Set Cruise Control During Decel !?
 

On a CR-Z forum, one user is claiming that he gets ~50 mpg on his commute loop when he sets his cruise control during deceleration. Process is accel to 62 mph, decel, set cruise at 60 mph. If instead he accelerates to 60, holds steady at 60 and then sets the cruise, he'll get ~46-47 mpg.

Anybody experienced this? Any explanation?

No explanation for it, but I also get better results if I engage the CC while decelerating, and/or use the - button on the CC to set it.
- doesn't always set the current speed though, as it often reverts to a previous lower value.
When using the + to set the CC, I tap the - once or twice shortly after and let it settle at a better fuel economy.


I even did this before I had CC installed:
Accelerate a few kph above the target speed, then slightly let off the gas to settle at the target speed but at a better fuel economy..

I never noticed a difference in my cars. Once I engage CC, there is a drop off in fuel usage followed by a spike in fuel usage. The fuel usage then stabilizes once the speed stabilizes. I'm wondering if there are factors involved that your friend doesn't realize (slopes, difference in speeds, air currents, etc.)...

I set by rpm. On flat ground. Depending on vehicle driven may re-adjust to get it nailed down.

I think the de-cel/downhill thing is a bit of confusion occurring. A digital tachometer would reveal most of what is happening.