Could 'Pulse and Neutral' be the new 'Pulse & Glide'?

Which is EXACTLY why I think that most of this monkey business of trying to stretch the last few drops out of your fuel usage is really A BAD THING. We have enough distractions already; don't need more.

And yes, the engine will run more when the A/C is in use; in some circumstances, a LOT more.

 

I agree with you. If you are unable to to P&G then don't. Safety first.

I think you have a skewed view of this. There is a time and a place for the hypermiling techniques. IMHO they are not to be used all the time and not even most of the time. In all situations safety is always first. At the same time, if you can significantly improve your fuel economy why wouldn't you. Some drivers are able to use these techniques and some are not. As you said these are a "colossal pain in the nice person". I would say to you, don't use them. I say to others, use them if you are able and they make sense to you.

BTW, I don't see anyone here in this thread advocating getting the "last few drops out of your fuel". IMHO that would be very extreme to do on a daily basis. What I do see is people trying to getting better fuel ecomony. Doesn't that make sense to you.

I hope that we can agree to disagree on this without becoming adversarial. Have a nice day my friend.

 

No. For me, the end does not justify the means.
And sure EVERYBODY has a skewed view of EVERYTHING......in one way or another.

And I suspect that SHOULD be the case for most anybody who has to come to a place like this and ask a LOT of questions.......to be sure that they are doing it EXACTLY right. I think it's a "lemming" kind of thing.

But no hard feelings toward anybody who really discusses the issue and doesn't descend into "shooting the messenger".

 

One good thing about hypermiling....it prevents me from talking or texting on the cell phone at the same time. I see my close friends multitasking like crazy from behind the wheel with their smart phones and I cannot believe I used to do that.

 

It is a game. It requires skill, experience and more than a little knowledge about the car to maximize mpg. Like all games, if you don't want to play then don't. I think the lemming comment was unnecessary.

 

Maybe. But do you think it is not true ??

I think a lot of stuff these days happens just because people feel a need to "keep up with the crowd".

 

What other folks do is their business. I admit I do not always understand why they do the things they do. I shrug my shoulders and shake my head a lot, especially in todays political climate. I hypermile because I am a retired engineer, I drive a cool, high tech car, and it is a fun game. I do not know my lifetime mpg and do not care. I try to maximize each tank's mpg. Do that and the rest will take care of itself. I do not care if the "real" mpg is a bit less than what the car is telling me. Even after nine years I still see it as a challenge.

 

When they are piloting a deadly weapon down the road and a mistake can KILL other people, it then becomes my (our) business too.

 

i agree don't do anything unsafe. If you can't do anything safely don't do it

Hmmm... speeding, texting will driving, talking on cell phones, eating, ...etc...those are really unsafe. Concentrating on driving, awareness of your surroundings, not unsafe at all.

 

This is how I see it too. I can't try to maximize FE while talking on the phone. Or texting and googling stuff. Or eating. Most importantly, I have learned to give myself plenty of time to spare, because I've found that being in a hurry kills fuel economy. My punctuality has improved since focusing on fuel economy. It's nice not having to begin a conversation with the words, "sorry I'm late..."

 

Offtopic here, sorry. How did you get this on the display?

 

My opinion for what it's worth

I do not believe pulse and glide is as efficient a fuel saving technique as driving at a steady speed at the average of the pulse and glide speed. The reason is that air resistance is a significant drag on fuel mileage even at relatively low speed, 30 miles an hour or less. Air resistance is also proportional to the square of the speed of the vehicle. So a car traveling 30 miles an hour has 2.25 times the air resistance of a car traveling 20 miles an hour been though it's only covering distance 1.5 times as quickly.
Driving at a steady low speed allows the engine to turn on and off, just as pulse and glide does. So where does the benefit of pulse and glide come from?
In addition, no matter how you look at it, it requires a certain amount of energy to get from point A to point B. That energy is really the sum of all of the resistances encountered on the trip. A perfect car with frictionless bearings, no rolling resistance in the tires, an no air resistance with regenerative braking would never burn any fuel since Ebert stop would recover the total energy of every start and rolling at a steady speed would require no energy on average since you would recover the energy used going up each hill when you went down the other side. So the key to maximizing mileage is minimizing resistance to motion which includes engine friction, tire rolling resistance, air resistance, etc. Even driving on wet pavement decreases mileage because energy gets used to squeeze the water out from under the tires.


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The primary benefit from P&G comes from either increasing the amount of time the ICE isn't spinning at all, or (much more applicable to non-hybrids) from letting it idle when steady-speed operation would put the ICE in a very-non-ideal operating condition on its BSFC (brake specific fuel consumption) chart.

With many old non-hybrids not geared for efficiency, the idle fuel consumption rate was actually less than the power wastage of non-optimized gearing at common steady cruise speeds. Most newer non-hybrids have better gearing, narrowing the conditions where N-ICE-On P&G is beneficial. Prius has gone a long way towards getting rid of that benefit (when ICE is spinning) altogether.

 

True. Still: there are so many opportunities to pulse and glide, due to a slowdown in traffic ahead. Especially if you follow the car in front at a generous distance, you can very often "eat" that buffer, avoid the use of brakes, coast up to them. Then another pulse if/when traffic gets moving.

 

This is not a technique that requires belief. It may not be intuitive, but it works. If you have a ScanGauge, you can easily check that your mileage increases using pulse and glide as compared to steady speed driving. While your analysis of air resistance is correct, and at higher speeds it is a major factor in lowering mileage, at 30mph it is negligible.

 

Where can I find an advanced guide to efficient driving? As in, how exactly to p and g, etc

 

Sounds like you had headwind one way and tailwind the other. On my commute, I almost always get better fuel efficiency on the way back because the wind usually blows in the same direction.

 

Was the car warmed up at both ends? I'm always saddened to see the super-great mileage I can get if I start measuring a few miles into a trip. (Saddened because of how much the initial mile or so really drags things down. In my case, the car's garaged underground so it doesn't get too hot or cold while sitting there, but that is two floors it has to climb at the start of any trip. And, of course almost 0.2 miles of absolute coasting at the end of a trip.