97 MPG commute ... aiming for 100!

I don't get these high numbers. No matter how hard I try I can't get anywhere near that...

 

Hi Ron,

My biggest surprise in reading data from Scangauge was the average speed, but then I realized it includes driving in heavy traffic and stopping for stop light / signs. Could be sitting at a red light for 2 minutes - you're not moving thus your average speed for the total trip is going down. More red lights ... and heavy traffic ... you get the message

Gabe

 

Well done Jim, I'm very impressed. Did you make any big changes or is this the result of just fine tuning? I notice the ICE use dropped from 29 to 25% and it took about 10% longer, does that sum it up?

 

Wow! Waiting for the detailed write up...

 

What is the AH: 3.83?

Is it the average amp drawn from the HV battery?

 

Great job Jim!

That only functions for Plug-In Prius. It lets us know how many Ah we took out of the battery. It comes in handy to find out how much longer we can travel in EV mode.

 

So all this is with a plug-in?

 

No. Jim is doing it all on a stock Prius. The CAN-View is used for plug-in's but any prius can use it. Its kind of like a ScanGauge but more useful.

 

Thanks! I didn't know CANVIEW could be installed in a non-plug-in. Now is there a formula to convert the electricity used for the EBH to equivalent gallon of gas? If so what would be the equivalent MPG for a Prius without EBH? Thanks!

 

Oh I see. Since the HV battery pack is rated at 6.5 Ah, it is at about 60% SOC. Prius use the HV pack between 40% to 80% state of charge and aim to stay at 60%.

 

Somewhere there was a brief mentioning of a Japanese driver who keeps the charge level low to get higher charging efficiency. Any idea/data?

 

JimboK,

Congrats on the ++ MPGs. Guys like you are a constant encouragement
to the rest of us Gen II owners.

I routinely get 55ish MPGs on my daily summer commute. I recognize
and accept that the nature of my mostly urban driving in limiting. On
rare days when traffic is light and I hit the traffic lights just right I'll get
low 60s. With guys like you way out in front, everyday is a new challenge.

With the HSD, there are many little operating details that at first blush
appear to be counterintuitive, eg, not using the HV battery for primary
propulsion. But if you look closely, they are based on sound principles,
in this case MPG reduction due multiple power conversion losses.

I think I need a little education on why keeping a low HV battery
charge level -- as seen on the SOC screen -- would be a good idea.
From my experience this idea really is counterintuitive. I'm usually
trying to keep a high SOC and get no HV charging at all.

Some background: I have a ScanGauge, so I can read RPMs, etc. (But
in fact, I'm kind of lazy and I don't do a lot of gauge switching when
underway.) I have noticed that when I'm on the highway, cruising
steadily on Cruise Control, the HSD likes to keep the SOC up around
high 6 blue bars -- 65%+ on SG -- and even into the first green bar --
67.5+ SOC. I take these SOC conditions to be indicative of what the
HSD considers most desirable/most efficient.

So when I drive, I look for opportunities within the accepted
algorithms to get and keep high SOC. Those algorithms would include:
* minimize regen -- yes, some does happen down hills, etc.
* maximize no arrows glide
* accelerate in the 1600-240 RPM band
* whenever possible drive at speeds/RPMs that result in no energy
flows into or out of the HV battery.

I have noticed that at lowish SOC conditions, 50% as an example,
RPMs are higher, as the HSD "bleeds" off power through the power
split device to MG1 to raise the SOC. At 65% SOC under the same
conditions, -- including speed, topography, etc. -- RPMs are lower --
no power is directed through MG1, and I'm assuming MPGs are higher.

My question then is, if my understanding is correct, why would trying
to keep SOC low be a good idea?

Like it or not the HSD is going to bleed of power at every opportunity
to charge the HV battery to it's preferred ~65% level. Yes? No?





.

 

See here for the Japanese driver's SOC strategy (again it was just brief description):

World record distance on a single tank for a Prius II - Japan - July 4 - Aug 16, 2006 - CleanMPG Forums

 

GREAT! Gives the rest of us something to strive for! Good job.

 

Thanks for more detailed info! I am also very interested in finding out the best acceleration rate, since "glide" is easy but "pulse" can be hard or soft and there are different opinions out there which one is better. Please keep us posted your findings. Thanks!