cabanalane

I know how it works. Did my reads, and tried it out.

But let me ask this question. Please follow so you'll get to the question.

Let's say it's cold in the morning, 40 degrees. I set it to 72 degrees. The heater actually kicks in. Arrived at Starbucks. Turn off the system. Turn off the car. Get out buy my coffee.

When I get back into the car, start it. But leave the system off. The last setting was 72. Outside is still cold. So the natural air coming in is warm.

That make sense, because I last turn off the system when there is a need to heat the car. So it's still on the heater setting.

Now it's 5pm. The sun is out. It's 80 degrees outside. When I start the car and start driving. Natural air starts to come in from the vents.

So why isn't the air warm? If you recall the last setting of the system before it was turned off, was operating the heater.

So even with the system being Off, it's still "on" and adjusting my temperature?

dwest1023

If the car is turn off for only a short time, then you will still feel some heat. The second time you got in the car it sat longer. The water in the system had cooled down and heat register cooled down.Hence cooler air. Thats my take on it.

vinnier6

iTrader: (1)

because the last setting you had was 72, and you said its 80 out now....the air comming in is not being warmed, because you have it set lower then the temp the air is outside...in affect sending the air from outside into the cabin at the same temp as it is outside...when its colder outside, then the temp you have set, the air is goning to be warmed to the set temp even though the system is off...its no different then a 1995 honda, using that as an example...

cabanalane

Therefore, something still has to determine (and measure) if the outside air is warmer or cooler than the set temp. So the system is still "working" even thou it's off?

On a 1995 Honda, or non-electronic system, if you set the dial to half way between red and blue. It will always let in warm air (as long as the engine is hot), regardless what the outside temp is. If outside is cold, it will let in warm air. If outside is hot, it will still let in warm air.

An electronic AC does not do that, when it's off.

Litt

When you are in Starbucks for only a short time in the morning the engine is still warm. It is still cold out so since it is set to 72 it still needs to heat.

When you turn on the car in the afternoon, the engine has completely cooled off. Since it is 8' warmer outside the computer isntantly calculated that it is 95' inside the car, and you want it to be 72 so it better start cooling fast.

It always only going to look at the differential between what it actually is inside, and what your requested internal termperature is.

cabanalane

So it's always on, even when it's off.

vinnier6

iTrader: (1)

your wrong in the way you are thinking about the 95 honda accord....the dial is relative to the temp outside...if you set the dial half way between the red and blue...say for instance, the dead center of the dial is 72 degrees...if its warmer then that outside, its only going to let 72 degree air through the system, if its 30 degrees out, its going to feel alot warmer since its colder outside, if its 90 out, its not going to make the air warmer, its going to come in what the temp is outside, its not going to make it warmer....

all cars have a thermostat, including your tl...

this is how i operate my climate control on a regular basis when its cooler here in dallas....i keep the system off most of the time during cooler times, if i feel too cold, i hit the auto on, bump up the temp a few degrees and then turn it off...if i am too warm, i do the oppisite...when it gets too warm out to handle this operation, i turn it on to auto and set the temp i want....

Bearcat94

Why would you ever turn it "Off"?


Mine ('07) is always on "Auto" and usually 72 - 75 degrees. Normally, I'll just tweak it a degree or two.

If it's especially cold or hot, I'll set it higher (or lower) until the interior temp stablizes. Then back to 75 it goes.

ll_22

I believe the "A/C" button just controls the air compressor, and the heating element is separate and will work based on the temperature setting you select. It is always trying to get the cabin temperature to what you set, it's actually a very good HVAC system IMHO.

Stew4HD

I think the real answer to the OP's question is in bold, above. The car has a thermostat that measures the interior temperature. The temp setting on the control panel that the driver makes is called the 'setpoint'. The electronics will measure the difference between setpoint and what the thermostat measures. If in "auto" mode, then the car will cool or heat to adjust to meet "setpoint"

Temperature is the hardest process to control compared to pressure, level and flow

Eli

The auto climate logic works really well. I set it to 70 degrees when I bought the car 2 and a half years ago and haven't touched it since, through summer and winter. It always does the right thing. It's best not to even think about it.

The only manual setting I'll touch is to force the A/C compressor off when opening a window/moonroof so I don't waste gas.

friesm2000

iTrader: (4)

COMPLETELY different system, but kinda the same in a way though

the 95, actually has a cable hooked directly to the air temp door, which is also hooked to the coolant flow valve for the heater core, so all it really controls is the amount of airflow directed over the heater core, and the amount of the coolant flowing through it (has absolutely no temp input into it)
btw why do you think those knobs break/twist so often, that the dealer actually has them in stock


then with the automatic system (which OP is a better term for it, because a system can still be electronic controlled, but not have the "automatic" features to it)
which for your question OP, i think, the issue you are seeing is the fact of the tempeture differential, between the interiors temp, and what is coming through the vent's (ie: the car is already partially warmed up by the sun, so when you get in, you feel that temp, and when the air flows in, it just does not feel as warm as it did when the interior temp was only 40 degrees



edit: also when you say electronic AC, i think of the Toyota Prius, with a "ELECTRONIC/electric" AC compressor
and a another better term then that would have been "ELECTRONIC HVAC system/controls" if anything

full auto here normally ('03), other then those REALLY cold days, i need to defrost the windshield (which then i push the front defrost buttion [right next to the rear defrost button )
and normally once the windshield is defrosted, it goes on the floor/windshield one, which is just a matter of pushing "mode" once; then after it warms up outside, it goes back to "full auto"


and normally the temp stays at 69, then if i am cold i put it at 70, or MAYBE even 72 if i am really cold