你好,我叫甲壳虫Beetle,a vehicle

正甲壳虫,它到底是一款怎样的车?它的出现为什么会改变人们对于家用车的认知呢?还有它为什么被称为甲壳虫呢?甲壳虫的最终成型,离不开一个人,他正是二十世纪最著名的法西斯独裁者——阿道夫·希特勒。当他发现汽车对于一个国家和民众的重要意义,就这样他提出了让每个德国家庭都能拥有一辆汽车的"国民车"计划,要求其实很简单:车里可以乘坐两个成人和三个儿童、一箱油能够行驶约64km、能够在严寒的冬季正常使用,最     

Analysis of a special purpose vehicle’s behaviour after an edge drop-off onto a soft shoulder

The article concerns the dynamics of a four-axle 20 ton special purpose vehicle in the driver’s panicky defensive manoeuvre resulting from edge drop-off of wheels onto a soft shoulder. A calculation model in the PC-Crash software environment has been developed to include the complex mechanism of the soft soil response to the wheel movement. The analysis of the results indicates the danger manifested by strong wheels vibrations, instantaneous change of vehicle steerability characteristics and a high rate of increase of the yaw angle and vehicle pitch during braking with steered wheels turned. The calculations indicate an extremely adverse effect of the phase of vehicle oversteer which in the analysed motion of the vehicle lasts over 1.5 s. The calculations prove that in such a short time the driver has very little chance of any practical response to the non-typical behaviour of the vehicle which otherwise is, in general, understeered.     

Simulation of vertical dynamic vehicle–track interaction using a two-dimensional slab track model

The vertical dynamic interaction between a railway vehicle and a slab track is simulated in the time domain using an extended state-space vector approach in combination with a complex-valued modal superposition technique for the linear, time-invariant and two-dimensional track model. Wheel–rail contact forces, bending moments in the concrete panel and load distributions on the supporting foundation are evaluated. Two generic slab track models including one or two layers of concrete slabs are presented. The upper layer containing the discrete slab panels is described by decoupled beams of finite length, while the lower layer is a continuous beam. Both the rail and concrete layers are modelled using Rayleigh–Timoshenko beam theory. Rail receptances for the two slab track models are compared with the receptance of a traditional ballasted track. The described procedure is demonstrated by two application examples involving: (i) the periodic response due to the rail seat passing frequency as influenced by the vehicle speed and a foundation stiffness gradient and (ii) the transient response due to a local rail irregularity (dipped welded joint).     

China’s commercial vehicle market to witness a new round of development phase

China’s auto industry started in the commercial vehicle field and it kept giving impetus to the auto market until 2004. Statistics from the CAAM show that during the 1998 to 2004 period, the average annual growth rate of the field was 14.38 percent, high…     

Evaluation of a vehicle directional control with a fractional order PD<Superscript>μ</Superscript> controller

In this paper, a novel controller, the fractional order PD^μ controller, is designed to improve the performance of the driver-vehicle system. First, fractional calculus and fractional order PI^λD^μ controller are introduced. A control algorithm for vehicle directional control using the fractional order PD^μ controller is then presented. Based on preview-follower theory, the on-line tuning method of the fractional order PD^μ controller is designed. By comparing simulated and experimental results, the validity and robustness of the proposed fractional order PD^μ controller in the closed loop system are verified. Finally, comprehensive evaluations are performed between the systems with the fractional order PD^μ controller and with an integer PD controller. The results demonstrate that the use of the fractional order controller leads to an improvement of the performance of the driver-vehicle system.     

Major vehicle models introduced in China

┏━━━━━━┳━━┳━━━━━━┳━━━━━━━━┳━━━━━┳━━━━━┳━━━━━┳━━━━━┳━━━━┳━━━━━┓┃蜘 ┃ ┃ 童零 ┃ 量 ┃ 謇 ┃ 量 ┃ I ┃ 昌 ┃ 重 ┃ 重 ┃┃ ┃ ┃ 星l ┃ 菩 ┃ 吾 ┃ 矗 ┃ ┃ n ┃ 心 ┃ G ┃┃ ┃ ┃ 墨亏 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃┣━━━━━━┫ ┣━━━━━━╋━━━━━━━━╋━━━━━╋━━━━━╋━━━━━╋━━━━━╋━━━━╋━━━━━┫┃ ┃ ┃ ┃ In ┃ ┃ ┃ ┃ ┃ ┃ ┃┃\ ┃ ┃ ┃ n ┃ ┃ ┃ ┃ ┃ ┃ ● ┃┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ● ┃…     

Fundamentals of vehicle–track coupled dynamics

This paper presents a framework to investigate the dynamics of overall vehicle–track systems with emphasis on theoretical modelling, numerical simulation and experimental validation. A three-dimensional vehicle–track coupled dynamics model is developed in which a typical railway passenger vehicle is modelled as a 35-degree-of-freedom multi-body system. A traditional ballasted track is modelled as two parallel continuous beams supported by a discrete-elastic foundation of three layers with sleepers and ballasts included. The non-ballasted slab track is modelled as two parallel continuous beams supported by a series of elastic rectangle plates on a viscoelastic foundation. The vehicle subsystem and the track subsystem are coupled through a wheel–rail spatial coupling model that considers rail vibrations in vertical, lateral and torsional directions. Random track irregularities expressed by track spectra are considered as system excitations by means of a time–frequency transformation technique. A fast explicit integration method is applied to solve the large nonlinear equations of motion of the system in the time domain. A computer program named TTISIM is developed to predict the vertical and lateral dynamic responses of the vehicle–track coupled system. The theoretical model is validated by full-scale field experiments, including the speed-up test on the Beijing–Qinhuangdao line and the high-speed running test on the Qinhuangdao–Shenyang line. Differences in the dynamic responses analysed by the vehicle–track coupled dynamics and by the classical vehicle dynamics are ascertained in the case of vehicles passing through curved tracks.     

Computational model for analyzing the kinematics and compliance characteristics of a commercial vehicle’s front suspension system

This paper develops a computational model that can analyze the kinematics and compliance characteristics of the front suspension of a commercial vehicle. This computational model is called the flexible multi-body dynamic model because it is developed by interfacing the finite element model of the multi-leaf spring with the dynamic model of the front suspension. In this paper, the bump mode and roll mode tests are performed with a suspension parameter measuring device (SPMD). An excitation load for creating the bump mode and roll mode motion is applied on the left and right tires slowly in in-phase and out-of-phase modes. In the test, wheel rate, toe angle change, caster angle change, and camber angle change, which together represent the wheel alignment, are measured along with the longitudinal and lateral wheel center loci which together represent the wheel center trajectory change. The reliability of the developed computational model is verified by comparing the simulation results with the SPMD test results. The developed flexible multi-body computational model will provide useful information on kinematics and compliance characteristics in the earliest stages of the commercial vehicle design process.     

Import and export of complete vehicle, 1998

┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┳━━━━━━━━━━━━┳━━━━━━━━━━━━━━━━━━━┓┃ ┃ Ouant~ty,unit ┃ Amount,USS ┃┃ Product ┃ ┃ ┃┃ ┣━━━━━━┳━━━━━╋━━━━━━━━━┳━━━━━━━━━┫┃ ┃ Import ┃ Export ┃ Import ┃ Export ┃┣━━━━━━━━━━━━━┳━━━━━━┳━━━━━━━━━━━━━╋━━━━━━╋━━━━━╋━━━━━━━━━╋━━━━━━━━━┫┃ ┃ ┃ seat≥30 ┃ 757 ┃ 30C ┃ 29。021.923 …     

What the vehicle purchase direction indicator tells us

Trends in the way people buy vehicles are like fashion colours-hard to master. But among all the uncertainties, one thing is unchangeable---brand power.     

Development of yonden electric vehicle “PIVOT”

A project was carried out to develop an appealing new electric vehicle that features those dynamic capabilities, including such universal drive as point rotation and lateral drive, which cannot be achieved by conventional engine-powered vehicles. The new electric vehicle, called “PIVOT”, was realized through the development of special steering and suspension systems that can steer each wheel at an angle wider than 90 degrees either way, the development of a control unit that can separately control the traction force and steer angles for each wheel, and the use of drive unit with motor-in-the-wheel systems.     

The status quo of special vehicle sector in China

I. Definitions of special vehicles (SP) and retrofitted-vehicles The special vehicles in China are mainly fabricated by the so-called retrofitters. That is because in the management method in the past, vehicle manufacturers are classified into producers and retrofitters in terms of production power and whether the vehicles are reprocessed on the chassis made by other producers. Vehicle production enterprises refer to those who are qualified of development, OEM supplying, production capability and can produce complete vehicles one time. Retrofitters refer to those who mainly conduct reprocessing on purchased chassis for making complete vehicles.     

High-frequency random vibration analysis of a high-speed vehicle–track system with the frequency-dependent dynamic properties of rail pads using a hybrid SEM–SM method

A hybrid Spectral Element Method (SEM)–Symplectic Method(SM) method for high-efficiency computation of the high-frequency random vibrations of a high-speed vehicle–track system with the frequency-dependent dynamic properties of rail pads is presented. First, the Williams-Landel-Ferry (WLF) formula and Fractional Derivative Zener (FDZ) model were, respectively, applied for prediction and representation of the frequency-dependent dynamic properties of Vossloh 300 rail pads frequently used in China's high-speed railway. Then, the proposed hybrid SEM–SM method was used to investigate the influence of the frequency-dependent dynamic performance of Vossloh 300 rail pads on the high-frequency random vibrations of high-speed vehicle–track systems at various train speeds or different levels of rail surface roughness. The experimental results indicate that the storage stiffness and loss factors of Vossloh 300 rail pad increase with the decrease in dynamic loads or the increase in preloads within 0.1–10,000?Hz at 20°C, and basically linearly increase with frequency in a logarithmic coordinate system. The results computed by the hybrid SEM–SM method demonstrate that the frequency-dependent viscous damping of Vossloh 300 rail pads, compared with its constant viscous damping and frequency-dependent stiffness, has a much more conspicuous influence on the medium-frequency (i.e. 20–63?Hz) random vibrations of car bodies and rail fasteners, and on the mid- (i.e. 20–63?Hz) and high-frequency (i.e. 630–1250?Hz) random vibrations of bogies, wheels and rails, especially with the increase in train speeds or the deterioration of rail surface roughness. The two sensitive frequency bands can also be validated by frequency response function (FRF) analysis of the proposed infinite rail–fastener model. The mid and high frequencies influenced by the frequency-dependent viscous damping of rail pads are exactly the dominant frequencies of ground vibration acceleration and wheel rolling noise caused by high-speed railways, respectively. Even though the existing time-domain (or frequency-domain) finite track models associated with the time-domain (or frequency-domain) fractional derivative viscoelastic (FDV) models of rail pads can also be used to reach the same conclusions, the hybrid SEM–SM method in which only one element is required to compute the high-order vibration modes of infinite rail is more appropriate for high-efficiency analysis of the high-frequency random vibrations of high-speed vehicle–track systems.     

Research on exhaust emission control characteristics of a natural gas vehicle — Characteristics of methane oxidation reaction of three-way catalysts

Model gas reaction experiments were conducted to analyze the factors causing the conversion rate of hydrocarbons (consisting mainly of CH₄) to decline in the lean-mixture region, using a natural gas engine fitted with a three-way catalyst. The results showed that there was no decline in the conversion rate of methane in CH₄-O₂ reactions in the lean-mixture region. However, it was observed that oxidation of CH₄ was suppressed when either H₂O or NO was also present. It is thought that prior adsorption of H₂O and NO inhibits adsorption of CH₄ at active sites, resulting in a lower conversion rate.     

A prediction on each segmented commercial vehicle market in 2007

Heavy truck The market trend has recovered since May 2006 and it reported a year on year growth of 30.55 percent by the end of Dec. The result was partly due to the heavy fall in the second half of 2005.     

Run-off-road and recovery – state estimation and vehicle control strategies

Despite many advances in vehicle safety technology, traffic fatalities remain a devastating burden on society. With over two-thirds of all fatal single-vehicle crashes occurring off the roadway, run-off-road (ROR) crashes have become the focus of much roadway safety research. Current countermeasures, including roadway infrastructure modifications and some on-board vehicle safety systems, remain limited in their approach as they do not directly address the critical factor of driver behaviour. It has been shown that ROR crashes are often the result of poor driver performance leading up to the crash. In this study, the performance of two control algorithms, sliding control and linear quadratic control, was investigated for use in an autonomous ROR vehicle recovery system. The two controllers were simulated amongst a variety of ROR conditions where typical driver performance was inadequate to safely operate the vehicle. The sliding controller recovered the fastest within the nominal conditions but exhibited large variability in performance amongst the more extreme ROR scenarios. Despite some small sacrifices in lateral error and yaw rate, the linear quadratic controller demonstrated a higher level of consistency and stability amongst the various conditions examined. Overall, the linear quadratic controller recovered the vehicle 25% faster than the sliding controller while using 70% less steering, which combined with its robust performance, indicates its high potential as an autonomous ROR countermeasure.     

A path-following driver–vehicle model with neuromuscular dynamics,including measured and simulated responses to a step in steering angle overlay

An existing driver–vehicle model with neuromuscular dynamics is improved in the areas of cognitive delay, intrinsic muscle dynamics and alpha–gamma co-activation. The model is used to investigate the influence of steering torque feedback and neuromuscular dynamics on the vehicle response to lateral force disturbances. When steering torque feedback is present, it is found that the longitudinal position of the lateral disturbance has a significant influence on whether the driver’s reflex response reinforces or attenuates the effect of the disturbance. The response to angle and torque overlay inputs to the steering system is also investigated. The presence of the steering torque feedback reduced the disturbing effect of torque overlay and angle overlay inputs. Reflex action reduced the disturbing effect of a torque overlay input, but increased the disturbing effect of an angle overlay input. Experiments on a driving simulator showed that measured handwheel angle response to an angle overlay input was consistent with the response predicted by the model with reflex action. However, there was significant intra- and inter-subject variability. The results highlight the significance of a driver’s neuromuscular dynamics in determining the vehicle response to disturbances.     

Motor vehicle imports by country and region, Jan-Jun, 1999

┏━━━━━┳━━━━┳━━━━┳━━━━┳━━━━┳━━━━┳━━━┳━━━━┳━━━━┳━━┳━━━┳━━┳━━┳━━━┳━━━┳━━━┳━━━━┳━━━┳━━━━┳━━━┳━━━┳━━━┳━━━┳━━━┳━━━┳━━━┳━━━┓┃ 若 ┃苗 ┃n ┃ ┃ ┃导 ┃昌 ┃ ┃ ┃ n ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃晷 ┃ ┃ ┃ ┃┃ ┃ ┃窨 ┃ ┃ ┃t ┃鬯 ┃ ┃ ┃文 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃┃ 嘻 ┃弓 ┃窨 ┃ ┃ ┃高 ┃口 ┃ ┃ ┃宝 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ …     

Motor vehicle exports by country and region, Jan-Jun, 1999

┏━━━━┳━━━━┳━━━┳━━━┳━━━┳━━┳━━┳━━━┳━━━┳━━━┳━━━┳━━━┳━━━┳━━┳━━━┳━━┳━━━━┳━━━┳━━┳━━━┳━━━┳━━┳━━┳━━┳━━┳━━┳━━━┳━━┳━━━┳━━┳━━━┳━━┳━━┳━━┳━━┳━━┳━━┓┃ ┃* ┃毯 ┃ ┃善 ┃ ┃ ┃ ┃ ┃ ┃0 ┃ ┃ ┃ N ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃0 ┃ 0 ┃ 0 ┃ ┃ ┃ ┃ ┃ ┃ 0 ┃ ┃ ┃ ┃┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃逭 ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃ ┃…