Topic
NOx
About: NOx is a research topic. Over the lifetime, 26367 publications have been published within this topic receiving 496555 citations.
Papers published on a yearly basis
Papers
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TL;DR: In this article, a single cylinder diesel engine is employed as the test engine in the present work, and exhaust emissions such as CO, CO2, NOx, HC, and smoke are measured and compared with diesel oil.
156 citations
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156 citations
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TL;DR: In this article, the seasonal behavior of peroxide concentration is due to a transition between two qualitatively different photochemical states of the atmosphere, called the low and high NOx regimes according to whether radical production is greater or less than the NOx emission rate.
Abstract: Concentrations of H2O2, organic peroxides, and other photochemically generated species were calculated using a zero-dimensional box model. The range of emission rates considered centered on values that are representative of conditions in a moderately polluted region such as the eastern United States. Solar intensity, temperature, humidity, and mixing layer height were varied to simulate changing conditions over a yearly cycle. Predicted concentrations of H2O2 have a pronounced seasonal dependence similar to that observed. Evidence is presented that the seasonal behavior of peroxide concentration is due to a transition between two qualitatively different photochemical states of the atmosphere. These states are called the low and high NOx regimes according to whether radical production is greater or less than the NOx emission rate. In the low NOx regime, more radicals are formed than can be accommodated by reaction with NOx, and the “excess” radicals are removed by bimolecular radical-radical reactions leading in large part to peroxides. In this regime, peroxide formation is nearly proportional to the difference between radical source strength and the NOx emission rate and peroxide concentration scales with the factors affecting radical source strength (e.g., water vapor and photolysis rate constants). Radical production in the high NOx regime is insufficient to react with and remove all NOx. Consequences include the suppression of peroxide formation, a reduction in the oxidizing capacity of the atmosphere, and high concentrations of primary pollutants.
156 citations
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TL;DR: In this paper, the performance parameters and exhaust emissions of a diesel engine fuelled with diesel fuel and a biodiesel, namely cottonseed oil methyl ester (COME), subjected to preheating at different temperatures in order to lower its viscosity have been investigated.
155 citations
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03 Apr 2006TL;DR: In this article, the authors investigated the possibilities for extending the range of engine loads in which soot and NOx emissions can be minimised by using low temperature combustion in conjunction with high levels of EGR.
Abstract: The possibilities for extending the range of engine loads in which soot and NOx emissions can be minimised by using low temperature combustion in conjunction with high levels of EGR was investigated in a series of experiments with a single cylinder research engine. The results show that very low levels of both soot and NOx emissions can be achieved at engine loads up to 50 % by reducing the compression ratio to 14 and applying high levels of EGR (up to approximately 60 %). Unfortunately, the low temperature combustion is accompanied by increases in fuel consumption and emissions of both HC and CO. However, these drawbacks can be reduced by advancing the injection timing. The research engine was a 2 litre direct injected (DI), supercharged, heavy duty, single cylinder diesel engine with a geometry based on Volvo's 12 litre engine, and the amount of EGR was increased by adjusting the exhaust back pressure while keeping the charge air pressure constant.
155 citations