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Ethanol as a renewable fuel has been used widely in vehicles. Dual fuel injection is one of the new techniques in development for increasing the engine's thermal efficiency and reducing the pollutant emissions. This study reports experimental investigation to the dual ethanol fuel injection with a focus on the effect of spark timing on the engine performance at different volumetric ratios of ethanol directly injected to ethanol port injected. Experiments were conducted on a single cylinder 250cc spark ignition engine at two engine loads and 3500 RPM. The spark timing was varied from 15 to 42 CAD bTDC at the light load and from 15 to 32 CAD bTDC at the medium load, while the volumetric ratio of direct injection (DI%) was varied from 0% to 100%. Experimental results showed that DI100%, the best indicated mean effective pressure (IMEP) and thermal efficiency occurred at around 30 CAD bTDC at the light load and 23 CAD bTDC at the medium load, which were the minimum spark advance for the best torque (MBT). At MBT spark timing, the IMEP at DI56% and light engine load was 8.28% greater than that at 15 CAD bTDC which was the original spark timing set by the manufacturer, and the combustion duration (CA10-90%) was 41.8% shorter. These results were attributed to the improved combustion phase associated with the increased combustion pressure and temperature when the spark timing was advanced. However, the indicated specific hydrocarbon and carbon monoxide emissions increased with advanced spark timing and increased DI ratio. These could be caused by local rich mixture formed by fuel impinged to the chamber walls and the ethanol's cooling effect associated with the direct injection. On the other hand, because of the charge cooling effect of DI, the indicated specific nitric oxide emission decreased with increased DI ratio. At MBT timing and light load, the indicated specific nitric oxide emission decreased by 37.53% at DI56% and 67.39% at DI100% compared to port injection only.

From the time immemorial, the sun is the major source of energy for life on earth used for heat and lighting. Nowadays, solar energyhas been known as a renewable energy source. It is an alternative energy to that of fossil fuel and it can be collected from the renewable resources such as sun, wind and hydro. This paper introduces a new development of grass cutter, named as Smart Solar Grass Cutter, by usingsolar irradiance as a primary energy source with the presence of a solar panel. This grass cutter prototype is developed to reduce air pollutant and improve the current design specifically the blade position based on the previous studies. With current technology, this new prototype is designed as remotely controlled grass cutter using Arduino UNO. Smartphone is used as the remote controller. After developing an established prototype, the design analysis is carried out to bevalidate with the theoretical values to ensure that the prototype can be safely used. The Smart Solar Grass Cutter can operate more than two hours when the used battery is fully charged. Based upon the results, the Smart Solar Grass Cutteris reliable with high efficiency of the system compared to the previous studies. Therefore, it can be concluded that the prototype is reliable and environmentally friendly

Dual injection of ethanol fuel (DualEI) has been in development. DualEI has the potential in increasing the compression ratio and thermal efficiency of spark ignition engines by taking the advantages of ethanol fuel properties and the direct injection. This paper reports an experimental investigation of the effect of direct injection (DI) timing associated with spark timing on the performance of a small DualEI engine. Experiments were conducted with fixed port injection timing and varied DI timing before (early) and after (late) the intake valve closed at 3500 RPM and two load conditions. Results show that the engine performance is enhanced by early DI timing, although the variation of IMEP and indicated thermal efficiency with DI timing is not significant either with early DI timing or in most of the tested conditions with late DI timing. Only in the medium load condition when the DI timing is retarded from 80 to 60 CAD bTDC, the IMEP and thermal efficiency significantly reduced by about 16% due to the increased initial combustion duration, resulting in reduced flame speed and increased combustion instability. The results also show different effects of early and late DI timing associated with the spark timing on engine emissions. With late DI timing, the engine emissions of CO and NO increase with the advance of late DI timing and spark timing. With early DI timing, the engine emissions increase with the advance of spark timing. However, the variation of engine emissions with early DI timing is more complicated than that late.

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