City Mileage 10 MPG worse than Higheway Mileage

I never read anywhere that city mileage would be better than highway.
Highway driving usually means little acceleration, so to maintain constant motion requires less energy than stop and go.

The energy you get back coasting and regenerative breaking is only a tiny fraction of what was used to get up to speed. The Prius isn't a In-Wheel Electric. The In-Wheels recoup a much higher % of the energy while breaking.

What's interesting is how little driving at 55MPH, 60 or 65 makes the gas usage differ.

Makes you want to always drive at 65mph...

 

Your mileage sounds low to me. I don't understand the part about the battery getting low while parked. If I have green bars when I shut it down, that's what I have when I start it back up. I do notice low mileage for the first 5 or 10 minutes when the engine is cold, but in low speed (under 40MPH) stop and go, the engine is off a lot, unless it's 90 outside and a sunny day, in which case it runs more, but my city always seems higher than my highway.

 

<_< karat...

Your Prius is not "warmed up" or "broken in" yet. There's also a "learning curve" on how to get the best fuel economy. The Prius is a "different" car and while you can "just drive it," you can develop driving habits which will improve fuel economy. Many new Prius drivers report their best MPG results begin at somewhere between about 6,000 miles and 10,000 miles after wearing the moulding "nibs" off the new tires and limbering up the mechanical systems. Some Prius drivers believe that overfilling the motor oil can reduce fuel efficiency, and dealers frequently do overfill. Another fuel-saving technique is keeping the tire pressures higher, I run mine at 40 psi front and 38 psi rear. The 10 MPG difference between highway and in town are almost exactly what I experience after two years and 21,000 miles. Around town (mixed short and intermediate trips), I'lll do about 45 mpg, steady freeway at 65-70 MPH, I will do 52-55 MPG.

The EPS estimates are made under strictly controlled "laboratory" conditions and don't reflect "real world" driving conditions. For fun, read the language on the window decal - just below the "60 - 51" numbers.

Enjoy your technical marvel Prius, the most advanced production vehicle available.

 

<div class='quotetop'>QUOTE(Mark Derail @ Oct 2 2006, 04:36 PM) [snapback]327102[/snapback]</div>

It is EPA rated at something like 60 city, and 51 Highway.

I see around 50 on the highway, and 55 on my commute, or better, depending on the amount of stop and go and the weather (AC usage). I've seen 70 MPG on some trips, but that's with a traffic tie up and lots of stop and go, and very little over 40MPH. The engine runs just enough to charge the battery, then the car stays in electric mode until the battery droops.

 

Your problem could be number 4. You said short trips 10 to 20 minutes, the 1st 5 minute I only got about 25 to 30mpg. The next 5 minutes about 30-40mpg, but 10 minutes and if I pulse and glide in the city I should get about 60 to 75 mpg.

 

I've got just slightly under 2000 miles on mine and also see lower mileage in town, mostly suspected to be due to not yet broken in and definitely shorter trips. Fremont OH is a relatively small town and it doesn't take long to go from place to place so much of my in town driving is short (10 - 20 minutes) but I don't see any where near the 60 - 70 - this gives me something to strive for. I probably average about 45 mpg in town, and have been averaging 50 on longer drives to work. Have not noticed any battery issues.

 

<div class='quotetop'>QUOTE(karat @ Oct 2 2006, 05:16 PM) [snapback]327132[/snapback]</div>

You're not driving in "B" instead of "D" or anything like that? "B" stands for engine braking, and some people reportedly think it means "Battery" or something...

Tire pressure OK? I had a slow leak, and was driving around with 25 lbs or so, and noticed a mileage drop.

I can't remember exactly when my mileage got better, but I thought I was seeing in the 50's after 2500 miles or so. I know the first 1000, I never got above mid 40's for the most part. I'd expect to see much better mileage that what you are getting, especially on the city part, assuming you are not trying to recreate the Fast and the Furious from stoplight to stoplight or something like that. Could be your trips are just short enough that the engine never fully warms up, I suppose, but if you can go for a longer city drive and see what you see on the "consumption" dispaly after 15 minutes or so of city driving. I'm assuming these are the same between an '05 and an '06. I know that for my stop and go commute, it doesn't hit the plateau until about 10 or 15 minutes in. The first 5 minutes is like in the 20's, then the next in the 30's and then it levels off in the 50's.

The part about the battery level dropping while parked, i.e., I assume with the car off, definitely sounds like a problem. I'd note that for when you talk to your service dept., that should not be happening, but without seeing the displays, it's hard to say what you are seeing.

Beyond that, and I think I know a lot about cars, not sure what else could be be wrong, or even what the average person could really check even if someone had an idea. It's a new car, it's under warranty, call your dealer's service dept. and have them check it out.

 

<div class='quotetop'>QUOTE(karat @ Oct 2 2006, 04:21 PM) [snapback]327087[/snapback]</div>

I believe the main reason is #4. For the first five minutes, I NEVER get over 25 mpg, sometimes much less. The second five minutes is more, but usually not more than around 40. Usually, even after the car is completely warmed up, after stopping for 30 minutes at a store, the first five minutes after restarting is pretty low again, around 25 mpg. On the highway, I generally get over 50mpg (even during the first 1000 miles or so), but I think it's because I take longer trips on the highway.

 

<div class='quotetop'>QUOTE(karat @ Oct 2 2006, 04:16 PM) [snapback]327132[/snapback]</div>

That sounds like you're in "B" and not in "D". "B" should be used only when going down a very long steep hill, as an alternative to riding the brakes. In Boston there is never a need for "B".

10 minutes trips with the A/C running definitely kill fuel economy. The EPA figures, which Toyota is required to publish, are not realistic for the way the Prius works. Most people find that their highway fuel economy is better.

What did you mean by the battery running down while parking? If you meant something like "parked with the car READY and the A/C on while I wait for my mate to use the ATM", then draining the battery down to two bars is normal. If you meant that you believe the car is turned OFF, as though you're leaving it for the day, then draining the battery is not normal.

 

The first five minutes is a killer for me...also, I have lots of HILLS....

My first tank of gas (I do no highway driving) was 30 mpg. Then I really maximized factors I read about here...tire pressure upped, and driving techniques...Second and third tank of gas...42, 44 mpg.

I now "bunch" my errands in one day...taking the longest leg of the trip first, if I can...that may only be a 10-20 minute drive on local roads, but the ICE is warmed up...by the time I near my first destination, I can use P&G nicely, I go into electric only (all yellow arrows) for some slight up and downhill runs...and then coming home I have lots of "coasting" (downhill ...no accelerator at all) to get regen....

This article helped me a great deal initially, although there is a good deal of information here at PriusChat.

http://www.hybridcars.com/maximizing-milea...yota-prius.html

I only have 1000 miles on my car so I am hoping to go up slightly although winter is going to set in and cold weather is the mpg enemy.

Good luck.

I ran into some people locally who also said they get roughly 45 mpg around my area. Your locale, trip length, AC use, tire pressure...all factors...but I do feel the driving tips have helped.

terri

 

<div class='quotetop'>QUOTE(karat @ Oct 2 2006, 04:16 PM) [snapback]327132[/snapback]</div>

Hiya, Karat. That mileage does sound low, since I've got 1000 miles less than your car but getting better mileage. Your car should be more run in than mine. I'm wondering about a couple of things...

1. Short trips and the engine not being warmed up. Do you have time to make a 20 to 30 minute drive and see what your mileage is like in the latter part of the drive?

2. I've never been to Boston, but I've heard the traffic is pretty scary. Is that so? Do you have a lot of stop-and-go traffic? The EPA estimates are based on longish stretches at low speed, not a lot of stopping and starting, so if traffic is like I have heard, maybe that is part of the problem. Can you test in a lower traffic area?

If I'm reading correctly, your engine is running to charge the battery until green bars are showing on your charge indicator? I can't think of a reason for that to happen in normal operation.

 

<div class='quotetop'>QUOTE(karat @ Oct 3 2006, 02:20 PM) [snapback]327408[/snapback]</div>

Yikes! My '05 doesn't do this, and I'd sure notice, since my house is on the lower side, and I can usually glide in and get green bars on my return, and it's there the next day. Sounds like a definite problem. With the car off, the "aux 12v battery" is used for smart key etc. as far as I know. Good luck.

 

<div class='quotetop'>QUOTE(karat @ Oct 3 2006, 02:20 PM) [snapback]327408[/snapback]</div>

The electric engine is about 1/3 as efficent as the gas engine. As all of your energy comes from gasoline. The estimates of efficency after charge-discharge losses from the gurus in the Yahoo Prius technical group generally is about 30%. The magic is that all the other cars throw that away when braking to a stop and then waste 100% while in idle at a stop. The guys who have set the mileage records with the Prius use the electric cycle as little as possible.

When you car is off, the HV battery is disconnected, so alarm systems, SKS, etc. can't be what is pulling it down.

I have left my car in a garage for 8 days while on vacation and returned to find the main battery at 7 green bars, just where it was when I parked it. I have seldom noticed more than a one bar drop and I attribute that to the temperature dropping overnite by 30 or 40 degrees (F) and perhaps the battery display being on the edge of dropping down a bar to begin with.

It might be worth a check at the dealer if you have a good Prius tech there.

- Tom

 

<div class='quotetop'>QUOTE(karat @ Oct 3 2006, 01:20 PM) [snapback]327408[/snapback]</div>

a drop of that amount overnight, with the car turned off, is serious. take the car to the dealer imediately. The hybrid batteries are disconnected from the rest of the car when it is turned off, and thus shouldn't lose any charge overnight. Of course, if you're right on the edge and it gets extremely cold, you might see one bar disapear, but thats it. if it's going from green (top 2 bars) to pink (bottom 2 bars) when off, there is a serious problem that needs to be diagnosed and fixed - under warrenty.

And to answer your side question, it's a bit more complicated. Assuming a limitless amount of energy for the electric motor, it is cheeper at current rates to drive on electricity than on gasoline. However, without the ability to plug in the car to recharge much larger batteries, this isn't so. Whenever the ICE runs to recharge the batteries, energy is lost in the conversion. More energy is then lost when running the motor. so you are essentially penalized twice for that energy, where as the same distance traveled by using the ICE directly you're only penalized once.

The most popular method for driving is pulse and glide, where one tries to accelerate the car while putting the ICE in it's optimal effeciency range (about 70% RPM, but with no tachometer it's hard to tell), then easing up and gliding with no arrows on the MFD down again, and repeating. to get no arrows on the MFD, you have to feather the accelerator a little bit. Of course, this strategy shouldn't be employed at high speeds (anything above 40 and the ICE won't turn off, thus the idea of warp stealth to "do your best") or in traffic, as it creates a potentially dangerous situation.

 

<div class='quotetop'>QUOTE(prius biker @ Oct 2 2006, 05:49 PM) [snapback]327148[/snapback]</div>

Same here in Bowling Green, Ohio... Similar sized towns, terrains, climate, etc... (FYI Fremont is about 28 miles east of Bowling Green in northwest Ohio, both are on US route 6)



Im at around 10,100 miles and driving from Bowling Green to Port Clinton I can get up to 52 MPG with careful driving in summer weather... Routinely making trips from BG to Findlay and Back on I-75 I average 47-49 MPG on the highway at 60MPH (higher if I can draft a large truck, at a safe distance of course )