The second time I've done this . . . tonight.

Bob Wilson

 

Engine warm, (very) long downhill stretch?

Either that or cheating!?

 

"Engine warm" - yes
"(very) long downhill stretch?" - no
"Ether that or cheating!?" - Reword!?

Bob Wilson

 

99.9 MPG for 0 miles over a 30 minute duration?

 

Actually 0.3 miles which the MFD shows as "0 miles." <GRINS>

DISTANCE: 0.3 miles
MODIFICATION: thermistor hack (critical!)
METHODOLOGY:
(1) fully warm up car and charge battery (~20 minutes above 42 mph)
(2) regen slow down to enter a flat, empty parking lot
(3) put car in "N" and coast to a stop with minimum electrical load
and reset MFD
(4) after 'mileage bar' updates, put car in "D" and gently accelerate
to 6 mph to get 99.9 'current' bar and then put in "N" and coast to a stop
(6) repeat step #4 until all bars show 99.9 MPG
(7) take photos and have a happy

LESSONS LEARNED:
Apparently the consumption bars are averaged or created from samples above 5 mph. Just reach 6 mph long enough to get a maximum bar and then coast to a stop in "N" in minimum current load mode. This is the secret behind the 'drive up window' 100 mile bars.

In these tests, the ICE never ran. Nothing was achieved other than a cosmetic effect based upon how the USA MFD works. It is totally a battery energy management task.

The thermistor hack is necessary because the USA NHW11 ICE will lose enough heat to fall below 60C and auto-start. The thermistor hack keeps the ICE off except to recharge the battery without throwing a code.

On a serious point, I'm planning to do a series of controlled, 1-liter benchmarks. My last test achieved 99.9 MPG on the consumption display over a distance of 5.5 miles. A stable protocol, I can go as many miles at 99.9 MPG as desired. However, the MFD mileage bars were 'ragged.'

This hack will let me finish each, 1-liter test with a set of solid bars and the miles for each liter. For the record, actual MPG will be calculated from accurately measured fuel burn and distance covered. After I've gotten a good sample set, at least four, 1-liter tests, I'll post the individual results and photos.

http://hiwaay.net/~bzwilson/prius/pri_test.html

Bob Wilson

 

What's a thermistor hack? Googled it and couldn't find any good hits.

 

It is a work in progress:

http://hiwaay.net/~bzwilson/prius/pri_temp.html

Clive Burke in "Prius_Technical_Stuff" had proposed using a resistor to fool the engine controller into thinking the engine was warmer than it really was. This allows ICE autoshutdown sooner and you can even get some heat from the warm, not so hot, coolant.

I've been testing the diode-resistor version manually and have the parts at home to build the microprocessor version. Another member designed an two-transistor circuit and Clive's last posting was adoption of a simple diode-resistor.

We don't get a lot of cold weather in Alabama but I continue to see more warm-weather MPG performance even with the temperatures drop to the 30s-40s. But it is a little tricky because if you enable it too soon, you can throw engine fault codes (not a good thing.) That is the 'work in progress,' determining what the set-enable temperature should be for the circuit.

Bob Wilson