Mercedes explains how W11 design tackles cooling issues
The Mercedes Formula 1 team has focussed on improving the cooling package of the new W11 – and that process has been helped by the 2020 power unit operating at a higher temperature than its predecessor.
Last year's W10 had cooling issues that the team could not fully address during the season because of limitation on radiator capacity.
The weakness was especially apparent in the Austrian GP, when extremely hot weather compromised the overall performance of the car.
"We've improved the cooling package," said technical director James Allison. "We've created more face area – so more actual radiator area in the car – which is a difficult thing to do mid-season without incurring quite a lot of penalty.
"But between the years you can do it and it won't cost you except a little bit of weight.
"We've also benefitted from an investment that HPP have made on our behalf. They've worked to raise the operating temperature of the engine which eases the cooling burden on us because the hotter the fluid, the less radiator you need to cool it."
HPP engine boss Andy Cowell explained that the process had begun last year – even before Austria – but the team has taken another step in 2020.
"At the beginning of last year, the cooling capacity of our car was insufficient, which resulted in some challenging races," said Cowell. "At the opening two races, when it became clear we didn't have enough cooling capacity, we started working on proving out the power unit at higher temperature limits.
"By Austria we had managed to prove out an extra four degrees on the water temperature which helped make the Spielberg race slightly more bearable, but it was still a very painful weekend for the team.
"Since then, we have continued that trajectory, so we're trying to contain the total heat rejection that needs to be cooled by the chassis cooling systems.
"For this year, we are putting significant effort into making sure that all the cooling fluids on the power unit operate at a higher temperature. This increases the temperature difference between that coolant fluid and the ambient temperature that we are racing in, which increases the effectiveness of the cooling system.
"That's a tough challenge though, because large parts of the engine are made from aluminium and the temperatures that we are operating at mean the material properties are decaying quite rapidly.
"Managing that over an eight-race distance power unit cycle is a tough engineering challenge but that's what we are striving for."
Cowell stressed that the engine side of the team has to help the chassis side.
"As power unit engineers we don't just focus on crankshaft power, we also focus a tremendous amount on the packaging and reducing the overheads for the aerodynamicist, so that they can mainly focus on keeping the car planted through the corner."
Mercedes has also placed a focus on reliability after some issues in 2019, although world champion Lewis Hamilton finished the season without penalty.
"We were very pleased and proud of the reliability achieved with Lewis' hardware," said Cowell. "But we were saddened by the low-life failures that we experienced with other drivers and that's what we are focusing on.
"We are concentrating on understanding the reasons, the quality issues that we encountered and we are working hard to make sure we have got robust containment in place based on the root cause of those issues.
"Twenty-two races mean one power unit needs to do eight races, so there is an increase in the number of cycles that all the hardware needs to do, putting an even bigger emphasise on reliability."
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