Just purchased a used 2007 Subaru Legacy 2.5i wagon. The display on the dash has the ability to display "instantaneous fuel consumption" and average fuel consumption, both in liters/100 km. The average fuel consumption reading is tied to the trip odometer, so that is where the calculation gets its total distance travelled. However, how does the calculation get total fuel consumed, given that the fuel consumption rate is a continuously changing variable? How accurate would these fuel consumption algorithm be?
Thx.