I'm with Arragonis here - I cruise at the posted speed limit on long flat stretches with traffic, but I also P&G with EOC when hills, stops, and traffic allow it.
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Originally Posted by hackish
If it were valid then why would the scientists who work on eco - competitions not do it?
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Because they build cars with small enough engines that they are operating near full throttle at steady-state cruise. Compare this to our daily drivers with engines sized for acceleration and "sportiness".
Also, it's not just "scientists" doing it -
NASCAR of all places has started using pulse & glide.
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Originally Posted by hackish
Why wouldn't hybrids do it too? I mean they could P&G with electric and fuel.
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I've had this thought before as well. It would be fun to test!
Just because something isn't available on the market, doesn't mean it's not a good idea.
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Originally Posted by hackish
An accelerating engine consumes more fuel per unit of energy produced.
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Most engines have the lowest BSFC near 80% throttle at low RPM. Of course acceleration enrichment varies by fuel system, but in a high gear the RPM rate of change is pretty slow.
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Originally Posted by hackish
Finally, P&G pollutes significantly more. Most vehicle emissions are tied to the cat temps. When you shut the engine off, the cat cools below it's effective range, restart it and for the next 20-30 seconds you will be sending somewhere around 5-10x the pollutants out the tailpipe.
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This is an interesting consideration that isn't discussed much around here, perhaps because we don't have emissions instrumentation on our dashboards. Does anybody have experience driving around with emissions instrumentation?