Fuel Economy Auto Technology I Math / Science Integration
How do we measure Fuel Economy? • Fuel economy is calculated by the miles per gallon (mpg) or kilometers per liter (km/l) of fuel that a vehicle consumes. • The more distance per tank of fuel, the better the fuel economy. http://www.wisegeek.com/what-is-fuel-economy.htm
Why is there a difference between city mpg and highway mpg? • City mpg are lower because you stop and start more often than on highway. • Vehicles consume more fuel on 1st and 2nd gear, • The engine has to start moving, (~ 3500 pounds)… • with no momentum • more fuel needs to be used to produce power • the larger the combustion, the more power it will produce • On the highway, the vehicle is already moving at a less variable speed. • momentum again leads to the engine not having to produce as much torque to move the wheels. • Note: Torque is what make the wheels turn, not horsepower.
How can you find out about fuel economy when purchasing a vehicle? EPA and NHTA are seeking public comment regarding the new fuel economy labeling (2012).
How to Improve Fuel Efficiency • Properly Inflate the Tires!All tires have the recommended pressure listed right there on the sidewall. I mention the sidewall, because going by the door tag won't help you if you have custom-sized/over-sized tires. Having the right tire pressure not only improves MPG, it makes your vehicle safer on the road. Low pressure increases heat/friction which increases rolling resistance. This means that your vehicle has to use more gas to get there. • Close Those Windows!Driving with the windows closed, even while running the A/C, increased fuel mileage. With the windows open, especially at highway speeds, the buffeting wind increases the drag coefficient. If you don't have A/C, open the vent system to fresh air and run the fan, if you have to. (By the way, they also proved that driving with a Truck's tailgate up or down made no difference on MPG.) • Drive the Speed Limit!According to Government sponsored testing, every 5 miles over 60 MPH cost you an additional .24 cents per gallon (as of 2011). • Keep at a Half Tank Minimum!Did you know that driving until your tank is almost empty is a gas waster? As gas sloshes around in the tank, evaporation increases. Keep your tank at least half full. Besides, gas keeps your electric fuel pump running cool. It will overheat and malfunction, if you repeatedly wait until the gauge is on E before filling up.
How to Improve Fuel Efficiency (Cont’d) • Lighten your Load!If you have junk in the trunk, you are wasting gas! Your engine has to work harder to get that extra weight up to speed. And, your brakes work harder to stop it. • Change your Attitude Behind the Wheel! • Jack rabbit starts & stopping in short distances waste gas. Sitting at idle, you are getting 0 MPG! • Use Fuel Additives!Some Fuel Treatments can be mixed in both Gasoline and Diesel fuel, in both carbureted and injected engines. They clean the fuel system (including the injectors), while lubricating all moving parts. Micro-lubricants also help to remove carbon deposits from valves and the combustion chamber. (use this every 6 mos. or 6,000 miles, which ever comes first) The occasional bottle of Gumout or STP Fuel Treatment can help to improve fuel economy. • Tune Up!Change the spark plugs, cap & rotor, air and fuel filters. Many of today's newer vehicles have distributor-less ignition, meaning that there is no cap or rotor to replace. Computers monitor an array of sensors and make adjustments necessary to maintain a pre-set 14.7:1 fuel/air ratio. Faulty sensors waste gas! • Change your Oil Regularly!Whether it is Single weight, Multi-Viscosity, Mineral based, Blended or Pure Synthetic, changing your oil regularly does more to prolong the life of your engine than anything else can! Most recommendations include an oil change every 3-5,000 miles! A properly lubricated engine saves fuel! http://www.ehow.com/how_4854651_increase-fuel-economy.html#ixzz1DZfMDqsl