The 06 HCH is advertised as being able to run in electric-only mode 'under certain circumstances during low-speed cruising', but I've never seen anything that defines what those circumstances are.

Since there is no 'EV' indicator on the dash and there is no perceptible sound or vibration difference when running in electric only mode, I'm defining 'EV mode' as the state where the instant MPG gauge is pegged out at 100mpg and one or more bars of assist are showing. Based on my observations of the instant MPG gauge alone (is there a standard GreenHybrid acronym for that?), the ECU seals the valves and cuts off fuel to the ICE whenever I take my foot off the gas, but only if there are assist bars showing (and the car's speed is maintained) is the electric motor actually propelling the car forward.

Anyway, I tried several times last night in my neighborhood to enter the magic 'EV mode', but to no avail. Maybe it's because the car is brand new, or maybe it was because of the lower temps last night (low 50's). Today I had much better success (70's). It always happened in the 25-30 mph range and I had to hold the accelerator very steady. The slightest extra pressure or moderate incline would make it start sucking gas again (instant MPG no longer pegged at 100). But, as easy as it was to go out of EV mode, it was also easy to get back in. I was able to sustain it for up to 30 seconds at a time, but I usually lost it because of environmental factors (incline, traffic, etc.). Once I was even able to sustain it up a small incline (3 assist bars)!

The ECU seems to be very efficient at only flowing the gasoline when it absolutely has to. And, since the ICE remains spinning, there's no overhead associated with spooling it back up. I would guess that on a closed, flat course an experienced hypermiler might be able to sustain it for long periods (perhaps limited only by the current battery change) and get a LOT of miles out of a tank.

Did I mention that this car is loads of fun?

 

Hi NASAngineer:

___Great to hear about its EV mode as I was waiting for one of you to describe it! Now onto fantastic FE while under this built in EV mode. Once you are in this quasi EV mode, slowly bleed off speed on any small ascent or flat to maintain it (with or without assist) but without any regen. Forget about regen until you absolutely positively have to hit the binders. This is a Glide/EV in the Prius II/Escape HEV and you will want to use it as much as possible while in any deceleration or flat slow speed cruise. The second question will be is how much SoC did you lose over a minute’s time? The HCH-II’s pack is only good for ~ .5 KWh and that will not drive the HCH-II that far in EV but with a slowly declining speed, it will go a lot further then you would imagine … Start pushing and do not forget to get those tires pressed up and that oil swapped out in a few thousand miles. If not, most of your HCH-II’s capability will be thrown away towards an average LMPG vs. a spectacular one or what it is actually worth.

___I look forward to hearing more about your HCH-II and if you can coax some of its secrets out early on and post them here, it will help those that follow achieve higher FE in their own right off the lot.

___Good Luck

___Wayne R. Gerdes

 

I haven't tried to engage EV mode and the only times the car happened to enter it was on my office's parking lot where I would just naturally creep around while barely or not pressing the gas pedal. It would be very obvious when the car is actually propelling itself and not coasting and it was kind of fun, though of course you get alot more of that driving a Prius.

Coasting is more impressive, really -- how the car turns the engine off at any speed when you coast but it keeps spinning so there is literally no vibration when it starts ignition again. That allows it to turn on or off repeatedly at 80 mph with no harm done and it definitely helps.

 

Hi CGameProgrammer:

___Did you just say that you are in an ICE-Off mode at any speed while coasting down? Not a regen/Fuel Cut mode but ICE-Off in an almost free coast? This is something new indeed!

___Good Luck

___Wayne R. Gerdes

 

Wayne, the ICE is not stopped but it is off. It likely takes more energy to disconnect the engine from the wheels and then reconnect it and bring it back up to speed than it does simply to let it remain connected, so that's why the engine is only literally stopped when the car is not moving. Even in EV mode the engine is still spinning because the wheels are.

 

Right, and the 06 has several enhancements designed to reduce the friction of a spinning engine, like aluminium pistons to reduce heat expansion, ion-plated rings, etc. Their view is that the majority of spinning friction comes from aspiration, which they have eliminated in the 06 by sealing the valves when no fuel is flowing. The ICE only stops spinning during auto-stop.

 

I haven't figured out yet how to make the transition straight from 'quasi-EV' (fuel flow off, but no assist) to full EV without the fuel flow kicking in in between. That might just be a lack of skill though.

I wasn't monitoring the SoC closely, but I don't think it ever dropped below 50%. I'm not sure what the .5KWh translates to in terms of seconds of full EV, it depends on how much power the DC motor has to generate to keep the car rolling at 30 MPH. Empiracilly, it seems like 'not much'

Thanks for the tips! I feel like all of the reading I did here on GreenHybrid before I got the car was like completing ground school, so I'm learning more quickly. We'll see how long that lasts though

 

Speaking of tire pressure, how significant is it really? I don't even know my tire pressure, I just drove the car home from the dealer and forgot to ask them to pump up the tires.

 

It seems like the 06 HCH is quite different than previous versions. Any driving tips would be greatly appreciated.

 

Hey guys; this is really interesting reading. I may have missed it but what are the readings for FE on your two HCH's at present?

Second thought I think I now remember that maybe one of you on another post made the comment that you were not going to talk about FE readings until you finished a tank of fuel and you were ready to do a refill. If that is the case I guess we will just wait for the updates on FE.

Great-Info.

Terry