Does the new power unit and technology represent a small step in the right direction or a giant leap?
It represents a giant leap – going from internal combustion engines, naturally aspirated at about 30 per cent thermal efficiency up to engines where we’re all targeting 40 per cent thermal efficiency is a huge step, a huge introduction of new technology both on the internal combustion engine for efficiency and also on the two energy recovery systems that we’ve got on the power unit.
What do Mercedes expect to get from this project in terms of technology that can be eventually transferred to the road? Is that a long way in the future or is it already happening?
It’s already happening. The regulations were specifically written to take some of the ideas are already in the road car world, so downsizing, downspeeding and turbocharging but adding some new, interesting technologies in there such as the electric turbocharger as a specific example and those sort of projects are already being worked on.
What sort of progress in terms of efficiency do you engine manufacturers foresee over the seven-year lifecycle of these engines?
It’s a difficult one to predict. We’re working hard to improve the efficiency of the internal combustion engine to make sure that every single drop of fuel that goes in is efficiently used. That’s where working with Petronas helps tremendously to get us to the point we’re at today and to move forwards race by race with fuel developments. And then it’s just mastering the conversion efficiencies – so every single step where we’re converting the energy, just improving little by little and then with a new power unit homologated next year. I guess I’m not coming up with a prediction for exactly how much we’re going to improve year by year – but I imagine it’s going to be very similar to when we were in the naturally-aspirated era, where there were times when we thought 13,000rpm was impressive and we all ended up well over 20,000rpm. So it’ll be a similar level of development.
This year the regulation maximum amount of revs is 15,000 but on a good day you might see twelve. Do you see that changing, and if it did change do you see that helping the noise?
You’re correct with regard to the revs that we’re running on the track. I don’t see that changing, I don’t see the need for the revs to change to change the noise of the power unit. The principal reason why the engine is quieter is the turbine wheel and the muffling effect that you get from that. That’s one of the key technologies for recycling the waste energy that would normally go down the tailpipe so it’s a key aspect of the technology that we’ve got. There are other things we can do though with the tailpipe, perhaps, to change the noise.
Why is it 12,000 rpm instead of 15,000rpm?
The fundamental reason is the fuel flow rate formula so you get the 100 kilograms per hour once you’re at 10,500 rpm. If you rev an engine faster, you generate more friction and friction is the enemy of an engine and the enemy of a race car because you have to reject it to the radiators and there’s then an aerodynamic deficit from doing that. None of us want to be below 10,500 rpm but none of us want to be at high revs because all you do is create heat.