基于ADAMS的轮式拖拉机行驶平顺性研究

基于Pro/E软件平台,构建拖拉机-座椅悬架系统简化的几何模型,并将其导入ADAMS软件,编写轮胎属性文件与路面激励文件,构建拖拉机-座椅-路面系统的虚拟样机。针对不同的行驶速度与路面激励,对拖拉机的行驶平顺性进行仿真分析,探究行驶速度与路面激励对拖拉机平顺性的影响。结果表明,行驶速度与路面激励不平度对拖拉机行驶平顺性具有重要影响,以较高车速行驶时,驾驶员垂直方向振动强度明显高于较低车速的振动强度;在粗糙路面上行驶时,驾驶员的主观振动感明显强于平坦路面的振动感。增设座椅悬架系统改进拖拉机座椅结构,探究增设座椅悬架系统对行驶平顺性的影响,结果表明,增设座椅悬架系统可以明显降低其垂直方向的振动幅度,避开人体内脏器官和脊椎系统振动敏感频率区域,提高拖拉机行驶的平顺性。     

手扶拖拉机组制动性能的试验研究

通过对手扶拖拉机组制动初速度、载重量、制动力矩和道路等因子的试验和分析，得出影响机组制动性能的各因子定量数学表达式．     

虚拟仪器技术在拖拉机性能测试中的应用

采用虚拟仪器技术建立了一套方便而有效的拖拉机性能检测系统,分析了拖拉机的制动力、轴重、车速、灯光、烟度、噪音等检测的原理和实现方法,提出了一套基于多功能数据采集卡(DAQ)和图形化编程语言Labview的虚拟仪器构建方案.从硬件构成和软件功能上对虚拟仪器检测线的功能进行了详细介绍.经实际试验表明,检测仪器具有较高的精度.     

拖拉机碳烟排放微机检测系统

设计了拖拉机碳烟颗粒排放微机自动检测系统,系统由取样探头、烟度计、检测仪及笔记本电脑组成.检测仪由单片微机控制,实现对烟度的实时检测,并配有键盘显示接口、打印机接口和标准串行通讯接口,既可单独使用,也可与计算机组成检测系统.检测软件用VB6.0设计,包括串行数据通讯模块、实时检测模块、数据库管理模块等.使用表明,检测系统具有操作简单、检测速度快、测量精度高、自动判断超标排放等特点,是农机监理部门对拖拉机进行科学管理的简便检测系统.     

柴油机漏气率对其性能影响的研究

采用对比试验的方法 ,研究了柴油机缸内气体泄漏对其动力性和经济性的影响。研究结果表明 :漏气不仅带走质量和内能 ,同时也影响发动机的燃烧过程。随着漏气率的增大 ,柴油机有效功率非线性下降 ,而耗油率非线性上升 ,且耗油率的上升率大于功率的下降率 ;同时表明不能单一用静态时气缸最高压力作为发动机送修的判定依据     

A simulation model of 2WD tractor performance

The aim of this study was to develop a model that can accurately simulate the performance of a 2WD tractor with a suspended working implement (cultivator) on various types of soil. The following performance indicators were assessed with the use of the developed model: tractor's overall efficiency, tractive efficiency, specific fuel consumption and soil productivity. The proposed model supports the determination of performance indicators accounting for the overall loss of energy during machine operation. Overall efficiency is such an indicator. The value of this parameter varies significantly subject to changes in tractive force from 0 to 7 kN for the analyzed values of the fuel injector control signal and the total transmission ratio in the third (3L), fourth (4L) and fifth (1H) gear. For this reason, the above indicator may be used to determine the optimal parameters of tractor performance. The above variability was not reported in respect of the coefficient of tractive efficiency.     

拖拉机性能自动检测车的研制

研究了一种拖拉机性能自动检测车，该检测车采用机，电，液，电子和计算机等综合技术，具有操作简单，测试项多，测试精度高等特点，能对拖拉机的左右制动性能，轴重，车速，烟度，灯光，噪声进行自动测试，实际应用表明，该新型测车可作为农机管理部门，拖拉机检测和维修部门开展拖拉机年检审工作和技术状态检测的设备。     

Using a vision sensor system for performance testing of satellite-based tractor auto-guidance

A vision sensing system for the measurement of auto-guidance pass-to-pass and long-term errors was implemented to test the steering performance of tractors equipped with auto-guidance systems. The developed test system consisted of an optical machine vision sensor rigidly mounted on the rear of the tested tractor. The center of the drawbar hitch pin point was used as the reference from which to measure the deviation of the tractor's actual travel path from its desired path. The system was built and calibrated to a measurement accuracy of better than 2 mm. To evaluate the sensor, two auto-guidance systems equipped with RTK-level GNSS receivers were tested and the results for different travel speeds compared. Pass-to-pass and long-term errors were calculated using the relative positions of a reference at a collocated point when the tractor was operated in opposite directions within 15 min and more than 1 h apart, respectively. In addition to variations in speed, two different auto-guidance steering stabilization distances allowed for comparison of two different definitions of steady-state operation of the system. For the analysis, non-parametric cumulative distributions were generated to determine error values that corresponded to 95% of the cumulative distribution. Both auto-guidance systems provided 95% cumulative error estimates comparable to 51 mm (2 in.) claims and even smaller during Test A. Higher travel speeds (especially 5.0 m/s) significantly increased measured auto-guidance error, but no significant difference was observed between pass-to-pass and long-term error estimates. The vision sensor testing system could be used as a means to implement the auto-guidance test standard under development by the International Standard Organization (ISO). Third-party evaluation of auto-guidance performance will increase consumer awareness of the potential performance of products provided by a variety of vendors.     

复合HCCI模式下进气温度对燃烧和排放特性的影响

【目的】改善均质压燃(HCCI)的燃烧状况,降低排放.【方法】试验在一台改装的HCCI发动机上通过增加缸内直喷系统,研究进气温度对HCCI发动机的燃烧、排放特性及其对性能的影响.【结果】进气温度对缸内压力和压力升高率及瞬时放热率的影响十分显著,缸内压力、压力升高率及瞬时放热率的峰值都随着进气温度的升高而增大(缸内压力变化的最大值约1.5 MPa,瞬时放热率的差值最大约为0.05kJ/℃A),且其出现的曲轴转角位置都有所提前.复合HCCI模式下,随着进气温度的升高,CO和HC的排放都有所降低,NOx的排放先降低后升高(进气温度为140℃时接近零排放),但总体处在较低的范围.【结论】进气温度对HCCI发动机影响比较显著,进气温度的提高有利于HCCI的燃烧,使得发动机的性能得到提升,排放得到改善.     

化肥不合理施用中负外部性产生的原因、表现及对策研究

分析了化肥不合理施用中负外部性产生的原因及表现形式,并提出消除负外部性的对策建议。负外部性主要表现有:农业生产中化肥的不合理施用,影响农业效益的提高;化肥施用结构不合理,破坏土壤结构,加剧土壤污染;施肥方法粗放,化肥养分吸收率低,造成农业生产的大气污染;部分区域化肥的过量施用,加剧农业面源污染。消除化肥施用负外部性的对策有发展生态农业,平衡施肥、合理施肥;以市场需求引导企业生产,优化化肥供应结构;完善农业技术推广与服务,引导农户科学施肥等等。     

土壤氧气可获得性对双季稻田温室气体排放通量的影响

为探讨土壤氧气可获得性(SOA)对双季稻田温室气体排放的影响,利用静态箱气相色谱法对多种管理措施影响下稻田温室气体排放通量和土壤氧化还原电位(Eh)、pH值及田间淹水深度(H)等3种SOA因子进行了观测。结果表明,甲烷(CH₄)排放最集中的Eh值、pH值和H范围分别为-100-0mV、5 < pH < 6和1-5cm,3个范围内分别观测到48.8%、61.1%和77.0%的CH₄排放,其中H对CH₄排放影响最明显,单独由其就可解释37.8%的CH₄排放通量(P < 0.0001)。对于氧化亚氮(N₂O),观测到较多的负通量,其纯排放最密集的3种SOA因子的范围分别是:0-100mV、5 < pH < 6和1-5cm,而200-300mV是其排放的临界Eh范围,高于此范围N₂O排放极少。厌氧的反硝化过程是双季稻田N₂O产生的主导过程。可为水稻田温室气体排放机理研究提供基础数据。     

发动机性能试验数据处理方法的研究

研究了发动机性能试验数据处理的方法 ,提出利用最小二乘分段多项式拟合方法对曲线进行拟合 ,可提高工作效率和试验精度 ;认为坐标变换法可提高拟合精度 ;最后采用二元列表函数的线性插值法 ,实现了大气修正的计算机处理。     

轮式拖拉机牵引力影响因素分析

用力学分析的方法对轮式拖拉机挂钩牵引力的形成及影响因索进行了理论分析。寻求改善牵引条件,提高牵引力的途径。提出在发动机功率不变的前提下,可采取改变轮式拖拉机负荷分布等几项可行的措施,提高轮式拖拉机的牵引力。     

高原地区双燃料发动机功率性能试验

针对高原地区进气压力较低导致的双燃料发动机功率下降等问题,对ZS1115单缸沼气/柴油双燃料发动机进行了功率恢复试验研究,研究了压缩比对发动机功率、燃油消耗率和排气温度的影响.结果表明:将沼气/柴油双燃料发动机压缩比改装为19∶1时,达到了原柴油机压缩比为17∶1时的功率水平,燃油消耗率和排气温度降低,达到了节省能源降低有毒气体排放,提高经济效益的效果.     

拖拉机线控液压转向系统的联合仿真

随着农业机械的智能化、自动化程度不断提高,线控转向技术在拖拉机等农用车辆上的应用得到了重视和研究,为了指导拖拉机线控液压转向的研究,缩短开发周期。本文在分析线控液压转向系统的控制算法与结构的基础上,建立其联合仿真模型。基于AMESim软件平台建立液压系统模型,以及整车模型;利用Simulink分别建立模糊免疫PID、模糊PID、常规PID的控制器模型,通过Visual C++6.0实现接口通讯,完成了传动比为1时的转角响应、转角跟随的联合仿真,以及在拖拉机车速15 km/h,方向盘转角180°,传动比为9时的横摆角速度响应、质心侧偏角响应等联合仿真。模糊免疫PID控制可以获得0.272 s的阶跃响应时间、1.182°的跟随误差、3%的横摆角速度响应超调量、0.85°/s的质心侧偏角响应稳态值,均优于常规PID与模糊PID。联合仿真具有较强的参考价值,模糊免疫PID控制应用于线控液压转向系统可以获得理想的控制效果。     

The effect of ozone and drought on the photosynthetic performance of canola

Canola plants were fumigated in open-top chambers with ozone(O_3)(120 ppb)under well-watered(WW)and water-stressed(WS)conditions for 4 weeks.Non-fumigated plants were also studied to facilitate comparison between treatments for the same week and over time.Therefore,the treatments were:WW,WW-O_3,WS and WS-O_3.The fast chlorophyll a fluorescence transients OJIP for the four treatments emitted upon illumination of dark-adapted leaves were measured after week 1,2,3,4 and analysed by the JIP-test to evaluate the resulting changes in photosynthetic performance.Ozone fumigation led to a decline of total performance index(PI_(total))in well-watered plants.The effect of O_3 was minor under drought conditions,as revealed by a decrease of PI_(total) by 3%.The PI_(total) decreased as the treatment was prolonged,due to leaf ageing for all cases and the decline was more pronounced under WW-O_3.Taking the average of all weeks,WW had the highest PI_(total )and the lowest WW-O_3(decrease by 27%),while in WS and WS-O_3,it was lower than WW(14 and 17%,respectively).We found that the absorption(ABS)/reaction centre(RC)increases,while the maximum quantum yield of primary photochemistry(φ_(Po))undergoes slight changes,and trapping(TR_0)/RC closely followed the increase in ABS/RC.This indicates that O_3and drought caused an increase in the functional antenna size.The maximum quantum yield of primary photochemistry showed slight differences for all treatments and over time,suggesting that this parameter is less sensitive to drought and O_3 stress.Therefore,the more sensitive components of the photosynthetic electron transport chain appeared to be the probability that an electron from the intersystem electron carriers is transferred to reduce end electron acceptors at the PSI acceptor side(δ_(Ro))and the RC density on a chlorophyll basis(RC/ABS).     

能量和蛋白质营养对动物繁殖性能的影响

本文比较系统地介绍能量和蛋白质营养状况对动物繁殖性能影响的研究成果，并着重回顾了营养不足时繁殖动物的异常表现，以及繁殖动物饲养过程中满足各种能量和蛋白质营养需要的必要性。     

Statistical analysis on reliability and serviceability of caterpillar tractor

For further understanding reliability and serviceability of tractor and to furnish scientific and technical theories, based on the promotion and application of it, the following experiments and statistical analysis on reliability (reliability and MTBF) serviceability (service and MTTR) of Donfanghong-1002 and Dongfanghong-802 were conducted. The result showed that the intervals of average troubles of these two tractors were 182.62 h and 160.2 h, respectively, and the weakest assembly of them was engine part.     

柴油机排放污染中微粒物的生成机制及影响因素

分析了柴油机排放污染物的构成、排污微粒物的生成机制和影响因素，以及降低微粒物和氮氧化物的技术措施和发展方向。