Experimental Investigations on a Jatropha Oil Methanol Dual Fuel Engine

Use of vegetable oils in diesel engines results in increased smoke and reduced brake thermal efficiency. Dual fuel engines can use a wide range of fuels and yet operate with low smoke emissions and high thermal efficiency. In this work, a single cylinder diesel engine was converted to use vegetable oil (Jatropha oil) as the pilot fuel and methanol as the inducted primary fuel. Tests were conducted at 1500 rev/min and full load. Different quantities of methanol and Jatropha oil were used. Results of experiments with diesel as the pilot fuel and methanol as the primary fuel were used for comparison.

Brake thermal efficiency increased in the dual fuel mode when both Jatropha oil and diesel were used as pilot fuels. The maximum brake thermal efficiency was 30.6% with Jatropha oil and 32.8% with diesel. Smoke was drastically reduced from 4.4 BSU with pure Jatropha oil operation to 1.6 BSU in the dual fuel mode. Hydrocarbon and carbon monoxide emissions were higher in the dual fuel mode with both fuels. Heat release pattern in the case of neat Jatropha oil operation showed a smaller premixed combustion phase and a larger diffusion combustion phase as compared to diesel operation. These phases were not distinguishable in the dual fuel mode.