Efficiency on longer highway trips...

[md13ffhguy]

Yes and yes!

 

1. Let the car do it's magic on the highway and enjoy the ride!

 

2. With out the load of charging the HVB you can see 50+ on flat road @ 65 MPH. This is basically what happens when the HVB is near "full" charge and the ICE propels only the car and not any longer the generator on top of it.

Ahhh! So, it takes a flat road! I've tried this several times and can never really make it happen for more than a few seconds. Too many ups and downs on the highways around me. EV cycling for me on my roads.

[hybridbear]

What you achieve with this technique is you basically drive the FFH powertrain to behave like a Toyota HSD powertrain.

 

The Prius would go as low as 4 HP on the freeway with the instant MPG at 100+. The Camry is similar. The FFH won't go lower than about 15 HP but if you're on the freeway just barely keeping the ICE on with your foot then the FFH will run the ICE at 15 HP and will use almost all of that power to charge the HVB while still getting 50+ instant MPG.

 

Larry_h has done calculations to show why this is more efficient than letting the car cycle itself. Since he has an Energi & can track MPGe in EV mode he has been able to do this.

[hybridbear]

Ahhh! So, it takes a flat road! I've tried this several times and can never really make it happen for more than a few seconds. Too many ups and downs on the highways around me. EV cycling for me on my roads.

I do it on the rolling hills of MN. I set my cruise at 65 MPH for example when the speed limit is 70 & then I will gently press the gas pedal just enough to prevent the car from going into EV mode. On downhill stretches I often speed up to 70+ and then I gradually slow down going up hill until the cruise control kicks back in just above 65 MPH.

[darrelld]

I used no special driving techniques to achieve 38 hand calculated mpg at 75 mph. I just set the upper limit of radar eco cruise to 75 mph and let the cruise control the rest. The only time I touched the brake was exiting to get coffee at McDonalds.

[acdii]

The previous generation Fusion was very efficient at highway speeds. The ICE in that car is great for highway cruises, and in the non Hybrid with the same Non Atkinson Cycle is showing good Highway too. I got up to 65 MPG on the interstate in my 2010. I will not see the same in the 13 because the ICE is only 2.0 and not the 2.5 as in the 1st gen. It needs EV assist to make up for the difference in displacement, but using as little EV as possible above 45 MPH appears to be the key. Even using just a little bit will force the ICE back to generator mode and you will see instant cut in half.

[lolder]

Ford ought to undo the software update that raised the maximum EV speed to 86 mph. It didn't help and made things worse in some situations.

[hybridbear]

Ford ought to undo the software update that raised the maximum EV speed to 86 mph. It didn't help and made things worse in some situations.

I disagree. It helps in some situations, such as when you are going down a mountain. And once you get up to about 70 MPH the threshold bar on the empower screen gets very small which makes it hard to get the ICE to turn off. The improvement I would suggest is making the threshold bar to turn off the ICE get small at lower speeds. However, being able to turn off the ICE when descending a mountain at 65+ MPH is helpful because it means you can get more regen without friction losses going to an ICE that's spinning with no fuel being injected.

[lolder]

I see your point but I am doubtful. The amount of regen you can store is solely related to how much headroom you have in the HVB before it's full. I think they use very little energy spinning the ICE to meet maximum Gen speeds. Your instantaneous mpgs go way high in those circumstances. I think they were grasping at straws when they upped the EV speed. There is also an energy penalty when you start the ICE as that's a significant brief amount. Ford probably starts and stops 10 times as often as Toyota and Toyota still leads the pack, mostly because they're lighter, sleeker and less powerful. Does anyone have data that shows the software update improved any area of driving?

Edited July 17, 2014 by lolder

[hermans]

Ford ought to undo the software update that raised the maximum EV speed to 86 mph. It didn't help and made things worse in some situations.

Not in my case. When the update was done in my car I started noticing increased mileage. I live in PA. Lots of hills and then mountains when I travel. Right now I'm at 44.6.

[lolder]

Not in my case. When the update was done in my car I started noticing increased mileage. I live in PA. Lots of hills and then mountains when I travel. Right now I'm at 44.6.

When did the update occur? Seasonal temperature is a very large effect. The next biggest effect is driving habit change. You have to factor them out. They didn't change the weight, horsepower or drag Cd. They only increased EV use at higher speeds. That is generally the wrong thing to do with hybrids. EV use at higher speeds is inefficient, even with an improved LiIon HVB. It may have slightly benefited very hilly driving at the expense of flatland driving. The only way it could have helped is if it moved a significant larger portion of the ICE operating time into a lower BSFC area on the fuel map of the ICE. It would have to be a significant improvement because of the EV cycle losses.

Edited July 17, 2014 by lolder

[hermans]

The upgrade was done the week after it was announced. I'm aware of the seasonal differences. I took delivery on 12/4/2012.

[Waldo]

EV use at higher speeds is inefficient, even with an improved LiIon HVB. It may have slightly benefited very hilly driving at the expense of flatland driving. The only way it could have helped is if it moved a significant larger portion of the ICE operating time into a lower BSFC area on the fuel map of the ICE. It would have to be a significant improvement because of the EV cycle losses.

 

I think this is the key. It seems to me that our aero/rolling resistant vehicle would not generate enough load cruising along on flat ground at even 65mph to bump the engine's operation into the efficient BSFC zone (this might not be true of Toyotas and their smaller engines). If the extra load of charging increases the BSFC by more than the charge/discharge loses, it makes sense to cycle through EV mode at higher speeds. I trust the Ford engineers who actually have access to this data to make the right decisions. Since the EPA label didn't change with the software update, we know they didn't do it just to plays games with the EPA cycle testing.

 

Driving with the ICE on and getting 50mpg over ten miles burns just as much fuel as driving with the ICE on at 40mpg for 8 miles and EV mode for the other 2 miles. That's why the instant fuel economy reading doesn't really tell the whole story.

Edited July 17, 2014 by Waldo

[hybridbear]

I think this is the key. It seems to me that our aero/rolling resistant vehicle would not generate enough load cruising along on flat ground at even 65mph to bump the engine's operation into the efficient BSFC zone (this might not be true of Toyotas and their smaller engines). If the extra load of charging increases the BSFC by more than the charge/discharge loses, it makes sense to cycle through EV mode at higher speeds. I trust the Ford engineers who actually have access to this data to make the right decisions. Since the EPA label didn't change with the software update, we know they didn't do it just to plays games with the EPA cycle testing.

 

Driving with the ICE on and getting 50mpg over ten miles burns just as much fuel as driving with the ICE on at 40mpg for 8 miles and EV mode for the other 2 miles. That's why the instant fuel economy reading doesn't really tell the whole story.

This is true and I also trust the Ford engineers. They also changed more than just the EV speed. To do that they had to change the code that affects how the car behaves at more than just those high speeds. They also changed the programming when the ICE is cold and the programming for grille shutters.

 

The issue is I don't think you can do what you propose in your comparison. You could do 10 miles @ 40 MPG of ICE only or 6 miles at 24 MPG and 4 miles of EV. The problem is that at freeway speeds you can't do much more than 40% EV even with rolling hills and those 6 miles with the ICE on would likely be less than 24 MPG.

[Waldo]

The issue is I don't think you can do what you propose in your comparison. You could do 10 miles @ 40 MPG of ICE only or 6 miles at 24 MPG and 4 miles of EV. The problem is that at freeway speeds you can't do much more than 40% EV even with rolling hills and those 6 miles with the ICE on would likely be less than 24 MPG.

 

Show me the data! The logic would support either hypothesis in this case, it's only with real data that we can make useful conclusions. Otherwise we're just guessing.

[hybridbear]

 

Show me the data! The logic would support either hypothesis in this case, it's only with real data that we can make useful conclusions. Otherwise we're just guessing.

Larry_h did already.

[talmy]

What you achieve with this technique is you basically drive the FFH powertrain to behave like a Toyota HSD powertrain.

 

Larry_h has done calculations to show why this is more efficient than letting the car cycle itself. Since he has an Energi & can track MPGe in EV mode he has been able to do this.

 

This is some craziness! In a Toyota you try to get it to behave like a Ford (forcing it to cycle in and out of EV mode*) for best MPG. And in a Ford you try to get it to behave like a Toyota (keeping the ICE running) for best MPG. Since I've got both, it's confusing! Somehow I'd think Ford and Toyota both know what's best for their respective designs.

 

* Well published Toyota hypermiling technique is to speed up to 42 (maximum speed for EV) release the accelerator to let it enter EV mode and maintain a light touch just less than what will restart the ICE -- this takes practice since there are no gauges for this -- speed falls and charge drops. At some minimum speed, with angry drivers to the rear piling up, you accelerate back to speed letting the battery recharge. Repeat. At least the Ford maintains the speed on EV, reducing the number of angry drivers.

 

I don't find the fussing around worth the effort with either. Just drive them reasonably and they both produce good results. And to find out how well any technique works requires making two round trips, one with the technique and one without, with all other conditions (traffic, weather, accessory use, ...) the same.

[lolder]

I trusted the Ford engineers until they said they made an honest "mistake" in rating the cars at 47 mpg. That's preposterous !!! You don't make mistakes like that. Did any body get fired? Not that we know of. They knew of the problem when they went for the reprogramming hoping they wouldn't have to own up to the "mistake". I love my 2010 and the 2013+ are properly rated at 42 and are nice cars. Ford tried to put one over on Toyota and failed. Just my opinion.

[Ram]

I trusted the Ford engineers until they said they made an honest "mistake" in rating the cars at 47 mpg. That's preposterous !!! You don't make mistakes like that. Did any body get fired? Not that we know of. They knew of the problem when they went for the reprogramming hoping they wouldn't have to own up to the "mistake". I love my 2010 and the 2013+ are properly rated at 42 and are nice cars. Ford tried to put one over on Toyota and failed. Just my opinion.

 

What he said.

 

I drive this Ruby Red color car that I love the color day in and day out full well knowing that my secondary reason for purchasing it was on the sticker - 47/47/47.

 

Every day that I own this car, it will be known to be the car of lower expectations, not only to me, but to the entire world.

And Ford will so graciously give us a one time payment for our troubles.

 

Ford should pay me daily for my troubles, this car is the first thing that I look at everyday when I walk out my front door to go to work. Its parked right next to my '99 Chrysler Sebring Convertible that has over 226K miles on the clock and I wanted a car that gets double the mileage over my vert. I wanted to keep from wearing my vert flat out with the mileage that I put on the thing. The third thing was I wanted to stop working on the vert when my cancer is killing me. Which up until getting the FFH was my daily driver.

 

The FFH gets more than double (more like triple) miles per gallon period over my '86 Dodge Ramcharger Royal SE 4x4, and double to my '10 Chrysler Town & Country (Van). But not near close to my '06 H-D FLHRI (actually gets better than the FFH). I don't drive them on a daily basis either.

 

Notice that I'm careful not to mention a thing about the EPA. I don't want to be called a fool in the politest terms again by some near do well for me not knowing Shine-Ola about the EPA.

 

I'm still pissed over the Ford mistake.

 

Have you seen the you-tube video of the 2013 auto show some Ford high up auto exec or rep had toughed this new Ford Fusion Hybrid as being what Ford is hanging their hat on for the future with this mileage. And the you-tube video with all the hours on top of hours of wind tunnel testing of this body design to get this fuel efficiency. No I don't have either link, they are on you-tube and not hard to fine if you do a search like I did over a month ago.

 

This is why Ford does not make areo space craft. Can you imagine the crew members, going to the Moon or going to Mars and not being able to make it? Oh, we made a mistake, you have to turn around and come back now.

 

These are just cars.

 

Rant off, have to go take more med's.

 

Sorry for steeling the post. Back to normal posting of the OP now.

Edited July 18, 2014 by Ram

[lolder]

Ford has been doing very well under recently retired Mulally. I think the C-Max sales have taken a big hit since the down grade and it became clear that it didn't get better mileage than the Prius V and actually was 10 mpg worse in the real world. That's a big hit in the pocket book. Sometimes these things are created by Marketing who dictates what the car has to do. Kind of like the "Weapons of mass destruction" PR.

Mulally has taken a position on Google's Board. People have been wondering who is going to build their autonomous vehicle. Is this a clue?

[md13ffhguy]

+1 to letting the car do its thing as the engineers intended. I believe the "technique" discussed here is possible and probably viable in the right circumstances. However, with the traffic conditions I face, I can't seem to get it right, so I feel it's not worth my effort. I really don't think I could improve much on my mileage anyhow.

[larryh]

Based on my observations, when the ICE is providing between 20 to 35 kW of power, efficiency is around 35%. Of the 33.705 kWh of energy released from the combustion of a gallon of gas, 35% of this energy is converted to mechanical energy used to power the car and charge the HVB. When the power provided by the ICE is less than 20 kW, efficiency starts to fall. For example, when providing 10 kW of power, the efficiency might drop to 25%. (It requires about 20 kW of power to go 65 mph and about 10 kW of power to go 50 mph.)

 

The efficiency the motor/generator in generating electricity is probably around 90%, i.e. 90% of the mechanical energy provided to the motor/generator is converted to electrical energy. The efficiency of the motor/generator in providing mechanical power is about 80%, i.e. 80% of the electrical energy provided to the motor/generator is converted to mechanical energy. This means about 90%*80% = 72% of the mechanical power provided by the ICE to charge the HVB is actually recovered in EV mode.

 

There is little advantage in having the ICE charge the HVB when it is providing 20 kW of power (around 65 mph) or more to propel the car. You are only going to recover 72% of the energy produced by the ICE when in EV mode. So 35% of the energy released from the combustion of gas is converted to mechanical power to power the motor/generator, and then 72% of the resulting electrical energy is converted back to mechanical power to propel the car later in EV mode. The overall utilization efficiency of this portion of the gas that was used to charge the HVB and later power the car later in EV mode is then 35%*72% = 25%. If you now run the car in EV mode at 65 mph using the energy from this gas, you are now effectively only getting 25% efficiency from the combustion of that gas and have lowered the overall mileage (mpg) of the car. If you had not used the gas to charge the HVB, and instead used it to propel the car, you would be getting 35% efficiency. Charging the HVB and running later in EV mode reduces mileage (mpg) at 65 mph.

 

However, if you could utilize the energy stored in the HVB at a later time when the power required drops below 10 kW and efficiency of the ICE drops below 25%, then it is advantageous to charge the HVB at 65 mph. With the gas used to charge the HVB, you are effectively getting 25% efficiency. If you had instead used the gas to power the ICE and propel the car (without charging the HVB), you would have gotten less than 25% efficiency since ICE efficiency has dropped below 25% at 10 kW of power. This can happen during downgrades on the freeway. So you might want to charge the HVB while driving 65+ mph so you can power the car later in EV mode while driving on a downgrade. (There are additional considerations, such as having the HVB assist the ICE to reduce the load and drive it into a more efficient operating region.)

 

Better yet, is to charge the HVB when the power required to propel the car is less than 20 kW. The additional power required to charge the HVB increases the overall ICE efficiency from maybe 25% to 35%--the ICE is providing 20 kW of power rather than 10 kW of power. So now you are getting 35% efficiency from the gas that is used to propel the car (rather than 25%). In addition, you are going to get at least 25% efficiency from the portion of the gas that was used to charge the HVB. So charging the HVB and running later in EV mode increases mileage (mpg) at slower speeds (around 50 mph or less).

 

The goal is to achieve maximum efficiency for all gas consumed. Don't run in EV mode when high power is required (high speeds or up hill), and don't charge the HVB. Don't run the ICE when low power is required (at low speeds or down hill), unless you can also charge the HVB to increase the load on the ICE and can run later in EV mode at low speeds.

 

There are additional considerations when deciding to charge the HVB. The HVB of the Fusion Energi is composed of 84 cells (less for the Fusion Hybrid). The cells need to all be kept balanced, i.e. maintained at the same SOC and voltage. Using power from the HVB tends to disrupt this balance--the greater the power drawn from the HVB and the lower the SOC, the greater the disruption. Charging the HVB restores the balance. The weaker cells experience greater stress than the stronger cells. If the cells are not rebalanced, the weaker cells will continue to experience more stress until they fail. See the following and subsequent posts:

 

"http://www.fordfusionenergiforum.com/topic/1683-obd-ii-data-for-hvb/?p=14915"

Edited July 18, 2014 by larryh

[acdii]

Well I have been forcing the ICE to run and keep the battery charged up under almost all driving conditions as an experiment, only when speed is under 30 am I on EV, and usually it takes very little energy to stay at 25. So far the ends results are right at 47 MPG. The past few mornings I kept it on ICE going through Crystal Lake where I normally cruise through on almost all EV, and the result is that I lost about 1-2 MPG, but its consistent, sitting at 46 and change both times, however my return trip home which has been pretty bad due to increased traffic and more stop and go has increased. I am seeing 45+ now instead of 41.

 

End result is if you can coast through town with few stops and a somewhat steady speed, EV works best, but if you are in traffic, with speeds that are up and down and multiple stops, staying on ICE with the battery charge high seems to work best. At highway speeds of 60+ keeping the HVB charge high and staying on ICE works best. When traffic is slowing, taking the foot off the pedal and coasting puts energy back in, then when resuming hit the ICE instead of EV. Since acceleration combines EV+ICE, with a full charge once up to speed EV kicks off, and any residual energy from the ICE that isnt used to maintain speed goes back into the battery. I am seeing more and more that my charge/discharge arrows are disappearing which means all ICE energy is used at the wheels, and not being used to charge the pack. This last tank is at 46.9 MPG, however my wife can easily kill the MPG, she is OK driving it, but doesn't have the diligence to drive it like I do. She only seems to get 42 in it, which is right along the lines of the average driver. She drove the first 80 or so miles on this tank, otherwise it would be closer to 48.

 

This car can achieve 47 provided everything is in proper working order and driven just right, which is the most difficult part for most drivers, mainly due to regular cars being just hit gas and go. The hardest part for most people would be avoiding pi$$ing off other drivers by slowing and speeding up, however the Fusion does away with that, as it can maintain a nice steady speed and still get good MPG. I only find myself P&G when traffic dictates it, but when traffic is flowing I am right there with it and still getting 40+ or better MPG instant.

[lolder]

Keeping HVB charge-discharge arrows off is the same as pulse and glide, the maximum hypermiling technique. It's hard to do and requires too much concentration. A hybrid is designed to do 90% of that automatically. It's all about never operating the ICE except in it's maximum thermodynamic efficiency range ( low BSFC ). Plug in hybrids have some different design goals. The operating software is a compromise. I still think upping the EV speed made the compromise worse.

Edited July 18, 2014 by lolder

[hybridbear]

Keeping HVB charge-discharge arrows off is the same as pulse and glide, the maximum hypermiling technique. It's hard to do and requires too much concentration. A hybrid is designed to do 90% of that automatically. It's all about never operating the ICE except in it's maximum thermodynamic efficiency range ( low BSFC ). Plug in hybrids have some different design goals. The operating software is a compromise. I still think upping the EV speed made the compromise worse.

It did & didn't. It depends on the programming. It made things worse if you're driving a lot at 65 MPH as Larry has proved. But it made things better if you're driving at 70+ in the mountains.

[acdii]

Mine is starting to get easier to have 0 HVB energy in/out while cruising. It takes a really light and steady foot, but after a few weeks of driving the way I do now, it has become much easier, and I find myself getting mad(at myself) when it goes into EV. Where I drive I found the most efficient method on the FFH, it may not work for others situations, where the travel is mostly flat, with very few hills, or in slower zones were the average limit is 45 or less. In suburban driving where the roads are mostly 35 and 45 MPH, using more EV where you regenerate at lights gives better MPG than the method I use for my driving. If I lived more towards Chicago, I too would be averaging 50 MPG in the Fusion. For where I live and travel though very pleased with what I am getting. Been driving the same roads now for 13 years to the same area 5 days a week and know what to expect in MPG in any given vehicle, and when I exceed it, very happy with it, and that is holding true for both the Fusion and my MKT, in fact I am Very impressed with what I have been getting in the T. I am exceeding EPA in it. I am exceeding what I got in my first Flex, and I was happy getting the 18.5 it got since it was a 360 HP 420 Footpound beast.