Sterling Performance works around the clock 365 days a year testing parts, components and complicated tests for the automotive industry OEM and aftermarket. So many of the test are very complicated, but necessary in today’s world of strict guidelines. But, on a more simpler topic, do you know how fuel economy and mpg is calculated?
Fuel economy is measured under controlled conditions in a laboratory using a series of tests specified by federal law. Manufacturers test their own vehicles—usually pre-production prototypes—and report the results to EPA. EPA reviews the results and confirms about 15%–20% of them through their own tests at the National Vehicles and Fuel Emissions Laboratory.
Measuring Fuel Use
For vehicles using carbon-based fuels (e.g., gasoline, diesel, natural gas, etc.), a hose is connected to the tailpipe to collect the engine exhaust during the tests.The carbon in the exhaust is measured to calculate the amount of fuel burned during the test. This is more accurate than using a fuel gauge.A different method is used for vehicles that run on non-carbon fuels, such as fuel cell vehicles and electric vehicles.