为提高柴油机的可靠性和标定工作效率,以某柴油机为试验对象,基于正交试验设计方法,研究最低油耗工况下喷油压力、喷油时刻、废气再循环(exhaust gas recirculation,EGR)阀开度3个因素对发动机爆发压力的影响,并通过计算极差与方差分析...为提高柴油机的可靠性和标定工作效率,以某柴油机为试验对象,基于正交试验设计方法,研究最低油耗工况下喷油压力、喷油时刻、废气再循环(exhaust gas recirculation,EGR)阀开度3个因素对发动机爆发压力的影响,并通过计算极差与方差分析影响因素的敏感性。结果表明:喷油压力由120 MPa增大到140 MPa,爆发压力增大1.04 MPa;提前角由上止点前曲轴转角8°增加到10°,爆发压力增大1.68 MPa;EGR阀开度由50%降低到30%,爆发压力增大0.55 MPa。3个因素对爆发压力的影响敏感性顺序为:喷油时刻、喷油压力、EGR阀开度。展开更多
对不同排气再循环(exhaust gas recirculation,EGR)系统对发动机性能的影响进行仿真分析。结果表明:单路EGR系统缩小涡轮尺寸可以产生较高EGR率,但是油耗较高;单向阀在涡轮尺寸较大时具有较好地提高EGR率的效果;与单EGR冷却器相比,两路...对不同排气再循环(exhaust gas recirculation,EGR)系统对发动机性能的影响进行仿真分析。结果表明:单路EGR系统缩小涡轮尺寸可以产生较高EGR率,但是油耗较高;单向阀在涡轮尺寸较大时具有较好地提高EGR率的效果;与单EGR冷却器相比,两路EGR系统双EGR冷却器具有提高EGR率的潜力;两路EGR系统+单向阀泵气损失小,EGR效率高且油耗低。展开更多
The study on toughening and reinforcing of bisphenol-A epoxy resin is one of important developmental direction in the field.This paper reports a one-pot synthesis of aromatic polyester hyperbranched epoxy resin HTDE-2...The study on toughening and reinforcing of bisphenol-A epoxy resin is one of important developmental direction in the field.This paper reports a one-pot synthesis of aromatic polyester hyperbranched epoxy resin HTDE-2,an effect of HTDE-2 content on the mechanical and thermal performance of the bisphenol-A(E51)/HTDE-2 hybrid resin in detail.Fourier transform infrared(FT-IR)spectrometer,scanning electronic microscopy(SEM),differential scanning calo ri metry(DSC),thermogravimetric analysis(TGA),dynamic mechanical thermal analysis(DMA)and molecular simula tion technology are used to study the structure of HTDE-2,performance and toughening and reinforcing mech-anism of the HTDE-2/E51 hybrid resin.It has been shown that the content of HTDE-2 has an important effect on the performance of the hybrid resin,and the performance of the HTDE-2/E51 blends has maximum with the increase in HTDE-2 content.The impact strength and fracture toughness of the hybrid resin with 9 wt-%HTDE-2 are almost 3.088 and 1.749 times of E51 performance respectively,furthermore,the tensile and flexural strength can also be enhanced about 20.7% and 14.2%,respectively.The glass transition tem-perature and thermal degradation temperature,however,are found to decrease to some extent.展开更多
文摘对不同排气再循环(exhaust gas recirculation,EGR)系统对发动机性能的影响进行仿真分析。结果表明:单路EGR系统缩小涡轮尺寸可以产生较高EGR率,但是油耗较高;单向阀在涡轮尺寸较大时具有较好地提高EGR率的效果;与单EGR冷却器相比,两路EGR系统双EGR冷却器具有提高EGR率的潜力;两路EGR系统+单向阀泵气损失小,EGR效率高且油耗低。
基金The authors gratefully acknowledge the finacial support of the National Natural Science Foundation of China(Grant No.50573021)the Natural Science Foundation of South-Central University for Nationalities,China(No.YZZ06012).
文摘The study on toughening and reinforcing of bisphenol-A epoxy resin is one of important developmental direction in the field.This paper reports a one-pot synthesis of aromatic polyester hyperbranched epoxy resin HTDE-2,an effect of HTDE-2 content on the mechanical and thermal performance of the bisphenol-A(E51)/HTDE-2 hybrid resin in detail.Fourier transform infrared(FT-IR)spectrometer,scanning electronic microscopy(SEM),differential scanning calo ri metry(DSC),thermogravimetric analysis(TGA),dynamic mechanical thermal analysis(DMA)and molecular simula tion technology are used to study the structure of HTDE-2,performance and toughening and reinforcing mech-anism of the HTDE-2/E51 hybrid resin.It has been shown that the content of HTDE-2 has an important effect on the performance of the hybrid resin,and the performance of the HTDE-2/E51 blends has maximum with the increase in HTDE-2 content.The impact strength and fracture toughness of the hybrid resin with 9 wt-%HTDE-2 are almost 3.088 and 1.749 times of E51 performance respectively,furthermore,the tensile and flexural strength can also be enhanced about 20.7% and 14.2%,respectively.The glass transition tem-perature and thermal degradation temperature,however,are found to decrease to some extent.
