Aerodynamics/Drag Coefficient

They were testing the CLA 250 and not the CLA 180 Blue Efficiency Edition which has automatic grill shutters among other optimisations to achieve 0.22 cd .

 

Yes they were testing the most aerodynamic sold in the US. The most aero car sold in europe is the VW XL1, although now I'm guessing it outputs lots of NOx, it has a drag of 3.1 sq feet, 50% of the gen III prius. Most people want more frontal area, although perhaps the shape may help.

 

The declared value for the 180 without the bluefficiency package is 0.23, still far from the measured one. BTW I think the biggest advantage of AGS on the new Prius will be reduced heating time and no need to block the grill in winter anymore

 

That's because they didn't test the 180,they testet the 250 !

CLA 180 Blue Efficiency Edition 0.22 cd
CLA 180 0.23 cd
CLA 250 0.28 cd
CLA 250 4 matic 0.29 cd
CLA 45 AMG 0.32 cd

Yes AGS probably be great in the winter.

 

Toyota didn't say "world's best Cd" at the reveal; they said "world-class Cd."

 

This is the original press release of Toyota Germany

http://www.priusfreunde.de/portal/images/fbfiles/files/TMDE_1037908.pdf

Sorry but I don't know how to copy PDF Files !

Anyway this is what Toyota says :

 

Aerodynamic elements at the back of the roof support the smooth airflow over the vehicle .
Also the TNGA Plattform makes sure there's a smooth airflow on the sides .
It's extreme wind slippery shape helps the new Prius to achieve the worldwide lowest coefficient of drag !

 

That passage isn't in the PDF you attached--is it on a different page?

As someone posted earlier in this thread, Wayne Gerdes of CleanMPG reported from the Las Vegas reveal, "Toyota says the car has a world-class coefficient of drag (Cd) so expect a 0.23 to 0.24 result helping the higher highway speed efficiency while lowering noise." Which is exactly in line with what the Japanese brochure shows.

My guess: translation error on the part of a Japanese company issuing press releases in German. To produce a car with the world's best Cd, the Prius would have to be lower than the Volkswagen XL1's Cd .189 and Mercedes CLA 180 BlueEFFICIENCY's Cd .22. However, Cd .24 puts it in the same class as the Tesla Model S, Mercedes S-class, and C-class--not the best, but respectably lower than the vast majority of cars on sale.

 

Now, if they could just lower the radar signature and become true stealth.

 

Sorry I got mixed up !
I corrected it now .
It's on page 5 right down below !
Well I guess it could be a translation error and maybe they forgot to put in the words "one of",but for some strange reasonI still don't trust that staff manual !
Toyota being so secretive up to now and then they give it all away before the big bang ?
Sorry but that doesn't make sense at all !

http://www.priusfreunde.de/portal/images/fbfiles/files/TMDE_1037908.pdf

 

Anyone else speculating a Cd of 0.21 in Eco trim with the AGS system and whatever else underneath the car?

 

Cd .24 it is.

"The body height has been reduced by 20mm and the high point of the roof has been moved 170mm forward, ensuring plenty of headroom for front seat passengers while also contributing to excellent aerodynamics and an impressive 0.24 coefficient of drag (Cd)."

 

Gen4 Prius may have the lowest air drag, not necessarily lowest coefficient.

 

there were some slides showing aero and body being most important part of MPG rise... gotta find them.

 

this is what i meant... % are from +23% gain overall from old Prius in JDM.

 

Hybrid system management improvement is huge. It makes me think why wasn't it done in Gen3.

I think the answer to that is due to the improvements in EGR, EHR in combination of active shutters that allowed the system to manage better.

 

It could also be expanded RPM and/or voltage ranges on the motors.