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车用柴油机低温预热起动技术 总被引:2,自引:2,他引:0
为保证低温条件下迅速可靠起动,在多数柴油机上设有低温起动预热装置,以提高进入气缸的可燃混合气的温度,降低启动阻力矩,在保证顺利启动的同时,减少启动过程中的零件磨损.从结构和使用等方面探讨了低温进气预热和低温发动机预热两种应用技术,对于车用柴油机在低温条件下的顺利启动具有重要意义. 相似文献
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冬天气温低,柴油机起动困难。为了克服这个缺陷,我们通常使用的办法是在柴油机的进气岐管上安装预热器,通过预热发动机的进气,来提高发动机的冷车起动性能,减轻起动电动机的负荷。但在使用过程中,由于一些驾驶员不了解预热器的工作原理和使用维护方法,使预热器过早损坏。 相似文献
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结合天然气的特性,通过理论分析,从动力性角度论述了柴油机改装为天然气发动机所涉及到的关键技术障碍,并从燃料供给系统、燃烧系统、进气系统、点火系统、控制策略等方面探讨了CA498柴油机改装为压缩天然气发动机的技术措施。 相似文献
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《拖拉机与农用运输车》2016,(3):24-26
为了解决非道路电控单体泵柴油机低温启动的问题,分析了低温条件下电控单体泵柴油机启动困难的影响因素。对某电控单体泵柴油机燃油系统、润滑系统和MAP图进行优化,增加进气预热装置,并对柴油机的启动电机和蓄电瓶进行改进。采取各项改进措施后,柴油机的低温启动性能明显提升,满足了北方寒冷地区对农用机械的特殊需求,为非道路国三柴油机的推广奠定了基础。 相似文献
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一、进气预热 进气预热的目的是为了提高进气温度,从而提高气缸内压缩终了时的温度,改善了点火条件。通常采用的方法是用电火花预热器预热。 二、选用特殊的机油 为了减少发动机的起动阻力,通常采用加热机油的方法来降低其粘度,另外还可选用稠化机油,即含 相似文献
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《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
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感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
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The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
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从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献