concerns about my MPG

Use the search function to find an almost unlimited number of threads on how to get good mileage. Short commutes, hills and hard braking will knock the mileage more than anything.

How does the Prius compare to the Suburban?

Another thing to consider, how close to the EPA mileage do you get in the Suburban or any other car? If your mileage is 20% under the EPA estimate in the Suburban then expect similar in the Prius. This is due to the type of commute and terrain as much as your driving style.

Don't use B gear and judge traffic to avoid braking.

 

CaptJB, welcome to the "guess gauge".

"We are constantly watching how we are driving and trying to drive as slow and use the engine as little as possible..."

IMO slow driving isn't the key to high FE. Accelerate briskly to speed. A rule of thumb is that instantaneous mpg should be half the speed.

 

Hi there, welcome to the Prius Cult...ure.

You have a new Prius. It takes some time for the car, and the tires, to get broken in and yield best mpg.

You are also trying too hard. Use the first thousand or so miles to just get used to driving the car. Over all kinds of terrain, in all kinds of weather.

Spend some time perusing the forum threads, especially the ones that pertain to mpg hints and tips, and try some deep breathing and other relaxation techniques.

Bonus tip: After the car is warmed up (about 5 minutes of driving), pull over and come to a complete stop. Sit for about 7 seconds, until you feel the ICE shut down. Now, the car can "glide"... pull back out and see if that helps a bit.

 

Read this article: "Why don't I get the EPA Mileage?" by efusco

 

I might be missing something but how could you put 11.4 gallons into one fill. I think the Prius has a 10.9 gallon tank, and as any Prius owner will tell you, putting in more than 9 or 91/2 gallons is nearly impossible because of the way the internal bladder works. I think you got hosed at the station.

 

Hello,


my 2 cents: A friend of mine owns a 2005 Prius which consistantly gives him 43mpg as calculated by hand. He also tells me that the computer tells him it's up to 5mpg more than that so i'm guessing the computer isn't the most accurate so I would always go with the hand calculations but I'm shocked that you're getting such low MPG's, especially living in Florida. Perhaps it's because the car is new? My personal hybrid is the Civic Hybrid 2 (2008). I've filled it up three times and had; 45.1, 46.4, 48.3 for my first three tanks but my computer consistantly gives me and underestimate of approximately 2mpg--go figure. I think a realistic MPG for the prius is around 43/44 so you're not far off...just give it some time and check back!

 

Do you guys in the USA have a message something like this on the EPA mileage sticker;
This fuel consumption is for comparison purposes only, actual consumption may vary depending on driving style and traffic conditions.

If you compare the car you drive now to the EPA numbers, you can expect to get a similar percentage of this consumption from a Prius. If your consumption in a Hummer is 75% of the EPA estimate then expect to get 75% of the EPA estimate from your Prius.

 

Yes.

 

I think the computer also calculates the time the ICE is off at stop lights.

 

The main questions here is:

how long is your commute? and how fast do you drive?

Also, how many "50kw regen" symbols are you seeing in your consumption display? If your showing more then 4 symbols, then your braking too much (in my opinion, which should equal to about 55-60mpg).

I don't have any pictures of my recent consumption screens, but the below is what I would expect in an average 30 minute commute if your using all the techniques (your commute may vary):

http://i11.photobucket.com/albums/a199/Bobc64/prius/100_1411.jpg

 

Hi CaptJB,

I think you might be one of the granny driver poor mileage people. In humid warm air, which has lower density than cold dry air, you should be getting over 50 mpg on trips over 15 miles long with peak speeds under 65 mph. Unless you are in stop and go traffic (like 100 yards at a time or so). As the tires break in (assuming they are not larger than the stock size) and the mechanical parts wear to each other, the mileage will improve.

Accellerating very slowly will kill your mileage in a Prius. Do not try to stay on electric. This is not an electric car, and it was designed for normal driving, not as a neighborhood vehicle. After running the car for 10 minutes or so, and its nicely warmed up, accellerate moderately (or a little quicker), up to speed works best. If you see a red light off in the distance try to go for a glide (no arrows on the screen). Then just coast to the light. If you need to hold speed below 40 mph and its slighly downhill then feather the accelerator peddle for electric glide (yellow arrows). If its really steep, and the desired speed is 40 mph or less, you can feather the peddle to get no arrows all the way down the hill, but you may need to lift it and get some regeneration (green arrows) to avoid going too fast. If its slightly to steeply up hill push the peddle further so that the engine comes on.

If your cruising between 40 and 55 mph, completely come up on the accelerator peddle every once and a while, and then depress it again slowly, just to the point where the car maintains speed. This will become natural after a while as you drive the car in synchrony with road loads (up hill, down hill, coasting into a stop, etc). The Prius seems to use an overly pressed peddle as an indication the driver may want to accellerate quickly, and it configures the drive train accordingly, at the expense of fuel economy. It can be very supprizing how quick it will react when one drives like this. And it definately takes a while to reconfigure things if its in a high mileage configuration when quick acceleration is commanded. The amount of peddle travel between a high and low mileage configuration at the same speed is about 1/3 of an inch, I guess.

For best highway mileage on relatively flat terrain the cruise control works good for newbies.

Regarding the gas tank, if there is large variations in temperature from morning to afternoon, try to fill up at the same time of day or temperature if your trying to guage your gas usage by pumped gallons. As the rubber gas tank bladder changes capacity with temperature.

 

What tire pressure do you use? Many people run the original tires at 42/40 PSI front/rear and get a noticeable improvement in MPGs at the cost of a harder ride.

In any case check tire pressures at least monthly. And, if you do use higher pressures, check them immediately after you take the car to a dealer for maintenance. Service techs very often reduce the pressure to Toyota's recommendation.

Expanding a little on the green cars point: there are unavoidable energy losses in charging and discharging a battery, so you want to avoid regeneration as much as possible. Coasting is better than regenerating, and regenerating is better than braking.

 

DITTO. Tire presure makes a big differance And do not go over 65mph on your 1500 mile trip. please post the results when you get back.

 

My old "WELL" used '02 would get me 50mpg day in and day out. I came to expect it and think I got that by learning how to drive the Prius. However, my new '08 gets no more than 47mpg avg. I am waiting for it to become "broken in" and I think mileage will be better when everything "rolls" easier. At about 3,000 miles, I made a round trip to Clovis New Mexico from Little Rock, Arkansas. About 11 hrs each way. I always drove at the speed of the traffic.... over 70mph and got 46mpg going (with a tail wind) and 44 coming (with a head wind). Also, I filled up two times on the return trip at a Pilot which uses a 10% alcohol blend. I think the decrease on the return trip was due to the change in type of fuel. After returning to local driving conditions (20 mile round trip each day) I am back at a solid 47mpg again. Nothing much more to contribute except to deliver my experiences on a 22 hour road trip. BTW... we sell English Bulldogs and offer to deliver within reasonable distances. Here to Clovis was on the outer limits of "Reasonable".... jf

 

Someone else may have already said this, but if they did, I missed it. The U.S. version of the Prius has a bladder in the fuel tank which causes the usable volume to change with temperature, age, phase of the moon, and sexual orientation. You can never safely assume anything about the actual usable tank volume, other than it will be somewhere between nine and eleven gallons. I usually figure on ten gallons as a nominal capacity, but then I don't like unpleasant surprises. This means that your manual mileage calculations are fairly worthless. Don't bother dividing out the miles and fuel, because you don't really know the actual amount of fuel. Manual calculations can be used over a large number of fills, since the error will average out, but don't try it on one, two, or even five tanks. It will make you nuts trying to figure out the discrepancies. The MFD does a fairly good job with mileage, so use it over the short haul.

Let me also second the advice about avoiding electric driving. Driving in the electric mode is very inefficient. Think about what has to happen for you to use electric power: 1) The gas engine has to burn fuel to make electricity; 2) The electrical energy is converted into chemical energy stored in the battery; 3) The chemical energy in the battery is converted back to electrical energy; 4) The electrical energy is converted to mechanical energy by the electric motors. Note that you lose energy in every one of these steps. It is far more efficient to go right from the gas engine to the wheels. So why have a hybrid system? The answer deals with real world driving. If you could only drive at one speed on flat roads and never start or stop or go up hills, then a straight gas mechanical system would be more efficient. The hybrid system lets the gas engine operate more efficiently as driving conditions change: The engine can shut off when stopped, run at the most efficient RPMs, and be sized for average driving conditions instead of peak loads. In addition, the hybrid system allows for recapture of some braking energy.

What this all means is that you want to avoid driving in electric mode as a general rule. Obviously it makes sense when moving a short distance in a parking lot, or creeping forward in heavy traffic, but there is no advantage and some disadvantage from trying to force it. Let the car do it's thing. The Prius control system is pretty smart, and generally does a better job that a new Prius driver. Just drive it and enjoy.

Tom

 

New car break in period, tire pressure and driving style. Take some time driving while watching the screens. Even though you live in Fla you could safely block the top two slit in the grill which would allow the car to run warmer. If your trips are short, you will never get the car warm. It takes us 10-15 miles for the scan gauge to get to 185f, the bare MINIMUM TEMP for fuel efficiency.

Icarus