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LOW MPG's on new Prius C????

Discussion in 'Prius c Fuel Economy' started by NMW1982, May 16, 2012.

  1. Ashley7

    Ashley7 Active Member

    Joined:
    Mar 19, 2012
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    Location:
    Oregon
    Vehicle:
    2019 Prius
    Model:
    XLE
    I have a short commute also--about 3.5 miles. On my first tank, it showed that I averaged around 45 or so. So far on my second tank, I'm averaging 51.8. A combination of the engine starting to break in, the weather getting warmer and drier, and more driver knowledge/experience has definitely improved things some. Some days I find myself wishing I had a longer commute, just so I could see better numbers :rolleyes: I don't usually reach 40 until I'm over half way to my destination.

    Obviously it's hard to compare car to car since everyone's commutes (and driving styles) are so different. I wouldn't start to worry until you've gone through a few tanks, and have a better idea of what you're really getting. Take advantage of some of the tips people have given, and we'll all keep our fingers crossed for you :)
     
  2. kkim

    kkim Active Member

    Joined:
    Jan 27, 2007
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    Location:
    kauai, hawaii
    Vehicle:
    2012 Prius c
    Model:
    Three
    Thanks... sorry, I missed that.
     
  3. walter Lee

    walter Lee Hypermiling Padawan

    Joined:
    Oct 26, 2009
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    376
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    Location:
    Maryland
    Vehicle:
    2010 Prius
    Model:
    III

    The Prius' mpg varies with the seasons, in warmer temperatures as long as you don't need to turn on the AC, the Prius mpg can be very high. During summer time, when it gets really hot and you need the AC and during wintertime when its really cold - the Prius Mpg drops. As the temperature warms up to the 70s and 80s - the Prius' mpg should increase too.

    I'm getting +60mpg because I am hypermiling my 2010 Toyota Prius III - it is not for everyone - because it trades time for fuel efficiency.

    If you want to learned a few hypermiling techniques - a good place to start by reading the FAQs at cleanmpg.com on priuschat.com or by watching some videos on youtube.com.. Many of the techniques sound simple but many of them favor certain road conditions that require a driver to select only certain roads. Unless you are using that same route over and over again like in a commuting trip - its a rather high overhead for trip planning. Hypermiling techniques like DWB and rabbit timing sound simple but they are problematic in the sense you cannot always use them -it is sort of like sailing - the right conditions have to be there but when those right conditions are there a hypermiler can make a car go a bit longer for the same amount of fuel. Below is an explanation of two such techniques...

    In the hypermiling technique called *Driving Without Brakes" (DWB ), a driver avoids using his brakes by allowing the car to naturally slow down to about 15mph to 5 mph before using the hydraulic brakes - this means the driver needs to determine the top speed and distance that can be achieve before he turns off the IcE/electric motors and allows the Prius to glide to stop. The top speed and gliding distance changes with the smoothness of the road, the grade of the road, whether the road is dry or wet, the type of tire (non LRR/LRR), and tire pressure. Tires can be overinflated to reduce its rolling resistance so it can glide a bit longer than normal on a dry road (but when the road is wet and the gliding distance is likely to be much shorter on rainy days). Let us say a Prius is at a dead stop in front of a traffic light that has just turned green. The driver sees then next traffic light about 300 feet away and it is Red and likely to stay so for the next 8 minutes ( it is a long light). The Prius must travel on a dry flat road, a driver estimates that he needs to accelerate the Prius to a top speed of 25mph about 1/4 way (70 feet) before turning off the gasoline engine and allowing the Prius to glide the next 3/4 of the way on its own momentum. The driver accelerates from 0mph to 12 mph using the electric motors then presses the accelerator a bit harder going pass the middle of the HSI indicator to trigger the gasoline motors to go from 12 mph to 25mph. When the Prius reaches 25mph, the driver backs off the accelerator, the gasoline engine shuts down and the electric motors are running only slightly or not at all. The Prius slows down from 25mph to 11 mph before the driver has to apply the hydraulic brakes to do a full stop at the next traffic light. When there is traffic, this technique is more likely to be tolerated when done on multi lane roads when the speeds are under 30 mph and when done in the right lane.


    A *countdown* pedestrian timer adds a new twist to DWB -- If the traffic light is green and the countdown timer is <10 that means the Prius has about 9 seconds to make it through that light before it turns red - the driver must determine whether to speed up to make the light or slowdown to a stop.

    When a traffic light is red and it has a *countdown* pedestrian timer, a driver can use *Rabbit Timing* to pace the Prius's speed so that the Prius is still going at 15mph when the light turns green and all the cars in front of it are moving at +15 mph. By looking at the countdown timer, a driver can estimate when the light will turn back to green thus avoiding having to do a complete stop. By avoiding a complete stop, the Prius conserves its momentum and increases its fuel efficiency. Rabbit Timing favor roads with traffic lights over stop signs.