为改善乙醇-汽油发动机的燃烧和排放性能,针对一台乙醇-汽油发动机开展了典型工况下不同喷射策略的试验,对比分析了各种喷射策略和乙醇比例对发动机燃烧和排放的影响.结果表明,燃油消耗率(Brake Specific Fuel Consumption,BSFC)随加权...为改善乙醇-汽油发动机的燃烧和排放性能,针对一台乙醇-汽油发动机开展了典型工况下不同喷射策略的试验,对比分析了各种喷射策略和乙醇比例对发动机燃烧和排放的影响.结果表明,燃油消耗率(Brake Specific Fuel Consumption,BSFC)随加权喷射正时中心(T_(COI))提前呈现先下降而后趋于稳定,随喷射次数增加而下降.相比单次喷射,多次喷射使BSFC最大减少7%,一氧化碳和碳氢化合物排放明显降低,但会导致氮氧化物排放略有上升(远小于T_(COI)的影响).汽油掺混乙醇后,燃烧持续期变长,但由于点火正时和燃烧重心提前使发动机热效率明显提升.增大T_(COI)和乙醇比例均可降低一氧化碳体积分数,最大降幅达15%.乙醇比例对碳氢化合物和氮氧化物的影响取决于T_(COI).T_(COI)能很好地表征喷油特性,对排放影响比乙醇比例和喷射次数的影响均大.选取合适的喷射次数、乙醇比例和T_(COI)可显著提高发动机热效率并减少排放.展开更多
In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methan...In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methanol, 88% gasoline-12% ethanol and 88% gasoline-6% methanol-6% ethanol）. Additional tests are carried out with the basic gasoline fuel for comparison analysis and performance assessment. Engine performance is investigated under a variety of engine operating conditions. The results are presented in the domain of engine speed. In particular, the brake power of the engine is shown to be slightly increased. The brake thermal efficiency showed an increase compared with the basic gasoline engine. Similarly, it is shown that brake specific fuel consumption is enhanced compared with basic gasoline engine. The exhaust gas temperature showed a decrease compared with gasoline fuel which is preferable to reduce emissions. The alcohol additives are strongly recommended to enhance performance, increasing the mileage and reducing the emissions.展开更多
At the beginning of the tests on application of ethanol gasoline in 2001, Chinese government promulgated a national standard, GB 18351-2001 ＂Ethanol Gasoline for Motor Vehicles＂. The standard specifies three kinds o...At the beginning of the tests on application of ethanol gasoline in 2001, Chinese government promulgated a national standard, GB 18351-2001 ＂Ethanol Gasoline for Motor Vehicles＂. The standard specifies three kinds of ethanol gasoline, namely E10 （90 RON）, E10 （93 RON） and E10 （95 RON）. There were ethanol gasoline grades （90 RON and 93 RON） and conventional unleaded gasoline（97 RON） available in the areas where tests were carried out. Vehicle owners were worded about the harmful action of ethanol to their vehicles because of lack of knowledge regarding ethanol fuel, and they only refueled their cars with conventional 97 RON unleaded gasoline. This idea might cause unnecessary costs to customers and could bring about difficulty to the tests as well. Besides, some other technical questions emerged during the experimental application of ethanol gasoline, such as water content, ethanol content in gasoline, etc. Based on the experiences accumulated during the application tests, the national standard GB 18351-2001 ＂Ethanol Gasoline for Motor Vehicles＂ was revised. The revised edition is designated as GB 18351-2004.展开更多
The mechanical properties, thermal and gasohol resistance of the natural zeolite, rice husk ash （RHA） and perlite-filled natural rubber （NR） with addition of carbon black （CB） loading was studied. The amount of ...The mechanical properties, thermal and gasohol resistance of the natural zeolite, rice husk ash （RHA） and perlite-filled natural rubber （NR） with addition of carbon black （CB） loading was studied. The amount of fillers （natural zeolite, RHA and perlite） filled in the vulcanizates has been fixed at 20 phr, while CB loading was varied in a range of 0-45 phr. It was found that the tensile strength, percentage of elongation at break, modulus and hardness of the vulcanizates filled with all kinds of fillers increased with the increase of CB loading, while there was no significant change in the compression set. Moreover, at this particular filler loading （20 phr）, the addition of perlite has significant effect on gasohol resistance of the vulcanizates in which gasohol resistance （various ethanol ratio） of the vulcanizates was significantly improved with perlite loading compared with others.展开更多
The fuel dynamic transfer process,including fuel injection,fuel film deposition and evaporation in the intake port,was analyzed for spark ignition(SI) engines with port fuel injection(PFI).The influence of wall-wettin...The fuel dynamic transfer process,including fuel injection,fuel film deposition and evaporation in the intake port,was analyzed for spark ignition(SI) engines with port fuel injection(PFI).The influence of wall-wetting fuel film,especially its evaporation rate,upon the air-fuel ratio of in-cylinder mixtures was also discussed.According to the similarity principle,Fick's law,the ideal gas equation and the Gilliland correlation,an evaporate prediction model of wall-wetting fuel film was set up and an evaporate prediction based dynamic fuel film compensator was designed.Through engine cold start tests,the wall-wetting temperature,which is the key input of the fuel film evaporate prediction model,was also modeled and predicted.Combined with the experimental data of the evaporation characteristics of ethanol-gasoline blends and engine calibration tests,all the parameters of the wall-wetting fuel film evaporate prediction model used in the fuel film compensator were identified.Square-wave disturbance tests of fuel injection showed that with the help of the fuel film compensator the response of the in-cylinder air-fuel ratio was significantly improved and the real air-fuel ratio always closely matched the expected ratio.The fuel film compensator was then integrated into the final air-fuel ratio controller,and the engine tests showed that the air-fuel ratio control error was less than 2% in steady-state conditions,and less than 4% in transient conditions.The fuel film compensator also showed good adaptability to different ethanol-gasoline blends.展开更多
We demonstrated the application of sensors for ethanol gas detection.The ZnO nanowires based sensors with interdigital electrodes were fabricated,and a platform was constructed to test the properties of the sensors.To...We demonstrated the application of sensors for ethanol gas detection.The ZnO nanowires based sensors with interdigital electrodes were fabricated,and a platform was constructed to test the properties of the sensors.To acquire better response and shorter response/recovery time,the ZnO nanowires were modified with Au.The ethanol gas sensing performance of the pure sensors and those modified with Au nanoparticles were investigated for comparison,and the optimal test temperature of 350℃ was obtained.We found that the response/recovery time for the modified sensor towards 500 ppm of the ethanol gas was reduced by 1.35 and1.42 times compared with the pure sensors,and the sensitivities towards 500 and 10 ppm of the ethanol gas were also increased by 3.18 and 1.35 times,respectively.These proved the enhancement of the Au nanoparticles in the ZnO nanowires based sensors for ethanol gas sensing.展开更多
文摘为改善乙醇-汽油发动机的燃烧和排放性能,针对一台乙醇-汽油发动机开展了典型工况下不同喷射策略的试验,对比分析了各种喷射策略和乙醇比例对发动机燃烧和排放的影响.结果表明,燃油消耗率(Brake Specific Fuel Consumption,BSFC)随加权喷射正时中心(T_(COI))提前呈现先下降而后趋于稳定,随喷射次数增加而下降.相比单次喷射,多次喷射使BSFC最大减少7%,一氧化碳和碳氢化合物排放明显降低,但会导致氮氧化物排放略有上升(远小于T_(COI)的影响).汽油掺混乙醇后,燃烧持续期变长,但由于点火正时和燃烧重心提前使发动机热效率明显提升.增大T_(COI)和乙醇比例均可降低一氧化碳体积分数,最大降幅达15%.乙醇比例对碳氢化合物和氮氧化物的影响取决于T_(COI).T_(COI)能很好地表征喷油特性,对排放影响比乙醇比例和喷射次数的影响均大.选取合适的喷射次数、乙醇比例和T_(COI)可显著提高发动机热效率并减少排放.
文摘In this paper, experimental investigations are presented to assess the performance variations in a single cylinder spark ignited engine when run with three different gasoline-alcohol blends： （88% gasoline-12% methanol, 88% gasoline-12% ethanol and 88% gasoline-6% methanol-6% ethanol）. Additional tests are carried out with the basic gasoline fuel for comparison analysis and performance assessment. Engine performance is investigated under a variety of engine operating conditions. The results are presented in the domain of engine speed. In particular, the brake power of the engine is shown to be slightly increased. The brake thermal efficiency showed an increase compared with the basic gasoline engine. Similarly, it is shown that brake specific fuel consumption is enhanced compared with basic gasoline engine. The exhaust gas temperature showed a decrease compared with gasoline fuel which is preferable to reduce emissions. The alcohol additives are strongly recommended to enhance performance, increasing the mileage and reducing the emissions.
文摘At the beginning of the tests on application of ethanol gasoline in 2001, Chinese government promulgated a national standard, GB 18351-2001 ＂Ethanol Gasoline for Motor Vehicles＂. The standard specifies three kinds of ethanol gasoline, namely E10 （90 RON）, E10 （93 RON） and E10 （95 RON）. There were ethanol gasoline grades （90 RON and 93 RON） and conventional unleaded gasoline（97 RON） available in the areas where tests were carried out. Vehicle owners were worded about the harmful action of ethanol to their vehicles because of lack of knowledge regarding ethanol fuel, and they only refueled their cars with conventional 97 RON unleaded gasoline. This idea might cause unnecessary costs to customers and could bring about difficulty to the tests as well. Besides, some other technical questions emerged during the experimental application of ethanol gasoline, such as water content, ethanol content in gasoline, etc. Based on the experiences accumulated during the application tests, the national standard GB 18351-2001 ＂Ethanol Gasoline for Motor Vehicles＂ was revised. The revised edition is designated as GB 18351-2004.
文摘The mechanical properties, thermal and gasohol resistance of the natural zeolite, rice husk ash （RHA） and perlite-filled natural rubber （NR） with addition of carbon black （CB） loading was studied. The amount of fillers （natural zeolite, RHA and perlite） filled in the vulcanizates has been fixed at 20 phr, while CB loading was varied in a range of 0-45 phr. It was found that the tensile strength, percentage of elongation at break, modulus and hardness of the vulcanizates filled with all kinds of fillers increased with the increase of CB loading, while there was no significant change in the compression set. Moreover, at this particular filler loading （20 phr）, the addition of perlite has significant effect on gasohol resistance of the vulcanizates in which gasohol resistance （various ethanol ratio） of the vulcanizates was significantly improved with perlite loading compared with others.
基金Project (Nos. 51106136 and 50776078) supported by the National Natural Science Foundation of China
文摘The fuel dynamic transfer process,including fuel injection,fuel film deposition and evaporation in the intake port,was analyzed for spark ignition(SI) engines with port fuel injection(PFI).The influence of wall-wetting fuel film,especially its evaporation rate,upon the air-fuel ratio of in-cylinder mixtures was also discussed.According to the similarity principle,Fick's law,the ideal gas equation and the Gilliland correlation,an evaporate prediction model of wall-wetting fuel film was set up and an evaporate prediction based dynamic fuel film compensator was designed.Through engine cold start tests,the wall-wetting temperature,which is the key input of the fuel film evaporate prediction model,was also modeled and predicted.Combined with the experimental data of the evaporation characteristics of ethanol-gasoline blends and engine calibration tests,all the parameters of the wall-wetting fuel film evaporate prediction model used in the fuel film compensator were identified.Square-wave disturbance tests of fuel injection showed that with the help of the fuel film compensator the response of the in-cylinder air-fuel ratio was significantly improved and the real air-fuel ratio always closely matched the expected ratio.The fuel film compensator was then integrated into the final air-fuel ratio controller,and the engine tests showed that the air-fuel ratio control error was less than 2% in steady-state conditions,and less than 4% in transient conditions.The fuel film compensator also showed good adaptability to different ethanol-gasoline blends.
基金supported by the Program for Changjiang Scholars and Innovative Research Team in UniversityProgram for New Century Excellent Talents in UniversityNational Natural Science Foundation of China(Grant Nos.51305129 and 51222508)
文摘We demonstrated the application of sensors for ethanol gas detection.The ZnO nanowires based sensors with interdigital electrodes were fabricated,and a platform was constructed to test the properties of the sensors.To acquire better response and shorter response/recovery time,the ZnO nanowires were modified with Au.The ethanol gas sensing performance of the pure sensors and those modified with Au nanoparticles were investigated for comparison,and the optimal test temperature of 350℃ was obtained.We found that the response/recovery time for the modified sensor towards 500 ppm of the ethanol gas was reduced by 1.35 and1.42 times compared with the pure sensors,and the sensitivities towards 500 and 10 ppm of the ethanol gas were also increased by 3.18 and 1.35 times,respectively.These proved the enhancement of the Au nanoparticles in the ZnO nanowires based sensors for ethanol gas sensing.
