One of the many things that I like about diesel engines is that they can be run on a number of different fuels. I know that gasoline engines can too (namely alcohol) but diesels can be run on a pretty wide variety of fuels with little or no modifications. In fact when Rudolf Diesel designed and tested his engine design he designed it to run first on coal dust, then on peanut oil, and it wasn’t until later on in the development process that he considered petroleum distillates as potential fuel sources for his design. That being said, some modern designs of diesel engines are better suited for operation on alternative fuels than others, but pretty much all diesel engines can be run on fuel types other than pump diesel with varying degrees of success.
First of all, lets talk about the commercially available kits for WMO/WVO use. These systems are generally two tank systems (a separate tank for the WMO or WVO) that introduce a very important ingredient to the equation — HEAT. Waste vegetable oil has probably gotten the most attention for use in automotive applications and at temperatures below 50 degrees or so many types of wast veggie oil congeal and turn to a semi solid mass of gelatinous goo. To use this stuff as fuel, you have to keep it liquid, and to achieve a good atomization you have to have it pretty hot (typically around 140-170 degrees Fahrenheit). This works great for every day use, but in the event of an emergency, unless you have all the parts on hand to assemble your own conversion kit, you need to use what you have. That is what I want to discuss. Also, for the purposes of this discussion, I do not plan to cover the use of Biodiesel, as I don’t feel it is an especially practical fuel for emergency use due to the need for processing equipment, a substantial supply of waste vegetable oil, and special chemicals necessary for the process.
Aside from commercially available kits to convert your diesel engine for running alternative fuels like waste vegetable oil (WVO), Waste Motor Oil (WMO), Waste Automatic Transmission Fluid (WATF) for everyday use, and the Biodiesel mentioned above let’s take a moment and consider the options available as alternative fuels in the case of an emergency situation as well as some of the downfalls of each.
Waste Motor Oil (WMO) – This is the black gold that you typically drain from the crankcase of your car every 3,000 miles or so (you do change your own oil right?). Methods for using WMO vary from running it in a heated tank like you would WVO, to running it straight in warmer months. One method that is gaining popularity in some circles is the process known as blending. This involves adding a set percentage of a solvent of some sort (typically pump diesel, unleaded gasoline, or even paint thinners can be used) and then allowing the mixture to settle in a tank to let the impurities settle to the bottom of the tank. This type of fuel is known by the generic name W85 in many instances because it is 85% (approximately) waste oil. The “cleaned” fuel is then pumped, siphoned, or drained off the top of the tank and used in the vehicle. I have done a fair amount of “tinkering” with different mixtures and concentrations as well as different solvents and I have burned a decent amount of this type of fuel in my truck with varying degrees of success. Chronicling these experiments is probably reserved for another blog post, but be aware that waste motor and hydraulic oil, as well as automatic transmission fluid can be used as fuel with some filtering and the use of a solvent.
Waste Vegetable Oil (WVO) – WVO can obviously be used as a motor fuel, but as stated above in cooler weather the fuel gels at a relatively warm temperature. In warmer months, however WVO can be used as a motor fuel in warmer months as long as you keep a couple things in mind. First of all, it must be cleaned sufficiently. Most WVO has lots of grit in it; think french fry fragments, chicken breading, and worst of all water. Removing these contaminants takes some filtering and work, but it is doable. Second, starting the engine on another fuel is best. If you can start the engine of pump diesel and warm it up on that before switching to WVO it will considerably reduce coking (which is a process of the ash created by burning the fuel building up inside your engine. One major downfall of using WVO is that WVO and mineral oil (WMO or the oil in your engine) create a black sticky, polymerized goo when they are combined. Even mixing some of them together in a container and allowing it to sit for a while will reveal the results of this process. Having this happen inside your engine is a disaster that can ruin the engine. So much for running on alternative fuels, huh? Be careful with WVO. Its best use in my opinion is for being processed into biodiesel, which as I have said is not the best alternative fuel for emergency use because of the relatively complex process required to produce it.
Home heating oil (HHO) – Fuel oil is very Very close in its composition to diesel fuel and they can be used almost interchangeably. Kerosene is similar in composition as well, although it has been further refined to remove additional impurities to improve the cleanliness of the burn. Both HHO and Kerosene can be used as a motor fuel. Diesel fuel, can by the same token be used for home heating purposes, but it does not burn as clean and produces a bit more smoke, so care should be taken when using it as a home heating fuel. I would not recommend either one for use in a ventless design Kerosene heater as the diesel fuel almost certainly produces more carbon monoxide than relatively clean burning kerosene would. This is one reason why diesel engines are a preference for me as we typically have at least a hundred gallons of fuel oil on hand for home heating purposes. Having this safety net in case of a medium term emergency is a nice reassurance against running out of fuel for the generator and or truck especially since we can heat our home entirely off wood should we so desire.
As I stated above there are a number of different ways to approach the use of alternative fuel in the case of an emergency, but almost all the alt fuels will require some sort of filtering. Commercially available filter vessels and filters are, of course, available for this purpose, but regular residential water filter housings can be used in conjunction with filter media of varying compositions to filter the oil down to a size of about 5 microns. This is a process that I have been using under gravity pressure with pretty good success. Allowing the oil to pass through the filter at no more than gravity pressure prevents the oil from passing through the filter too rapidly to filter properly. It isn’t a quick process, but I am in no hurry anyway (at least when it comes to this process).
At some point in the future I may go into more detail about the specifics of these processes but for now, a brief overview of the alternatives is what I was hoping to achieve.
Just another reason why the diesel is a viable and some may argue, superior motor fuel.
‘Til we meet again,