Pulse & Glide *-*101

[rufaro]

I have had Bruce, the black shark stealthmobile since May 10. I have been trying to see how pNg works, but, given most of my driving is around (small) town w/ lotsa stop signs, I haven't had much scope for experimentation. I found about 1/4 mile street that I can sorta see whassup, BUT: would someone PLEASE take pity on me and explain, in words of 1 syllable or less, WHY NO arrows is better than GREEN arrows...?

[xxxlmpg]

<div class='quotetop'>QUOTE(Rufaro @ Jun 7 2006, 11:29 PM) [snapback]267712[/snapback]</div>

I have had Bruce, the black shark stealthmobile since May 10. I have been trying to see how pNg works, but, given most of my driving is around (small) town w/ lotsa stop signs, I haven't had much scope for experimentation. I found about 1/4 mile street that I can sorta see whassup, BUT: would someone PLEASE take pity on me and explain, in words of 1 syllable or less, WHY NO arrows is better than GREEN arrows...?
[/b]

Mo men tum

[windstrings]

<div class='quotetop'>QUOTE(Rufaro @ Jun 7 2006, 09:29 PM) [snapback]267712[/snapback]</div>

I have had Bruce, the black shark stealthmobile since May 10. I have been trying to see how pNg works, but, given most of my driving is around (small) town w/ lotsa stop signs, I haven't had much scope for experimentation. I found about 1/4 mile street that I can sorta see whassup, BUT: would someone PLEASE take pity on me and explain, in words of 1 syllable or less, WHY NO arrows is better than GREEN arrows...?
[/b]

Humm.... I think the idea is that there is no point in using Kinetic energy to make electric energy to burn as kinetic as its put to the wheels again.

The only reason you want energy going to the batteries at all is if your speed is out of control and you need to brake while going downhill or while the ICE is on to go up a hill.

Coasting is the most efficient way to go as far as you can go on a given amount of kinetic energy.
If you let off the brake enough for it to start regening the batteries, you will be slowing yourself down to charge and eating into your kinetic energy or "momentum".

the "pulse" part of the equation is when the ICE has to come on to get back up to speed... if you have used battery and its depleted, the ICE will really work hard to charge it while gaining your speed..

Unless I'm interpreting all this all wrong, I believe the whole transferring energy to and from the battery is to be avoided in pulse and glide because its inefficient.
there are energy losses as it goes into the battery as well as when it comes back out.

I don't know if you had a switch where you could totally disengage the hybrid part and simply use the ICE to speed up and pure glide to slow down, would be the trick or not.
But I don't think so.... there is a certain amount of benift derived from the ICE being on and charging the battery a bit so when you glide you get to use some of that...
But when you attempt to utilize the hybrid facilities to its limits is when you take it in the shorts.

Forgetting pulse and glide and talk about normal driving for a minute, the hybrid really pays off because there are tons of times when your kinetic energy must be wasted by braking and coasting to complete stops and then restarting momentum again.... in real life driving, some of that "what would be wasted" kinetic energy gets to be captured for later use thereby improving the efficiency of you overall driving experience.

But with Pulse and glide, you are turning our commuter plane into a glider... a bit of a different application.
You are on a flat surface and there is "no" kinetic energy to waste.... you want it all for the trip!

the moral of the story with pulse in glide "in my opinion" is that you can utilize some of its theory and application to your real life driving experience by avoiding changing speeds back and forth and avoid braking unless absolutely necessary and try to avoid pulling the battery down to near dead with EV mode unless you are puttering along and doing something the ICe really shouldn't have to do because the work is so easy, and keep your speeds low if possible.

Barring all that I just drive normal... I favor 70 - 75 alot and try to keep constant speeds if possible.....
I believe achieving maximum mpg is cool for fun, but should not become a bondage whereas you are afraid to turn on the air when its over 100 degrees for fear of using gas etc.

The wonderful gas mileage is not worth it if you have to arrive a sweaty pig or a popsickle because you wouldn't turn on the heat.
Even when you drive sensibly and keep you and your family totally comfortable, you still beat the pants of the best luxury cars with your worst gas mileage!.....

Some people live in moderate climates and can get away with no air or heat most of the time, but others need it to survive. In the south when buying a car, you open the hood and see if it has air, then you see if it has an engine!

[rufaro]

<div class='quotetop'>QUOTE(xxxlmpg @ Jun 7 2006, 10:15 PM) [snapback]267726[/snapback]</div>

Mo men tum
[/b]

Ok, thanks for the single syllables. But--WHY??? Don't I have the same mo men tum coasting w/ or w/out battery use? (Obviously not, but I don't see why </span> not...) <span style="color:#66FFFF"><_<

[Tripod137]

<div class='quotetop'>QUOTE(Rufaro @ Jun 8 2006, 02:27 AM) [snapback]267757[/snapback]</div>

Ok, thanks for the single syllables. But--WHY??? Don't I have the same mo men tum coasting w/ or w/out battery use? (Obviously not, but I don't see why </span> not...) <span style="color:#66FFFF"><_<
[/b]

How about this:

Since you mentioned green arrows, it means regeneration is taking place. Regeneration causes drag and makes you slow down (that's why they call it regenerative "braking"). Since this is all about MPG...."coasting" with regeneration....lets say...from 40MPH...you slow down to 30MPH in 200 feet (just an example..I don't know the real slow down rate...depends on the road too and some other things). Ok...40 - 30mph in 200ft w/ the green arrows (meaning you get drag). Now, with no arrows...actual coasting....you get no drag from the regenerative breaking system...so you go from 40MPH to 30 MPH in 500ft....You get to travel further before having to use the ICE (and gas) to get back up to 40MPH. So...you end up with higher MPG. The further you travel w/o using gas....the better, yes?

As a side note, if you are coming up to a red light, it only makes sense to let the regen braking do it's thing. It slows the car down (you need that anyway), it saves your brakes (nice thing to save on), and it recharges the battery. You are going to stop anyway...might as well make the most of it.

[rufaro]

[quote=Tripod137 @ Jun 8 2006, 03:30 AM) [snapback]267778[/snapback]</div>

How about this:

Since you mentioned green arrows, it means regeneration is taking place. Regeneration causes drag and makes you slow down (that's why they call it regenerative "braking"). Since this is all about MPG...."coasting" with regeneration....lets say...from 40MPH...you slow down to 30MPH in 200 feet (just an example..I don't know the real slow down rate...depends on the road too and some other things). Ok...40 - 30mph in 200ft w/ the green arrows (meaning you get drag). Now, with no arrows...actual coasting....you get no drag from the regenerative breaking system...so you go from 40MPH to 30 MPH in 500ft....You get to travel further before having to use the ICE (and gas) to get back up to 40MPH. So...you end up with higher MPG. The further you travel w/o using gas....the better, yes?

As a side note, if you are coming up to a red light, it only makes sense to let the regen braking do it's thing. It slows the car down (you need that anyway), it saves your brakes (nice thing to save on), and it recharges the battery. You are going to stop anyway...might as well make the most of it.
[/b]

By jove, I think I've got it! Now--who can tell me if the cops'll buy pulse&glide] stopsigns (I have lots more of those around town than lights...)...

[TonyPSchaefer]

Yeah. I think they've explained it well. RE-read Windstrings' explination a couple times and then come back to it in a couple days after your brain's worked on it for a little while. Of course, this isn't going to keep me from trying to explain it myself.

Anytime there are arrows, you are losing something. Period.

• When you're coasting and recharging your batteries, you're sacrificing speed and momentum to generate electricity. (you can feel the drag)
• When you're running on battery (stealthing) you're burning the charge to generate the movement.

Either way, you're giving something up in exchange for something else. Equivalent Exchange, the one true law of alchemy.

On the other hand, when you have no arrows, there's no drag on the wheels and the batteries are not being used. In this case, you are "free-wheeling" without sacrificing momentum or battery charge.

[Jim1eye]

[quote=Rufaro @ Jun 8 2006, 06:48 AM) [snapback]267781[/snapback]</div>

By jove, I think I've got it! Now--who can tell me if the cops'll buy pulse&glide] stopsigns (I have lots more of those around town than lights...)...
[/b]

If you are referring to what NY cops refer to as "California Stops", here's what they told us in the academy: "STOP means the cessation of movement." A ticket depletes what you saved on great gas mileage. So, you're on your own....unless, of course, you budget for such things.

[windstrings]

<div class='quotetop'>QUOTE(TonyPSchaefer @ Jun 8 2006, 05:57 AM) [snapback]267801[/snapback]</div>

On the other hand, when you have no arrows, there's no drag on the wheels and the batteries are not being used. In this case, you are "free-wheeling" without sacrificing momentum or battery charge.
[/b]

Yea, and there has been discussion as to why Toyota didn't just make it with no drag and no regen when letting off the gas "seems for efficient for the veteran prius driver right?".

But the decided to "simulate" the transmission drag of a normal car and make power in the process.
Most people "want" to slow down by letting off the gas and don't expect to have to apply the brakes.

Personally, I think anyone would get used to it quickly.
But bouncing from car to car as most families have several cars "not all prius's" it could gender a lawsuit if they didn't do it the way they are doing it.

I wish we could tell the computer to quit using regen for coasting and give us a choice... but not so yet.

Pulse and glide is basically trying to disable the regen function by feathering the gas pedal just a bit... you also get alittle benifit from the battery too when you do that because it was charged prior when the ice got you back up to speed.
As I said earlier, if you try and maximize the hybrid features by charging the battery aggressively and draining it aggressively, you will only be wasting power.
Ideal regen is only when you want to capture power that would have otherwise been wasted.

[sfr]

Stop? How about, as the locals say, a California Roll.

<div class='quotetop'>QUOTE(Jim1eye @ Jun 8 2006, 08:12 AM) [snapback]267970[/snapback]</div>

If you are referring to what NY cops refer to as "California Stops", here's what they told us in the academy: "STOP means the cessation of movement." A ticket depletes what you saved on great gas mileage. So, you're on your own....unless, of course, you budget for such things.
[/b]