共查询到17条相似文献,搜索用时 187 毫秒
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为解决某型两级可调增压柴油机变海拔、变工况增压压力控制复杂问题。采用GT-POWER软件建立两级可调增压柴油机高海拔工作过程模型,利用试验数据进行了模型校核。设计了两级可调增压柴油机涡轮旁通阀变海拔控制策略,优化标定得到了高/低压级涡轮旁通阀最佳开度和最佳增压压力。采用仿真与试验相结合手段,比较了基于增压压力PID闭环控制和基于涡轮旁通阀开度的开环控制对柴油机高海拔瞬态性能的影响。结果表明:采用PID闭环控制,相比平原,3000、5000 m海拔增压压力首次达到目标值90%的时间分别增加了0.11、0.19 s。涡轮旁通阀开环控制与闭环控制相比,0、3000和5000 m首次达到目标增压压力的时间分别缩短了0.09、0.197和0.14 s,但实际增压压力与目标增压存在偏差。基于此,采用增压压力PID闭环反馈控制与涡轮旁通阀开环控制相结合的控制算法能够同时兼顾两级增压系统瞬态过程的鲁棒性和准确性,是未来高海拔两级增压系统瞬态过程的理想控制算法。 相似文献
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利用一维仿真软件,建立某涡轮增压柴油机的仿真模型,与实验结果基本吻合,说明仿真结果具有一定精度。基于上述模型,对该涡轮增压柴油机与可变喷嘴增压器匹配进行数值模拟研究。其稳态工况性能模拟计算结果表明,该增压器与柴油机匹配良好,并可以有效改善发动机经济性,提高低速扭矩。 相似文献
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为了研究柴油机可调两级增压系统,采用 GT-POWER 软件对 WP7 型柴油机可调两级增压系统进行一维建模和仿真分析,分别对稳态工况和动态工况下的仿真计算结果进行验证。结果表明:对于稳态工况,不同负荷条件下循环气缸压力、燃烧放热率的计算结果和试验结果有着非常好的一致性,其中气缸压力计算值与试验值的最大绝对误差为 0.157 MPa,最大相对误差为 1.07%,比燃油耗和进气压力的计算值和试验值也非常吻合,整个负荷范围内比油耗计算值与试验值的最大相对误差为 1.26%,进气压力计算值与试验值的最大相对误差为 1.21%;对于动态工况,扭矩、转速和增压压力变化曲线的计算值和试验值均能吻合得较好,变化趋势基本一致,增压压力计算值和试验值的最大绝对误差约为 14.1 kPa,最大相对误差为 4.85%。该柴油机可调两级增压系统仿真模型具有较高的计算精度。 相似文献
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VNT增压柴油机与整车速度瞬态响应的试验分析 总被引:3,自引:0,他引:3
对装有可变喷嘴涡轮增压器(VNT)的柴油机客车在高原地区与平原地区上的起动、起步加速、换挡加速及减速等变工况下瞬态特性进行了试验研究。对VNT的瞬时转速、发动机转速、汽车速度等参数进行了对比分析。研究结果表明,起动时,VNT转速滞后于发动机的转速;起步加速工况,VNT转速随发动机转速变化的瞬态响应快;换挡加速工况,VNT的转速随发动机转速增加而增加;减速工况,发动机转速下降,VNT转速呈现下降趋势。VNT的有效调节,控制了涡轮不超速,可以改善涡轮增压柴油机的瞬态特性,有利于整车变工况行驶性能的提高。 相似文献
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可调涡轮增压器改善柴油机低速扭矩特性的试验研究 总被引:6,自引:0,他引:6
为考察可调涡轮增压器对柴油机低速扭矩特性的影响,将所研制的VGT-70A型转叶式可调涡轮增压器与J6110Z型柴油机匹配进行了性能试验。介绍了试验设备和试验方法。试验结果表明,VGT-70A型增压器具有在全工况范围内与柴油机良好匹配的潜力,特别是在提高低速扭矩储备方面有明显效果。 相似文献
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利用GT-Power软件建立某V型柴油机仿真模型,并进行了可调两级增压系统的匹配。模拟计算了不同海拔条件下发动机全工况运行时高压级涡轮旁通阀开度对燃油消耗率的影响。结果表明,高压级涡轮旁通阀开度是通过发动机指示效率与泵气损失间接影响燃油消耗率。同一工况下,发动机燃油消耗率按其主要影响因素的不同分为示效率主导区、泵气损失主导区以及两者综合影响区。且随着海拔的升高,影响发动机燃油消耗率的指示效率主导区域扩大,泵气损失主导区域减小。最后,以最佳燃油经济性为指标,得到变海拔全工况下涡轮旁通阀最佳阀门开度。 相似文献
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Numerical study of a light-duty diesel engine with a dual-loop EGR system under frequent engine operating conditions using the doe method 总被引:1,自引:0,他引:1
J. Park K. S. Lee S. Song K. M. Chun 《International Journal of Automotive Technology》2010,11(5):617-623
Exhaust gas recirculation (EGR) is an emission control technology that allows for a significant reduction in NOx emissions
from light- and heavy-duty diesel engines. The primary effects of EGR are a lower flame temperature and a lower oxygen concentration
of the working fluid in the combustion chamber. A high pressure loop (HPL) EGR is characterized by a fast response, especially
at lower speeds, but is only applicable if the turbine upstream pressure is sufficiently higher than the boost pressure. On
the contrary, for the low pressure loop (LPL) EGR, a positive differential pressure between the turbine outlet and the compressor
inlet is generally available. However, a LPL EGR is characterized by a slow response, especially at low and moderate speeds.
In this study, of the future types of EGR systems, the dual-loop EGR system (which has the combined features of the high-pressure
loop EGR and the low-pressure loop EGR) was developed and was optimized under five selected operating conditions using a commercial
engine simulation program (GT-POWER) and the DOE method. Finally, significant improvements in the engine exhaust emissions
and performance were obtained by controlling several major variables. 相似文献
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Turbocharging port-injected Natural Gas (NG) engines allows them to recover gaseous-fuel related power gap with respect to
gasoline engines. However, turbolag reduction is necessary to achieve high performance during engine transient operations
and to improve vehicle fun-to-drive characteristics. Significant support for the study of turbocharged Compressed Natural
Gas (CNG) engines and guidelines for the turbo-matching process can be provided by 1-D numerical simulation tools. However,
1-D models are predictive only when a careful tuning procedure is set-up and carried out on the basis of the experimental
data. In this paper, a 1-D model of a Heavy-Duty (HD) turbocharged CNG engine was set up in the GT-POWER (Gamma Technologies
Inc., Westmont, IL, US) environment to simulate transient operations and to evaluate the turbolag. An extensive experimental
activity was carried out to provide experimental data for model tuning. The model buildup and tuning processes are described
in detail with specific reference to the turbocharger model, whose correct calibration is a key factor in accounting for the
effects of turbine flow pulsations. The second part of the paper focuses on the evaluation of different strategies for turbolag
reduction, namely, exhaust valve variable actuation and spark timing control. Such strategies were aimed at increasing the
engine exhaust-gas power transferred to the turbine, thus reducing the time required to accelerate the turbocharger group.
The effects of these strategies were examined for tip-in maneuvers at a fixed engine speed. Depending on the engine speed
and the applied turbolag reduction strategy, turbolag reductions from 70% to 10% were achieved. 相似文献
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Pressure model based coordinated control of VGT and dual-loop EGR in a diesel engine air-path system
This paper describes a pressure-model-based coordinated control method of a variable geometry turbine (VGT) and dual-loop exhaust gas recirculation (EGR) in a diesel engine air-path system. Conventionally, air fraction or burnt gas fraction states are controlled for the control of dual-loop EGR systems, but fraction control is not practical since sensors for fractions are not available on production engines. In fact, there is still great controversy over how best to select control outputs for dual-loop EGR systems. In this paper, pressure and mass flow states are chosen as control outputs without fraction states considering the availability and reliability of sensors. A coordinated controller based on the simple control-oriented model is designed with practical aspects, which is applicable for simultaneous operations of high pressure (HP) EGR, low pressure (LP) EGR, and VGT. In addition, the controller adopts the method of input-output linearization using back-stepping to solve the chronic problems of conventional pressure-based controllers such as coupling effects between operations of HP EGR, and VGT. The control performance is verified by simulation based on the proven GT-POWER model of a heavy-duty 6000cc diesel engine air-path. 相似文献