Joe Connor's 1984 Mercedes 300D turbo diesel is a two-tank system. The car's traditional, diesel tank is pumped with biodiesel, a cleaner burning diesel (at start up, shut down and sometimes in-between, and when biodiesel is not available, running on regular diesel). The second tank, located in the spare tire well, runs on used vegetable oil.

 

 

What's the difference between biodiesel and used vegetable oil as automotive fuels? Here you go:

 

 

In a nutshell, Biodiesel is chemically altered to behave almost entirely like diesel, and can simply be pumped into Joe's diesel/traditional fuel tank with little to no modification required. Some exceptions are older model diesels that may require the replacement of rubber hoses and gaskets as biodiesel has a tendency to degrade rubber. Other minor adjustments could include replacement of fuel filters as when biodiesel is first used an increase in deposits within the engine system may occur.

 

 

Biodiesel is non-toxic and biodegradable, less toxic than table salt and biodegrades as fast as sugar. And unlike fossil fuels, biodiesel is renewable and can be made domestically, like in the U.S. Biodiesel may be blended with conventional diesel to get different blends such as B2 (2% biodiesel and 98% conventional diesel) or B20 (20% biodiesel) or it can be used as 100% biodiesel (B100).

 

 

Bottom line: Using used vegetable oil as automotive fuel - also known as that grease from the fryer - requires conversion because you don't want to pour bacon bits into your diesel/biodiesel tank, kiddo! Not only does used vegetable oil have to be filtered, it also congeals in cold temperatures, which is a nice way of saying you don't want to start your car on used vegetable oil in the cold!

 

 

Joe's Mercedes, aka "The Lime Green Renewable Energy Machine," is a two-tank fuel system. He uses primarily biodiesel (but occasionally diesel) at start up. Biodiesel is a cleaner form of diesel that is about the same cost in many parts of the U.S. as diesel, and can be used as fuel in any diesel engine car with little to no modifications.

 

Once the car is started, radiator fluid transfers heat from the engine to the heat exchangers in the fuel system. These exchangers heat the vegetable oil in the fuel filter, lines and fuel tank (The 13-gallon second tank is located in Joe's trunk in the spare tire well). The heat reduces the viscosity of vegetable oil so that it is similar to biodiesel or diesel, and can be injected into the engine properly. Joe simply presses a switch to run on vegetable oil once the car’s temperature is between 80-100 degrees.

 

When the engine is shut down for several hours, Joe switches back to biodiesel or diesel so remaining “cold” vegetable oil doesn’t clog up the injectors the next time the engine is started.

 

HOW MUCH USED VEGETABLE OIL IS OUT THERE?

Hotels and restaurants in the U.S. generate approximately 3 billion gallons of waste cooking oil per year. This amount could fill tanker trucks arranged bumper-to-bumper from San Francisco, California to Washington D.C. and back! Whoa Nellie!

 

What often happens to used cooking oil? Most restaurants pay a hauler to collect their used vegetable oil. A member of the kitchen staff dumps the used vegetable oil in a grease trap at the back of the restaurant. The hauler then picks up and transfers the grease, and it can be used to supplement feed for farms, but some of it can end up in a landfill, or worse! Where grease traps are not mandated and/or enforced by authorities, restaurants could potentially dump their used cooking oil down the drain where it can cause build-up and blockage in municipal sewer pipes. Yikes!

Both fuels are: renewable and cleaner than regular diesel or gasoline

Joe get his Biodiesel at: regular gas/petroleum/diesel stations, with the pump usually labeled "Biodiesel" or "B20," etc.

Joe gets used vegetable oil from: restaurants, co-ops or private individuals

Mileage performance: About the same, no matter which fuel is running (low to mid 20s in the city; mid to high 20s on the highway)

Joe's exhaust often smells like: French fries! Yummy!

Joe has a unique, multiple filtration system inside his trunk, aka "The Grease Trap." Since most folks aren't as mobile as Joe, the typical filtration system is set up in a garage (as seen in the photos below). Here's how Joe's mobile filtration system works:

 

1. A hose line is dunked into a bucket of used vegetable oil, and a pump running off the car's battery, is turned on (the car is also turned on, so as not to drain the battery). The used vegetable oil flows through clear tubing through an initial, 500-micron sock filter and then into a 12.5 gallon red "holding tank" (not to be confused with the actual vegetable oil fuel tank). The clear tubing allows Joe the ability to see the color of the used vegetable oil flowing through the tubing (e.g., if the color is white, that likely means water or other contaminates are in the bucket of used vegetable oil, which is not good). Usually, any particulate matter or minor water contamination that wasn't picked up by the initial filter will flow to the bottom of the red "holding tank" over time (but not always). Joe only completes this No. 1 process when the car is good and hot. That's because used vegetable oil congeals at colder temperatures.

 

2. When Joe is ready to push used vegetable oil from the red holding tank into his actual vegetable oil fuel tank, he presses a switch that turns on a second, separate pump (Joe also has the car running at this time, so as not to drain the battery). The used vegetable oil flows from the red holding tank through clear tubing through a second, 20-micron sock filter before it makes its way into the actual vegetable oil fuel tank. Again, the benefit of the clear tubing is that Joe can clearly see the color and contents of the used vegetable oil flowing (e.g., if the color is bad and/or there are particles in the lines, Joe can turn off the pump immediately, unscrew some of the lines and ensure nothing harmful gets into the actual vegetable oil fuel tank). Step No. 2 in the process is also equipped with a special valve that allows Joe to shut down the entire system should there be a leak or other problem.

 

The most important aspect of running a car on used vegetable oil, and ensuring good mileage performance, is making sure the vegetable oil has been properly filtered and cleaned. This was a lesson Joe learned during The 2006 Tour, his inaugural year running his car on filtered used vegetable oil. Joe's current filtration system has worked effectively for the most part, with the clear tubing especially beneficial when Joe comes across a bucket of used vegetable oil that may not be best suited for fuel consumption (e.g., water or other contaminates mixed in). While not perfect (is there anything in life that is?), for the mobile environment, this filtration system is about as good as Joe and his collective veggie oil driving freakhead friends have been able to come up with!

 

The filtration system was designed and built in San Diego by two vegetable oil driving veterans, Brad and Isaac. Another San Diego friend of Joe's, Marco, helped select and install the diesel-style fuel pump that pushes used vegetable oil from the red holding tank through the final filter before it goes into the actual vegetable oil fuel tank. Thanks guys!