Predicting auto-ignition characteristics of RCCI combustion using a multi-zone model

The objective of new combustion concepts is to meet emission standards by improving fuel air mixing prior to ignition. Since there is no overlap between injection and ignition, combustion is governed mainly by chemical kinetics and it is challenging to control the phasing of ignition. Reactivity Controlled Compression Ignition (RCCI) combustion aims to control combustion phasing by altering the fuel ratios of the high- and low octane fuel and injection timings. In this study the dual fuel blend is prepared with gasoline and diesel fuels. The applied injection timings of the diesel are very early (90 to 60° CA bTDC). In the detailed reaction mechanism, n-heptane and iso-octane represent diesel and gasoline fuel, respectively. A multi-zone model approach is implemented to perform RCCI combustion simulation. Ignition characteristics are analyzed by using CA50 as the main parameter. In the experiments for the early direct injection (DI) timing advancing the injection time results in a later ignition. Qualitatively, the trend effect of the diesel injection timing and the effect of the ratio gasoline/diesel are captured accurately by the multi-zone model.     

Precise and reliable positioning based on the integration of navigation satellite system and vision system

In this paper, we propose a precise and reliable positioning method for solving common problems, such as a navigation satellite’s signal occlusion in an urban canyon and the positioning error due to a limited number of visible navigation satellites. This is an integrated system of the navigation satellites system and a vision system. In general, the navigation satellite positioning system has a fatal weakness in that it can not calculate a position coordinate when its signal is occluded by some obstacle. For this reason, positioning by using the navigation satellites system can not be used for a variety of applications. Therefore, we propose as a method to integrate both the navigation satellites system and the vision system. Some target objects that have accurate position coordinates, for example, in an outdoor shaded area like an urban canyon, are installed into the vision system. When the vision system recognizes a target object it loads the accurate coordinate of that target object. Then, it measures the distance by using the disparity from the camera sensor to the target object. These distance and object coordinate data are used for positioning with the navigation satellites system’s data. This integrated system can be used for the positioning solution where the user is in unfavorable conditions. This paper shows that the algorithm of integrated system and the numerical test performed. The results indicate that the reliable and stable positioning can be obtained by introducing the vision system to the satellite navigation system.     

Comparison of PMP and DP in fuel cell hybrid vehicles

Pontryagin’s Minimum Principle (PMP) and Dynamic Programming (DP) are both from the optimal control theory and can both achieve optimal trajectories when they are applied to power management strategies of hybrid vehicles. However they have totally different control concepts. In order to select the superior one, the PMP-based and the DP-based power management strategies are introduced and compared for a fuel cell hybrid vehicle (FCHV) in this paper. The two power management strategies are applied to the FCHV in a computer simulation environment, and the simulation results from the two strategies are compared when the control variable for the PMP is fuel cell system (FCS) net power and for the DP is battery power. As a result, the superiority of the PMP-based power management strategy is proved.     

Micro deformation of automobile hood in dipping process using stiffness

Technicians have been going through trial-and-error processes to solve very small or micro deformation on automobile hood during the painting process. In order to establish a systematic improvement procedure which can replace the time-consuming trial-and-error method to reduce defects, an accurate analysis of how micro deformation occurs during the painting process is needed. We have utilized a stiffness scanning method in automobile hood and reverse engineering to build up a reliable and accurate structural analysis and measurement procedures. We measured the load-stroke data at critical locations on automobile hood through stiffness scanning to determine material constants closest to the measurement by assuming several critical hood parts, such as sealer inside the hood, hemming part, spot weld part, and other uncertain joints, as virtual elastic materials. After setting the difference between analytical and measured load-stroke data as an objective function, we computed and minimized it by using the response surface method and partial differentiation of the object function. As a result, by obtaining the reliability was over 91%, which showed a strong correlation between analysis and measured results. By comparing the actual strain measured in real painting lines with calculated strain, we confirmed the validity of our structural analysis method. It was concluded that the proper analysis tool could be utilized in determination of optimal locations of supports during the painting process.     

Morphology and oxidation kinetics of CI engine’s biodiesel particulate matters on cordierite Diesel Particulate Filters using TGA

The impact of small compression ignition (CI) engine operation conditions and fuel properties on diesel and biodiesel particulate matters (PMs) quantity using opacity smoke meter is investigated. The biodiesel engine’s PMs are around a half of diesel engine PMs under the same engine operation conditions. Morphology of both engine’s PMs are also studied using a Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and image processing method. The average primary nanoparticle sizes of diesel and biodiesel engine’s PMs are approximately 34 nm and 32 nm, respectively. The result shows that engine operation condition and fuel property are strongly impact on the quantity and size distribution of primary nanoparticles emission. PM oxidation kinetics on conventional cordierite Diesel Particulate Filters (DPFs) powders by Thermo-gravimetric analysis (TGA) is also successfully studied. The calculated apparent activation energies of biodiesel engine’s PM oxidation on conventional cordierite DPFs powders are lower than that of diesel engine’s PM and carbon black because of unburned oxygenated molecule. The calculated apparent activation energy of biodiesel engine’s PM and diesel engine’s PM oxidize on conventional cordierite DPFs powders with pure air are in the range of 109 ~ 131 kJ/mole and 117 ~ 130 kJ/mole, respectively. It might be expected that smaller primary nanoparticle size of biodiesel engine’s PMs and bio-oxygenate unburned hydrocarbon can promote more PM oxidation rate during vehicle’s DPF regeneration process.     

Torque ripple minimization control of permanent magnet synchronous motors for EPS applications

This paper identifies a control method used to reduce torque ripple of a permanent magnet synchronous motor (PMSM) for an electric power steering (EPS) system. NVH (Noise Vibration Harshness) is important for safe and convenient driving. Vibration caused by motor torque is a problem in column type EPS systems. Maintaining a very low torque ripple is one solution that allows for smoother steering. Theoretically, it is possible to design and drive the motor without torque ripple. However, in reality, a PMSM system torque ripple is caused by the motor itself (saturation in the iron core and EMF distortion) and the imperfect driver. This paper analyzes torque ripple of a PMSM system, and an advanced PMSM control method for the column typed EPS system is presented. Results of the analysis indicate that the compensation current is needed in order to minimize torque ripple when a PMSM is driven.     

展望中国Telematics业务发展

中国汽车生产商们首先必须了解,哪些是消费者愿意花钱购买的Telematics服务,一味地模仿西方市场,是不够的。     

Development of a hydraulic limited slip differential system using a pressure generator

The limited slip differential (LSD) is a device that enables the driving force to be transmitted from one slipping wheel to the other by temporarily restraining the differential function when unwanted slipping occurs on muddy or icy roads. Many types of LSD have been developed, such as mechanical lock, disk clutch, viscous coupling, torsen and multiple clutch. This study designed a new type of hydraulic LSD using a pressure generator base on a trochoid gear pump and evaluated the performance of the new design.     

Finite element analysis of rotary blanking: Effects of punch geometries on cutting area and stress distribution

It is essential to develop efficient and cost-effective production methods to achieve or maintain international competitiveness. An innovative production method, such as rotary blanking, enables manufacturers to both reduce expenses and economize production time. However, there are not enough numerical analyses for this process. In this paper, numerical simulations of rotary blanking were performed. After comparing the cutting planes generated by conventional and rotary blanking experimental tests, the cutting areas of two punch geometries were analyzed. The influence of punch geometry on part quality was then investigated through simulations. The procedure for die stress analysis was established and stress distributions of the worksheet and the tools were analyzed.