共查询到18条相似文献，搜索用时 265 毫秒
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本文通过对蓄压式喷油器喷射过程进行模拟计算 ,分析了共轨压力、针阀弹簧预紧力、滑阀节流孔直径、滑阀复位弹簧预紧力和滑阀运动阻力对喷油正时的影响 ,结果表明滑阀是影响蓄压式喷油器喷油正时的主要因素。 相似文献
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高压电控共轨喷油系统的高压容积大、油路长,高压泵增压的容积效率低,同时在增压和回油过程中的能量损失较大,系统的安全性也较差,而蓄压式共轨喷油系统能够克服以上缺点。为此,采用数值模拟方法对蓄压式共轨喷油器进行研究,探讨了喷油器主要结构参数对喷射过程的影响,所得结果对蓄压式共轨喷油器的确定和优化具有一定的参考价值。 相似文献
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介绍了目前应用的电控泵喷嘴和电控高压共轨燃油喷射系统的组成、原理和特点。为满足更为严格的排放法规要求,国外柴油机电控燃油喷射系统采用了高喷油压力、电控蓄压式泵-喷嘴、压电晶体喷油器和高度柔性调节能力的高压喷油系统等新技术。通过分析这些新技术的特点,归纳出柴油机电控燃油喷射系统将向高喷油压力、响应更快、多次喷射、精量控制、高度的柔性调节和低能耗的方向发展。 相似文献
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一、柴油机启动困难原因分析
柴油机是压燃式发动机。因此,要保证它的正常工作,就必须使它具有充分的压燃条件。否则,柴油机的启动就会感到困难。例如,压缩终了气缸压力达不到2940kPa以上,喷油器的喷油量或压力不足、喷油时间失准等,均可导致柴油机不易启动或不能启动。 相似文献
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以一台四缸四冲程的压燃式航空活塞发动机为研究对象,研究了发动机失火时失火缸的缸压峰值变化。通过压燃式航空活塞发动机燃烧系统的仿真,基于AMESim建立了航空活塞发动机模型,并通过实验台架采集到的数据对仿真模型进行验证。以失火时的缸压差值为失火特征,通过在模型中控制喷油脉宽,模拟喷油器故障。研究了在不同转速下,发动机的气缸失火对发动机气缸缸压的影响。结果表明,转速越快,失火特征越小。通过分析每个气缸的缸压变化,可以准确地判断出发动机是否失火和失火缸的位置。 相似文献
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<正>1.漏装出油阀密封垫圈一台新买的泰山—12型拖拉机,刚工作几小时发动机就自行熄火.经查,发现喷油压力很低时喷油器才喷油,当喷油压力调整到4.9MPa时,喷油器就不喷油了.拆卸喷油泵检查 发现出油阀紧座下部未装出油阀密封垫圈.这样当柱塞压油时,压力油向低压油腔泄漏,喷油泵无法输出高压油,喷油压力正常情况下喷油器便无法喷油,因而引起发动机自行熄火.装上油阀密封垫后,故障排除.2.出油阀弹簧弹力不足一台东风—12型手扶拖拉机在更换喷油嘴和柱塞偶件后,起动不到5分钟,发动机就自行熄火,拆下喷油器检查,发现针阀偶件咬死.彻底清除喷油器内的积炭并将喷油压力调至规定值,装复后试车,仍出现上述故障.后来拆下出油阀检查,发现出油阀弹簧的弹力不足.换上新弹簧后,故障随之排除. 相似文献
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外开式汽油喷油器喷雾特性研究 总被引：1，自引：0，他引：1
在定容弹内,采用纹影和激光Mie散射技术研究了外开式压电晶体汽油喷油器使用汽油、正丁醇和乙醇时的喷雾特性。结果表明,外开式喷油器喷油形成的空心圆锥状喷雾结构由线状油束组成。喷油背压对喷雾的宏观形态影响较大。随着喷油背压的升高,喷雾中油线间隙减小并最终消失,同时喷雾贯穿度与面积均大幅减小,但喷雾锥角基本不随背压、燃料种类和时间的变化而变化。此外,随着背压的升高,喷雾横向贯穿度的减小程度大于轴向贯穿度,但是横向贯穿度始终大于轴向贯穿度。粘度较大的乙醇和正丁醇的轴向贯穿度大于汽油。横向贯穿度与喷油产生的涡流有关。涡流尺度越大,则横向贯穿度也越大。 相似文献
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利用HYDSIM软件,通过对液力增压式喷油器的喷射过程进行模拟计算,分析了液力增压式喷油器主要结构参数对喷射过程的影响,为液力增压式喷油器结构参数的优化提供了理论依据。 相似文献
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茎部施药是树木病虫害防治的新型手段.植物茎部施药的要求在树木的表皮下2～3cm处注入相应的药液,为此研制出一种电动树木注射机.该机由充电电池提供动力,带动两直流电机工作.钻孔电机带动钻头钻孔,以便药液注入;药液注射电机带动活塞运动,以一定压力注入药液.注射机对施药深度和施药量按要求由相应的行程开关进行调节,使树木病虫害的防治简单方便.试制样机表明,该机质量小、效率高,且污染较少,适用范围广. 相似文献
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《Journal of Agricultural Engineering Research》1994,57(1):39-52
There are two different design objectives for subsoilers with pressurized fluid injection, for use as pan-breakers or injectors respectively. A large soil failure is desirable when it is used as a pan-breaker and little soil failure is advantageous when it is used as an injector. This paper determines optimum shapes of pan-breaker and injector, where the draught can be reduced by injecting pressurized air (about 1·2 MPa at the air tank) from a nozzle port at the tip of the chisel.The results show that the optimum pan-breaker with fluid injection should have a rake angle of 45 to 60°, a chisel thickness of 50 × 50 mm, and a heel position at 100 mm. The optimum injector with fluid injection should have a rake angle of 90°, a shank thickness of less than 15 mm, a chisel length of 250 mm, a chisel thickness of 30 × 30 mm, and a heel position at 100 mm. 相似文献
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Field evaluation of fertigation uniformity as affected by injector type and manufacturing variability of emitters 总被引：2，自引：1，他引：2
Fertigation with microirrigation systems is increasing in popularity. Uniformity of fertigation is important for many reasons.
Field experiments were conducted to evaluate the effects of injector types and emitters on fertigation uniformity by simultaneously
measuring the distributions of water application, solution concentration, and fertilizer applied within a subunit of microirrigation
system. Three conventionally used injectors, a water-driven piston proportional pump, a venturi device, and a differential
pressure tank, were evaluated with three different emitters. The results indicated that both manufacturing variability of
emitters and injector types had a very significant effect on the uniformity of fertilizer applied, while the uniformity of
water application was mainly dependent on emitter type. The uniformity of solution concentration was dependent on injection
methods. Emitters having a higher manufacturer’s variation produced a more nonuniform distribution of water application and
fertilizer applied. For a given emitter type, a differential pressure tank produced considerably higher coefficients of variation
(Cv) for water application and fertilizer applied than a proportional pump or a venturi injector because a differential pressure
tank released fertilizer in a decreasing rate with time. To obtain a uniform fertigation distribution, an injector that can
inject fertilizers in a constant rate is recommended. The relationship between water application uniformity and fertigation
uniformity for a microirrigation system was established for different injection methods. Cv for fertilizer applied was very
close to water application Cv for a microirrigation system using a proportional pump or a venturi injector as an injection
device. However, fertilizer Cv for a differential pressure tank was approximately double of the water application Cv. The
injection method and injector performance should therefore be considered in the design of microirrigation systems. 相似文献
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微灌用文丘里施肥器综合性能试验研究 总被引：1，自引：0，他引：1
基于文丘里施肥器综合工作性能指标测试研究,以期获得文丘里施肥器结构优化设计建议.研究选用规格为DN 20的6种不同材质的国内外文丘里施肥器,基于不同进口压力和进出口压差条件,系统针对文丘里施肥器在压力能耗、吸肥效率以及振动与空化等综合性能指标开展了测试研究.结果表明:文丘里施肥器吸肥临界压差与进口压力存在显著的线性正相关;相同进口压力下,国内文丘里施肥器最大吸肥量普遍明显低于国外同类产品,且振动与空化现象受压差变化敏感性较强;同一模具下,收缩率较小材质的施肥器制造偏差小,吸肥性能好, UPVC可作为生产施肥器的优选原料之一;此外,文丘里施肥器存在与其内部结构相对应的吸肥量上限,压差增大后导致振动与空化现象的加强是抑制文丘里施肥器吸肥能力进一步提升的重要原因. 相似文献