Since eevryone readily acknowledges that the e/CVT, PSD, alllows the ICE RPM to be pretty much independent of roadspeed and therefore may be increased dramatically if the SOC is TOO low, why is it then so difficult, seemingly, to grasp the idea that the same method might/could be used if more refrigerant pumping volume were required...??

 

At 95 and under the FEH can use the A/C at the optimum opportunity.
Above 95 and the A/C is forced to run in all conditions, weather optimal, or not. And in my 2005 the A/C compressor also runs at Wide Open Throttle too, which many of us were under the impression A/C is cut off at WOT.

This appears not the case in my 2005.
I can be towing a 3200# trailer, up a 7% grade, at 60 MPH, and the car is in open loop, and the MAP is at ambient, and the A/C compressor still runs.

 

The A/C running, compressor clutch engaged at WOT is extremely unusual.....

On the other hand at WOT and HOT outside would be when the batteries most need (require..??) cooling.

 

This does not seem to be true in my experience. If I shut off the A/C, the RPMs immediately drop back to normal, and I can feel that the A/C compressor is not running (change in performance).

I don't know about prior years, but in my 2008 there is a noticeable difference in the way the car drives and the acceleration, not to mention the SGII readings for TPS when the compressor is running (at any time, not just above a certain temperature).

 

The "problem", increased ICE RPM to support higher than normal refrigerant pumping volume on a HOT and sunny day, may only occur if both "masters" must be served, cool the passenger cabin AND the batteries.

 

I don't know how much this is going to help now - and I haven't read the whole thread. I've been gone for work to Osan AFB for the last 3 weeks and just got back.

But between last summer and this year I only notice this issue when the temp hits 100+ in Vegas. In addition when it is very hot (not 90+ like the OP mentioned ) i.e. 108+ it takes a good 15 minutes for the car to cool down enough to even go into EV mode in the afternoons.

This morning at 750am it was 92 degrees on my drive in and my car loved it. From a "cold start" (if you can even call it that) it only takes about 3-4 minutes to get into EV and I got 45+ mpg on my drive into work (no A/C windows down).

This last weekend when I was running errands with temps in the low 100s - no A/C - from a cold start it was only taking 1.5-2 minutes to "warm up" (or cool down).

That said. I do notice this. Whenever the wife is in the car I can't run without the A/C if it's over about 95 unless I want to hear her complain the whole time ... The RPMs are generally at least 2200 upon accleration or even keeping up speed. When I take my foot off the pedal it goes down to 1100 RPMs and then when the accleration pedal is even barely pushed it goes back to at least 2200 RPMs.

Don't know if that helps.

 

Keep in mind also that the higher the outside temp the harder the A/C system must work to achieve the same cooling effect. The Compressor not only saps power from the engine, it saps more & more power for each degree higher.

 

I believe we have covered this ground. If it were simply a matter of the ICE needing more power, that would be understandable, and would manifest as a gradual increase as the compressor worked harder. Instead, there appears to be a definite software cut off (or cut in) point above which the system simply adds 600 RPM or so.

 

And that is very possible.
As I have found the "software" boosts the RPM on the cold end of things also.
Usually, below zero, and for sure at -15 so there is a "setpoint" in there somewhere.

HTH,
-John

 

Lots of "servo" control loops/routines require some level of hysterisis in order to work properly or optimally.

Most modern systems will shut down the A/C if the engine coolant temperature begins to rise too rapidly or just approaches the upper level limit. Disabling the A/C at one temperature and then re-enabling it at a coolant temperature 15 degrees lower and/or even after a time limit would make perfect sense to me.

Does the Escape have an engine driven coolant pump or electric..?? Engine driven would easily justify revving up the ICE to increase the cooling, coolant flow, if the engine (or battery) is tending toward overheating. In an "ordinary car the A/C would be disabled in this circumstance.