Pulse / Glide

I have found that if I keep my cruise control between 50 and 55mph on the freeway, on longer trips I'll get 55-65mpg. The drive between Seattle and Tacoma comes to mind - about 90 miles round trip for me. On that run, I typically get 63mpg with cruise control alone. I'll also get flicked off and cursed at a number of times...

Staying under 38 alone isn't enough to maximize fuel economy on shorter trips. In my experience, moderating acceleration, using hills, pulse/glide, etc, are all keys to the short haul. Driving the Prius like I'd drive a conventional car, I'll get 45 around town. Driving it more like a Prius, I'll get closer to 50.

 

I stayed below 40 as much as possible last month and finished off a tank this past Saturday that I started on 7/6/08. It lasted 1143.0 miles and it averaged 92.2 mpg.

 

Show-off

I don't know how you guys get that good MPG and so many miles.. I can almost hit 60MPG..Congratulations

 

The MFD is usually optimistic and I found that the odometer under-reports by 1.6%.

 

First of all - WIPE THAT SCREEN OFF!

Secondly, quit showing off.

... Brad

 

If you're going to have a 60 MPG tank, then you're doing something right, and congrats.
But some of the the things you say could be mis-understood by a new Prius driver.
First, the P&G technique can be applied at any speed, for any combination of duration and it's not boring, aggrivating nor dangerous if done sensible.
P&G is really a method to get the Prius gas engine (ICE) to shut down and stay shut down, for as long as possible. Knowing how to do it is important, and when to do it even more so.
And the sooner owners realize their car is capable of moving, and using no gas, the better they will try to maximize the time it spends doing just that.
Second, the word "coast" just can't be used with the Prius to communicate anything. Coasting in a regular car simply means taking ones foot off the gas, and it's the only other alternative to having ones foot on the gas.
In a Prius there are several forms of "coasting". And all of them are ways of traveling with no gas consumption.

Those forms of "coasting" I speak of are Regen, Glide, and Stealth.
Simply taking you foot off the gas allow the ICE to shut down and starts Regen (which is good), but unles you need to slow or stop it's drag is inefficient.
Having taken your foot off the accelerator and then then lightly reappling pressure on the accelerator,
you will start a glide (no arrows). This is really the highest form of travel efficientcy in Prius. Apply a little more pressure and electric power is initiated and that's a good, gas free, way to travel too, up to a point.

Third, the whole idea of staying below 42MPH, or driving "slow", is not to just poke along at slow speed, but rather, being below 42MPH allows full exploitation of the Glide and Stealth capabilitys, differently than can be done above 42.
A knowlegable Prius owner need to know what it can do, and when.

P&G is a Prius manipulation technique. Enertia management is simply efficient travel, in any craft. But they do go hand in hand.

A pulse is really anything that initates acceleration, and a glide (regen or stealth) any ICE off mode that maintains forward motion without the use of gas. Maximizing the latter is what the Prius is all about.

 

Well, here is a lad that get's it!!!!
I could not have said it better myself!!!

I used to go to the Reno Air Races for many years, and one of the attractions was a gentleman named R.A. "Bob" Hoover. He would to demo flights with a P-38 Lightning and another type of twin engine aircraft. The whole point of these flights was to demonstrate "Energy Management" as it applied to flight. He woulod get to a certain altitude and proceed to shut off the engines. He would then spend the next 20/30 minutes just gliding. building up speed in a dive, and using that speed to climb back to altitude, while doing twists & turns. I watched that routine many many times, after all we went 20 years in a row!!. He was VERY GOOD!!!

The day I got my Prius, on my first drive, all I could think about was Mr Hoover, the Energy Management Series, and applying those techniques to driving. No not climbing and diving, but the use of inertia, brakes, and accelerator!!! Now 3500 miles later, driving through the foothills of Los Angeles, my first tank was a pitiful 41MPG. But I learned to "Fly" the car, and its paying off!!! I am now getting 47+ MPG.

It has actually been a very enjoyable learning curve!!

73 de Pat KK6PD

 

Inertia or energy management is a nice way to describe it.

Summarizing: to maximize fuel economy
- Don't floor the gas pedal, but do accelerate briskly (the engine is most efficient under substantial load)
- Gliding (no arrows) is better than coasting,
- Coasting is better than braking,
- Braking is better than stopping.
- Don't use "B" (it's there only to avoid riding the brakes on long downgrades).

 

That is so far removed from any other stats I have seen quoted on these boards over the years, that I find it difficult to believe. Are you sure your numbers are correct, or are these simply terminological inexactitudes!

 

Do you think he doctored his pics?

As one with 76 MPG on the current tank, with 5 pips gone after a little less than 500 miles, I believe him. I do my driving mostly in urban and suburban areas with occasional hills, whereas his is mainly on lightly traveled flat rural roads. I am confident I could come close to replicating his results if I had his driving conditions.

 

As Jim said, see pics above.

 

Thanks 9G-Man! I've read abount this so many times I had sworn to wait til we have our Prius before reading about P&G again. But I just read your post. I have to be honest, I'm not sure if it's just starting to sink in, or it's your explanation, but I'm beginning to understand and it's starting to make sense. One of my handicaps is that I'm reluctant to try or keep doing something if I can't understand why or how it works. It's similar to the technique, re: OD, that I stumbled onto using my SGII on our Avalon that has resulted in a ~10% improvement in mpg. I doubt most people are aware of it and most probably don't understand it, so, few replies.

 

So that means that you consumed 1143/92.2 = 12.4 USG of fuel. But the Prius gas tank, by all accounts holds only 10.0 - 11.0 USG at best, despite being rated by the Owners manual at 11.9 USG.

How do you explain that?

 

This is the 4th time I have put over 12 gallons in my car. Here is the receipt from the pump when I filled it last.

How do you explain this?

The Prius will hold more than 10 gallons and will easily hold the full rated capacity. If you want to talk to our own FireEngineer(Wayne Mitchell), he will tell you that a Prius tank can be stuffed to ~13 gallons or more if done properly. I don't reccomend stuffing a tank but, I do know how to do it and have done it for the whole 22K+ miles I've had the car. Just because something isn't believed doesn't make it untrue.

 

oops.:redface: duplicate post.

 

So how do you stuff 13.0 gallons into a tank with a maximum rated capacity of 11.9 gallons? Do you remove the metal tank exterior and just expand the bladder container!? Or just remove the bladder? o

Seriously, the most I have put into my Prius tank is 11.12 USG; that after driving with a single bar blinking for around 5 miles. Not that I would advise doing that, but I wanted to make the Costco in Stockton where gas is usually cheapest.

I would certainly like to know how to you get more capacity without compromising the emissions controls.

 

You can get that much into a tank with that rated capacity the same way you can get more than rated capacity in just about any vehicle tank. There is room for expansion of the bladder inside the steel tank. This would not be possible during the winter when the temps would cause the bladder to contract. And, speaking of blinking pips, my pip was blinking for just over 150 miles this time. As for stuffing the tank without damaging the emissions controls, there is room for some expansion before damage would occur. Granted, on a Prius, there isn't as much as other cars. I believe that as long as you don't cram the tank full and go park it in the sun for the rest of the day without driving more than a mile or two that there won't be any damage done. As I already mentioned, I have over 22K miles with no codes/problems. I also live ~14 miles from the station I fill up at.

 

Pulse & Glide help?

Wow, that's nuts.

I average 53MPG on the highway, more with hills. This using the "lifting" technique: I gently accelerate to speed, then lift off the accel pedal a bit at speed for a boost in economy while maintaining speed.

I can't seem to get P&G right though on the highway. Every time I try, my average creeps down rather quickly. I don't have a ScanGauge or anything so I can't tell where the engine's most efficient RPM is without knowing what it's supposed to sound like.

Any pointers?