JOURNAL OF BEIJING INSTITUTE OF TECHNOLOGY

Analytical Solution for Laminar Viscous Flow inthe Gap Between Two Parallel Rotary Disks

Liu Shuyan, Yan Weige

1998, 7(2): 113-119.

[Abstract](213) [PDF 334KB](6)

Abstract:
Aim To get the analytical for laminar viscous flow in the gap of two parallel rotating disks. Methods By estimating the order of magnitude of each term in the Navier-Stokes equations to drop small terms and achieve the required simplified differential equations, and by integrating the equations to obtain the solution for theflow between two rotary disks. Results Parameters related to the laminar viscous flow in the gap between two parallel rotary disks, such as the velocity, the pressure, the flowrate, the force, the shearing stress, the torque and the power derived. Conclusion The result provides a theoretical basis and an effective method for the designs of the devices connected with the laminar viscous flow in the gap between two parallel rotary disks.

Thermostability of Vane Absorber

Gu Liang, Qu Jinli, Ding Faqian

1998, 7(2): 120-128.

[Abstract](99)

Abstract:
Aim To improve the thermostability of vane absorbers while designing and manu- facturing. Methods Having considered the structural features of vane absorbers, measures that could reduce the force decay ratio of vane absorbers were discussed. A kind of practical auto temperature compensation apparatus, whose theoretical basis had been discussed, was designed. Results Compared to the prototype vane absorber, this kind of apparatus could decrease force decay ratio sharply. Thus, the thermostability of vane absorbers was improved greatly The accuracy of theoretical analysis and the effectiveness and feasibility of the apparatus was proved by actual testing Conclusion changing vane absorber's configuration, its performance is improved.

The Efficiency of Multi-Range Hydro-Mechanical Stepless Transmission

Yuan Shihua, HU Jibin

1998, 7(2): 129-134.

[Abstract](234)

Abstract:
Aim To determine efficiency of multi-range hydro-mechanical stepless transmis- sion(HMT).Methods Ageneral model of HMT was of HMT was structured.On the basis of power flow analysis, the efficiency was obtained,Results efficiency of multi-range HMT changes continuously with output speed in speed range and is higher than the highest point of the hydraulic efficiency,The volumetric efficiency can potentially result in the speed fluctuation, which can be reduced or eliminated through controlling the ratio of the displacements ofhydraulic unity properly or changing the point of range exchanging .And the mechanical- constant output torque or different output torque under the condition of constant pressure when the transmission works in different parts of a range,Conclusion The multi-range HMT is an ideal stepless transmission with high efficiency.

Analysis of Static Temperature Field of Vehicle's Solid Rubber Tire

Zheng Muqiao, Cui Yufu, Sun Fengchun

1998, 7(2): 135-140.

[Abstract](183)

Abstract:
Aim To analyse the static temperature field ofthe solid rubber tire(SRT).Methods The mechanical and thermal FE models were developed and analyzed respectively with the FE software ANSYS.Results The maximum temperature becomes higher with the higher with the higher velocity of tire and scales down slightly with the higher convection coefficients.The mixed models are reasonable.Conclusion The study on static temperature field is important and reasonable.It gives the fundament for life analysis of SRT.

New Math Model for Designing Engine Radiator

Huang Hongbin, Liu Shuyan, Zheng Shiqin, Yan Weige

1998, 7(2): 141-146.

[Abstract](202) [PDF 265KB](3)

Abstract:
Aim To raise the H-NE math model for designing engine radiators.Methods Thismodel was founded on multi-nonlinear regression technology,and the quadratic equatingmethod was used to smooth original data.Through the sensitivity analysis about radiatoroptimization designing,some major restraints were obtained.Results Type 1301C radiator wasoptimizingly renwed by use o this model,and the new radiator is more excellent than theold one in respect of the heat transfer factor and the manufacturing cost.Conclusion Theradiation performance can be improved,the area can be reduced,and the fitting scope can bewidened if this model is used in designing radiators.

Investigation on the Optimizing Range of CombustionChamber Configuration Parameters of DSCS

Li Xiangrong, Zhang Guodong, Wei Rong

1998, 7(2): 147-153.

[Abstract](167)

Abstract:
Aim To obtain an optimizing range of the main configuration parameters of double swirls combustion system (DSCS) Methods To analyze the influence of DS combustion cham-ber configuration parameters on fuel spray and mixing by means of the fuel jet developmentperiphery charts obtained by the high speed photography with a modeling test device deve-loped by authors,and to examine it by the tests on a single cylinder diesel engine.Resultsand Conclusion The mixing process can be divided into four phases.The optimizing range of the ration of the inner chamber diameter to the cylinder bore,d2/D,is 0.4-0.7; and the outerchamber diameter,d1 the height of the circular ridge to the piston top face,h1,the radius of outer/inner chamber circle,R1,R2 ,the max depth of outer/inner chamber bowl,H1,H2,etc. are also important

Study on Adaptive Shape Optimization

Zou Wensheng, Zuo Zhengxing, Fan Zhigang, Zhang Ruhua

1998, 7(2): 154-160.

[Abstract](226)

Abstract:
Aim To introduce a new method of adaptive shape optimization (ASOP) based on three-dimensional structure boundary strength and optimize an engine bearing cap with the method. Methods Using the normal substance's property of thermal expansion and cooling shrinkage,the load which is proportional to the difference between the nodes' stress and their respective objective stress were applied to the corresponding variable nodes on the boundary.The thermal load made the nodes whose stress is greater than their objective stress expand along the boundary's normal direction and the nodes whose stress is less than objec- tive stress shrink in the opposite direction , This process would repeat until the stress on the boundary nodes was converge to the objective stress. Results The satisfied results have been obtained when optimizing an engine bearing cap.The mass of the bearing cap is reduced to 55 percent of the total. Conclusion ASOP is an efficient,practical and reliable method which is suitable for optimizing the shape of the continuous structures.

Analysis of the Test of ER Fan Clutch

Zhang Shaohua, Wei Chenguan, Xia Guodong

1998, 7(2): 161-165.

[Abstract](183) [PDF 232KB](2)

Abstract:
Aim To carry out an experiment of the application of ER fluids in the clutch by reforming a fan clutch used in a truck. Methods At three different input rotating speeds,when the strength of applied electric field was changed, the output rotating speeds were recorded and analyzed. Results By comparing the results got under different experimental procedures with those measured with an electro-rheometer, it can be seen that the shearing rate has tremendous influence on the speed modulating of a fan clutch. This is because the disperse phase can't form chains (clusters)easily at high shear rate.Conclusion The result tested on the present ER fluid demonstrates that this fluid will show the properties of Newton one,i.e. its apparent viscosity is constant. as the shear rate increases.

Battery Management System with State ofCharge Indicator for Electric Vehicles

Sun Fengchun, Zhang Chengning, Guo Haitao

1998, 7(2): 166-171.

[Abstract](1022) [PDF 282KB](7)

Abstract:
Aim To research and develop a battery management system(BMS)with the state of charge(SOC)indicator for electric vehicles (EVs).Methods On the basis of analyzing the electro-chemical characteristics of lead-acid. battery, the state of charge indicator for lead-acid battery was developed by means of an algorithm based on combination of ampere-hour, Peukert's equation and open-voltage method with the compensation of temperature,aging,self- discharging,etc..Results The BMS based on this method can attain an accurate surplus capa- city whose error is less than 5% in static experiments.It is proved by experiments that the BMS is reliable and can give the driver an accurate surplus capacity,precisely monitor the individual battery modules as the same time,even detect and warn the problems early,and so on. Conclusion A BMS can make the energy of the storage batteries used efficiently, develop the batteries cycle life,and increase the driving distance of EVs.

Study on Blade Mould CAD/CAM for Hydrodynamic Torque COnverters

Xiang Changle, Yan Qingdong, LU Hongmei

1998, 7(2): 172-177.

[Abstract](218) [PDF 265KB](4)

Abstract:
Aim To develop blade mould CAD/CAM system of torque converter. Methods The mouldconsisted of four parts and an interactive computer program was developed to design a blade mould of torque converter based on UG at workstation. Results As compar- ed to manual modeling, it is showed in the application that this means not only improves the accuracy of blade shape and manufacture efficiency of converter, but also reduces costs. Conclusion It is proved that this CAD/CAM system is successful, and it opens up widely prospects for design and manufacture of the blade elementsand their moulds.

Automatic Control of Automobile Transmission Performance Test Stand

Yan Qingdong, Xiang Changle, Feng Yongcun

1998, 7(2): 178-183.

[Abstract](221)

Abstract:
To realize automatic control of automobile transmission performance test stand Methods The automatic control technique of the lubricant temperature,the program- controll- edautomaticshifting of the transmission,the continuous adjusting of revolution speed and load, data-acquisition and data real-time processing were adopted.Results The lubricant temperature was controlled at the set temperature ±2℃.The automatic shifting of the trans- mission is simple,reliable and accurate.The automatic adjusting of load and rotation speed is rapidandaccurate,the torque divergence is ±1N·m,the rotation speed divergence is ±5r/min Conclusion The four kinds of techniques are applied into the automobile transmission perfor- mance test stand successfully. mancetest stand successfully.

O-O Analysis of Vehicle Body Design and Establishment of Engineering Database

Chen Sizhong, Lin Leiming, Zhang Bin, Gu Zhongli

1998, 7(2): 184-189.

[Abstract](188)

Abstract:
To establish the object-oriented (O-O) engineering for vehicle body design Methods characteristics of vehicle body design data were analyzed by means of theO-Omethod The analytical results were transformed intothe engineering databasethat canbeusedsufficiently to describe the relative information of vehicle body design data.Results TheO-Oengineeringdatabaseforvehiclebodydesignis realized and practiced in the process ofbody design for a QCJ7082 economical car. Conclusion The method is successful in trans- forming vehicle body design object into engineering database.The database supports each procedure of vehicle body design perfectly

Investigation of Mechanical Stresses for Cylinder Head of High Power Diesel Engine

Zuo Zhengxing, Liao Ridong, Fan Lixia, Zou Wensheng

1998, 7(2): 190-195.

[Abstract](162)

Abstract:
Aim To ivestigate the influence on the cylinder head's stress distribution and value caused by its structure's changes.Methods Three types of cylinder heads of high power diesel engines were analysed with finite element method using I-DEAS Master series software.The actual condition of the cylinder head was simulated with different kinds of elements.Tempera- ture method was used to exert the predeformation of the bolts to the finite element model,so the pretightening force was discribed accurately Results Stress distribution regularities of the cylinder head under different working conditions were taken On the basis,the analysing results ofthreeof design schemes were compared and the optimum structure was taken Conclusion Transition condition between the head plate and the standing board ,shape of the head plate and the jobbing sheet,etc will affect the cylinder head's bearing condition

Multiple Purpose Simulation for Electric Vehicles

Yu Xiaojiang, Zhu Jiaguang

1998, 7(2): 196-202.

[Abstract](202)

Abstract:
Aim Toshorten integral design period of electric vehicles Methods The electric vehicle simulation program(EVSP), a modular user-friendly program which is written in Borland C++ OWL for Windows was developed. Results EVSP allows simulating the dynamic and the economy performance of electric vehicles.EVSP provides many kinds of data input module,a large components library of electric vehicles and several kinds of speed cycle with these library,it is easily to develop a new concept of different drive trains or even to compare or improve the existing electric vehicles. The paper simulated the performance of YW6120DD Electric Bus, and analyzed the test results comparing with simulation results Conclusion The simulation results indicate that the EVSP may contribute to the developments of electric vehicles in general and the definition of the optimal match management in the drive train in particular.

Noise Control of a Two Stroke Engine Car

Ge Yunshan, Wu Sijin, Liu Fushui, Zhang Fujun, Huang Ying

1998, 7(2): 203-209.

[Abstract](154)

Abstract:
Aim To control the noise of two stroke engine Methods On the basis of noise identification,a new muffler and acoustic shield were designed,Results the car's pass-by noise below the national limit Conclusion through proper noise controlling measures,the pass-by noise of two stroke engines could be reduced under national permitting limit.

1998 Vol. 7, No. 2