Renault Sport F1's director of operations Remi Taffin says the manufacturer's dyno work over the summer break has yielded "good results" for the rest of this season and 2016.
Renault is yet to use any of its 12 engine development tokens this season despite falling further off the pace of Mercedes and Ferrari since the start of the year. That poor start has strained relations with Red Bull, with whom it won four consecutive world titles before the introduction of the V6 turbos, and the French company's future in the sport remains unclear.
Taffin says Renault has used the summer to work on this season's performance but also concepts it hopes to carry into 2016.
"We've been extremely busy in the four weeks since the Hungarian Grand Prix," Taffin said. "In contrast to the teams, who had to shut their factories, we've been operating throughout the summer break to continue our development programme. The dynos have run as usual and we've conducted some notable performance work for the rest of the season and also concepts for next year. The results are good."
Despite going into the summer break with a double Red Bull podium in Hungary Taffin is keeping his expectations in check ahead of trips to two power circuits in Spa and Monza.
"In parallel we have been preparing for Spa, which presents the hardest test of the year for the power units. The wide open throttle time is as high as Monza, but it's the corners, changes of altitude and length that increase the difficulty.
"We are realistic about the challenge facing us and the strength of the opposition at this point in time. The double podium in Hungary - and our win last year in Spa - show anything is possible so we go there in this frame of mind: concentrate on our job, do the best we can and take advantage of the circumstances as they come about."