共查询到19条相似文献,搜索用时 109 毫秒
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采用数值模拟的方法研究了不同制动模式、压缩比、海拔高度等对制动性能的影响。结果表明:压缩比的降低和海拔高度的增加均导致发动机制动功率大幅度降低。提高压缩比和采用二冲程制动模式是提高低压缩比发动机制动功率的有效措施。压缩比为11.6时,与四冲程制动模式相比,二冲程制动模式产生的制动功率可提升69.6%~80.5%,最大缸压低于6.0 MPa的限值,并且其可运行转速范围不受涡轮增压器危险区的限制。当前应用领域中,高压缩比(17.0)发动机上采用四冲程制动模式获得的制动功率最高。由于短期内难以提高低压缩比发动机的压缩比,仅通过在低压缩比(11.6)发动机上采用二冲程制动模式仍可将制动功率提高17.5%~30.4%,最大缸压降低25.2%~29.3%。故在应用天然气机等低压缩比发动机的中重型载货汽车上推荐采用二冲程制动模式,这将大幅度提高车辆制动安全性。 相似文献
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分析了发动机缓速器的工作过程及其制动能力,介绍了两种典型发动机制动的机构特征,工作原理及性能特点等,对目前最新的发动机缓速器技术进行了比较全面的分析. 相似文献
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计算了国标GB 12676Ⅱ型试验条件下,不同重量的重型卡车所需要的制动功率,介绍了发动机辅助制动系统的分类和工作原理,用理论计算和台架试验相结合的方法,研究了以参考制动升功率和发动机排量为关键要素的发动机辅助制动系统的匹配方法。 相似文献
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《内燃机与动力装置》2017,(2):5-8
随着技术的发展,越来越多的电控功能被应用于发动机上,但发动机预热、快速热车目前还停留在简单的进气加热方面,尤其在寒冷天气只靠简单进气加热很难达到快速热车的目的,发动机工作在低温状态对发动机损害较大。因此在排气制动基础上我们推出一种发动机,启动后依靠排气制动蝶阀部分关闭来达到快速热车方案,是电控发动机功能的进一步挖掘、延伸,展现了电控发动机优势。本文重点阐述排气制动快速热车工作原理、相关试验及结论。 相似文献
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《柴油机设计与制造》2014,(2)
正专利名称:一种发动机排气制动控制系统及控制方法申请号:CN201310412021公开号:CN103452676申请人:大连理工大学发明人:连静,李海波,李琳辉,周雅夫,黄海洋,王蒙蒙,化玉伟,孙永朝文摘:本发明公开了一种发动机排气控制系统及控制方法。本发明在排气制动自动开启控制过程中,在制动状态且离合器未分离时,控制单元采 相似文献
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为提高某天然气发动机制动性能,保证行车安全,在对不同发动机辅助制动形式进行分析及研究的基础上,确定采用缸内压缩释放制动的辅助制动形式;对装有缸内压缩释放制动的天然气发动机进行试验,测试气门升程、凸轮轴挺杆接触应力及发动机制动功率等参数,并对比同排量柴油机和天然气发动机的制动功率;进行整车道路试验,测试搭载缸内压缩释放制... 相似文献
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详细介绍一种全新理念的排气制动功测试方案、排气制动耐久考核方法,给出了柴油机排气制动测量结果并与普通柴油机进行了对比试验。 相似文献
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In the present experiment, a computerized single cylinder diesel engine with a data acquisition system was used to study the effects of oxygen enriched combustion technology (OECT) on the performance characteristics. The use of different levels of oxygen-enriched air was compared with respect to percentage load. Increasing the oxygen content in the air leads to faster burn rates and increases the combustibility at the same stoichiometry (oxygen-to-fuel ratio). These effects have the potential to increase the thermal efficiency and specific power output of a diesel engine. The power increases considerably with oxygen enrichment. In addition, oxygen enrichment can also be considered as a way to reduce the sudden loss in power output when the engine operates in a high load condition. Assessed high combustion temperature from the oxygen enriched combustion leads to high combustion efficiency. OECT reduces the volume of flue gases and reduces the effects of greenhouse effects. Engine tests were conducted in the above said engine for different loads and the following performance characteristics like brake power (BP), specific fuel consumption (SFC), mean effective pressure, brake thermal efficiency, mechanical efficiency, and exhaust gas temperature were studied. The objective of this paper is to address, in a systematic way, the key technical issues associated with applying OECT to single cylinder diesel engines. 相似文献
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针对DF4DD型机车装备的DZD型踏面单元制动器频繁发生的闸瓦偏磨问题,对DZD型踏面单元制动器进行改型设计。开发出一种抗闸瓦偏磨的新型机车踏面单元制动器,彻底解决了原有闸瓦偏磨问题,提高了机车的运行可靠性,降低了总体运营成本。 相似文献
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Hydrogen (H2) is being considered as a primary automotive fuel and as a replacement for conventional fuels. Some of the desirable properties, like high flame velocity, high calorific value motivate us to use hydrogen fuel as a dual fuel mode in diesel engine. In this experiment, hydrogen was inducted in the inlet manifold with intake air. The experiments were conducted on a four stroke, single cylinder, water cooled, direct injection (DI), diesel engine at a speed of 1500 r/min. Hydrogen was stored in a high pressure cylinder and supplied to the inlet manifold through a water-and-air-based flame arrestor. A pressure regulator was used to reduce the cylinder pressure from 140 bar to 2 bar. The hydrogen was inducted with a volume flow rate of 4l pm, 6l pm and 8l pm, respectively by a digital volume flow meter. The engine performance, emission and combustion parameters were analyzed at various flow rates of hydrogen and compared with diesel fuel operation. The brake thermal efficiency (BTE) was increased and brake specific fuel consumption (BSFC) decreased for the hydrogen flow rate of 8l pm as compared to the diesel and lower volume flow rates of hydrogen. The hydrocarbon (HC) and carbon monoxide (CO) were decreased and the oxides of nitrogen (NOx) increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen. The heat release rate and cylinder pressure was increased for higher volume flow rates of hydrogen compared to diesel and lower volume flow rates of hydrogen. 相似文献
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建立了BFM1015柴油机气缸盖进气道和冷却水腔的改进设计模型,对进气道的流通特性进行了试验对比和冷却水腔的流场分析对比,完成了气缸盖改进模型的砂芯快速成型和铸造加工。在单缸柴油机试验台上对改进设计的新气缸盖进行了试验研究并和原气缸盖的试验结果进行了对比分析。结果表明:安装新气缸盖的单缸柴油机在高转速时燃油消耗率比安装原气缸盖时明显降低,降幅最高达到7g/(kW.h);在相同负荷下,新气缸盖火力面的温度比原气缸盖显著下降,在排气门鼻梁区温度下降最明显,最高下降61.8K;新气缸盖的传热能力比原气缸盖提高约50%。 相似文献