Purchased a Blue Ribbon Metalic Prius II on 11/17. The wife and I liked it sooo much, we traded in my '08 Honda Fit on 11/29 for a 2nd one. We now also have a Prius III with the Solar Roof Nav. Pkg. in Blizzard Pearl. SWEET!!! So today I drove the III home from work. I have been averaging on the display, about 62-63MPG over the first 200 miles, but today decided to reset the B tripometer for the drive home. To be fair, if you're familar with the Phoenix area, the drive from near Cave Creek, AZ to N. W. Phoenix has a drop in altitude of about 800', but even so, over a 14.3 mile trip, I'm extreemly im'prius'ed with the 87.7 MPG I got. Enjoy the pics I took with my cell phone over the last 2+ miles home starting with when my milage peaked and the traction battery started to recharge.
Gross estimate, the 800 foot drop saved you 300 meters * 2000 kg * 10 = 6 * 10^6 joules, or 0.28 kwh. A gallon of petrol is worth about 12 kwh of energy at the shaft, so 0.28 kwh is 0.023 gallons. Almost there ... You used 14.3/87.7 = 0.163 gallons of gas. Without the help in declination, you would have used 0.023 + 0.163 = 0.1853 gallon, which works out to 14.3/0.1853 = 77.17 mpg. Cool! Wait for a real engineer to bless the calc before crowing.
Report back when you have driven 400 miles with this tank. I can achieve over 99.9 mpg for the first 10 miles after fill up by using EV mode and going slight down hill like you said.
Re-check that joules to kwh conversion. My original rule of thumb was 1 gallon per 10,000 feet, so an 800 foot drop would save 0.08 gallon. That would put his 'flat' mpg at 58.8 mpg. Some months ago Ken from Japan, Bob Wilson, and I compared measurements for fuel vs. elevation change. I don't think any of theirs were more than 20-30% different than mine. We'll have to dig up that thread. One of my best results was this, though it also involved a substantial drop in elevation. The really good GenII drivers can beat this on flat ground.
Brain fart -- I decided that one Kg is 1.5 pounds. A more accurate (and minus calculator error) potential energy gain is 275 meters*1400 kg*10 ms^-2 = 3.85 *10^6 Joules = 1.07 kwh. This is 0.089 gallons at the driveshaft, close to fuzzy1's estimate.
LOL! A few of us could probably be in that Intel commercial where one engineer converts a minus to a plus ... and the rest of us roll on the floor laughing our asses off ... while our better halves roll their eyes. <GRINS> Bob Wilson
After the return trip this morning, the indicated mileage returned to something more like I expected, 66.0MPG. That is still more than 50% above the 40-41MPG I was getting with my Honda Fit this time of year, so I'm tickled pink. I am really suprised that a 800' or so change in elevation could result in that much of a milage gain, or loss over 14 miles. I guess my milage back up the hill was only about 45MPG. Thanks for your helpful info SageBrush and fuzzy1. Thanks for your insite, but with only a total of 160 miles on the vehicle, that is not yet possible...Period:
You must drive on a complete flat roads and lots of down hills to achieve that mileage. I thought I was doing good with my first tank (240 miles) @ 49 mpg.
I can remember geting similar results when mine was new and the first great feelings it brings. It is very hard to keep it at that level as your mileage progresses. But it "IS" a lot of fun trying.
Thats great mileage, but up here in colder climates with Ethanolized gas, those figures are close to impossible. I got over 57 MPG, calculated by miles driven and gas used, in September. Our last tank was only 47 MPG with colder days, wet roads, and winterized/ethanol gas. Also I believe you have gas with no Ethanol, which will easily get you 3-5 MPG's more. It sure is amazing the amount of difference people are getting in MPG, you will never see that difference in regular cars. alfon
Your numbers are obviously very impressive. Not that I am doubting but, I am curious how you are getting these numbers. Could you please describe your driving procedures for the rest of us 45 to 47 MPG (on average) people?
Proof ? Energy calcs certainly don't support your assertion, since with E10 you are only diluting the total energy content by ~ 3.3%
I'm not going to check your numbers or conversions, but I do believe that you neglected to include efficiency losses, which are quite substantial when dealing with an ICE gasoline engine and all the mechanical and air friction losses of the vehicle. The efficiency losses would theoretically result in added fuel savings for the fuel you didn't use due to elevation drop.
Which numbers to you want to get? My 84.6 picture was a response to the VW TDI Tank Wars challenge. To replicate that, I suggest: (1) Wait until warm dry weather returns; (2) Find some non-ethanol fuel; (3) Fully inflate your tires; (4) Drive to the top of a mountain; (5) Reset the Trip meter; (6) Keep your speed down; (7) Take it from there. If 50-55-60 MPG numbers are sufficient, I would start with these links. First, here on PC: New Owner? Want MPG help? Read this first. After that, try the Basic and Intermediate methods from a Hypermiling site: Beating the EPA - The Why’s and How to Hypermile Pulse and Glide plus Warp Stealth in the Prius II However, if your local traffic culture requires speeds above 65, then you may be stuck with your current MPG.
Thanks for all the encouragement, guys. And yes, we have a 10% Ethanol blend from Oct - March, for whatever that is worth. Fstr911, I wish I had a magic bullet to tell you about. I almost always get to 18-20 MPH from stops on the torque battery before the ICE kicks in. I also learned very quickly that while watching the ECO meter, if I keep the bar on the left of half, I can stay on torque only. Yes, it takes longer to accelerate, but I don't care. There are always 2-3 lanes so trafic that just has to go zoom zoom can pass. When I am using the ICE and the torque is charged, I found that after reaching 40-45MPH, if you release the accelerator for a moment and allow the mileage meter to reach ~100 MPG and then slowly depress the accelerator, you can maintain your speed, with the ECO meter on the left of the middle, and continue to run on the torque battery. I guess what I'm trying to say is that I really concentrate on using the torque as much as possible. Of course watching traffic to minimize slowing/stoping and to maximize coasting when reducing your speed is inevitable also helps. I really practiced that as well as turning the motor off when coasting to stoplights with my old Honda Fit. That's how I squeezed up to 42+MPG per tank full in a car that's rated 29MPG for city. That was a GREAT selling point to me on the Prius. When I came to a stop, the motor turned off automaticly. It just feel good to be in a car that has no motor running, no fuel waisted, at a stoplight. Not that I'm any kind of expert hyper miler, an amature at best, but streaching a gallon of fuel, for me, is addictive.
fuzzy1, Thanks for the links in your previous post. In reading the pdf linked to, are the numbers used in the warm versus cold temp milage factual or hypothetical? E.G. a 10% drop in MPG with a temp drop brom 72F to 45F? Those are almost the exact temps it was when I did my downhill trip in the afternoon, 71F, and uphill this morning it was 45F when I got to work. Another question, the artical states that at the time, highway milage was tested for at 48MPG. Is that the 'optimum' speed for maximum MPG? Tom
