【作者】 谢涛；

【导师】 姚崇；

【作者基本信息】 哈尔滨工程大学 ， 动力工程及工程热物理， 2018， 硕士

【摘要】 当前针对船用天然气发动机的新技术突破很大部分集中在对电控系统的研究,尽管近年来大量仿真软件简化了开发设计流程,但是天然气发动机作为一种多变量、耦合性强、参数实时变化的被控对象,仅依靠仿真建模无法获得完全真实的数据。因此,本研究针对玉柴YC6K天然气发动机,设计开发了完整电控系统,对软硬件底层驱动和发动机管理系统都进行了详细设计,并实际配机完成了一系列实验以验证控制系统。在此基础上通过实验深入研究了天然气发动机转速与空燃比之间的协调关系及控制方式。空燃比是天然气发动机核心参数之一,如何在各工况下保持适当空燃比以确保充分燃烧满足排放与经济性要求是控制系统研究的关键之一。不同于车用发动机完全基于扭矩的控制,船用发动机需实现各工况下的转速要求,即控制发动机在满足经济性排放性的前提下,依据车钟输入的目标转速实现一定调速动力性。因此本文针对天然气发动机空燃比与转速两个关键控制要素展开研究,并通过实验分析两者协调控制的耦合关系,并提出新的控制策略再结合实验验证得出一定规律。本研究开发的天然气发动机控制器能够对节气门开度,点火提前角,喷射脉宽等实现精确独立控制,可在不同工况下完成转速与空燃比协调控制。实验证明,应用自调整PID空燃比闭环策略可以较好的保证稳态时空燃比的稳定性,通过实验标定了前馈MAP使得空燃比控制取得较好的瞬态响应。经过实验,先将目标空燃比设为定值即当量值,通过改变负载得到不同工况的实际空燃比,再将数据标入MAP作为新的目标值,以此完善了控制策略。最后通过突加突卸负荷和设定转速目标值两种方式在瞬态工况下测试了控制效果,通过实验研究了该型天然气发动机转速与空燃比的控制规律,并验证了控制系统的动力性。更多还原

【Abstract】 At present,the breakthrough of new technology for marine natural gas engine is mainly focused on the research of electronic control system.In recent years,a large number of simulation software has shorted the development cycle of the engine control system,but as a multivariable,coupled strong,real-time changes in parameters of the controlled object,the natural gas engine is not possible to obtain completely authentic data by simulation modeling alone.Therefore,this study aimed at Yuchai Machinery Co.,Ltd YC6 K natural gas engine,designed and developed a complete electronic control system,then designed the hardware and software of the bottom drive and the engine management system in detail,and completed a series of experiments to verify the control system through the actual matching machine.On this basis,the coordination relationship and control mode between the speed and air-fuel ratio of natural gas engine are studied deeply through experiments.Air-fuel ratio is one of the core parameters of natural gas engine,how to maintain proper air-fuel ratio to ensure full combustion in various working conditions is also one of the key factors in control system research.Unlike automotive engine based on torque control,the marine engine is based on rotational speed control,that is,to control the engine to achieve a certain speed regulation power relying on the target speed of the car clock under the precondition of satisfying the economic emission requirement.So this paper studies the air-fuel ratio and rotational speed which are the two key control elements of natural gas engine,and analyses coupling relationship of coordinated control between them through the experiment,and puts forward a new control strategy combined with experimental verification to get a certain rule.The developed natural gas engine controller by this study can control the throttle opening,ignition advance angle,injection pulse width and so on precisely and independently,and can achieve the coordinated control of rotational speed and air-fuel ratio under different operating conditions.The experimental results show that the closed-loop strategy of auto-tuning PID can guarantee the stability of the steady-state time and space combustion ratio,and the feedforward MAP is used to obtain a better transient response of the air-fuel ratio.After the experiment,the target Air-fuel ratio is set to the fixed value equivalent value,the actual air-fuel ratios of different working conditions are got by changing load,then the values are labeled on the MAP as the new target Air-fuel ratio,and the control strategy is perfected.At last,the control effect is tested in transient condition by means of sudden adding and sudden unloading load and set rotational speed target value,and the control law of the speed and air-fuel ratio of this type of natural gas engine is experimentally studied,and the power of the control system is verified.更多还原