What’s the difference between the different types of biodiesel? How can I tell which blend my car can take?
When Rudolf Diesel invented the original diesel engine in the 1890s, he designed it to run on a wide range of fuels — including vegetable oils. But in the early 1900s, diesel engines were adapted to burn mainly petrodiesel, a cheaper fuel. During the energy crisis of the 1970s, researchers began to reconsider vegetable oil fuels and found a simple method for turning vegetable oil into a usable diesel fuel.
These days, with “clean diesel” cars using sophisticated fuel injection and exhaust system pollution controls, it’s important to be more careful about the use of biodiesel because using it may void the vehicle’s factory warranty. But that doesn’t mean that biodiesel blends can’t be used safely.
Types of Biodiesel
Pure biodiesel is called B100. More commercially available biodiesel blends are B20 (20 percent biodiesel and 80 percent petroleum diesel) and B5 (5 percent biodiesel, 95 percent petroleum diesel).
All of the diesel cars currently offered in the United States come from German automakers. Fuel prices are considerably higher in Europe than they are in North America, so diesel cars are much more popular there because diesel cars are more fuel efficient than gas cars. In fact, more than half the cars sold in Europe now have diesel engines. Several Japanese automakers have diesel models in the works, but they are proceeding cautiously. Chevrolet has promised a diesel version of its high-mpg Cruze for 2013.
Diesel cars and SUVs from Volkswagen, Audi, BMW and Mercedes-Benz are all now approved to use B5 under warranty. Volkswagen was the first to allow B5 and the automaker currently is testing B20 blends. Always check the owner’s manual before using biodiesel to make sure doing so won’t void your warranty.
B20 is approved for use in heavy-duty diesel trucks. The most recent models with the Ford Power Stroke, GM Duramax and Dodge Cummins diesel engines all can run B20 biodiesel without warranty worries. 2011 Ford Super Duty pickups even have “B20” boldly displayed on the Power Stroke fender badge.
Even in relatively small blend percentages, the addition of biodiesel as an alternative fuel is a step in the right direction, reducing our dependence on foreign petroleum with a sustainable, domestic alternative.
— Todd Kaho, Editor and Publisher, Frugal Driver
Photo courtesy Audi