Simulation of mixed gas formation for a spray-wall complex guided LPG direct injection engine

To obtain an ultralean air-fuel ratio and to reduce engine-out NOX and HC emissions induced by the richer mixture near the spark plug, a spray and wall complex guided combustion system has been developed by utilizing the fuel characteristics of LPG. The new combustion system configuration is optimized by using a commercial CFD code, FIRE V2013, and the reliability of the system has been experimentally demonstrated by Plane Laser-Induced Fluorescence (PLIF). The mixture formation in the new combustion system under part load (2,000 rpm) is numerically simulated. With an injection timing of 40°CA BTDC, the LPG spray which is injected from two upper holes, reaches the ignition point, and the other part of the LPG spray which is injected from the bottom hole, is directed to the ignition point through the vertical vortices at the same time. At the ignition timing of about 20°CA BTDC, the two-part mixtures have been shown to form a stable and richer stratified mixture around the ignition point, and the maximum global air-fuel ratio reaches to 60: 1.     

State estimation in roll dynamics for commercial vehicles

Accurate lateral load transfer estimation plays an important role in improving the performance of the active rollover prevention system equipped in commercial vehicles. This estimation depends on the accurate prediction of roll angles for both the sprung and the unsprung subsystems. This paper proposes a novel computational method for roll-angle estimation in commercial vehicles employing sensors which are already used in a vehicle dynamic control system without additional expensive measurement units. The estimation strategy integrates two blocks. The first block contains a sliding-mode observer which is responsible for calculating the lateral tyre forces, while in the second block, the Kalman filter estimates the roll angles of the sprung mass and those of axles in the truck. The validation is conducted through MATLAB/TruckSim co-simulation. Based on the comparison between the estimated results and the simulation results from TruckSim, it can be concluded that the proposed estimation method has a promising tracking performance with low computational cost and high convergence speed. This approach enables a low-cost solution for the rollover prevention in commercial vehicles.     

The Kalker book of tables for non-Hertzian contact of wheel and rail

A new regularisation of non-elliptical contact patches has been introduced, which enables building the look-up table called by us the Kalker book of tables for non-Hertzian contact (KBTNH), which is a fast creep force generator that can be used by multibody dynamics system simulation programs. The non-elliptical contact patch is regularised by a simple double-elliptical contact region (SDEC). The SDEC region is especially suitable for regularisation of contact patches obtained with approximate non-Hertzian methods for solving the normal contact problem of wheel and rail. The new regularisation is suitable for wheels and rails with any profiles, including worn profiles.

The paper describes the new procedure of regularisation of the non-elliptical contact patch, the structure of the Kalker book of tables, and parameterisation of the independent variables of the tables and creep forces.

A moderate volume Kalker book of tables for SDEC region suitable for simulation of modern running gears has been computed in co-simulation of Matlab and program CONTACT.

To access the creep forces of the Kalker book of tables, the linear interpolation has been applied.

The creep forces obtained from KBTNH have been compared to those obtained by program CONTACT and FASTSIM algorithm. FASTSIM has been applied on both the contact ellipse and the SDEC contact patch. The comparison shows that KBTNH is in good agreement with CONTACT for a wide range of creepage condition and shapes of the contact patch, whereas the use of FASTSIM on the elliptical patch and SDEC may lead to significant deviations from the reference CONTACT solutions.

The computational cost of calling creep forces from KBTNH has been estimated by comparing CPU time of FASTSIM and KBTNH. The KBTNH is 7.8–51 times faster than FASTSIM working on 36–256 discretisation elements, respectively.

In the example of application, the KBTNH has been applied for curving simulations and results compared with those obtained with the creep force generator employing the elliptical regularisation. The results significantly differ, especially in predicted creepages, because the elliptical regularisation neglects generation of the longitudinal creep force by spin creepage.     

基于发动机台架考核方法的气缸盖高周疲劳特性研究

依据发动机台架考核规范,运用疲劳强度理论,对某铸铁气缸盖进行高周疲劳强度评估。明确温度和应力随考核工况改变的变化行为,研究气缸盖各区域受工作载荷的影响状况,为缸盖寿命评估模型提供载荷边界。结合疲劳理论,在考虑材料修正的基础上进行了疲劳特性分析和损伤状况分析。分析表明,气缸盖各区域的疲劳安全系数均大于1,视为安全,但冷却钻孔区域的安全裕度较小。     

小型直喷式柴油机燃用生物质能燃料的性能研究

文章主要研究了生物质能混合燃料在柴油机上的应用,通过在一台小型直喷式柴油机上进行不同组分柴油-生物柴油-乙醇混合燃料的燃烧、油耗和排放性能对比试验,分析了乙醇含量的改变对混合燃料的发动机燃烧压力、滞燃期、放热规律、比油耗和排放的影响．     

高速公路景观设计初探

就高速公路景观设计进行了探讨.     

高等级公路沥青路面平整度的控制

结合几年来的公路施工经验,根据影响路面平整度主要因素,分析设备及施工工艺方面应注意的主要事项,以提高高速公路路面的平整度.     

柴油机高压共轨电控燃油喷射技术

简要介绍柴油机电控高压共轨喷射系统的发展现状,主要分析柴油机电控高压共轨喷射系统的结构和原理,分析了柴油机电控高压共轨喷射系统的关键技术。     

Apoptin原核表达载体的构建及在大肠杆菌中的表达

目的构建Apoptin的原核表达载体,并制备抗原物质Apoptin融合蛋白。方法在获得Apoptin融合基因的基础上,成功构建了Apoptin的高效原核表达载体pET-28a( )-Apoptin,将该质粒转化至大肠杆菌E.coliBL21(DE3)受体菌中,以IPTG对其进行诱导表达,聚丙烯酰胺凝胶电泳分析目的蛋白。结果转化有Apoptin的原核表达载体pET-28a( )-Apoptin的大肠杆菌E.coliBL21(DE3)经IPTG诱导后,经SDS-PAGE分析,在相对分子质量约17 000的位置出现目的蛋白条带,大小与Apoptin融合蛋白一致。结论Apoptin原核表达载体pET-28a( )-Apoptin能够表达出Apoptin融合蛋白,为进一步的Apoptin研究和制备Apoptin抗体奠定了基础。