I just posted this in the Fuel Economy thread "Understanding cold weather MPGs" but thought it appropriate here, too. I'd love to have someone help me figure out what the heck is going on or someone who lives in a warmer clime who wants a very slightly used FEH.
My morning commute consists of: 15 to 20 miles per hour through the neighborhood (about a quarter of a mile), 35 MPH on the main roads to the freeway (about 3 miles, with a quick stop for coffee on the way, and I turn the car off at the coffee place and go in), then about 20 miles of freeway (45 to 65 MPH depending on the segment), then about 1 mile on city roads. I usually can get into EV by the time I hit traffic about 20 minutes/15 miles in. I'll stay in EV about 20 seconds (if I'm lucky). I have shut off the radio and climate control to help stay in it, but I leave my lights on since that's required during weather. I have plummeted from 33 MPG to 22 in the last 10 days. I have not changed gas brands. I hit 10000 miles yesterday. I have spent a lot of time in bumper to bumper thanks to the never ending snowstorms and Minnesotans' inability to drive in the snow despite the fact that this happens every year.
If the average loss of MPG due to cold is 10 to 15%, then I should be getting closer to 30. Temperatures have been in the single digits in the morning rising to the teens for the highs. I plug in the engine block heater while at home but can't do that at work. Is this normal, or should I take him in to the dealer? I know the hybrids don't appreciate cold weather, but not working at all? I was getting 19 to 20 MPG in the coldest part of winter (always subzero) in my gas V6 AWD Escape, and I'm already missing the AWD part, having been stuck in snow several times with my wheels spinning away and smelling my electric motor burning.

 

Mary, let me throw out some possible problems that could be effecting your mileage. Assuming you got 33mpg driving the same route and stopping for coffee each time, consider a change in fuel quality, long term fuel map changes and add that to the cold effects on the HV battery and regen.

When you lose EV to the cold weather, the FEH takes a turn to being a regular vehicle in stop and go driving. On top of that, the engine is a Atkinson cycle and needs the electric motors to assist with torque. At that cold of temperature, your regen is of very little use, so the engine has to keep the HV battery charged by itself. A sudden change in colder weather will cause your fuel maps to be off, and will need time to readjust.

With your background, you should know how ethanol effects the FEH/MMH. It didn't matter that I didn't change brands, the E10 I got was from a gas station I use all the time that never had E10 before. It could be a tanker driver made a mistake and filled the storage tank at the station you got gas with E85 or something.

The comment you made with regard to spinning your tires and smelling your electric motor burning concerns me also. If it wasn't the tires causing the smell of burning, you may have real problems. If the smell was coming from the electric motor, you do have problems.

You should have not dropped from 33mpg to 22 just because of the colder weather, but these fuel trims can have an effect for a while.

GaryG

 

Cold weather makes a huge difference in mpg in my experience anyway.

I live in Rochester NY & we had a stretch last Winter where it stayed at something like 12º the whole time.

I got so disgusted at the mpg I was getting during that time that I totally gave up on even caring about mpg & went back to driving my FEH like I used to do in my younger hotrod days (I am an old time NHRA drag racer).

That was kinda fun actually to take out my frustration on the truck, because these vehicles are pretty snappy (at least at lower speeds) & stepping on them hard can be kind of entertaining at times....;-)

~John

 

I think you shouldn't worry about the CR reports as long as they are consistent across different cars. So if they rate the 30MPG FEH at 26 they should rate the 22MPG Cherokee at 19. That's all relative.

The way my stepson drives, if I let him drive my '08 FEH it would probably get about 12MPG. And break down at 8,000 miles.

 

Thanks for the heads up. I'll try not to get discouraged if my mpg's are not as high as expected.
btw...I like your pics. Are all those screen display pics from the Eclipse system?

 

Yes, they are. I replaced the factory NAV setup that came in the truck with the Eclipse 5510 & it is a really awesome unit.

I also have a Garmin NAV setup hooked to the setup & can switch back & forth between the two although when those pics where taken, I hadn't gotten around to hooking up the Garmin.

Each NAV unit has its advantages/disadvantages & I use both setups all the time.

~John

 

VERY NICE!!!

 

I just checked the Consumer Reports website.

They got 35mgp in a Prius in the city.

How the hell do you only get 35mpg in a Prius???

They must drive like Mad Max!

(And 16 in the City for the Highlander Hybrid)???

 

I agree! They must abuse these vehicles while testing.
I am now convinced that you can't believe what you read from these reviewers.

 

Interesting thread! I've just encountered my 1st cold weather, since I decided to head north and spend the upcoming Holidays with my kids and grandkids in Michigan. On the way north from Alabama temperatures dropped into the 20s today and that has caused my MPG readings to fall into the upper 20s (like the temps!). (I have over 6,500 miles on my MMH and have averaged 32.5 MPG for 14 tanks previously.)

With over 300 miles on the current tank, my fuel computer says 27.1 MPG (I was battling 30 MPH head winds on top of the low temps) and I know that my fuel computer has been reading about 2 MPG high to actual so that means I'm really only getting about 25 MPG on this tank!! That's over 3 MPG lower than my previous lowest tank! Not good news at all!!