Question re: turbos

[DougDome]

For big turbos, I understand that you need high exhaust gas flow in order to get the turbo spinning, which results in a significant amount of turbo "lag" and a deficiency of power in the lower RPM range.

Why isn't there some sort of hybrid technology out there that uses a battery to spin the turbo at lower RPM's to make up for the deficiency in exhaust flow? I understand that a lot of that lag can be mitigated with a twin turbo setup, but maybe this could be a cheaper way to make turbo engines easier to drive when there's not anemic power on the low end then a surge as you climb up the revs.

Then again, this may be a moot point because mass market turbos are tiny and have basically zero lag like the IHI and big fast expensive OEM cars either have big engines or twin turbo setups.

tl;dr - brainfart.

 

[Rockchops]

For big turbos, I understand that you need high exhaust gas flow in order to get the turbo spinning, which results in a significant amount of turbo "lag" and a deficiency of power in the lower RPM range.

Why isn't there some sort of hybrid technology out there that uses a battery to spin the turbo at lower RPM's to make up for the deficiency in exhaust flow? I understand that a lot of that lag can be mitigated with a twin turbo setup, but maybe this could be a cheaper way to make turbo engines easier to drive when there's not anemic power on the low end then a surge as you climb up the revs.

Then again, this may be a moot point because mass market turbos are tiny and have basically zero lag like the IHI and big fast expensive OEM cars either have big engines or twin turbo setups.

tl;dr - brainfart.

Electric turbochargers = leaf blowers. They don't spin high or powerful enough to pressureize air much. People will spool big turbos up at the track with NOS or have a twin charge system - either a supercharger for low RPMs that disengages at a certain point, then the turbo kicks in (there are folks who do SC fed turbos and whatnot too). New BMWs have a twin turbo system that is two stages, one small turbo for quick spooling then a valve switches it over to the big turbo for more power. Twin small turbos are the cheaper way to solve the problem on larger engines but of course they require time to spool too.

Variable geometry turbos solve all that anyway :thumbsup:

 

[Djmikeyd]

Break boosting ftw. Also twin scroll manifolds

 

[GeorgiaBII]

Variable turbos are a nightmare... We have them at work. Always getting carboned up and sticking

 

[AF-MKVI]

Hybrid Turbochargers have been in work for a long time. Garret had a hydrocharger they were working on for a while and gave up on. There is now another company that is working on a pure electric turbo, but the technology will not mature for years. The proof on concept prototype that has been in work adds only 35 hp. If / when this stuff comes of age it seems like it could ditch all the turbo lag. Idle to full boost times are around 500ms on the test model...not sure how much that would change in a scaled up model capable of supporting automotive needs.

They are about to test it at Le Mans.
http://www.aeristech.co.uk/news/aeristech-speeds-ahead-with-le-mans

All efforts up to this point have either failed miserably or have been cost prohibitive. We'll see what the future holds.