【作者】 吴小飞；

【导师】 乔安平；

【作者基本信息】 太原理工大学 ， 动力机械及工程， 2008， 硕士

【摘要】 排放法规的日益严格、环境保护问题的日益严峻以及石油资源的日益短缺,对现有的内燃机技术提出了更为严峻的挑战。在内燃机上采用稀薄燃烧技术,可以扩大内燃机的空燃比,使得燃料在气缸内燃烧更加充分,可以有效降低燃油消耗率和有害物质的排放。由于发动机采用稀薄燃烧方式,缸内可燃混合气浓度变稀,点燃它需要更多的点火能量。本课题主要针对内燃机稀燃点火系统,开发可以控制稀燃发动机实现以能量叠加方式点火的控制电路,为进一步研究稀燃发动机的点火控制提供实验依据。点火控制电路的硬件部分是以Atmel公司生产的AT89S52单片机作为控制单元,针对稀燃发动机点火系统的控制要求,设计了单片机的电源电路、晶振和复位电路、I/O接口扩展电路、键盘电路、信号发生器电路、抗干扰电路、转速显示电路以及相关的驱动电路等。设计中严格按照电路板的设计要求,选择合适的元器件以及电路布线规则,提高点火控制电路板的可靠性。点火控制电路的软件部分包括对按键和信号发生器触发点火信号两种方式的程序设计,通过正确的软件设计实现对点火电路精确的时间控制。软件设计中多采用模块设计方法,提高了程序的可读性。主要包括芯片初始化模块、时间延时模块、按键识别模块、转速显示模块、单片机外部中断模块和单片机定时器中断模块等,软件设计能够对外部信号触发做出识别,根据稀燃发动机的点火特性,确定程序中重要参数的数值。按照相应的触发方式输出准确的点火信号波形、点火频率以及相应的电压值,实现稀燃发动机的能量叠加点火。对内燃机稀燃点火控制电路的硬件和软件在数字示波器上进行实验测试。分别在按键触发和信号发生器两种外部控制信号的输入下,在不同的输入转速和频率下,对示波器的输出信号进行分析和总结。实验结果表明,本课题中的稀燃点火控制电路板设计和控制多个点火信号输出的软件设计都很好的实现了点火信号和频率输出,输出的波形可以满足发动机能量叠加点火要求。本点火控制系统不仅可以准确的实现对点火电路的时间控制,而且可以适应很宽的转速范围,使得该点火系统不仅可以可靠的应用于通用点燃式发动机,也可以对超高速发动机实现点火控制。更多还原

【Abstract】 With the emission control regulations and the environmental protection being increasingly stricter and stem as well as the shortage of the oil resource, the present technology of internal combustion engine (ICE) faces more challenges than ever before. The air/fuel ratio can be increased and the fuel can be combusted more completely in the cylinder by applying the lean-burn technology on internal combustion engine. With this technology, the oil consumption and the emission of the deleterious matter can be effectively decreased. As the engine works under the lean-burn condition, the mixture in the cylinder becomes lean. Much more spark ignition energy should be supplied in order to ignite the lean mixture. In this project, an electric circuit board is designed and made to meet the requirement of the ICE’s lean-burn ignition system which operates under the mode of superposed energy ignition. Further research on the ignition control of the lean-burn ICE can make use of the result in this project.The hardware of the lean-burn ICE’s ignition control circuit designed for the ignition control requirement of the lean-burn ICE, based on the single-chip microcomputer (SCM) AT89S52 produced by the Atmel company. These circuits include the SCM’s power circuit, the crystal oscillator and reset circuit, the I/O interface extended circuit, the keyboard circuit, the signal generator circuit, the anti-jamming circuit, the rotate speed display circuit the correlative drive circuit and so on. The circuit design strictly conforms to the rules for designing the printed-circuit board. Proper components and routing rules are selected to increase the operation reliability of the circuit board.The software of the ignition control circuit consists of two kinds of program design for the key-press and square-wave that trigger the control circuit to output ignition signal. The timing of the ignition circuit is accurately controlled by designing the right software. Modularized design is used for the software to increase the readability of the program. The whole software mainly includes the chip initial module, the delay module, the key-press identifying module, the rotate speed display module, the SCM’s external interrupt module and the timer interrupt module. According to the ignition characteristic of lean-burn ICE, the software should distinguish the external signal trigger to definite the value of the important parameter in the program. Exact ignition signal wave, the frequency and the voltage value should be output under the corresponding trigger.The hardware of the ignition control circuit board and software are validated on the digital oscillograph. The external control signal is input either by key-press trigger or signal generator trigger. The output of the oscillograph is analysed and summarized on the condition of different rotate speed or frequency makes the board work. The experimental results show that the design of the ignition control circuit board and the software can accurately output ignition signal as well as its frequency. The wave meets the requirement of superposed energy ignition.The ignition control system not only preciously makes the time of ignition circuit under control, but also adapts wide range of rotate speed. The ignition control system can be reliably used not only for the general spark ignition engines but for the high rotate speed engines.更多还原