Hi GoNavy:

___I haven’t yet read that the intake/exhaust will close on any 0 degree accelerator pedal angle but if so, Honda is thinking along the right lines just as they did with Fuel Cut. It is the spin over of the ICE and forced regen on any let off that they screwed up on. As you stated, the intake/exhaust closing up w/ the ICE spinning over and probably Regen forced into the mix, is not a coast but a type of engine breaking or simple regen. If you are going to perform a FAS in the 06 HCH and it works like a Fuel Cut mode, you don’t gain anything over the present HCH other then hopefully those valves stay closed as you drop to neutral so you do not have to use the key to take the ICE out. I bet the intake/exhaust valves open back up at a particular RPM so as to make sure she is not idle starved just as the Insight/HCH does today during Fuel Cut. As soon as it sees 1,100 RPM or less (this would happen very quickly in a simulated P&G or FAS), the valves open back up to provide idle and there goes the fuel savings of a full blown non-automatic P&G or straight up FAS. We shall see soon enough …

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

So, am I to understand that if I simply put the tranny in neutral and coast I'm not getting any benefit, or is it to say that i'm not getting as much as if I turned it off completely? Also, when you coast is it the goal to not recharge the battery (hence switching to neutral)? In that case, each pulse uses up charge, then the coasting doesn't replenish it, so eventually the engine has to charge while pulsing. Is this the intended situation with PnG?

 

If you pulse correctly you shouldn't be using any battery.

 

Hi Zimbop:

___In regards to a neutral coast, not at all but you are not gaining what you could with the ICE shutdown by a large margin.

___Here is an experiment for you. The next time you think about leaving your driveway from cold, reset a trip meter. Drive to the nearest stop sign and you will probably be in the 25 - 70 mpg range depending on your driving habits. Since the Coolant has not yet reached its minimum temp threshold to allow an AS, your HCH will sit and idle at the stop sign or light. Watch your FE drop .3/.4 mpg every few 10’s of seconds. The same thing is happening at speed in neutral as well vs. no fuel use at all … there is a savings in a neutral ICE on coast but it is not nearly as dramatic as ICE off.

___The goal as Tom mentioned is to have a high SoC in the first place. You do not use Assist in any Pulse if at all possible! Let your normal driving take care of the SoC, not decelerations using Regen unless it’s mandatory to grab the binders because of a light that changed or a traffic condition requiring brakes. In that circumstance, grab all the regen you want before a stop but under most instances, you should hardly use your brakes at all. Regen is wasting more of your kinetic energy then you are receiving in potential via SoC increase despite what the latest Hybrid commercials are promoting …

___Lastly, we are talking about a hack to make the HCH/Insight run in a mode that the Prius can and does run in automatically with a little footwork. Krousdb’s perfection of the technique in is Prius II allows some really stunning FE but it is really not an IMA based Honda’s forte’.

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

So than accelleration is important for png - you have to go easy enough to not use any assist? I'm not sure I can do that here with the hills and such - seems I have to use some assist to get up it unless I want a flattened rear end.

I have noticed the mpg jump up a notch or two when i glide down a long slope so I will continue doing that for sure. As for the png as a regularity on flats and elsewhere, I don't think I'll do it much. I'm on the freeway most of the time, speed limit here is 75. Between the folks limping junkers to mexico and the ricers and powerstrokes with horse trailers blazing around, there's large and small vehicles going anywhere from 40 to 90. Plus, new mexico has twice the national average of dwi's, and that's a scary mix. I don't think I want to add too much more to that equation, its already pretty unbalanced. I'll just get my 43 mpg with the cruise on and be glad the HCH has side airbags. :-)

 

P&G isn't really something that's efficient at high speed because wind resistance will make the glide portion so short that the pulse portion will need to be done too often to realize any benefit, besides the obvious nature of high speed driving where keeping with the flow of traffic is the safer thing to do. It's more suited to lower speeds where you can coast for much longer (3x) than you pulse.

But as has been mentioned it's not necessarily a good idea to use p&g in an HCH as you would in a HSD equipped vehicle because of the design.

 

Do you know of anyone actively working on this or what progress has been made? It seems like it _shouldn't_ be difficult to put auto-stop under manual control, on the other hand there are probably plenty of safety mechanisms in the way.