چكيده به لاتين
The emission of greenhouse gases and pollutants by vehicles is one of the most important challenges in the discussion of global warming and human health. In addition, the efficient use of energy from fossil fuels in vehicles is another global concern these days. Therefore, the use of low temperature combustion engines such as RCCI engines to solve these problems can be helpful. RCCI engines are controlled by injecting two fuels (a low-reactivity fuel that is sprayed into the port and another high-reactivity fuel that is injected directly into the chamber) into the chamber. So far, the use of various fuels (low reactivity fuels and high reactivity fuels) in these engines has been studied according to the amount of pollution and efficiency and the effect of spray variables on them has been investigated. In this study, considering the advantages of natural gas fuel and biodiesel fuel as a fuel pair in the RCCI engine, it has been tried to investigate the effect of variables on engine performance in this case by numerical simulation using Converge software; because for some of these changes, experimental testing is not possible. First, the simulation results were validated to provide the reliability of other results for discussion and comparison, then engine performance at different initial temperatures and then at different ratios of the two fuels were examined. The results showed that increasing the initial temperature of the mixture improved the quality of combustion and warmed the combustion, and as a result, the amount of carbon monoxide and unburned hydrocarbon pollutants were significantly reduced. Start of combustion when the initial temperature was 405 K was measured 5.7CAD earlier than when the initial mixing temperature was 355 K. Also, with increasing the percentage of fuel with high reactivity, a dual approach was observed in the amount of pollutants and combustion characteristics of the engine, so that with increasing the percentage of biodiesel fuel to 40%, higher and more complete combustion took place and with increasing, high reactivity fuel to 60% of the combustion was cooler and more incomplete.