|
Post Reply |
|
Thread Tools | Search this Thread |
07-10-2013, 01:16 PM | #243 |
Major General
5457
Rep 7,037
Posts |
Yes, I'm not sure why this isn't more frequently used for high output engines when VW uses it in small Seats, Golfs and people carriers it can't be very expensive or complex with today's tech. Must be some drawback otherwise you would think companies like Porsche would be allover it for their FI engines.
|
Appreciate
0
|
07-10-2013, 01:39 PM | #244 |
Lieutenant General
611
Rep 10,407
Posts |
Lancia did that in rally in their Delta S4 in 1985 (I'd also guess it has been done before then by others)! They were able to reduce turbo lag and obtain and official 480 hp from a bit less then 1.8l. Some claim they made more like 560 hp. The engine was tested up to 1000 hp.
It's a pretty good idea and a neat system. However, electronics along with clever modern controls offer flexibility and capability that systems that are essentially all mechanical just can't offer. By the way great contributions in the last few posts Boss330!
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK | | Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors | | Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels | | XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit | |
Appreciate
0
|
07-10-2013, 01:56 PM | #245 |
Major General
5457
Rep 7,037
Posts |
What some call flexible with electronics others call artificial. A mechanically driven system tends to be provide a more natural feel than an electrically powered system. I would definately prefer a twin charged engine to an electrical + mechanical turbo setup.
A sequential system like twin charging but with turbos of different sizes like some Toyota Supras would also be preferable to me. I'm not a fan of "electrifying" everything. I don't really like EPS, EDC or hybrids all feels artificial to some degree. Someone mentioned that they had talked to an M3 test driver who said something to the extent of the car having a "2nd surge of power". It sounds like some type of sequential setup wether it contains a electrical engine or is one of the mechanical systems. Last edited by solstice; 07-10-2013 at 02:31 PM.. |
Appreciate
0
|
07-10-2013, 02:31 PM | #246 | |
Major General
1715
Rep 5,110
Posts |
Quote:
It's not attached to a mechanical drive from the engine, it's propelled by the exhaust gases from the engine. That's where the issue of lag and delayed power delivery comes into play. Now, there is a solution to overcome some of the inherent issues that a turbo'd engine has. An electrical motor that is mechanically connected to the turbo and that can change the rpm of the turbine shaft. This is a more technologically advanced solution than attaching a supercharger to the crankshaft pulley. Not to mention that it doesn't steal power from the crankshaft to be driven (taking into consideration that it also can regenerate power from the turbo). Whether such a engine's power delivery will feel more artificial than a engine with a mechanically driven supercharger and a turbo is hard to tell without having testdriven one... To some, any turbo engine will feel artificial compared with a NA engine's power delivery. |
|
Appreciate
0
|
07-10-2013, 02:40 PM | #247 |
General
21117
Rep 20,741
Posts
Drives: 2021 911 turbo
Join Date: Jan 2012
Location: Montreal
|
|
Appreciate
0
|
07-10-2013, 02:44 PM | #248 | |
Major General
5457
Rep 7,037
Posts |
Quote:
Maybe none of this matter as long as there is always more pressure than used but if all of the pressure available from the low rev source is used it could matter. |
|
Appreciate
0
|
07-10-2013, 03:48 PM | #249 |
Major General
1715
Rep 5,110
Posts |
Hahaha... I know
I love a good turbo engine, but I also love a high revving NA engine as well... Some adore the power delivery and thrust of a turbo engine when it comes on boost, some feel that it's artificial and not as "pure"... |
Appreciate
0
|
07-10-2013, 03:50 PM | #250 | |
Major General
1715
Rep 5,110
Posts |
Quote:
But, yes it will be interesting to see how such a engine's power delivery will be like (if it ever comes into production). |
|
Appreciate
0
|
07-10-2013, 05:51 PM | #251 | |
Lieutenant General
611
Rep 10,407
Posts |
Quote:
__________________
E92 M3 | Space Gray on Fox Red | M-DCT | CF Roof | RAC RG63 Wheels | Brembo 380mm BBK | | Vorsteiner Ti Exhaust | Matte Black Grilles/Side Gills/Rear Emblem/Mirrors | | Alekshop Back up Camera | GP Thunders | BMW Aluminum Pedals | Elite Angels | | XPEL Full Front Wrap | Hardwired V1 | Interior Xenon Light Kit | |
|
Appreciate
0
|
07-10-2013, 06:19 PM | #252 |
First Lieutenant
15
Rep 329
Posts
Drives: 08' 335i, ZHP 330i
Join Date: Nov 2008
Location: Southeast
|
What ever happened to variable vane technology that is used on Diesel engines? Are they too big and heavy to spin up fast enough?
Just decouple a supercharger that comes online when the primary turbos run out of steam. This would carry the power to redline that everyone is so worried about. T |
Appreciate
0
|
07-11-2013, 01:57 AM | #253 | |
Major General
1715
Rep 5,110
Posts |
Quote:
An MGU can spool up the turbo from 40,000 to 120,000 rpm in less than 450 ms. That is as near as instant!!! And it's not just power to the redline that is an issue, it's response in the lower rpm scale (or turbo lag). With an MGU you can combine a fairly large turbo for high rpm's with the response (or in fact better response) of a small turbo |
|
Appreciate
0
|
07-11-2013, 02:37 AM | #254 | |
Private
5
Rep 89
Posts |
Quote:
|
|
Appreciate
0
|
07-11-2013, 05:58 AM | #255 | ||
First Lieutenant
15
Rep 329
Posts
Drives: 08' 335i, ZHP 330i
Join Date: Nov 2008
Location: Southeast
|
Quote:
T |
||
Appreciate
0
|
07-11-2013, 06:57 AM | #256 | |
Major General
1715
Rep 5,110
Posts |
Quote:
I agree that there is a possibility to take the best of both worlds, both MGU and variable vane. One doesn't necessarily eliminate the other |
|
Appreciate
0
|
07-11-2013, 07:47 AM | #257 |
Major General
6592
Rep 6,692
Posts |
If you look at the plumbing on the development car engine bay pics, the intake setup clearly points to multiple sources of combustion air.
|
Appreciate
0
|
07-11-2013, 08:15 AM | #258 | |
Major General
1715
Rep 5,110
Posts |
Quote:
|
|
Appreciate
0
|
07-11-2013, 08:34 AM | #259 | |
Major General
3487
Rep 9,709
Posts |
Quote:
And also tell us if that was a disconnected turbo, or under load? |
|
Appreciate
0
|
07-11-2013, 08:37 AM | #260 |
Major General
3487
Rep 9,709
Posts |
|
Appreciate
0
|
07-11-2013, 10:19 AM | #261 | |
Major General
5457
Rep 7,037
Posts |
Quote:
http://www.gizmag.com/vw-twincharger...he-year/15542/ |
|
Appreciate
0
|
07-11-2013, 10:36 AM | #262 |
Moderator
7512
Rep 19,368
Posts |
It seems to me that instead of separate units, the turbo and supercharger could be one integrated compressor. Essentially, a turbocharger with optional mechanical assist from the crankshaft. In fact you could add e-assist to the mix as well and then have the ECU decide how to power the turbine using various parameters depending on operating conditions.
|
Appreciate
0
|
07-11-2013, 11:19 AM | #263 | ||
Major General
1715
Rep 5,110
Posts |
Quote:
Your first question shows you don't seem to understand how a engine and a turbo works... It's kind of asking how long a length of string is How long a turbo, without MGU, takes to spool up between rpms depends on (amongst other): - Throttle position (part throttle, WOT etc) - Engine rpm - Turbine A/R - The engine's operating condition when you want the turbo to spool up (coasting, steady state driving, acceleration) - Exhaust temperature - Exhaust volume - Exhaust speed Those are some of the reasons we have something called turbo lag... With a MGU you can spool the turbo regardless of the above circumstances. This chart is from Garrett's webpage: http://www.turbobygarrett.com/turbob..._ball_bearings 400Hz = 24000rpm 2100hZ = 126000rpm So, according to Garrett, it takes between 1,6 to 2 seconds to spool up a turbo from 24000rpm to 126000rpm From 40000rpm (666Hz) to 120000rpm (2000Hz) it takes approximately 1-1,2seconds. And that is when the throttle is suddenly opened at 2000rpm on the engine. The MGU can operate idependently of engine rpm obviously. To quote Garrett engineer: Quote:
http://www.aeristech.co.uk//userFile...esentation.pdf The chart on e-Booster acceleration (1) shows that it takes 0,38s to spool from 60000rpm to 100000rpm at 0,51Bar In June this year Aeristech displayed their first low voltage system (48V). www.aeristech.co.uk Engineers at Renault F1, Garrett and others agree that a MGU/eBoost turbo can help eliminate lag, and spool up the turbo quicker than the exhaust gases can do under many circumstances. Exactly which parts of those companies engineering expertise is it that you disagree with? I'm sure Renault F1 and others would love to get some inside knowledge from you Last edited by Boss330; 07-11-2013 at 12:55 PM.. |
||
Appreciate
0
|
07-11-2013, 01:19 PM | #264 | ||
Major General
3487
Rep 9,709
Posts |
Quote:
You also can't expect an MGU to constantly keep the turbo spinning on a road car can you? Quote:
What if full boost was reached at 60,000 rpm and then the wastegate controlled turbine flow from there on? Wouldn't that mean lag ended at fractions of a second? [IMG][/IMG] I liked this graph, showing that from throttle pedal application, it was actually the standard turbo that responded marginally quicker. Without knowing other details it would be difficult to say whether for example the wastegate was starting to open thus cropping the torque gain. So a pretty meaningless comparison. No? The graph earlier in your post showing increased fuelling increased turbo response, yet they used the disadvantaged one? Last edited by NISFAN; 07-11-2013 at 01:49 PM.. |
||
Appreciate
0
|
Post Reply |
Bookmarks |
|
|