restless wrote: ↑13 Mar 2019, 14:00
offtopic, but - is there a description how MGU-H works, what is used for energy harvesting?
I wonder if these ways are set in stone or someone can find additional routes for harvest.
The MGU-H as the name implies harvests heat energy. The heat created by the combustion engine precisely. The turbine on a turbo "blocks" the expanding heated air that just left the combustion chamber, the energy left over after the engine has combusted its fuel drives the turbine. The MGU-H is connected to this turbine. The MGU-H is also connected to the compressor, the compressor feeds the engine with oxygen to be mixed with fuel so that combustion can take place. It's a very elegant loop, the MGU-H can not only drive the compressor, it can also slow it down, thus the MGU-H is an electric motor that regulates the speed of the turbo.
It is an incredibly powerful device, because as stated, it can maintain boost pressures within a very tight range at all engine RPMs, that alone brings incredible efficiency benefits. The next way it benefits efficiency is that it can charge the battery, and it can do this any number of ways. First, when the car is at full power and the exhaust gases flow in excess of what is needed by the turbo to run the engine, the MGU-H can slow the turbo down and convert that load into electrical energy to be deployed later.
The MGU-H can transfer energy to and from the MGU-K, so the MGU-K can power the MGU-H similar to the way a supercharger works(ie with a pulley spinning the compressor). Therefore you can use the engine, to send power to the MGU-K, which then sends power to the MGU-H, which can either be used to run the turbo, or to harvest energy to the battery. This means that you can get around the 2MJ per lap harvest limit put on the MGU-K, by sending the energy to the MGU-H instead and then to the battery. The downside of this is that it costs fuel, and engine power to charge the battery this way, and it's incredibly inefficient.
However, having a lot of energy harvested in the battery(within the 4MJ pool) is a good thing because it allows you to run both the MGU-K and the MGU-H without wasting any engine power. That means the turbo is no longer choking the engine, and the crank is being helped to the tune of 160hp by the MGU-K, the result means the engine is ~50% efficient.