Here's a closeup of the valves and solenoid.
While driving Woolf's vehicles, we checked out the changeover to veggie oil firsthand, and the transition is smooth and seamless. Simply flip a switch on the dash, and in a minute or so, the performance is noticeably quieter, while the acceleration feels virtually identical. In addition, the soot and stink are markedly reduced. Can you imagine a diesel that actually smells good and runs better? And on free fuel? Of course, as with all new-fangled inventions, there are a few complications and downsides. One of them involves shutting off the vegetable oil and purging the fuel system with conventional diesel fuel. This step is required before turning off the engine for any length of time, in order to prevent cooled vegetable oil from clogging the fuel system-although, probably not necessary for short stops of an hour or so, depending on the ambient air temperature.
There is a separate filler neck for a vegetable oil tank.
The length of time to purge the system is not precise, but you can hear the change in engine sound. Woolf advises switching back to diesel for a minimum of 3 to 5 minutes (or a mile or two from your destination). The solenoids and valves that handle the changeover are similar to what you'd have with an auxiliary tank containing conventional diesel fuel, so this technology is nothing new. Another potential downside is the hassle of filtering used vegetable oil by hand, but Woolf has a solution for that. In the early days of the veggie oil movement, recycled oil was laboriously poured by hand through a large, sock-shaped filter, which can take hours and leave a mess of dirty buckets of used oil. Instead, Woolf has invented an onboard filtration system that costs about $500. It has two or more filters that step from 14 down to 4 microns, essential for the new common-rail fuel systems with higher injection pressures.
Here's a look at the auxiliary tank for Woolf's Dodge Ram.
To demonstrate the system, Woolf pulled up behind a local restaurant, after calling the chef for permission beforehand, and stuck one end of the hose into a barrel at the back door. Woolf turned on a battery-powered electric pump that sucked up the fuel, and he fed it through the filters and into the auxiliary tank. Later on, he plans to add an automatic reel under the bed to retract and store the hose. The whole process took no longer than filling up at a regular fuel station, with one big difference-he didn't have to pay for the oil. In fact, the owner of the restaurant actually asked Woolf to return within the next week to pick up some more used oil.
The size of the tank on your vehicle can vary, but a typical full-width toolbox found in the bed of a pickup can hold a 50- to 100-gallon tank (mileage is roughly the same, depending on the type of fuel system). As most Diesel Power readers already know, diesels are great for hauling heavy loads, so you'd hardly know all that veggie oil was in the bed. Passenger cars are a bit more of a challenge, since there's less storage space for an extra tank. We also wonder about having a heated tank of oil next to a bag of groceries. Just keep the ice cream and other frozen foods in separate area, and they'll probably be OK.
A certain amount of mechanical understanding, if not experience working with diesels, is helpful. However, one customer we met, Paul Powers, who runs a Chevy C4500 Kodiak outfitted with a utility bed and camper top, admits to minimal experience working on diesels. He's thrilled with his Veg Powered Systems, and he runs it up and down the state of California. He reports no difficulty towing a trailer loaded with a steam cleaner which he uses to maintain supermarket parking lots all around the state. He also notes with pride that he recently saved more than $1,500 on diesel fuel on a trip from Southern California to Canada and back, in which he ran on vegetable fuel for 95 percent of the time. "It's a great feeling to get in a vehicle and go, knowing you're burning vegetable oil," he enthuses.