Is this crazy high gasoline mileage!?!?!

I've gotten some of my best fuel economy as a 'D' student.
The teacher is not only wrong , she is inconsistently wrong.

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I had a very nice drive today:
96 miles r/t trip in the Southern Rockies to go fetch my E-bike. That thing is awesome.
1 full battery charge
115 MPG, so 0.84 Gallons

I used 94% of my battery out (48 miles) and had ~ 185 mpg
The return trip used up that 6% and showed 83 mpg. If I wasn't annoyed by ICE use I would find that to be most impressive.

 

EV Auto would work for a trip like that, but it will lean more heavily towards EV miles than you may think.

In my experience, EV Auto works differently if the ICE has already been warmed up or not. If the ICE has not turned on yet, the threshold before the ICE engages is significantly higher.

However, regardless of whether the ICE has already been warmed up, EV Auto does not engage the ICE on flat ground at standard freeway speeds at normal acceleration rates (55 to 70 MPH). Typically, I will only see EV Auto engage when going up a hill at those speeds, or if I floor the pedal to get out of the way of another approaching vehicle. If the ICE has not turned on yet, the EV mode has to get pretty close to the PWR section of the HSI in order for the engine to kick in.

 

I chalk up its utility right up there with Charge Mode.

My main objection is that the ICE is engaged cold during a power surge. Then it stays on to go through the warm up steps ... and then shuts down and the ICE cools off. It pretty much runs counter to how I want the car to operate.

 

I agree that in the majority of instances, EV Auto is not the ideal mode, and I am glad that it is not the default. I also don't like to engage the ICE cold during a power surge, and I typically avoid EV Auto unless the engine has already been warmed up.

That being said, I find EV Auto useful on some of my (numerous) 50+ mile drives where I have traffic on the middle portion, and I can plug in at the destination. On some of these drives, I enter HV mode after bleeding a couple of miles off the fully charged battery, then switch it to EV Auto with around 35-40 miles left on the journey (or when I hit traffic, whichever is earlier). That way, the ICE engages when already warmed up on some of the uphill portions.

That said, I used that strategy more when it was colder when I could take advantage of heat from the engine in addition to the heat pump. In these warmer months, I often just put it in drive and go (EV mode to HV mode), or go HV for the first batch of miles and then switch it to EV (not EV Auto) where I believe I will hit the destination just as I deplete the charge. I get superb mileage all four ways...

Final thing - pro tip (straight from the manual):
- If one is driving in EV Auto and wants to switch to HV mode, press the HV/EV button.
- If one is driving in EV Auto and wants to switch to EV mode, press the EV Auto button (it's initially counter-intuitive, but makes total sense)

 

So guys, is there any estimation at all involved? Doesn’t the computer know exactly how much fuel it injects on each cylinder pop, and of course how much distance it travels?

 

I would think so. The only two possible explanations I can dream up are that either the fuel meter measures a little inaccurately or the calculator flat out lies.

 

That’s possible. I suspect though that there are trips where we do indeed get dang-high mileage, but others where it’s not quite as high, and altogether average out at around 56ish.

 

Probably true. It's just not been my experience on any of the previous generation Prii that I've owned (4 so far). But, as they say, ymmv.

 

My experience is that EV auto mode only kicks in when extreme demand is put on the car as in when lots of acceleration is needed. Otherwise my vehicle stays in EV mode at high speeds but gobbles up lots of electric energy making in fuel inefficient. But I must admit I have had little experience with the mode setting thus far.

 

Yeah, I personally don’t see much point in EV-Auto mode, as best I understand it (I qualify that with “as best I understand it,” because I’ve never seen any need to try it so far).

I could see it being possibly useful if it were defined as a more extreme, “meta-hybrid” mode, by which I mean, essentially, strictly EV below ~45MPH and hybrid above that.

 

I’m in the same boat as you and honestly I can’t believe it. I have ~300 miles on my car, charged 3 times and have 9/10 of my tank left.

 

Yes this is real. Prime is much more efficient then earlier Prius. I have put 22000 miles on my 2017 Prime in Vermont, mostly at speeds of around 50 mph. At that speed, after all-electric range (23 in winter, 33 in summer) 65-70mpg in hybrid mode is typical with around 50% energy recovery with braking and going down steep hills. Less on highway at 70 mph because of wind resistance. My useage is 50 % all-electric and 50% hybrid mode and on first 22000 miles, I have averaged 136mpg = double the 68mpg in hybrid mode. On a recent long trip of 2100miles (150 miles/day) with plugin only at night I averaged 82mpg.

 

I’m not really sure what I get on our P.Prime in town, because I almost always drive on EV in town. However, on road trips at 65-75MPH, driving strictly in HV mode, I typically see around 58MPG. I expect it would be a little higher in town.

I’ve occasionally thought about resetting it all and driving on gas in town for a week, just to see what I get, but “gas! eeeeew!”

In all of this, be mindful of long-term-average mileage vs. that on individual trips. Some individual trips can have very high mileage, but the overall mileage over a wide variety of driving circumstances will be lower, but still dang good!

 

I was curious, so I did that for a whole tank on the PiP earlier this summer with normal commute. Cost $0.479 per mile and got 55.79 mpg. Slightly better than a road trip on the Interstate.

 

$0.0479, right?

 

Yap, I did the exactly the same thing with my PRIME for full tank earlier this summer. I got 620 miles of HV only range on 10.1 gal of gas with 61.2 mpg calculated (66.0 mpg displayed). That is 10mpg better than what I was getting from Gen3. I planned to do the same thing again in winter.

 

Unless he buys gas at an airport.
Pilot joke.

 

FWIW, including weekends, our P.Prime uses about 65KWh per week (and no gas to speak of).

Charging at home (including all per-KWh costs), it works out to between 10-13 cents per KWh depending upon home-air-conditioning usage that time of year (main factor as to which rate tier we’re in). It works out to around 2.3-2.8 cents per mile, as opposed to around 4.8 cents per mile for gas at current typical gas prices. Around half of gas $/mile.

However, about 45 of those 65 KWh come from chargers around town under Austin Energy’s Plug-In EVerywhere program, which I nickname “the dollar-a-week plan” ($50+tax per year for all you can charge around town). So ~220 of our ~315 miles per week, only cost us $1. (Charging from home, $1 would only get us about 40 miles, instead of ~220!)

So anyway, our ~315 miles/week altogether ends up costing us ~$3.40, or about 1.1 cents per mile! About 1/4 of gas at 55MPG!

So, imagining that I can keep that up for a 200Kmile lifespan of this car I will have saved around $7400 on fuel costs alone! The big savings though is that I’m putting almost no miles in the engine, so I bet I can keep the car for 20 years, and shelling out $30K once every 20 years, rather than once every 12 years, represents big savings!