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Old 02-07-2011, 08:25 AM   #68 (permalink)
bwilson4web
Engineering first
 
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Join Date: Mar 2009
Location: Huntsville, AL
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17 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

Blue Bob's - '19 Tesla Std Rng Plus
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Quote:
Originally Posted by Piwoslaw View Post
. . .
Idle consumption looks OK, Euromodder and I both have the same engine (1.6HDi) and we both see idle consumption around 0.5 l/h.
. . .
Interesting, tricking the 1.5L Prius engine to run in idle and compared to a 1.5L Echo, we got these numbers:
  • 0.64 l/h - 1.5L Prius (2003), 0.17 g/hr ScanGauge II
  • 0.57 l/h - 1.5L Echo (2001), 0.15 g/hr ScanGauge II
  • 0.23 l/h - 1.5L Prius in hybrid power/cyling idle, using differential MPG over 12 hours, built-in tripmeter with MPG display.
The first two were read by the Scangauge from the respective vehicles. The Prius engine was triggered to run by enabling the air conditioner, shifting into "N", and turning the air conditioner off. The last was measured by measuring fuel burned over a 12.7 hour period and calculating the fuel burn by comparing the MPG at the start and end. FYI, I'm reasonably confident of the accuracy.

Idle fuel burn is an indicator of the engine internal overhead. Simply take whatever thermodynamic ratio one wants to use against the fuel energy content and one would have a 'close enough' estimate of engine, mechanical overhead.

FYI, here is a chart showing Prius hybrid idle behavior of the main, 272V traction battery without and with a 1 kW load on the electrical system:

The 1 kW load was a space heater and we were drawing 13.75 V @71-74A.

Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL

Last edited by bwilson4web; 02-07-2011 at 08:51 AM..
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