MPG Help First Post New Member

I'm averaging 50 plus or minus going to and from work, though the morning is less, the afternoon more, and will finally have to fill up my tank next week for the first time.

But interestingly I just for the heck of it set the trip meter halfway home yesterday. Final six miles were 3 freeway at 50 - 65, then streets with three stoplights, then a mile or so of back streets and three or four stop signs. The trip meter had 72 mpg final avg for that short trip. I'm in almost full electric going down the side streets to the house. Seems the freeway really charges up the battery?

Going back down to deep winter here so mileage will surely suffer. (may even freeze!)

Makes me like the car even more!

 

Wow I clearly need some lessons. I am averaging on the current tank (so far about 90 miles) 38.9 mpg. I inflated my tires yesterday to 41/40. I almost never use the heat (unless it's very cold). My commute is short stop 'n go side street travel of 6 mi each way, so not much I can do about that. Best I've ever gotten is 39.9 mpg. Odometer reads 470 miles. The car came to me with 169 miles on it.

 

I'm always surprised in these mpg discussions not to see more people complain that terrain ruins mpg. We got our Prius on Dec 29 and have put almost 2500 miles on it. Our best run for mpg was from Waco, TX to Austin, TX, where we finished the trip at 55.2 mpg. Worst trip from Longview, TX to Dallas and back - we got 43.3 for that tankful -- attribute that to several short stop-go trips and the long trip was in heavy rain running the defrost. Back home in rural East TX we struggle to top 48 mpg for a whole tank. Seems the mpg avg tops 50, then we come to a hill and take a serious hit; these rolling hills just butcher our FE. Our most common commute is about 25 miles one way. I set the cruise to 65mph and counted the number of times we went into the pwr region - 15 times in 25 miles. If I set the cruise to 60mph we can hit 48-50 mpg, and if I forget the cruise and keep in eco range we can get 52-55. The hills kill us.

 

Your short commute is the biggest killer because of warm-up.

So the first thing is to try and shorten warm-up time, which means do some grille blocking. Ken@Japan has what seems a safe grille blocking strategy:
http://priuschat.com/forums/gen-iii...prius-grill-blocking-strategy.html#post862373

Then since you're driving in warm-up a lot in winter, you want to avoid working it hard. If the car were warmed up I be suggesting to try all the normal stop-and-go techiques: use a slower steady speed instead of stop-and-go where possible; time any lights; glide or use moderate braking to stop. However, I'm not sure myself how best to drive in stop-and-go during warm-up, so I simply try to take it easy.

 

I think people mention it less because terrain ruins mpg in all cars*. In hilly areas DWL (Driving With Load) is your friend, as you have found.

(*Although, I believe that Ken@Japan wrote that short 6% inclines followed by 2% declines are great for mileage as it effectively gives you pulse and glide.)

 

This seems to depend on conditions. There are many hilly areas that don't bother either this Prius or my older non-hybrid, also tracked by a ScanGauge, if consumption is counted over a round trip, at least back to the same elevation.

Climbing does consume more fuel. My rule of thumb is to allow an extra gallon per 10,000 feet of climb with the Prius. Yours should be within +/-20% of that, and it will vary with cargo load.

But descents seem to make up for that if the slope is shallow enough to not require any significant amount of engine braking or friction braking. Serious regen braking that doesn't fill the battery should have some fuel cost -- better than braking but worse that coasting -- but I haven't had enough of hills in that range to characterize it.

Those 7 mile 7% descents are mpg killers. While instant mpg is infinite, the car doesn't get much distance for the gravitational potential consumed.

The non-hybrid doesn't easily fit into a similar rule, but rolling hills make for a natural terrain-following pulse and glide pattern, again recovering the climbing fuel if the descent is not too steep.

 

I've mentioned the terrain as a factor in my mpgs. Lots of long, low hills--just enough to force the car into needing that PWR mode to keep up with the flow of traffic.