Who says racing has nothing to do with fuel economy? Honestly, I was rather shocked to hear about the prominence of hypermiling techniques in racing, especially NASCAR. Perhaps the revolution is hitting home with more people than the news would lead us to believe. Here’s the word direct from Earnhardt and ESPN:
Knowing the race was going to be extended beyond its scheduled 200 laps, Eury told Earnhardt to shut the engine off and coast whenever he could under the caution flag in a desperate effort to save more gas.
Junior did just that, coasting fast enough at times that he passed the pace car — until NASCAR warned Eury to have Earnhardt cut it out.
“I didn’t know how much they were going to worry about it,” Earnhardt said. “All the cars out there are gassing it, shutting ‘em off, coasting about a half straightaway, cranking ‘em back up, gas it, coast. Everybody’s doing it.
For those of you who don’t know already, this technique is oftentimes called “Pulse & Glide,” and is widely used by ecodrivers looking to get better gas mileage. P&G works by making your engine work only when it’s most efficient, and shutting it off at other times.
P&G, as the name suggests, has two main components. The pulse is an acceleration phase with lots of throttle, and the glide is a coast in neutral or with the engine off. People using P&G for fuel economy will often pick a median speed and pulse up to 10 MPH above that and then glide down to 10 MPH below, so that they can maintain an average speed around where the would be driving anyway.
It works because your engine is most efficient in high load operation, and then uses no fuel if you’re coasting with the engine off, as Earnhardt did. Rather than being in a constant low load, inefficient state, the combination of burning more during acceleration and then none during coast averages out to savings. While it may seem counter intuitive, Earnhardt’s victory clearly shows that it’s a viable technique.
Now, that said, I do not recommend using P&G in traffic where other drivers might not know what you’re doing or it might be dangerous. It’s best at low speeds (where aerodynamics is not so much of a factor) and when you have an open road that you know well. For a better description of P&G, see this MetroMPG.com article. For more fuel efficient driving techniques check out the 100+ EcoDriving Tips list.
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