Still confused about Pulse & Glide

[Aaron]

Yes, I've done a search on P&G, but I'm still feeling a little confused.

I have a 2008 with 1,200 miles on it and I'm averaging about 47 MPG right now. Not too shabby, but I've been reading of 80-100+ MPG so....

I would like to see more MPG (of course) in my daily commute to work, but I'm unsure if I'm applying the correct P&G method.

How should I drive my Prius when my distance to work is 18 miles one way and my average speed is about 50-60 MPH on a country road?

From what I gather I should "stomp on the gas until I reach around 40 MPH....let off and and SLOWLY tap the gas until I reach the desired speed b/t 50-60 MPH...then GLIDE slowing down back to 40 MPH again?" Did I get that right? Wouldn't that make the guy behind me angry?

Here is what I was reading:

"You want to accelerate up to a maximum of 40 mph in the “Pulse” phase, begin the “Glide” phase and coast down to a lower target speed. Once the lower target has been reached, you want to re-initiate the “Pulse” phase, re-accelerate back up to a maximum of 40 mph and repeat when and where applicable."

How do I apply this to my daily commute as I described above?

[efusco]

Concepts you're missing:
1) True gliding is only possible at speeds below 41mph.
2) If you want to try P&G above 40mph you have to learn to hyperstealth glide....a no arrows (or yellow arrow from battery to wheels only) condition on the ENERGY display, but underneath the ICE is actually spinning. This is MUCH harder to achieve than a true (sub-40mph) glide.
3) There is no "stomping". It's a moderate acceleration up to your target speed. If you're any good at engine sounds you, ideally, want b/w 1700-2300rpm. This is constant for any part of your range of speeds.
4) Finally, if it's a country road you should consider going slower if at all possible. If you can keep your speed to a max. of 50 rather than 60 your mpg numbers will climb dramatically.

So, if I were you I would do moderate acceleration up to ~49-50mph let my foot off the pedal than very gently ease the pressure back on while letting speed drop off and searching for that hyperstealth glide. Let the speed drop as far as you can tolerate...if you can't tolerate to the 30s range then do not let it drop below 42 or you risk the ICE shutting down then having to restart again (energy waste) as you go back into the next pulse to your top speed (50).

Clearer?

[bwilson4web]

You might consider another approach, if the route permits:

• 1-2 miles - speed about 25-30 mph while the vehicle warms up
• 14 miles - set the cruise control and enjoy the ride, speed of no more than 65 mph
• 1-2 miles - speed about 30 mph while the vehicle uses the stored energy to cruise into work

The advantage is you are just managing the warm-up, letting the hybrid do the cruise and on cool-down, reaping the stored energy.

GOOD LUCK!
Bob Wilson

[nerfer]

Originally Posted by Aaron

Yes, I've done a search on P&G, but I'm still feeling a little confused.
:
How should I drive my Prius when my distance to work is 18 miles one way and my average speed is about 50-60 MPH on a country road?

From what I gather I should "stomp on the gas until I reach around 40 MPH....let off and and SLOWLY tap the gas until I reach the desired speed b/t 50-60 MPH...then GLIDE slowing down back to 40 MPH again?" Did I get that right? Wouldn't that make the guy behind me angry?

First a couple definitions, using the energy screen:
Pulse = acceleration with arrows from engine to wheels, no battery assist
Glide = no engine, no batteries, no arrows anywhere
Coast = engine is on, no batteries, may show 99 mpg

So Pulse does NOT mean you "stomp on the gas". It's an accelaration, not slow but not hard. Glides generally only work at speeds under 40 mph. Above 41 mph the engine needs to be turning so the electric motor doesn't overspin, so at your speeds, you'll be mostly coasting, not gliding.

"Pulse and coast" may work for you. True P&G, which never goes above 40 mph, would definitely get people behind you upset. But in either case, this is not the difference between your 47 mpg and 80-100 mpg. At your speeds, some people have shown that cruise control will do as well or better than pulse-and-coast (depending on traffic and other conditions).

The 80 mpg+ numbers are generally done in special test cases, not real-world commutes (except for Wayne Gerdes, who does get people upset sometimes). But many people (although still a distinct minority) do get over 60 mpg in everyday commutes. Generally they start with putting higher pressures in their tires (>40 psi) and watching traffic, starting to coast before the areas they know they'll need to slow down in. (Generally you want to avoid using the battery). Then they block the grill and add engine-block-heaters for cold weather, hook up a ScanGauge, add EV button, etc.

With your commute you should be seeing mileages at least in the low 50's in anything above 40'F. Practice accelerating with only arrows from the engine to the wheels when you can, slowing down in advance of using the brakes, and make sure your have tire pressure above the recommended minimum of 35/33. If that doesn't get you above 50 mpg, keep reading the fuel efficiency forum. Blocking the grill in cold weather will help, but it's not worth the effort this time of year.

(Not everybody should expect 50+ mpg. I based this on your longer commute, your medium speeds, and what I know of your local climate).

[xsmatt81]

when i accelrate i can rarely get the engine to just put power to the wheel,s the electric comes on and off all the time. I have been in glide, or super glide though..and its cool

[efusco]

Originally Posted by bwilson4web

You might consider another approach, if the route permits:

• 1-2 miles - speed about 25-30 mph while the vehicle warms up
• 14 miles - set the cruise control and enjoy the ride, speed of no more than 65 mph
• 1-2 miles - speed about 30 mph while the vehicle uses the stored energy to cruise into work

The advantage is you are just managing the warm-up, letting the hybrid do the cruise and on cool-down, reaping the stored energy.

GOOD LUCK!
Bob Wilson

If the middle 14 miles is all highway with few stops I think this concept is just fine and is much as I would do given flat terrain with few or no stops. But I'd drop the speed to 50mph along the route as described.
I was specifically addressing the pulse & glide question, but certainly the advantages of Pulse & glide diminish at speeds over 40mph and it becomes more difficult to do as well.

I also agree that keeping acceleration very gentle and speeds slower at the front end is important while doing warm-up.

[morpheusx]

Originally Posted by efusco

If the middle 14 miles is all highway with few stops I think this concept is just fine and is much as I would do given flat terrain with few or no stops. But I'd drop the speed to 50mph along the route as described.
I was specifically addressing the pulse & glide question, but certainly the advantages of Pulse & glide diminish at speeds over 40mph and it becomes more difficult to do as well.

I also agree that keeping acceleration very gentle and speeds slower at the front end is important while doing warm-up.

Ironically this is a very similar route to my daily to and from work and this is almost exactly what I do (when possible) on my route to work. The highway speedlimit for my route through downtown Akron, OH varies from 45 - 55 so I just set the cruise at 50 the entire way. In decent weather conditions it is rare that I don't average 60 MPG and on occasion I'll have a good bump to 75 - 80 MPG due to a favorable tail wind. I would love to see what I would average if we didn't use my Prius as the "family" car.

[Rokeby]

Here is a little game I created to help me internalize the right go-pedal
movement to get no yellow arrows to or from the HV battery. It may help
others too.

I noticed that even under even, steady acceleration sometimes the yellow
arrows went into the battery. Then moments later, they switched to going
the other way. Nowhere had I read what I was supposed to do to get no
arrows. Many posts talked about the no-arrow state, but none I had read
told how to achieve it.

So, I fiddled with very small go-pedal inputs. I found that when the arrow
was pointing up, into the battery, more go-pedal made it go away. When the
arrow pointed down and to the left, out of the battery, letting up on the
go-pedal made it go away.

So what's the game? To make the needed correction I needed to react
instinctively, instantaneously, without thinking. So the game is the arrow is
a snake, let's say a king cobra. When the cobra rears up threateningly, you
step --very, very gently of course -- on its head and he disappears. If the
cobra is slinking away off to the left, you hasten his departure by easing up
on the go-pedal. Kind of childish, but it worked for me.

For me the game was just an intermediate stage. I soon learned to instantly
take the right go-pedal response for up or down arrows without consciously
dealing with the "snake."

One caution, sometimes the display goes into an indeterminate state for a
few seconds with the arrows, snakes, rapidly alternating up and down. Just
hold the go-pedal steady and in a few seconds it settles to up, down,
or none. Then react as appropriate.

[Tdoff1]

I know this topic has been beaten to death, but I am bear away I go..... I am getting better at the "glide", but still cannot get the hang of getting to speed efficiently. (only 1 week on the car). My daily cummute is about 30 miles, almost all highway. I am getting 45+MPG NOT using the cruise and feathering the gas on my own. works great when traffic is moving, but stop and go is a pain. I assume that using the cruise control is not as efficient as manual.

I welcome any info. First tank of gas averaged 46MPG, hope to get better.

Cheers

[Danny Hamilton]

Originally Posted by Tdoff1

. . . .I am getting better at the "glide", but still cannot get the hang of getting to speed efficiently. . . .cummute is about 30 miles, almost all highway. . . .

If by highway you mean expressway at speeds above 45 MPH, then "glide" is not possible at all, and you probably want to investigate other meathods such as SHM (Super Highway Mode?)

Originally Posted by Tdoff1

. . . . I assume that using the cruise control is not as efficient as manual. . . .

That really depends on how much effort you want to put into learning and putting into preactice the various manual control techniques that have been found to help. I've found that this time of year without a headwind and no rain, if I use cruise control set at a reasonable speed I am getting better than 55 MPG on a regular basis.

When I attempt manual control of the accelerator I frequently end up with between 50 and 55 MPG, though occasionally I "get it right" and manage a bit over 60 MPG.