HV MPG Only?

nope, that doesn't help.

how do you get ice only miles?

 

Just answering the title question: run a tank or two without plugging in.

 

I take my total miles at fill-up. Look at my % ev for the trip, so know my regular non ev miles. Then divide by the number of gallons filled.

 

i'm sorry, i meant this, '31 mpg when the ice is on'.

 

I'll be driving ~1,000 miles from Rhode Island to Huntsville AL. The day before, I'll top off the tank and battery. Then I'll break up the trip into roughly four, 250 mile segments, ~4-5 hrs each, at a series of constant highway speeds depending upon which trucks I follow. I'll top off the tank with each break and have a record of block-to-block time, distance and fuel consumed. I need this for trip planning SINCE @Prius Team and Toyota has yet to get fundamental engineering and mileage metrics to the EPA.

Once I get home and rested, I'll do my own roll-down metrics and share them. After all if Toyota and the EPA are going to have a spat yet sell me the car . . . well not my problem. <GRINS>

Bob Wilson

 

Ie, the Gen 4 and Prime measure their MPG as overall battery + ICE usage. I think Gen4'ers are getting around 25-40% EV usage according to the vehicle's meter. If you take that factor out you'll get the efficiency of the ICE alone without any Hybrid or Battery help.

Being at 31mpg is impressive, it's basically saying "without Hybrid mode, without the battery, this is a 31 mpg in 10-20 degree winter with extra weight to boot".

 

thanks! would be interesting to compare that to like size cars.

 

I mentioned it in the other thread but I figured I would point it out here as well - we finally sorted through our little paperwork snafu and the Prius Prime is up on FuelEconomy.gov:


2017 Toyota Prius Prime

 

while you're here, can you tell us if prime reports hv mpg?

 

I see OP has figured a way to enter data into fuelly (it shows 92.7 as of today). Does this (92.7) include the hypothetical 133MPGe or just the HV mode operation? If the latter, I am wondering what the best way to find the HV mode MPG is. Thanks.

 

OP of this thread has been gone over 3 years. I doubt he will come back to answer your question. I am almost certain his number on the Fuelly includes some portion of EV mode drive, thus inflated mpg. I use to keep Fuelly record diligently when I was driving non plug-in, but after switching to PRIME, I stopped it. It just makes no sense keeping the mpg number when EV mode drive is not included in the calculation.

As for your question on the best way to find the HV mode MPG, there isn't any easy way to have separate HV mode drive only mpg on PRIME. You can get a one-time HV mode mpg by driving a tank without using any EV mode. I do it often enough to get an idea of my HV mode efficiency. For over a longer time period mpg when EV mode drive can not be eliminated, one way I have found to estimate the HV mode mpg of the most recent fill up is to use the DTE distance displayed on the dash immediately after a fill-up.

You can use DTE/9.3 to get an estimated mpg (HV mode only).
See this thread for more detailed explanation: What is your DTE after fill-up? | PriusChat

 

I drove my new 2020 Prime completely discharged on HV mode from Erie, PA (filled the tank) to Effingham, IL when I bought it, and was getting 72 mpg on the highway until I kicked it into "CHG" mode late in the drive to see what the impact was on mileage. It dropped to 62 mpg in about an hour, having charged the hybrid battery that way to 80% when it kicked back to hybrid mode shortly before I stopped for gas.

I wish the gauges would display electric and gas separately, too, but with all the modes I can see why they don't. I just reset the trip odometer too when I want to check.

 

I did pretty much the same trip last week with my 2020, constantly varying the engine RPM for break-in, and saw about 50 mpg on the dash. Was the 72 MPG you got calculated at the pump or from the dash? Did you drive using cruise-control?

 

The DTE calculation mentioned by @Salamander_King is a good one.

Regarding figuring out the current MPG:
If I reset Trip B when I fillup the tank and then after some miles, look at the EV Mode % under Drive Monitor and deduct that from the Trip B miles, would I get a good count of the gas miles? Or is it still going to be inaccurate (excluding Charge-Mode, pointed out by @john1701a to me, for the moment)? Is this how I would figure out the gas miles at the pump? Would it correlate with the DTE MPG calculation by @Salamander_King ?

 

Unfortunately, that method will not work. The EV ratio given in the Drive Monitor is not EV MODE/Driven Mile ratio. It is for All the EV drive including the EV portion of HV MODE.

 

The 72mpg I reported was from the dash, all highway with cruise control except for pit stops. After I kicked in the "CHG" mode, and it recharged to 80% battery, I stopped for gas. 62 mpg was pretty close to matching the fill-up calculation.

 

I still wonder why there aren't infinite trip meters available. After all, 'reset' just means storing a snapshot of the readouts from various sensors and doing the math between the snapshot and the current time. With just $1 worth of NAND the car could store thousands of simultaneous trip meters.

 

We haven't checked it with "manual" calculations (miles / gallons of a tank), but just using the Prime's mpg readout #s we were around 60 mpg +/- on a HV only tank for a 70 mph roadtrip.
At 12k miles (1/3+ EV), I feel the ICE is still breaking in, though. Hopefully mpg will creep up a little bit more as it ages.

 

If you're the experimental type, try reducing your speed. The mileage difference between 60 and 70 is far more dramatic than you might expect. It isn't age or fear that slowed me down, but sheer determination to maximize MPG. Back in the day before hybrids I generally drove about 75 - 80 on the freeway. I continued to do so with my first Prius until I saw how dramatic the efficiency difference was. I didn't mind the extra few minutes difference it made on the commute to shift my mpg from the high 50s into the 70s and 80s.