研究了一种扩大气动量仪电子柱量程的方法.以典型的差压式气动量仪电子柱为例,研究不同条件下气动量仪电子柱的实际输出特性曲线.通过对比不同特性曲线,提出"虚拟标件"的概念,在保留原有符合精度要求的线性段的基础上改进算法,扩大了测量范围,并进行了实验验证.实验结果表明,在保证精度的前提下,气动量仪电子柱的量程扩大了两倍,证明了方法和算法是可行的.相较于其他方法,该方法不需要升级原有的硬件设施,不增加成本,更易于实现,便与推广.
During the working process of the sanitation sweeper, it needs to be parallel to the curb and keep a certain distance to complete the cleaning work, so the driver must observe whether the distance between the side of the vehicle and the curb meets the working requirements at all times while considering the longitudinal driving. This will undoubtedly increase the workload of drivers, but also bring a lot of driving difficulties, easy to drive fatigue, resulting in traffic accidents. In this case, it is necessary to use the auxiliary driving technology to assist the sanitation sweeper driver to complete the cleaning work. Based on the actual working condition of sanitation sweeper, a scheme suitable for judging the attitude of sanitation sweeper is proposed. A line laser assisted vision rangefinder is designed to judge the attitude of sanitation sweeper. This scheme is simple and easy to operate, and the image processing speed is fast, which is suitable for popularization.
针对目前电动助力转向器在中型清扫车上的应用现状,为了解决电机尺寸过大、应用困难的问题,提出了新型的变传动比传动的设计方案.以某款车型的电动助力转向系统为例,研究了该车所用转向器传动方案及其电机输出力矩变化情况,建立了该转向系统数学模型;结合清扫车使用工况,确定了齿轮齿条变传动比设计参数,进行了相关计算、对比分析,验证了该方案的改进效果.采用新的设计方案可直接缩小助力电机的输出力矩变化范围,降低选取的电机功率值,达到了减小电机尺寸,扩大电动助力转向系统适用范围和节约能源的目的.
The off-design experimental performances of heat pump system using R125/R290 (25/75, mass fraction) blend are investigated by varying the mass flowrate of refrigerant blend. The influences of variable mass flowrate upon system coefficient of performance (COP), discharge temperature, temperature glide(GT) and temperature profile in condenser are analyzed, the system performance comparisons between R125/R290 and substituted refrigerant R22 are carried out. The results show that when the blend mass flowrate increases, compressor power increases linearly, the COP linearly increases at first and then gradually decreases, and an optimum COP of 3.04 is obtained when mixture mass flowrate reaches 1.12 kg/min. The compressor discharge temperature is almost decreased linearly whereas specific mass heating capacity is increased firstly and then it has a drop. The temperature differences between refrigerant and water at the inlet and in the middle of the condenser is gradually increased while the one at the outlet is decreased gradually with a heat transfer pinch point kept in the middle of the heat exchanger. Compared with that of R22, the overall performance has proved that the new refrigerant blend could be a promising substitute for R22, which are of significance for the application of the new refrigerant blends used in heat pump system.
在热泵热水器名义工况下,基于换热器中传热窄点温差的限制,对R32/R290二元混合制冷剂在不同质量配比下热泵循环系统特性进行了热力学计算分析.结果表明,相同工作条件下,混合制冷剂R32/R290的最优质量配比为16/84,系统制热性能系数COPh为4.644,较R22系统提高了6.7％,分别比纯质的R32和R290系统高出3.2％和16.8％;在最优质量配比下,系统冷凝压力为2.308MPa,系统压比为2.793,压缩机排气温度为71.88℃.
R1233zd(E)是一种环保、无毒、不可燃的新型制冷剂,本文将R32与R1233zd(E)混合用于替代热泵热水器传统制冷剂R22.在热泵热水器名义工况下,基于换热器中传热窄点温差的限制,对R32/R1233zd(E)二元混合制冷剂在不同质量配比下热泵循环系统的热力学特性进行计算分析.结果表明,相同工作条件下,混合工质在计算配比范围内COPh均大于R22系统,并存在两个峰值,分别对应于质量配比分别为90/10和46/54,R32/R1233zd(E)的最优质量配比为90/10.在最优配比下,系统制热系数COPh值为4.793分别比纯质制冷剂R22、R32系统的COPh增加10.2％、6.6％.新型混合制冷剂R32/R1233zd(E)很有潜力成为新的热泵替代制冷剂.
