HCH2 on electric only

Discussion in 'Fuel Economy' started by baltobrewer, Jun 8, 2006.

  1. baltobrewer

    baltobrewer New Member

    I've heard many auto magazines complain that the HCH2 can't run on electric only. While it can't self-motivate from a start with just electric like the Prius, it can close the valves at highway speeds and use the electric only assist going downhill. I use this feature all the time, to very good effect. The key is to find a gentle downhill and at the top, back out of the throttle once you're up to 60 mph or so, and then veeeeeery gently ease back into it to dissipate the green charge bars and continue tipping in ever so slightly until you get 3 or so white assist bars. The valves are closed, and the engine is running off of electric at this point. I have run this way for a mile or more at a time.


    You have to very slowly edge back into the throttle or else the valves will open and the fuel delivery will start, so a steady foot is mandatory. But, if you can do this you can force the car to use the battery only at cruise speed on a downhill. With cruise control, the throttle is too flighty to hold the engine on electric for any length of time....

    Also, I've noticed that when you let off the throttle, the regen kicks in very strongly, with the green bars maxing out. This obvoiusly tends to slow the car. If you don't really need the charge, you can tip into the throttle just enough to erase the green charge bars, and let the car naturally drift. If you happen to be going downhill you can see how good the aerodynamics actually are. The car drops like a stone.

    What a car!!!!!

  2. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Jay:

    ___Welcome to CleanMPG!

    ___Not only can you run EV/Glide from ultra high speeds, Tarabell has discovered a new trick or two with regards to the HCH-II’s EV/Glide mode to improve FE at very low speeds as well ;)

    ___I am glad you are enjoying your car as she’s a beut if I do say so myself!

    ___Good Luck

  3. Green&Blue

    Green&Blue Well-Known Member

    Wayne - what thread / post was that - I didn't see it offhand...or was it in chat ?

    A misnomer to the thread title, but a "see if you can try this" for the HCH2 pilots - bouncing the iMPG gauge. Or, another way of thinking - the iMPG 'recal' :p

    This works best at 30-42mph or so - right at the peak efficiency / gearing range, and needless to say, on level ground starting out. It could possibly be done on a descent, but if the descent is steep enough, just go for the no-assist fuel cut.

    Get to your cruising speed, and into your lean-burn (iMPG at 80 or better)
    Ease up on the pedal just a bit, until you're in the 90-95+ range. Now ease up a tiny bit more - it's tricky not to shut the valves, but it can be done.

    You'll see the iMPG gauge hit 100 for a second or two, and then...the bars disappear gradually - as if you were stopped. But you're not. Instead, you're at a steady rate of speed. You'll see the iMPG at zero-5mpg for up to 10sec, and then it starts climbing again...little by little, sometimes regressing a bit before climbing some more...and then it maxes out / holds the 100mpg. You'll note that you're maintaining speed, not dropping as you would be in EV-mode, and there are NO assist / regen bars. You also don't have the tell-tale 'thunk' of the shut-valve mode engaging / disengaging.

    This can be maintained for a minute or more - it's usually external (to the car) forces or a twitch of my foot that cause me to drop out of the mode. But except for the narrow speed range, and the sensitivity at which it drops into / out of the mode, I can invoke it pretty regularly when conditions warrant.

    When I do, I hate to see the car accidentally /eventually kick into EV mode (by being overly light on the pedal), because coming out of EV-mode, the iFCD drops back into the 50-65mpg range, and I have to start the process all over again to get back into lean-burn. A prime reason why I don't deliberately engage EV-mode often on steady-state cruise.

    As to 'why' - the only thing I can figure is that it's recalibrating for a 'super-lean-burn' mode. The air/fuel ratio for the LDA2 engine is in the neighborhood of 22:1, if I'm not mistaken (the 1st-gen HCH's LDA1 ratio is calibrated exactly one notch leaner)
  4. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Mark:

    ___Very interesting trick! How is your real world FE during the “iFCD bounce” for lack of a better term?

    ___Tarabell posted an interesting tidbit in chat the other day. She is working on a write up for it now in fact.

    ___On an OT note, I have a spare ticket to the Milwaukee Hybrid Group - annual Miller Park Brewers Baseball Game - Group Meet this weekend if you were interested? Courtesy of CleanMPG of course ;) Channel 12 News will have a morning show segment on the event/gathering and Bradlee is looking for 4 more hybrid knowledgeable bodies interested in on camera interviews? Let me know if you would like to attend either the Morning News Show earlier Sunday morning or the ball game on Sunday afternoon ASAP.

    ___Good Luck

  5. Green&Blue

    Green&Blue Well-Known Member

    You know, I forgot to mention - I reset the averaging display the other day to check on the iFCD during the 'bounce'... and it registered 106 or 108mpg during that time. So I think the iFCD display is 'accurate' during the event. As an aside, when I drive a long distance at a steady iFCD rate, I see the averaging display in sync with what the iFCD reported.

    The trick is holding / sustaining it for a decent amount of time, and like the EV-mode, the opportunities to use it are limited (I'm sure you'd find a way around that, of course) ;)

    My Sunday morning is tied up, but I might be able to make the ballgame (and I'll be happy to pay for the ticket - that way, I can help contribute indirectly to the CleanMPG operating fund :D ). I'll PM you with my new cell #, as I now have that set up & running. Will be tied up tonight, but give me a call tomorrow if time allows ? And thanks!
  6. Katz6768

    Katz6768 Active Member

    Try the same thing in metric mode (L/100km). I find it a lot easier to read, the FE display shows one lighted square and you see the 3 or 4 bars of assist if you're pressing the gas lightly or no assist and no gas being used... like rolling in neutral. It makes more sense a display that shows that I am not using any gas, instead of the very high mpg.
  7. philmcneal

    philmcneal Has it been 10 years? Wow

    wow i love details like these! The hchII sounds like a natural hypermiler and people are beginning to see its potenial, awesome!
  8. krousdb

    krousdb Defiant NX-74205

    I thought you said that the HCHII does NOT have lean burn. What gives?
  9. xcel

    xcel PZEV, there's nothing like it :) Staff Member

    Hi Dan:

    ___From everything I have read, it does not.

    ___Good Luck

  10. tbaleno

    tbaleno Well-Known Member

    Maybe its "not supposed to" but maybe Mark is finding a way to put it in that mode anyway ;)

    It will be interesting to see what develops from this.

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