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Prius MPG on short winter trips.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by rubberpill2002, Jan 21, 2009.

  1. rubberpill2002

    rubberpill2002 New Member

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    I understand that the Prius MPG on short winter trips could be very low since the engine has to warm up. But what if you were to start the car in your driveway and let it warm up just sitting there and then drive it. The interior would be warm obviously, but would the MPG improve?
     
  2. andyprius

    andyprius Senior Member

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    Do you actuall now own a Prius?
     
  3. rubberpill2002

    rubberpill2002 New Member

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    No, I am considering getting one, but my commute is only 15-20 minute in city driving each way. Is it possible to warm the car sitting in your driveway? Will this improve MPG?
     
  4. JimN

    JimN Let the games begin!

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    No. Please describe your trip. Is the speed steady? Do you sit in traffic? What is the climate & terrain? Expect the 1st 5 minutes to be at 25mpg. The following segments could be at or close to 50mpg. Overall I would guess you could see high 40's.
     
  5. andyprius

    andyprius Senior Member

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    I"ll try to keep this straight, IF one drives any car and then lets it idle in the driveway, the car will get poor mileage. To do this with a Prius would be totally contrary to the whole concept of fuel efficiency. But please continue to read all the posts in Priuschat, especially MPG Did you know that in some countries it is recommended that you shut off your ignition while waiting at a red light! Why would they do this? EDIT: The answer to your original question is NO.
     
  6. rubberpill2002

    rubberpill2002 New Member

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    You still have not answered the question. Can you warm the engine up sitting stationary in the driveway? The question has NOTHING to do with anything else but mechanics. And if this is possible, would it improve mpg during the short drive that follows? I am not asking if this is a good idea, I am asking if it is possible.
     
  7. Patrick Wong

    Patrick Wong DIY Enthusiast

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    2G Prius will shut off the engine several seconds after you commence a cold start. Hence the engine will not warm up when the car is sitting stationary. However, Classic Prius will run for several minutes from a cold start.

    If you want to force the Prius engine to run, it is possible to invoke an "inspection mode" which will make the engine run continuously. Note that it is not recommended to drive the vehicle in this mode as traction control is disabled and the transaxle may be damaged if the front wheels lose traction.

    Since you will consume gasoline in warming up the engine while the car sits in your driveway, I would say that your overall mpg will generally be adversely affected if you allow the car to sit to warm up, vs. if you start driving and let the engine warm up while the car is underway.
     
  8. Neicy

    Neicy Member

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  9. andyprius

    andyprius Senior Member

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    Last question: Would MPG improve. My last answer: NO. ( looks like an answer to me )
     
  10. rusty houndog

    rusty houndog mountain rider

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    The fastest way to warm up any ICE is to use it doing work. Driving the car, no matter how low the MPG, is far better than any amount of time spent burning fuel in the driveway at zero MPG.

    The answer to your question is no, the MPG will NOT improve. Just get in it, start it, and drive away.

    It's an electric car when it starts and an electric car when it runs. The ICE just supplements all that power collected during dynamic braking. It's almost a perpetual motion machine! Hmm?
     
  11. bedrock8x

    bedrock8x Senior Member

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    The most effective way to improve mpg in winter is to install an engine block heater (EBH) and warm the engine up four hours before the morning trip.
     
  12. andyprius

    andyprius Senior Member

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    Hello RubberPill: If you are still there, Yes you could warm it up, just MAX all the heating controls, leave it in that state for at least 15 min. Would MPG improve? Improve from what
     
  13. andyprius

    andyprius Senior Member

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    Hello again RubberPill: I have consulted my 17 year old Granddaughter with your question, I wanted a professional opinion! She iterated that any advantage you may gain from warming up Prius would then be negated by decreased fuel mileage. My Granddaughter is thinking of opening up a Enquiry Show, it will be called " Ask Chrissy " so, stay tuned.
     
  14. nerfer

    nerfer A young senior member

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    Your answer is a qualified No.
    The car's engine would warm up, and it would improve the mileage of your drive, but it would reduce your overall mileage, because so much gas is spent while your car is not moving. It comes down to basic mechanics, and is true for any car, not just the Prius. Spending time warming up the car worsens your total mpg. No matter what.

    That said, 15-20 minutes is not that short. I have an 7-8 minute commute, and with temps between 0 and 20 (Fahrenheit), I get 36 mpg (I get 49 mpg overall, with long trips and summer weather included). You don't list your location, so I don't know what it's like for you. The first 5 minutes are about 25 mpg, then it improves considerably. Adding an engine block heater, so the car is warm before you even turn it on, would help considerably, and I need to do that. That would be a much better solution for you.

    Also having the heater on full-blast will hurt mileage especially on short trips.
     
  15. tarun101

    tarun101 New Member

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    I agree with nerfer. I have a 3 minute commute in VA. Temperatures have been 15 to 35 here.

    Letting the car sit in winter before my commute makes the overall mileage go down (even though the mileage for the trip increases). It still makes the car warmer when I get in so I do it anyway :)

    I get about 35 mpg overall for this commute and probably one longer drive (10 miles or so each way) every week. Its low but still a heck of a lot better than "other" cars.