How are you making so many MPGs!?!

[JimboPalmer]

Originally Posted by nullxposur

Why do you suggest fast take offs? If the engine requires the most energy to go from 0 to pickup, wouldn't it be a big loss of energy?

Time spent cruising = good gas mileage
Time spent accelerating = bad gas mileage

To maximize cruising time and minimize acceleration time, you need to accelerate briskly and get it over with.

[HTMLSpinnr]

Null, are you letting off the accelerator well ahead of when you need to stop or staying on and relying on the brakes at the end? Drivers who stay on (and consume) gas up to the last possible minute don't have a chance of getting great mileage.

[DeadPhish]

Originally Posted by nullxposur

Whoever posted that chart, it was really interesting when I saw it at the original post. It did make me think about driving the speed limit, but my switch to a hybrid is to limit changing my driving habits to that extreme. I had missed the disappointing MPGs threat. Very interesting!

As for taking off fast, I noticed the harder I was driving it, the more MPGs I was doing as opposed to when I'd use it on ECO mode. Why do you suggest fast take offs? If the engine requires the most energy to go from 0 to pickup, wouldn't it be a big loss of energy? I understand reducing the time you're stopped though.

In 'quick' start ups a good amount of energy is used in burning fuel but a good amount of that energy is stored in the battery pack. When you then get 'up to speed' and let off the pedal and coast you are using little or no energy at all.

OTOH if you try to crawl away from a dead stop you are depleting the battery at first until you reach the point when the ICE kicks in then it has to take over to continue to get you 'up to speed' and it has to replenish the depleted battery. Doing it this way uses more energy.

As to being at a stop it's not so much how long you come to a rest...it's having to come to a rest, period. That's the problem. As Ken noted above the best results will come on trips where you never have to stop...ever. It's the stopping that causes the problems. It doesn't really matter if it's for a second or a minute.

Newton's First Law of Motion

[a priori]

Originally Posted by HTMLSpinnr

Null, are you letting off the accelerator well ahead of when you need to stop or staying on and relying on the brakes at the end? Drivers who stay on (and consume) gas up to the last possible minute don't have a chance of getting great mileage.

+1. I think this is a bigger issue than learning to glide (or at least talking about it this way helps more!). Looking ahead and timing are huge issues in saving gasoline. Next: Correct tire pressure (meaning as much as you can take, though not to exceed the posted maximum cold pressure rating).

[wfolta]

My simplified summary:

* Accelerate at least fast enough to put the HSI display bar to the far right of the ECO area, perhaps peeking a bit into the PWR area. That is, accelerate briskly, but not like you're trying to beat the guy next to you so you can get in front of him.

* Look for opportunities to glide. That is, when you can let off of the gas completely -- until you see the instantaneous MPG hit 100 -- then gently press the accelerator until you have no bar showing: no regen, no ECO.

* Look at road conditions ahead and be smart about gliding, coasting, braking, and maintaining your speed. Consider cars behind you.

* Keep the car in ECO mode, and the A/C at 78 (which feels much. much cooler than 78 degrees in your house).

* Inflate front tires to 40 and rear to 38.

Following these guidelines (in the summer), I get 50+ MPG in our 2010 Prius III without trying any advanced hypermiling techniques or timing stop lights, etc. I have a mixture of city and interstate (with a mixture of open road, where I go 55-70, and stop-n-go backups) and my commute is about 12 miles each way. The car's breaking in (about 750 miles now) and I'm up to 55 MPG on this tank so far.

[DaveinOlyWA]

well, i dont think fast accelerating is a benefit. so you basically want to accelerate fast enough to not be in EV mode, but slow enough that you do not hit power mode on HSI. at least that is what i did to get my last 60+ mpg tank. i usually go up to 25-30 mph at just under the power band, then ease off until i hit the target speed which is either 40 mph. i will accelerate at that rate until around 40 mph if on a 50 mph road.

[Rybold]

Originally Posted by patsparks

For me it isn't about accelerating slowly, it's about lifting my foot off the accelerator when I know I'm coming to a red light. Avoid the brakes.
Read the MPG threads on PC for more information.

Indeed. I've noticed other Americans driving around me are also timing the stoplights a lot more again (like they used to when gas was $4.50). Maybe it's also just because people are "taking it easy" during the Fourth of July weekend. But, when I can, I try to not have to come to a complete stop. Sometimes, a stoplight is long and you have no option, but when you can, slow ahead of time and often that light will turn green and you are still going 10mph+.
(think of it this way: if you don't stop, you won't have to accelerate from zero, which in turn saves HUGE amounts of fuel)

Nullxposur, pretend brake pads are extremely expensive and you are trying to save your brake pads - the more gentle you are with them, the longer they will last. Hard braking "devours" your brake pads. It's okay to use your brakes and "be on the brakes," as long as it is gentle braking. Think of it this way, mentally, and you will see your mpg increase significantly. (what's actually happening here? it will cause you to lift off the gas and begin to brake sooner when you see a red light. and sometimes, that red light will turn green before you get to it. )

[wfolta]

Originally Posted by DaveinOlyWA

well, i dont think fast accelerating is a benefit. so you basically want to accelerate fast enough to not be in EV mode, but slow enough that you do not hit power mode on HSI. at least that is what i did to get my last 60+ mpg tank. i usually go up to 25-30 mph at just under the power band, then ease off until i hit the target speed which is either 40 mph. i will accelerate at that rate until around 40 mph if on a 50 mph road.

I think we're saying the same thing, though I allowed that you could peek into the PWR band a bit if traffic called for it. (I am very conscious of not being a jerk to those behind me. I won't trash my mileage because of a guy behind me in a sports car, but I do try to keep up, basically, with the flow.) If you take it to the right side of the ECO area (i.e. just below the PWR area), you'll accelerate fairly briskly, and at the same time get better mileage than if you naively try to accelerate as slowly as possible.

The naive assumption comes from some hypermiling guides and also from how you might understand the HSI and instantaneous MPG gauges. And also from not fully appreciating what a full hybrid does for you.

I think the original poster got MPG in the low 40's, so accelerating fast-but-not-furious, etc would probably pull him up to the low 50's without any tricks or inconvenience.

[nullxposur]

That's interesting because I'd notice that going "fast" was giving me more MPGs on the digital display than when I was on ECO mode and taking off and driving slowly. So, it seems it's mainly on coasting, maintaining a steady speed and avoiding revving the engine to pass, and using the brakes the least possible as a light form of hypermiling to make use of the most energy and avoid the vast energy needed to take off from a dead stop.

Thanks folks. I'm sure I knew some of what you all said. I just didn't know tha'ts what you all were doing. I read over the original window sticker and it said city averages between 42 and 52 (or close to that), so I'm at least in the minimum. This next tank gas, we'll see about that! ;-)

[patsparks]

Please keep us informed.