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The performance of biodiesel in a single-cylinder diesel engine was studied and optimized by varying the engine settings, including the injection timing, injection pressure, and fuel pump plunger diameter. The engine emissions were found to be lowered for particulate matters (PM) and hydrocarbon (HC) with the use of biodiesel, but an obvious increase in the oxides of nitrogen (NOx) was observed, particularly at high engine loadings. The results revealed that individual adjustment of the above-mentioned parameters could not acquire a good balance between PM and NOx emissions. On the other hand, multiparameter engine adjustment with the consideration of their cross-interactive effects can keep the benefit of reducing PM and HC without increasing NOx emission and sacrificing fuel combustion efficiency.

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The present paper investigates the performance of a special micro-wind turbine designed to capture wind energy in rural as well as urban environments. Different from traditional kilo-to megawatt size wind turbines which can be connected directly to the grid, the microwind turbine system is flexible in size and linked with small generators that generate electric power at the site of installation for easy applications. The main advantage of this micro-wind turbine, apart from its low cost, is that it can be propelled by a wind speed as low as 2 m/s. To extract more wind energy, several such micro-wind turbines can be connected together by their external gears into an array to increase their swept areas and hence power. In the study, the performance of a single micro-wind turbine was simulated using computational fluid dynamics (CFD) and validated through physical experiments. The experimental results on angular velocity and power developed showed a good agreement with those predicted by the CFD simulation. The validated computer model was then used for a parametric study of the wind turbine with varying blade subtend angles and number of blades, both of which affect the torque acting on the wind turbine and the power performance. The design of the wind turbine blade was optimized through the CFD simulation. This paper considers mainly the aerodynamic performance of a single turbine and issues relating to its practical deployment are not dealt with.