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Understanding cold weather MPG

  #11  
Old 12-02-2007, 07:25 AM
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Default Re: Understanding cold weather MPG

Many Prius and HCH-II owners use the copper tubing foam covers that you get at Home Depot in the plumbing section. Cut the segments to size and feed them to the front grille openings with some tie wraps. Works well for many and costs only a couple of bucks.

You see some examples if you do a look-up on the HCH-II forum.

Cheers;

MSantos
 
  #12  
Old 12-03-2007, 11:57 PM
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Default Re: Understanding cold weather MPG

So is the general consensus that it's better to slowly warm your car up (low load, low RPMs, neutral) as opposed to driving "normally" to get the engine up to temperature quickly?

I go down a 2-3 mile hill on the way to the freeway, coasting in gear, and I've noticed that the coolant temperature usually plummets, regardless of RPM (~3000). Keeping the A/C on helps, but that would burn even more fuel, wouldn't it? And since I'm coasting downhill, with the fuel injectors presumably "off", I'm not burning any fuel anyway.
 
  #13  
Old 12-04-2007, 12:39 AM
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Default Re: Understanding cold weather MPG

Originally Posted by empowah View Post
So is the general consensus that it's better to slowly warm your car up (low load, low RPMs, neutral) as opposed to driving "normally" to get the engine up to temperature quickly? . . .
One should avoid loading an engine running a rich mixture. The trick is finding out when the car has switched to a normal mixture and that is difficult without instrumentation. However, the transmission may take a little longer to warm-up.

Bob Wilson
 
  #14  
Old 12-04-2007, 09:27 PM
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Default Re: Understanding cold weather MPG

I agree with Bob. Take it easy until the engine is out of "MPG and emissions be dam*ed, warm-up mode". You'll be better off in overall MPG this way, and pollute less too.
 
  #15  
Old 12-05-2007, 08:30 AM
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Default Re: Understanding cold weather MPG

My morning commute consists of: 15 to 20 MPH 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.
 
  #16  
Old 12-09-2007, 08:29 AM
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Default Re: Understanding cold weather MPG

Ford acknowledges a 25% loss in Fuel Economy during cold weather.

That would mean about a 8 MPG loss. But they also consider cold to be zero degrees, and you will often see less than that, so a 10 MPG loss is "normal".

With use of my block heater for 3 hours ( which incl. a battery heater for 2005-2007's ) I have EV conditions within 3/4 of a mile from my house.
I'm getting less MPG for sure, but more like a 3 MPG to 5 MPG loss at zero degrees.

I'm sure you smelled rubber tires "burning" and not the electric motor.
 
  #17  
Old 12-10-2007, 12:56 PM
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Default Re: Understanding cold weather MPG

In the winter, is it not only cold, but it is also dark. So, I am actually commuting to work in the dark, both ways.

I wonder if running with the headlights 'on' all the time, affects the mileage too?

BTW, this morning it was foggy too. So, I also wonder if driving with the fog lights 'on', reduces mileage too (additional drain on the battery when in EV mode)?
 
  #18  
Old 12-10-2007, 03:12 PM
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Default Re: Understanding cold weather MPG

When you have the headlamps on, you also have the tail lamps on, and the running lamps ( parking lamps ) on.

Ford did the math. At night, all the lamps combined cost you 0.9 MPG.
I think they said running the rear resistive defroster costs you 0.3 MPG.
-J
 
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