Mileage

Good question...the post said something like you use the on screen MPG and add a certain amount like say you're getting 40 MPG., add I guess some magic number...

 

I find 45MPH is the sweetspot for highest MPG.
You're doing great for those speeds in my book.

 

Boy oh boy!!!

I actually believed the dealer when he said they checked the tire pressure at the 5K mile checkup. Boy was I naive! And I should have NEVER waited 8900 miles to check it myself! Because when I did, I found the pressure on all four to be only 35 psi. I bought one of those dc powered air compressors that many of you carry around in your trunks. Unfortunately, the gauge that comes with it isn’t graduated very accurately. So I set it for 45 and pumped up all four tires.

WOW!!! I immediately found the mileage to improve. My reports for this tank should set personal best records. I am already over 55 mpg when I used to average 47 if I was lucky.


PLEASE! PLEASE!! PLEASE!!!

Get an accurate tire gauge, and check your tires. Keep them inflated, and pay attention to them. This is the one most significant thing I have done to improve mileage! Just like the old timers tell you!

-John

 

Well now I dont feel so bad. Well I didnt until I read that maggieddd got over 600 miles to one tank. I havent even been able to hit 500.

For some reason or another Ive noticed something really weird.

If I fill up my tank before its completely empty the mpg on the screen dont match my calculations. I divide the # of gallons I put into the total number of miles driven. Example 456 miles / 8.8 gallons. if I wait until its nearly empty then my calculations nearly match what the screen states.

I was in the high 400s per tank but now I am barely getting 400 even though it states Im still getting 40+mpg.

What gives?! :cussing:

 

Well do the math, ReneGS and also try and be consistant on HOW you fill up. If you barely get 400 and yet only put in 8.8 it is better then 40 mpg. But the pumps and bladder system act different each time depending on weather, and gas station pump settings or sensitivity. I usually try and fill up at the same pump and same gas station, I fill till it clicks off on pressure, pumping at a slow setting, or low rate near the end of the fill up. Usually I get 1.5 to 2.0 gal more, by VERY slowly topping off, ONLY do this if you are going to use gas up driving, if you just drive home and park that could cause minor problems. The thing to do is to fill up with a "system"., fill up each time topping off, and near the same time of day, usually nightime is better. Try and use up a little gas ie run some where so as to avoid a full tank and expansion if weather warm up occurs, otherwise fuel can come out of the tank bladder. I find the screen values close to the actual mpg calculated, and I always reset mileage A and B myself, although the car is supposed to do it automatically. I usually write the screen miles and mpg, and fuel quantity added and trip miles, as well as the ODOmeter. You can get 600 miles and the likes, if you are in very temporate climates, note that MaggieDD lives in Boston. In the fall you should see improvement in mileage, and in winter you should get better mileage than MaggieDD. The way these folks get the 600 miles per tank, is 1) they drive the car very well and have longer trips with some stop and go, 2) they run the gas down and put in 11-12 gallons in, and "push the envelope" one day they might run out of gas! Just apply good driving habits and be patient with yourself. Monitor how you fill up and watch the tires, I plan to re-check mine, I understand you should have about 42 psi front, and 40 psi rear, Graz just noted how critical that is. My mileage has been piss poor too, best tank I ever had was 467, but I don't wait till the car flashes me to fill up., at that time I filled up and the calculated MPG was 49.9 MPG, MFD screen said 50.1

 

I still haven't broken 50mpg on my 8 month old 05. Seems like the traffic lights are always out of sync...meaning you go a half mile, then stop. Then go another half mile. Then stop. And keep that up. This is on roads with a 45 mph speed limit. On days when I am lucky and the lights really are synced, I have seen the "average" for the tank in the 50-50mpg range, but as soon as it gets back to dead stop, then go - the mileage drops to about 48. For hills, my instantaneous shows that when climbing a hill with a "smooth" pace, the mileage drops to 16 or so. If I gas it up the hill, it drops to 9, but it's only there for a fraction of the time it shows 16, then it's up to 99 on the downside of the hill. Still trying to figure out how to break the magic 50 mark, but so fare - no luck. But 49 is way better than what I was getting in my old car, so I'm still happy.

 

KCprius., mee too...just keep working at it. Stop and go is a real killer. Galaxee has excellent suggestions. She accelerates briskly w/ gas engine and then works to coast and recharge. Stuff like that seemed to have helped my car, but 50 mpg is about the same I've seen so far, got 2 1/2 months of ownership.

 

IALTMANN: Thanks for the good advice. I think the problem is that I mnight not be completely filling up my tank . Once the pump stops on its own I'll just round up the amount. Ive always done this because i dont want to put too much gas and have to lek on the paint.

Unfortunetly I cant always completely empty the tank (Not sure its really good idea anyways) since if I dont have enough gas I wont make it to work. I have a long commute and cant risk not having enough gas to make it there.

 

Glad I was able to offer something helpful ReneGS if I find out anything else I will post that here or get a hold of you via PM. Good luck..don't worry about the full tank runs, you do not want to be running out of gas.

 

Maggieddd...it this helps, at the second mark, or immediately upon going to one mark, you should be able to safely put in about 10 gallons.

 

It usually gets "full" with 9 gallons.

The last bar on the fuel gauge is usually blinking when I put gas. Ive also had the touch screen tell me to fill up.

This last time I did try to top it off and it seems like I just might get back into the mid to high 400s.

 

I believe the highest MPG can't be achieved above 42 MPH.

The 1200 miles challenge will be done between 30 to 40 MPH.
http://www.priuschat.com/forums/prius-mara...un-vt10705.html

 

Been trying to figure out this mileage stuff since day one with my Prius! And I don't have Wayne's Palm program, so I've been trying to make a very simplified table of mpg vs speed and temperature. I immediately notice two problems with it:

By not really handling engine losses properly it just shows higher and higher mpg the slower you go. The other errors I still don't get fully, but I expect it is engine related.
I had to give temperature far more effect on mpg than it would have from drag alone,
to fit my data.

I figure the optimum max mpg steady state speed would be the speed on level road where the engine runs at it's minimum rpm. Below that you would need less torque and would therefore not need that rpm, so the extra friction would be a waste as you went slower.

From the engine data I saw I thought it looked like the engine got better and better up to 70 mph or so. Based on that the best speed would be less than that at the point where the drag curve crossed the engine efficiency curve. I was guessing maybe 50 mph but it is too hilly here to measure this. So Dans 45 might be right on.

But this is all talking steady state constant engine torque, level road, no wind, etc.

There are two other ways to max mileage and they are clearly superior. My method is to max battery use. Ken and many others use pulse glide. These only work optimally below 42 where the engine can be stopped part time.

Clearly there is a loss using the battery charge-discharge. I think it is mainly the slope of the roads and traffic that makes me get best mpg with battery usage. I can't keep reasonable speeds with the pulse glide around here. And on big trips where it might work, I am on highways going too fast.

So maybe we should think in terms of 2 or 3 kinds of best speeds for max mpg?

Then there might be further effects if trying to optimize in flat areas, or in hilly or mountaneous areas.

 

Tomdeimos: do you have the EV modification?

I don't but maybe being better able to control and force use of the batteries and motor may help in getting the mileage.

I have found, and mostly I am in FLAT hot climate and SHORT stop and go trips, that firm acceleration to a working speed and glide + combination motor and recharge (thus getting the 99.9 MPG) yields me the best results. I ALSO make it an important point to come off the gas and trigger glide or re-charge when coming to or to see a red light or stop sign/situation. Never accelerate to a stop.

Pulse glide I have found is difficult to get and manage while maintaining a speed, and of course you must be going below 42 mph. You can however control things better with a combination, as you mention, so you are on the right path.

 

Yes I do have the EV button. And I use it a lot too, for things like parking lots, moving the car in the driveway, and ending my trips for the last bit before stopping. It is fun to use but I can't say it helps mpg any significant amout most of the time.

There are cases where it helps me a lot where conditions would make my mpg bad anyway, and with EV it comes out less bad. I'll give two examples:

1 In fall and spring at certain cooler temperatures the car doesn't want to use electric mode sometimes, but it is still warm enough to coax it to a bit with EV. And this can help such as when you are stopping at a light anyways, you can cut the engine earlier, where it might not otherwise go off at all, or quite delayed. This helps on my short trips
before the full stage 4 mode especially.

2 In some traffic jam conditions I can use it where the traffic is alternately going 0 mph and then quickly to like 20 mph and then 0 mph again. EV helps me keep the engine from going on and off as much while still being able to accelerate ridiculously fast for the conditions like the rest of the traffic.

For normal driving about the only time I would try to force extra battery mode with the EV button would be where I am coasting down a long hill engine off but there is a short rise that needs some power and I am under 30 mph, so I can use EV to keep the engine from cycling on unnecessarily but still get up the small hill. This case the battery gets more room for braking needed for the rest of the hill.

So when I say I maximize battery mode I am normally doing it with feathering, and letting the car do it's own thing. Just trying to help it by knowing terrain. Coasting might work better but with traffic I can keep with the flow better using battery, and these are small roads, not 4 lane highways where everyone can just whiz by me. I can generally average over 70 mpg if the lights and traffic don't force too many extra stops. Sometimes I think the engine is going less than half the trip. So I might get 5 min of 30 mpg but then 10 min of 100 mpg plus. Today I had one bar at 30 and over 3 at better than 75. Rest were in betweeen.