POLL - Actual Computed Mileage

[black70bird]

I have ~325 miles on our car, 50% 65-75 mph with AC, 41.1 mpg for a 54 mile commute that has ~1200' of altitude change. I have been driving a Prius for 7 years so I am hybrid driving style savvy. This far exceeded my expectations due to the size of the FFH. I will be switching back to the Prius after this week and my wife gets her car back. She drives mainly in the city and I drive a 50/50, with some high speed, commute that I think will be a good break in. I am wondering how to extend the break in without being to obvious that I like the car.

 

I have found that the Prius gets considerably lower mileage during the winter in Colorado than in the summer, even running AC. So it will be interesting to see what the FFH does.

 

2010 A502 White Platinum with Charcoal Black, full clear bra (yes bumper too)

[VonoreTn]

Ok...now I'm jealous. I just rolled over 1,500 miles on my FFH and am still on my 4th tank. My average so far is 28.5. So I guess I win the award for lowest possible mileage. Now to clarify, it's been 110 - 115 degrees over the last few weeks so the a/c is on full blast 100% of the time. Even though my mpg is lower than everyone's, it is still double my last car so I'm very pleased. I can only assume that when summer ends, my mpg will increase dramatically.

 

My experience working at Ford as an engineer in accessory drive, air conditioning and engine tells me that you can be using 6 hp of power at the compressor, running your air conditioner on a day as you describe, 110F. Since it only takes about 8 hp to keep a Taurus running without AC at 40 mph on a flat road, and 15 hp at 60 mph, it is easy to see that a car air conditioner load will be in the same magnitude range as keeping the car moving. Now you add the inefficiency of running the air conditioner compressor with an electric motor instead of directly off the engine, and you have some serious parasitic loss. I'd say be grateful for the cold air and the 29 mpg, and hope for cooler weather.

[Oman]

My understanding is that the variable speed electric compressor actually draws less power from the hybrid system than if it was mechanically connected. This is mainly because the high-voltage system is already in-place for the drive components. The real question is how long are your driving segments? The most power is used for the initial cabin cool-down and engine warm-up. If your drives are short then you will see this mileage continue.

 

 

VonoreTn:

I know that 15 hp is the "gold standard" used in engineering for a compact car with good aerodynamics, but I don't know how big a compact car is when used for this formula. I would assume that a Fusion and Taurus would be more of a midsize. I've been trying to make the conversion from Amp Hours on the parasitic load side to hp on the ICE since all the energy comes from the ICE whether direct or reclaimed but it isn't that easy given all the variables.

 

Jon

 

 

 

My experience working at Ford as an engineer in accessory drive, air conditioning and engine tells me that you can be using 6 hp of power at the compressor, running your air conditioner on a day as you describe, 110F. Since it only takes about 8 hp to keep a Taurus running without AC at 40 mph on a flat road, and 15 hp at 60 mph, it is easy to see that a car air conditioner load will be in the same magnitude range as keeping the car moving. Now you add the inefficiency of running the air conditioner compressor with an electric motor instead of directly off the engine, and you have some serious parasitic loss. I'd say be grateful for the cold air and the 29 mpg, and hope for cooler weather.

[GreenGene]

My in-town driving is mostly stop-go-stop-go and usually less than a mile. If I get onto the freeway I can hit 37mpg. There's a lot of red lights here (every couple of blocks) and I barely get up to the speed limit before having to stop again. But again, I'm not complaining because my current mpg is double that of my last car. So I'm still way ahead. I'm just curious to see what happens when things cool off. The way I see it, this should be the worst mileage I get and it can only go up from here.

[Oman]

Unfortunately it sounds like your drive is considerably worse for mileage than the EPA test methodology for calculating city MPG:

 

The simple version of the EPA city test:

"The car or truck is driven for 11 miles and makes 23 stops over the course of 31 minutes, with an average speed of 20 mph and a top speed of 56 mph."

 

An average speed of 20 mph is very hard to obtain if you are only going a block or two between stop lights. Lots of people get ticked off when their city mileage does not equal what the EPA and thus the mfgr claims. The problem is that the definition of city driving varies considerably. The same is true for highway. Aerodynamic drag increasing exponentially to the speed of travel.

 

Jon

 

 

 

My in-town driving is mostly stop-go-stop-go and usually less than a mile. If I get onto the freeway I can hit 37mpg. There's a lot of red lights here (every couple of blocks) and I barely get up to the speed limit before having to stop again. But again, I'm not complaining because my current mpg is double that of my last car. So I'm still way ahead. I'm just curious to see what happens when things cool off. The way I see it, this should be the worst mileage I get and it can only go up from here.

[VonoreTn]

Jon,

 

I should have clarified that the 8 and 15 hp were the numbers we dialed into a windtunnel AC test as to how much drag to put into the drive wheel rolls. So it would be just the HP used to hold 40 and 60 mph, not including the engine HP used to drive the waterpump, alternator, powersteering pump, and the AC compressor. Also not including the driveline loss between the engine and the wheels. And of course not including the 70% of the engine energy that goes to heat, most of which is dumped to the air through the radiator.

 

One advantage the FFH has it it's electric power steering. Almost all hydraulic steering systems have belt driven pumps that run at a minimum of 60 to 100 psi, even when no steering manuevers are occuring. The torque on the pumps to maintain this pressure is a total waste, a true parasitic loss. It didn't used to be that high in the 70's with the old linkage PS systems. It's a bad way to get the stiff on center feel that everyone wants with a rack and pinion PS system.

 

 

My understanding is that the variable speed electric compressor actually draws less power from the hybrid system than if it was mechanically connected. This is mainly because the high-voltage system is already in-place for the drive components. The real question is how long are your driving segments? The most power is used for the initial cabin cool-down and engine warm-up. If your drives are short then you will see this mileage continue.

 

 

VonoreTn:

I know that 15 hp is the "gold standard" used in engineering for a compact car with good aerodynamics, but I don't know how big a compact car is when used for this formula. I would assume that a Fusion and Taurus would be more of a midsize. I've been trying to make the conversion from Amp Hours on the parasitic load side to hp on the ICE since all the energy comes from the ICE whether direct or reclaimed but it isn't that easy given all the variables.

 

Jon

[mirak]

I've only driven about 120 miles so far, and I'm less than a quarter of the way through the dealer's first tank of gas, so I can't provide a very accurate mpg.

 

I'm mainly doing short city commutes to/from work, at about 5 miles per trip, so my mileage probably is not as high as it could be. The computer says that my trips are ranging from mid 30s to mid 40s, but mostly around 41 or 42. 46.1 was the highest I've racked up so far.

 

I'm not sure how the computer calculates overall average mpg, but it is strange. I think this value started in the teens, and has slowly crept up from there. After 120 miles, I'm now up to 34mpg, even though every single-trip average has exceeded that. I wonder why it takes a while for the overal average to "catch up?" It's like I'm being averaged against some zeros, or something.

[VonoreTn]

That number will continue to get better as you put on more miles. I had the same situation, it took me awhile to get that long term average over 40, but it is now at 800 miles, a quarter tank down on my second tank of gas. You are probably aware that you can reset the average MPG that is displayed on the upper right of the IP using the reset function. It's just the long term that shows up in the one trip summary that has a bad start to it, probably from running the engine for some time at the plant accomplishing zero miles. I am not sure if there is a way to reset that number. If anyone knows, let me know. (disconnect the ICE 12 VDC battery?)

 

While I am pleased with the mileage I have to admit I am really curious how those professional drivers got 80 mpg in a production FFH. I don't see any easy way to get even 50 mpg on a tank, other than going only on a 45 mph flat road, where you can keep it in electric mode for maybe half the time.

 

It will be interesting to see if with time and development, they can move the 47 mph threshold for shifting out of electric mode up to like 65, so you could get outstanding MPG on the highway without causing a traffic jam. Any time you can shut off that ICE that's only working at 30% efficiency, it's a big plus for mileage.

 

 

 

I've only driven about 120 miles so far, and I'm less than a quarter of the way through the dealer's first tank of gas, so I can't provide a very accurate mpg.

 

I'm mainly doing short city commutes to/from work, at about 5 miles per trip, so my mileage probably is not as high as it could be. The computer says that my trips are ranging from mid 30s to mid 40s, but mostly around 41 or 42. 46.1 was the highest I've racked up so far.

 

I'm not sure how the computer calculates overall average mpg, but it is strange. I think this value started in the teens, and has slowly crept up from there. After 120 miles, I'm now up to 34mpg, even though every single-trip average has exceeded that. I wonder why it takes a while for the overal average to "catch up?" It's like I'm being averaged against some zeros, or something.

[WPWoodJr]

There is like a fan that comes on before the engine comes on, I'm guessing its the AC condenser fan, and it seems to be really loud. I may have to have that looked at.

I believe that fan is the fan for cooling the battery in the passenger compartment behind the rear seats.

[OskiO]

Last weekend my wife drove out of state for the day and I forgot to take the Yakima roof rack off the top we use for bikes. When she got back I looked at the dash and saw 32.4 MPG. Last month we took a vacation of the same distance and on the way home, 380 miles, we averaged 47 MPG on mostly old 2 lane hwy at 60 MPH. I usually get 41-45MPG on a tank for 60% suburban driving according to the computer. I've got about 6000 miles on it since June 6th.

[Noel]

I'm on about tank 6 by now, and the most recent fillup translates to 40.38mpg or so. It keeps going up each fill up. I have about 3,200 miles so far. This is peak summer, a fair amount of A/C being used, in California, and I commute about 20 miles which involves a change in elevation of about 1600 feet. I live in the foothills of the Sierra. I'm very pleased with that!

 

I have taken a few 2-4h hiway trips. I try to cruise at not more than 65mph or so. I run the tires at 40psi. Going over about 61mph or so starts to degrade mpg, as it should be expected to do so.

 

Noel

[GreenGene]

I've read in this forum that mpg will increase after a few thousand miles. I previously posted that I've been consistenly averaging 28-29mpg (with a/c full blast - 110 degrees here). I just hit 2,500 miles and it's like someone flipped a switch in the car. My last two 50 mile trips achieved 44.4 mpg and 50.5 mpg! It's still extremely hot here and the a/c and driving conditions haven't changed. Looks like my long term mpg will finally be going up! WooHoo!

[mirak]

I've been driving the car for 3 weeks but I've only racked up 350 miles so far. Almost entirely short city commutes with a few short jogs on the highway mixed in.

 

I'm doing my best to hyper-mile and the computer's total mpg has already crept up to 38.4. If I spent more time on the highway, I'd probably already be at 40+! Looks like I'll easily exceed 600 miles on the first tank.

 

For whatever reason, hybrids do get a boost in performance after a few thousand miles. I know this was true for my Highlander Hybrid and it seems to be true for the FFH as well. The FFH manual even says you can expect performance to increase. In my HighHy, this meant more robust acceleration in EV, and longer gliding in EV.

 

Can't wait for the performance boost to kick in, but it's gonna take several more months to get there at the rate I'm drivng. I suppose it's good that I'm not putting heavy miles on the car.

[mirak]

I'm doing my best to hyper-mile and the computer's total mpg has already crept up to 38.4. If I spent more time on the highway, I'd probably already be at 40+!

 

Boy was I wrong. I got to 39.2 after 400 miles of mostly city driving. Then, after my first extended highway trip of about 360 miles r/t, my average mpg fell to 37. Moderate AC use (colder than I would like but my wife was in the car) and about 74mph with mostly cruise control (faster than I would like for hypermiling but, again, my wife was in the car).

 

That's a bit disappointing.

[wstcoaster07]

about 74mph

 

I would guess that is your problem. I assume the FFH is like most cars when on ICE and the gas milage is going to degrade above 60-65ish. My Jeep's mpg starts plummeting fast when it gets above 65-70mph.

 

I assume the graph is not very precise but gives you the idea: http://www.fueleconomy.gov/feg/driveHabits.shtml

[VonoreTn]

Here is my data on my FFH since it was new, as an attached file below (click to enlarge):

 

The average fuel cost per 100 miles has been $5.71.

 

The last 4 entries have been expressway driving with the AC on, where it is harder to keep the mileage at 40. I observe that hills are harder on the mileage than AC, since we went from Knoxville to Austin the southern route, (entries 3 & 4 through Montgomery, Al), whereas we returned through a more hilly route (entries 5 & 6 through Memphis, Tn.) . The readings of the Fusion computer were very close to the calculated numbers. Our typical highway speed was 65-70 mph.

 

I assume that the mpg's would have been slightly better if we were burning pure gasoline versus the 10% ethanol that you get almost everywhere, but of course, there is not much you can do about that.

[WAFFH]

Boy was I wrong. I got to 39.2 after 400 miles of mostly city driving. Then, after my first extended highway trip of about 360 miles r/t, my average mpg fell to 37. Moderate AC use (colder than I would like but my wife was in the car) and about 74mph with mostly cruise control (faster than I would like for hypermiling but, again, my wife was in the car).

 

That's a bit disappointing.

 

Don't know if it would help the MPG but you could make it warmer on your side of the car and your wife could enjoy whatever temperature she likes. Having the ability of having different temps for my wife and me sure makes traveling a lot nicer...she is always cold (temp wise).

[fsb99]

Here is my data on my FFH since it was new, as an attached file below (click to enlarge):

 

The average fuel cost per 100 miles has been $5.71.

 

The last 4 entries have been expressway driving with the AC on, where it is harder to keep the mileage at 40. I observe that hills are harder on the mileage than AC, since we went from Knoxville to Austin the southern route, (entries 3 & 4 through Montgomery, Al), whereas we returned through a more hilly route (entries 5 & 6 through Memphis, Tn.) . The readings of the Fusion computer were very close to the calculated numbers. Our typical highway speed was 65-70 mph.

 

I assume that the mpg's would have been slightly better if we were burning pure gasoline versus the 10% ethanol that you get almost everywhere, but of course, there is not much you can do about that.

 

Nice tracking! Nice to see that some of your calculated MPG is higher than FFH estimates. My calculated is always 1.5-2MPG lower than FFH display.

[lolder]

I just completed a 2900 mile trip from South Florida to Arkansas, Kentucky and back. AC was on auto at 72 degrees, 2 people, full trunk, 35 psi tire pressure, external temperatures between 70 and 95 degrees, cruise control on all the time, speed at the interstate limit (55-70mph) but 5 mph over the lower limits and the trip mpg was 38.9mpg. Average in South Florida for 1.5 mile trips in town is 36 mpg including emissions warm up and blasting AC. Mileage is now 4400. Mpg goes down in heavy rain (-10mpg!), up in high speed or low speed traffic, down (-2mpg) on some types of road surfaces. up for tailwinds, down for headwinds. Highest several hour interstate drive was 41.4 mpg from Western Kentucky to Atlanta (downhill?), lowest from Atlanta to Central Florida (37.0). There was no hypermiling as the cruise control was always on. Watching the computer and transmission control engine RPM is fascinating. Level cruise at 70 mph yields about 1900 rpm. Going up interstate hills pushed it to 3000 rpm, going down back to 1000 rpm. The engine starts to be noisy over 25% power but on level roads up to 80 mph it is almost silent. There is a barely perceptible vibration in the steering wheel that is probably due to the 4 cylinder engine running fairly high powers and low RPM. Six hours of driving would get you down to 1/4 tank which should be about 4.4 gal. remaining but actually was about 6 gal. You can drive this car at 70 mph for 8 hours with some reserve; too long for me. There was occasionally a very, very faint fluttering moaning sound from the vicinity of the left front wheel well after rain, I suspect some water vibrating in some airflow gap. It goes away after a few minutes. This will probably be impossible to find. Having a hybrid is somewhat of a political statement. Occasionally you are driving at the 70 mph limit and someone gets close enough to see the hybrid emblem, they get right up behind your bumper to intimidate you when they could easily pass. I will probably go back to driving about 5 mph over the limit now that I have a base point but it is frequently less stressful driving at the limit although sometimes more stressful when traffic is heavy and driving faster than the limit. Go with the flow especially around Atlanta where everybody is driving 70+ in the 55 zones.

Lee

[VonoreTn]

Lee,

 

Thanks for you report. What is your overall mpg so far at 4400 miles? I don't have the light steering wheel vibration, I wonder if it's a tire. I don't think anyone has hassled me yet or even noticed I'm driving a hybrid. I don't look at it as a political statement, I just consider it to be a very smart drivetrain, that will get you diesel mpg, on clean burning regular gas.

 

Does it annoy you too, that if you forget to look at the last engine-on driving summmary, you lose it permanently when you open the door?

 

 

 

I just completed a 2900 mile trip from South Florida to Arkansas, Kentucky and back. .........Lee

[fsb99]

Lee,

 

Thanks for you report. What is your overall mpg so far at 4400 miles? I don't have the light steering wheel vibration, I wonder if it's a tire. I don't think anyone has hassled me yet or even noticed I'm driving a hybrid. I don't look at it as a political statement, I just consider it to be a very smart drivetrain, that will get you diesel mpg, on clean burning regular gas.

 

Does it annoy you too, that if you forget to look at the last engine-on driving summmary, you lose it permanently when you open the door?

 

To see your last trip summary again, you can put the key back in, turn to position 3-"on" ("start" is position 4, for reference), wait until your all of your dash displays are set and remove key. You should see the summary again. It may require you to close the doors first.

[GreenGene]

It's just the long term that shows up in the one trip summary that has a bad start to it, probably from running the engine for some time at the plant accomplishing zero miles. I am not sure if there is a way to reset that number. If anyone knows, let me know. (disconnect the ICE 12 VDC battery?)

 

I just discovered that the long-term mileage can be reset using the dash settings. Look for "resets" and select "long term".

[rickkel]

I live in San Diego that normally has very mild weather which means minimal to no use of the A/C. I usually just crack the sunroof to the tilt position which increases the airflow through the dash vents. However the last couple of weeks we had a heat wave that required the use of the A/C almost everywhere I drove. Initially I was using the AUTO setting that regulates the temperature and fan speed automatically. Indeed using that setting devestated the gas mileage because it seemed that the fan speed was always too high. Quickly I determined that this is definitely not the most efficient use of the A/C system.

 

I use the the car's computer to monitor my mileage - which I realize is not exact, but relative to my rather consistant commute I feel any big changes the computer shows is a good indicator of improvements or declines in mileage. Since purchasing the car in early June, I'm averaging about 41 mpg overall.

 

Back to the A/C topic: Instead of using the AUTO position, I used a "hybrid" of the AUTO A/C (excuse the pun). Normally I park my car in the garage at home and a covered parking garage at work, so my car is never sitting in the hot sun baking. When I know I'm going to use the A/C, I first push "AUTO" on the A/C then I immediately turn the fan to the lowest speed. I then set the temperature to 72 degrees (it's normally set to 65 degrees without A/C). Since the compressor kicks on and off based on the cabin temperature, the higher this is set, the more efficient. The cabin isn't as cool as I would normally set it, but in my 10 or so commutes using this method, my fuel mileage (again based on the car's computer) was affected minimally or not at all. I'm still getting my 41 mpg average and the drive is much more cofortable than with the A/C off. The power use guage on the dash shows only a small incremental increase once the cabin reaches this temperature (which is very quick since I park in the shade).

 

Note that this probably won't work in areas of the country with high heat and/or humidity or for those who have to park their Fusions in the baking sun, but my point is the A/C can be used more efficiently by overriding AUTO and setting the fan speed down and the temperature up.

 

Beyond any of this, my 2004 Acura TSX never got better than 29-30 mpg whether or not I used the A/C no matter how careful I drove it. I'm betting that many of you on this forum traded cars that got even worse mileage that that. Even if we get 35 mpg using the A/C that is still a good thing. So don't sweat it - use the A/C that you paid for!

[VonoreTn]

Rickkel,

 

Thanks for the A/C insights. Here's another one. When you hit just the A/C button, it doesn't automatically put in in the recirculation mode which is significantly more efficient and comfortable than the regular mode which is constantly trying to cool and dry incoming air from outside. Push the button right below the AC button with the picture showing an arrow going in a circular pattern. I used to work in climate control at Ford, and we confirmed this fact with data many times in the windtunnel.

 

I live in San Diego that normally has very mild weather which means minimal to no use of the A/C.............

 

Also thanks to others on the tip for getting last trip data restored, I'll try that when my Wife returns with the car. And also the tip that you can reset the long term average fuel economy. So that makes 4 average mpg's that I am aware of now: the long term, the easily resetable trip mpg, the last engine on mpg, and the vertical bar graph that updates every 2 minutes for the last 20 minutes.

 

On the bar graph you can change the period of time, and the bar is always one tenth of the period, 20 minutes was just the preset default.

I find the 2 minute update useful on trips for trying different driving techniques for 2 minutes at a time. I assume that since most of us on this forum are data driven, we are not still using the tree leaves.

[VonoreTn]

fsb99

 

Thanks! That works, and raised my standard of living. I made a minor adjustment, in that you don't have to remove the key at the end, just back the key position back one to position 2. Apparently once you go to position 4, start, it re-zero that last engine on mpg record.

 

 

 

To see your last trip summary again, you can put the key back in, turn to position 3-"on" ("start" is position 4, for reference), wait until your all of your dash displays are set and remove key. You should see the summary again. It may require you to close the doors first.