ryaan2904 wrote: ↑
Fri Jul 15, 2022 4:14 pm
godlameroso wrote: ↑
Thu Jul 14, 2022 1:24 am
DutchPanther wrote: ↑
Sat Jun 25, 2022 11:17 am
Core engine characteristics as in combustion characteristics because by altering the H unit's speed, you're affecting the in cylinder pressure right? and if they are affected won't the compression ignition characteristics also change?
In a way, because you reduce back pressure with higher turbine speed, which alters the pressure waves and how they reflect in the exhaust system. Since the H is also coupled to the compressor, compressor speed and thus intake pressure waves are altered. Furthermore, since Honda uses a bypass system compressor output can affect exhaust gas temperature and volume/density.
Do you mean that 'CAC exhaust bypass'? Can u explain please what that does?
It increases mass flow to the turbine increasing recovery potential. Instead of using a compressor bypass that vents to the atmosphere, or back into the intake plenum, it is routed to the turbine to give the turbine wheel an extra push which can then be harvested by the MGU-H. It also has the benefit of lowering the temperature of the turbine components by providing cooler air from the compressor, improving reliability of components.
The trend in aviation is to use bigger engines because it's more efficient to have big fans that move a lot of ambient temperature air at a slower velocity, than it is to have jets that move a little bit of air really fast. Likely this design consideration was absorbed into the Honda engine from their aircraft engineers. They may have figured that using an oversize compressor with a bypass and electronically controlled turbine wastegate offered interesting opportunities, seems to be paying off for them.
If the compressor keeps the engine fed, and the turbine spinning, then in effect it reduces the backpressure created by the turbine to the combustion process. Instead of absorbing crank power it's absorbing excess compressor power, which can then be harvested and used later or to save the battery the inconvenience of spooling up the turbo in places. Probably other strategies I missed, I'm just some guy.