# How to calculate accurate fuel consumption for Diesel engine by using OBD data? [duplicate]

Can you recommend formula for calculating fuel consumption using OBD data for diesel engine? I find a article(http://www.windmill.co.uk/obdii.pdf) about fuel calculation using vehicle speed and MAF(mass air flow), but I am not sure the formula described in that article is applicable for Diesel engine. Any accurate formula for Diesel engine will be highly appreciated.

• There are several relevant questions and answers on here, you should read this : mechanics.stackexchange.com/q/63098/10976 and this one : mechanics.stackexchange.com/q/27882/10976 Mar 20, 2019 at 7:17
• You may also need stoichiometric combustion is 14.7 for gasoline and 14.5 for diesel... Check though.. Mar 20, 2019 at 7:23
• @SolarMike Thanks. Is this formula for fuel flow rate is correct? fuelFlow = ((MAF * 3600) / (14.7f * 820)) / 10 ; // l/h Mar 21, 2019 at 0:40
• The problem is that a diesel may run 5-80 A/F, and stoichiometric combustion is only an ideal. It will be useless to assume 14.5 in the calculation, as the actual operating point will vary wildly and spend little time at stochiometric. This has been asked before, and the response rate of OBD II data is probably not going to yield good results on anything but a long-term analysis. Diesel, gasoline, or otherwise. Mar 22, 2019 at 3:35