Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Two alternative methods for measuring MPG in an old diesel.

UFO · 08-09-2013, 02:12 PM

The biggest challenge is measuring fuel flow. With a diesel you cannot infer fuel flow by measuring air flow, at least not accurately, because fuel mixture is varied unlike a gasser which needs closely held mixtures to prevent knocking and overfueling. That is why method one will give unreliable results, as it simply does what my Scangauge on my OBDII diesel does, infers fuel consumption based on airflow.

Method 2 may be your better option, but that will be vehicle specific based on turbo, injection method and injection pump type.

Honestly, I think the most direct solution may be a pair of high resolution flow meters, one on the supply, one on the return, and fuel consumption is the calculated difference.

08-09-2013, 02:12 PM	#2 (permalink)
UFO Master EcoModder Join Date: Sep 2010 Location: Denver, CO Posts: 1,300 Colorado - '17 Chevrolet Colorado 4x4 LT 90 day: 23.07 mpg (US) Thanks: 315 Thanked 179 Times in 138 Posts	The biggest challenge is measuring fuel flow. With a diesel you cannot infer fuel flow by measuring air flow, at least not accurately, because fuel mixture is varied unlike a gasser which needs closely held mixtures to prevent knocking and overfueling. That is why method one will give unreliable results, as it simply does what my Scangauge on my OBDII diesel does, infers fuel consumption based on airflow. Method 2 may be your better option, but that will be vehicle specific based on turbo, injection method and injection pump type. Honestly, I think the most direct solution may be a pair of high resolution flow meters, one on the supply, one on the return, and fuel consumption is the calculated difference. __________________ I'm not coasting, I'm shifting slowly.