New PiP Owners...More data please!!!

Those are impressive numbers, especially with one charge per day.

 

I should add that we do use the car on the weekend to go food shopping, and I can jjuuusssssst do the whole thing EV only (one of those "will the engine turn on as I am parking the car?" deals).

While I am impressed, I am a little disappointed with the Wh/mile of 270. I thought I saw early in this thread people doing 220 or so. I could do better if I was more selective with the EV/HV button, but I usually save EV for the drive home, as there is more stop-and-go slow-roll traffic. There are too many shallow hills that just drain EV going up them from a dead stop on my drive. I wonder if the people with low Wh/miles are on more level terrain?

 

Blending Optimizations:

Based on initial observations as well as PC posts it appears that blending is a good strategy to warm up the engine. Blending is a technique where both the electric and the gas engine run while the gas engine is warming up. The PiP doesn’t have an explicit “blend†mode, but switching into HV mode and switching immediately back into EV mode effectively results in blending, since the PiP will use the electric engine but continues to run the gas engine until warmed up.
Assuming for now that blending is indeed a good idea (I will try to validate that assumption in the future) I asked myself the following: For the use case where I start out driving X miles on electric followed by Y miles on gas does it matter when during X I blend – i.e. should I blend right as I start or should I wait to blend till the end of X? (In both cases would I start Y with a warmed up engine which above we assumed to be a good thing).

So I ran the following experiment: I drive 5.8 miles from home to the freeway onramp. Temperature has been pretty stable (between 48 -55 degrees). There is virtually no traffic and few lights, making repeated trips highly comparable. I measured 5 trips (A) in electric mode, where I initiated blending (by briefly pressing HV, then going back into EV) right as I left home. In addition I measured 5 trips (B) such that blending completed (i.e. the gas engine would turn off and I would be 100% electric again) just a bit before the onramp. Since I am not aware of any method for measuring electric energy consumed I recorded how many electric miles I used up. I also recorded the MPG for the each trip.

From the MPG I can easily calculate the amount of gallons used. I also converted the electric consumption into gallons – for that I matched 50 electric miles with 1 gallon, as my alternative to electric range is a 50 MPG hybrid. Then finally I added actual gallons used plus electric miles converted into gallons for a trip total. In the end I took the averages and compared them – it turns out that it is 11.2% more efficient to blend at the end than it is to blend at the beginning (see the attached spreadsheet for details View attachment blending experiment.xls ).

There is of course quite a bit of noise in the data, but 11.2% appears to be significant. I was very surprised as I didn’t expect to see a difference. Anybody with technical background have an idea what would make blending at the end more efficient than blending at the start? Does it help the gas engine to warm up if the car has already been driven a few miles in electric? I am also curious if others can reproduce this or if there are other factors playing into the results that I didn’t consider. (Please note that I am assuming that the engine warmup for my continued trip on the highway is equally good regardless of whether I am warming up at the beginning or the end – even though warming up/blending at the beginning might lose some of the warmup by the time I get to the highway, which would be an additional benefit to blend at the end. However, my experiment is not able to account for that consideration).

 

I'd say my daily commute is pretty level. Going to work, there's a difference of about 600 feet of elevation (downhill). Most of that descent is in the first few miles. Its 13.4 miles to work and I make it every morning on electric. Coming home, I consistently run out of EV range about 1.5 miles from home (often times my warm-up finishes right before I pull into my driveway). My last tank (which isnt necessary that indicative of my normal driving, but close enough) was 219Wh/mile.

Although you may be able to increase your electric efficiency as you said, I think you're still doing pretty good as it is on a single charge and ~40 miles per day.

 

I'm thinking.. if you blend right as you leave the house, you're not allowing the warm-up to add much to the battery since its full? But if you blend at the end, all the unused energy is sent back to the battery?

That may account for some of the difference.

 

If you warm up the engine at the beginning, then go back to EV, the engine is losing the warmth that was put into warming the engine for the duration that you are in EV. If you warm the engine when you need it, then the engine is not losing that warmth while you are in EV.

Anyhow, thanks for actually testing this. I'm pretty sure I saw this as well, but there have been temperature, traffic, and route variations for my commute, so I wasn't able to isolate the effect.

 

i am averaging an MPGe rating of around 160 mpg in my Leaf. throw the cost of the electricity you pay into the equation and determine your cost per mile then divide that by the cost of the gas you pay

your 192 MPG sounds impressive but if you are paying a high rate for electricity, you are only telling half the story or in your case only 32% of the story

 

one way i would do it is by cost. i will ad liv some figures for example of $4 for gas, 10 cents per K (my local figures)

your cost 8.379 gals of gas @ $4 = $33.51
juice 55 KW @.10/K = 5.50

total cash output 33.51 + 5.50 = 41.01

drove 691.2 miles so cost per mile 41.01/691.2 = 5.93 cents per mile (my standard Prius averages about 8½ cent)

now to figure MPGe is cost of gal of gas divided by combined miles per gal cost or $4 / .0593 = 67.45 MPGe

pretty close. this way does allow you a way to verify stats the car is putting out

 

These are great results!

Please add your fill-up data to the spreadsheet in this link thanks.

 

well that be obvious now would it?? you dont save money when step #1 is paying $30,000 plus for a car.

but try to tell other people that. i have been in the hybrid/EV game for a long time. i have shown my cars, talked with a ton of people and I can tell you one thing;

get the math ready because without that. 90% of people will not hear what you have to say

on your figures @ 10 cents per K you are averaging 3.5 cents per mile

so your MPGe rating would be 109.68 MPGe...still very impressive numbers!

 

Maybe you should call it MPG(cost equiv) to differentiate it from EPA's MPGe?

 

i will take that into consideration.

what is your definition of MPGe?

 

EPA's definition, in plain words: total miles driven divided by total energy invested.
Total energy invested expressed in gallons equivalent, where 1 kWh is 1/33.7 gallons.

 

Agree with your point (I mentioned that consideration at the end of my post). However, please remember that the "quality" of the engine warmup had absolutely no impact on my measurements, as I didn't measure how the engine performed once I used it other than the blending (I haven't measured it since that alter portion has highly varying traffic and makes fair comparisons impossible). But as per your point I would definitely expect the "just in time" warmup to be more effective - but my numbers don't prove that either way.

 

Thank you for that number! Just yesterday I was calculating if I could justify the extended battery pack offered by Enginer for the PiP. I looked at the cost, where I can convert kWh into gallons based on cost. Then I wanted to convert based on environmental impact and got stuck - your number is what I was missing.

Do you know how EPA established the number? True environmental impact obviously heavily depends on how electricity is generated. Is EPA considering a US average? Plus is the negative impact of producing and eventually recycling a battery taken into account in any fashion?

 

Sorry, it's Friday night here and I have to quit.
Try Google MPG(e) or at Wiki.
There is also ton of data on subject in various threads of PC.