ICE management in HCH-II vs. Prius II?

[brick]

One of the main attractions (in my eyes, anyway) of a Prius or HCH is the ability to P&G with relatively low driver effort needed to kill and re-light the ICE. Question is, how tough is it to master that technique in each vehicle? On the HCH-II it appears that the instrumentation makes it pretty clear whether or not you've succeeded: tap the throttle and look for no regen/no assist. Right? Is it that simple in the Prius? I am to understand that you want to modulate the throttle in such a way that you get "no arrows" on the MFD (nothing from the battery, nothing from the ICE, nothing going to the battery either). Does that display respond quickly enough to be used as a real tool? Or are their other seat-of-the-pants indicators for a pilot to look for?

Nobody panic, the Accord can't go anywhere until I've brought her up past Expert status and beyond . I'm just curious since I've never sat in either, much less driven one.

[TonyPSchaefer]

I'll take a crack at this one. I've been driving Priapus for two years. I think that I've got a pretty good feel for the Prius and this tank is shaping up to end somewhere near 62 MPG - a personal best.

There are all these various stages of operations that some Prius drivers talk about. They represent the various modes of power-split and engine rev and other things that I simply choose to not memorize. I’m blonde, have a short memory, and confuse very easily. What was I talking about? Oh yeah.

When cruising along at less than 40MPH, it is not terribly difficult to let up on the pedal and engage “stealth” mode when all the power is coming from the battery. It’s easier if you let up enough to coast and then engage the stealth than it is to go straight from all-engine to stealth.

But there’s this point at which the Prius seems to be “confused.” It’s not sure if you’re pressing on the pedal hard enough go into stealth or if you are letting up enough to engage regenerative coasting. When it can’t decide, it “lets loose” and you can “glide” without burning gas or consuming battery. It’s what you called “no arrows.” If you’ve ever felt the drag of the regenerative coasting, you know that it feels as though you’re driving through standing water. I mean, it’s a real drag. (Drag! Get it?) Anyway, when you engage the gliding, that drag goes away and it actually feels as though you are accelerating: my wife got upset with me once as we approached a stoplight and I pressed on the pedal enough to disengage the regen and go into glide; she thought I was accelerating.

Now for the feedback portion:
On the MFD, you can see exactly what you’re doing. Granted, it’s a three-second delay, but enough to let you know. When you are stealthing, you can see the arrows coming exclusively from the battery and running to the wheels via the electric motor. Physically, you would probably not notice a difference. The car is moving and you can feel the car propelling itself. In fact, sometimes, Priapus slips into and out of stealth for one reason or another – usually because I’m not paying attention – and I don’t notice.
As for gliding, I mentioned that you can feel the car let go. Now that’s a real sensation. You feel that one and then you see the MFD update with the “no arrows” indication.

There’s one thing that I’ve noticed: when I’m cruising in Priapus and maintaining a constant speed, it doesn’t seem to feel as though I’m moving as fast as I am. I can’t really explain that one. Maybe it’s that I’m not pinned to the seat or that the engine isn’t running hard or loud. Sometimes I’m tempted to press harder on the pedal in order to make up for the speed I’ve dropped only to look at the speedometer and realize that I haven’t slowed down at all. Weird.

Well, I hope that helped a little. I know it’s not techie and it’s all based on my personal experience without any references to complicated mathematics.

[xcel]

Hi Tim:

___Another long, kind of worthless, and OT post by me … I hope you can stand it

___Tony has got it so right on with regards to the Prius II that you will have no problem learning to transition into and out of the Prius II EV/Glide/Pulse modes in literally a matter of an hour or so of practice even from an absolute newbie because you already have a very good understanding of what we are all trying to achieve. I am not speaking of a brand new driver in a brand new Prius II right off the lot that is not setup in the least but a reasonably astute hypermiler taking one out with some miles that was decently setup and that you can experiment with for more then just a test drive …

___The HCH-II is a bit tougher nut to crack in my experience and really only because I have so little time behind the wheels of Terry’s and the 20 minute test drive last winter … For one, the HCH-II’s iFCD is buffered heavily so you do not see how you are entering into and out of the different modes as fast as you feel them in your behind or through the wheel. This is where the HCH-II’s smoothness is a detriment in that it can be very hard to discern whether the ICE is still powered up or you have actually entered into its EV-Glide modes of operation. The Charge/Assist meters are dead on in this regard (not really buffered) so you have an immediate feedback from them to know what mode you have entered … I will say this however. Trying to P&G an HCH-II using the built in EV-Glide modes is frustrating because the transitions are not nearly fast enough by comparison to the Prius II. On the other hand, achieving a 1 mile + long FAS at 65 + mph in an HCH-II is as easy as it is in your Accord. The only thing you can do with a Prius II is go into warp-stealth and you are chewing away precious energy you would have preferred to use for much slower EV propulsion when and where it can make a difference.

___I am wondering why you are asking? One thing I am trying to do is to steer the best non-hybrid Hypermiler’s (you are included in this description) to transition into a hybrid as their next automobile with the understanding that you would choose the proper hybrid for the type of commute you are under the constraint of. Heavy stop and go with the ability to DWB and P&G within its constraints leads you to the Prius II. Slow suburban type travel with Rabbit timing allow you to take advantage of the HCH-II and the Prius II. Slower speed highway’s the HCH-II simply comes alive with the ability to move into and out of EV-Glide and a normal 75 - 80 + mpg cruise. It is simply amazing to watch the 4 door HCH-II’s iFCD simply camp at 75 - 80 + along with moving into EV-Glide on long down hills and the aFCD continually climbs like you would not believe.

___Now that I know what an Insight is worth in a LS P&G, if you were happened to live in a very rural community with paved country roads and 10 + mile commute to work, there is absolutely nothing on the planet that will stop you from 150 + mpg segments all summer long other then traffic and signs that you may have to traverse. I am talking country roads with little to no traffic other then waving by the occasional 45 + mph speeder or other such non-sense. I thought 100 – 110 on the Interstates at a stupidly slow 45 - 52 mph travel speed was becoming easy when I let her go but if you can drop her below down to 40 mph of below w/ lean burn evoked, you will see 115 + mpg segments again and again and again at steady state cruise! Just wait and see what Randall does once he starts P&G’ing for all its worth on his commute. Burning 10 gallons of fuel once every 8 weeks over 1,500 + miles at 150 + will be something of an eye opener to everyone but one the Insight is completely capable of IF you live in an area where this driving technique alone can be sustained …

___Finally, I am considering such a location for my next home as my wife’s job location is still in flux and even though it will not be in the San Francisco area as was the case 3 months ago, I do not really care where it is as long as I can find a home on that country type road with a commute to wherever where my abilities can be completely let loose and sustained for tens of miles. I just absolutely hate going to gas station is the bottom line

___Good Luck

___Wayne

[brick]

Originally Posted by xcel

Hi Tim:

___Another long, kind of worthless, and OT post by me … I hope you can stand it

Worthless? Far from it! This is exactly the kind of information I'm looking for, and the more the better!

Originally Posted by xcel

___I am wondering why you are asking? One thing I am trying to do is to steer the best non-hybrid Hypermiler’s (you are included in this description) to transition into a hybrid as their next automobile with the understanding that you would choose the proper hybrid for the type of commute you are under the constraint of.

I'm flattered, and possibly busted! I keep saying I'm not about to trade the Accord, which is true...for the time being. However I have some long-range plans that require long-range research . It's really tough not to look down the road at the possibilities given what I've seen and learned over the last several months.

Choosing is going to be tough, but there's no telling what my paraticular situation will look like when the time comes. We're talking about a mininum of a year or two out and that's plenty of time for circumstances to change...and fuel prices to get even more out of hand.

[brick]

Man...the more I read about these cars the harder it is to pick a clear "winner" when it comes to hypermiling capability. I just finished reading up on Warp Stealth, which sounds quite comparable to the HCH's EV-glide capability. Though a full-on FAS in the HCH would be preferable, these two throttle-only modes sound roughly equivalent when you consider what's spinning and how the energy is flowing. Sounds to me like the big difference is that the Civic's ICE-only mode allows for the killer steady-state numbers whereas the Prius is always stuck with some conversion losses at highway speeds while MG I and MGII exchange power to maintain the proper gear ratio...unless I misunderstand what's going on?

And the low speed advantage of the Prius comes from the fact that you're only spinning one of those MG's below 40mph, which produces less drag than spinning the whole ICE like the Civic has to, or the Prius does during WS. Pretty much?

I think I understand why the car really needs to be tailored to the commute in this case.

[xcel]

Hi Tim:

___The really neat thing is that you do not have to understand the cars down to their last electric pathway (ala CAN-View watching the multiplexed signals into and out of the MG’s in the Prius II or MIMA with its reverse engineered method of controlling charge and assist rates), you only need to learn to drive them for all their worth. I am a slower driver then most other then maintaining momentum through and around obstacles, but the HCH-I, II, and Prius II will simply floor you with their rather large bulk 2,700 - 3,000 #’s and what they can achieve while just driving them. It amazes me each and every time I have the opportunity to get behind the wind screen of one of these beauties because they are so far beyond the subcompacts, compacts, and mid-size vehicles in terms of capability it isn’t even close to being a fair fight.

___In terms of picking a clear winner, that is a very tough call. I can say that if you are stuck in the worst deep inner city - 20 mile type nightmare you can imagine (downtown NY city, Chicago, San Francisco …), the FEH and Prius II are the two toughest animals on the block. A little country, city arterial, or suburban type driving and the Prius II really shines with the HCH-II just starting to sprout its wings. A lower speed but less congested suburban arterial or slower speed highway and the HCH-II comes alive all on its own with the Prius still holding tough. Even when you start getting into the 55 - 65 mph range, the Prius II/HCH-II are still holding their own against all others (killing them other then the diesels actually) but the really amazing numbers are fast fading into the sunset and you come back to earth with the 50 - 60 mpg type ratings they are worth at speed when well setup …

___The Honda Insight? Except for a deep inner city driving scenario, nothing is going to touch that animal as it is an absolutely ferocious – caged – and hideous beast that can be called upon with a minutes notice to kill everything in its path when let loose into the wild at 70 mph and below

___Good Luck

___Wayne

[TonyPSchaefer]

Originally Posted by brick

Man...the more I read about these cars the harder it is to pick a clear "winner" when it comes to hypermiling capability.

Then just forego the whole hypermiling thing and look for functionality.

Hey Hondas, look at this!!

[xcel]

Hi Tony:

___Now you are not playing fair

___Good Luck

___Wayne

[brick]

Actually, I was talking my half-baked plan over with my girlfriend last night and that little detail came up. I miss my old station wagon, and the one thing I really don't like about my Accord is the fact that I just can't fit anything in it that's larger than, say, a duffel bag. I even got the GF to admit that she "doesn't hate them" despite always having made fun of me for wanting one.

Lord help me, I calculated the payments yesterday after work. Must...regain....control....

Whew...alright, I'm back to my senses now.

[xcel]

Hi Tim:

___Think pleasant thoughts like those below

Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!
Prius II Tax Credit - $3,150 || HCH-II Tax Credit - $2,100 || Friend purchases a brand new, 2006 Toyota Prius II for $18,155 + tax!

___This should help keep you from sleeping soundly tonight while your head is spinning around like the girl from the exorcist doing the payment math over and over and over and over ... Unlike Tony P., Terry H., and Dennis G., who will be sleeping as soundly as a baby since they already own these 2 evil cars

___Have I told you that NAVI in either car is a kick @$$ option too

___Good Luck

___Wayne