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I've been working on a document (http://techno-fandom.org/~hobbit/cars/HSI/) about the "hybrid system indicator"
in the third-gen Prius, slightly ironic as I don't actually own
one but have just enough time in one to see a lot of parallels
in running-condition thresholds to my own '04 and how I read
its add-on instruments. It's been mostly going on over at
Priuschat (http://priuschat.com/forums/x/66411-hsi.html) but I figured if a few folks here hadn't seen it yet
and are interested in helping refine the info, I'd drop another
reference thread over here for y'all.
.
_H*

Hi Al:

___I would hold off a bit as the HSI is more of a bad mimic. There are differences between going up and down into the threshold and it also depends on speed. The Prius-III is a mess between 42 and 45 mph and the high FE capability of P&G at speeds below 35 mph is not as high as it is with the Prius-II.

___Good Luck

___Wayne

Hi Al:

___A few more details...

http://www.cleanmpg.com/photos/data/523/51_mph_-_IGN_22_-_TPS_19_-_1107_RPM_-_83_mpg.jpg
http://www.cleanmpg.com/photos/data/523/52_mph_-_IGN_22_-_TPS_19_-_1114_RPM_-_71_mpg.jpg
http://www.cleanmpg.com/photos/data/523/55_mph_-_IGN_22_-_TPS_19_-_1088_RPM_-_78_5_mpg.jpg
http://www.cleanmpg.com/photos/data/523/56_mph_-_IGN_21_-_TPS_18_-_1088_RPM_-_91_6_mpg.jpg

___Good Luck

___Wayne

Good stuff, Hobbit.

Appreciate the link.

You can't really judge by the instantaneous that way, I don't
think. Again, getting a monitor on a fuel injector line and looking
at open times [even just with a scope if we can't get the right
bits for a scangauge] will tell the true story on where "loaded"
really begins. But from what I felt and saw for LOD I really
think it starts about where you've got the HSI in most of those
shots. You also can't try to do any of this under cruise-control;
it's all way too variable in terms of where throttle control
winds up.
.
_H*

Hi Al:

___This was the best I could do after 1,800 miles, not a short jaunt down a local Interstate. This was also not with CC but a DWL scenario after an 8% SG-II offset was in place.

___We have discussed WS entry and exit as well. An SG-II will show a steady RPM in the high 980 range IIRC but about half way up the EV side of the HSI and she moves into an injector on like WS for some reason?

___Coming down through 45 mph, to evoke ICE-Off, let off to regen and than move to N will force it. Drop below the threshold and she is bouncing back and forth between ICE-On and a WS like ICE-Off. Very strange.

___Around town, P&G and SHM work as expected but the FE capability on the top end and bottom end are not as high as the Prius-II. Napa Valley’s 90 + was really mid-80’s with a 20 mph avg. speed? The Prius-II would be up into the 100’s on that route. From Chicago to New York and back allowed 800 + miles on a single tank both ways but not at 70 + like the Prius-II. It was 65.9 (actual top off to top off) and I was working it albeit with a light headwind heading out and a stronger headwind coming back.

___I have pics all over the place of this stuff but need to bring them altogether...

___And that damn 6 mpg over report by the aFCD :rolleyes:

___Good Luck

___Wayne

Hi Al;

I totally agree with Wayne on this one.

Contrary to what many folks at PC believe (Including Ken & others) the HSI is not a tool I would trust at all in part because at best all it shows is the "power/energy requested" and not the "actual power/energy being used".
With this said, I will only use it when I need to manage my SoC by keeping the EV amplitudes and regen's to a minimum. On this front it is a useful gauge for me. On all other fronts (including the so-called P&G execution), I find it of limited to no use.

Cheers

MSantos

I agree that there are some fairly well-known hysteresis effects in
all variants of the Prius, which is in fact one reason P&G works
when the driver forces hopping across those inefficient states.
But it sounds like my whole effort is being dismissed as wrong.
I said straight out that the HSI is not linear and heavily
affected by SOC and probably some other factors; it's not just
a fixed "mimic" of driver demand or something like that.
.
As far as I'm concerned the mid-speed problem with the Prius has
been solved long since, and it's just a matter of finding out a
few new specifics for the 3rd-gen. Yes, various readings are
"all over the place" -- iFE, for example, is *very* twitchy at
the low end of "loaded", showing anywhere from 50 to 80 mpg in
my car too, but for discernible reasons -- RPM changes a bit,
injector time widens or shortens; I see all that going on too
and have learned to play it reasonably well in my own car. I
just got back from a long one today showing 61.5 mpg over 500
miles, all highway with some rain, and I wasn't coddling it --
in fact going 65+ MPH for a healthy chunk of that time [mostly on
the downs]. That's not a bad showing for what more people would
accept as real-life travel speeds, I think.
.
Rather than suggest "holding off" on something already for the
most part published, how about detailing which parts you [xcel]
consider inaccurate, and offer some input for fixing it and
providing a solid document for the masses? What is your number
one display to monitor in a Prius, and why, and where do you
try to keep it? What was your primary efficient-running indicator
for, say, the Chi-to-NY run? The iFE? Something on the scangauge?
How do YOU define "DWL" in a Prius, as the physical throttle is
completely divorced from the driver's foot?
.
I think as people come to understand that thresholds and targets
can change quite radically in a running Prius, they'll learn to
understand what the HSI is telling them better. Your very own
example of falling out of WS at different thresholds is well-known
and detailed at length in my existing WS document, and I don't
expect the 3rd-gen behavior to be particularly different. I'm
confident that the 42 - 45 mystery area will be solved before
long, too.
.
_H*

Hi Al:

___I have to get some sleep but there are more than a few problems. It is not about what your car can and cannot do as we have been through all of that before. SHM while DWL on the highway for 70 + mpg's in a Prius-II. Regarding WS, that doc does not match the Prius-III either. You have to drive one with an SG-II to see the strange ICE-On/ICE-Off behavior between 42 and 45 either going up or coming down let alone above 45 and the WS changes. The Prius-III is nothing like the Prius-II when it comes to WS. This is also not about efficient or inefficient areas but simply achieving what many PC’ers never seem to be able to do and that is punch the damn thing into the 100’s around town and 70 + on the highway.

___Some of those guys tend to fool themselves into believing they both understand and know how to achieve what we do here daily but it is our job to stop the mis-information before it gets started as it confuses the new and future Prius drivers. I do not want to spend the hundreds of hours to remove the non-sense that some of those guys coerce others into believing just like we had to do with the Prius-II! It is bad enough that a strong core group of PC's include numbskulls that are attempting to redefine what Hypermiling is after both Manuel and Mike Sefton tell them exactly what it is without question. Let alone how the Jetta TDI performs when none of them have even driven one yet still for some reason know more than those of us who have :confused: I simply do not want to go there and you are moving awfully fast with this...

___Regarding 65 + mph, your average speed was probably more around 55 or so.

http://www.cleanmpg.com/photos/data/523/48_6_mpg_over_32_3_miles_of_all_highway_at_65_mph.jpg
I was in the car but most certainly not at the wheel when Danny of PC
set the cruise at 65 mph yet a few slowdowns to turn around turned it
into a 50 mph avg speed.

http://www.cleanmpg.com/photos/data/523/65_4_mpg_over_102_3_miles_of_all_highway_at_50_mph.jpg
And my DWL around the 50 mph avg speed mark including five
off-ramps to find the same station I did the intial top off fill at.

___Both of these results occurred in almost freezing temps and at night on our way to and from Sacramento, CA back to the NAPA Valley area.

___The new Prius-III doesn't really allow the slow speed stuff to get in the way w/ the avg speed staring at you and here is a result of a 60 + mph run from Chicago to well into NY before stopping for the night. The avg. speed ticked down from 54 mph to 53 mph while driving around Harry Clark’s home looking for a parking place.

Chicago to NY

http://www.cleanmpg.com/photos/data/523/555_5_miles_-_70_9_mpg_-_53_mph.jpg



From NY to Chicago

http://www.cleanmpg.com/photos/data/523/2010_Prius-III_at_a_rest_stop_with_Flags_blowing.jpg
From NY with a 10 + mph headwind most of the way home as shown with the flags at a rest area.

http://www.cleanmpg.com/photos/data/523/55_mph_-_IGN_22_-_TPS_19_-_1088_RPM_-_78_5_mpg.jpg
Achieved with average highway speeds of around 52 mph into that damned head wind... which includes a downtown
stop near Erie for ALS to take a slow speed suburban and higher speed highway test drive, a rest stop every hour
or so including three for breakfast, lunch and dinner.

___The Prius-III SHM numbers are posted as shown as are the speeds so that is not the issue we are talking about.

___What I want you to be very careful with is the rates of acceleration or efficiency areas via HSI. I usually run from the threshold bar up to underneath the ECO bar and that will give 91.1 mpg around town with lights, with traffic, with impediments and with a warm-up hit over a scant 4-miles as I did this just a few hours ago in my parents 2010 while going out to dinner with them. Subtract the std. 6 mpg over report and you may find that the higher rates of accel with the HSI closer to the PWR end "may" lead everyone in the exact wrong direction. We do not need any of that 1,700 RPM stuff that the PC'ers were all hung up on for years when we were using lower R's and achieving far better results. This is the reason I said be very very careful when referencing the HSI for a rate as what you posted is not what I have experienced to maximums albeit traffic dependant in some cases so far.

___A quick trip in a spare and not setup 2010 Prius-III around Rochester, MI while at the HS 250h launch a few months back.

http://www.cleanmpg.com/photos/data/500/83_7_mpg_over_3_1_miles_at_42_mph_and_99_9_mpg_combo.jpg
The 83.7 was after coming off the Interstate to a stop and than making a corner when I snapped
the pic. The aFCD was at 79.x mpg and Avg speed was 48 mph whenI exited. -- The 99.9 mpg
was with an avg. speed of 25 while I circled the motel parking lot in EV to find a place to park.


___Here is some more while coming through the morning Chicago Rush headed home...

http://www.cleanmpg.com/photos/data/523/8-miles_past_the_Dan_Ryan-Kennedy_Junction_TOTAL.jpg
8-miles past the Circle (downtown Chicago)

http://www.cleanmpg.com/photos/data/523/9-miles_past_the_Dan_Ryan-Kennedy_Junction_TOTAL.jpg
9-miles

http://www.cleanmpg.com/photos/data/523/13-miles_past_the_Dan_Ryan-Kennedy_Junction_TOTAL.jpg
12.7 miles

http://www.cleanmpg.com/photos/data/523/14-miles_past_the_Dan_Ryan-Kennedy_Junction_TOTAL.jpg
14.3 miles

http://www.cleanmpg.com/photos/data/523/16-miles_past_the_Dan_Ryan-Kennedy_Junction_TOTAL.jpg
16.4 miles

http://www.cleanmpg.com/photos/data/523/28_5-miles_past_the_Dan_Ryan-Kennedy_Junction_TOTAL.jpg
28.5 miles

http://www.cleanmpg.com/photos/data/523/44-miles_past_the_Dan_Ryan-Kennedy_Junction_TOTAL.jpg
44 miles

http://www.cleanmpg.com/photos/data/523/72_8_mpg_over_815_9_miles_at_44_mph.jpg
Final at home when filling up that night.

___Subtract the customary 6 for some reasonable actuals.


NAPA Valley FE challenge

http://www.cleanmpg.com/photos/data/523/Untimed_Challenge_-_94_6_mpg_at_19_mph_avg.jpg
An untimed challenge through stop lights, signs and Rush hour around Napa Valley.

___And subtract the customary 6 for a reasonable actual.

___All I am saying is be very very careful with how you present the HSI for Max or near Max FE. Right now, the Prius-II can dominate the Prius-III on the highway and around town in my few thousand miles with the 2010. I need some more time in one for the low speed stuff to figure out some decent rates and ranges and I highly suggest you spend some quality time in one as well. Until you begin to see these kinds of pics from those at PC having this discussion, I would be very leery as to what any of them have to say about near or peak maximums as the Prius-III is simply to new and none of us (imho) have the experience needed for a succinct document just yet. Any guide like the one you built already includes holes with the little experience I have in the Prius-III and I would prefer you wait until this gets sorted out by those that push the Prius-III to max either here or over at PC over the next few months.

___Good Luck

___Wayne

The document is out there, and it is useful for people to know not to accelerate into the power band, and not to accelerate ICE-off, etc. Furthermore, most Prius owners will not have Scanguage or CanView, etc. They need something.

That said, the caveats in the draft could be expanded to state that the best mileage may come from the lower end of the acceleration rates presented based upon the preliminary results of xcel. Also, that more work is needed and extra instrumentation will be needed to really max it out once the work is done.

Traffic and resistance to hypermiling will keep many from achieving elite mpg even after all the optimums are known. But no reason I see not to tell folks that there is a real drop off in the power band, etc. Mention avoiding cruising in the 42-45mph range?

It's very interesting when two fuel economy heavyweights slug it out...

I think that's one key to it, and will make that change pronto:
staying at the *lowest* practical end of the engine sweet spot
is a major key to the really high numbers, but wandering around
more toward the higher end may still return some reasonably
good results for drivers who aren't going for the total gold.
This is also entirely true in the second-gen, where I can confirm
Wayne's observations that the entire "loaded RPM" scale shifts up
and down with car speed and staying down around 1100-1200 during
takeoffs is just fine and keeps the numbers high. It's hard to
do that getting onto an interstate, though; if you can then that's
one of the things I mean about the "shoulders" of a segment.
.
I agree about more quality time at the helm of a third-gen but
I'm not sure where that's going to come from. I haven't even
*seen* any around my area yet [not that I've been there a whole
lot over the past month, heh] -- besides hybridfest, I spotted
my FIRST one in the wild only about 5 days ago and that was on
I-71 in *Ohio*. As unbelievable as that sounds, that's been my
view on third-gen deployment so far!
.
_H*

I've owned mine for 10 days and it takes some work for me to gain .1 mpg each day.

I have to order a new Scan guage because the HSI is driving me crazy. I hit 49.5 and it just plateaued. From 49.5 to the 50.4 has been a whole lot of work to achieve.

Short trips less than three miles, steep hills and the EV button at times getting locked out because the engine needs to restart at the absolute wrong time.

Plus I've been pissing off a whole of people around me when I'm running around on battery power. Eventually I do get up to the speed limit. :woot:

ALS, I'm surprised you are using EV mode on the streets that much. I would think just inducing glides w/ the go pedal and generally letting the car decide when to kill the ICE would improve results in many cases. Can you describe your EV mode usage?

Along with that question, are you using neutral to avoid current draw/usage while in a glide?

The one thing that neither of you have addressed is the apparent tendency to deny fuel cutoff even in full regain at high speeds. I don't now why it does it, but it just does and it does it a lot.

Hi Jud:


We have discussed WS entry and exit as well. An SG-II will show a steady RPM in the high 980 range IIRC but about half way up the EV side of the HSI and she moves into an injector on like WS for some reason?


You have to drive one with an SG-II to see the strange ICE-On/ICE-Off behavior between 42 and 45 either going up or coming down let alone above 45 and the WS changes. The Prius-III is nothing like the Prius-II when it comes to WS.
___Good Luck

___Wayne

The only time I have used neutral is when I'm on a slight grade and I shift into neutral to drift back. This way I don't have to put up with the back up beeps.

Give it a try for glides -- you eliminate any possibility of current flows to/from traction motor this way and can manage your SoC a bit more easily.

___And that damn 6 mpg over report by the aFCD :rolleyes:



When I first had my 2007 Prius II, the display also exaggerated 5 to 6 MPG higher than actual tank-top-off. After a year, the display got closer to actual top-off.

Was there any change in characteristics in terms of when to P&G, when to WS? I am so use to my Prius II and afraid the 3rd Gen takes away my freedom to interact with the mechine.

New York City has the worst combination of all bad conditions: traffic jam, cold weather/rain/snow, short trips, insanely angry drivers... But I got 28MPG to 75MPG in the city, 48MPG to 65MPG on highway. I had a lot of short, cold runs under slower-than-walk traffic. [Life time average: 42 MPG] Will the 3rd Gen offer better FE for my condition? I am more concerned about the lower end which dragged down my overall MPG.

Also, I park in the streets with less than an inch front and back! I really need the backup camera. Does the 3g offer backup camera?

There is no bladder in the gen III's to cause inconsistencies. This is in the programming.

There are substantial differences in the GenII compared to the GenIII concerning ws and pulse and glide.
I'm not sure about the type of traffic you are talking about

The back-up camera is available if you have Navi in the Gen III.

Good stuff guys!

Give it a try for glides -- you eliminate any possibility of current flows to/from traction motor this way and can manage your SoC a bit more easily.
In most case, that is correct. When you are decelerating, there will be a current flow into the pack when you get to around 32-33 mph and will last until around 30-31 mph. Also, if you are going downhill in neutral, current will start flowing into the pack at around 32 mph and will continue to do so until around 37 mph. I have seen +15 amps going into the pack while in N.

That's cool, Larry -- I didn't know that!

I forgot to mention that I have recently found that if you start a downhill N glide at 33 mph, the current won't flow into the pack up to the 37 mph threshold. I have found that it's worth it to burn just a tad more fuel and enter those types of glides a little bit faster(33mph or above) because you can glide significantly farther due to not having the drag of pack charging. It really stinks if you don't enter fast enough and the hill isn't steep enough to exceed 37 mph.:(

Waitasec, are you talking about a second-gen with this mystery
charge in *Neutral*?! I'm not buyin' that, and I would have
trouble believing it for a third-gen since that violates the
definition of how Neutral works in any Prius. I would have to
see that on an analog current donut, which I can 100% confirm
I've *never* seen in my so-instrumented car.
.
_H*

___This was the best I could do after 1,800 miles, not a short jaunt down a local Interstate. This was also not with CC but a DWL scenario after an 8% SG-II offset was in place.

___And that damn 6 mpg over report by the aFCD :rolleyes:

___Wayne
Wayne,

I'm a newbie to both Prius and Scangauge, so forgive me if I am a bit off the main topic of this thread.

Once the scangauge is set up for the 2010 Prius, does it estimate mpg more accurately than the gauges on the Prius itself or does it show the same inaccuracy?

Waitasec, are you talking about a second-gen with this mystery
charge in *Neutral*?! I'm not buyin' that, and I would have
trouble believing it for a third-gen since that violates the
definition of how Neutral works in any Prius. I would have to
see that on an analog current donut, which I can 100% confirm
I've *never* seen in my so-instrumented car.
.
_H*
I have seen it numerous times in my '07 since I first discovered it last summer. I have the SG set to monitor the current into/out of the pack with the BTA X-gauge. When gliding in N at 31 mph or below, the current is reading .9-1.0+ amps coming out of the pack. When you approach 32 mph, you see the current draw slowly drop and, as the speed increases, it goes to a negative value (charge going into the pack) and there is a very noticeable drag that feels like a brake dragging. At 37 mph, the drag is at it's highest and the current going into the pack is highest at -15 amps and above. As the the speed hits 38 mph, there is a sudden decrease in drag and the current value shifts back to the standard .9-1.0+ range.

...
Once the scangauge is set up for the 2010 Prius, does it estimate mpg more accurately than the gauges on the Prius itself or does it show the same inaccuracy?

My experience shows that on a per trip basis the scangauge tends to be a bit more realistic than my 3rd Gen's displayed FE. But while it appears to be more realistic, it still overestimates the FE by a tiny margin... especially when measured against the calculated FE at the pump.

Cheers

MSantos

Waitasec, are you talking about a second-gen with this mystery
charge in *Neutral*?! I'm not buyin' that, and I would have
trouble believing it for a third-gen since that violates the
definition of how Neutral works in any Prius. I would have to
see that on an analog current donut, which I can 100% confirm
I've *never* seen in my so-instrumented car.
.
_H*
Buy it. I know it makes no sense but I see it too. I documented it here (http://priuschat.com/forums/gen-ii-prius-technical-discussion/50385-discussion-gliding-comparison-methods-pedal-control-vs-neutral.html), fourth chart. If you're not seeing it with your analog instruments, I suppose an argument could be made that it's artifact of some sort within the CAN data stream. But like Larry, I feel it too on a steep hill as the momentary drag it produces suddenly lets go at about 37-38 MPH. I would say it feels more like momentary slipping into regenerative coasting rather than brake drag; it's very subtle.

Try it for yourself. Find as steep a hill as you can, which makes it most noticeable to the butt sensors. That also makes it short duration, so watch the instruments closely.

I tried neutral on my way to work today and I can't believe how far this car will coast.
I guess .40 Cd vs .25 in the Prius does make a huge difference. There is one section on my way to work about one mile long that has a small hill that levels out to flat section then back to another downward grade to a flat section with a slight downward grade all the way to my companies parking lot. Usually in the Volvo wagon I would have to engage the clutch tap the gas in the first flat area for a second or two to keep the car at 25 mph so I didn't drop into teens. Not with the Prius in neutral it stayed at twenty five all the way through that section. :Banane06:

Is coasting in neutral safe for a 2010 prius? I'd like to try it but afraid to cause any problems

And difference between .26 Cd and .17 is just as impressive. I've been driving my Dad's 2007 Prius while my car is in the garage getting the engine swap. I've been driving the same routes and speed profiles that I do in my aerocivic, and when in neutral his Prius has about the same coasting performance as my car does on a 0F winter day dispite the Prius' 800 lbs weight increase over the aerocivic. The faster the speed, the greater the difference. I haven't checked the tire pressures yet (they are probably where the Toyota technician sets them), but I will run them up to max sidewall and see if that improves the coast.

Yes, it is safe to coast in neutral in any Prius.

Mike, if the pressures are low inflating the tires more will make a significant difference… but it won't ever come anywhere close to your Aerocivic. :)

By the way, is your engine swap purely for mileage benefit or is the original finally wearing out?

By the way, is your engine swap purely for mileage benefit or is the original finally wearing out?

The engine is still running fine dispite low compression and burning some oil. Also 1st gear is starting to get a bit noisy. So the swap is partly for mileage and partly for parts wearing out.

Okay, Larry, Jimbo -- you're right, but you're not entirely right.
I spent a little time on my favorite Rt. 2 hill today in sparse
Sunday traffic, with my SG set up for *both* types of battery-current
xgauges just to be sure. That's the active-query one, which I assume
you're referring to as "standard" BTA, and the passive-CAN one which
is very fast. I had those two and my analog meter to all cross-check
each other.
.
The active-query OBD-II based BTA xgauge is *very* slow, and if it
happens to get an answer during a transient unusual peak it will
make you think that all kinds of crazy stuff is going on. The
passive one I use, 0030 / 0100 823B 0000 / 140C / 0001 0001 0000,
has the 12-bit-quantity wraparound problem and indicates 409.6 and
down for "negative" charging current -- but it's good enough as a
VERY fast indicator if you watch the numbers dance around, probably
faster than my analog meter. Presumably a correct interpretation
of this is what your CANView battery-current figure is based on,
too, but I don't know how fast Norm updates that.
.
And as I coasted in N from about 30 to 35, I saw the same little
"charging" peak you've described. All three devices registered
it, with varying degrees of usefulness. I used a little bit of
physical braking to not build speed quite as fast as the hill
might have taken me, slowing the events down.
.
On my first run, I watched the analog meter really closely. I
can barely see the tiny tickle of the normal 1.5A flow to keep
the DC/DC alive, and as I went through 31 or 32 MPH I saw a
gradual return to zero, slightly past it, and then current blipped
right back up to normal. We're talking a couple of millimeters
of deflection here, but I saw it. I sat there thinking "well,
whaddaya know, they're right" as I've never noticed that little dip
before. On a couple more runs I confirmed this with the passive
current xgauge -- the normal 1.5 A gradually came back down toward
zero, I saw a brief period of "40x.x" rapidly changing which indicated
a little bit of charging, and then it was all over the place in the
mostly-positive from then on -- much less stable than the quiescent
base load. This is what your graph shows, too. Active-query BTA
was just about useless to capture these very small short-term events.
.
However, it's not really regen-drag as such, and the energy under the
envelope of what's going on is nowhere near significant enough to
affect the N-vs-foot-control gliding issue.
.
This is implicitly explained in my "VH" subsection (http://techno-fandom.org/~hobbit/cars/ginv/VH.html) about the inverter.
I have a chart of a late-night coast-down on this same hill, and
you'll see that right above 30 MPH is about when the boost converter
starts becoming active. And it does so rather suddenly, jumping to
a fairly high level. What's happening is that as a certain speed is
reached, the peak generated EMF from one or the other motor gets high
enough to start pushing its way through the diodes to the battery.
Probably MG2, but who knows -- after planetary ratio conversion, their
curves are close to the same. The hybrid controller senses this, and
fires up the boost converter to keep the motor rails out of the way of
the back-EMF. So what we're most likely seeing, especially as I clearly
observed a gradual sinking past 0 amps and a fairly sudden correction,
is the stray MG voltage cresting whatever the battery voltage happens
to be at the time -- usually around 230 in real life at nominal SOC --
and the car going "oops" and compensating for it. Note that the
boost converter can still be active while in Neutral but the actual
motor transistor racks cannot, by definition, and enforced by the HV
ECU dropping both of the GSDN and MSDN shutdown leads to disable IGBT
switching. Running the boost converter takes a little bit of power,
which is why battery current starts getting much more random after
the converter turns on and keeps floating the rail voltage above
where the back EMF would be.
.
If this had ever produced a *sustained* 15 amps of charge current,
I would have definitely noticed that long ago. As it is what I see
on the analog meter during this is down in the noise of the physical
needle being bounced around a little by the car going over bumps.
Next time I'm on a nice steep downhill I'll try letting gravity
do a *faster* acceleration and see if the blip is higher before
the car realizes that it needs to up the voltage and not have
uncontrolled charging currents going on. This, by the way, is the
*other* reason for having the buck/boost converter in the first
place -- to deal with the much higher voltages that the series-wound
MGs can produce. Although it's still a mystery what happens at
really high speeds when the back-EMF envelopes are theoretically
above 500V. Even at 68 MPH warp-neutral, when I've been watching
for it, I've never seen any stray charging. I have no idea how
that's suppressed.
.
This has strayed way off the HSI and its nuances, but I *had* to
go verify the Neutral thing and figure out the cause. Thanks for
helping tie together some additional bits of knowledge, nonetheless!
.
_H*

Al, when you do those tests, you need to find a hill that will take to only the 36-37 mph level. I have noticed the highest currents when the hill just isn't quite steep enough to pass through the 37 mph threshold.

Party time! Larry, you and I actually taught Hobbit something!! ;)

Now, Hobbit, if only I can digest everything you're saying. I need to go back and study your link and what you're describing here about the boost converter to fully digest it all. Regardless, you've helped solved a minor mystery that has been lingering (with me) for over a year. Thanks for following up and reporting on it.

Party time! Larry, you and I actually taught Hobbit something!!

Now, Hobbit, if only I can digest everything you're saying. I need to go back and study your link and what you're describing here about the boost converter to fully digest it all. Regardless, you've helped solved a minor mystery that has been lingering (with me) for over a year. Thanks for following up and reporting on it.
Thanks Jim. I figured the law of averages had to eventually swing in our favor sometime during our life.:p:D But, in absolute fairness to Al, it did take him to explain the why/what we were seeing.

Hi All:

___And back to the original scheduled programming ;)

___Roy, the ScanGauge-II has a calibration offset that you build in at each fill unlike the OEM aFCD which is so far off to be intentionally deceptive to put it bluntly. After a top off to within a few ounces of empty (near empty tank) and an 816 mile drive, the positive offset was something like 8.5%. I will have to look it up in my review notes to give you an exact but the FCD read 72.8 mpg as shown above with the actual was just 66.998 mpg.

___About WS... The HSI can be used (sort of for maintaining a no-fuel flow WS vs. the Fuel flow WS. Consider the HSI from regen to Power of 100% and the EV threshold at 50%. No fuel WS occurs from about 0 to 30%. Any higher and the fuel squirt begins.

___I also have some pics of some very goofy transition stat4s (modes) but it will be in the Review Manuel and I are currently forming.

___Jud, of anyone in the thrread, you should have the most to say with some pics???

___I am scheduled to head up North with some of my relatives in my parents 2010 and will try and get some more pics and maybe a vid of the Prius-III’s WS action above 45 mph.

___On the highway, the Prius-III is about the poorest runner on a % basis over its EPA that we have ever driven. The -II was a tough SOB to crack but the -III is pathetic at just + 37.5% over EPA highway. When I look at the around town figures and subtract the customary 6 mpg, 100 + ACTUAL is going to be tough whereas the -II was 110 + mpg in a similar type drive. Best to put it this way... If you are going title to title against a TDI or HCH-II driver in terms of FE, you had better stay the hell off the highway or you will be riding a bike during your next point A to point B drive.

___All said, the Prius-III still offers a huge advantage over the TDI and HCH-II overall due to is around town capability but it lost some against the –II that those that are pushing high FE with their –II’s would be disappointed in the –III imho.

___Good Luck

___Wayne

Well, thanks y'all for posing the problem! It made for a very
entertaining headscratcher yesterday, but fortunately I had already
done a lot of the background on the boost converter or I would
have spent all day out there trying to figure this out instead
of cleaning the house like I need to. And it's way too hot to
be driving around in "experiment mode" in the daytime.
.
I still want to tnink there are many undiscovered mysteries
about the P-III, including mid-speed and highway. Remember, the
mid-speed deal in the II threw everyone for a looong time.
Hopefully my rundown will give people some basics to start
with, and it can all evolve from there.
.
_H*

unlike the OEM aFCD which is so far off to be intentionally deceptive to put it bluntly.That's a good point. My driving impression on the Gen III were based on FCD readings. I've been reading about HUGE deltas on the Gen III b/t FCD and actual. Puts a whole new light on my measurement of the Gen III.

11011011

I need a little more data for comparison ... can someone remind
me about the HSI behavior in the following scenario: acceleration
at a rate that holds instantaneous MPG right about equal with
speed in MPH as speed increases from about 10 to 50 MPH? Flat
ground, 60% nominal SOC so there's no battery influence, etc.
I just need to know where about to "park" the HSI to hold that
particular state of acceleration and get an idea of engine loading
in the process, i.e. is it a good target to shoot for. I'm finding
that it certainly is in the second-gen.
.
It would also be interesting if anyone's willing to remove their
intake snorkel plumbing upstream of the air box and see if not
having all that and the resonators in the loop makes any audible
intake noise difference, which could give additional hints as
to engine state...
.
_H*

For those of us that are less than well versed (read often confused) in the methods and the vernacular.... I'd appreciate it if someone could clarify a couple of questions.

1) When gliding in a III, is there a meaningful difference between manually shifting into neutral versus feathering the pedal to eliminate charging and avoiding the use of the electric motor as indicated by the HSI? (This latter method appears to be referred to as neutral by some?)

2) Is it definitively known that gliding in neutral (in either of the above ways) results in no "harm" whatsoever to the car?

Thanks much,

Robert

Hi All,

After 4 tanks my average per/tank mileage has been 59.1 mpg actual (max 61.9, min 57.5).

The cold weather is with us now, so it wont be till next summer before I know how good this car is. I expect a bump at the first oil change. I always had a bump up after an oil change in the 2006.

Oh, BTW, if you do not read Prius Chat, my 2006 was totalled by a Chevy Suburban which was poorly/stupidly driven, in combination with a poorly driven Camry in front of me, in combination with an incompetent construction crew cones placement, in combination with a state patrol that did not enforce the traffic zone speed limits around a blind curve.

Anyway, understand all the HID stuff, I think, but am still not satisfied with the mileage. Use of the HID resulted in a 4.5 mpg bump between the first and second tanks, in similar weather conditions. Until the tires are broken in , and the break-in oil is changed out, I really wont know what mileage this car gets. I was in the high 60's with 2006, and pretty much above 60 mpg above freezeing. But this car is somewhat short of this.

I have noticed, anectodotally, that the downhill warp-stealth glides (above 45 mph) of this car are somewhat worse than the 2006. Even though the N glide at lower speeds are right on, if not better. I have had the alignment checked, and its very close, with just a minor right rear caster issue (multiple measurements result in just out of spec, or just in spec).

At this time I believe the aerodynamic drag of the 2010 is somewhat higher than the 2006. Most likely this is because of a larger cross-section area. Although, the more non-square cross section of the 2010 might be part of the issue, resulting in more turbulent reattachement of side-body flow. And the tires are wider too.

Anybody with a telephoto lens, and digital camera want to do a cross-section picture of the two cars? The method is to get like 60 yards away from the car, then telephoto in to fill the frame with the car from dead on, then integrate the area in a computer. By having a large distance between the car and the camera, the perspective error is minimized.

Hi Donee:

The Third gen when pushed is not as efficient as the second generation under either an all-highway drive or all-out competitive level P&G by a long shot unfortunately.

That said, the third gen does feel a bit more comfortable and you will be blasting through 60 with no problem in very short order and even through the winter months. Do not give up!

A few more to read…

What A Difference A Driver Makes… (http://www.cleanmpg.com/forums/showthread.php?t=36335)

2010 Prius-III P&G, SHM_and WS_FE techniques rehashed, defined and refined (http://www.cleanmpg.com/forums/showthread.php?t=25579)

Good Luck

Wayne

Hi Wayne,

Thanks for the encouragement. My last 2 tanks in the 2006 were 70.3 and 70.7 mpg. I was doing the best ever with that car. But, then again, that was in July. I was on the last day of a tank the day the car was totalled.

My 2006 with the BT Tech plate was more stable on the highway in cross winds. I think the larger wheel openings on the 2010 has something to do with that. The 2006 was also more comfortable to me. I hate that knee bumping center console, and they have a sharp corner on the arm rest on the other side that nails me right under the knee cap. As many know. I have had a bit of a crusade against the center console on Priuschat. It just does not make operational design sense.

If I would have had a month to get a new car, I probably would have got a 2009. But, the insurance company only gave me a week of rental car time. And the dealarships I went to just were not prepared with service histories on any of the used cars. Lombard Toyota had the largest selection of used Prii. Without service histories, I felt I needed to go with the new car.

I have tried SHM techniques with matching indicated mileage. But, as we know that is really 5% less. And now with the cold weather, its becoming more difficult. It seems like it might SHM better at a higher speed (53 to 55 ish) rather than the 51 to 53 I used to do in the 2006. But, I do not have enough experience to be sure. I have had a few times now when locked in at 54 mph, indicated was 85 mpg, versus the 75 mpg at 52 mph on my reference road section for SHM with the 2010. In the 2006, I would lock in at 75 mpg indicated/actual at 52 mph, and just hold that down the flat reference road section about 2 miles.

Like I said above, it does seem roll good as, or better than the 2006 at low speeds. Its either the extra weight, or better tires. I have the OEM Yokohomas on my car. Have you heard anything good about the Nokia eNTyre? I might get better tires next summer.

My second tank was during warm weather, and indicated was 65.2, with 61.9 mpg actual. The third tank was up near 69 indicated, till the weather and off-time (short trips) took it down. Wether has been cold, raining or both since.