Biodiesel Mileage...
an Increase or Decrease?

A thought on biodiesel mileage: Since biodiesel has a slightly lower energy content that petrodiesel, a slight loss in mileage would only make since.

I find it interesting that some people have reported experiencing a slight increase in their fuel efficiency and am eager to learn more about this.

It is much more common for people to report experiencing a slight loss in mileage.

• Loss of biodiesel mileage can be caused by deposit build-up in the engine. A new test (as of 2008) has been developed

that represents the modern turbo-charged/ common-rail/ electronic/ direct-injection diesel engine.

This test can be used for researching injector build up.

• The use of detergent additives (used widely in Europe) can resolve combustion performance issues, and has the potential to fix power loss as well.

• Some modern direct injection engines that run at hotter temperatures have been reported to have problems with build-up.

• The older indirect injection engines, which run at lower temperatures, tend to receive benefits from the biodiesel's solvent and lubricating properties.


Energy Content:

• Biodiesel has a lower energy content than petrodiesel. According to the EPA, plant-based biodiesel averages 4.6% less energy per gallon, animal-based 10.6% less per gallon. That means if you multiply the percentage of a biodiesel blend by 4.6% (we'll use this because the majority of biodiesel is made from plant oils), it will equal the percentage of miles per gallon that will be lost.

• Figure this:

If you were using a B20 blend you would figure 20% X 4.6%.
So enter (0.20 X 0.046) on a calculator.
This gives you (0.0092).
Move the decimal point to the right two places, which gives you (0.92).
This means you can expect to see your mpg decrease 0.92%.

And if you were using a B5 blend, (5% X 4.6%) means you are decreasing your MPG by 0.23%.

B100? A decrease of 4.6%.


Considering Cost:

• The cost difference must be considered. If you are able to get biodiesel 5% cheaper than petrodiesel, you are likely traveling the same distance at the for the same cost.


Conclusion:

Considering that some injector build-up issues have been reported with the modern direct-injection engines, a bit of research may be on the plate for those purchasing vehicles.

If you have favorable reports of biodiesel mileage, please let me know about your experience and what you believe causes this. (Contact link coming soon.)

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