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采用两种不同型号的温度限制器配装某型发动机进行飞行试验。试验时,其中一台发动机出现了空中停车。通过对试验数据的分析,结合温度限制器的工作原理,明确了发动机停车原因,给出了解决措施,并进行了地面及飞行验证试验。通过本次试验,可以为发动机的研制及外场排故提供参考。 相似文献
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《内燃机与配件》2017,(4)
在两台不同型号的车用柴油机上进行WHTC及ETC循环排放测试试验,以研究WHTC冷启动循环、WHTC热启动循环及ETC循环下发动机排放(CO、HC、NO_X、PM)特性差异。试验结果表明:WHTC冷启动循环下发动机排气温度及冷却水温度在0~800s范围内均低于WHTC热启动循环,总体排放明显偏高,其中CO、HC及PM排放差距较大,NO_X排放差距则相对较小;WHTC循环下排气温度及冷却水温度在循环绝大部分时间范围内均低于ETC循环,总体排放明显偏高,其中CO、HC及NO_X排放差距较大,PM排放差距则相对较小;该试验结果可为柴油机节能减排研究提供技术支持和研究经验。 相似文献
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通过发动机台架试验确定了仿真计算的边界条件数据;利用GT-SUITE系列软件建立了大学生方程式赛车冷却系统的计算模型,并首次建立赛车的赛道速度循环工况,通过仿真模拟发动机冷机起动暖机过程及循环工况中发动机温度变化,并对标实车试验进行验证;针对现有赛车冷却系统存在的暖机时间长、停机后发动机出现热浸现象、发动机工作温度过低等问题,从散热器、水泵、节温器三方面开展优化,并对其结果进行性能预测。结果表明,优化后的冷却系统可使发动机处于最佳工作温度附近,怠速暖机时间减少16%,停机后未出现热浸现象,耐久赛油耗降低1.7%。 相似文献
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首先对某飞机飞行数据进行总结,得到某发动机入口总温的预测模型。根据得到的发动机入口总温预测模型,对发动机最大状态控制计划试飞方法进行设计规划。试飞结果显示:发动机入口总温预测模型有效指导了发动机最大状态控制计划试飞,提高了试验效率,节省了试验资源;该发动机最大状态控制计划控制有效,保证了发动机最大状态工作可靠。 相似文献
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发动机性能飞行试验中,关键因素之一是确定发动机进口空气流量。考虑到发动机空中性能确定是一个非常复杂的过程,在飞行试验中,应准备多种方案互为备份,以防止某一特定方案由于若干测量参数失效而无法使用。所以,本文参考和改进了应用于国外某大涵道比发动机的高压涡轮导向器喉道截面流量函数计算法,根据地面台架校准试验,获取基于小涵道比涡扇发动机的高压涡轮导向器喉道无量纲组合参数,将其应用到飞行试验中,利用能量守恒和流量守恒,即可得到发动机进口空气流量。计算结果显示,与Gasturb软件计算结果吻合度高。最后,进行了参数敏感性分析,确定出试验中测量需求精度高的参数,这对小涵道比发动机试飞以及性能确定有很重要的意义。 相似文献
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Duk-Sang Kim Young-Joon Park Seang-Wock Lee Yong-Seok Cho 《Journal of Mechanical Science and Technology》2008,22(1):141-147
Emission regulations for automobiles have become more stringent and the improvement of emission during cold start has been
a major key issue to meet these regulations. Among many kinds of factors that affect cold start operation, ignition timing
is crucial to improve emission characteristics due to the influence on exhaust gas temperature. Recent progress in variable
valve timing allows optimized valve event strategies under various ranges of engine operating conditions including cold start.
This study investigates effects of ignition and exhaust valve timing on exhaust gas temperature, combustion stability and
emission characteristics through cold start bench tests of an SI engine.
Experimental results show that exhaust valve timings and ignition timings significantly affect exhaust gas temperature and
stability of engine operation under cold start condition. Exhaust valve timing also affects CO and NOx emission due to changes in residual gas fraction of the combustion chamber. Ignition timing mainly affects exhaust gas temperature
and HC emission. A control strategy, advanced exhaust valve timing and retarded ignition, is plausible in order to achieve
reduction of exhaust emission while maintaining stability under cold start operation of SI engines. 相似文献
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Cha-Lee Myung Ahyun Ko Juwon Kim Kwanhee Choi Sangil Kwon Simsoo Park 《Journal of Mechanical Science and Technology》2013,27(12):3893-3902
This study compares the engine operating behavior and regulated gaseous emissions characteristics between the reference European cycles (ESC/ETC) and the worldwide harmonized driving cycles (WHSC/WHTC), which will be applied in the Euro VI heavy-duty diesel engine emissions regulations, for the diesel particulate filter (DPF) equipped Mercedes 12 L diesel engine. The speed and load distribution for two additional representative harmonized cycles which cover a more realistic operating range for a heavy duty engine were established to verify the engine performance over wide range of the cycle work, fuel consumption, and exhaust system temperature as well as engine coolant temperature for repeated validation tests. The WHTC, including an additional test with cold start and transient operation before the hot start, had a substantial influence on the THC, CO, NOx, and PM exhaust emissions levels because of the engine heat-up time and temperature rising characteristics of aftertreatment device. Moreover, the different engine operating conditions of the WHSC influenced on the specific engine performance and gaseous emissions behavior unlike those of the ESC. Finally, the statistical analysis results through repeated tests validated the stationary and transient cycles running at the fully warm-up condition, however, those of WHTC were closely dependent on the inclusion of cold start condition or aggressive acceleration gradient of engine speed and load trace. 相似文献
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Absence of elastohydrodynamic lubricating (EHL) film causes piston wear in low speed cold initial engine start up, while shearing of low viscosity lubricant in few cycles affects its load carrying capacity. Shear heating effects are incorporated in 2-D hydrodynamic and EHL model by solving 2-D heat equation. EHL pressures are calculated using inverse solution technique. Comparative analysis is based on viscous dissipation coupled with piston motion, changes in pressure, film thickness and viscosity. This study suggests that the increase in temperature varies with speed to affect piston eccentricities, viscosity and film thickness. This optimizes low start up speed for a few engine cycles. 相似文献
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发动机起动方式有气起动、电起动、电气联合起动三种方式,通常以空气起动为主,电起动为辅。在低温季节没发动机难以起动便采用电气联合起动方式。经调查发现柴油发动机在使用过程中大多采用电起动方式,造成加速机件磨损、电瓶消耗等现场;日常使用操作和维护不正确也导致发动机空气起动故障率高等现象。通过对柴油发动机空气起动系统的构造原理的了解,根据实际故障现象进行故障分析及排查。 相似文献
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涡轴型发动机冷却通风系统参数在机动试飞中的变化规律与分析 总被引:1,自引:0,他引:1
涡轴型发动机是直升机的主要动力,而直升机具有机动能力强、灵活的特点。本文以某型涡轴发动机配装某型直升机为研究对象,在高温条件下,对各种机动动作进行了全面的考核,通过对试验数据的总结,归纳、分析了冷却通风系统参数在机动飞行中的变化规律。 相似文献