Hi NASAgineer:
___From your recent posts, I would say you are the most experienced HCH-II P&G’er on the planet

___Keep up the excellent documentation/presentation and keep on posting the results! Do not worry about holding a steady speed - EV mode at 50 + mph as you really want to bleed off to avoid pack use but it will be interesting to hear how fast your SoC falls at various steady speeds while in pure EV. Your posted results at 50 mph are saying quite a bit as a 20 HP MGSet should be able to hold the HCH-II at 50 mph indefinitely as long as pack voltage can be maintained. This is where the spinning mechanicals of the HCH-II are probably killing her capabilities as expected That 20 HP may be at low RPM’s and not high so it might be powering as expected once I think about it?

___My continuing interest in your HCH-II’s capabilities …

1. FE in a lengthy distance HS P&G between a 45 and 65 mph range (multiple cycles) if possible without SoC falling away below 4 bars to eliminate possibility of EV/Glide at high speed. Reset the Trip B from a stop and see what she’s worth … I am guessing ~ 100 mpg but am not sure about the pack bleed down to < 4 bars and then ICE-On in the Glide as you described earlier?

2. FE in a lengthy distance straight up P&G between a 30 and 45 mph range (multiple cycles) if possible without SoC falling away below 4 bars to eliminate possibility of EV/Glide in a slow speed cycle. I am guessing you will see 110 + mpg?

3. Steady cruise FE (ICE-On) at 53 mph. DWL over smaller undulations if need be. I am hoping you will see ~ 70 mpg but that is really stretching it for a brand new HCH-I or II that is not completely setup and may be impossible w/out leanburn? This should tell you what the atkinsonized intake and slow speed/low load cam(s) can do for her?

4. Distance allowed while in EV mode at 10, 20, and 30 mph and how fast the SoC falls from 8 to 4 bars and then ICE start at these slower city commute like speeds.

___All after pressing up those tires to at least 50 #’s! If you cannot find any 0W-20 near your home for its first oil change, I will send you 3 quarts of my fast diminishing stock

___Good Luck and Thank You

___Wayne R. Gerdes

 

The trick there is finding a place to do it! I keep running into lights, traffic, or hills that keep from from completing a single cycle. Maybe next weekend I can take a road trip out of the bay area and find some open space.

If I do the pulse with no assist (as you describe), why would the SoC drop at all?

I was getting a sustained 60-65MPG (hard to tell, but I think it was 13-14 blocks on the instant MPG) at 48MPH for a stretch today. Is there any way to tell if it's in lean-burn?

I didn't do a full test of this, but based on how fast it was dropping, I'd say not more than a mile or two. When I find some open space, I'll do a better test.

Really? They are rated at 32PSI.

 

I don't think there is a lean-burn. Anyway how are you using your trip meters? I mean, I use Trip A for tank mileage and Trip B for whatever. Like if I want to see exactly what FE I'm getting during a highway stretch, I reset Trip B, let it run one mile to be sure, and that's my instantaneous FE. I basically end up resetting Trip B every 40-80 miles and that lets me see how my most recent driving is doing.

There's no point in using one for lifetime mileage IMO since you can easily record that yourself.

 

Boy- go away for a weekend and look at what I miss!

Sounds like Honda is approaching a 'properly' engineered consumer product- one that gets pretty close to optimum without requiring the operator to be a rocket scientist (or EE, or Nuke, or...)

Simply the fact that it more or less consumes ~zero fuel when one's foot is off the gas at any time at any speed is a QUANTUM change. In fact it sounds like its been nearly perfected for Joe-binary driver (binary as in foot on gas or foot on brake; never foot on nothing) since it appears that SOME gas pedal pressure is required to avoid coasting regen- Joe's foot is instinctively on one of the pedals even when coasting is possible, so just calibrate that DC bias out of the picture.

Methinks that although a dead ICE would be ideal for coast, practicality necessitates it to keep spinning- keeping Joe driver and his 50th-percentile buddies in mind. IIRC reading elsewhere in GH that its illegal to drive engine-off in some places? Engineering aside, keeping it spinning might get around legal issues, if "engine off" is defined in legal code somewhere.

The 'EV mode' sounds, from NASA's empirical evidence, to be doing exactly as intended- enable the slow-speed crawl through a parking lot, carpool dropoff, etc. It seems correct that it will not hold speed at 50mph, although that would be nice. The IMA+tiny pack as they exist just aren't meant for that- 20HP yes, but at what (drivetrain output) RPM and torque combination? Apparently not high enough for 50mph.

Two questions:
- At what speed does autostop engage (as in dead ICE, not just spinning with
valves shut) as you approach a stop?

- I may have missed this in the specs or this thread, but can you start from a dead stop in EV-only? It doesn't seem so- EV mode only works on the way down?

 

Nasagineer,

Thank you for telling us in non-acronym english, how you achieved 100 MPG. I'm getting my 06 HCH on 1.2.06 and can't wait to apply your findings.

In the brochure it says that in speeds under 35mph, with light throttle, that the gas engine's valves completely shut down and the electric motor takes over. (I'm typing off of memory, so my apologies if this isn't 100% correct.)

My takeaway is that with cruise control (same as light throttle?) set at below 35mph that the 06 HCH should be at 100 MPG.

Have you tried cruise control set at below 35mph?

 

Sealing the valves makes no sense.
If they are left open...now thats a different story...I would check the facts on that one. I could however be wrong. Won't be the first time. Or the last.

 

Be careful not to read more than was written, and get your expectations up...

He's not getting 100mpg for entire trips- that's the max readout of the instantaneous mpg display. If the engine is not burning gas, he is getting infinte mpg...for those short segments that the engine is off. Any car can do that. The instant mpg changes constantly as the engine's load changes- be very careful not to think that you will get 100mpg on a trip or over a full tank!

It is worthwhile to find out if cruise control under 35 will still allow electric-only, or if there is some sort of interlock that keeps the engine running with CC on. "Light throttle" means flat or downhill at steady speed- not accelerating, climbing a hill, pushing against a 30mph headwind, etc.

 

Makes perfect sense. You now have a more or less closed gas system- you are compressing as much air at any given time as you are expanding, and simply exchanging pressure, and volume among the cylinders. The restoring force from the air in the compressed cylinder opposes the restoring force from the lower pressure expanded cylinder. Net work in or out = zero, neglecting friction and thermal transfer issues. Those losses still occur, but are much smaller than pumping losses.

The problem with systems that shut off fuel but not valves is that now air is getting sucked in (takes work) from the intake ducting, and pushed out (takes work) through the exhaust ducting. That ducting is a constriction that must be pumped against- head loss, like small pipes for a water pump. Those are the 'pumping losses' talked about.

IF what was on the outside of the valves was simply the open atmosphere with no constrictions to/from it, then there would be little pumping loss. But the pistons act with the timed valves as a pump, moving air through the constriction of the intake/exhaust systems, which requires work, aka using energy.

 

I would think that, and I believe that it can be found in the description of regen braking, when you coast and the chrg led's are lit, a couple of the cylinders are "shut down", meaning valves closed in order to provide some compression braking to power the motor/gen. This may also be the case when you lightly tap the brake pedal to engage regen braking. If the exhaust valves were left open, you would get no compression to power the regen braking function and there would be little or no resistance to slow the vehicle down using the EV motor/gen. There may be some energy lost as well due to the remaining active cylinders trying to overcome the compression forces of the closed off cylinders. Then again, I may be misreading something here...

 

gonavy:
Thank you for stating the obvious.

I'm stoked about driving for short periods without using gas, whatever it takes. Outside of turning my key while driving.

The 06 HCH is the first viable option for me because I've only had bad experiences at Toyota Dealerships and the Insight is not practical for my needs.