain has to suit the future needs of consumers to succeed with autonomous technology.

He said: “The development of hydrogen fuel cell is one way seeing what a future powertrain should look like in order to use renewable energy to the maximum. Yet, with the recent development of autonomous drive and connected car we have to rethink what is the best powertrain for these purposes.

“One thing is very clear, it will be an electric powered vehicle. Whether that’s hydrogen fuel cell or battery is probably less important. Secondly, it comes down to what the customer wants. If you look at connected drive and autonomous driving and the cars are all having to pile up into a queue, will they be different sized cars or all the same size, small or big?”

One key area that carmakers will have to consider is the distance consumers will want to travel in most of their autonomous vehicle trips. Brachmann said: “We will have to see whether there is a difference between long-range driving or whether all trips will be relatively short distance.

“Also, is it more feasible to have public transport that is electrified rather than having lots of small cars on the roads? These will all influence our future decisions but then we have to cover so many safety critical levels to get to full autonomous driving and we need to prepare a powertrain for this type of vehicle.

“Looking at the crystal ball, it’s also a question of how is the market accepting autonomous driving in the sense of there being no need to control the car anymore and whether this will be appreciated or not.”

Brachmann also points to the issue of traffic management with driverless cars and what would the most likely systems controlling traffic be able to able to achieve.

He posited: “As to the management of autonomous driving you may see a position where you pay more for being faster than other driverless cars, then you would need an adequate powertrain. The challenge to me is how to generate this manager of the autonomous drive? Who is deciding which car should be where in the queue?”

With all these uncertainties still to resolve, it’s clear Honda will want to keep a foot in both battery and hydrogen fuel camps until the driverless car has been fully integrated into our transport networks.

This desire is also backed up by the Japanese government’s strategy to promote hydrogen as an automotive fuel source. Brachmann clarified: “For Honda, both paths are feasible and, with hydrogen, we have developed a very clever electrolyser which does not need a compressor any more, we do this via hydro-differential pressure that electrolyses with our fuel cell stack. This sits within the Japanese government’s planning for a hydrogen society.

“Almost all energy Japan uses is imported which is why they want to have a hydrogen society and this will all ramp up to the 2020 Olympics Games in Tokyo and car manufacturers are being told to work in this area. So the business case is more or less secured by the direction of the government.”

Autonomous Vehicle & ADAS Japan 2017

15 May 2017 - 16 May 2017, TOKYO, JAPAN

Autonomous Vehicle & ADAS Japan 2017 is an information and networking platform that brings together key stakeholders in the ADAS and autonomous value chain to discuss the biggest challenges, understand how the technology is evolving, and establish partnerships to enable the next phase of driving safety and autonomy.