Proper way to accelerate?

on a one lane road, if you have someone behind you, it's only polite to keep up with the car in front of you.
if there's no one behind, accelerate just to the right of eco until reaching cruising speed.

 

Agree with Bisco - you do however want to get to cruising speed reasonably quickly; a slow acceleration that lasts a long time could end up using more fuel than a quicker burst that lets you then cruise and coast.

 

yes, you want to fire up the engine once you hit 10 mph or so. you don't want to go into the power area unless necessary. your graph is a little different than mine, i think you want to stay just into the eco area, above the line that separates it from the hybrid eco area.

 

no, see my edit above.

 

IMO...and it's just opinion, is don't overthink it.
The proper way to accelerate is whatever is safest.

Just like any vehicle, repeated aggressive jack-rabbit starts use up fuel.
Smoother, slower accelerations use less fuel.
But really? When I accelerate I want to be paying attention to my driving surroundings NOT where my Prius HSD graph might be at any given second.
Unless you are starting out every single stop and start by slamming your accelerator down, then my guess is any minutia of change isn't going to make too much difference. Accelerate based on what you need to be safe in traffic, not what you imagine is giving you the most economical results, from a graph on your dash.

The proper way to accelerate?
Safely, given your driving environment and surroundings.
.

 

Mash the throttle, get to speed and set cruise control, even at 25mph, the sooner the computer runs the computer, the better the mpgs, unless you follow.

 

We never use Eco mode, 99 percent Normal, and rarely Power mode.

Don't drive much different from a normal gasser, no jackrabbit starts. You can see our fuelly mpg average below in my signature.

 

+ 1 for post # 8.

In that regard, noting your desire to maximize fuel savings, utilize the "power bar" screen and just try to stay of the red zone (power).

 

+1 for post #2 "keep up with traffic", +2 for post #8 "drive safely" and +1 for Post #12

A couple of thoughts in support of keeping up with traffic:

Like many Prius drivers, I initially obsessed over the display & the challenge of maximizing fuel economy, reinforcing the reputation of the Prius and its owners as slow....

Regarding acceleration and fuel economy, my take is to encourage wider adoption of the Prius by dispelling the myth that it is an abysmally slow car. It can be driven like any normal car and easily keep up with traffic and is exceptionally fuel efficient by design.

As for technique, the prior comments cover it. The most important fuel economy technique is to anticipate traffic and stops - coast and use regenerative braking and you'll do less accelerating as a result. I don't find overall mileage to be much affected by acceleration so unless I have the road all to myself I just go with traffic which is usually right up to or slightly in the "PWR" power area (I'm not saying to stomp on the pedal). On hills, merges & fast traffic you'll go well into PWR. You're generally in the power zone (battery assist) briefly so don't obsess over it. As mentioned, keeping it in the "Hybrid Eco area" (battery only) for more than the very first part of acceleration is no fun, annoying to passengers and other drivers and actually less efficient, there are discussions of technical reasons if you want a deeper understanding.

It's so rewarding to drive the Prius, I like to show other drivers that it's not a slug and maybe get a few more people to consider getting one.

 

You're welcome - I haven't been in South Florida for a while, but fast off the line and jockeying for pole position at the next red light is common most places I've driven in the US. I'm not saying to join in the idiocy, just that pokey driving can be unsafe if it frustrates other drivers and that it reinforces the negative Prius stereotype.

I can expand a bit on acceleration if you're interested. The driving modes ECO, Normal, and PWR mainly alter the sensitivity of the accelerator pedal, so people use them in different ways, it's mostly personal preference. ECO also moderates the cooling and heating energy use.

To accelerate efficiently from a stop, just use the pedal smoothly but deliberately so you get up to several mph using battery. If you leave some space in front of you in line at a light you can get rolling without hanging anyone up. Then the gas engine will kick in quickly if you're accelerating anywhere near normal for the hyper drivers around you, anywhere from a bit above the midpoint of the HSI indicator to the PWR zone is very efficient. You don't want to keep accelerating on battery since using the gas engine once you're rolling is efficient (engine at optimal rpm's and no conversion losses). This is maybe the most counter-intuitive thing and the bonus is you have to use the engine to accelerate "normally" anyway. The further into the red PWR zone, the less efficient since you're using the battery to assist (conversion loss) and pushing the engine rpm's out of optimum efficiency band. But again, use whatever power you need, the engine is quite low power by itself and the PWR zone is likely needed in normal driving. To keep from hindering the drivers you're describing, you may often need to get a bit into the red. It won't much affect you're mileage & won't hurt the car.

Since you're already clued in on coasting and regen braking, you're really getting into diminishing returns. Do you have your tires pumped up a bit over the sticker recommendation? You'll see a lot of people here recommending 40 psi and even max sidewall pressure, I've settled on just 2 to 3 psi above the sticker, again diminishing returns and the ride gets a tad harsher with higher pressure.

 

Sounds like you've got it!

On tire pressure, if you're happy with 43/41 then you're good to go. I've read up on this and you're not going to get any notable mpg benefit from going higher and there are other tire performance aspects that could suffer.

On the A/C you're already doing the right things. The Prius has a variable speed compressor and ECO mode modulates that for efficiency as well as fan speed and air recirculation. I don't know the specific efficiency gains of ECO vs Normal and auto vs manual A/C, there are threads that go into more detail on A/C and ECO mode if you want to dig deeper. I use ECO mode almost exclusively since I like having finer control of the pedal and frequently use Automatic A/C. I think ECO mode limits the compressor speed when cooling and the amount the ICE runs just to supply heat, so basically it takes longer to get to your set temperature. I was shocked at how loud the compressor got it Normal drive mode when I first used the A/C on a hot day - I think I had temp set low since I had last used it to heat. I'm pretty Spartan with heating and cooling and like you set the temp high in hot weather and low in cold. In auto mode I just start at the lowest temp (65) when heating and bump it up as needed once the engine warms up. When cooling I start it high, say near 80 and bump it down a bit as the cabin cools off. One thing to keep in mind is the traction battery is cooled with interior air so you're helping that by not going crazy with how warm you can stand.

 

Having monitored hybrid battery temps for some time, I saw pretty much no drop with AC use. Even running on cool evenings, the battery will level out around 35C. It appears to be normal operating temp.

 

My experience is you get EPA MPG by just driving it without doing anything beyond ECO, Auto, anticipation and reasonable.

I use cruise control when on the uncrowded highway and might be 2-3 miles under the limit if no congestion and I'm in no hurry. If I'm in congestion, I'm anticipating, smartly off the line as the light changes, and up with traffic. Once away from the light and at the speed limit, I help people pass me.

I drove very carefully for the first few tanks being fanatic to keep the indicator below the line but then I concluded I was getting only maybe 5% better MPG but at what cost to my stress level? I'll take the 100% better than my previous cars and drive to relax.

My 30k miles have been a ~50/50 mix of city and interstate with generally hilly but not mountainous country.