Last week, I touched on some of the strategies coming out of the “hypermiling” movement to boost automobile fuel economy. Here are a few more:
1. Lighten the load. The more weight we haul around in our cars or trucks, the more energy we use. If you keep sandbags in the bed of your pick-up for winter traction, remove them in the summer. Empty your trunk of those unneeded items you’ve been hauling around.
2. Use air conditioning only when absolutely necessary. In some cars, running the A/C on max reduces mileage by as much as 25%. Around town, open a window. At highway speeds, it’s usually better to keep windows closed to reduce aerodynamic drag. If the fan alone doesn’t provide enough cooling, this is when the A/C makes sense.
3. Keep your vehicle tuned up. A smoother-running car or truck usually operates more efficiently–and lasts longer. If your owner’s manual provides a range of engine oil that can be used in your car, opt for the lower-viscosity grades (lower SAE number) to improve fuel economy.
4. Keep tires inflated. The higher the tire pressure, the lower the rolling resistance and the better the mileage. For most tires, manufacturers list a recommended pressure range (for example 32 to 40 psi when the tires are cool). To improve fuel economy, keep tire pressure closer to the top end of that range. Don’t overinflate tires, though, as this may compromise safety.
5. Avoid idling. If the engine is running and you’re standing still, your fuel economy is zero–and an idling engine usually spews out more pollution than an engine that’s running at higher speeds. Several towns in our area now have no-idling resolutions in an effort to discourage the practice.
6. Practice “rabbit timing.” Wayne Gerdes, who coined the term “hypermiling” and who maintains the CleanMPG website, explains this as a strategy that works for roadways with traffic lights that are tripped by sensors in the pavement. If you’re approaching a traffic light that’s red, ease off on your accelerator and let the cars around you (the “rabbits”) speed ahead and stop at the light, tripping the sensor–so that it turns green by the time you roll up.
7. Turn off cruise control on hilly terrain. Cruise control is designed to maintain constant speed, but in hilly terrain a lot of extra fuel is used in accelerating up hills. A more fuel-efficient approach is to hold the accelerator pedal in approximately the same position approaching and going over a hill; your speed will drop but fuel economy will be better. On the downhill, allow your speed to increase (within the speed limit), using gravity to boost your fuel economy.
8. Choose your route carefully. If you have two choices in getting from point A to point B, with one route being up-and-over while the other is around, the option with less hill-climbing will improve fuel economy. This is a place where I may part ways with the hypermilers. If the goal is highest fuel economy (miles per gallon), driving extra miles is okay. But my priority is lowest total fuel use. If you have two route options, and one is 100 miles over hilly terrain that results in 30 mpg while the other is 150 miles but on flatter roads resulting in 40 mpg, the first option will use less total fuel (3.3 gallons vs. 3.75), but the fuel economy with the second option would be a lot better. I’d rather take a more direct route and decrease my total fuel use, while the hypermiler would take the longer route to improve his or her fuel economy.
There are lots of other fuel-efficient driving tips on the CleanMPG website. But the best choice of all is to drive less. Consider walking or carpooling. If you bike to work in good weather, as I do, keep track of your commuting miles with a bike odometer, set some goals, and calculate your savings. I’ve biked over 500 commuting miles so far this year–which is already more than my total for last year!
In addition to this Energy Solutions blog, Alex writes the weekly blog on BuildingGreen.com: Alex’s Cool Product of the Week, which profiles an interesting new green building product each week. You can sign up to receive notices of these blogs by e-mail—enter your e-mail address in the upper right corner of any blog page.