Ultimate driving technique for highest MPG

You can read all about the event, which took place last summer, in an earlier PriusChat thread:

http://priuschat.com/index.php?showtopic=1...l=West+Virginia

The consensus on the technique for getting the highest mileage is something called "pulse and glide." You'll find everything you need to know about this technique if you do a search for it within PriusChat.

 

I think the best Prius mileage would be obtained by calling AAA for a tow, but not for the towing vehicle. Or Amtracs AutoTrain (does it still exist?).

Other than pulse and glide I think it might be going downhill while drafting a tractor/trailer.

FWIW, others have tried the most miles from a tank. My advise is don't do it, or if you absolutely have the need, be sure to have a spare gallon of gas in the car with you. The MFD gives a fairly accurate readout, there is no possibility of running out of gas with just a little care, so lets compare MFD mpg not total miles per tank.

Same as any other vehicle, when it's out of gas you are SOL. Don't even think of using the battery to get you to a gas station, that isn't what it's for.

 

<div class='quotetop'>QUOTE(mdarby @ May 25 2006, 04:04 AM) [snapback]260457[/snapback]</div>

I don"t know where you got these techniques, but it is wrong.

wrong - maintain about 40 mph
correct - pulse up to 40mph, then glide as soon as you finish pulse.

wrong - coast to 30 mph to recharge the battery
correct - coast to 30 mph with no energy arrow - no regen or no battery use

http://hybridcars.about.com/od/ownership/a/pulseandglide.htm

Ken@Japan

 

Most efficient is always drive downhill.

 

1. Anticipate traffic
2. ICE off, or running 1800 - 3000 rpm
For (2), if you do not have an rpm read, go driving for a bit and when the HV SOC is four bars, listen to and learn the engine noise when you are driving at a steady speed and gas pedal position that shows the engine on, but no HV flow on the MFD energy flow screen.

3. The limited capacity of the HV may require a bit of management. If a part of your drive e.g. a long downhill fills up the HV, try to start that portion with a low SOC.

WINTER
1. Combine short trips
2. Combine short trips
3. If *really* cold, block heater or radiator semi-block. Know what you are doing.

SUMMER
1. Tint, window shades
2. Learn to use the climate control: First windows open if the cabin is much hotter than ambient air. Then windows closed, AC on, fan high, temp at the highest you find tolerable/comfortable.

 

<div class='quotetop'>QUOTE(EricGo @ May 25 2006, 11:36 PM) [snapback]260876[/snapback]</div>

The engine block heater improves short tip mileage in all season.

Ken@Japan

 

<div class='quotetop'>QUOTE(mdarby @ May 26 2006, 01:29 PM) [snapback]261407[/snapback]</div>

possibly, the technique came from cross county endurance racing, i believe. i've also heard of people modding an older manual crx so they can turn the ignition off via a separate switch. then using forth gear to spin the engine back up instead of the starter before starting it again.

 

<div class='quotetop'>QUOTE(kDB @ May 26 2006, 04:58 PM) [snapback]261495[/snapback]</div>

So heres a crazy question. For high mileage on the highway, how about a switch to disable battery charge.

An "anti EV" switch?

 

<div class='quotetop'>QUOTE(Hostage46 @ May 26 2006, 05:26 PM) [snapback]261504[/snapback]</div>

we have one, it's called neutral, though it isn't exactly the safest way. i tend to use it when going downhill at highway speeds. especially if it will cause me to keep an even speed, or close to it. then again, i usually only drive late night or early mornings when there is very little traffic.

 

<div class='quotetop'>QUOTE(Hostage46 @ May 26 2006, 03:26 PM) [snapback]261504[/snapback]</div>

The actual current flowing at highway speeds is very small, often only one or two amps. The MFD shows the battery alternately charging and discharging, back and forth once every few seconds, but CAN-View shows the alternation to happen several times per second, very rapid switches, but at very low amperages.

What this means is that at highway speeds (on level ground) the car is actually doing pretty much what you are suggesting.

Note also that at a stop, with the engine off, no A/C or lights, the car draws one or 1.5 amps or so. So you cannot shut off battery charge/discharge completely.

 

<div class='quotetop'>QUOTE(mdarby @ May 24 2006, 12:04 PM) [snapback]260457[/snapback]</div>

I'm going to ignore the constraint here somewhat, but the same still applies (more or less) anyhow.

Based on my experience:
Non-highway: As others have noted, "deadband" pulse and glide, 40 to 30, while the battery is in the middle.
Non-highway, nighttime: "augmented" pulse and glide, 40 to 30, accelerating with green arrows to the battery.
Highway flats: cruise control at as low a speed as traffic safely allows.
Highway hills: Manage it yourself, minimizing hard acceleration, picking up speed on the downhills and letting it drop on the uphills.

I've played with running in neutral on downhills, and I'm not yet convinced it helped much. I suspect the car manages itself pretty well making neutral essentially not really necessary.

Take home bit: Minimize battery usage. Any interaction to or from the battery comes with inefficiencies that ultimately come off the bottom line of your fuel budget.

Key thought for the day: I find that the hardest part of pulse and glide is to keep your damn foot off the accelerator until reaching 30 (28?). However, when traffic permits me to safely glide to 30, and I take advantage of the option, I unequivocally get my best mileage. Pulse and glide, 40 to 35 returns significantly less efficiency than 40 to 30. Unfortunately, its not really practical except when traffic is really light.
--Chris