Yin Nan Yuan

Study on the Cooling System of Super-Capacitors for Hybrid Electric Vehicle

The heating mechanism of the capacitor is researched, the air cooling structure is designed of the capacitors, the model of the cooling of the capacitors is established for the heating phenomenon occurs during the charging and discharging process for super capacitors in series of hybrid electric vehicle. The model of the cooling is simulated based on the software of Star CCM +. The results of experiment show that the maximum temperature difference is less than 5°C among the capacitors, which ensures the consistency of the capacitors working temperature and proves the capacitors work substantially well.

Ignition Quality of Biodiesel from Cottonseed and Soybean Oil

The thermal analysis has been employed to yield information on the biodiesel ignition quality since the ignition quality influences the combustion and exhaust emissions of the fuels in a compression ignition (CI) engine. The chemical compositions of -10 petrodiesel (-10PD), soybean-based biodiesel (SME) and cottonseed-based biodiesel (CME) are analyzed by gas chromatography-mass spectrometry (GC-MS). Ignition temperature of -10PD, SME and CME is determined by thermogravimetry-differential scanning calorimetry (TG-DSC). The study shows that the biodiesel is mainly composed of fatty acid methyl esters: C14:0–C24:0, C16:1–C22:1, C18:2 and C18:3. Biodiesel ignition quality is better than petrodiesel. The ignition temperature of CME and SME is 207.4 and 213.9 °C respectively. The ignition quality of biodiesel is better with shorter carbon chain lengths and more saturated fatty acid methyl ester (SFAME).

Improving the Cold Flow Properties of Biodiesel Derived from Palm

The chemical compositions of biodiesel derived from palm (PME) were analyzed by gas chromatography-mass spectrometry (GC-MS). The cold flow properties of PME were studied by multifunctional low temperature tester, differential scanning calorimetry (DSC) and solution crystallization theory. Three approaches for improving cold flow properties of PME were put forward: crystallization fractionation, blending with winter petrodiesel and treating with cold flow improver (CFI) additives. A good correlation model was proposed for prediction cold filter plugging point (CFPP) by winter petrodiesel blending ratio. The study shows that the PME was mainly composed of saturated fatty acid methyl esters (SFAME): C14:0-C24:0 and unsaturated fatty acid methyl esters (UFAME): C16:1-C22:1, C18:2 and C18:3. The mass fraction of SFAME and UFAME was 35.86% and 62.83%, respectively. The CFPP of PME was 8°C. Crystallization fractionation and blending with -10 petrodiesel (-10PD) decreased the CFPP to 0 and -12°C, respectively. Treating with CFI additives (volume fraction ≤ 1.5%) decreased the CFPP of PME and PME/-10PD to 2 and -26°C, respectively. This study has effectively improved cold flow properties of PME and provided theoretical support for using PME during cold weather.

Simulation Research of the Effect of Compression Ratios on Combustion and Emission for Methanol/Diesel Dual Fuel Engine

This paper has studied the influence of the different ratio on combustion process and emissions of air premixed methanol/diesel dual fuel engine. The research was based on 4B26 diesel engine, and the 3-D numerical simulation on combustion process and emissions of the diesel engine with intake premixed methanol was carried out using AVL FIRE software. The study showed that,with the compression ratio reducing,the ignition delay period prolonged, and the ignition timing delayed, the maximum firing pressure, the peak of pressure rise rate and the maximum combustion temperature in cylinder decreased, the crank angle postponed, the NOX emission decreased and the Soot emission increased obviously.

Research Status of Key Technologies of Seamless Switching in Micro-Grid

In allusion to the stability of transferring between grid-connected and off-grid state in micro-grid, this paper introduces the seamless switching technology, analyzes the key technologies of seamless switching and the existing problems, and gets the conclusion about research status of seamless switching.

Current Research of Biodiesel Used on IC Engine and Improved Measures of Emissions

The emission mechanism of biodiesel used on IC engine is analyzed, as well as the summary of the research of domestic and abroad situation about biodiesel used on IC engine. The improved measures, which is under the premise of not affecting power performance and economic efficiency of IC engine, combining the emission process of IC engine was presented, it needs some measures to improve the quality of biodiesel and the system of IC engine to control the emission of the harmful substances, in this way the problem of energy shortage and environmental pollution can be ameliorated.

Current Situation of the Study on Oxidative Stability of Biodiesel

As a high quality alternative of fossil diesel, biodiesel is widely concerned at domestic and abroad for its environmentally friendly and renewable. Oxidation stability is one of the important properties of biodiesel, which is also one of the quality criteria in storing and using. The oxidative mechanism and the influencing factors of Oxidation stability, oxidation stabilitys evaluation methods and the application of biodiesel antioxidants were reviewed. Then the direction of oxidation stability is put forward.

Modeling of Biodiesel Cold Filter Plugging Point from their Chemical Composition

This paper studies the chemical composition of biodiesel, cold flow properties, and the influence of chemical composition on cold filter plugging point (CFPP) by using GC-MS and CFPP tester according to the theories of crystallization. Using the method of multivariate linear regression to analyze the correlation between chemical composition and CFPP, the prediction model of CFPP which has a very significant linear correlation and is based on chemical composition is built. The study shows that biodiesel is mainly fatty acid methyl ester (FAME) that is composed of 14-24 even number carbon atoms (C14:0~C24:0 , C16:1~C22:1, C18:2~C20:2 and C18:3). The CFPP increases linearly with the increase of the content of SFAME and the longer the carbon chains are, the greater the increase will be; the CFPP decreases linearly with the increase of the content of UFAME. Among the 120 kinds of biodiesel we studied, the CFPP of Chinese tallow methyl ester (CTME) is the lowest (-14 °C) and the CFPP of peanut methyl ester (PNME) is the highest (13 °C).

Prediction of the Cold Flow Properties in Biodiesel Blends

The chemical compositions of biodiesel are analyzed by GC-MS, and their molecular structures are investigated on the basis of the hybrid orbital theory. The CFPP of biodiesel is studied by CFPP tester, the solution crystallization theory and the similarity-intermiscibility principle. Good correlation models are proposed for predict CFPP of biodiesel by chemical compositions and the CFPP of biodiesel-petrodiesel blends by biodiesel ratio. The study shows that biodiesel is mainly composed of SFAME (C14:0～C24:0) and UFAME (C16:1～C22:1, C18:2 and C18:3 ). Carbon atoms of the alkyl for SFAME arrange in a zigzag pattern by ∠CCC=109.5°. C-C carbon atoms of the alkenyl arrange in a zigzag pattern by ∠CCC=109.5°, too, carbon chain is curved by C=C in ∠CCC=122.0°, and curved degree increases with increasing unsaturated degree. CFPP of biodiesel is mainly determined by chemical compositions. CFPP increases with the amount and carbon chain length of SFAME. CFPP of biodiesel-petrodiesel blends is mainly determined by chemical compositions and ratio of biodiesel. To lower SFAME≥C20:0 biodiesel, such as PME, CSME, WME, SBME and RME, it blending with -10PD can formed a eutectic mixture. CFPP of the eutectic mixture is -12 °C. The biodiesel ratio for the lowest CFPP rang increases with decreasing SFAME. Such as SFAME contents in PME, CSME, WME, SBME and RME are 35.86、32.12、31.04、18.29 and 14.69 w% respectively, and the range of biodiesel ratio is 5～20、10～20、20～30、30～50 and 40～60 v% respectively. To higher SFAME≥C20:0 biodiesel, such as PNME, CFPP increases with PNME ratio.

Combustion Characteristics of Biodiesel Derived from Palm and Rapeseed Oil

The chemical composition of palm and rapeseed biodiesel (fatty acid methyl ester, FAME) was analyzed by gas chromatography-mass spectrometry. Combustion characteristics of biodiesel were studied by thermogravimetry-differential scanning calorimetry and collision theory. Combustion characteristic index C was put forward for describing biodiesel combustion characteristic. The reactive atom combustion mechanism was put forward. Biodiesel combustion process comprised three steps, viz., volatilizing, dissociating and combining. First, biodiesel volatilizes, viz., FAME (liquid) volatilize and became FAME (gas). Second, FAME, O2 and N2 molecular were dissociated into C*, H*, O* and N* reactive atoms. Third, C*, H* and N* reacted, respectively, with O* to CO2, CO, H2O and NOx, and released energy. The study showed that the biodiesel was mainly composed of FAME: C14:0-C24:0, C16:1-C22:1, C18:2 and C18:3. Biodiesel had a good burnability. Combustion characteristic indexes of palm methyl ester (PME) and rapeseed methyl ester (RME) were 4.97E-05 and 3.65E-05, respectively. The combustion characteristic had relation to chemical composition. The combustion characteristic of biodiesel was better with increasing saturated fatty acid methyl esters and length of carbon-chain, and was poorer with increasing unsaturated fatty acid methyl esters and unsaturated degree. The combustion characteristic of PME was better than that of RME.