800+ Mile Club

He had *at least* 20 miles to go on the tank. What a waste

 

Wow, did I see correctly that the Scangauge had you at 66.X mpg and you still went for it.....Wow! Brass ones on you!

Congrats!

 

Thanks. Yes, I was only able to get 66 mpg on the last 12 mile trip to the gas station. Strangely, from the gas station to work (10 miles from Rockville, MD to Bethesda, MD) I was able to get about 93 mpg (with a pre warmed up engine). For the last 100 miles of the 800 mile tank, the Scangauge Flv xgauge seemed permanently stuck at 0.7 gallons, so I was basing my remaining range estimates on 70 mpg x 2.1 gallons (Bob Wilson's measurement of the amount of gas left after the first beep) + <odometer miles at the first beep> = 658+147 = 805 miles. FWIW ...after a fill up the Flv xgauge registers between 11.5 to 11.3 (not 11.9 or 12.1)... the fuel tank sensor is not all that useful when you get to that last gallon of gas.

 

great show Walter, congrats on the 800. I think I would have wimped out way before that or started carrying fuel with me

 

Hi Walter Lee
Looks like you're hypermiling very well !
I've seen you have a couple of sg 2 fitted on your P3 dashboard.
I have 2 questions for you: which is the meaning of the xgauges IGN TPS FLV GPH?
In which way does they help you in hypermiling?
I find helpful also reading ampere from and to traction battery.
Have a great hypermiling time over there!!
Greetings from Federico

 

Ferls80,

IGN=22/TPS=19 (approx) is use along with RPM=992 to 1100/ GPH=.50 to .75 to approximate super highway mode which is a very low power ICE mode I use to climb uphill quite frequently. It's a variation of driving with load (DWL) because I'm borrowing SHM techniques to do the uphill climb. On the downhill accelerate at about RPM=1100-1400/GPH=0.90 to 1.4 to the +X mph(e.g. X=20) of target speed at the bottom of the hill (e.g. 50 mph) then throttle down to superhighway mode and pray that the prius speed doesn't drop below the target speed (e.g.30 mph). If I am successful = the AVG at the bottom of the hill is the same when I reach to top of the hill. If I fail then the AVG at the top of the Hill << the AVG at the bottom of the hill. I still have occasional problems preventing the SoC dropping below 48% which causes the automatic recharging of the HV battery the subsequent lost of MPG/range. The SoC tells me when I need to focus more on the Pulse than the Glide.
FLV = gallons of gas in the Prius (top= 11.5 ... bottom= 0.7)

hope this helps
Walter Lee
aka Hyperdrive 1
2010 Toyota Prius III

 

Walter how do you have an 800 mile tank but yet not on the 99.9 trip list?

 

Is this a Prius only club ?

 

This thread is specifically for the 2010+ liftback.

 

Any non plug in Prius can apply.

And John, what type of vehicle were you thinking?

 

I haven't gotten there yet ...
but it is on my list of things to do...

 

Walter Lee
Thank you very much for your reply.
I'll try to hypermile with all the indications and xgauges learned from you.
By now I found helpful those xgauges:
Ice temp: tells about ice thermodynamic efficiency (best is around 88C) and in which stage (S1, S2, ...) HSD is.
Ice rpm: according to the engine efficiency map, the best ice rpm range is from 1250 to 3000 rpm. On the basis of some practical tests the best working point is around 1600 rpm.
Soc (State of Charge): staying at 60% is the best way to avoid waste of energy in conversion. More, if you are below 60% you can drive aiming to recharge battery, otherwise if you are above you can extend the glide phase.
Amp (ampere from and to traction battery): helps to find the best gliding point, and the best breaking way.

 

Each model of Prius has its own strengths. Having a dedicated thread to point out each is nice. So, I'll refrain from PHV references here and point out that I typically didn't drive beyond 500 miles with my 2010 before refilling.

 

A PHV is a quantum leap in tech - wrt to fuel efficiency, on the forums in cleanmpg.com members are looking at 8 miles per kilowatt/hour as being very good for a hypermiler and 4 miles per kilowatt/hour as normal. However, in mileage logs things get more difficult to quantify especially when integrating both electrical and gas fuel efficiency into an aggregate metric. For example, in cleanmpg.com's top 50 hybrid mileage log - PHV MPG results for a Chevy Volt (wittesvolt) listed on cleanmpg.com mileage log with an +440 mpg [1]. However, the reason for this high results in the cleanmpg.com mileage logs is that mpg is computed by only looking at the gasoline usage and not the combine usage of gas and electrical power. Hence, if a Volt travelled 1550 miles using 1.5 gallons of gas and 413 kwh - only the gas is considered so it computes to be 1033 mpg! The "Wittesvolt" Chevy Volt's fuel efficiency looks less stellar but more realistic if both the gasoline and electrical fuel usage are accounted for separately. Let's say we subtract 50 miles from the range from the Chevy Volt (EPA gas FE is 35 mpg) based on the 1.5 gallons used so we are left with 1500 miles travelled on the 413 kwh used - this translates to a very normal 3.63 miles/kwh - Not extraordinary for a plug-in or a BEV but respectable and more believable. In washington DC , regular 87 octane gas cost at $3.80/gallon after taxes while electricity cost is about 16 cents a kilowatt/hour after taxes. Given that HV battery recharging process is about 80 percent efficient ( it take 1.25 kilowatt hours of residential electricity to store 1.00 kilowatt hours of power into the Volt's Li-ion battery) it actually cost about 20 cents per kilowatt/hour of Hv battery power. This means that for $3.80 - you can get either 1 gallon of regular 87 octane E10 gas or 19 kwh. So we can compute the Volt's equivalent gasoline fuel efficiency as being 19kwh/(eG) * 3.63 miles/kwh = 68.97 miles/eG. This is very good but it's not 1033 mpg. However, given that my last hypermiled tank, my 2010 Prius go 71.1 mpg using regular E10 gas , the driver's volt's 68.97 e-mpg results don't seem as impressive given the Volt's overwhelming tech advantages and its significant premium. sigh.

[1]
CleanMPG, - Garage An authoritative source on fuel economy and hypermiling

 

Fix these units, or I fear the electricity gods will strike you down where you stand.

 

Whoops!
Geez how did I get electrical power and homocides mixed up like that?
Someone is making a killing off those extra fees and taxes on my electric bill... but it isn't me...

 

I agree that you should also consider electricity use but it's very difficult to evaluate apples and oranges. Volt driver would say use as much electricity as possible (hypermiling is not necessary), Prius Plug-in driver would say drive in a way that you use as little gas and electricity (small battery) as possible.

- One way is to calculate price of gas and electricity used, but every user will come up with different number for electricity they pay and also gasoline (Europe anyone).
- You can calculate energy content of gas in kWh and add that to electricity use. This for me is the one of the most accurate calculation, but it also poses a question how much energy was necessary to generate electricity? The other argument is that electricity can be generated from sources that can not be directly burned in a ICE. Also gasoline production is not considered in energy content of gas.
- There will be argument that charging Volt from PV does not use any energy at all, but I think we are not there yet and our Electricity production is still generally bad for environment, so using less kWh/mile will always be good.

 

I agree that since the price of gasoline and electricity goes up and down - any estimation equivalence based on price is temporal at best. A more stable aggregate metric would be better.

While I get my electricity from "Clean Current" a wind turbine electricity consolidator, I must buy about .3 kwh from my local utility - PEPCO - for each 1.0 kwh of electricity I buy from "Clean current" just to pump it to my house. PEPCO uses a combination of coal, oil , natural gas, and nuclear power to generate that .3 kwh of electricity - so PEPCO's .3 kwh not that good for the environment. PEPCO is on the short list of not environmentally friendly electricity providers and they are not buying any carbon credits so there is no environmental offset to using its dirtier electricity. Since I don't own enough land to support a PV array good enough to recharge a BEV or PHV - a PV off the grid solution is a no starter for me. So for the environment, it is better for now that I just use less electricity.