FEH - '09 vs '10

[GaryG]

Hi All

No one has entered a '10 FEH in our Mileage Log to compare the kind of mileage it gets to any of the prior FEH/MMH's. Also, except for Wayne's reviews the FFH is not doing as well as I expected. The change from the 2.3L to the 2.5L was a great improvement in MPG and I know the 2.5L handles E10 much better. Wayne and I are a die hard when it comes to running the A/C and I think this may be the key to the problem. Now that I'm seeing 90's F, I can see condensation dripping from the Aux Battery A/C after parking. I think the heat is improving the efficiency of my engine so the battery A/C is having less of an impact on mileage.

My question is, did the electric A/C take its toll on MPG by robing the HV battery with too much SoC? The 2010's eliminated the Aux battery A/C so cabin A/C is the issue I think. The 2010's also use cabin ventilation now, so does that mean unless the cabin A/C is On the battery will get hotter and be less efficient in hot weather? Running the cabin A/C with all of the other newer electronics can keep the battery SoC below EV levels in city driving is my concern. Was going to an electric A/C compressor before going to a Li Ion plug-in system a bad idea for those people that use the A/C in city driving? Should Ford have stayed with a belt driven A/C compressor until the plug-in change? Any thoughts?

GaryG

[msantos]

Hi Gary;

Do you have a strategy for using your electrically driven AC?

Granted, I do not drive a FEH but the detrimental impact of AC operation can be greatly mitigated in ways that actually work on my Prius or HCH-II. Perhaps foolishly, I am willing to bet that even in the FEH we can make that loss almost negligible as well... in addition to keeping the battery pack healthy and happy.

In my view, a belt driven AC only approaches its "optimal" efficiency when regularly doing a highway routine. On an urban lower-speed regimen, an electric AC is a must in my books. Too bad a fully hybridized AC compressor is not a more common-place feature.

Cheers;

MSantos

[GaryG]

Originally Posted by msantos

Hi Gary;

Do you have a strategy for using your electrically driven AC?

Granted, I do not drive a FEH but the detrimental impact of AC operation can be greatly mitigated in ways that actually work on my Prius or HCH-II. Perhaps foolishly, I am willing to bet that even in the FEH we can make that loss almost negligible as well... in addition to keeping the battery pack healthy and happy.

In my view, a belt driven AC only approaches its "optimal" efficiency when regularly doing a highway routine. On an urban lower-speed regimen, an electric AC is a must in my books. Too bad a fully hybridized AC compressor is not a more common-place feature.

Cheers;

MSantos

The '09 FEH has the last belt driven A/C compressor and Ford changed to the electric compressor starting 2010 in the FEH and FFH. The short test drives I've had in the 2010 FEH and FFH were without the A/C being On so I really don't have any strategy in city driving other than leaving it Off.

My experience with the BMW X6 Hybrid was the camera man requested running the electric compressor A/C in City driving and that was a nightmare. There was not enough charging during P&G because as the A/C was running during an EV glide and the HV battery took a SoC dive. In a short distance the battery SoC was so low the engine would not shutdown for EV. Any amount of EV driving at a steady state speed compounded the problem maintaining enough SoC above EV minimum for any kind of P&G.

Sean mentioned to a new FFH member here not to use the battery for EV like many here that use that strategy in the Prius and Honda's. The reasoning is charging the battery SoC back up with the engine and generator is bad for overall MPG. That may be the best strategy for the Prius and Honda's, but I don't see that as an issue in the '09 and older FEH. I can run the belt driven A/C and burn the battery down in EV and still keep enough SoC with Pulse and EV glide to build the battery back up again for more steady state speed in EV again. I don't think this is a issue in the 2010 FEH and FFH if you don't run the electric A/C compressor, but if you do you can't manage much EV driving and it will be hard to maintain SoC in City driving. This was my point in this thread, City driving with the belt driven A/C is more efficient than City driving with an electric compressor with the cabin A/C running. Even in the hot heat I'm getting around Jupiter FL. my A/C compressor runs to cool the HV battery as soon as the engine restarts for a pulse. I can still get a 70mpg RT on E10 in my '09 FEH in hot weather. If I run the cabin A/C in city driving, I can still build the battery SoC and do P&G with an EV glide as well as some steady state EV driving with my belt driven compressor. I'm not sure this is possible in the 2010 FEH and FFH with an electric compressor.

GaryG

[msantos]

Indeed. A setup consisting exclusively of an electric AC compressor is not without its challenges, especially from an operational standpoint and when the demands are high.

However, one advantage of these electrically driven systems is that most are not inherently binary in that they are either ON or OFF. And in the end, the true impact is often determined by the use and settings strategy one employs. This is the strategy I was sort of referring to.

In other words, instead of cranking the climate control to the most comfortable setting from the onset and draining the pack in a hurry, would a more strategic use help in the case the FEH, such as starting with the highest temp setting then slowly dialing it down a degree at time until occupant comfort is reached? In my experience, this approach produces reasonably good results with minimal impact on the FE and on the heat management requirements of the pack.

Cheers;

MSantos

[Right Lane Cruiser]

Interesting. When run moderately the AC does not seem to drag down the SoC nearly as fast as I had anticipated it would in the FFH. On the other hand, even with it off I really don't seem to get much in the way of charging during a pulse in that car because it doesn't take much at all to pull assist. I have used the charge on pulse method in both the Prius and Debbie's '05 Escape though, so I'm familiar with the technique.

Do you find the charge affinity goes up with your AC on, Gary?

[GaryG]

Originally Posted by Right Lane Cruiser

Interesting. When run moderately the AC does not seem to drag down the SoC nearly as fast as I had anticipated it would in the FFH. On the other hand, even with it off I really don't seem to get much in the way of charging during a pulse in that car because it doesn't take much at all to pull assist. I have used the charge on pulse method in both the Prius and Debbie's '05 Escape though, so I'm familiar with the technique.

Do you find the charge affinity goes up with your AC on, Gary?

There is more of a load on the engine with the A/C On and therefore Assist is that much closer and charging is further reduced. In the FEH you get Assist at 100% engine Load so the generator stops charging the battery at that point. In my '05 FEH it is much harder to stay out of Assist while pulsing on straight gas and even much harder on E10. Due to this, I learned to pulse much slower at a reduced amount of MPG. My '09 FEH can pulse much faster even with the A/C compressor On and still get plenty of charging without using Assist. Also, keeping the battery SoC below 46% the battery will take a faster charge than a fuller SoC. I constantly control my charge needle with RPM and Instant MPG during the pulse to get that rise in SoC after every pulse. I'm now maximizing charging throughout my pulse and reducing engine On time with acceleration. With a steady climb in SoC during P&G, I get that bonus of a steady state speed in EV with the CC On after about 4-6 straight P&G segments. I am now trying to not let my SoC drop below 43.5% after an EV segment and final glide to begin straight P&G to build my SoC again between 45 - 46%.

Sean, if you know of a better way to maximize MPG in your FFH with the A/C Off, please let me know. How do you maintain SoC in city driving with the cabin A/C On?

GaryG

[Right Lane Cruiser]

Thanks for the description, Gary. From your earlier wording it wasn't clear if perhaps the AC being on in your FEH actually encouraged the vehicle to build SoC under certain conditions.

I actually haven't had as much seat time in the FFH as I'd like so I don't have any crystallized thoughts on the best approaches and I haven't had any city driving with the AC on at all. I've been mostly trying to let my wife "bond" with the car so that it is clear it is really hers and there is a lot for her to enjoy in it. I do notice that her SoC stays up fine in the city with AC on, but that's only because she does a lot of braking.

I've had some nice segments with the AC off but they've all been of the "avoid more than a few feet of EV" variety. I have noticed that I can get some charging if I modulate the pedal a bit while accelerating, but those are almost like micro-regens. It doesn't seem to behave the way I recall the Prius and FEH responding to a low intensity pulse. Perhaps the SoC wasn't low enough? Any pulse has to be pretty low power to avoid assist and I haven't yet found anything much off of steady state that will charge...

I tend to pulse right at the limit of power before assist kicks in, then drop back on the pedal enough to switch to EV and immediately pop the shifter into neutral as soon as the engine stops. I've been trying EV only from 0-15mph when starting from a stop but haven't had enough time yet to see if that is an ideal speed to balance SoC usage and engine torque.

Any idea if there is a "Warp Stealth" mode for the Ford Hybrids? I haven't attempted to find one yet and have only driven the car on the highway once.

I may have another opportunity to "play" tomorrow night... we'll see if she'll let me take her car over the 36mi RT.

[GaryG]

Sean, one thing I've learned with the 2.5L and EV mode is it's more efficient to accelerate with the engine and use EV mode for gliding and a steady state speed. This is not the case with my '05 2.3L and EV mode from 0 - up to ~30mph. The '05 has a weak EV mode after 30mph where the '09 can hold 40mph in a headwind. Still, if I'm at 30mph in EV in my '09, I kick the engine On with Carl's accelerator blip and increase my speed if I need too. Once I kick the engine On, I go to the pulse with charging the battery till I get to my target speed. Unless I'm going to stay in EV at parking lot speeds I kick the engine On to accelerate over ~5mph.

I don't understand "Warp Stealth" and Wayne has said the FFH cannot do it so I'll leave it at that. When I do P&G above EV speed I use fuel-cut in "D" till 40mph and shift to "N" when I go EV at 40mph to continue a glide. The FEH will not do fuel-cut in "N" and there is not much if any regen in "D" during fuel-cut. If the SoC is below 46% you must tap the brake pedal to get fuel-cut as Rick and I discovered here at CMPG with our '09 FEH's.

Where I ran into trouble in the BMW X6 Hybrid was not getting any regen shifting to "N". If your wife is staying in "D" while decelerating she is getting regen in city driving with the A/C On in EV. What I'm saying is, with the electric compressor running I don't think you can maintain the SoC with the standard Pulse and glide in EV when you shift to "N" for the glide.

GaryG

[Right Lane Cruiser]

Hi, Gary -- she doesn't fool with N at all. I believe you are right about not replenishing SoC otherwise.

Accelerating from 5mph up with the engine on is pretty much what I had settled on before trying the 0-15mph EV acceleration -- good to know that is the better approach.

Warp Stealth is a mode in Toyota hybrids which is above normal EV range but still uses electric power with the engine injectors off, though the engine is still spinning so it uses a good bit of power. It is like fuel cut but counteracting much (all?) of the engine braking with electrical power. I thought I recalled it didn't exist in Ford hybrids but wasn't sure... thanks for verifying!

[GaryG]

Your wife is like my wife and she would never shift to "N".

One last thing that I thought about that may be the reason you see very little charging during your pulse in the FFH is this. When I first got my '05 FEH, I would get a full charge and then go EV for a complete discharge over and over. With that first SG that I ended up gaving you, I learned how a low SoC would charge so much faster but the Instant MPG would start at ~20mpg and increase as the SoC got higher. Near a full Soc the Instant MPG would read ~38mpg at 30mph with the CC On. My strategy became to keep the SoC low for a faster charge and get back to EV as soon as possible over and over. I think the reason I'm getting more of a charge during my pulse in the '09 FEH is because I'm at a lower SoC always. You on the other hand don't let your SoC get that low and your not going to see the heavy charging during your pulse. My goal is to stuff the SoC in the battery and pulse as fast as I can without Assist. I use to drain my '09 battery to almost a restart (40%) and slowly pulse building my SoC just back to EV range (42%), go EV right away and then finish with a glide in "N" till I'm near a restart again. As I learned to operate with a higher SoC and pulse much faster over and over building SoC to 45 - 46%, this new P&G brought my tanks from 53 to 57mpg averages. If I need to increase my speed over EV range I always have room to continue charging but at a slower rate as the SoC builds.

GaryG