View Single Post
Old 11-30-2011, 11:04 AM   #7 (permalink)
Master EcoModder
Diesel_Dave's Avatar
Join Date: May 2011
Location: Indiana
Posts: 1,194

White Whale - '07 Dodge Ram 2500 ST Quad Cab 2wd, short bed
Team Cummins
90 day: 37.68 mpg (US)
Thanks: 112
Thanked 502 Times in 211 Posts
Originally Posted by roosterk0031 View Post
Nice data, but which method nets the best MPG, higher load uses the least gas, but also goes the least distance, given the same glide afterwards, you would end up needing more pulses on a given trip.

Assuming the average speed of the pulse is 1/2 way between the begining speed and end speed of the pluse, x the time you could get distance covered, then using the fuel used figure out which is most efficient?

I think then you have to factor over a given distance say 20 miles as more P&G cycles of one method vs different number of P&G cycles at other accelration rates.
Yes, a slight correction is needed. What's needed is compute miles per gallon for 1 pulse and 1 glide. Assuming your pulse in linear then you'll cover 0.104 miles with 83% and 0.069 miles with 90%.

"True" FE for 83% would be (0.104 + X)/(0.005963+Y) where X is the number of miles in your glide and Y is the gallons of fuel in your glide. 90% FE would be (0.069 + X)/(0.004688+Y).

If EOC then Y=0. I ran the numbers for that. As long as your glide is >0.065 miles then 90% is better. That would most likely be true since your pulse distance is 0.069 miles, and I assume your glide distance is greater than your pulse distance. If your glide distance is 0.5 miles then the 90% gives you a 20% improvement relative to 83%

Nice test, BTW.
Diesel Dave

My version of energy storage is called "momentum".
My version of regenerative braking is called "bump starting".

1 Year Avg (Every Mile Traveled) = 47.8 mpg

BEST TANK: 2,009.6 mi on 35 gal (57.42 mpg):

  Reply With Quote