Does AC system sense sun position?

[balfor]

I have noticed my driver and passenger vents are blowing different temperature air at times even when the "sync" button is pressed. Just today I noticed the passenger dash vents were significantly cooler than my driver side vents, and this is with both sides set to 73, climate in auto and the sync button illuminated. The only thing I can think of for the system to do this would be sun position, the passenger side of the car was in the sun while my side was shade. I know past cars I've had, like my Acura TL, would use the nav system to know the position of the sun and adjust the vents accordingly when in auto.

Does anyone know if the system takes the sun position into account? If so it would explain the vent temps. If it does not, sounds like I have a problem with my climate control. I don't think the manual says anything about this.

 

[celltech]

There is a solar sensor behind the rear view mirror that looks at sun intensity, and the temperature sensor is around the CD slot. But I don't see anywhere in the service manual where it states it looks for sun position. Nor do I see more than 1 temperature sensor in the cabin.

 

[MikeyTG]

How could they implement different temperature settings right and left with one temperature sensor (unless they are faking it)? It seems logical that there is a sensor for each side and the side with the sun was getting warmer, hence the extra cooling.

 

[Stocks2k]

My old Acura TL used the GPS to determine solar angle and would adjust the temperature between the two front zones based on thermal loading. That was in a car made 12 years ago.

 

[jarred52]

If the 2-zone temp setting is based on position of the sum, how does the setting work after sun-down when the passenger want's a different temp than the driver?

The system only makes sense with two sensors.

 

[celltech]

I know it sounds strange that it only has the 1 temp sensor...but that is all I can find. My best guess is it has logic knowing to change the flow differential between left/right sides based on the desired delta. Looking at the manual the ductwork behind the dash is crazy complicated and I sure would hate to have to fix it. There is even an ionizer stuck in there...

 

[AustinTX]

If the 2-zone temp setting is based on position of the sum, how does the setting work after sun-down when the passenger want's a different temp than the driver?

The system only makes sense with two sensors.

All automated modern A/C systems have mathematical models that run in the A/C controller that can blow air based on one internal temperature sensor, GPS position and a sun sensor. I work with a customer who does HVAC testing for passenger cars for a big automotive OEM, and the system they get from their suppliers has the logic build in based on interior vehicle volume, position/air flow capacity of the vents, inside and outside temperature sensors, GPS location and a few other parameters.

I have been out in the desert in AZ with a bunch of the test engineers running heat testing (at 110F+) on a fleet of test vehicles. The models they A/C system suppliers use are pretty sophisticated, the OEMs mainly calibrate and tweak parameters on the controllers. They can't even change the code in the A/C system, the expertise on all that comes from the supplier.

Page 3-135 of the 2015 Hyundai Genesis manual shows the position of the sun sensor (I assume, makes sense in the context).

 

[jarred52]

I know it sounds strange that it only has the 1 temp sensor...but that is all I can find. My best guess is it has logic knowing to change the flow differential between left/right sides based on the desired delta. Looking at the manual the ductwork behind the dash is crazy complicated and I sure would hate to have to fix it. There is even an ionizer stuck in there...

I talked to my service advisor at the dealership who looked up the info. You are correct; the car has only one temperature sensor. It is a very complicated sensor but only one.

 

[MikeyTG]

All automated modern A/C systems have mathematical models that run in the A/C controller that can blow air based on one internal temperature sensor, GPS position and a sun sensor. I work with a customer who does HVAC testing for passenger cars for a big automotive OEM, and the system they get from their suppliers has the logic build in based on interior vehicle volume, position/air flow capacity of the vents, inside and outside temperature sensors, GPS location and a few other parameters.

I have been out in the desert in AZ with a bunch of the test engineers running heat testing (at 110F+) on a fleet of test vehicles. The models they A/C system suppliers use are pretty sophisticated, the OEMs mainly calibrate and tweak parameters on the controllers. They can't even change the code in the A/C system, the expertise on all that comes from the supplier.

Page 3-135 of the 2015 Hyundai Genesis manual shows the position of the sun sensor (I assume, makes sense in the context).

Does it know if it is cloudy? Seems like a lot of trouble to avoid an additional $2 sensor.

 

[celltech]

The sensor is actually described as a "solar radiation detector". It measures the amount of total solar energy. So yes, if it's cloudy then it measures less solar load.

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