Flexible Fuel Vehicles: The Engine

In the recent post of October 3^rd, we discussed the types of fuel that could be used in multiple-fuel engines. The Open Fuel Standard Act of 2009 (House Bill H.R. 1476) would require 80% of the cars manufactured or sold in the U.S. to be able to burn M85, E85 or Gasoline. The "85" refers to the percent of methanol or ethanol combined with 15% gasoline.

Today’s gasoline engines are made to run on gasoline with octane that ranges from 87 to 93 (87, 89, 91 & 93) on gas pumps in New England, where I live. Methanol has octane that ranges from 105 to 109 (Source: EPA, 2002 Clean Automotive Technology Program) and ethanol has octane ratings that range from 94 to 96 (Source: Renewable Fuels Association). This is much closer to gasoline’s octane ratings.

What does all of this mean? That a flex fuel engine is a compromise in efficiency.  Gasoline engines are built to have compression ratios of somewhere between 9 and 10 to 1 (9:1 to 10:1). Compression ratio means that the piston squeezes the air fuel mixture by a factor of 10, for example, between the intake of fuel and air and compressing it just before the spark plug ignites the fuel to provide power.

 Source: AutoZone Ref. Library

If you use a low octane fuel with a high compression engine, the fuel may combust before the spark plug ignites it. Mechanics call it “knock” and you can hear it when the engine is running because it sounds like popcorn in a microwave oven. Higher compression ratios mean higher pressures and temperatures and temperature drives efficiency in a heat engine, like a car engine.

If you have higher octane fuels like methanol (especially), the engine can operate at a higher compression ratio. A methanol engine can operate at an optimal compression ratio of 19.5:1 (ranging from 17:1 to 22:1 in EPA tests). This yields higher efficiencies than a gasoline engine.

A confession: In my upcoming book (Energy: The Primer, How to Distinguish a BTU from a BLT and Other Stuff You Should Know About Energy), I have a chapter entitled, "Methanol - The Other Motor Fuel." I like methanol better than ethanol as a gasoline substitute for a number of reasons: (1) Methanol can be made from plentiful coal, natural gas and ultimately carbon dioxide combined with hydrogen (when we run out of fossil fuels), (2) It could eliminate our reliance on imported crude oil,  (3) The higher octane rating will allow internal combustion engines to run more efficiently, (4) Methanol can run directly in fuel cells, ultimately displacing the less efficient internal combustion engine and (5) The world eats corn and it's the feedstock for ethanol. I would rather not have a motor fuel compete for use of a foodstuff as a feedstock.

Cloud (Celestial?) vs. Terrestrial Computing: The Energy Use

Amanda Mecke, my literary agent, pointed me in the direction of a very interesting article, How Energy Efficient is Cloud Computing? by Lisa Zyga (Oct. 8, 2010), about the energy used in cloud vs. desktop computing. The article cites an IEEE (The Institute for Electrical and Electronics Engineers) study that reverses the original thought that cloud computing is more energy efficient than desktop computing.

Not originally considered was the energy used in transporting the data from home or office computers, which is higher yet than what the servers consume in the data center. “While previous studies of energy consumption in cloud computing have focused only on the energy consumed in the data center, the researchers found that transporting data between data centers and home computers can consume even larger amounts of energy than storing it.”

And the data center can be in a different city, state or country, increasing the energy consumption for greater distances. Power consumption in the data centers alone is predicted to double from 2007 to 2020. “Specifically, power for transport can be as low as 10% and 25% at low usage levels for private and public storage services, respectively, and nearly 60% and 90%, respectively, at high usage levels.”

Does anyone find themselves sending fewer signals into the cloud from desktop computers, cell phones, blackberries, laptops, netbooks, iPads, etc. any less as life goes on? I don’t. I just ordered a Kindle with the nearly 10 inch screen and constant, global 3G connectedness. Did I give a first thought to the power it will consume for the years I will own it? Alas, nay. I wanted it. I bought it. I’ll use it. I need it. At some point, I’ll wonder how I ever led my Neanderthal-like existence without it. Like all of you, I’m more than willing to use the additional energy.

A note about personal experience: Since the first laptop was put on my desk (more decades ago than I care to divulge), I’ve always powered down before I left the office each night. Recently, my IT department (you know, the guys who think they’re protecting the system from me and you; and who I think should run the system to serve me and you!) directed us to never shut down our computers again.  Seems they want to be able to load software and do diagnostics from their “cloud” while we’re all sleeping on ours. More energy use without a first thought. Take a look at the article.