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Inviting Comments On MPG During Our Prius' Commute

Discussion in 'Gen 2 Prius Fuel Economy' started by jyl, May 26, 2007.

  1. jyl

    jyl New Member

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    The 2007 Prius #5 now has appx 7K miles. The weather is warm, the snow tires are off, replaced by the original Integrities at 44 psi F and R.

    We are averaging about 40 mpg in all-city driving.

    The average trip for the Prius is 14 miles roundtrip, started from cold, my wife driving 7 miles from home to the kids' school and then 7 miles back home. On the outbound trip, the first 4 miles is city streets at 25-35 mph during which she drops from appx 150 ft elevation to appx 50 ft then back to 150 ft. The last 3 miles is somewhat curvy and somewhat hilly roads at avg 40-45 mph, during which she climbs to appx 800-900 ft elevation, then drops to appx 500 ft. The return trip is just the above in reverse. She does this trip once in the morning and once in the afternoon. The car is carrying one adult and, half the time, two children. (For those familiar with Portland, this is a trip from Northeast Portland, through downtown, over to Forest Heights, and then back.)

    My wife drives the Prius like a normal car, and as mentioned she is averaging 40 mpg. On days when I do the drive, I accelerate smoothly, glide (coast w/ no power arrows) whenever possible, and generally drive about 5 mph slower than she would (the speeds above are her averages). I get somewhat better mpg, but only by about 2-3 mpg.

    What do you think about this mileage? Should it be better?

    I read here about people averaging 50+ mpg on their commutes. I'm wondering if those commutes tend to be mostly freeway and on very flat terrain. Or with more broken-in Priuses.
     
    #1 jyl, May 26, 2007
  2. Prudence

    Prudence New Member

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    <div class='quotetop'>QUOTE(John L. @ May 26 2007, 11:31 PM) [snapback]450640[/snapback]</div>
    My Prius has 2200 miles on it now. I started off with 49.5 mpg and hit 52.8 mpg and my first 500 mile tank tonight. My commute is 25 minutes with a mix of in town and interstate. I climb out of a valley going and get better mileage coming back. The in town has a lot of hills, so I get a lot of regen, my battery is green most of the time because of that.
    We have an engine block heater installed, I use it on weeks days but not on the weekend. My first five minutes are better because of it. Instead of 25 mpg, I get around 45 mpg for those first five minutes. Over time that little bit will add up.

    My guess for people that get 50 mpg+ probably have a longer commute than your 7 miles there and back. I'm sure others will have more thoughts and help on this for you.
     
    #2 Prudence, May 26, 2007
  3. likesmpg

    likesmpg Junior Member

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    I think your trips are just a little short. I'm at 1600 miles and my tanks have been 56.2, 58.5, and currently 61.8mpg. My commute is ~15 miles one-way, little to no elevation change, I drive very conservatively, and it hasn't been below 60-degF. I pulse & glide as much as possible. I can't wait to get my engine block heater; in the mornings I lose ~0.3mpg on the average and then struggle to 'recover' it by the time I reach my destination. I didn't think I would worry about mileage at all anymore driving a Prius, but I think I'm even more obsessed now!
     
    #3 likesmpg, May 27, 2007
  4. alexstarfire

    alexstarfire New Member

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    Unfortunately it's because of your temps there and the speeds driven at. Those first 4 miles she is easily using up half the gas on the entire commute, those speeds really suck when the gas engine is running all the time. On the hilly part you could probably do a bit better. Just remember that when going down one hill and an uphill part is next, that you need to go faster than what you want to end at. Like if you want to end at 40 MPH, I suggest getting up to 50 MPH or so by the bottom of the first hill and then "burning" those extra 10 MPH off so that you aren't over-reving the engine. You basically want to try and keep your engine revs the same on the downhill and uphill parts.

    It takes time to get used to it and figure out what is best.

    I'm currently averaging 61.9 MPG (MFD) and it's pretty hilly around here. About 6-7 hills, I don't count them, that I have to go over going to and from on my daily commute of not even 10 miles each way.


    Ohh yea, if you can, make sure you try and use your battery to coast over the small hills. The ones that are like 10-20 ft high. The should help a lot. Ohh yea, coasting to known stopping locations always helps a ton. Can't beat free mileage.
     
    #4 alexstarfire, May 27, 2007
  5. bulek

    bulek Junior Member

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    <div class='quotetop'>QUOTE(John L. @ May 27 2007, 05:31 AM) [snapback]450640[/snapback]</div>
    I think (looking at my experience) your wife gets perfectly "normal" fuel usage with this distance and driving style.

    - Piotr
     
    #5 bulek, May 28, 2007
  6. Wayne

    Wayne Active Member

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    Are you getting 40.0, or 40-something? I have a 7-mile 1-way commute also, over mostly flat terrain, and I average 48. Of course I mix in a TON of VERY short trips to fast-food restaurants, which definitely hurts me, both physically, and in the MPG department. :)

    To achieve really good mileage, you have to give the battery a chance to work, and avoid acceleration. Sounds like you spend half your journey in constant acceleration.

    For reference, I have done a 2-hour test in our downtown (where the speeds are 30-35 and the lights are synchronized), and there, this 48 MPG boy got 72 MPG (even turning around and getting back up to speed every few miles!)

    Your techniques appear sound. If your wife follows them, you will probably see a few more MPG. Unfortunately, that route doesn't sound like one where the car will see optimum MPG.
     
    #6 Wayne, May 28, 2007
  7. jyl

    jyl New Member

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    Wayne, the average is 40.0, not 4X.X

    Thinking about it more, the main mpg killer seems to be the climb from appx 150 ft to appx 800-900 ft in about 2 miles. It isn't numerous little hills, it is one fair-sized hill. Some of that climb is one-lane in each direction, so you have to keep up with traffic which is moving 40+ mph. Mpg suffers on the oubound uphill.

    On the return descent, in glide mode the Prius will approach 80 mph, which isn't practical (traffic, curves, law), so you have to brake often. At the base of the hill the road abruptly enters a dense commercial area with traffic lights, so you can't carry your speed from the descent. Of course, the SOC is green by this point.

    Still, I think we should be getting better mpg on the flattish parts of the commute.

    As for freeway, the Prius seldom leaves town, but on Saturday we drove 80 minutes on flat freeway, no wind, average 60-65 mph, with two adults and two children (for Portlanders, that's from Portland to Woodburn on the I-5, and back). No driving tricks, just holding the speed constant (was even on cruise control for a while). Mileage for this trip was appx 50 mpg.

    At the next service, I will ask the dealer to check alignment and brake dragging. Oil is not overfilled. Anything else to check?
     
    #7 jyl, May 28, 2007
  8. Wayne

    Wayne Active Member

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    Well, 50 MPG at 65 MPH isn't too out of line. I get 55 MPG at that speed (see my signature). I get 50 MPG at 70 MPH, but I live in a flat area, and use cruise all the time on the highway.

    Your car does not seem to be malfunctioning to me. There may be some optimizing you can do personally that may raise your MPG a bit, but I'm afraid you aren't in the best-suited location...
     
    #8 Wayne, May 28, 2007
  9. bwilson4web

    bwilson4web BMW i3 and Model 3

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    <div class='quotetop'>QUOTE(John L. @ May 28 2007, 11:36 AM) [snapback]450998[/snapback]</div>
    It looks like you may be a candidate for a block heater. Even during the summer, this will save the warm-up gas costs.

    Bob Wilson
     
    #9 bwilson4web, May 28, 2007
  10. dmckinstry

    dmckinstry New Member

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    <div class='quotetop'>QUOTE(John L. @ May 28 2007, 09:36 AM) [snapback]450998[/snapback]</div>
    Although brake dragging and alignment could be a problem, and I would check them (as well as tire pressure), I suspect as you do that a large elevation change in a few miles is the main culprit. You can't get back all of what you lose on the downhill. At 40 mph over a long distance with an elevation change of 400-500 ft. I can do better than 60 mpg, but that's just for those part of the trips. Where I lose my mileage is non short trips (2-5 miles at a time).

    Dave M.
     
    #10 dmckinstry, May 29, 2007
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