Archives

I’m starting this thread because I’ve been thinking of updating the HCH-II article a bit, and msantos asked whether I might add the P&G technique. So I’d like to summarize my experiences with P&G so far, and I’d also like to hear how he and others use this technique in their HCH-II.

First I want to mention, the original article was supposed to be basic and not include any advanced techniques such as FAS or P&G. In other words, I wrote it for a new hybrid owner who needs to understand what their gauges are telling them enough so they can just get in the car, drive it normally, and still beat the EPA. I’ll return to this point later.

I’ve frankly not had much success with “classic” P&G -- meaning the way the Prius drivers do it and I also haven’t used FAS yet other than keying off heading into parking spaces and a few predictably long traffic lights. Most of my commute is on the freeway at speeds averaging 55mph, and AFAIK P&G works best between 25-45mph. and you want to stay out the pack as much as possible. The freeway I feel is too dangerous for me to FAS.

So I use P&G in a much looser sense. In the city, from stoplight to stoplight is one example, and that’s pretty self-explanatory. On the freeway I try and take advantage of the natural ebb and flow of traffic. I think I’ve mentioned before that I actually prefer those days with medium traffic congestion because the traffic behaves like a long spring – you speed up and slow down, speed up and slow down. Cars around me may go from 0 to 50mph over and over again (stop-and-go) but I try to stay in the 15 to 40mph range and never hopefully completely stop.

If I keep a good buffer in front of me, and use the brake lights that are half-to-one-mile ahead as my glide-to target, I can extend some very nice long glides. However the glide usually isn’t pure EV – I find it’s easier to go into EV w/assist initially, let it drop out naturally, and finish the rest with no assist, or even with the ifcd just under 100mpg. (If I tried to keep it “pure EV”, that might last only a few seconds.) Again, I don’t FAS on the glides. Also on the pulses I watch my rpms, but it’s difficult to avoid some assist. Not that I can’t do it, but road conditions seem to frequently frustrate it. So I’ve quit worrying about seeing assist on the pulse and just concentrate on keeping accels slow and controlled.

On days when the freeway is clear and there’s no “giant spring” effect then traffic behind me is pretty unforgiving of more than a 5mph speed drop, so my range feels severely restricted for decent P&G.

So I don’t even know if the technique I use above should even be called P&G. However it might be useful to others since it’s easy to do in typical freeway conditions and in that sense it might work within the original article. I’d want input from Wayne on that though. I’d rather not write a lousy version of P&G for the HCH-II just because “it works for me.”

But it sounds like msantos has found how to transfer P&G techniques from his Prius to his HCH-II very well, so I’m sure doing he’s doing it much more effectively than I am. But what I don’t know is, how much of this involves FAS and what are the roads and speed conditions he drives in. To reiterate, I’d rather not write up what I’m doing if there’s a better way out there, but I’m not sure if I have the environment to do it “better” in. And if the better way for the HCH-II is P&G with manual control, that writeup should probably be separate from the original article.

Hi Tarabell;

First off, I would like to say that I do not consider myself (even remotely) knowledgeable about the basic P&G technique let alone the possible variations of it.

But, I'll be the first to admit it produces good enough results for me to swear by it (as opposed to swearing at it). Now, also allow me to add an additional disclaimer: My city only driving conditions don't always allow for P&G. Maybe someone else would think otherwise if they saw my driving conditions but I prefer to only resort to this if I see it's safe and considerate to other drivers to do so.
Many times I prefer to let one or two cars pass me so that I end up with an empty rear-view mirror. And that is good.
Other times, I happen to be at the head of the pack and my first instinct is to accellerate briskly to my target pulse speed with the intent of gliding and pulsing as often as I am allowed... unless of course, the cars behind catch up to me on the first pulse therefore denying me the opportunity to bleed my speed in a glide.

Now for the technique.

Please note that I tried to excuse myself earlier so please feel free to correct me if I violated the principle and/or the terminology.
P&G'ing on a Prius or HCH-II is in my view, an experience of identicals. The only difference is the human interface and the feedback that each car offers. On both case it is all about foot control. The more precise we can be the better the results are.

In a nutshell, I identify the following phases:

1 - Set a target speed
2 - Choose a rate of acceleleration (surrounding traffic often influences this one)
3 - Accellerate to the target speed at the rate chosen
4 - Glide for as long as possible to a minimum glide speed; sometimes use EV to extend the glide even further, especially when the conditions are ideal.
6 - Reach minimum glide speed and restart at phase 3 again.

Typically I choose the speed limit for the road I am in, then I add 10 to 15 km/h (6-10 MPH) on top of the speed limit to give me the maximum speed at the end of a pulse.
My end of glide speed typically occurs at 10-20 km/h (6-12 mph) below the speed limit. It is even lower if there is no traffic behind me.

Then I pick a rate of acceleration. I prefer to look at the RPM and the iFCD as a common indicator but that depends on other factors as well such as driving/road conditions (Snow, Ice, Rain, wind, surface type, etc), really, anything that can affect the rate of accelleration.
NOTE: In conditions with too much snow or rain the P&G is too much of a hassle since glides are dramatically reduced. On dry conditions such as clear warm asphalt or ice surfaces glides can really be long to make the whole technique bearable.

Once I start accelerating for the pulse I simply ignore the visual impact of what the gauges are telling me and focus on the end result instead. Quite often my objective is to accellerate at no more than 2500-3000 rpm to reach that target pulse speed.

Once I arrive to that target speed I lift my foot from the gas pedal just enough for the regen to almost engage. Sometimes I am wearing my elephant foot and I end-up seeing 2 or more regen bars and that is no good, but I try to cancel them by applying a hair of pressure back on the gas pedal ASAP.

My other objective is to also avoid seeing the opposite, which is the EV assist coming on. (OK, so I cheated. I can actually cancel the EV altogether because of a nasty mod we did last year. )
However, unlike the Prius I cannot add to the pack during a pulse, so I need to be more judicious about the use of EV. The only time I choose to use EV is when I can dramatically extend the glide and I have a good SoC to make it worth it. Other than that, the battery charge is too precious to waste and instead I prefer to reserve it for the climate control operation of the fan and AC when required.

With my foot lightly on the pedal, no regen bars, no ev assist bars I then let it glide. The iFCD is pegged at 0 liters/100K (100mpg) and I keep it there for as long as it takes to reach the minimum glide speed. I also keep an eye on my rear view mirror just in case I need to cancel the glide because of a fast approaching car on the right line or a car merging ahead into my lane.

Once I reach the minimum glide speed I restart the pulse again and I keep this "dance" going for as long as I can.

Now, the main reason I like this technique is not only because I like its results but instead it is one of the very few things I can do to keep my winter milleage from falling below the mid 30's. It is heartbreaking to see the mileage get progressively worse especially when the ICE no longer stops for the entire duration of the commute. Oh yes, the front grill is covered and the block heater is our best winter friend too ;).
Overall, I think I managed to keep my mileage up to some extent but I believe I'll do even better next winter now that this and other sequences are better engrained in my brain.

Also, I only use FAS a few times in the colder winter months. Other than that, I see no real purpose for it on the HCH-2 (comments?).


Anyway. That is all for now. Like I tried to say, it is a personal interpretation of P&G that works for me on my 06 HCH and was easily transposed from my Prius experience with no big functional differences beyond the ones we all too familiar with.

My veridict, is that P&G'ng on the HCH is just as easy (and difficult depending on the view) as doing it on a Prius... It almost looks built-in: courtesy of Honda's IMA Gen 4 design team. :)


Cheers;


MSantos

First off, I would like to say that I do not consider myself (even remotely) knowledgeable about the basic P&G technique let alone the possible variations of it.
Not true! and thanks for recapping the basic details for us again, which I didn’t do.

Now, also allow me to add an additional disclaimer: My city only driving conditions don't always allow for P&G. Maybe someone else would think otherwise if they saw my driving conditions but I prefer to only resort to this if I see it's safe and considerate to other drivers to do so.
OK I’m with you there, but my driving conditions are mostly freeway and I don’t feel that allows for P&G either. In the city I’ve got traffic signals every 3 blocks or so. You must have some nice open roads that support a disciplined P&G regimen.

Other times, I happen to be at the head of the pack and my first instinct is to accellerate briskly to my target pulse speed with the intent of gliding and pulsing as often as I am allowed... unless of course, the cars behind catch up to me on the first pulse therefore denying me the opportunity to bleed my speed in a glide.
This is exactly what happens to me on the freeway – cars behind me catch up quickly, even in the right lane. Only when cars ahead of me are slowing or already stopped, there’s much less pressure from behind and I have no problem gliding down as slowly as needed. That’s what I see as the prime benefit of the “giant spring” effect – I use the traffic flow to dictate what speed I should pulse to and how long I should glide.

Once I start accelerating for the pulse I simply ignore the visual impact of what the gauges are telling me and focus on the end result instead. Quite often my objective is to accellerate at no more than 2500-3000 rpm to reach that target pulse speed.
Same here – usually I’m going for about 60mph (max), but try to accelerate within 2000-2500 rpm.

Once I arrive to that target speed I lift my foot from the gas pedal just enough for the regen to almost engage. Sometimes I am wearing my elephant foot and I end-up seeing 2 or more regen bars and that is no good, but I try to cancel them by applying a hair of pressure back on the gas pedal ASAP.

My other objective is to also avoid seeing the opposite, which is the EV assist coming on. (OK, so I cheated. I can actually cancel the EV altogether because of a nasty mod we did last year. )
I forgot about this – you put in an EV button?

However, unlike the Prius I cannot add to the pack during a pulse, so I need to be more judicious about the use of EV. The only time I choose to use EV is when I can dramatically extend the glide and I have a good SoC to make it worth it. Other than that, the battery charge is too precious to waste and instead I prefer to reserve it for the climate control operation of the fan and AC when required.

With my foot lightly on the pedal, no regen bars, no ev assist bars I then let it glide. The iFCD is pegged at 0 liters/100K (100mpg) and I keep it there for as long as it takes to reach the minimum glide speed. I also keep an eye on my rear view mirror just in case I need to cancel the glide because of a fast approaching car on the right line or a car merging ahead into my lane.
Funny I find it difficult to hold pure ev with no bars showing long enough to get down to my bottom threshold. Mostly it seems to conk out too fast, before I want it to, and I have to chase after it with my foot again. Or I’ll hold it but a charge or a regen bar will randomly pop in and out till the end of the glide while the iFCD is pegged. Starting out with EV/assist does dramatically extend the glide further for me, but I try to keep it to just one bar when possible.

Also, I only use FAS a few times in the colder winter months. Other than that, I see no real purpose for it on the HCH-2 (comments?).
I think I would like to try using FAS on city streets, just to know how it’s done. Because the all-city trips are what really ruins my FE and I can think of some weekend mornings without cars around where it could be useful.

Anyway. That is all for now. Like I tried to say, it is a personal interpretation of P&G that works for me on my 06 HCH and was easily transposed from my Prius experience with no big functional differences beyond the ones we all too familiar with.

My veridict, is that P&G'ng on the HCH is just as easy (and difficult depending on the view) as doing it on a Prius... It almost looks built-in: courtesy of Honda's IMA Gen 4 design team. :)
Thanks for the excellent description. It seems like you have the opportunity to do it the "real" way on your roads. For me as they say, theory and practice are the same in theory -- but not in practice ;) . I’ve tried to do P&G this way many times on the freeway but end up frustrated. I can get in one or two cycles and then either I find myself trying to glide up a hill, or I’m pulsing into a stopped block of traffic, or the car behind me fills up my rearview mirror on the glide, but it always feels like I have 2 left feet and my timing is never right.

Anyone else have success with P&G on the freeway in your car? – Sledge? Rhwinger? Mr. Kite?

Thanks Tarabell;

I can say that now, I can hold a glide for a very long of time. During the winter is almost impossible because the ICE will kick back in before the glide is technically over. But since the good weather returned, I can hold this "no-ev" "no regen" mode for more than a couple of minutes (I never tried holding it longer). I know this for sure.


I forgot about this – you put in an EV button?



Actually, yes. It is not an EV button like the one we can get for our Prius. Instead, it does the opposite: It prevents EV from taking place for almost as long as we have it is depressed. I believe I described it at lenght at the request of a CleanMPG member (Ed, I think).

However, I don't think I am going to install it on the new 07 HCH when it finally arrives at the end of this month. On one hand my wife would probably not allow it (this is going to be her car for sure), on the other hand I am not totally sure it helps that much throughout the year, at least enough for it to make up the build cost.

By the way, since the good weather returned I've been having the best commute segments ever using P&G... I guess it is because the engine finally broke-in. I've been registering 3.6-3.9 liters/100km (60-65mpg) right after I stop the car in the parkade (3rd floor above ground level). My dirty secret is that I also leave home a little early to avoid the traffic rush hour madness... and yes, I continue to use my block heater. Guilty as charged. :o


Cheers;

MSantos

Hi Tarabell and MSantos:

___Great discussion!

___The trick with the HCH-II appears to be similar to the HCH-I or Insight wrt SoC control while running her through the cycle. Unless you have an “Assist defeat” switch (MSantos, someday you will have to do a thread on that one ;)), once your SoC is down to 3 bars (~ 6 of 20 in the Insight and HCH-I), you will only Force Charge on a pulse as the logic takes Assist out of the equation. If you can continue to use a full blown P&G via FAS, that is fine. It is the forced charge payback once your P&G period is completed where the problem lyes. My method of Gliding the HCH-II was to FAS as it is the most efficient given IMA spinning over the entire drivetrain (intake and exhaust valves closed or not) just to coast down or maintain speed takes one heck of a hit on the poor little pack. FAS to the lower target and begin a Pulse in the 2,200 RPM range, repeat. Of course I only had about 45 minutes in Terry’s HCH-II to come up with a rate and range for a maximum. 45 minutes was not nearly enough :( It appeared that a range of maybe 15 - 35 mph at an ~ 2,200 RPM rate for the local stuff worked well enough to get you into the 105 - 110 range if unmolested. Once I picked up the speed, the 100 + stuff fell apart fast. Given Tarabell’s article, it appears that a quasi light-footed DWL at ~ 35 mph steady state yielded nearly the same results? This is far different then a well setup Prius II in which a P&G between those ranges allows maybe 100 - 110 vs. the steady state where you would be lucky to see 80 mpg. I am speaking of a full blown FAS in the HCH-II for the Glide with that nagging Forced Charge hit waiting for you once you transition to a different set of driving conditions. The Prius simply smiles at you and says what would you like to do next :) I really do not know what to add other then to install and use an MSantos “Assist Defeat” and see what happens between 45 - 60 mph and back with a higher load Pulse (HCH-II that was SG-II equipped) and a true FAS for the Glide depending on traffic conditions? The Accord adds between 10 and 20% in a HS P&G (47 - 57 mph) vs. 50 mph steady state ops. The LS-MS stuff yields another 15% over a HS P&G. Because of what the Accord offers at the various ranges vs. steady state, I have always wondered if the smallish 1.3 in the HCH-II would provide a similar increase over a straight up steady state 50 mph or not?

http://www.cleanmpg.com/photos/data/504/103_0_mpg_19_5_miles.jpg

___Great thread and discussion about your respective HCH-II’s between two of the best I might add! I would like to see Ed and Bob comment as well given they have reported receiving some 80 - 90 + mpg segments themselves. I have no idea as to their methods and/or the conditions during the achievement of such however?

___And some OT discussion. Tarabell, did you receive anything of interest in the mail today ;)

___Good Luck

___Wayne

And some OT discussion. Tarabell, did you receive anything of interest in the mail today

No but you've got me nervously scanning the horizons now. ;)

I need a clarification about gliding the HCH-II. It was my understanding that the car shuts all of the valves and just lets the engine spin at low RPM during a glide, but I thought that this could be done in a no charge/no assist condition. That would be not quite as efficient as a pure glide but pretty close. But Wayne keeps mentioning the hit to the battery pack as if you can't get into that state. Is it really the case that you can't keep the battery out of the equation during a glide? Or is it common practice to add in a little assist on purpose in order to extend the range?

Everything about this sounds eerily similar to "warp stealth" in the Prius II above 41mph. I've seen 60,70, even 80mpg on my 5-minute bars travelling at speeds in the range of 45-50mph with lots of warp stealth P&G, but rarely anything pegged at 100mpg except maybe on a long down-hill.

That is a good question Tim.

My understanding of the system in terms of its behavior and also through my observations over the last year, is that you can indeed achieve the state of glide where you got no assist and no regen taking place all controlled by gas pedal pressure.
This is very, very similar to what we get on the Prius when the energy screen shows no arrows at all when gliding at less than 66km/h (42MPH). The only minor difference is that the HCH-II can be kicked into this mode at almost any speed (with varying results).

That is basically what I consider a sufficient glide pattern on the HCH-II.
Obviously, there may be some rules stipulating that a pure glide should have close to no resistive forces on the forward momentum of the vehicle as possible (engine off, etc). As far as I can tell, it remains a subject with much room for interpretation.

Slightly off-track:
From an engineering standpoint, the HCH-II does indeed close is valves by hydraulically moving its cam lobes into the "dis-engage" position and then the cam and pistons still continue to move with no fuel being consumed. Now, at first thought and had this been any engine, it would definitely be regarded as a terribly inneficient approach.
However, these resistive forces have been reduced significantly. Many of us believe that the HCH-II engine is perhaps the most friction free 4 cylinder production engine in the world simply because of the extreme engineering that went into its design and the use of many friction reducing techniques (some are quite exotic by most manufacturer's standards).
However most of us will agree that despite all these friction reducing tricks, it is still burdened by a "notion" of compromise especially when compared to the typical HSD system. Oh well, the discussion will go on at least.

Back on track:
I don't get the chance very often to take my Prius into higher speed duty, but as far as I can recall, the "Warp Stealth" effect (Energy screen, battery to wheels flow) can also be re-produced on the HCH-II in a very similar fashion. As per my experience it can be evoked at almost any speed above 20MPH to extend a glide if so desired.
Personally, I have made the choice to avoid using the battery to extend a glide on the HCH (simply because I am not as good and diligent as Wayne and many others here). The battery is too small in capacity to do such a thing unless the the SoC is good and the MPG potential returns are good enough to justify it.



Cheers;

MSantos

Hi Tim:

___The HCH-II’s pure Glide can be easily achieved. However, the energy losses to keep the drive train spinning no matter how low they have been designed too are detrimental to your total distance in Fuel Cut w/out Regen (EV-Glide) vs. a straight up FAS. You can glide while spinning the drive train with no pack energy being consumed but to reach the same distance as a FAS requires pack output and here in lye’s my apprehension wrt IMA-2’s capabilities.

___Consider this scenario. You are on a down slope and have reached a given terminal velocity using EV-Glide in the HCH-II. Under a FAS, your terminal will be higher because you are not spinning the ICE thus the glide itself goes further before having to use the pack under the HCH-II’s specific EV mode, reinitialize a pulse or transition back into steady state operation.

___MSantos, you and Tarabell have far more experience in the HCH-II then I ever will so take my discussion as one of limited experience. On my first test drive in an HCH-II, I lost SoC under EV so quickly and the payback was so painful to make me think Honda did not think this feature through. I can see where it would work to your advantage (think HS EV-Glide w/out power consumption) far beyond that of the Prius II’s std. glide or the pack sucking Warp-stealth but the energy consumed to spin over that ICE is seen vs. a FAS.

___Good Luck

___Wayne

Hi Tim:

___The HCH-II’s pure Glide can be easily achieved. However, the energy losses to keep the drive train spinning no matter how low they have been designed too are detrimental to your total distance in Fuel Cut w/out Regen (EV-Glide) vs. a straight up FAS. You can glide while spinning the drive train with no pack energy being consumed but to reach the same distance as a FAS requires pack output and here in lye’s my apprehension wrt IMA-2’s capabilities.


Hmm. Based on this it sounds like the real battle is not against the ICE friction as much as it is against Honda's battery management algorithm. See, the Prius will only let you Warp Stealth if the battery SoC is very healthy. If I step on the pedal a little too hard in WS and accidentally invoke battery power to propel the car (too subtle to feel most of the time) it will start kicking me out of WS in short order even before the pack indicates below nominal SoC. Getting WS back is nearly impossible once this has happened. The up side of this inconvenience is that the system never has to go out of its way to put energy back in the battery. The numbers are never as good as a sub-40mph P&G routine but still respectable if conditions are OK.

Short of FAS, my recommendtion would be for the HCH-II driver to step in and aggressively manage SoC by avoiding EV-assist at all costs during a glide. You may glide for a shorter distance as you trade momentum to overcome engine friction, but you should do much better than running down the battery to overcome engine friction and incurring all of those conversion losses when you run the ICE harder to charge the pack during a pulse. Your result on the highway should be just as good or probably better than a Prius II if you really can take the battery out of the P&G equation.

You can glide while spinning the drive train with no pack energy being consumed but to reach the same distance as a FAS requires pack output and here in lye’s my apprehension wrt IMA-2’s capabilities.


Wayne, I totally agree. I am curious though, about "quantifying" the loss in glide distance that is attributable to the spinning crankshaft when the HCH2 is in a "no-assist, no-regen" glide. Would that help?

Obviously, we can't use another non-hybrid Civic for inference (too many dynamic differences) so your reference to the use of FAS would be the basis for an alternate comparison baseline.

I'm thinking that this is a test worth doing (if it has not been done before). I probably should do it one of these weekends just for giggles. If the discrepancy is that large then maybe that will get me to consider the use of FAS more regularly.

Now, when you say FAS do you mean:

- Place the car in NEUTRAL (N).
- Powering OFF the engine with the key as the car enters the glide.
- Wait 5 seconds, then turn the electronics on without turning on the gas engine.
- Glide to the lowest glide speed, then turn gas engine on
- Switch transmission to D and restart pulse

Is this the routine? (just making sure)


Cheers;


MSantos

Hi Tim:

___It is a little of both. Running the HCH-II in EV is easy but you are not just spinning the wheels but dragging along the ICE at all speeds similar to the Prius II above 41 in Warp Stealth. The HCH-II is a little more efficient given the valve train movement forcing the intake and exhaust valves to close but very similar to Warp Stealth none-the-less. Dedication to managing SoC is exactly how to push IMA equipped hybrids in my experience. Unfortunately, they are so darn touchy it is almost impossible not to grab some assist under any accel. Eliminating Assist under EV-Glide is as easy as running a Prius II in a Glide below 41 as you slowly bleed off but it is the shortened distance before having to pulse back up vs. a FAS that kills you :(

___WRT the HCH-I having superior capabilities on the highway under EV-Glide, this is true since you are not forced to having an MG1 spin the ICE while dragging off the pack while you are bleeding off speed. It is the parasitic drag of the entire drive train (even with the intake/exhaust valves closed for pumping loss reduction) going along for the ride that is the same old problem however. If only Honda could have clutched IMA to the other side of the transmission rather then bolting it to the Crankshaft and used a much smaller MG1 setup for actually spinning her over for each and every start. There is no sense in crying over spilled milk but Honda knows they have a problem with the way IMA is forced to pull the ICE along with the vehicle. I am not sure what there next hybrid solution will be to workaround this issue? As tight lipped as Honda is, who knows what that solution will be?

___MSantos, the FAS description is good except for the period of time you are running in a dead state. The HCH-I can be cycled as fast as you can turn the key. I am thinking way back to Terry’s HCH-II during HF2006 but I thought that too was a very short period between shut down and reboot as well. Maybe .5 seconds at most so as to bring up your ABS and Air bags as well as the electronics so as to record distance traveled and your actual FE while under a FAS.

___Good Luck

___Wayne

... The HCH-I can be cycled as fast as you can turn the key. I am thinking way back to Terry’s HCH-II during HF2006 but I thought that too was a very short period between shut down and reboot as well. Maybe .5 seconds at most so as to bring up your ABS and Air bags as well as the electronics so as to record distance traveled and your actual FE while under a FAS.



Thanks Wayne.

I know for a fact that my HCH-II cannot be cycled that quickly. The reason why I mentioned 5 seconds is because anything less than 2-3 seconds will always restart the ICE. I have to wait just a tad longer which is one of the reasons why FAS has not been a "first love" thing for me.

Cheers;

MSantos

Unfortunately, they are so darn touchy it is almost impossible not to grab some assist under any accel. Eliminating Assist under EV-Glide is as easy as running a Prius II in a Glide below 41 as you slowly bleed off but it is the shortened distance before having to pulse back up vs. a FAS that kills you :(


It's exactly those 2 things that frustrate my efforts the most.

Here's my two cents, but msantos and Wayne are already talking over my head?

Most of my commute is on secondary roads now where the 5 AM traffic is light supporting what I call P & G. Like Tarabel, I don’t know what Prius drivers do, but I try to avoid interstates if possible because of interference with/from other traffic and reduced P & G speed ranges. Using the secondary roads with lower speeds adds 10-15 minutes to the commute, but seems to increase FE quite a bit. Afternoon traffic is a bit more crowded, interfering a bit with P & G, but the warmer temps must help make up for it as morning/afternoon FE results are usually pretty similar.

So a P & G for me is simply to accelerate to target speed as gently as possible, then back off the gas as much as possible without the regen bars coming on and glide as far as possible. Frequently I will incrementally accelerate to and “test” for target speed. A little blip of gas, back off and try to sense by the seat of the pants what the car is telling me. If I sense the glide is decaying off pretty quick, then I lower the target speed. Use the “Game Gage” as they say. Probably can’t do this with a semi on your 6, but early in the morning – hey I got my butt out of bed at 4 AM to be here and play. ;-) I just kind of pulse/test/glide repeatedly while driving the commute because wind, temp changes, terrain or whatever will seem to change the target speed.



Around here you can get away with P & G speed ranges on the interstate a few mph above the speed limit to 5 or so below. Keep a big gap in front, but not many instances of “giant springs”? I like that one Tarabel. :-)

Paying attention to the feel of the car, you can use physical/auditory cues to sense what is going on, even if you don’t/can’t see the assist or regen bars while trying to visually maintain situational awareness. On longer glides I try to keep one eye on them though just to try to stay out of the pack. Stupid question: After pulsing and backing off on the gas, there is like this “sweet spot” where the car is gliding, the engine is smooth as silk, (valves closed I’d guess), the speed is slowly bleeding off, but no assist bars are visible. Is there a minute amount of power going to the assist motor, below the threshold of detection by the display? Is this considered EV glide, or only when the assist bars come on? The reason I ask, with the warmer temps of late, I’ve twice been hit with a surprise forced charge. Surprise forced charge because it seemed like at one minute, the Soc was just over half and then the next thing I know there are two bars left on the Soc and the engine kicks in rather briskly to support the charge. Am I bleeding the pack w/o seeing it?

I’d like to pick up on the FAS technique, but so far I haven’t seen 103 mpg over any appreciable distance. Maybe I’m doing it wrong. That and watching the nav system reboot every time I key off makes me nervous?

Wayne, with mid 40 to low 30 mph P & G ranges, the HCH II gives me 80 -110 mpg in unmolested traffic on a particular 1 mile segment of my commute in moderate temps. Two weeks ago had a 86.5 mpg / 4 mi segment, P & G using hi 30 to hi 20 mph range, temps in the upper 60’s/low 70’s (engine warm on start, but not up to NOT), but not sure how much came out of the pack.

On the way home, freeway traffic around here usually allows low 60 to mid 50 mph P & G range for my first 10 mile segment, followed by a 45 mph to upper 30 mph, 20 mile segment. The trip mpg indicator is usually registering mid to upper 50 mpgs when I bail off the freeway. 10 more miles of mid 40 to upper 30 mph P & G frequently produce mid to upper 60 mpg results for the 31 mile segment above 60 degrees.

The best overall segment I’ve seen was 73 mpg over a 63 mile trip using 45 to 35 mph P & G.

As our mentor, Wayne, requested, here is my 2 cents.

I must start by congratulating those who participated in this excellent thread so far— it is so refreshing to hear from the experts and in such a humble way. I have only one item to add as it might relate to P&G techniques on the HCH-2. It has to do with the excellent engineering of the ICE. Please correct me if any of this information is not accurate.

Besides the cylinder deactivation mode, another small, yet very interesting, innovation that can be found under the hood is the use of eight spark plugs. These spark plugs then have two modes of operation. Sometimes they will fire one after the other, with the plug situated near the intake valve firing first and the exhaust plug firing later (I think of this as “lean burn”). This offset firing order allows for a more complete combustion of fuel in the cylinder, giving the car greater efficiency and cleaner emissions. Other times, the plugs can also fire simultaneously for a greater power boost. BTW, I think all ICE should have this design.

For me, I seem to see the greatest impact on mpg in all types of driving when I try to stay in “lean burn”. I do this by perhaps a different type of P&G or foot shifting(???). I quickly push my foot on the gas so I see a few white bars and then quickly let my foot all the way off so I see only a few green bars and then return my foot to the pedal so I do not see any bars at all. In most cases this puts the car in this mode. I must, however, add the variable of wind direction which in our experiences significantly impacts this technique. It is our 2 to 3 hour trips driving under 65 mph with a tail wind of 5 mph or more (with few stops) in rural like driving that we post our highest MPG. For example, we might gradually accelerate to 60 mph, activate “lean burn” mode then maintain “lean burn” and glide until approximately 50 mph. (if traffic permits) and then repeat. Sometimes the car does slip into cylinder deactivation mode on declines etc.

Well, anyway, I hope this is some help to this high level discussion. We have now had Opec Nightmare for 1 year and we have much more to learn.

...It has to do with the excellent engineering of the ICE.

You know... I am compelled to agree (without veering off-topic too much) that there's a lot of nifty enginnering in the HCH-II ICE.
Perhaps we should start another thread discussing the actual details, because since last year our faculty has named the HCH-II's engine as first "trully hybrid" gas engine in the world. We're actually looking for ways to debunk that but so far we have not heard of any counter arguments. We are actually trying to submit this as a potential thesis topic...


I do this by perhaps a different type of P&G or foot shifting(???).


Isn't this really close to the technique Tarabell illustrated in her article (Gary's "fake shifting")?

Cheers;


MSantos

Perhaps another mechanical factor that I failed to mention is the CVT that may enhance this “P&G” technique. This helps to move the belt to the highest possible gear ratio. Anyway, it seems to work well for us.

As our mentor, Wayne, requested, here is my 2 cents.

For me, I seem to see the greatest impact on mpg in all types of driving when I try to stay in “lean burn”. I do this by perhaps a different type of P&G or foot shifting(???). I quickly push my foot on the gas so I see a few white bars and then quickly let my foot all the way off so I see only a few green bars and then return my foot to the pedal so I do not see any bars at all. In most cases this puts the car in this mode. I must, however, add the variable of wind direction which in our experiences significantly impacts this technique. It is our 2 to 3 hour trips driving under 65 mph with a tail wind of 5 mph or more (with few stops) in rural like driving that we post our highest MPG. For example, we might gradually accelerate to 60 mph, activate “lean burn” mode then maintain “lean burn” and glide until approximately 50 mph. (if traffic permits) and then repeat. Sometimes the car does slip into cylinder deactivation mode on declines etc.

Well, anyway, I hope this is some help to this high level discussion. We have now had Opec Nightmare for 1 year and we have much more to learn.