One of my Biodiesel Jetta TDI's

This title is a little misleading if you have read my post on “Using Biodiesel in your Vehicle.”  In reality, I’m going to provide information on how you can prepare your VW TDI to run on biodiesel.

In general, there are two issues to overcome when running a vehicle on biodiesel:

1. Biodiesel degrades some soft fuel lines that are not rated for alcohol-type fuels like ethanol, methanol and biodiesel.  Any soft lines that are not compatible should be replaced to prevent premature degradation and fuel leaks.
2. Older diesel vehicles develop sludge and residue in the fuel tank from diesel fuel.  Biodiesel is a solvent and will dissolve the sludge sending it through the fuel system over a short period of time.  This will clog fuel filters rapidly until all of the sludge is dissolved and passes through the fuel system.

I have two ’99 VW Jetta Mk IV TDI cars.  Both of them have the VW 1.9 liter ALH A4 turbodiesel engine.  This engine was delivered in the Volkswagen Jetta and Golf from the second half of 1999 to the end of 2003.  It was also delivered in the New Beetle from 1998 to 2003.  This article describes how to resolve the two issues above specific to the MkIV ALH A4 diesel engine.

Replacing the non-compatible fuel lines.

On the Mk IV engine, the only fuel hoses that are not compatible with biodiesel are the fuel return lines that are located between the injectors and the return line on the injection pump.  They must be replaced with viton, fluoro-elastomer or fluoro-elastomer-lined hose.  The easiest way to do this is to buy a viton return hose kit for the VW TDI MkIV from Grease works in Corvallis, Oregon.  The full kit costs less than $20 and is easy to install.  The second option is to buy bulk hose in the correct size from an industrial supply company and make the kit yourself.  In addition to cutting the hose to fit, you will need to have a crimping tool and the correct size hose plug for the terminator on the last injector.  The correct hose size is 3mm ID in “soft” consistency.  The firm or hard consistency doesn’t allow for easy bending between injectors.

Cleaning out the fuel tank

Years of diesel fuel in a tank will cause sludge to form on the inside of the tank.  Biodiesel is alcohol-based and serves as a solvent when introduced into the fuel tank.  The sludge is dissolved into the fuel and enters the fuel lines and fuel filter.  For an older vehicle, this may clog the fuel filter very quickly.  Here are my recommendations on slowly cleaning the fuel tank.

1. Do not use 100% biodiesel until your tank is clean.  (B100)  By using B20, you will slowly dissolve the diesel sludge without quickly clogging the filter.
2. Use B20 for the first five tanks of fuel and then change your fuel filter.  After this, you should be able to run B100 but keep a spare fuel filter with you.
3. When your car starts to lack power, it’s time to change the fuel filter again.  After this second change, you should be able to go back to regular fuel filter changes.

Biodiesel in blends greater than 50% work very well in the summer in Georgia.  Once the temperatures drop below 40 degrees, I recommend switching to B30 or less.  Biodiesel will begin to gel at temperatures under 40 degrees.  Gelled biodiesel will quickly clog your fuel filter and cause a very large mess.  By following the recommendations above, you should find running biodiesel a pleasant experience.  It sure smells a lot better than diesel and will make you feel better about your carbon footprint.

My 1970 Mercedes 220D Veggie Car

As part of my “no nonsense” series on bio and alternative fuels, I covered biodiesel and straight vegetable oil (SVO) and waste vegetable oil (WVO) diesel conversions.  Since I believe in experimenting first-hand with topics I discuss, a few years ago, I worked with a local company to convert a restored 1970 Mercedes 220D to run on vegetable oil.  I have had one other veggie car before “Helga” the Mercedes and you can read about the “Veggie Ranger” conversion on Greasology.com.

Restored Vintage Mercedes 220D Diesel

Why did I pick an old Mercedes?

Even though the first diesel engines built by Rudolf Diesel in the late 1800′s ran on plant oils, modern diesel engines are far removed from those first engines.  They use direct injection with high pressure common rail fuel systems with computerized injection and timing.  They use sensors everywhere that expect a fuel that has the same viscosity and cetane rating as diesel fuel.  They are also not very tolerant to water in the fuel

Helga the Veggie Mercedes interior

The 2.2 liter, indirect-injected, mechanical diesel in the Mercedes 220D is much closer to the first diesel engines and is a much more forgiving and tolerant engine for burning alternative fuels.  There are no computers or sensors.  Combustion occurs in a “pre-combustion” chamber off the side of the main cylinder (there are four of them).  This helps prevent carbonization of the piston rings in the cylinders since unspent fuel is carbonized in the pre-combustion chamber instead of in the cylinder.  This is very important for diesel engines that are run on vegetable oil.  It is common for veggie fuel to enter the combustion chamber at lower than optimal temperature which causes the fuel to be sprayed in a less than optimal pattern.  This causes some of the fuel to carbonize on the walls of the combustion chamber.  In modern diesel engines, fuel is injected directly into the cylinder.  Therefore, the carbonization occurs on the head of the piston and eventually on the walls of the cylinders.  This causes carbonization on the piston rings which eventually fouls them causing breakage and a dead engine.

Helga's Converted Engine Bay

There are some sophisticated and well-designed vegetable oil conversions such as the Frybrid and Vegistroke conversions that are designed to perform on modern, direct injection diesel engines but still require a very careful fuel preparation system.  This is a highly debated topic in the Grease Community but my recommendation would be to go with an older indirect injection diesel engine if you want to experiment with veggie fuel.

Helga's Veggie Fuel Tank

How Does the Conversion Work?

Helga has a coolant-heated, two tank system with a looped return.  There are two parallel fuel systems that connect before the injection pump on the supply side and after the injection pump on the return side.  It was designed by Rob del Bueno of Vegenergy Fuel Systems and installed by Dezso Gavaller.  Rob is an experienced resource in the biofuel industry and is the star of the VegMyRide Instructional DVD on converting a diesel vehicle to vegetable oil.  You can order the video direct from Rob if you want a copy (link coming soon).  It includes all of the conversion fuel diagrams including the system installed in Helga.  Here is a brief description of the system:

1. A custom-welded tank with an integrated heat exchanger.  Coolant from the engine is looped through the heat exchanger welded into the tank to heat the vegetable oil.
2. Hose on hose (HOH) fuel lines from the fuel tank to the heated fuel filter. The coolant lines that take engine coolant to and from the engine are wrapped together with the vegetable oil fuel line as it runs from the tank to the fuel filter.  This keeps the fuel heated from the tank to the fuel filter
3. Coolant-heated fuel filter on the vegetable oil side of the fuel system. The head of the filter is a coolant-based heat exchanger that also uses waste heat from the engine to heat the oil coming from the fuel tank.
4. Arctic fox inline coolant-based heat exchanger. This is the last point of heating the fuel before it flows through the valve and into the injection pump.  Coolant that leaves the engine is at its hottest point so it flows first through the arctic fox, then through the fuel filter and then onto the fuel tank through the HOH lines to the tank.
5. Switching valves. One switches the fuel source from diesel to vegetable oil.  The second valve switches between returning diesel to the diesel tank and looping the return back into the fuel supply line.  The loop is used when the system is running on vegetable oil and during the diesel purge process.

How do I Operate the System?

When you first start the engine, the fuel system should be set to diesel and return. (there are two switches)  the engine is cranked and warmed up on diesel fuel.  Once the engine reaches operating temperature, both switches are flipped to the right simultaneously switching the fuel system to veggie and the return to a looped return.  You can now drive on veggie until you’re approaching your destination or you start to run out of vegetable oil.  When you are a few minutes from your destination, you need to begin the diesel purge process.  Flip the fuel selection switch back to diesel but leave the return switch on looped return.  Diesel enters the fuel system and return loop diluting the vegetable oil until it is almost completely diesel fuel.  This is usually about 1-2 minutes in Helga when driving on the highway at 65mph.  Once the system is purged, the return switch is flipped back to diesel return.

Helga's Veggie System Control - diesel/veg on left, return on the right

Pro’s and Con’s?

My overall experience with this car was positive.  However, I was very meticulous in doing research on the right vehicle, picking a well-designed conversion and performing proper filtration and dewatering of the fuel.

Pro’s

• Once I had the operating procedure down, the system was easy to operate.
• I used approximately 90% vegetable oil fuel on my 80 mile daily commute to and from work.
• I didn’t have any vegetable-oil related problems with the vehicle or fuel system during the year and a half that I used Helga as a daily commuter
• I only replaced the veggie filter one time during the time I owned her.
• The exhaust smells like french fries.
• There is no particulate in the exhaust so it doesn’t bother folks with breathing issues like asthma.

Con’s

• The conversion cost around $1700 installed.
• Fuel acquisition from restaurants is competitive, time consuming and messy
• Fuel preparation is messy and time consuming
• Most diesel mechanics won’t work on your veggie car or truck

Overall, I enjoyed running my two veggie vehicles and didn’t have any issues with the conversions or driveability.  However, they were well-designed and I took the proper precautions and procedures when preparing the vegetable oil for use.  I also perform most of my own vehicle maintenance and would consider myself an advanced “shade tree” mechanic.  I would not recommend veggie cars to someone that is not mechanically-inclined unless you find an installer that will provide all of your vehicle maintenance for you.

For more information on using vegetable oil as a diesel fuel, see the following “NotPetroleum-approved” internet sources:

Greasology.org

InfoPop SVO forum

Frybrid Forum

Vegistroke site

Biodiesel is a Clean Alternative to Petroleum

Any diesel engine can run on biodiesel.  Is that a true statement?  Are there any issues to deal with or do you just dump the “biodiesel” into the engine?  What is biodiesel anyway?

There are lots of questions that should be answered when you begin to peel back the onion on running your vehicle on biodiesel.  This article will attempt to demystify biodiesel and answer some of those questions.  This is part of our “no nonsense” series on biofuels as a partial solution to wean us off of petroleum.

What is Biodiesel?

Biodiesel is a fuel made from renewable plant oils and animal fats.  It differs from plant oils and animal fats in that it must first be reacted with an alcohol and catalyst before it becomes fuel.  After the reaction, the biodiesel must be separated from the non-reacted oil/fats, leftover catalyst and glycerine by-product.  The resulting fuel must also be washed and dried to remove any impurities before the fuel is ready to run in a diesel engine.

If you use biodiesel in its purest form in an engine, this is known as B100 or 100% biodiesel.  When the pure biodiesel is blended with regular diesel in different proportions, it is still considered to be “biodiesel.”  It has different designations depending on the percentage of biodiesel that is mixed with the regular diesel fuel.  The most common commercial blend of biodiesel consists of 20 percent pure biodiesel and 80 percent regular diesel.  This is known as “B20.”  Some vehicles are only warranted to run on B5 or 5% pure biodiesel.  This is such a low percentage of biodiesel, most consider this to be regular diesel fuel with an additive.  It is similar to gasoline that uses a 5% ethanol additive.  (oil companies used the toxin MTBE until they realized how bad it is and switched to ethanol)

The American Society for Testing and Materials created a standard testing procedure for biodiesel known as ASTM D6751.  Biodiesel for commercial sale must be tested to make sure it meets this standard before it is approved for sale as a fuel.  For more information on the process of making biodiesel, see these NotPetroleum-approved links for information and technical discussion:

Collaborative Biodiesel Tutorial

InfoPop Biodiesel Discussion Forum

What is NOT Biodiesel?

Biodiesel is NOT waste vegetable oil, plant oil or animal fats.  Those are all feedstocks that are used for making biodiesel.

Biodiesel is NOT vegetable oil mixed with diesel.  Some people use this as a fuel in diesel engines but it is not biodiesel.  This can work as a fuel since it cuts down the viscosity or “thickness” of the vegetable oil so that it will run in a diesel engine.  This is not recommended as a fuel for modern diesel engines.  It can work in some engines but requires an in-depth knowledge of the internal components of different types of diesel engines and some understanding of thermodynamics.  If you are not a tinkerer and are not technical, don’t try this.

One of my Biodiesel Jetta TDI's

Does Biodiesel “just work” with a diesel engine?

Yes and No.  You can dump biodiesel in a diesel engine and it will burn as fuel.  However, since biodiesel is an alcohol, it will eventually degrade seals and hoses that are not rated for alcohol.  The most common material for making alcohol-resistant seals and hoses is called a “fluoro-elastomer.”  The most common version of this is called Viton and is made by Dupont.

If you are running B20 biodiesel in a modern diesel vehicle, the dilution factor will help prevent this degradation.  Also, most modern diesel engines use viton seals and hoses with viton lining.  If you would like to use pure biodiesel (B100) in a vehicle, make sure your seals and hoses are viton or have been replaced with fluoro-elastomer materials.  Most auto parts stores carry “high pressure fuel hose” which normally has a fluoro-elastomer lining and comes in several sizes.  To be certain, make sure the host is marked with the following designation: “SAE30R9.”  Hose with this marking has the viton lining.

Most vehicles are warranted for only B5 and some for B20.  If you run less diluted versions of biodiesel you will void the warranty.  Make sure you take this into consideration before running more than the recommended blend of biodiesel in your vehicle that is still under factory warranty.  One last word to the wise: remember that viton is “alcohol resistant” and not “alcohol proof.”  If you run B100 on a regular basis, you will eventually have to replace the viton seals and hoses.  However, the life is probably closer to the regular replacement cycle on hoses that are used with regular diesel fuel.

Do I need to “convert” my car to run on biodiesel?

The only conversion necessary is to make sure that your hoses and seals are made from an alcohol-resistant material like Viton.  (see information in the section above)

"Clifford" my biodiesel Dodge Cummins 12 valve

How do I make Biodiesel?

Biodiesel does not require a special facility or laboratory to produce the reaction.  However, it can be dangerous and could cause bodily injury or death.  I would NOT recommend doing this in your garage or at home.  There are good instructions on the internet on how to make biodiesel yourself and some commercial devices to make the process less cumbersome if you have a safe place to make it and have knowledge of Chemistry.  Proceed at your own risk!

Where do I buy Biodiesel?

The best way to find commercial biodiesel retailers in the United States is to use the biodiesel finder site at the National Biodiesel Board.  If you are located in other regions, I would recommend googling “biodiesel” and your location to do some research on where to buy commercial biodiesel.  Make sure you are buying from a licensed facility.  If not, make sure the fuel is tested and certified ASTM D6751 to prevent damage to your vehicle from dirty, un-reacted fuel or worse.

Can I run my car on vegetable oil?

You can run a diesel vehicle on vegetable oil.  However, it is much more difficult than using biodiesel.  I used to teach a class to elementary and middle school children on running cars on vegetable oil.  The easiest way to explain it to them was to tell them there are three basic steps to making waste vegetable oil work as a diesel fuel: “Get it CLEAN, Get it DRY and Get it HOT”

One of my Experimental Veggie Vehicles

There is much debate around what is required to make a diesel engine run on vegetable oil and which types of engines will work.  Here are some NotPetroleum-approved links to find out more information on how to make this work.

Greasology WVO Tutorial

InfoPop SVO Discussion Board

What do I have to do to make waste vegetable oil work as a fuel?

Get is CLEAN, Get it DRY and Get it HOT.  Choose an older diesel Mercedes built before 1986 if you want to experiment. However, make sure you like to tinker with car maintenance yourself since these cars are old and require a lot of regular maintenance.  After all, they are at least 25 years old and are often neglected.

VeggieRanger Teaching a Class on Veggie Fuel

Do NOT buy a new $50k diesel truck and hand it over to a hippie to convert it to vegetable oil.  There are sophisticated vegetable oil conversion kits that will work with new trucks if they are installed by a professional.  If you want to go this route, google “Frybrid” and “Vegistroke.”  These systems do work but only if you are experienced at preparing the oil as a fuel.

I hope this has given you enough information to better understand biodiesel and how you can use it as an alternative to petroleum.  Biodiesel isn’t the only solution for getting us off of our addiction to petroleum but it certainly can be a part of the solution and/or serve as a bridge to future technologies that are NotPetroleum!