Driving technique question.

Lets say i have 2 mile stretch of road which the car could do on EV only.

I used to try and maximize the EV time on that stretch....

But lately I've been thinking maybe i should try to let the car coast (with neither regen or power to the electric motor), and whenever i get to a certain speed i would just give it a little push with the ICE.

Though running on EV seems to have its instant gratification ... i think the above method gives out a better overall MPG.

Sounds like you are on the right track. The pulse and glide technique is what you are describing. Keep the ICE off as much as possible and glide (no arrows at all on the MFD) as much as possible. The energy you use from the battery in EV mode ultimately comes from gasoline, and energy in the conversion to and from the battery.

Proposed text to level the playing field for all the Prius drivers
doing the mileage marathon at the Tour de Sol rally thing:
http://techno-fandom.org/~hobbit/cars/prius-rally-hints.txt
the rally and other event stuff can be found at
http://nesea.org/transportation/tour/ with the rally rules under
http://nesea.org/transportation/tour/2006rules.php
It should be a fun time!
.
_H*

For me it depends on my speed.
At 40 mph and below you can drive on EV mode (without an EV mod) if it's flat. Above 40 mph the pulse mode (or semi pulse-where you slow down for minor hills and accelerate slower from stops-not too slow) works for me.

FILE UPDATED: added "regen braking over bumps" warning...
http://techno-fandom.org/~hobbit/cars/prius-rally-hints.txt
Again, the TdS rally and other event stuff can be found at
http://nesea.org/transportation/tour/ with the rally rules under
http://nesea.org/transportation/tour/2006rules.php
If there's a prime time to get together and geek hybrids for two
days straight, this is it.
.
_H*

<div class='quotetop'>QUOTE(hobbit @ Apr 7 2006, 10:35 AM) [snapback]236303[/snapback]</div>

I would think that turning the fan ON (with temp set to MAX COLD and A/C OFF) would be much better than opening two diagonally opposite windows, even if only a crack. Aerodynamic drag really kills at speeds > 40 mph. With the temp set to MAX COLD, there should be no heat drain off of the engine, and with the A/C OFF, the compressor wouldn't be running. The fan should just be blowing outside air into the cabin. I feel that this is more optimal even at speeds lower than 40 mph.

Apparently folding back the external mirrors would not be allowed, without also installing rear view camera(s). But what about duct taping to the fore of the mirrors? For that matter, additional duct taping or the installation of underbody smoothing?

Along the same lines, I would like to see mpg of a Prius riding on 4 fully inflated donut spares some time. Below 55 mph of course.

<div class='quotetop'>QUOTE(plasm @ Apr 7 2006, 11:31 AM) [snapback]236323[/snapback]</div>

To go along with this there was actually a Mythbusters episode dealing with this. They took 2 identical Ford Explorers with the same amount of gas and drove them around a test track. One had no fan or ac on and the front two windows down and the other had windows up and ac on they stayed at the same MPH as each other the whole time and the car with windows down ran out of gas before the one with the A/C on this is because of the friction caused by the draft with the windows open at higher speeds. So in the long run the old saying that running the AC wastes gas isnt always true or at least not at high speeds.

<div class='quotetop'>QUOTE(lowspeed @ Mar 26 2006, 05:46 PM) [snapback]230647[/snapback]</div>

It is my opinion that maximizing EV time will hurt your mileage. Ev should be used when both of the following conditions are met:

1. The SOC is high; and
2. The instantaneous mpg is low.

With the mpg low, you are producing a lot of electricity, but with the SOC high it is not as efficiently captured by the battery.

The exception is if you are coming up to a long downhill that will recharge your battery, then you should try to arrive there with a low SOC so you can capture more energy on the downhill.

Now that I have the CAN-view I am looking forward to catching a view of the amperage under the conditions described above.

they way you drive on any 2 mile stretch should change very little no matter what mode you are in.

forcing EV in the middle of your drive will do little for your tank mileage. i have many trial runs on this and i have determined that the only time an overall increase in mileage is noticable is only when using EV for the latter part of your journey.

if you run your battery down, it will run the ICE to recharge at a much longer cycle time than normal, which will reduce your mileage. so i try to make sure my battery will recharge mostly when the ICE needs to run anyway. that means warming up the ICE after extended idle (i dont mean sitting at stoplights!! we all know better than that) times AND charging the battery at the same time.

now there are exceptions to the rule but most are designed to keep your mileage from going lower and not higher.

take advantage of elevation changes. i live in a town split in half by the southern tip of Puget Sound. we dont flood (at least not in town...hard to flood the ocean!) but that is because its a very steep drop to the bay downtown from any direction making traveling east/west direction a large change in elevation. (makes for a lot of VERY EXPENSIVE houses with a view to match)

in most cases, without EV manipulation, i will max my charge. knowing this, i force EV before the downhill run because experience tells me that if my SOC is greater than about 64%, i will max out and the lower portion of the hill will be spinning the ICE to vent charge to the atmosphere (i guess that s where its going...in any event, it aint staying with me)

the pulse and glide technique will work wonders but you have to know your surroundings well. its a challenge and to be honest with ya, i enjoy it.