n smikle wrote:OK mr. pedantic.
I meant one volute.
This still seems not clear. By scroll turbo engineers usually describe how many floods you introduce into the exhaust turbine. If the turbine is flooded by a separate three in one pipe from each cylinder bank a turbo for a V6 is called twin scroll. Your expression "volute" seems to describe the same thing. Twin scrolling is allowed under the 2014 regs. You may have two entries to the turbine but you may have only one turbine and one turbine stage.
Even the type of turbine is free although the use of radial units for the turbine and the compressor are widely expected reflecting the traditional design. But there is also the opportunity in the regs to come up with an axial design which has been used by turbo compounding aircraft engines in the fifties. Axial turbines would have higher efficiencies but they provide packaging challenges. My biggest gripe with the rules is that they prohibit variable geometries for the turbines and the vanes.
On the other hand that isn't quite such a problem with the hybrid electrically assisted turbo. The inclusion of the MGU-H in the regs is providing a real engineering challenge in terms of control strategies and reliability. You have to be aware that only five complete power units including the hybrid turbo and power electronics package will be available per driver next year. So if you have a turbo failure or an electric fault you loose one of your precious five units.
We are going to have some excitement I guess. Reliability will count as much as performance. I imagine that the Magneti Marelli supplied teams will be already sweating bullets when the think about the 2012 alternator experience. The MGU-H will have much more exposure to heat and will be hugely more powerful than the current alternator with a very tricky bearing solution for the whole turbo unit. So we will see dramatic failures I bet. Something we are not used to any more.