Optimizing Automobile Mileage. (A gallon of gas produces 20 pounds of carbon dioxide.)

Dear S and B,

At the moment, I am reading the NC State Driving Manual (in anticipation of taking the DMV test to re-new my license).

Here are some interesting facts.

Don’t be a jackrabbit. Abrupt starts and hard stops can increase fuel consumption by 40%.  (I have always know that "jack-rabbiting" consumes a significant amount of gas. The 40% figure is an eye-opener.)

Slow down and save. Every five miles over 60 mph can cost you up to an additional 30 cents a gallon. 

Don’t drip and drive. Tightening your fuel cap can prevent leakage of up to 30 gallons of gas a year.

Let your car breathe. Clogged air filters can cut mileage by 10%.

There is some variability in the relationship between speed mileage, in part due to engine design. The following information from the European Environment Agency shows that decreasing highway speed from 72 mph to 66 mph results in 12% to 15% gas savings. http://www.eea.europa.eu/themes/transport/speed-limits

Check tire pressure once a month and keep tires properly inflated. Properly inflated tires can reduce gas consumption by 3.3%.  http://www.fueleconomy.gov/feg/maintain.shtml 

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Astonishing as it sounds, every gallon of combusted gasoline creates 20 pounds of carbon dioxide gas. 

Imagine a pound of gas. Then multiply by 20!

Here is the chemical equation: http://www.fueleconomy.gov/feg/co2.shtml

It seems impossible that a gallon of gasoline, which weighs about 6.3 pounds, could produce 20 pounds of carbon dioxide (CO2) when burned. However, most of the weight of the CO2 doesn't come from the gasoline itself, but the oxygen in the air.

When gasoline burns, the carbon and hydrogen separate. The hydrogen combines with oxygen to form water (H2O), and carbon combines with oxygen to form carbon dioxide (CO2).

A carbon atom has a weight of 12, and each oxygen atom has a weight of 16, giving each single molecule of CO2 an atomic weight of 44 (12 from carbon and 32 from oxygen).

Therefore, to calculate the amount of CO2 produced from a gallon of gasoline, the weight of the carbon in the gasoline is multiplied by 44/12 or 3.7.

Since gasoline is about 87% carbon and 13% hydrogen by weight, the carbon in a gallon of gasoline weighs 5.5 pounds (6.3 lbs. x .87).

We can then multiply the weight of the carbon (5.5 pounds) by 3.7, which equals 20 pounds of CO2!

Love

Daddy man