摘要
21世纪以来由于能源和环境的双重压力，加强以气体燃料取代石油燃料，开发以清洁燃料为主导的低排放和零排放汽车已成为各国当前及今后面临的主要问题之一。高辛烷值气体燃料LPG作为替代能源被广泛地加以应用。目前面临的关键问题是在稀燃条件下提高点火系统电火性能及工作的安全可靠性，从而达到提高发动机热效率和降低排放的目的。因此，本课题以一汽CA6GH-L电控LPG单燃料发动机点火系统为研究对象，采用电喷的形式，从LPG的物化特性出发，研究LPG在发动机点火系统对发动机动力性的影响，在不同工况下通过对电流的稳定控制、实现点火和喷射时刻的实时优化调整以提高现有LPG发动机动力性。
具体研究内容如下：
1、为进一步提高点火系统电火性能及工作的安全可靠性考虑，设计了电子点火系统的电子点火器闭合角可控功能电路、初级回路电阻控制电路、停车断电保护电路和初级电流稳定控制电路。
2、设计了电控高能异步双火花塞点火系统。系统包括新缸头（半球型燃烧室、双火花塞位置、燃烧室内气流组织等）、两套独立的可变点火能量的高能点火系统。通过电控单元ECU及控制策略根据发动机工况的变化，提供可变的同步、异步双火花点火。
3、依据LPG液化石油燃气公交车发动机点火系统工作原理和控制方法，结合发动机上各种传感器的电信号利用单片机设置的程序对发动机进行精确的点火时刻控制。
4、利用MATLAB仿真软件对发动机进行实验分析发动机动力性，主要为确定发动机功率、扭矩及燃气消耗率，并以公交车为对象进行各档位运行状况仿真，以验证LPG高能异步双点火发动机的实际效果。
关键词：LPG公交车发动机，快速燃烧系统，电控点火系统
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Abstract
Since the 21st century due to the double pressure of energy and environment, strengthen to replace petroleum fuels, fuel gas development to clean fuel for cars with low emissions zero discharge current and future world has become one of the major problems facing. High octane fuel gas LPG alternatives such as widely applied. The key problem is facing in j.the conditions to improve the ignition system, electrical fire performance and reliability of work, so as to improve the efficiency and reduce the emissions of the engine.Therefore, the subject to faw CA6GH - L single fuel engine ignition control LPG system as the research object, by ems form, from the chemical properties, LPG engine ignition system in the study of LPG engine performance, the influence of different conditions in the current through the stability control, realizing the ignition and injection time to improve the real-time optimization engine performance existing LPG.
1、in order to further enhance the ignition system, the electrical activity can work and the safety and reliability of the consideration of electronic ignition system, the design of electronic ignition Angle closure, primary loop circuit controlled function resistance control circuit, parking electricity protective circuit and control circuit is the primary current stability.
2、 the design requirements of high-energy spark rapid burning system of double. The new system includes cylinder head (firebox compression ratio, double spark position, the combustion chamber airflow organization, etc.), two sets of independent variable ignition energy high-energy ignition system. Through the electronic control unit (ECU and control strategy according to the condition, provides engine variable synchronous and asynchronous double spark ignition.
3、LPG liquefied petroleum gas bus engine ignition system working principle and control methods, combining various sensor signals on engine microcontroller program to set the precise moment engine ignition control.
4、use MATLAB simulation software to engine for experimental analysis to determine the power, the main engine power, torque and gas consumption by bus, and for each gear operation condition to verify the simulation of LPG high-energy ignition engine asynchronous double the.
Key words ： LPG rapid fire engines，Fast combustion system，electronic ignition system
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目 录
摘要 ..............................................................................................................................................Ⅰ Abstract .......................................................................................................................................Ⅱ
第一章 绪论....................................................................................................................................1 1.1 引言.......................................................................................................................................1 1.2 LPG液化石油燃气公交车发动机点火系统的设计目的和意义......................................1 1.3 LPG液化石油燃气公交车发动机点火系统的设计内容..................................................2 1.3.1 研究LPG液化石油燃气公交车发动机点火系统的原理及其控制方法......................2 1.3.2 研究LPG液化石油燃气公交车发动机点火系统硬件与软件的设计与开发..............2 1.3.3 设计与绘制LPG液化石油气公交车发动机点火系统的典型机械结构图..................3 1.3.4 研究LPG液化石油燃气公交车发动机点火系统的计算机仿真与分析......................3 1.4 本章小结..................................................................................................................................4
第二章 研究LPG液化石油燃气公交车发动机点火系统的原理及其控制方法...................5 2.1 基于CA6GH-L电控LPG单燃料发动机点火系统的工作原理及其控制方法................5 2.1.1 CA6GH-L电控LPG单燃料发动机点火系统的工作原理及其控制方法....................5 2.1.2 LPG发动机点火系统系统的组成与基本原理...............................................................7 2.1.3 LPG发动机电子点火系统系统的组成与基本原理.......................................................8 2.1.4 微机控制点火系统点火提前角的确定............................................................................9 2.1.5 发动机爆震的控制过程..................................................................................................11 2.1.6 基于微机控制发动机高能异步双点火系统控制方法的提出......................................12 2.2 CA6GH-L电控LPG单燃料发动机点火系统的闭环控制的原理...................................14 2.3 本章小结...............................................................................................................................15
第三章 研究LPG液化石油燃气公交车发动机点火系统硬件的设计与开发.......................17 3.1 基于CA6GH-L电控LPG单燃料发动机的系统结构原理...............................................19 3.1.1 发动机的选择..................................................................................................................20 3.2 基于CA6GH-L电控LPG单燃料发动机点火系统的硬件设计.......................................21 3.2.1 LPG发动机电子点火系统的磁感应信号发生器的组成及工作原理..........................22 3.2.2 LPG发动机电子点火器电路的设计与开发..................................................................24 3.2.3 LPG公交车发动机燃烧室的选择原则及其特性..........................................................26
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3.2.4 点火方式对LPG公交车发动机的燃烧过程的影响......................................................27 3.2.5 火花塞位置优化及高能点火的优点..............................................................................29 3.2.6 ECU的硬件结构设计......................................................................................................30 3.3 设计与绘制LPG公交车发动机点火系统的典型机械结构图.........................................33 3.3.1 LPG发动机点火系统总电路图的目的和意义..............................................................33 3.3.2 LPG发动机点火控制系统电路图的目的和意义..........................................................33 3.3.3 LPG发动机燃烧室的组成与尺寸的选择......................................................................34 3.3.4 燃烧室的设计和CAD图纸的绘制.................................................................................34 3.4 本章小结.................................................................................................................................34
第四章 研究LPG液化石油燃气公交车发动机点火系统软件的设计与开发.....................36 4.1 LPG液化石油燃气公交车发动机点火系统软件的结构原理..........................................36 4.2 单片机MC9S12DP256程序设计.......................................................................................37 4.3 ECU的控制软件设计 .........................................................................................................38 4.3.1 程序流程图......................................................................................................................38 4.3.2 系统软件的功能..............................................................................................................39 4.3.3 输入捕捉和输出比较的中断服务程序..........................................................................39 4.3.4 程序算法说明..................................................................................................................41 4.3.5 程序以及分析..................................................................................................................42 4.4 本章小结...............................................................................................................................42
第五章 研究LPG液化石油燃气公交车发动机点火系统的计算机仿真与分析.................44 5.1 MATLAB软件的介绍..........................................................................................................44 5.2 基于CA6GH-L电控LPG单燃料发动机点火系统的仿真实验目的..............................44 5.3 基于CA6GH-L电控LPG单燃料发动机点火系统仿真实验选用的实验装置….…….45 5.4 CA6GH-L电控LPG单燃料发动机不同工况下的点火实验分析...................................45 5.4.1 LPG高能异步双点火发动机外特性曲线的仿真计算.................................................45 5.5 LPG高能异步双点火发动机与原柴油发动机动力性仿真对比......................................49 5.6 LPG高能异步双点火发动机的燃气消耗率仿真实验分析..............................................50 5.7 总结.......................................................................................................................................52
第六章 总结................................................................................................................................53 参考文献........................................................................................................................................55
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致谢................................................................................................................................................56 附录1 ............................................................................................................................................57 附录2 ............................................................................................................................................65
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