Calibrating the 2010 Power Bar (ECO mode)
 

Hi,

Last night was too overcast to watch the meteor show so I took a couple of runs up Brindley Mountain with our Garmin GPS to get more hybrid system indicator (HSI) energy display data. In particular, I wanted to check the 75% and 100%, Eco band points:

http://hiwaay.net/~bzwilson/prius/pri_2010_710.jpg

NOTE: the clear cover causes a parallax error from the 8", cell phone camera. From the driver's head position, the yellow electrician tape markers look right.

I ran two climbs holding either 100% of the Eco bar or 75% and got these results:

http://hiwaay.net/~bzwilson/prius/pri_2010_790.jpg

The 100% Eco mode, 23.4 hp, came pretty close to my earlier, flat-land acceleration test. The 75% level was off, 15.3 vs. 12.8 hp, but I knew my earlier acceleration tests were somewhat dependent upon a few samples over a short interval. I have good confidence in the 15.3 value.

I have the data in a spreadsheet if there is any interest in seeing how I did
it.

Because this was a new procedure, I failed to record the fuel consumption rate. I'll have to go back and repeat it. However, at 100% of Eco bar, the car went up at an average of 35 mph (56 kph) but only 25 mph (40 kph) at 75%. The posted speed limit is 65 mph (104 kph) so it needs to be done when there is little traffic about and with the safety blinkers flashing. I am very uneasy about trying 50%, Eco bar power.

Bob Wilson

I was able to go back and this time record mileage. At 2:00 AM, I was able to run a 50% power run too:

power miles MPG mph
100% 1.5 23.8 35
_75% 1.5 25.3 26
_50% 1.5 22.2 16

On the descents, I simply put the car in "B" and let gravity and the spinning engine do the rest. But I noticed the battery fully charged and the top bar, slightly pink, was illuminated.

I returned to my starting point, about a mile away from the base of the hill and the battery was still fully charged. On the second run, the battery charge still showed full as I approached the base of the hill. I suspect this is why the middle run showed exceptionally high mileage, a battery boost.

For the last run, I used "EV" mode to bring the battery out of the 'pink bar,' full charge and then used regular "D" to approach the hill. Until there is a standard way to normalize the battery charge, I won't be able to trust this data.

To handle the battery energy contribution, we need to measure the traction battery current. Then comes the challenge of trying to use the charge/discharge energy flow to compensate for the altitude and distance.

Bob Wilson