The introduction of the new power unit, which follows upgrades from Ferrari, Renault and Honda, comes in time for the seventh race of the season, the previous version having contested the obligatory six races.
"The guys back at Brixworth have been working incredibly hard," Lewis Hamilton told reporters.
"It's not been the easiest beginning of the year in terms of preparing the engine," he continued. "Whilst it's an evolution of the previous years, it's not been the smoothest ride, but we've had great reliability with the first engine.
"It's always great having a new engine in that it's fresh. It's 'Phase 2', so it will have all new mods, slight improvements everywhere.
"It's not like at the beginning of the hybrid era where you took massive steps," he added, "it's just small steps. The biggest difference is that it's brand new, it's fresh. The old engine has done six races, it will have degradation etc.
"The guys have worked so hard. It's now small percentages, but they're very much appreciated.
"This is a power circuit, so it's come at the perfect time you," he concluded. "If you look at previous years, this is always the race where we bring second engine. It is phase two, so it will have all new mods, slight improvements everything."