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Hybrid Vehicles Toyota Prius Toyota Prius MPG-Real World Numbers
767 messages, Last post on Sep 28, 2009 at 9:21 AM
You are in the Toyota Prius Forum. Your Host is pf_flyer
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Replying to: prius2007 (Oct 27, 2008 6:46 pm) Due to variabilites beyond our control from the gas station to the fuel tank/bladder to the outside environment watching one tank or another is far too specific ( looking at a tree ) to have any concern. Only after accumulating a sufficient amount of data can one really determine what the vehicle truly is using in fuel. This will take a year or two ( the forest ). And the result will be be about 47-48 mpg. A couple of other important suggestions: 1. Short trips are death on fuel economy. You can see this on your MFD every day that you drive. Look at the first 5 min bar on the CONSUMPTION screen. It will almost always be 25-35 mpg. THIS is the anchor that is holding down your average fuel economy. Having to overcome this first 5 min of relatively inefficient driving brings down your daily/weekly average. DON'T TAKE SHORT TRIPS!!!!! 2. DON'T STOP - EVER!!!! This may seem ridiculous but no vehicle can overcome Newton's First Law of Physics. Succinctly a body at rest will remain at rest unless a superior force overcomes it's inertia. When you come to a stop light or stop sign normally you will stop the vehicle. It takes a huge amount of energy to get the vehicle rolling again. That energy always comes from the ICE through burning fuel. Now some of it may have been stored in the battery previously so it's the stored energy that first gets you rolling away from a light but all that does is deplete the battery quickly such that the ICE has tokick in sooner and replace the used energy in the battery reserve. You will likely get your best fuel economy on a 30-60 min trip where you never have to stop and you must keep to driving at about 35 mph due to traffic or to road laws. I've averaged 65 mpg for such a 50 mi trip. 93,000 miles with a lifetime average of 2.1 gpc used ( 47.9 mpg ).
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Replying to: phd86 (Oct 28, 2008 6:44 pm) |
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Replying to: cdhc (Oct 24, 2008 5:11 pm)
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Replying to: kdhspyder (Oct 29, 2008 9:36 am) 2. DON'T STOP - EVER!!!! This may seem ridiculous ...When you come to a stop light or stop sign normally you will stop the vehicle. It takes a huge amount of energy to get the vehicle rolling again. You will likely get your best fuel economy on a 30-60 min trip where you never have to stop and you must keep to driving at about 35 mph due to traffic or to road laws." Thanks for the great  advice spyder! "Don't stop - ever" ... "normally you would stop...". You must have a lot of followers, based on my observation of driving behaviour. Can you please help me with my mileage? I'm struggling  So far have driven 26,999 miles since Apr 2007 and pumped 455.46 US gallons of fuel. No matter how hard I try I can't average " And the result will be be about 47-48 mpg". I can't even get that on a single tank let alone overall. Can you help me out please? I do stop when I have to (stop signs/light ...) and I do take frequent longer trips than the 30-60 minutes you stated as best for MPG. I admit  driving on the HWY (50% of my driving is HWY) and do go up to and over 60 MPH. Are these the reasons why I can't get your predicted 47-48 MPG? Thanks in advance for all your help Gabe
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Replying to: jana6 (Oct 30, 2008 4:41 pm) |
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Replying to: cdhc (Oct 31, 2008 6:56 pm)
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Replying to: cdhc (Oct 31, 2008 6:56 pm) Your advice is good in fact I do the same, but if you listen to the experts / people with more experience with the Prius they will tell you this: There is an energy conversion loss (gas to electric or electric to kinetic). Guess well all the stored battery energy comes from - yes your gas engine. Initially it had to come from the battery and any replenisment has to come from the battery. They recommend to stay off the battery and that a no arrows glide is better than running off the battery. Like you, I also coast (blue arrows only going to the battery) when approaching a red light / stop sign. I've been doing more gliding (no arrows) as a result whenver possible, but since I don't want to hold up traffic I do also run on the battery often. Good luck sounds like you're doing well  Gabe
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Replying to: jana6 (Oct 31, 2008 7:08 pm) You hit the nail right on the head - the claim is that there is no friction when gliding. BTW the Prius MFD is great in showing instant MPG but it only goes to 99.9. I recently bought a Scangauge which goes up to 9999 MPG and even better if you switch it to L/100KM a zero reading means there is not even a trickle of gas is being used when gliding. Best of luck , sounds like you got the bulk of the concept and you can put it into practice, Gabe |
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Replying to: prius2007 (Oct 31, 2008 5:32 am) You obviously got the secret Super Ultra Efficiency option package that very few knew about and which allows you to be in the upper 1% of all Prius owners. I didn't know the code for that option or I would have chosen it also. For the rest of us plebians we have to make do with just good normal results. Nice hand, sir. |
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Replying to: jana6 (Oct 31, 2008 7:08 pm) When you are driving, and you take your foot off the accelerator (coasting), the car then uses the momentum of the wheels to back-drive the electric motor, thus charging the battery. This method of charging is much more efficient than regen braking since there will not be as much energy lost due to heat being generated. Its true that gliding can help you go a little further than coasting, but gliding does nothing at all to charge the battery. What may be perceived as friction while coasting is actually the electric motor being back-driven. And yes, with any rotating part, there is friction. That's just something that cannot be avoided. You even have friction in the wheel bearings while simply gliding. I don't know. There's people that get better gas mileage than me, but I'm happy with my average of 57.5.
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