Using EV mode to Pulse and glide above 42MPH?

cleanmpg.com has a good tutorial.

 

When you are in EV mode you can use EV to 62 mph if there is enough battery charge. When you are in HV mode it is effectively a standard Prius so EV only works up to 42 mph.

 

45'sh MPH in Gen3, but otherwise correct.

OP is missing why P&G is a beneficial technique in some, but not all driving scenarios. Thus the need to read a tutorial. Hobbit is best, cleanMPG second.

 

Yep, this is the "hidden gem" in the PiP, if you are willing to work it. I routinely get 80+ MPG on 100-mile (mostly) highway trips this way. Thank God they added that HV/EV button for the production model

 

How fast do you drive -- average highway speed ? I'll guess ~ 55 MPH.
Is the 100 miles a round trip ?

 

hey! i resemble that remark.

 

No offense intended, I assure you.

If Iluvmacs drives at the speed I suspect, P&G is not adding anything to his fuel economy. I'll show the math if he confirms my suspicion.

 

Highway 55MPH limit, and I'm not doing significantly more than that except perhaps on a big downhill. This is a one-way trip, but the MPG each way is pretty similar. I should be more clear in my technique that I'm using the EV-mode glides primarily on downhills and other times when speed is intentionally decreasing (i.e. speed limit goes down or coming to a stop). I don't really do highway P&G in flat areas in the "classic sense" for various reasons.

 

^^Thanks.
Let's use 55 mph all the way then

Wayne Brown has calculated that the Gen2 Prius consumes 203 Wh/mile to overcome frictions at 55 MPH
BobWilson measured 64 MPG in his Gen3 Prius at 55 MPH

So now we can compare your modified P&G technique to the most basic: drive EV mode until the battery is depleted, then HV mode -- all at 55 MPH.

• IIRC the traction battery from full to empty is 3.2 kWh, so that is worth 15.75 miles
• For the other 84.25 miles, the HV mode will consume a gallon every 64 miles, so 84.25/64 = 1.32 Gallons

Then 100 miles consumed 1.32 gallons, for an MPG of 100/1.32 = 75.7 MPG
This is well within the expected margin of error just for differences in tyres (Bob's were new), or tyre pressures, or road quality.

So I'll say it again: P&G is a waste of time at highway speeds. Energy analysis suggests it might even be a bit worse. OP would be well served by understanding P&G so that he knows when it is beneficial.

 

You won't have near the gains you would see relative to Pulse and Glide at slower speeds.

IMO the gains aren't worth the work, but to each their own.

 

The longer you can remain in a state of "infinite MPG" (e or otherwise), the better both EV and HV will be. So your glide - or coasting is the key. Regenerating is nice, but it costs speed. On an extended downhill if you glide rather than regen, you won't impede traffic. And due to the Prius' low coefficient of drag (0.25), you can glide for quite awhile without losing momentum. But whenever you regenerate, you lose speed and momentum due to motor friction. So there's a bit of a choice to be made. My "to work" travel takes me from about 800 ft above sea level to sea level. So there are a few places where there's gliding to be done. But on a few steeper downhills, it makes sense to regenerate (as long as I can keep my overall speed equal to or less than 62 MPH so that I don't slip into ICE mode).

And layered on top of it all is avoiding pissing off of the rest of the freeway traffic while motoring below 65MPH. It's definitely an art (as well as a science!)