View Single Post
      11-16-2014, 05:32 AM   #65
Brigadier General
Boss330's Avatar

Drives: BMW
Join Date: Mar 2012
Location: Norway, Scandinavia

iTrader: (0)

Originally Posted by Torgus
Originally Posted by Boss330 View Post
And, even a e-motor to spool up the turbo needs a separate high voltage battery system. For instance a modest 2kW output at 12V would need 167Amps... Studies from 2006 by Garret on the viability of a "e-turbo" showed that a single turbo was preferrable since that required a 2,1kW motor, while a twin turbo set up required two 1,4kW motors. The study also showed that under normal driving conditions there wasn't enough exhaust gas flow to sufficiently take advantage of the e-motor attached to the turbo as a generator. Implying that the batteries would need charging in addition to the charge available from the e-motor.

I personally find the e-turbo tech very fascinationg and hope to see that employed in road cars soon.

But, this is getting seriously off topic now. I suggest that the hybrid/turbo material/tech discussion is either closed now, or continues in a dedicated thread (like in one of the old threads that discussed hybrid turbo tech in depth).

Link to that garret article? Sounds very interesting to read.

There is no reason they would use a 12v supply, they would want to crank the voltage up much much higher.

I'm confused about there not being enough exhaust flow? The reason you want to put an electric motor to spin up the shaft is exactly that. If you have a link to when this was discussed before can you post it? I've always been very interested in that tech specifically. I would think you would want to decouple the emotor feo. The turbine once it was up to speed otherwise it's a drain.
That's why I wrote that they would need an additional high voltage circuit

And one of the main points besides turbo spool up, is to harvest electrical energy from the otherwise wasted exhaust gases. This is what the MGU-H does on the current F1 engines. MGU-H means Motor Generator Unit -Heat (heat as in exhaust gases). The MGU-H serves a dual purpose. It works as a motor and spools the turbo when boost is needed quickly, and it serves as a wastegate by braking the turbine shaft, thereby harvesting electrical energy while operating as a generator. This works great on a engine that spends most of the time either on 0% throttle or 100% throttle. On a daily driver the throttle is much more often on part throttle and too little exhaust gas flows through the turbo for the MGU-H to be able to harvest energy from the exhaust gases...

I have uploaded the Garrett PDF file as an attachment.

Here is presentation from 2003 that I just found on the subject:

An SAE article
Attached Images
File Type: pdf 910121.pdf (3.52 MB, 546 views)