Aerodynamics of the new Mirage (0.27-0.31 drag coefficient varies with options)

[Alpha_One]

This is what I'm talking about. Look carefully and compare bottom grill opening between these two cars:

CVT


5-speed manual


Pictures are from here:
http://canberratimes.drive.com.au/ph...electedImage=2
http://canberratimes.drive.com.au/ph...lectedImage=12

[MetroMPG]

I've been thinking about this as well - if Mitsu was "fine tuning" the grille block to this extent, it's possible the 1.0L manual version of the car may have even more grille blocked than the 1.2. The Cd 0.27 figure referred to in the U.K. may be for that car. (Update: it is, in both Japan and the U.K.)

[MetroMPG]

Found a little more info on the Cd 0.27 reference - 2 of the 3 Mirage trim levels in the Japanese market have it. (Added info & link to source in post #1)

[MetroMPG]

So, we've seen that the car's Cd varies from 0.27 to 0.31.

How about looking at the effect of that number on fuel consumption?

I plugged the car's figures into the Aero/Rolling Resistance/Fuel economy calculator at EcoModder, and here's what it spat out, using these constants:

• Frontal area of 2.04 sq. meters / 21.97 sq. ft.
• Vehicle weight of 935 kg (865 Australian spec. curb weight + 70 kg driver) / 2060 lbs

Drag Coefficient (link to calculator for this value)	Fuel Economy (est.) at 80 km/h 50 mph	Fuel Economy (est.) at 97 km/h 60 mph	Fuel Economy (est.) at 121 km/h 75 mph	Power required to go 121 km/h 75 mph in Watts
0.27 (link)	3.63 L/100 km 64.85 mpg (US)	4.74 L/100 km 49.64 mpg (US)	6.79 L/100 km 34.66 mpg (US)	15,174.6
0.28 (link)	3.72 L/100 km 63.22 mpg (US)	4.87 L/100 km 48.26 mpg (US)	7.0 L/100 km 33.62 mpg (US)	15,645.53
0.29 (link)	3.81 L/100 km 61.67 mpg (US)	5.01 L/100 km 46.97 mpg (US)	7.21 L/100 km 32.64 mpg (US)	16,116.46
0.30 (link)	3.91 L/100 km 60.19 mpg (US)	5.14 L/100 km 45.73 mpg (US)	7.42 L/100 km 31.71 mpg (US)	16,587.40
0.31 (link)	4.0 L/100 km 58.79 mpg (US)	5.28 L/100 km 44.57 mpg (US)	7.63 L/100 km 30.84 mpg (US)	17,058.33

[Daox]

I must say I'm impressed that the cd is as low as .27. I think I'm impressed mostly because it doesn't look like a .27 car. It just looks like... a car.

[jamiec]

I agree Daox and i have seen other cars over the years you think how can that car that looks like that have a Cd rating that low.

[MetroMPG]

It's all in the details! But let's also remember to take this number with a grain of salt -- Cd measurements are said to vary from wind tunnel to wind tunnel.

But having said that, the proof is in the pudding: we're seeing that the cars are capable of very good economy, which they wouldn't get if they didn't have decent aero.

And notice that the calculated numbers above line up quite closely with the on-road numbers that Niky got when he tested speed vs. fuel economy of the 1.2L 5-speed Philippines spec car.

[MetroMPG]

Just picked up a tidbit of info I hadn't read before: apparently the "backwards baseball cap" aero spoiler is patent-pending by Mitsu.

(from the clam-shell hood to the – new patent pending – tapered rear roofline)

http://www.automotiveworld.com/news-...age-efficient/

I assume they're referring to the spoiler - surely you can't patent a "roofline" on its own.

[Eggman]

Just picked up a tidbit of info I hadn't read before: apparently the "backwards baseball cap" aero spoiler is patent-pending by Mitsu.

I assume they're referring to the spoiler - surely you can't patent a "roofline" on its own.

I'm not sure if this has been posted here yet but here are some patents related to both the "Automobile Body" and "Rear structure of vehicle". I found them by searching for a/the noted designer of our favorite little car, Hideyasu Nakagami.

US20140077525A1 US Application
USD664895S1 US Design Grant: Automobile body
US8985667B2 US Grant: Rear structure of vehicle

A rear structure 1 of a vehicle has a high mounted stop lamp 5 provided at the rear end of a vehicle body. The rear structure is configured such that regions bilaterally outward of a region, where the high mounted stop lamp is installed, on the upper surface of the rear end are inclined more steeply than a reference plane comprising an inclined surface of a roof panel 2, and that the lower surface of the high mounted stop lamp is located above a rearward field of view from the vehicle.

Maybe I'm reading it wrong but it seems the patent focuses more on the placement of the third brake light rather than aerodynamic advantages.

[jamiec]

Thats a great article you found Metro. I would think that they would be wanting a patent for the spoiler so others can't copy it and sell them. I would find it hard to belive they could patent the roof line shape to.