Executive Summary

      People in many parts of the world, including Africa and India, rely heavily on diesel engines for mechanical power.  This power is used to grind grain, pump water, and generate electricity.  Typically, the areas that rely on diesel-generated power are poorer, rural villages far from the electric grid and modern infrastructure.  The high cost of transportation combined with poor delivery systems have increased diesel fuel costs much higher than in more developed nations. 
      It is clear that the rural communities in these developing countries need a more reliable fuel source during this transitional period while they slowly build their economies and infrastructures.  Bio-fuels may be a viable solution for these rural communities.  While there are many high yield fuel oil crops that grow very well in depleted, un-irrigated land, the most popular internationally is the Jatropha Curcas oil.
      Our project looks into vegetable oil as a sustainable, rural energy solution.  We have developed a basic, inexpensive, modification kit for a diesel engine that allows it to run on raw vegetable oils.  This may allow remote villages to power their engines more reliably with locally grown products instead of fossil fuels.
The most common stationary diesel engines in rural Africa and India are single-cylinder, low-RPM designs similar to the British Lister engine.  They are older, purely mechanical designs popular for their reliability, longevity, and inexpensive price.  Common engine sizes are between 5 and 16 horsepower, which can provide a community of 300 to 1500 people all of its agricultural and potable water processing.
      Our modification kit is a universal design that provides two stages of controlled heating to bring the vegetable oils up to the desirable temperature range.  The components of the kit are easy to assemble and made of common materials and off-the-self parts.  Typical diesel engine prices are $250 in Africa and India.   Our modification kit without the benefit of mass production and economies of scale pricing is $274.  A year’s worth of diesel fuel for a 1000-person community is roughly 1500 gallons or $4500 .  Therefore, a village could produce all of their fuel on 1.8 hectares (4.5 acres) of land . 

System Design:
      There are several critical constraints for our design.   The most important design requirement is the fuel oil viscosity.    For the fuel injector to work properly the fuel oil viscosity must be lowered to a level similar to that of diesel, or about 5 centistokes.   To reach this viscosity, the vegetable oils need to be heated to a temperature greater than 200° F.  Waste heat from the engine is used to minimize the amount of electrical heating and to maximize the efficiency of the system.        
      Another key factor in our design was system cost. The system is designed for developing countries; therefore keeping the total cost low is a priority.   In addition, fuel used for testing proved to be a major constraint. Jatropha oil is not commonly grown in North America or Europe.   Therefore, obtaining the quantities of oil necessary for our testing proved impossible.   We were able to obtain sample amounts of jatropha from India, which we used to do viscosity testing.  Rapeseed (Canola) oil, which has a similar viscosity curve to jatropha, serves as our replacement.
      The last important feature of our design is its autonomous operation. Engine longevity can be drastically reduced because of improper oil heating. Additionally, too much heating causes system inefficiency as well as potentially dangerous premature combustion. A proper heating range is important to safety and engine operation. A straightforward reliable heating control system is a required design component

Design Strengths:
      Our final design incorporates all of our identified constraints in a small, robust package.   It uses basic, inexpensive components creating a universal modification kit for stationary diesel engines. It maximizes system efficiency by a utilizing a simple control of waste engine heat recovery and electrical heating elements. Lastly, the modification kit provides safe, autonomous, and sustainable mechanical power to the engine user.

Design Weaknesses:
      Currently, the only major weakness to our design is the reliance on AC power. Commercially available heat rope is designed for AC power. Often the engines are used to generate household/community electricity.  Therefore, AC generators or inverters coupled with alternators can supply the needed power.  Some engines only have an alternator to charge batteries in this case some form of a DC heating element would need to be designed. Additionally, for applications where the engine is used predominantly for milling and water pumping, electrical generation is a major additional cost to the system.