lyd -
The "alg"(orithm?) is from post
#10 above :
OBD 2007 - Installation Guide
http://www.glmsoftware.com/Documenta...de20080822.pdf - Page 15 of PDF
Quote:
fuel consumption can be calculated, if a vehicle supports Pid 0x0D Vehicle Speed and Pid 0x10 Mass Air Flow. All vehicles support vehicle speed and nearly all vehicles support MAF.
MAF, the mass of air moving into the engine is measured in grams per second. A petrol/gasoline engine burns the air/fuel mixture at the stoichiometric air fuel ratio of 14.64:1. The oxygen sensors in a modern vehicle are designed in conjunction with both the short and long term fuel trims to maintain this ratio. Under ideal conditions for every 14.64 grams of air an engine will consume 1 gram of petrol. We can therefore calculate FuelFlowGramsPersSec = MAF/Air Fuel ratio. We can convert the previous figure to FuelFlowLitresPerSecond by dividing FuelFlowGramsPerSec by the density of petrol/gasoline.
We can then readily convert that figure to FuelFlowLitresPerHour -- i.e. litres/hour. Fuel consumption is then simply SpeedKmsPerHour/FuelFlowLitresPerHours -- i.e. litres/kms.
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CarloSW2