奇瑞汽车成本控制模式

本文的研究对象是奇瑞汽车股份有限公司。通过对奇瑞汽车现有成本控制体系进行分析,总结奇瑞汽车成本控制的优点;并主要针对奇瑞目前在成本控制方面存在的问题,对今后成本控制体系的进一步完善和提高提出了设想和建议。     

Ergonomics modelling and evaluation of automobile seat comfort

Automobile seats are developed in an iterative manner because subjective feedback, which is usually of questionable quality, drives the design. The time and cost associated with iteration could be justified if the process was guaranteed to produce a comfortable seat. Unfortunately, this is not the case. Current practices are based on the premise that seat system design teams need objective, measurable laboratory standards, which can be linked to subjective perceptions of comfort. Only in this way can predictions be made regarding whether or not a particular design will be viewed by the consumer as comfortable. This type of forecasting ability would effectively improve the efficiency with which automobile seats are designed. In this context, the research reported, developed, and validated a stepwise, multiple linear regression model relating seat interface pressure characteristics, occupant anthropometry, occupant demographics, and perceptions of seat appearance to an overall, subjective comfort index derived from a survey with proven levels of reliability and validity. The model performance statistics were: adjusted r ²?=?0.668, standard error of estimate?=?2.308, F (6, 38)?=?15.728, p?=?0.000, and cross-validated r (15)?=?0.952, p?=?0.000. From the model, human criteria for seat interface pressure measures were established. These findings could not have been attained without first demonstrating that (1) the data collection protocol for seat interface pressure measurement was repeatable and (2) seat interface pressure measurements can be used to distinguish between seats.     

一种基于防汽车追尾的车载测距安全预警装置的研制

介绍了激光雷达测距原理，进而引入到测距系统中，构建了一车载测距预警系统，分析了系统核心模块的组成和基本原理并给出了程序框图。当车间距达到阈值时及时发出声光与语音信号，提醒司机注意，避免追尾事故的发生。     

Instability of automotive air conditioning system with a variable displacement compressor. Part 2. Numerical simulation

A test system is built first in order to investigate the instability of the automotive air conditioning (AAC) system with a variable displacement compressor (VDC), and hunting phenomena caused by the large external disturbance in the AAC system with a VDC and a thermal expansion valve, and in the AAC system with a VDC and a fixed-area throttling device are investigated experimentally in part 1 of this paper. The experimental results indicate that there also exist the hunting phenomena in the AAC system with a fixed-area throttling device. The system stability is found to be dependent on the direction of the external disturbance, and the system is apt to cause hunting when the condensing pressure decreases excessively since it may cause two-phase state at the throttling device inlet and make a large disturbance to the system. The piston stroke length will oscillate only when the oscillation amplitudes of forces acting on the wobble plate are great enough, otherwise the piston stroke length will be kept invariable, and then the system instability rule is also suitable for the AAC system with a fixed displacement compressor. From the experimental results, it is concluded that the two-phase flow at the throttling device inlet or at the evaporator outlet is the necessary condition but not sufficient condition for system hunting. Finally, a new concept, conservative stable region, is proposed based on the experimental results and theoretical analysis.     

汽车衡称量管理系统设计与实现

汽车衡是大型企业广泛使用的称重仪器，本文叙述了汽车衡计算机称量管理系统设计与实现的一种方法，通过实行计算机管理，增加了重称系统的自动化程度，提高了称重的可靠性和准确性。     

BP神经网络预测全国私人汽车拥有量

利用前向多层神经网络的反向传播算法，即BP算法。采用MATLAB软件建立用于预测的BP神经网络(4-5-2)，将已知私人汽车拥有量对BP神经网络进行训练，建立私人汽车拥有量时间序列的预测模型，此BP神经网络可以成功对私人汽车拥有量进行预测计算。     

FTA在汽车可靠性设计中的应用

建造了ＨＦＣ１０６１汽车故障树，并详细阐述了万向传动装置故障树分析过程，以此来说明ＦＴＡ在汽车可靠性设计中的应用。     

Study of human–seat interface pressure distribution under vertical vibration

The influence of whole-body vertical vibration on the dynamic human–seat interface pressure is investigated using a flexible grid of pressure sensors. The ischium pressure and the overall pressure distribution at the human–seat interface are evaluated as functions of the magnitude and frequency of vibration excitation, and seated posture and height. The dynamic pressure at the seat surface is measured under sinusoidal vertical vibration of different magnitudes in the 1–10 Hz frequency range. Two methods based on ischium pressure and ischium force are proposed to study the influence of seat height, posture and characteristics of vibration. The results of the study reveal that the amplitude of dynamic pressure component increases with an increase in the excitation amplitude in almost entire frequency range considered in this study. The dynamic components of both the ischium pressure and the ischium force reveal peaks in the 4 to 5 Hz frequency band, the range of primary resonant frequency of the seated human body in the vertical mode. The mean values of the dynamic ischium pressure and the ischium force remain constant, irrespective of the excitation frequency and amplitude. The magnitudes of mean pressure and force at the human–seat interface, however, are dependent upon the seat height and the subject's posture. The inter-subject variability of the static ischium pressure and effective contact area are presented as functions of the subject weight and subject weight-to-height ratio. It was found that heavy subjects tend to induce low ischium pressure as a result of increased effective contact area.

Relevance to industry

Pressure distribution at the human–seat interface has been found to be an important factor affecting the seating comfort and work efficiency of various workers. The study of human–seat interface pressure distribution under vibration is specifically critical to the comfort, work efficiency and health of vehicle drivers, who are regularly exposed to vibration. The results reported in this paper will be useful to study dynamic response of the interface pressure and design vehicle seats.     

EPS系统模型的动态仿真研究

转向系统是汽车的重要组成部件，转向系统性能的好坏直接影响汽车的质量，而电动式转向系统(Electric Power Steering system)是当前转向系统发展的主要趋势，它不但具有传统转向系统的优点，还增强了转向灵活性、助力力矩调节灵活性，同时使结构更加紧凑。EPS的系统动态性能好坏是该系统成功与否的主要评价指标，该文正是围绕EPS系统的动态性能阐述了其工作原理，并建立了其动态特性的数学模型和系统仿真模型，基于此在计算机上用Matlab工具实现了EPS系统模型的动态仿真。     

CO2汽车空调用紧凑式换热器理论设计的探讨

紧凑式换热器的设计在很大程度上制约着CO2制冷剂在汽车空调制冷装置上的应用.本文从CO2汽车空调用紧凑式微通道换热器的换热量的估算和设计时理论限制等方面进行了讨论,指出微通道紧凑式换热器的传热机理,机械加工等的研究对工程设计和应用来讲还没有形成合适的技术指导依据,从理论上指出换热器尺寸、通道直径、数目、通道长度、换热效率以及泵功率之间是相互制约的.