My Method: "Pulse-Cruise / Neutral-Drive-Glide / Resume

[efusco]

<div class='quotetop'>QUOTE(orangeblood @ Mar 14 2007, 08:06 PM) [snapback]405782[/snapback]</div>

Hi Evan,

That's a hard concept for me to get my head around. I do understand that one could not P&G forever without the battery receiving enough charge to keep it at the minimum it requires. But let's say I have a nice long stretch where I can P&G and I'm trying to achieve maximum MPG for that stretch. Would it not be best to avoid having the ICE divert energy into the battery?

Otherwise, if I understand correctly, it's not so much understanding that it would be more or less efficient having a green arrow into the battery during the pulse, it's understanding that that condition generally tells me I'm in an efficient RMP range? If true, why couldn't I glean that from the instant MPG readout?

Sorry for the dense questions!

[/b]

Let me try to show by example...
Let's say that the amount of gas burned during a pulse period contains 100 EUs "energy units"....
With your method of pulsing w/ no arrows to the battery:
Lets say that 5 EUs were used during the glide (net loss 5 EU). During the pulse phase you burn your 100 EUs by very slowly pulsing.....b/c your pulse is so slow you're in a less efficient band (33% efficiency) for the ICE and it converts only 33 EUs to usable energy and all that goes to propel the car.

Now, with my pulse method:
I still use the 5 EUs to glide. But when I pulse and burn my 100 EUs of gas, but I'm doing it in the most efficient band...faster acceleration in the 38% efficiency range...thus I get 38 EUs of usable energy out of my 100 EUs of gas. So I'll used the same 33 EUs that you used to get up to speed, but I'll send my bonus 5 EUs back to the battery to replace what I used to glide....now, I may lose 1 EU in converting for battery storage, so I may still be net loss 1 EU to the battery, but that's better than your 5 EU for the same amount of gas used.

Obviously that's not exactly how it works, but it's a decent way to look at the concept.

[orangeblood]

<div class='quotetop'>QUOTE(efusco @ Mar 14 2007, 11:23 PM) [snapback]405794[/snapback]</div>

Let me try to show by example...
[/b]

OK, I can understand that example. But here are the complicating factors:

1. Trying it tonight, I found I could pulse back up quickly (or slowly) without sending a green arrow toward the battery. (The point being that pulsing back up to speed with "my" method does not require doing it slowly.)

2. The example in the link I originally referred to ( http://www.cleanmpg.com/forums/showthread.php?t=1224 ) shows the car pulsing back up to speed at several different rates of acceleration, also. (The point being that if a green arrow toward the battery indicates being in an "efficient band," there must be plenty of those at various rates of acceleration.)

If you don't feel like explaining further, I certainly give you a free "out" of this.

[hobbit]

This is getting back into the "deadband fallacy". Whether or not
current is sent to the battery or comes from the battery is largely
dependent on the state of charge, not what you're doing with your
foot during a normal pulse. If you pulse *really* hard you might
draw some from the battery to assist, but you need to get up over
like 3000 rpm for that and I think you'd know you were leadfooting
it. For normal pulse situations the currents in and out are quite
miniscule, but of course those stupid animated arrows don't show
you how MUCH flow is going on there.
.
So as you glide, even with the "zero arrows" thing, you're still
drawing 5 amps out of the battery. That's about the threshold
at which the orange arrow comes on or not. That will invariably
draw the battery down a little on a long glide, and so you'll see
more green arrow on the next pulse. That's okay, as long as those
currents remain small and you keep the SoC near or slightly below
its nominal "seek 60%" level. High currents and pulling it repeatedly
down into two-pink-bars territory will lead to inefficiency, since
you're converting more energy into electricity and chemical storage
and then back out again, incurring loss.
.
The only way to achieve zero battery current [and that's still not
zero, because you're still powering all the 12V stuff via the
converter] is pop into neutral. That switches off all motor
control. You'll find that you won't glide nearly as far as a
result -- that little allowable 5 or 10 amp trickle actually helps
quite a bit.
.
_H*

[sub3marathonman]

<div class='quotetop'>QUOTE(hobbit @ Mar 15 2007, 12:59 AM) [snapback]405883[/snapback]</div>

This is getting back into the "deadband fallacy".

The only way to achieve zero battery current [and that's still not
zero, because you're still powering all the 12V stuff via the
converter] is pop into neutral. That switches off all motor
control. You'll find that you won't glide nearly as far as a
result -- that little allowable 5 or 10 amp trickle actually helps
quite a bit.
.
_H*
[/b]

Yes, but now hobbit is confusing me. On 3/7 hobbit said:
What's the general speed range of your downhill? If you can start
it at less than 42 MPH and make sure the engine's off, and then
pop into neutral, the engine will stay off even if you get *above*
42 on the way down. That's a serious gas-saving state if you can
do it; just be prepared to pop back into D if you have to slow down
so you can at least get the regen.

I was thinking that I understood hobbit's neutral advice, since you're giving up the regeneration for greater coasting distance, while your battery is at a greater than usual state of charge. I was also wondering if it hurt the CVT to put it back in D after being in N to get the regeneration.

Obviously the difference is being on level ground vs. downhill, but it is still confusing. It still seems that you could coast further in N even on level ground, give up the battery losses, and still be ahead, although of course in real life it is highly impractical to do. Efusco's example however really was helpful.

[Mister Swigart]

I am enjoying this conversation going on here. I realized when I started this article that I was suggesting a way to achieve the same effect of a glide, though it was not -- by definition -- the same as the term used in the articles regarding the 109 mpg record. But my experimentation was to see if what I had been reading in those descriptpion was achievable or even applicable during everyday driving methods (which I do not feel the record represents with its two drivers, repeated stretch of road, in the absence of traffic conditions, and by careful monitoring of the screen.

I do not feel it is necessary even to have some of the questions cleared up that have been raised by the last several posts. I have avoided the use of "deadbanding" or "no arrow" whatever, as this quickly sets my battery down to the last two bars. I did not feel it was even necessary to avoid sending juice to the battery. Note: I am very colorblind, and even though I can see the different arrow colors, I have difficulty naming their proper colors, so I have asked my wife to identify the colors that I see as different values). When I perform the "glide" that I speak of, the engine is in Drive, the arrows are going to the battery, and they are a pale blue color according to my wife. I see that as a pale gray. In my travels, the battery totally jumps from being in dark blue bands to a "light green." I was not getting this charged battery signal ever from using neutral in my earliest experiments. If the loss of momentum that comes from "gliding" in Drive rather than "coasting" or "freewheeling" in Neutral brings such a benefit in terms of charged battery, I was willing to continue with a method that doesn't "deadband" for very long at any time. I realize that is a departure from the original non-traffic descriptions of Pulse-and-Glide.

I objected to this article being included here, by the way, under Fuel Econmy, as that was not what I was really trying to write about. I merely used the fuel consumption to bear out whether or not this method I have proposed was working. I am sure that it does work, is safe in traffic, and does charge the battery to a very high (and I will assume healthy) degree.

Now, almost all of the talk I read about here at the forums suggests that most drivers are using the Energy Monitor screen to see where arrows are coming from, going to, and what is "driving" what and getting what levels of instantaneous mpg usage. I am beginning to believe that in traffic, I would prefer to use the Consumption Screen as I can't afford to watch that closely or take my eyes from the road when closed in by so many others. So, I watch the speedometer, "feel" the engine, use the Cruise Control instead of the accelerator altogether, unless I have come down below 24 or 25 mph and have to bring it back up to Set the next Cruise phase. One of the posters above suggested that I keep the rate of acceleration (how aggressive it is) minimized by watching the fuel consumption and not accelerating so rapidly that I fall below 25 mpg at any moment. This is proving to be pretty good advice. So, using the Consumption Screen with its columns and little green cars (and I get large stacks of cars in my columns), I watch the road, glance at the speedometer, and alternately glance momentarily to the current miles per gallon shown by the column at the far right of the screen. I try to keep my acceleration as close to or above the 50 mpg line as possible. When I kick up the Cruise Control level to accelerate (pumping the handle toward the ceiling), I try not to do that so fast that my column on the right falls. If it does, I come off it by pumping down on the handle toward the floor so that I maximize the amount of time the car is kept at or above the 50 mpg level. This way, I do not have to watch very closely and can just "feel" how close I am to keeping a midline column at any time, or higher to 99.9 mpg.

I am still right at 51 mpg plus or minus .3 of a gallon. That is an indicator that I'm doing something right. I think that some of the highmilers here are not willing to try something other than what is working for them in fear of losing their great averages touted by their Green Mile Stickers. I can't blame them, of course, but I would like to see some of you experts give this a fair testing to see what it might really be worth. If a newby can get 51, what might a "senior Prius user" get? Tomorrow morning . . .

The Lone Ranger
Rides Again!

[orangeblood]

<div class='quotetop'>QUOTE(The Lone Ranger @ Mar 16 2007, 12:07 AM) [snapback]406515[/snapback]</div>

I am still right at 51 mpg plus or minus .3 of a gallon. That is an indicator that I'm doing something right. [/b]

Hi Lone,

Regardless of what all has been discussed in this thread (and it's been a lot), you should know that you will achieve much higher MPG by learning a true glide. I think you still have a misunderstanding of this. (I'm saying this helpfully, of course, and not in a critical way.)

A real glide is also safer in traffic because it's a much more gradual slowing down. And thus you don't have to start up your pulse as quickly. The very fact you are avoiding "deadbanding" is actually hurting your mileage. But don't worry, you are doing great and you will eventually pick up on this.

On a related note, these past couple of days I've been employing the pulse method referred to in this thread of trying to keep a green arrow flowing into the battery. I must say, I'm quite amazed with the results. After several 30-minute commutes (both highway and city streets) most every 5-minute bar is over 50 mpg, and my tank average is over 55 mpg. Now, even though I had a 62.3 mpg tank last summer, this winter has been the doldrums, with most coming in below 45 mpg. So this recent 55 mpg tank is quite a signficant improvement.

I love learning more about this stuff!

[Mister Swigart]

<div class='quotetop'>QUOTE(orangeblood @ Mar 15 2007, 10:12 PM) [snapback]406559[/snapback]</div>

Hi Lone,

Regardless of what all has been discussed in this thread (and it's been a lot), you should know that you will achieve much higher MPG by learning a true glide. I think you still have a misunderstanding of this. (I'm saying this helpfully, of course, and not in a critical way.)

A real glide is also safer in traffic because it's a much more gradual slowing down. And thus you don't have to start up your pulse as quickly. The very fact you are avoiding "deadbanding" is actually hurting your mileage. But don't worry, you are doing great and you will eventually pick up on this.

On a related note, these past couple of days I've been employing the pulse method referred to in this thread of trying to keep a green arrow flowing into the battery. I must say, I'm quite amazed with the results. After several 30-minute commutes (both highway and city streets) most every 5-minute bar is over 50 mpg, and my tank average is over 55 mpg. Now, even though I had a 62.3 mpg tank last summer, this winter has been the doldrums, with most coming in below 45 mpg. So this recent 55 mpg tank is quite a signficant improvement.

I love learning more about this stuff!
[/b]

Hello Orangeblood,
Thanks for giving "Pulse-Cruise/Cancel-Glide/Resume" a try. Believe me, I'm not trying to avoid deadbanding. I'm just not willing to watch the screen and pedal up and down while watching to see if I'm getting it. I don't feel it in the seat of my pants as one put it, so I do it this other way. Note: once in a while when there is no one behind me or just in front of me, I check both screens to verify what I'm learning. I do get deadbanding frequently, especially when on Cruise Control but pumping down on the rate using the handle at those moments I described in the last post where the right column on the consumption screen falls, I pump down, and it rises back up well over 50. The Cruise Control is still on call, but effectively I'm gliding without a call on gasoline and neither from the battery, no colored arrows whatever -- in other words, I'm not doing Cancel-Glide but pumping down to slightly lower Cruise levels, essentially the same as coming off the gas with your foot and apply just a touch of pressure, again. I'm paying attention to this more and more. This is when I'm getting the true glide, only, I'm doing it with my foot off the gas and using the cruise control which is on this car, really, a hand accelerator (as a matter of fact, the symbol is a small dial like a speedometer, appropriately). I have no doubt that many of you can do this with your foot, but I do not have the touch. Perhaps after the long travels I'm planning for this summer will give me the opportunities to study and learn this, better. In the meanwhile, I'm sticking to this game plan, and inviting others to add to my short, and limited knowledge. I look forward to hearing more about your results. You're doing better than I, which is what I thought would happen. I would like to get Evan to try this, as well. I'm not feeling so much like . . .

The Lone Ranger
Rides Alone.

[ken1784]

<div class='quotetop'>QUOTE(sub3marathonman @ Mar 12 2007, 01:12 PM) [snapback]404018[/snapback]</div>

Somewhere else I believe it was hobbit who said to accelerate at no greater than the rate that gives about 25 mpg instantaneous on the graph. That is a bit aggressive, but not flooring it.
[/b]

The best shift of the famous 109 mpg 1400 mile marathon run recorded 9.84 km/L (23.1 mpg) for engin on mileage (pulse or acceleration part) and 19% engine on distance, so they glided the rest, 81% distance.
The result of the shift was 51.25 km/L (120.6 mpg) for 150.78 km (93.7 mile) distance.
http://www.greenhybrid.com/discuss/showpos...mp;postcount=77

Ken@Japan

[sub3marathonman]

<div class='quotetop'>QUOTE(The Lone Ranger @ Mar 15 2007, 11:07 PM) [snapback]406515[/snapback]</div>

So, using the Consumption Screen with its columns and little green cars (and I get large stacks of cars in my columns), I watch the road, glance at the speedometer, and alternately glance momentarily to the current miles per gallon shown by the column at the far right of the screen. I try to keep my acceleration as close to or above the 50 mpg line as possible.
The Lone Ranger
Rides Again!
[/b]

On the "Obscure Facts" thread I mentioned that the most little green cars you can get are four. If you are seeing that many you may actually be regenerating more than that. Also, while they do look great on the screen, the real goal is to regenerate as few little green cars as possible, since each one represents a deceleration and you then have to accelerate again.

And also, as ken1784 has pointed out, accelerating at the 50 mpg line is probably a bit too slow. I must give you credit for being that gentle on the acceleration though, which I think is the accepted method of maximum milage for ordinary cars.

[bruceha_2000]

Hi Ranger,
I applaud you your desire to experiment
As noted by others, foot off the accelerator will slow the car faster (while charging the battery a little) than a 'no arrows' glide which neither uses the battery to power the electric motor nor adds power to the battery via electrical generation. Since you are new to the car, I think you should not give up on the 'feel it in the seat of of pants' detection of glide vs watching the screen. These things are all subtle and take time. You can kind of feel it 'let loose'.

I think there is some serious calculation going on inside the car's computers when deciding how much engine and how much electric motor to put in the mix at any given point in time. Again, as noted earlier, the state of charge of the battery plays a big part in this. I have been on the interstate where the car might be using ALL electric (according to the arrows) on a slight up hill when the battery is 7 green bars (of 8). At the same point, I have also seen it being all ICE or a combination of ICE and adding excess to the battery when I am at 5 or 6 blue bars.

One thing you have not said (at least I didn't see it) is how much of the time you are in "electric only" while employing your technique. I would guess that you are charging the battery whether in pulse or regen coast and not likely in 'all electric' much if ever. Or maybe your pulse is getting better MPG because the electric motor is being used more with a high battery SOC? For general 'town' driving, I find that the electric motor has reasonable power, the only thing holding it back from doing all the work most of the time is the relatively small amount of battery capacity.

You mentioned tapping the CC stalk to raise your speed. If you haven't found it elsewhere, the CC is very nice about increasing speed by exactly 1 MPH for each tap. I think you are providing a manual 'adjustment' to the aggressiveness of the CC. If you had dropped from 40 to 30 then hit resume, it will try to get up to 40 based on some acceleration formula. By tapping the CC stalk, you are asking for a LITTLE increase so it doesn't calculate as high a rate of acceleration. Of course, your orignal premise was a less 'hands/foot on' interaction. Don't have to watch the screens or hold your foot just so on the accelerator.

One variable I don't think you have stated: How flat/hilly is it where you drive? Also, are you doing these tests with an 'overnight' cold engine? On short trips (1 or 2 miles)? I pretty much never do better than 35 MPG in the first 5 minutes. Thus those short trips will dash any hope of breaking 50+ on a tank.

I think you have already seen that temperature plays a big part in MPG. We see a serious improvement when the temp goes over about 35F. Of course it is well below that most of Dec through Feb. and we feel that pain! On an specific 8 mile trip with few stops, posted mostly at 30 MPH, I can get half the distance (total, various up and down hills along the route) on 'all electric' when it is 50+ F but NONE when it is 20F.