Abstract.To help reduce dependence on fossil fuels for mechanized farm operations, we developed and tested a distiller using fermented nipa sap with 7% alcohol content and diluted nipa sap fermentation liquor or crude bioethanol (15% concentration) to produce fuel-grade bioethanol for small spark-ignition engines. Keywords: Click here to enter keywords and key phrases, separated by commas, with a period at the end

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A variable-feed hydrous-bioethanol fuel injector (VFHBFI) for retrofitted engine was designed and evaluated to provide a technology that would allow spark-ignition engines commonly used by farmers be fuelled with hydrous bioethanol from nipa. With this technology, farmers can make use of their farm resources to fuel their engines making them less dependent on imported fossil fuel. The VFHBFI consists of the following components: 1) Fuel tank; 2) DC pump; 3) Fuel line; 4) PWM switch; 5) Battery; and 6) Fuel injector. The tank is made of a stainless-steel cylinder with 2-liter capacity of hydrous bioethanol (95%). The DC pump that feeds alcohol fuel is a diaphragm-type operating on a 12-volt line. It is ran by a 16-AH gel-type battery and its pumpingrate is regulated by a 12-volt, 0.8-Amp PWM switch. The position of the switch and of the battery is dictated by the kind of machine to be powered. The fuel line that delivers the alcohol to the engine is made of an alcohol-resistant plastic hose. The VFHBFI was evaluated using a 6.5-hp spark-ignition Kenbo engine retrofitted to utilize hydrous bioethanol as fuel. The fuel feed rate was calibrated with the PWM switch setting. A micro-tiller and a power-tiller-operated hauler were used in the evaluation. The forward speed of the power-tiller-operated hauler was also evaluated at varying load. Results showed that the VFHBFI performs satisfactorily as per design. The fuel feeding rate of the injector behaves linearly with the PWM switch setting. It was observed that smooth engine speed is achieved at medium to high PWM switch setting. Using the VFHBFI, a retrofitted-engine-driven micro-tiller successfully tilled a 1500 m 2 farm making it ready for planting in 2 to 3 passes. The average amount of fuel consumed in tilling was 2.0 liters per hour, which is double than when using pure gasoline as fuel. Also using the VFHBFI, a retrofitted-engine-driven power-tiller hauler consumed an aver