Butanol has been considered an attractive alternative fuel for automotive engine. In the present study, a numerical study is conducted in a spark-ignition engine fuelled with blends of gasoline and 1-butanol at different fuel/air equivalence ratios. The effect of fuel/air equivalence ratio on engine performance is analyzed. The results show that the peak pressure and peak temperature increases with the increasing of fuel/air equivalence ratio. With increased 1-butanol proportion, the incylinder pressure and incylinder temperature gradually decreases. In addition, effect of fuel/air equivalence ratio on nitrogen monoxide emission is depended on the proportion of 1-butanol in blended fuels.
For the electric vehicle motor controller driver section requirements of the multiple isolated power supply problems, analyzed the common DC/DC converter, the single-ended flyback converter was selected as the motor controller auxiliary power supply. Taking into account the parasitic parameters of the high frequency transformer and switch transistor effects on the circuit, the loss model was showed. Its feasibility is verified by experiments. Experimental results showed that the designed RCD clamp circuit switch could effectively reduce stress and meet the requirements of the motor controller.
The compressed air engine is receiving increasingly worldwide attention because it takes advantage of renewable energy and has zero exhaust emissions. This paper presents a systematic study on valve timing and size of a prototype compressed air engine for optimizing its efficiency and performance. An in-house air engine system model has been developed using the FLOWMASTER platform. The simulated results show that the optimizing valve timings is probably the most critical requirement in the compressed air engine design process.
A numerical study is conducted in a port fuel-injection, spark-ignition engine fuelled with 1-butanol at different fuel/air equivalence ratios and inlet air temperatures. The effect of fuel/air equivalence ratio and inlet air temperature on the engine performance and emission characteristics is analyzed. The modeling results show that the incylinder pressure and temperature increases with the increase of fuel/air equivalence ratio. The slightly lean mixtures offer the maximum level of NOX emissions. In addition, preheating the inlet air can increase the incylinder pressure peak value and NOX emissions.
With the growth of population, shortage of water resources, natural disasters, climate change, serious shortage of land resources and the development of urbanization and industrialization and impacts of other unfavorable factors, China's grain security issue has become a focus of public concern. Through the Chinese population quantity analysis and forecast of 2020 and 2030 the total demand of grain, comparison between total demand and current level of food production, China's grain problem is facing tremendous pressure. Water conservancy is the lifeline of agriculture and irrigation has great potential for grain production guarantee. Results for food safety in China made the following responses: First, the rational use of water resources, improve the efficiency of irrigation and grain yield per unit area. Second, multiple sectors such as agriculture, meteorology, soil, make a good combination of multiple disciplines for food security. Third, increase the peasants' production enthusiasm. Last, scientific and technological progress is the guarantee of grain production. In General, the issue of food security is national security, social stability, a top priority. The combination of our country's water resources crisis, limited rational development of agricultural water resources, improve the efficiency of irrigation, which will provide a guarantee for China agricultural water crisis, alleviating the shortage of water resources and increasing food safety assurance.
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