Veggie Across America: All Systems Go

Just days before departure, I had all the systems hooked up and ready to go on the roughly 2,500-mile journey from Atlanta to Los Angeles. In an earlier post, I described all of the systems and engineering necessary to convert the workaday 1982 Mercedes-Benz 300TD turbodiesel wagon from a petroleum burner to a purely vegetable oil-fueled ride. Below are pics of all those items installed, in suburban Atlanta the morning of our departure last Friday, December 5. Riding along with me and navigating us along Old U.S. 80 is my best college friend Hugh Dorsey.

1. Cooling System Tee
The primary source of heat to turn thick, cold vegetable oil into thin, hot fuel is antifreeze from the radiator. Using a plastic three-way Tee from NAPA auto parts, one simply taps into this line coming from the heater core and going to the cylinder head.

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2. 16-plate Heat Exchanger
The lower right line you see in the picture above is the one that came from the cooling system Tee. It flows hot radiator fluid through this 16-plate bronzed copper heat exchanger. Notice the smaller lines on the left side, both lower and upper? Those carry cold vegetable oil from the tank, which flows from bottom to top through a labyrinth of tiny tubes (like a radiator) that are heated by antifreeze from the radiator. This is the first point of heat for the cold vegetable oil.

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3. Heat Exchanger / Vegetable Oil Filter
Engine coolant (radiator antifreeze) must flow through another heat exchanger before its trip back to the radiator. The heat exchanger above is combined with a filter. The entire device above both filters the vegetable oil to remove impurities and particles, as well as heating it another time to bring it up to high temperatures. Notice the smaller lines at the bottom of the device? These flow once-heated vegetable oil out of the 16-plate heat exchanger, send it through a heat exchanger warmed by engine coolant for a second heating, send it through the orange Baldwin 4-micron oil filter, and then back out and onto the mechanical fuel pump. The coolant has now done its oil heating duties and is ready for return to the car's cooling system.

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4. Return Cooling System Tee
Having been re-routed through two heat exchangers, the hot coolant flows across the engine bay to another NAPA 3-way Tee and re-enters the car's engine cooling system.

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5. Dash Toggle Switch
When starting on a cold morning, the car's radiator is, naturally, also cold. How to warm the system up while the vegetable oil is too cold to burn? Flip this toggle switch that powers two fuel selector valves that route diesel fuel from a small tank to get things going.

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6. Fuel Selector Valve
The fuel selector valve, above, and another one just below it, always flow out the left port, but alternate between the right upper and lower ports for flow into the valve depending upon whether the dash toggle switch is on or off. The upper valves connect to the vegetable oil system going to the car's main fuel tank where vegetable oil is stored. The lower valves go to the purge tank, a small one-gallon tank located in the left fender well filled with diesel #2 for startup and shutdown purposes only.

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7. Purge Tank
When the dash toggle switch is turned to the on position, fuel is both drawn from and returned to this one-gallon purge tank located in the left fender well. This allows the engine to start, heat up, and gradually send hot antifreeze through the heat exchangers, warming up the thick vegetable oil the point where it can be used as fuel for the engine. The purge tank is also employed a few minutes before shutting off the engine at the close of the day in order to clear all fuel lines and the fuel pump of any remaining vegetable oil that could thicken in the lines and injectors overnight.

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1982 Mercedes-Benz 300TDEnlarge PhotoJust days before departure, I had all the systems hooked up and ready to go on the roughly 2,500-mile journey from Atlanta to Los Angeles. In an earlier post, I described all of the systems and engineering necessary to convert the workaday 1982 Mercedes-Benz 300TD turbodiesel wagon from a petroleum burner to a purely vegetable oil-fueled ride. Below are pics of all those items installed, in suburban Atlanta the morning of our departure last Friday, December 5. Riding along with me and navigating us along Old U.S. 80 is my best college friend Hugh Dorsey. cooling system TeeEnlarge Photo 1. Cooling System Tee The primary source of heat to turn thick, cold vegetable oil into thin, hot fuel is antifreeze from the radiator. Using a plastic three-way Tee from NAPA auto parts, one simply taps into this line coming from the heater core and going to the cylinder head. --- 16-plate heat exchangerEnlarge Photo 2. 16-plate Heat Exchanger The lower right line you see in the picture above is the one that came from the cooling system Tee. It flows hot radiator fluid through this 16-plate bronzed copper heat exchanger. Notice the smaller lines on the left side, both lower and upper? Those carry cold vegetable oil from the tank, which flows from bottom to top through a labyrinth of tiny tubes (like a radiator) that are heated by antifreeze from the radiator. This is the first point of heat for the cold vegetable oil. --- 4 micron filter + heat exchangerEnlarge Photo 3. Heat Exchanger / Vegetable Oil Filter Engine coolant (radiator antifreeze) must flow through another heat exchanger before its trip back to the radiator. The heat exchanger above is combined with a filter. The entire device above both filters the vegetable oil to remove impurities and particles, as well as heating it another time to bring it up to high temperatures. Notice the smaller lines at the bottom of the device? These flow once-heated vegetable oil out of the 16-plate heat exchanger, send it through a heat exchanger warmed by engine coolant for a second heating, send it through the orange Baldwin 4-micron oil filter, and then back out and onto the mechanical fuel pump. The coolant has now done its oil heating duties and is ready for return to the car's cooling system. --- cooling system TeeEnlarge Photo 4. Return Cooling System Tee Having been re-routed through two heat exchangers, the hot coolant flows across the engine bay to another NAPA 3-way Tee and re-enters the car's engine cooling system. --- toggle switchEnlarge Photo 5. Dash Toggle Switch When starting on a cold morning, the car's radiator is, naturally, also cold. How to warm the system up while the vegetable oil is too cold to burn? Flip this toggle switch that powers two fuel selector valves that route diesel fuel from a small tank to get things going. --- Enlarge Photo 6. Fuel Selector Valve The fuel selector valve, above, and another one just below it, always flow out the left port, but alternate between the right upper and lower ports for flow into the valve depending upon whether the dash toggle switch is on or off. The upper valves connect to the vegetable oil system going to the car's main fuel tank where vegetable oil is stored. The lower valves go to the purge tank, a small one-gallon tank located in the left fender well filled with diesel #2 for startup and shutdown purposes only. --- purge tankEnlarge Photo 7. Purge Tank When the dash toggle switch is turned to the on position, fuel is both drawn from and returned to this one-gallon purge tank located in the left fender well. This allows the engine to start, heat up, and gradually send hot antifreeze through the heat exchangers, warming up the thick vegetable oil the point where it can be used as fuel for the engine. The purge tank is also employed a few minutes before shutting off the engine at the close of the day in order to clear all fuel lines and the fuel pump of any remaining vegetable oil that could thicken in the lines and injectors overnight. --- auxiliary fuel pumpEnlarge Photo 8. Auxiliary Fuel Pump How to pump thick, cold, slow moving vegetable oil from the fuel tank up to the heat exchangers underhood? Use a 12-volt auxiliary fuel pump. It is located before the heat exchangers and the engine, and it boosts fuel pressure especially on cold mornings so that the engine is not starved of fuel once the selector valve is switched to the main fuel tank containing waste vegetable oil. --- injection line heatersEnlarge Photo 9. Injector Line Heater Some would call this system overkill, but heat is your friend when it comes to trying to inject vegetable oil into a diesel engine. Therefore, the veggie oil is heated for a third and final time by this electric injector line heater wrapped around the injection lines that go from the mechanical engine fuel pump up to the fuel injectors and on into the engine. This heater is powered by the car's battery and warms up to around 220 degrees Fahrenheit whenever the car's ignition is in the on position. --- oil storage containersEnlarge Photo 10. In-car Fuel Storage How to get from Atlanta to Los Angeles without using gas stations? Take your vegetable oil with you. The '82 Benz started off the journey transporting six 15-gallon plastic containers plus a full 17-gallon fuel tank of vegetable oil for a total of about 107 gallons of pure waste vegetable oil. Well, almost no gas stations; we have done a daily evening stop for a refuel of the purge tank, usually about .80 gallons of diesel #2. Averaging around $2 per day, that's a fuel cost we're happy to live with. --- oil storage containersEnlarge Photo 11. More In-car Fuel Storage Rather than locating all of the 15-gallon tanks in the rear of the Benz, where leverage weighs down the rear suspension more and causes ponderous handling, we put two of the tanks in the rear seats. They are belted in so that a panic stop won't send 110 pounds careening into the backs of our heads. --- And that's pretty much it. Not pictured is our refueling system, which consists of a five-gallon plastic bucket and a big funnel. Because the 15-gallon tanks are heavy and unwieldy, we first pour five gallons into a manageable plastic bucket. Then we dump the contents of the bucket through the large funnel and right into the Benz's gas tank. We do that twice more to empty the 15-gallon container and fill the tank, all the while idling the car and warming it up on the purge tank. Clean up, hop in, make sure the temperature gauge is about mid-point, and flip the toggle switch. Boom--instant vegetable oil operation. The only thing you notice is that the idle of the normally shaky, clattery diesel smoothes out a bit. Period. Also, there is no more smoke out the tailpipe, as vegetable oil burns cleaner than does diesel #2. Put it in drive, and you're on your way.--Colin Mathews --- Make sure you check out our partner sites dedicated to focused news, reviews and more for Ford, Chevrolet, Toyota, Honda, and the Toyota Prius.