Grill Shutter Operation

No clue but, but I'd be fairly sure they're closed at every cold start, open at some coolant temperature, and suspect ambient temperature is not a factor. Someone with a camera duct taped to the front bumper and a scangauge monitoring coolant temp could figure it out. Or maybe do it in a driveway, if they set the car in a maintenance mode.

What the heck is "delta T" by the way? Does that mean "difference"?

 

You might be able to measure it with miniVCI.

Bob Wilson

 

Correct on the delta and difference.
Coolant temp and car speed is all it really needs to know. Perhaps whether the radiator fans are running.

 

Not sure in the Gen4 but on my old Chevy Cruze Eco I believe it shuttered at a certain speed to aide in highway mpg? Could the Gen 4 Shutters be similar or more advanced taking into account engine temps, etc...?

 

That's how they are described as working, but it is a simplfied explanation. Even the shutters on the Cruze Eco took temperatures into account.
"The air shutter system uses sensors to feel and sense wind and temperature conditions. The sensors are married to electric motors that open and close the shutters automatically. With the shutters closed at high speeds, wind drag is reduced. At lower speeds, the shutters open to maximize engine-cooling air flow. The air shutter system contributes nearly half a mile per gallon in combined city and highway driving." - Active Shutters Helping 2011 Chevrolet Cruze Eco Reach 40 MPG

 

From New Car Features:

Bob Wilson

 

i'd love to see pics. is this going to improve cold weather performance beyond epa testing?

 

The cross-section is in the shadow to the upper left of the structural strut. The hood seal is dangling in front. The barrier was not sharp enough and lighting could have been better . . . should have used a flash:

In about six months, there should be some pictures on Ebay.

Bob Wilson

 

One of those inspection cameras would be good, where the lens is at the tip of a cable.

 

No one got a GoPro?

I can see not being activated until the car is put into drive, and the warm up sequence starts. Sitting parked, there is no benefit to the shutters being closed; no air flow to block, and the fans may be coming on if the A/C is turned on before the car is driven off.

 

Don't stick your finger in there.

 

In fact there is a risk of 'cooking' all the parts in the engine compartment. In an ideal world, there would be an 'ambient' temperature sensor that would let the shutters stay open until some target temperature, say 105F (40C) was reached and then close up to retain heat. Heat is the enemy of electronics, even automotive grade.

Bob Wilson

 

Cars with an ICE do have an ambient temp sensor in the air intake for calculating the incoming air mass.
More likely, cars with active grills wait until they are moving before shutting the grill. Even fully shut, there is some air flowing into the radiator. Stopped, you don't want the fans sucking against the shutters if they need to be on.

 

It appears that these active grilles have a 'winter control mode' which deactivates them in a fixed partially open position below 5C (41F) and reactivates them at above 10C (50F), allegedly to prevent freezing malfunction.

A shame because those are the temperatures below which we would like these grilles to be blocked!

 

Is that info generally available somewhere @GreenJuice ?

 

https://priuschat.com/threads/more-details-on-active-grille-shutters-video.187589/unread