(Nearly) worst-case scenario mileage...

Babies require so much furniture!!!! Cool write up.

 

I mentioned in another post ... "Impromptu roadtrip..." (over thanksgiving) the wife and I had took a 1000 mile trip from Northeast Indiana down to Jonesville, VA for a funeral. basically, picking up I75 in Lima OH. down to corbin, ky then over through cumberland gap... pretty area - decent drive ... but staying up with the traffic at 75mph.... cruise on 90% the way ... on the way down, fuel calculated at about 38.9 .... driving at destination wasn't too bad, but it's switchbacks, hollers, and I'm still pndering this one - but stop lights at the bottom of long steep grades...
anyway - then back home same scenario - speeds 70-75mph ... the whole way....
all in all - overall avg. was 41. not bad considering - but we were not near as heavy - just the 2 of us and an overnight bag with change of clothes... our 3 kids (11, 7, and 1) stayed home with my folks.

It wasn't bad mileage - compared to my 20mpg 4x4 blazer ... by any means - but in july and august I was holding in the high 47mpg range.

now with temps only in the teens here - I'm seeing around 39 mpg for my commute - which is 45-60mph two lane highway (state roads) ... 45 miles each way everyday.

 

I'm new here. I've only had my Prius v for a week. I don't understand how the interior temperature set at 74 would use more fuel, especially when travelling at highway speeds. Doesn't the engine generate enough heat under normal conditions that it would be wasted if not diverted to heat the interior?

I understand that the engine would need extra fuel for the initial warm up but after that it shouldn't use more fuel to warm the interior. What am I missing?

 

Sometimes the engine produces enough waste heat for the interior, sometimes it does not. City driving with lots of engine-off time waiting at stoplights, or sitting in traffic jams, are situations particularly likely to not have enough excess heat. An engine monitor (such as ScanGauge, Torq, or several other devices / apps) set to display coolant temperature will help show the most serious cases.

But serious hypermilers have found that even non-hybrid cars get lower MPG when interior heat is used. While the difference is less dramatic than on efficient hybrids, it still happens.

 

I didn't use heat or air for an entire tank. Less than .5 mpg difference. </heatandairbackon>

 

Two things ... in the summer - running the AC ... on a hot day... yes, the motor would shut off, but - depending on the thermostat and how hard the ac is running - the engine would have to kick on to recharge the battery....as opposed to say having the windows open... and no ac.

in the winter - there is a balance I'm finding on the V -- depending on the interior temp you set and the outside or ambient temp. the engine will run longer to get the coolant up to temp ... and will also run more frequently to maintain the coolen temp... so that the fan doesn't blow luke warm air, it blows warm air. (i usually have mine set at 72)....
now, if I drop the temp dial to 68 as an example - the engine will shut off sooner and not kick back on as fast. a long light at 72 and it will almost always restart before the light changes.

then, as i pull into my driveway... if the engine is running, and i turn the heat off ... within mere seconds the gas engine will shut off -- as there is no "Demand" for heat...

it's all relative to where you set the temp - the outside temp - and the conditions of the programming.
it will warm the engine up first on a cold start no matter what - once it's warm, it will then cycle and run as little as possible to maximize fuel efficiency .... when it's cold, it's less efficient.

 

Forgive I if I am remembering this incorrectly, but I thought someone had done some extensive testing and found that driving a Prius with the A/C off and windows down can actually use *more* gas than if you just have the A/C running?
I believe it had something to do with the electric A/C motor being a variable speed type that can run at a lower speed when it's not needed as much (unlike belt-driven ones). And opening the windows causes a significant amount of drag.

I guess, "ideally", it would be best to have windows closed and air off, but I'd say that's unrealistic in most parts of the world.

 

I definitely agree with this, because I had gone from a 2002 Isuzu Trooper with 13-15mpg to my 2006 Prius, which was night/day. However, going from the 2006 Prius to the 2013 Prius v is the opposite. Not by much, certainly not like the Isuzu, but I just have to get used to sacrificing MPG for size. And coolness... the v is way cooler looking in my opinion

 

That's beauty of the V. If you "just drive" it, it will get within 2 mpg of the EPA estimates. Completely unlike another direct "competitor" that misses the EPA estimates by 7-10 mpg.

I bought my V thinking that I would be getting 40-42 mpg on my daily commute. I was surprised (after a short learning curve) when I started getting 47-52 (actual) mpg's .

 

Wow, what's your secret? I never got close to 50 MPG average in my GenII, so I can't imagine getting 50 mpg in the v (unless there's a hurricane at my back )

 

Me too. There must be something unique to the Al from WA poster's commute. My mileage is mixed from local 25MPH to 75, stop and go, a half mile to on the highway for 150-200 miles non-stop. I drive in ECO mode and you see from fuelly I don't break 40 on average with a best early on at 43. Not significantly disappointed as my prior cars got 20-26 on those same paths with premium gas in some cases. Half the time I drive gently and other times I just drive.

I know one aspect is that Al has had his a lot longer so he had more summer driving where I had none. And his is well broken in where mine has but 3,500 miles on it. But does that explain 10MPG? I don't think so.

 

Mike, Soylent:

The secret ingredient to the secret mpg source is.....

Wait for it....
Wait for it....

SPEED! (.... and a little glide here and there)

The V loves the highway but it doesn't like anything over 65 mph. At 60 mph, the V will yield mpgs in high 50's. But, you have to leave your ego at home. You have to disregard the need for speed and the desire to run with the pack. Move over to the right lane set the CC to 60 mph and chill as everyone zooms by in a hurry. For my 33 mi. commute (one way), the difference between 65and 60 mph is 3 extra minutes.

It's entirely up to what you are comfortable with. But as I said above, you should be able to easily 40-42 mpg driving 65-70.

Today I did some testing on the freeway (I-5) doing 5-6 mile runs in both directions at different speeds. The temperature was around 39*F with dry roads and no wind. This part of I-5 is level as it gets (no FL level but good enough).

I ran it at 55 mph (kind of scary when traffic is zooming by at 60-70 mph), 60, and 65. Traffic started to get too heavy to maintain a constant speed above 60. Will try again at another time 70, 75, and 80 mph.

Once I get all the information together, I will try to post it and possibly plot it on some fancy graph like Bob Wilson's. Maybe Bob can chime in and give some parameters to keep this as scientific as possible.

Sometime, I will put together a video so you can see the V pushing 59 mpg at 60 mph on CC.

Stay tuned.

PS. My car has 14K on it but it has been churning over 50 mpg for the last 10k miles (on dry roads -- 42-48 when it's raining)?

 

I think this is a pretty serious point you bring up. It's not an ego issue, it's highway safety. Driving 55 or 60 on a road where most drivers are going over 70, and more than half are going over 75, poses a significant risk to others on the road. It's one thing if you're a huge truck and easily visible from a distance, and people expect you to be slow. But the Prius is pretty inconspicuous on the road.

For example, you may force an 18-wheeler or dump truck that should be in the right lane to merge left to pass you, which causes a ripple effect behind you, forcing the faster drivers to either merge left or slow down suddenly if they are blocked. This causes cars behind them to slow down, and so on. You may think "too bad, so sad" for them, but you're essentially causing a domino effect further behind you.
Not only that, you run a higher risk being rear-ended by someone not paying attention (going back to my point of inconspicuousness...)

However, all that being said (and off on a tangent, I apologize), I agree with you that speed makes a huge difference in MPG. Especially in the Prius v, because it is a lot less aerodynamic than the Gen III Prius. The drag coefficient is 0.29 (like the Camry), while the Gen III Prius is 0.25 (the Tesla S is 0.24, for comparison).

In a perfect world, my commute would be driving 45-50mph through a rural, hilly farmland with no traffic. Sadly, I think these kinds of commutes (and places) are disappearing.

 

Soylent,

I agree. After a bit of research, you drive on one of the worst highways in the country. I think we tend to assume (and I have been guilty of that) that drivers everywhere drive the same as where you live. In reality, every city or town has it's own traffic challenges and it's own driver challenges. So, your point is well taken. Don't be THAT idiot in who drives 100 or drives 60 when everyone else is driving 80 even if the speed limit is 55.

Here's an interesting article about I-95:

Report: I-95 through Florida is nation's deadliest highway &raquo; TCPalm.com

I'm sure there are similar articles about SoCal freeways.

Interestingly, I pay more for insurance for a car I have in Orlando (2005 Dodge Neon) than I pay for three cars in Washington. How screwed up is that?!!!

 

I wasn't aware that Florida highways were actually rated so badly. I always assumed it was like this everywhere (and I used to live near DC and the beltway is much worse in my opinion).

And I did forget to make a point that, obviously, going faster than everyone else is just as bad as going slower than everyone else. Put those two extremes together, and you have Florida highways. People driving 50 and people driving 85 on the same road, either ignorance or disregard of the slow/fast lane rules...
One does get used to it, though. You have to, if you don't want to drive in constant fear.

The downside is if I go out of state, everyone probably thinks I either drive like a jerk or I'm just crazy.

It's both

 

Important info regarding mpg's........WINDS....headwinds, vs. tailwinds, vs. no wind makes a big difference in mpg's.