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Plant oil engines & plant-based fuels

Written on: Sunday October 28th, 2007

One of the reasons that Michelle and I found the Folkecenter was because of plant oil. Just over a year ago, Michelle and I converted our VW Westfalia van to run on used vegetable oil, usually from deep fryers. Before I did this I had a lot of help from my good buddy and fellow greaser, Adam Gagnon. Adam has been on the plant oil beat for a number of years now and knows the system inside and out. He runs a small company in Calgary called Crude Country Biofuels and specializes in converting diesel engines to run on plant oil. As Adam and I got to know each other Adam started letting me in on all of the plant oil secrets, one of them being the Folkecenter. The Folkecenter has been pioneering plant oil in Denmark for many years now and has produced a number of very highly regarded papers on decentralized cold pressing of plant oil, and on the energy balance of using plant oil as a transport fuel. Adam showed me these papers and I immediately became enthralled by the Folkecenter. After a few phone calls to the center I had the van converted and a plane ticket for Michelle and I to work and study here.

Vegetable oil as fuel is commonly referred to as PPO or Pure Pant Oil. Numerous types of plant oils exist including rape seed, canola, safflower, sunflower, jatropha, jajoba and the list goes on and on.

In order to understand how PPO can operate in a diesel engine we must look at the operation of the diesel engine. The diesel engine differs from a gas engine in that it does not combust fuel using a spark. The combustion process in a diesel engine uses a process call compression ignition or CI. Essentially, air is compressed in the cylinder by the piston to as little as 1/15th of its original volume. This raises the temperature of the air to the autoignition temperature of diesel. Diesel is then injected using a high pressure injection pump and injector into the piston at which point the mixture explodes and creates force to turn the engine crank and your wheels.

If we look closer at both canola and diesel we start to see that there are a number of similarities between the two which is why we can burn it in a diesel engine. However, one of the main differences that has to be overcome is the difference in autoignition temperature of diesel and canola. The auto ignition temperature of diesel and canola are 210 and 345 degrees centigrade respectively. Therefore, in order to use a vegetable oil like canola in a conventional diesel one first has to compensate for the higher autoignition temperature.

This is where Crude Country Biofuels comes in. Adam Gagnon has been perfecting conversion kits for diesel engines for a few years now and I must say he has a pretty rock-solid set up. Adam?s system relies on two separate fuel tanks, one diesel and one plant oil. The diesel is used to start the engine and warm it up preparing it for vegetable oil. Once the engine is warm he flips a switch and starts burning plant oil. In order to operate on a fuel with a higher autoignition temperature Adam specs out a heating element which is sized based on the fuel flow rate of the engine; the bigger the engine the bigger the heater. Too big and the oil will burn, too small and the oil will not get hot enough. If all the components are sized correctly the system should run like a top and provide many ?free? kilometres or driving. He also has a series of additional components that he can add to the plant oil fuel system to make it winter compatible. I have personally seen Adam start his little VW Greasy Rabit in -20degC weather with no issues. Adam has driven this car over 75,000km on plant oil which included a trip to Mexico and back. Michelle and I plan on taking our Westy on a similar trip next year and driving on as much PPO as possible.

 

Here in Europe a different approach is taken as operating vehicles on plant oil is much more common. Elsbett Engine AG , produces an engine that can operate on vegetable oil directly. They also produce a kit that allows users of vegetable oil to start up directly on vegetable oil eliminating the two-tank system. The Toyota truck here at the Folkecenter that we reported on in one of our earlier blogs uses an Elsbett conversion kit and it works quite well.

The single tank system operates on the same principal as the two-tank system, with a few minor changes. The main difference being that there are additional heating devices that are used in order to preheat the fuel prior to start up.

Now that I have had the opportunity to operate both a one-tank and two-tank system I can say that I much prefer the latter system.

The main advantages of the two-tank system include:

1) The ability to flush the engine of vegetable oil before you shut off your engine

2) Better cold starting capabilities in the winter, a must in Canada

3) Cleaner starting, when starting on vegetable oil it is hard to get the right autoignition temperature right off the bat as the engine is cold and there is fuel in the injection lines that is hard to heat. The Toyota here also runs quite rough right off the bat when starting on PPO.

The disadvantages of the two tank system include:

1) Potential loss of luggage capacity if the tank inside the car

2) Additional weight in the car, reducing fuel economy

3) More plumbing and complexity to the fuel system which can cause problems if not installed properly.

So as with most things in life there are always compromises that must be made when choosing which way to go. If you are interested in exploring plant oil as a more renewable fuel in the future feel free to check out Adam?s website and send him a line. He is good guy and always open to chatting over a good pint of beer at the Wildwood in Calgary.


Benefits of Biofuels

Biofuels can offer many benefits over conventional fuels if used properly. It has been proven that canola oil burns far cleaner than diesel with fewer particulate and less CO2 than diesel. The canola oil also lubricates the fuel system far better than diesel and some people argue that the engine runs quieter on vegetable oil. I am not going to go into the energy balance in this blog as it is starting to get very long but I will place a link here so that people interested can look for them selves.

Ethics of Biofuels

After you read this article you may want to go out and convert your very own engine to run on PPO. But before you do you should consider the ethics of biofuels. This is becoming an ever important issue in the world as biofuels used incorrectly can be far worse than using petroleum diesel. Firstly, when farmers start growing fuel instead of food there can be severe ramifications to the food system throughout the world. The corn riots in Mexico two years ago is a direct result of the US corn-to-ethanol policy. Also, consider that one SUV tank of corn ethanol consumes roughly enough corn to feed one person for a year.

Truthfully the Ethics of Biofuels requires a full blog and I will put one together in the coming months. Michelle, Melissa and I are preparing a biofuels conference at the end January here at the Folkcenter in which key people in Europe are going to gather to discuss if biofuels can be implemented sustainably. As this issue develops we will keep you abreast of the events and prepare a blog on the ethics of biofuels.