The Japanese manufacturer introduced an improved V6 in Canada earlier this year which played a key role in convincing Red Bull to switch from Renault to Honda for 2019.

Honda has worked on improving the reliability of its MGU-H this season but has otherwise avoided setting performance targets for its energy recovery systems.

In the British Grand Prix, Honda's deficit to Mercedes and Ferrari was estimated at a second of laptime around Silverstone, as Toro Rosso driver Pierre Gasly lamented his lack of straightline speed.

That was exacerbated by Silverstone's circuit layout, particularly the flat-out Abbey and Copse corners that effectively extend two straights, but Honda is still keen to find more performance this year with its combustion engine.

"I cannot tell you exactly yes or not, but we are still working on the ICE," Honda's F1 technical director Toyoharu Tanabe told Motorsport.com.

"I hope we will have some update and improvement within this season.

"[On Gasly's Silverstone] qualifying data we saw the performance difference on the straights.

"Of course we have [corners] here, where you can go full throttle, especially in qualifying.

"That gave us a hard time. It meant the PU performance difference here was more than at other circuits."

Honda's progress early in the season, particularly compared to Renault, buoyed Red Bull and left it optimistic about the other gains the engine maker will find before the start of the 2019 campaign.

Gasly said his frustration was not with Honda, which he said is "improving a lot", but rather with the reality that starting further behind the other engine makers gave it a "deficit that is really difficult to recover".

"It's more in terms of just pure performance and power from the engine, but I know they are working on it and they have a couple of ideas," said Gasly.

"I just need to give them time to bring it to the track, but at the moment we still lose quite a lot in terms of straightline speed.

"We still have to understand exactly how to get the best out of the Spec 2 engine."

Gasly finished 10th at Silverstone, although lost that world championship point to a post-race penalty, while his team-mate Brendon Hartley retired after one lap.

Hartley had to start from the pitlane after a suspension failure in practice destroyed his car and forced him to miss qualifying.

He was late out of the garage because of a problem installing new Honda engine parts, which led his immediate return to the pits.

"While fixing the car we had an issue with the installation on the PU side that caused an improper function," explained Tanabe.

"We saw unusual data on the PU side and we retired. I think the components are OK. We will check carefully for any damage."