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Old 12-13-2009, 08:40 PM   #3 (permalink)
Engineering first
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Join Date: Mar 2009
Location: Huntsville, AL
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Originally Posted by orange4boy View Post
. . .
There's a new "study" out by Tim Hortons claiming that drive throughs are less polluting than park and serve restaurants. Another sloppy bit of work that is very misleading. Have you seen it?

Thread here:
Thanks! I took a quick read and have a suggestion for an NHW11 experiment you might want to replicate while the engine is still warming up:
  • stop in "D" - monitor 30 seconds of idle fuel burn
  • stop in "N" - monitor 30 second of idle fuel burn
  • stop, turn off engine, restart 30 seconds - monitor fuel burn
Before I started cutting through my neighborhood to let the ICE warm up to 70 C, I had a shorter distance, less than 0.5 km, to a traffic light. That was where I learned sitting in "N" while waiting for a light change minimized fuel burn. I tried stopping the engine and waiting but the 'manual' engine startup was pretty wasteful of gas. If the car is in hybrid mode (Stage-4,) the engine start is 'free' but manually startup seems to invoke different control laws and burns more fuel than I think it should.

As for ordinary gas cars, all bets are off. We only have one on our driveway and ... I need to make sure it still runs one of these days.

Bob Wilson
2019 Std. Range Plus Model 3 - 134 MPG3 || 2014 BMW i3-REx - 117 MPGe, 39 MPG
JuiceBox 40 Pro (240 VAC, 40 A), KHONS portable (120-240 VAC, 12-32 A)
Retired engineer, Huntsville, AL (five times AutoPilot saved.)
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