Mercedes has explained the changes it has made to its Formula 1 engine to address reliability concerns it had ahead of the new season.
The German car manufacturer's engine chief Hywel Thomas caused some intrigue recently when he suggested that Mercedes was battling some 'issues' with its 2021 engine prior to the start of testing.
Speaking now after the team revealed its new W12, he has detailed exactly what the team has done to make progress.
"We've completed some work on improving the reliability of the PU," he said.
"In 2020, we used an aluminium structure which wasn't as reliable as intended, so we've introduced a new alloy for the engine block.
"We've also made some adjustments to the Energy Recovery System, to make it more resilient.
"We've got a big challenge in 2021 with 23 races on the calendar, we will need to ensure that the reliability of the power unit is spot on. We've worked hard on that area and hopefully it's paid off."
One of the major changes that Mercedes has made is in revamping the design of its MGU-K, after feeling that the concept it used last year was not ideal.
"We introduced a complete redesign in 2020, a very different MGU-K to what we had run previously," added Thomas.
"It helped us make a solid step forwards in performance, but it was a design that turned out to be difficult to manufacture and assemble consistently.
"We had lots of examples where the MGU-K ran a full cycle and did exactly what we wanted it to do, but we also had some cases of midlife failures. For 2021, we've gone back, looked at that design and built an understanding of where the failures have come from.
"We have changed it for this year, to allow for a more consistent manufacturing route which should help to improve the reliability of the MGU-K."
Thomas also says that the revamped power unit for 2021 features a number of new ideas that he hopes will deliver a step forward in performance.
"We've got some completely new innovations that will be in the racing PU for the first time," he said.
"That was particularly challenging because last season finished late, so the winter period has been shorter than normal and has given us less time to prepare, which put extra strain on the business."
He added: "We've continued our quest for better thermal efficiency in the internal combustion engine. Most of the developments can be found in the core of the power unit, with a desire for maximum output from the combustion process.
"Hand in hand with that, we've introduced changes to the turbocharger to minimise the impact on the heat rejection. Those are probably the most striking when it comes to crank power and the performance of the power unit."