A week ago I decided to reset mpg on my 2010 FFH, which had been very very slowly increasing during the warm summer, and was at 42.3mpg the day I hit hit button. It had been maybe 8 months since it had been reset.

Much to my surprise, I'm getting 45.7mpg now, and I'm still increasing. I live at 2,000' elevation, and commute to the valley floor at about 500'. So of course I did the reset at my home.

All this suggests my peak winter mpg must be down in the 35-37mpg range, because I never went under 40mpg the entire winter. I just never saw it because I never reset it. If this is a correct interpretation (I'm driving more efficiently now, but not THAT much I don't believe), then I am seeing a temp-dependent variation of 15-18%. That seems like a lot, but I guess with chemical batteries, it could very well be.

Noel

 

You are seeing things just perfect.

Mileage is lowest in cold temps for sure.

Mileage is highest in the warmest temps you can stand to drive without AC.

The mileage graph is very simple if you never use AC, the warmer the temperature the higher your mileage.

AC use throws a monkey wrench into the works as AC robs power and decreases mileage, but generally not as bad as really cold winter temps.

AC users generally see twin peaks in their yearly mileage, one in Spring and one in the Fall. Winter is always the worse and Summer is better than Winter but not as high as Spring and Fall due to the AC use...

 

Your synopsis is 100% compatible with what I am seeing. I was surprised (sort of!) to see just how much impact A/C has on mileage. I did a 110m round trip commute today from 2,000' to 400' over 10 miles, then 45 miles on the relative flat, then the reverse. I started out at 45.7mpg this morning, and ended up at 44.9. I used A/C about 3/4 of the way home. I have not been using A/C over the past week of 22m commutes up and down the hill. Anyway, 44.9 is still pretty dang good, and I can see the coming fall weather will be ideal for best mileage. I am judicious with A/C most of the time. The other reason I lost a little mpg today was I had to speed home to meet someone part way home, so fudged my usual conservative driving practices.

 

AC lower MPG by 25% in typical city conditions and 10% on the highway.

AC takes 3-5 horsepower. In the city, you can drive with 15-20 horsepower.

 

25% seems way too steep, but you sound like you know. If I am getting 45mpg in the city now, this suggests 33.75mpg, which is way way way under what the car does w/ A/C on. It's more like 42.5 or so with A/C, at least's what it is for me. Once the A/C has been on a few minutes the power use goes way down it appears which would help explain why there is not so much loss of mpg that I am experiencing.

 

Of course. I was talking continuous, or "max" A/C use.

If it is cycling on at 50% duty cycle, your reduction in MPG is half as severe.
And Ops! My specifc example was with an Escape Hybrid, but the results are similar.

 

Noel, we're not talking apples to apples here with gpsman1, and you have an older FEH and can see the difference in MPG with your '10 FFH engine. The A/C belt driven compressor in the older '09 and earlier FEH operates completely different and can't be compared to the electric A/C compressor in the FFH as far as MPG or horsepower. Without the A/C, the FFH wins MPG by far over the '08 and older FEH without A/C in cold or hot weather. However, if you run the A/C in your FFH in city driving your not going to see any long term EV mode. I've read that the electric A/C compressor eats up .1% of SoC a second in EV mode without regen or MG1 charging with the engine running.

Your FFH should get year a round improvement in MPG than the '08 and earlier FEH because of changes in computer strategy during warm-up and newer engine design like in my '09 FEH.

GaryG

 

Sure. Interesting to see the difference in summertime mpg (w/o AC, or with limited A/C) over the long term average. Getting over 45mpg now w/o extreme hypermiling techniques per se. The pulse and glide in neutral has limited applicability secondary to my particular terrain issues and desired routes to drive and so forth. I do use it, but often it's quite obvious it's smarter to shift back into D so I can charge the battery as I'm approaching a stop or slowing. And it's a bit hot here right now so I do use some A/C. I'm imagining by the end of the summer and the first 2/3 of Fall I will probably see 47 or 48mpg as it's still on the rise, except as I say if I'm in a hurry or need more A/C.

 

This is the best summer MPG I've ever seen in my '05 or '09 FEH. It's hot now and the ocean waters are the hottest I've seen here in Florida. My '09 FEH uses the A/C compressor to cool the battery but I haven't turned On my cabin A/C at all this summer. The battery A/C keeps my battery temperature at the most efficient operating temperature possible so battery management during P&G is at its best in hot weather. The engine is at its most efficient temperature and is maintained during P&G in hot weather. This summer has been the perfect storm for the '09 FEH, even on 10% ethanol. The key is no cabin A/C, good P&G and all other hypermiling techniques and reducing as many stops as possible during the day.

The tank I'm on now will most likely be the best tank ever recorded in a non plug-in FEH. I've never seen the kind of mileage I'm getting in my '09 FEH and frankly never expected to. Today, my Nav Sys tank reading is at 66.3mpg and the trip OD is at 678.4 miles. Based on prior tanks, I should get a total distance of 840 miles on 13.6 gallons of gas which would be a 61.7mpg tank average. This is the difference with not using the cabin A/C in hot weather. My lifetime MPG should jump to 52.4mpg after this tank with about 24,690 total miles on my '09 FEH after two years of ownership.

With the FFH, the battery can only be cooled with the cabin A/C so your battery may not be as efficient in real hot weather. Your engine should be more efficient than mine without a belt driven Aux battery A/C compressor like I have. Overall, our FEH and FFH MPG should only be effected by body style, tire size and weight given the same terrain and weather.

GaryG

 

I feel I've seen quite a bit of what it must take to be able to report those numbers, and as I've said before, it's some pretty artificial conditions, that is to say they won't fly for most folks in their particular terrains, temps, hills, stops, traffic, etc. But it's great for braggin' rights no doubt. I'll be jumpin in to one of these babies and then we can talk mpg

https://www.greenhybrid.com/discuss/...1&d=1282182106