共查询到20条相似文献,搜索用时 31 毫秒
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《车用发动机》2020,(1)
针对VNT-EGR技术在国六柴油机上的应用,研究了VNT与EGR耦合对柴油机经济性和排放特性的影响规律。通过VNT与EGR开度的正交试验,并结合喷油参数进行与柴油机的优化匹配。研究结果表明:VNT增压器与EGR同时工作时,EGR开度增加导致可利用的排气能量降低,增压器的效率向低效率区域移动,减小VNT开度可改善这一现象;相同EGR开度下,减小VNT开度可以提高柴油机的空燃比,在炭烟排放水平相同的条件下,可以实现更大的EGR率,进一步降低NO_x比排放,炭烟与NO_x的总体排放水平有所降低,燃油消耗率随VNT开度的减小呈先降低后升高的趋势,是泵气损失与缸内燃烧状况共同作用的结果;VNT与EGR开度的正交优化大幅度降低了NO_x比排放,烟度与油耗有所上升,但低速大负荷的经济性会有所改善,配合喷油参数优化,可以在满足NO_x原排的条件下,经济性最优。 相似文献
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对于采用EGR技术路线的多缸柴油机,EGR在各缸均匀分布可以确保燃烧质量,降低裸机排放。建立了某六缸国ⅣEGR柴油机进气管三维模型,采用一维和三维模拟软件相结合,对EGR在进气管内的分布进行了流动机理的模拟分析,评估了EGR各种导入方案以及进气管相关零部件结构设计对EGR和空气混合的影响。对模型进行了CFD稳态计算,研究了4种节气门位置对EGR和空气混合的影响。 相似文献
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应用0-D单区HCCI发动机模型耦合乙醇氧化反应详细化学动力学机理,对乙醇HCCI发动机的工作区域进行了模拟研究。确定了由过量空气系数(φa)和EGR率表示的HCCI工作区域,分析了工作区域内的排放性能、动力性能以及指示热效率。研究结果表明,在无EGR的工况下,从a=3.2到φa=8.5乙醇可以实现HCCI燃烧,φa<3.2时,出现爆震,必须加入EGR才能抑制爆震燃烧,最大的EGR率达到52%。在HCCI工作区域内,NOx排放较低,最大排放为140×10-6,CO排放较高,φa和EGR率对其影响很大。工作区域内的热效率较高,最大可达到34%,指示平均有效压力受EGR的影响较大,最大峰值达0.5 MPa。 相似文献
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A. Mehmood S. Laghrouche M. El Bagdouri 《International Journal of Automotive Technology》2013,14(6):941-953
This paper presents a detailed physical model of an electro-pneumatic system, used to control Variable Geometry Turbochargers (VGT). The VGT actuator system consists of two parts, a diaphragm based pneumatic actuator and a solenoid based Electro-pneumatic Pressure Converter (EPC). The proposed model copes with the pressure dynamics inside the pneumatic actuator, with special focus on the EPC. The dynamics of both parts have been modeled separately and combined into one model by parameterizing the effective flow area and the air mass flow through the pneumatic actuator. The variations in volume, temperature and air mass flow rate have been taken into account. The model so obtained serves mainly for studying the effect of actuator dynamics on the global engine system. For control purposes, the detailed model is simplified to reduce the calculation load. Both models are validated using experimental data obtained from an engine test bench. 相似文献
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I. Ballo 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》1995,24(9):683-691
The paper deals with the theoretical estimation of the minimal power requirement, necessary for the operation of the active vibration control system (AVCS), connected with a passive one. It is assumed this compound system is used for the vibration control purposes in the heavy vehicle driver's seats. The systems considered in the paper are of two kinds. In the first case the electro-hydraulic actuator of the AVCS is situated in series to the spring-damper combination of the seat suspension. The second system under consideration is formed by parallel connection of electro-pneumatic actuator and the spring-damper combination of the seat suspension, which is a mechanical model of a real air spring with controlled in-flow and out-flow of the air. The comparison of results for both compound systems shows markedly higher power consumption of the serial system. The theoretical results are in acceptable agreement with the experimental data. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(9):683-691
SUMMARY The paper deals with the theoretical estimation of the minimal power requirement, necessary for the operation of the active vibration control system (AVCS), connected with a passive one. It is assumed this compound system is used for the vibration control purposes in the heavy vehicle driver's seats. The systems considered in the paper are of two kinds. In the first case the electro-hydraulic actuator of the AVCS is situated in series to the spring-damper combination of the seat suspension. The second system under consideration is formed by parallel connection of electro-pneumatic actuator and the spring-damper combination of the seat suspension, which is a mechanical model of a real air spring with controlled in-flow and out-flow of the air. The comparison of results for both compound systems shows markedly higher power consumption of the serial system. The theoretical results are in acceptable agreement with the experimental data. 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(9):1438-1465
In this paper, a synthesis method for a reconfigurable fault-tolerant control system for use in a steer-by-wire vehicle is proposed. The vehicle considered in this paper is also assumed to have independently driven wheels. The control objective in this work is to enable the vehicle yaw rate to track the reference signal even when the steering actuator breaks down. Since the vehicle yaw rate can be controlled with either the front wheel turn angle or the yaw moment generated by the independently driven wheels, this system has actuator redundancy. We attempt to design a control system that manages this actuator redundancy so that the performance degradation due to the actuator failure is minimised. We utilise a control allocator based on on-line optimisation for managing the actuator redundancy. The fault-tolerant control system with a control allocator has several excellent properties. For example, the method can handle various failure situations. Also, since the control allocation problem is reduced to a convex quadratic programming problem, the on-line computational effort is relatively little. However, so far, it has been unclear whether the stability of the control system with the control allocator is guaranteed when the actuator failure occurs. Therefore, we propose a design method of a fault-tolerant controller based on on-line optimisation that guarantees the stability of the overall system. The effectiveness of the method is established through numerical examples. 相似文献
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线控制动系统防抱死特性模糊控制方法的仿真研究 总被引:2,自引:1,他引:2
作者研究分析了直接影响汽车行驶安全性能的汽车制动系统的重要组成部分,阐述了以油或空气作为传力介质的传统制动系统必将被全电的制动系统——线控制动系统所取代,线控制动系统是未来制动系统的发展方向。介绍了线控制动系统的分类、结构和工作原理;建立了线控制动系统和制动执行器的数学模型,以1/4车辆模型为研究对象,设计了模糊控制器,并在Matlab/Simulink下进行了仿真分析。仿真结果表明,模糊控制对线控制动系统的防抱死特性取得了理想的控制效果。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(9):653-669
This paper addresses modelling, longitudinal control design and implementation for heavy-duty vehicles (HDVs). The challenging problems here are: (a) an HDV is mass dominant with low power to mass ratio; (b) They possess large actuator delay and actuator saturation. To reduce model mismatch, it is necessary to obtain a nonlinear model which is as simple as the control design method can handle and as complicated as necessary to capture the intrinsic vehicle dynamics. A second order nonlinear vehicle body dynamical model is adopted, which is feedback linearizable. Beside the vehicle dynamics, other main dynamical components along the power-train and drive-train are also modelled, which include turbocharged diesel engine, torque converter, transmission, transmission retarder, pneumatic brake and tyre. The braking system is the most challenging part for control design, which contains three parts: Jake (engine compression) brake, air brake and transmission retarder. The modelling for each is provided. The use of engine braking effect is new complementary to Jake (compression) brake for longitudinal control, which is united with Jake brake in modelling. The control structure can be divided into upper level and lower level. Upper level control uses sliding mode control to generate the desired torque from the desired vehicle acceleration. Lower level control is divided into two branches: (a) engine control: from positive desired torque to desired fuel rate (engine control) using a static engine mapping which basically captures the intrinsic dynamic performance of the turbo-charged diesel engine; (b) brake control: from desired negative torque to generate Jake brake cylinder number to be activated and ON/OFF time periods, applied pneumatic brake pressure and applied voltage of transmission retarder. Test results are also reported. 相似文献
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Xiao-Yun Lu J. Karl Hedrick 《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2005,43(9):653-669
This paper addresses modelling, longitudinal control design and implementation for heavy-duty vehicles (HDVs). The challenging problems here are: (a) an HDV is mass dominant with low power to mass ratio; (b) They possess large actuator delay and actuator saturation. To reduce model mismatch, it is necessary to obtain a nonlinear model which is as simple as the control design method can handle and as complicated as necessary to capture the intrinsic vehicle dynamics. A second order nonlinear vehicle body dynamical model is adopted, which is feedback linearizable. Beside the vehicle dynamics, other main dynamical components along the power-train and drive-train are also modelled, which include turbocharged diesel engine, torque converter, transmission, transmission retarder, pneumatic brake and tyre. The braking system is the most challenging part for control design, which contains three parts: Jake (engine compression) brake, air brake and transmission retarder. The modelling for each is provided. The use of engine braking effect is new complementary to Jake (compression) brake for longitudinal control, which is united with Jake brake in modelling. The control structure can be divided into upper level and lower level. Upper level control uses sliding mode control to generate the desired torque from the desired vehicle acceleration. Lower level control is divided into two branches: (a) engine control: from positive desired torque to desired fuel rate (engine control) using a static engine mapping which basically captures the intrinsic dynamic performance of the turbo-charged diesel engine; (b) brake control: from desired negative torque to generate Jake brake cylinder number to be activated and ON/OFF time periods, applied pneumatic brake pressure and applied voltage of transmission retarder. Test results are also reported. 相似文献