2009 Hot Weather High RPMs?
#91
Re: 2009 Hot Weather High RPMs?
On a side note: I did just post my best tank so far in the 2009 FEH: 39.5mpg over 433 miles! This included 2 very good days (for me) of 40.5mpg for 56 miles and 40mpg for 59 miles as measured on the SGII. Mostly highway, back and forth from work. On the current tank I'm at 40mpg and got 45mpg on the ~30 mile trip into work yesterday.
-- Rick
Last edited by rmcmast; 07-16-2009 at 04:42 PM.
#92
Re: 2009 Hot Weather High RPMs?
We recently took a 120 mile trip (each way) @ 60mph for 99% of the drive. Everything is relatively flat here and we used cruise control.
86 degrees on the way up, climate control set to 77 and we achieved an actual (refill) of 40.3 normal low rpm mode.
94 degrees on the way home, same route (reversed) 60mph, cruise set, climate control set at 77 and we achieved an actual (refill) of 36.1 higher rev rpm mode.
If you read what you quoted from my other post, I didn't type that you couldn't increase mpgs with less pressure, I typed that the rpms were stuck @ 2k.
I agree that ANY vehicle can increase mpg significantly with lighter pedal pressure. You won't be able to match the mpg in the 2k rpm mode with the regular (lower) rpm however...
We are going to be making the same trip this weekend. We are going to leave early in the morning, so I am going to try and match the 40- on the way up @ 60mph again.
86 degrees on the way up, climate control set to 77 and we achieved an actual (refill) of 40.3 normal low rpm mode.
94 degrees on the way home, same route (reversed) 60mph, cruise set, climate control set at 77 and we achieved an actual (refill) of 36.1 higher rev rpm mode.
If you read what you quoted from my other post, I didn't type that you couldn't increase mpgs with less pressure, I typed that the rpms were stuck @ 2k.
I agree that ANY vehicle can increase mpg significantly with lighter pedal pressure. You won't be able to match the mpg in the 2k rpm mode with the regular (lower) rpm however...
We are going to be making the same trip this weekend. We are going to leave early in the morning, so I am going to try and match the 40- on the way up @ 60mph again.
#93
Re: 2009 Hot Weather High RPMs?
If you read what you quoted from my other post, I didn't type that you couldn't increase mpgs with less pressure, I typed that the rpms were stuck @ 2k.
I agree that ANY vehicle can increase mpg significantly with lighter pedal pressure. You won't be able to match the mpg in the 2k rpm mode with the regular (lower) rpm however...
I agree that ANY vehicle can increase mpg significantly with lighter pedal pressure. You won't be able to match the mpg in the 2k rpm mode with the regular (lower) rpm however...
I agree that we won't be able to match the mpg we can get with lower rpm.
-- Rick
#94
Re: 2009 Hot Weather High RPMs?
Steve,
I have been fooling around to find out why the 09 does this. I can tell you that it is costing about 4mpg on the highway for sure. Around the city could be even more detrimental.
Here are some things I have discovered on MY 09feh:
It has to be over 91 degrees outside temp.
When it is behaving this way, the only way to get the rpms to drop back to normal is to shut the a/c button off.
"..shut the A/C button off..."
Does this disable the A/C compressor entirely or does it still run at low volume, lower engine RPM, only to keep the batteries cooled..??
When the A/C is on, there is no throttle position other than idle that will allow the engine to drop below 2000 rpm.
The amount of charge in the battery (using the primitive nav gauge) does not make a difference.
The amount of charge, SOC, wouldn't be of interest insofar as the need to cool the batteries, that would be primarily a function of the discharge or recharge rate plus some extra cooldown period after.
Sorry, the above statement is probably wrong. Even the shelf like of some batteries will be reduced if stored at higher temperatures. Your hybrid batteries may need to be cooled FULL TIME, "in service time", if the incoming FRESH airflow is above some design temperature.
The inside adjustable temp does not matter, regardless if it's set to 60 or 90.
Yes, if the A/C is enabled for cabin cooling, or by default wintertime dehumidifcation purposes, the cabin temperature setting would have virtually no effect since the temperature of air outlet flow to the cabin is a function of the reheat/remix blend door/vane position.
Manual inside fan settings, auto temp, recirc, econ buttons have no effect on the behavior.
It never does the high rpm until after at least 20 minutes of driving.
Once it starts with the behavior it does not stop unless you shut off the a/c
A caviat to this is, at certain times I can see the truck TRY to come out of this mode and the rpms will drop to 1300 or so, but one or two seconds later and it's right back up to 2000 rpm.
Today when I got home from an irritating 2000 rpm drive, I got under the truck and one of the a/c lines running to the rear battery was cold.
On a side note, it makes me wonder why the A/C lines running to the rear aren't insulated in any way....
And the answer was..??
Our 2008 FEH NEVER did this. The beauty of that truck was, as long as the engine was running, the a/c was nice and cold, even at lower rpms.
With the 2009, you are now stuck at 2000 rpms, even with the slightest of pedal pressure, even at 41mph and that sucks.
There are many many reasons I wish I had just kept the 2008, this is just one.
Sean
that's all I have for now, anybody have anything to add??
I have been fooling around to find out why the 09 does this. I can tell you that it is costing about 4mpg on the highway for sure. Around the city could be even more detrimental.
Here are some things I have discovered on MY 09feh:
It has to be over 91 degrees outside temp.
When it is behaving this way, the only way to get the rpms to drop back to normal is to shut the a/c button off.
"..shut the A/C button off..."
Does this disable the A/C compressor entirely or does it still run at low volume, lower engine RPM, only to keep the batteries cooled..??
When the A/C is on, there is no throttle position other than idle that will allow the engine to drop below 2000 rpm.
The amount of charge in the battery (using the primitive nav gauge) does not make a difference.
The amount of charge, SOC, wouldn't be of interest insofar as the need to cool the batteries, that would be primarily a function of the discharge or recharge rate plus some extra cooldown period after.
Sorry, the above statement is probably wrong. Even the shelf like of some batteries will be reduced if stored at higher temperatures. Your hybrid batteries may need to be cooled FULL TIME, "in service time", if the incoming FRESH airflow is above some design temperature.
The inside adjustable temp does not matter, regardless if it's set to 60 or 90.
Yes, if the A/C is enabled for cabin cooling, or by default wintertime dehumidifcation purposes, the cabin temperature setting would have virtually no effect since the temperature of air outlet flow to the cabin is a function of the reheat/remix blend door/vane position.
Manual inside fan settings, auto temp, recirc, econ buttons have no effect on the behavior.
It never does the high rpm until after at least 20 minutes of driving.
Once it starts with the behavior it does not stop unless you shut off the a/c
A caviat to this is, at certain times I can see the truck TRY to come out of this mode and the rpms will drop to 1300 or so, but one or two seconds later and it's right back up to 2000 rpm.
Today when I got home from an irritating 2000 rpm drive, I got under the truck and one of the a/c lines running to the rear battery was cold.
On a side note, it makes me wonder why the A/C lines running to the rear aren't insulated in any way....
And the answer was..??
Our 2008 FEH NEVER did this. The beauty of that truck was, as long as the engine was running, the a/c was nice and cold, even at lower rpms.
With the 2009, you are now stuck at 2000 rpms, even with the slightest of pedal pressure, even at 41mph and that sucks.
There are many many reasons I wish I had just kept the 2008, this is just one.
Sean
that's all I have for now, anybody have anything to add??
Do you realize this may be a fix for a flaw in the earlier, 2008, design. Keeping the batteries "better" cooled would likely extend their service life.
Last edited by wwest; 07-16-2009 at 07:28 PM.
#95
Re: 2009 Hot Weather High RPMs?
While the Cabin A/C efficiency can be improved via recirculation of previously cooled airflow I doubt that the battery compartment could use that technique. So the batteries must be cooled using FRESH airflow that comes into the system at ~95F.
#96
Re: 2009 Hot Weather High RPMs?
That is another incorrect statement about the newest Hybrid Ford system.
#97
Re: 2009 Hot Weather High RPMs?
Hi, first post to the group. Saw the same issue with my 2009 FEH the other day. Temp was in the mid 90's and I looked down at the tach and it was at 2500 at steady 60MPH. I toggled the AC on and off and the RPMs toggled with the setting. About a minute later the condition stopped. I need to get a ScanGauge so I can monitor what conditions cause the behavior...RayP
#98
Re: 2009 Hot Weather High RPMs?
Ray,
Let us know what info you can get from the scan gauge when this is happening. (bat temp etc.)
WWest, that is a good idea and I will check next time to see if the compressor is still running after I shut off the interior a/c button.
On that note, I wonder if the rpms ONLY go up when the compressor is doing double duty. By double duty I mean cooling the cabin AND the battery...
Perhaps the double duty is why the higher rpms are needed to cool the battery and the cabin effectively.
I also agree with WWest that it is possible FMC wanted the batteries even cooler in the 09 for some reason, so they run the a/c to the rear at either any outside temp above 91 OR at a lower battery temp..
I really am interested in learning if the rpms come up only when the compressor is cooling both the cabin and the battery pack tho.....
Sean
Let us know what info you can get from the scan gauge when this is happening. (bat temp etc.)
WWest, that is a good idea and I will check next time to see if the compressor is still running after I shut off the interior a/c button.
On that note, I wonder if the rpms ONLY go up when the compressor is doing double duty. By double duty I mean cooling the cabin AND the battery...
Perhaps the double duty is why the higher rpms are needed to cool the battery and the cabin effectively.
I also agree with WWest that it is possible FMC wanted the batteries even cooler in the 09 for some reason, so they run the a/c to the rear at either any outside temp above 91 OR at a lower battery temp..
I really am interested in learning if the rpms come up only when the compressor is cooling both the cabin and the battery pack tho.....
Sean
#99
Re: 2009 Hot Weather High RPMs?
As for the freon line being not insulated, I don't think it matters.
The "cold" line is the return line going back to the compressor under the hood.
So no "coldness" is "wasted" going to the pack.
When freon is compressed, it is actually hot, not cold, and liquid.
The hot high pressure line goes into the pack's "evaporator" where the pressure is lowered, the liquid vaporizes, and the freon cools dramatically.
The cold line is vapor going back to be liquified again.
Insulation may add little effect, at additional cost.