winter gas mileage

http://priuschat.com/forums/gen-iii...mileage-gets-worse-in-winter.html#post1411488

 

:welcome: it is typical and it's because the engine has to stay at a certain temperature and also to provide heat. look into grill blocking threads or block heaters. all the best!

 

That seasonal swing has been typical for me, also in MN.

Here's my results (measured at the pump, which is lower than on the display) from last year:



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This graph show my seasonal variation over two years, without any tire change, in a milder winter climate than MN, and with fairly light use of winter heat:

 

Actually that nearly mimics my FE with similar situation. My winter average is closer to 43-45.

Welcome aboard by the way... sit back and enjoy the ride.

 

I just got a used 2011 (hasd a 2010), and I am struggling to get to 40mpg on the first tank. I am beginning to wonder if the mpg calculation on the computer for the 2011 was recalibrated or something. Hopeully it will increase.

 

http://priuschat.com/forums/gen-iii...-answer-these-questions-esp-if-youre-new.html
http://priuschat.com/forums/gen-iii...mileage-gets-worse-in-winter.html#post1411488

 

Why would you get a used 2011 after owning a new I assume 2010? They didn't change anything from 2010 to 2011 model year.

 

A couple of reasons. I bought the 2010 used and ended up putting more miles on it than I anticipated and it was over 40K. Also, I had someone get sick in the car and could not get the smell out entirely, even after spending $100 for an interior cleaning/shampoo - which they did twice. The trade difference was basically retail to retail, so I really did not loose much value. There was no loan on either car, so that was not a factor. The 2011 was also used (a dealer loaner) and had a little over 5K miles and is certified.

 

ScottN, you could be seeing the winter impact. On a warm day, get the car out beyond warmup cycle and use trip B to see if it gets 50+ in better temps. You really should look through cwerdna's checklist/questionaire. You didn't mention your tire pressures, your driving patterns, etc.

My worst tanks are right at 40 mpg in dead of winter with our short 1.5 mile commute legs weighing heavily. Annual average 50 even in spite of that commute distance.

 

ScottN,

Take a look at WerdnaC's link to the fuel mileage questionnaire, it will help folks try to help you out with fuel mileage questions/issues. It stems the "thousand response" syndrome where one person will ask about you tire pressure, another asks if you're in B mode, another asks about your previous car's EPA estimate vs current estimates, your commute distance, etc etc etc.

Post it up and let us have at it!

 

On my V5, mileage is always optimistic and optimally high when taken from computer. Real world mileage is no better than 30 mpg average. Toyota says it's the weather, I say bull. I achieved 35 mpg with my wife's Jetta last week end on a round trip from Lansing to Detroit. The Jetta is a 2012 w gas engine and has roughly the same miles driven as my Prius.
So when Toyota says it's the weather (which for Michigan has been unseasonably warm), I say then how is a Jetta beating a Prius in mileage in exact conditions. Toyota shrugs and says "I don't know!"

 

- Have you read This Thead Yet?
Yes

- What fuel economy are you getting and how are you determining fuel economy? (trip computer or manual calculations)
Barely 40 using the trip computer. I always used the trip computer on my 2010, so I am comparing apples to apples.

- What fuel economy are you expecting and why?
Last winter, in my 2010, I was getting 43-45 and the weather was colder.

- What are the approximate outside air temps?
In the morning it can range aywhere from 10-20. In the evening, it has been around 35-45.

- How long are your trips?
My daily drive to work is about 10 miles each way. Probably not ideal for the best mileage.

How old is your 12v battery? What is the voltage reading of your 12v battery after sitting over night? (Method Here)
I have not checked it, but it is less than a year old with 6K miles.

Have you had your alignment checked? Any pulling or abnormal tire wear?
I am having it checked today. There is no pulling or abnormal tire ware, but the center steering is off.

- How much of it is city vs. highway? Roughly what's the average speed in overall and and of each segment? Is there a lot of stop and go driving?
It is probably 6 miles highway (50-65MPH), and 4 miles city (stop and go 35-40MPH).

- What's the terrain like of your drives? (e.g. flat, gentle hills, steep hills, etc.)
A couple of steep hills. The highway portion is relatively flat.

- What are your tire pressures?
I still have them at factory spec 35-33.

- Is your oil overfilled? (i.e. above the full mark on the dipstick)
Maybe just a tad.

- Make, model, year, engine and transmission of previous car? (e.g. 08 Honda Civic Si 2.0L 4 cylinder, manual transmission) What did you actually get on the same trips/commute? (Please give us actual numbers, not EPA ratings.)
2010 Prius. Last winter I got closer to 45.

- What region/state are you in? (if you haven't set your location)
Omaha, Nebraska

- How are you trying to drive (e.g. trying to stay in electric only?) and how hard are you braking?
I try to stay in electric mode as much as possible, but there are a couple of steep hills where it is almost impossible to stay out of the power band when there is traffic. As far as breaking, I try to break a little harder at fist and then lighten up to recharge the battery.


- What modes are you using, if any? "normal", EV, power, eco?
I alway use ECO unless it is so cold I need it to warm up faster or when the wife is along

- Are you "warming up" the ICE (internal combustion engine) by letting it idle after powering on?
No, unless you count going 20-25 in the neighborhood the first mile or so.

- Are you driving using D or B mode?
No

- HVAC settings? Are you using the heater, AC, auto mode, etc.? If using auto, what temp is it set to?
I use the auto mode and depending on how cold it is, I set it up higher to maybe 76-78. Once the cabin warms up, I usually set it back to around 72.

- Are you using the factory tires and wheels? If not, please indicate tire make, model and size (e.g. Goodyear Assurance Fuel Max 185/65R15).
Yes, factory Bridgestones.

- If reporting a mileage drop, did anything significant change on your car (e.g. accident, hit a curb or big pothole throwing off alignment, oil change/other maintenance/repairs, changed tires or wheels, etc.) or your commute?
Can't say for sure since I have only owned the car for about 2 weeks.

 

You have not compared exact conditions in the least. Use the VW as your daily driver, then compare.

 

My 2 cents:

New 2011. Up to 720 miles now.
As the temp moved from 20-40 deg now up to 60 deg, my MPG avg on my daily commute has gone from 46 to 49.

 

It's not the number of miles driven but the type of driving conditions experienced that matters. Both the Jetta and the Prius must be driven under the same exact conditions (e.g. a week end round trip between Lansing to Detroit under the same driving conditions/ weather) to make a fair comparison. If both vehicles were driven at the same time from Lansing to Detroit - their MPGs would be likely be similar.

A Prius get its best fuel efficiency when driven longer than 60 minutes/10 miles per trip and rarely get their rated FE when driven less than 10 minutes/2 miles per trip - this is because fuel efficiency is not a Prius primary design objective. A Prius primary design objective is not to pollute the air. Hence, the Prius will heat up the catalytic converters to get the cleanest possible emissions at the expensive of fuel efficiency. The prius secondary design objective is extend the lifespan of the battery and it will attempt to maintain a charge on the HV to extend its lifespanat the expense of fuel efficiency. Its only after those two design objective have been achieve that the Prius will optimize its fuel efficiency.

A 2012 Jetta energy efficiency performance is more straight forward; it has no HV battery to worry about and it doesn't go through any particularly special effort to reduce its emission levels.

The Jetta doesn't have auto stop idle technology so its going to burn gas when its waiting in traffic - the Prius v has auto stop idle technology and will not burn gas when its waiting in traffic.

At speeds between 15mph to 35mph, the Prius v with its electrical power assist should be able to coast/glide signficantly further than a conventional gas Jetta which in turn should give it a fuel efficiency edge in low speed rural -suburban driving environments.

 

Was your 2010 also at this pressure, or was it higher?

I keep electric mode to a minimum, to avoid its energy conversion-reconversion penalties whenever practical. Going uphill, much of the power band seems to cost very little in overall fuel penalty. But if you can avoid the harder braking by starting a bit earlier, or even coasting/gliding earlier, that should help.

For forward motion, you need one of these. D is the correct gear for almost all use. B never helps mpg, and is probably unnecessary in your state.

This costs some fuel. Did you use the same settings in the 2010?

 

I kept the tire inflation the same on both the 2010 & 2011 - 35-33.
I always try to avoid hard braking, but will try to be more careful with that.
Sorry, I always use the D mode.
I use the HVAC the same as I always have. Anys suggestions here? Our temps can run anywhere from 0 to the 50's.

Lately, we have had very warm weather for this time of year, with the average high in the 50's. I have really been watching my driving habits closer and am now all the way up to 42-43!