"The new regulation encourages each power unit supplier to pursue the ultimate combustion efficiency and high pressure direct injections, and many, many new technologies," he said.
Arai said that technology can then be applied on the mass production side for road cars: "That's the reason why (Honda is returning)," he told reporters.
So far, Honda has only said it will be McLaren's works supplier in 2015.
But Mercedes equips its own works team as well as three customers, Ferrari has the same model and two customers, while four F1 teams are powered by Renault.
"For year 2015, McLaren is our only customer," said Arai. "I don't think about the future, because we want to concentrate on next season."
He hinted, however, that it would make financial sense to begin selling the turbo V6 units to customer teams at a later date.
"Of course we want to have good results next season," said Arai, "(as if to say) 'Please choose our power unit for next season'.
"If teams want to use our engine or power unit, we can deliver after year 2016, but right now there are no plans," he added.
Arai said Honda's European F1 headquarters, at Milton Keynes in the UK, will be ready by June.