The existing soot models are either too complex and can not be applied to the internal combustion engine, or too simple to make calculation errors. Exploring the soot model becomes the pursuit of the goal of many researchers within the error range in the current computer speed. On the basis of the latest experimental results, TP (temperature phases) model is presented as a new soot model to carry out optimization calculation for a high-pressure common rail diesel engine. Temperature and excess air factor are the most important two parameters in this model. When zone temperature T?1 500 K and excess air factor Ф?0.6, only the soot precursors-polycyclic aromatic hydrocarbons(PAH) is created and there is no soot emission. When zone temperature T ≥ 1 500 K and excess air factor Ф?0.6, PAHs and soot source terms (particle inception, surface growth, oxidation, coagulation) are calculated. The TP model is then implemented in KIVA code instead of original model to carry out optimizing. KIVA standard model and experimental data are analyzed for the results of cylinder pressures, the corresponding heat release rates, and soot with variation of injection time, variation of rail pressure and variation of speed among TP models. The experimental results indicate that the TP model can carry out optimization and computational fluid dynamics can be a tool to calculate for a high-pressure common rail directed injection diesel engine. The TP model result is closer than the use of the original KIVA-3V results of soot model accuracy by about 50% and TP model gives a new method for engine researchers.
For capturing and recycling of CO_2 in the internal combustion engine, Rankle cycle engine can reduce the exhaust pollutants effectively under the condition of ensuring the engine thermal efficiency by using the techniques of spraying water in the cylinder and optimizing the ignition advance angle. However, due to the water spray nozzle need to be installed on the cylinder, which increases the cylinder head design difficulty and makes the combustion conditions become more complicated. In this paper, a new method is presented to carry out the closing inlet and exhaust system for internal combustion engines. The proposed new method uses liquid oxygen to solidify part of cooled CO_2 from exhaust system into dry ice and the liquid oxygen turns into gas oxygen which is sent to inlet system. The other part of CO_2 is sent to inlet system and mixed with oxygen, which can reduce the oxygen-enriched combustion detonation tendency and make combustion stable. Computing grid of the IP52 FMI single-cylinder four-stroke gasoline-engine is established according to the actual shape of the combustion chamber using KIVA-3V program. The effects of exhaust gas recirculation(EGR) rate are analyzed on the temperatures, the pressures and the instantaneous heat release rates when the EGR rate is more than 8%. The possibility of enclosing intake and exhaust system for engine is verified. The carbon dioxide trapping device is designed and the IP52 FMI engine is transformed and the CO_2 capture experiment is carried out. The experimental results show that when the EGR rate is 36% for the optimum EGR rate. When the liquid oxygen of 35.80–437.40 g is imported into the device and last 1–20 min, respectively, 21.50–701.30 g dry ice is obtained. This research proposes a new design method which can capture CO_2 for vehicular internal combustion engine.
LIU YongfengJIA XiaoshePEI PuchengLU YongYI LiSHI Yan
