51MPG is for city, not highway, right?

The Prius does better on the EPA city test than on highway test. That doesn't mean it will necessarily do better for you in the city. Car makers can only supposedly advertise EPA numbers. (The only time I've seen company seem to violate this was VW w/some online ads for their TDIs where they quoted some other higher figures on non-EPA cycles, first and in large print. Unclear to me if it was illegal and if they were penalized for it. I posted about it at http://priuschat.com/forums/other-c...di-ad-advertising-non-epa-method-mileage.html.)

For more info on the EPA tests, see http://priuschat.com/forums/other-c...uth-about-epa-city-highway-mpg-estimates.html.

Here's what CR got in their testing: Most fuel-efficient cars.

The other problem is that winter conditions and will hurt your mileage in any car. See:
Why does mileage drop in winter? — Autoblog Green
Cold Weather Vehicle Fuel Mileage – Why Winter Fuel Economy Drops – Fuel Mileage Drop in Vehicles
Car Talk
http://www.startribune.com/cars/11354696.html

If you want fuel economy help, answer the questions at http://priuschat.com/forums/gen-iii...-answer-these-questions-esp-if-youre-new.html. May as well do it as a reply in this thread.

Without much other info, your tires could be underinflated and you could benefit from grill blocking in colder weather along better heater usage and driving techniques.

 

7 miles a day, meaning 3.5 miles each way? If so, the short commute is hurting your mileage.

 

Highway basically represents cruising along at a high speed.

City means "not highway", pretty much everything else.

Your encounter with "city" is an extreme. All those starts & stops, at slow speed, with so few miles per day isn't all that the category includes. The engine never has a chance to warm up and the demands of acceleration are heavy.

For those who don't have "city" driving like that, in other words "suburb" encountered, we see MPG dramatically higher. Being able to get the vehicle up to speed around 45'ish and maintain that with a warm engine for awhile allows the hybrid system to thrive.
.

 

:welcome:You don't drive far enough during your commute for the ICE to warm up. Grill blocking may help but don't expect much - again short commute. When you get the chance to take it out on a longer trip - maybe on a weekend - you'll see after it's warmed up how your instant mileage will improve. Read everything about tire pressure, P&G and other driving techniques (within reason for your traffic conditions) and you'll see an improvement.

 

Like the others said, it's your short commute that's bringing the numbers down. The Prius starts out with pretty low mileage (18 or 20) for the first mile or two and then works it's way up over the rest of the trip. If you're only going 3 or 4 miles in a trip, then you're probably getting much better mileage on the second part of your trip, but the first part is killing your average.

You can see this by changing the display to the one minute average consumption... keep hitting display until you get to the 1 minute or 5 minute average screen, then if it's on the 5 minute average, hold the display button until it switches to 1 minute. Take a look at that screen after your commute and I would bet that the first minute is around 18 or 20 and the last minute is a lot closer to 50 or 60, with it quickly going up between the first and last minute.

Also keep in mind that all cars do pretty poorly as they start out... even a non hybrid car with a window sticker promising mid 20's in the city would probably be down in the teens on your commute... it's just the curse of a short commute.

The other trick I do, although I don't really know how much it helps is to immediately put the car in EV mode as soon as I turn it on. Since the engine is cold it won't let me go over 10MPH without turning the ICE on, but at least that lets me get out of my garage and most of the way out of my neighborhood without turning the ICE on... then when it does finally turn on I'm using it to drive the car as well as warm up the engine. Before I started doing that it would turn the ICE on to warm it up as I backed out of my garage and as I was driving out of my neighborhood at 8MPH it always killed me that it was using gas and not doing anything useful... at least this delays the ICE start a bit until I need it anyway.

hope this helps,
Brett

 

I doubt the OP will see much improvement with such a short (3.5 mile) commute.

Ken@Japan recommends idling until Stage S1b, because the Prius would run on battery power so there's no advantage to driving around during this period of time in terms of bringing the engine up to operating temperature and acceleration using ICE isn't possible until Stage S1a is over.

 

It's the short commute like everyone said, but just remember you're nonetheless probably putting in less than half the gas you would with almost any other car.

 

Practical data points from a guy who doesnt practice any fancy hypermiling:

This Christmas, San Francisco to Corvallis, Oregon, and back: 51.1 on the dash display, with winter gas (obvously), driving the speed llimit on I5, where the highest pass is only 4000 feet.

Rest of this winter: local driving averages 46-47. I can see the mileage ratchet up quite a bit if I have to go to San Jose on 280.

2010, bought last March, 12,000 miles.

Used to do the Christmas drive in a 2001 Outback. Averaged 30.

The highest steady-state mileage I've ever seen was 63, in summer, doing a steady 45 mph on the levee roads between Antioch and Sacramento.

 

I do agree that at low speeds the car will run on battery power while the ICE is warming up as evidenced by the times that I don't put it in EV mode when I start... even with the ICE running I'll lose a bar or two on the battery meter as I slowly leave my neighborhood.

However, I don't agree that it's not possible to use the ICE while it's warming up. When I do put it in EV mode first thing and then let it take itself out as I accellerate past 10MPH on the main road I can put the HSI toward the right side of the display and even into the power bar and the car is definitely using the ICE for accelleration, even though it just powered on at that point.

Now, even though that is possible I don't know that it really is more economical... it just makes me feel better Maybe I should do a couple of tests over several mornings and see if I can determine which way is better.

 

Ken@Japan also confirmed it's indeed possible to get it to use ICE while in Stage S1a if you push it hard enough, but don't rely on the display as it's telling us a lie. So if you're driving on battery power in EV, then hit the onramp to the freeway you'll get ICE to kick in; however, it won't happen during normal driving assuming you start normally. It might make you feel better, but you're just delaying the inevitable and it can't be energetically efficient for it to use ICE before it's warmed up.

 

I have had entire winter tanks in the high 30's mpg on my 1.5 mile one-way commute plus misc local driving.

But for the year with better weather and more warm engine driving, we average just over 50 mpg.

So take heart. But also, up your tire pressure, block the lower grill, improve your anticipation of lights to avoid complete stops, make sure you understand gliding instead of coasting, limit climate control usage (I figure if I have a short commute, there is no point in getting the car all toasty), etc.

 

This is interesting. I've been wondering what 'normal' drivers get in a Prius, to compare with my 1969 Rover 2000 retrofitted with 1994 Land Rover 300Tdi diesel and 5-speed box (no electronics or fancy gear). That's avearage 41mpg (US gallon) over about 20,000 miles. Best actually measured was 45 mpg at 50 - 55 mph, fairly flat rural road.
So my fuel cost overall (on diesel) isn't far off what yours would be here (Canada).

 

There is much more to it than you are telling otherwise those #s are not really possible in average situations.

 

Yep. Concur with all the others. Short trips like that will absolutely kill mileage and the cold weather makes things even worse.

I didn't read the post carefully at first and thought the OP's trips were 7 miles. :redface:

Notice that on the EPA tests that the only tests run on a cold engine simulate 11 miles each and are 31.2 minutes long. They don't run the tests on a real road nor do they measure fuel usage but rather tailpipe emissions.