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Old 08-09-2013, 03:04 PM   #1 (permalink)
oldbeaver
EcoModding Apprentice
 
Join Date: Oct 2008
Location: Chile
Posts: 223

Mercedes 89 D - '89 Mercedes 300 E
90 day: 33.86 mpg (US)

Skodie - '09 Skoda Octavia TDI PD
90 day: 38.84 mpg (US)

1993 Mercedes 300D Turbo - '93 Mercedes Benz 300D Turbo W124
90 day: 26.19 mpg (US)

Crossie - '16 Subaru XV Crosstreak
90 day: 9.61 mpg (US)

Crossie - '16 Subaru XV Crosstreak
90 day: 33.34 mpg (US)
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Two alternative methods for measuring MPG in an old diesel.

Dear fellow experimenters,

There are two possible alternative methods to determine fuel consumption in a non OBDII diesel vehicle.

I would call this methods as

1) the VSS - MAF method.

2) The GPS - aerodynamics method.


1) The VSS - MAF method.

It works as follows:

MPG = VSS / MAF * 7.718 for gasoline engines.

The constant is the result of units conversions (14.7 kg of air per kg of fuel).

See his complete paper here:

http://www.windmill.co.uk/obdii.pdf

Why cannot we use the same idea to estimate fuel consumption in a diesel?

He also presents an electronic circuit which is relatively simple and cheap.


2) The GPS - Aerodynamics method:

This method uses no connection to car sensors. It just uses a GPS to determine horizontal speed and vertical speed, as well as real km.

For determine the fuel consumption, it uses the aerodynamics and weight od the car, as well as the power of the engine. This method is used in an Android application called "Digifuel". This application is already available for gasoline engines. Equations are needed for diesel engines.

The idea is to input the characteristics of each particular car and the rest is done by the GPS.

Both methods need a display to show results in real time, as well as a processor circuit for calculations.

Any comments?

OldBeaver

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Mercedes 300 D turbo 1993
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