Angela asked about the expected fuel efficiency difference for a 300 ft uphill drive. I'm a dork and thought, hmmm...I wonder.
Turns out a gallon of gas has 125,000 BTUs of energy which is about 97,000,000 ft-lbs. Assuming a standard internal combustion engine efficiency of 20% (thanks Gary Smith), there is almost 20,000,000 ft-lbs of produced energy from the car.
Now, given my car's empty curb weight plus my 140 pound nerd frame we have to move 3000 pounds up 300 feet. Sounds like that is 900,000 ft-lbs or the equivalent of 0.046 gallons of gas.
Then, if my overall average gas mileage is about 49 mpg, I would use 1.22 gallons each way. However uphill would require 1.22+0.046 and back would be 1.22-0.046. That would have me expect to get 47.2 on the way to work and 50.9 on the way home.
So no. The difference is more than I would expect. And I'm still a dork.
5 comments:
My head hurts.
I think I'm going to feature you in a new play called "Dorktacular Dorktacular".
The next step is to determine HOW you drive to and from work, and how that might affect gas mileage. Do you drive faster/slower? Are there more slow downs/accelerations? How about air temperatures? Maybe you weigh more at the end of the day than in the morning. We must get to the bottom of this!
Melissa- if your head hurts image what it was like to be the mother trying to rationalize with or explain to this child ... (actually quite fun!!)
I knew you hung out in the "Control Room" more than you admitted. It is beginning to show...
*claps* Wow - that right there is an excellent blog entry. Way to show off your Geek skillz! What makes it even better is that I'm listening to Nerdcore HipHop...so your blog just made for a well rounded geek moment. Thanks!
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