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I have a Prius on order (yes, I decided to get one – it’s my equivalent of buying a luxury car). I want to ask about peoples’ experience with strategies for the best gas mileage on the highway (50-65 mph – obviously mileage decreases with speed). I’ve found 2 or 3 conflicting strategies on the Internets.

(1) A variant of pulse-and-glide, from John’s Prius user guide, available at: http://john1701a.com

“A beneficial technique for cruising is to feather the accelerator pedal at particular times... To do it, just lightly reduce pressure on the accelerator-pedal whenever you encounter a section of road that’s perfectly flat or has a slight decline. The MPG indicator will sometimes jump all the way to the +100 mark, even though your speed ends up dropping only 1 MPH. Then lightly push the accelerator-pedal to efficiently regain that speed afterward...”

(2) Keep zero flow in and out of the battery, recommended by efusco at Priuschat: http://priuschat.com/forums/kb.php?mode=article&k=23

“Once I get over the 25-30mph mark I begin trying to 'Dead-band'--on the energy screen all power is from Engine (ICE) to wheels with no arrows to or from the battery. This is the most efficient power phase as there are no losses from converting the energy to potential energy in the battery back to kinetic energy for the wheels.”

It is not clear how to actually do this, but my guess is through the next alternative:

(3) Just drive it steady – possibly with cruise control – and let the car worry about maximum efficiency.

Does anyone have experience about which is better?

There are reasonable arguments for each side. For pulse-and-glide: based on John’s Prius Info Sheet and Full Operation Guide, the engine revs at maximum efficiency and charges the battery during light acceleration (Pulse) and then uses the generated power during Glide. But there is always a loss of energy in charging and using the battery. By contrast, “just drive it” on the highway probably means that the battery stays charged and the engine drives the car. No in-and-out of battery loss, but the engine may not be running at its most efficient speed. (Any idea which is correct?)

I’m interested in any comments about Why it works – what makes for max efficiency – as well as How.
 

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avogadro said:
... but the engine may not be running at its most efficient speed.
Just a quick comment: In my opinion, the continuously-variable transmission (CVT) takes care of the efficient-speed problem all by itself. The engine can always run at the most efficient speed, as judged by the hybrid system.
 

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avogadro said:
Does anyone have experience about which is better?
Welcome to Prius world!

At the beginning, please be aware that Prius is a completely different animal between below 42 mph and above 42 mph.
Above 42 mph, the ICE is always spinning and (1) and (2) technique you mentioned do not work well. Only (3) drive it steady works above 42 mph.

Good article about Pulse and Glide is found at...
http://hybridcars.about.com/od/ownershi ... dglide.htm

[email protected]
 

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When I'm on the highway (speed >= 55) I use cruise control or when there's lots of others on the road, I stay with the flow of traffic. I just don't think it is safe to be slowing down and speeding up all the time.

My life is more important than a few gallons of gas.
 

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One thing that should be mentioned regarding highway mileage:

If you want to maximize your MPG - SLOW DOWN!!!

I've found the difference between 65 MPH and 75 MPH can be as much as a 10% increase in fuel economy. I'm sure others agree.
 

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dgstan said:
One thing that should be mentioned regarding highway mileage:

If you want to maximize your MPG - SLOW DOWN!!!

I've found the difference between 65 MPH and 75 MPH can be as much as a 10% increase in fuel economy. I'm sure others agree.
I second that. I drive almost 200 per day, and almost all of it highway. Traffic makes any attempt to glide impossible in any meaningful way. It can be done a little (turn off cruise control on downhill runs, etc.), but the variability in speed will find you with a semi up your rear bumper. I find that using cruise control keeps me from accidentally going to fast on gentle downgrades (you can wind up going over 80mph without realizing it if you keep your foot on the accelerator when you don't need to -- the engine is that smooth).

Unless you are going on unusually hilly terrain, my vote is for cruise control as often as possible. Let the computer do the work.
 

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RE: Highway mileage strategies

The trip from my house to work is pretty much a 15 mile drive up a highway that is easily 85% overpasses. So I am nearly constantly going up and down.

(Keep in mind I've only had my '06 for 77 days now) :D

When I would just put it on cruise control, at the speed limit +1, the screen would tell me my average was around 47 mpg. And I found that when I filled up the calculation showed it wasn't far off...

I decided to try something different...I would accellerate to 70MPH (5 over the posted limit) and then hold the pedal at the same position the whole drive, letting the car slow down to ~65 on the way up the bridges and speed back up to 70 on the way down. Every now and then I would end up getting below the posted limit and have other drivers flying around me (heck, that happens when you only go the limit anyway!) Basically I was try my dardest to keep the current MPG estimate at 50+.

According to the screen, my average was up to 48 or 49 when doing this. My last to fillups, however, have not shown this to be true. While I ended up with an overall average of ~47, according to the screen, I was calculating my actual average to be closer to 44!!

Siince I filled up today and I'm planning to go back to the cruise control method and see if my actual goes back to something better...We'll see.
 

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For freeway driving, I set my CC to 58 MPH and drive in the right lane. This has taken my average from the mid to high 47 to the low 50s. This is based on the MFD and not actual mileage.

Another thing that can help is to follow a large truck. Not too closely as that is dangerouse. But I've followed trucks with about 3 car lengths between it and me and can see the differance. I followed a gas tanker for 15 minutes and my MFD showed ~75 MPG over that 15 minute period.

Again, I want to stress that this can be dangrous if you follow too close. I've see these big trucks run over things on the road causing them to bounce up. Follow too close these things can fly through the windshield.
 

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Whereas I try several techniques to achieve max. mileage below 42 MPH, on the highway, unless I'm traveling out of state (once-twice/year), I go 62-63 MPH. And I always use cruise control. If I encounter a hill to ascend on the highway, I tap down the CC 3 times (if no one is close to my rear). If downhill, I might flip it in neutral and coast up to 80 MPH as long as it's clear sailing.

Request to Redblue88: would it be possible to move your avatar (which is sized incorrectly for an avatar) to the signature area like all the others? It messes up the screen. Thanks for listening!
 

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highway driving

I have made many road trips with my 04' prius and have found that cruise control works best. At 60 mph you will get best mileage. I however set it at 65-70mph usually depending on traffic and lanes and I have been getting around 50mpg for these long trips (6-8 hours).
 

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I picked up our used '04 in Washington DC two months ago, set the cruise at 60 and drove home to SE PA. I was thrilled with 63 average for that 120 mile trip. 7 tanks later our oveall average is 55, but I've never been able to get that 63 over a longer distance. I'm wondering if I didn't have a bit of a tail wind that day. I also noticed the following day that the former owner had the tires at 28 psi! I now have them 44/42. All that to say, yes I think cruise is best on the highway, bumping up and down one or two mph as I go up and down hills, and set at 55 or 60 if possible depending on traffic.

PA P
 

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here's my ideas

1 Drafting. yes in highway driving getting close to big rigs or other SUV's will shoot up the mpg to about 70 mpg. Being alone in traffic and the mpg drops.

2 keeping your momentum. What this means is that when you approach a green light and you see cars stopped for their red light, let off the gas and coast to the light. hopefully the light will change to red and you stop. if not, you still got momentum to pass the stopped vehicles. I like to think of it this way... If i want to start moving a train, you got to have alot of energy to move it. if it's already in motion, keep it going until you need to slow.

3 if it's a road with no cars and the speed limit is 55, i'll go 40 and use the electric instead of gas.

4 going 40 mph.. use the electric as much as possible

5 going downhill, go into "virtual" neutral (car in drive, engine is off, no power going anywhere)

6 limit use of braking. Since the Prius has regenerative braking, this will slow the car down. then take a turn that will not kill your momentum if possible.

7 This one's tough, but would help, getting the battery power in the energy menu in the green. this will let you use the electric more than the gas. I heard that if the battery gets all full of green bars, that's bad for the battery.

I can't think of anything else. This is my 1st time here and I love my prius.
 
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