Active Shutter Grille Vents: How They Help Improve MPG

Follow Nikki

2011 Chevrolet Cruze Eco Quick Drive and Live Photos

2011 Chevrolet Cruze Eco Quick Drive and Live Photos

Enlarge Photo

Over the past few years, more automakers than ever have started to promote something called active shutter grille vents. 

Essentially a way to boost fuel economy at higher speeds, active grill shutters are now being used by GM, Ford, and Chrysler--among others--to give gas mileage boosts to their highest-efficiency models.

But what are active shutter grille vents, and how do they work?

In a conventional, front-engined, water-cooled, gasoline car, air is drawn through the grille and into the engine bay, either sucked in by the radiator fan, or forced in by the movement of the car through the air.

The majority of that air then passes through the fins of the radiator located directly behind the grille, helping cool down the coolant within, which in turn keeps the engine cool. 

Unless that engine is working extremely hard, or is in a hot climate, however, there is often more air entering the engine bay than is needed to keep the engine cool. 

Moreover, that unnecessary air entering the engine bay can add significant aerodynamic drag to the car, increasing the amount of energy needed to move it along and thus decreasing gas mileage. 

The higher the speed, the higher the aerodynamic drag. 

It’s at those higher speeds, when the active shutter comes into play. 

2013 Ford Escape, launched at the Los Angeles Auto Show, Nov 2011

2013 Ford Escape, launched at the Los Angeles Auto Show, Nov 2011

Enlarge Photo

Using a series of small shutters similar to the ones you’d find on certain window blinds--and an electric motor--cars like the Chevrolet Cruze Eco, Ford Focus SFE and Dodge Dart Aero can automatically close part or all of the grille, reducing or stopping the air flow to the engine bay.

The reduction in air flow reduces drag, making the car slip through the air more easily. This, in turn, reduces the amount of energy needed to push the car along, increasing gas mileage. 

If the engine gets too hot, the active shutter system can automatically reopen the grille, ensuring much-needed air can reach the radiator and prevent engine overheating. 

Like engine stop-start and turbocharged engines, active shutter grille vents can help improve your gas mileage by a few mpg over an identical model without them fitted. 

And with more cars than ever, including the 2013 Ford Escape EcoBoost 1.6-liter and even the 2013 Ram 1500, turning to active shutter grille vent technology to save gas, it’s certainly worth checking to see if your next car has this cheap yet effective fuel saving technology fitted. 


Follow GreenCarReports on Facebook and Twitter.

Follow Us

Comments (13)
  1. I wonder if air temperature is a factor at all. Seems like in really cold weather, the grille could be completely closed without risking overheating the engine.

  2. John, it is. If there is no need to cool the engine, then the grills remain shut, at least on the one system that I worked with.

    This is a perfect example of a minor cost that yields positive results.

  3. Thanks kindly for the additional information.

  4. I suspect that almost the entire cooling system on my Fluence ZE is unnecessary most of the time. I can drive at 130km for an hour, pull over and place both palms flat on the "hood" (shudders after talking American) of the car. Not really sure why I'm even carrying an enormous radiator. Probably need one, but surely not that big!

  5. You would need that if you drive between Barstow CA and Las Vegas, NV on a really hot day climbing up the hill...

  6. This technology should have been used long time ago...

  7. It actually was used a few times a long time ago, but just never really caught one. BMW used it long ago on the M3/M5, I believe. But with CAFE coming up, you'll see it on almost all new vehicles soon. 100% of pickups will have it by the end of 2014. Well, 100% of the Detroit 3 pickups, anyway, I can't comment on the Japan 3. All three D3 compacts have it now, too; Cruze, Fusion, Dart, too.

  8. Err... "caught on," not caught one...

  9. Good to know. When are all the cars going to add underbody panels and better air dams?

  10. They're both coming. Underbody panels are common now, I believe. At least the latest compacts or subcompacts seem to have them.

  11. Cool little video from Magna on active grille shutters.

  12. See the large radiator is still blocking up the air and add on top of that the shutter resistance. There is a better method to do this with an adaptive fairing on the front of cars and light trucks. see the "adaptive fairing with tunneling" in the 2014 design contest on create the future website.


Commenting is closed for old articles.

Get FREE Dealer Quotes

From dealers near you

Find Green Cars


© 2015 Green Car Reports. All Rights Reserved. Green Car Reports is published by High Gear Media. Send us feedback. Stock photography by izmo, Inc.