Can anyone explain to me why the fuel economy on the FEH/MMH takes such a big hit when traveling in cold weather? I've owned many, many vehicles over the past 40 years and never had any where the fuel economy dropped so much in cold weather.

Some specifics: I've traveled the same Interstate driving at a steady 67 miles per hour when the temps were in the 60s and gotten 30 to 31 MPG. Driving the same Interstate at the same speed when the temps dropped into the 20s yielded only 25 to 26 MPG. That's a cold weather "hit" of about 16 to 17%. With previous vehicles the "hit" was more in the area of 8 to 9%.

Again - I'm speaking only of highway economy here. I know that around town MPG suffers because of less time being spent in EV mode when it's cold. I can understand that. But when we talk highway fuel economy we're comparing one ICE to another. So what's the problem with these hybrids?

Thanks!

Doug

 

This has been discussed in the past. Some possible answers (1) winter gas formula (2) lowered tire pressure from the colder weather (3) use of snow tires
(4) decreased aerodynamics of the vehicle from snow/dirt plastered on the vehicle (5) increased use of vehicle's accessories (lights-heater-etc.) (6) others

I am experiencing 3-5 mpg loss during the winter months.

 

Thanks for your reply Bill - but every factor you cite also effects every other vehicle on the road -- as well as the FEH/MMH hybrids. As to your experience, you're only confirming the poor performance of these hybrids in cold weather.

For others who may read my original post, I might also add that the better fuel economy numbers cited were achieved when my MMH was brand new. Now with 8,000 miles on the odometer and colder weather the fuel economy is the pits!

So I again ask the question - why is the cold weather highway driving fuel economy "hit" so much worse with these hybrids than with a non-hybrid vehicle?

Doug

 

My wife drives our 08 FEH AWD, purchased Oct 20, 2007. We've gone from about 32.5 to 27.5 mpg since the cold winter has set in. And since the car was brand new when we were getting 32.5, and now has about 3K miles with the 27.5mpg, the hit is actually a little worse than shown, since the 3K miles should provide better mpg if ambient temperatures were the same. So I'm suffering about 15%-16% reduction too.

Now hear this. I drive a 2002 Ford Ranger PU, 3.0L gas, 5sp Manual, and I'm experiencing an 18% reduction in fuel mileage since the COLD weather. My SGII shows about double the fuel consumption at low speeds during warmup compared to a warm engine. Plus lubricants are stiff, so rolling resistance is considerably higher.

Cold weather and good fuel mileage are like magnetic opposites . No two vehicles are identical, and hybrids are really effected by lack of engine heat, and HV battery temp (or lack thereof), so the penalty is severe.

If you only suffered 8% loss on other vehicles, consider yourself lucky. My experience on non-hybrids is about the same as hybrids. Another thing. You are probably monitoring and paying attention to FE much more now than times past, so you're more aware of the cold weather penalty. I know I am. That's a byproduct of hybrid ownership.

Come on Spring.

 

This is a really interesting thing for me too. My MMH experience thus far has been 90% highway with temps ranging in the teens on a trip to Iowa. We got an average of 25.0mpg on that trip of ~2500 miles, which was lower than I expected to get. The car was pretty loaded though, with four adults and a trunkload of luggage.

I think things will get quite a bit better in warmer temps though. In the HCH, I managed low 40's last winter. In the summer though it was like someone flipped a switch and suddenly I was getting ~55mpg. However, now in the cold I feel lucky if I can get to work with a 45mpg average again. I'm hoping for a 20% some improvement this summer in the MMH too!

 

Did you really track your mileage that closely before you bought your MMH? I'm betting you probably didn't.

I rarely checked my mileage on the other cars I've owned. Oh, I'd probably do a quick on in the head once in a while after filling up (hm, I must be getting about 20mpg or so - making a guess within +/- 2mpg or thereabouts, that's pretty close to what I've been getting), but I've never tracked it on EVERY tank and to the tenth of an mpg before until I got my FEH.

Now it's almost a challenge for me to see if I can better my FE somehow. I've never been all that worried about it before, now I am. I HATE seeing that tank average creep down that .1 or .2 of an mpg in the morning from the cold weather warmup. And when I stop and think - sheesh, what are you doing, you're worrying about .1 of an mpg - I realize how much owning this vehicle has totally changed my attitude toward fuel efficiency.

So stop and think a bit - did you REALLY worry about the cold weather drop in mileage on your other vehicles, or do you just want to THINK you worried about it back then?

 

Interestingly enough, I've got a very good comparable--we drove roughly the same drive under the same conditions several years ago in my mom's Taurus station wagon. The trip average was ~19mpg in that car, and the MMH is not only larger but it has AWD. That helps to put the 25mpg from this trip in perspective a little.

Agreed. And more importantly, I have more fun driving either of the hybrids than any other car I've owned.

 

Chuck,

Actually, I've kept very accurate records of fuel usage since I purchased my 1st car 44 years ago. And I still have the records for the last 4 cars I owned previous to my MMH. My previous vehicle was a 2003 Olds Alero and I would usually drive that vehicle about 73 MPH on the Interstates. In the summer I would get right about 30 MPG and in the winter it would drop to 27/27.5 MPG, hence the 8 to 10% drop.

I very much enjoy driving my MMH but must admit that I sometimes feel a certain "pressure" to work harder at achieving ever better fuel economy. Since I purchased the MMH I've taken to driving slower and more importantly accelerating slower away from a stop. But I agonize over the MPG reading so much that I've sometimes taken to switching off the message center because I get too upset when I see the reading drop!

You pretty much said the same thing: "Now it's almost a challenge for me to see if I can better my FE somehow. I've never been all that worried about it before, now I am. I HATE seeing that tank average creep down that .1 or .2 of an mpg in the morning from the cold weather warmup. And when I stop and think - sheesh, what are you doing, you're worrying about .1 of an mpg - I realize how much owning this vehicle has totally changed my attitude toward fuel efficiency."

I have always been interested in fuel economy (the vast majority of the cars I've owned over the past 44 yrs have had 4 cylinder engines) but with the MMH fuel economy seems to be becoming an obsession.

Doug

 

Doug, you could try blocking off the radiator and see if it helps. As I have posted in the past, blocking has kept my cold weather drop to less than 2 mpg overall and temps are in the teens in Michigan now.

 

i know it might sound wierd for the south, but you might try an engine block heater. i have put one on my HCH up here in minnesota, and find that it brings my temps up to normal quite a bit faster than without it. i also have blocked the front. i also probably drive slower than most, since i can take backroads to work, though i can still get close to 60 on the 4 lane if i drive between 55-60 MPH. perhaps if you are able to back down just a little on the speed it might help too?