CNG和汽油两用燃料发动机电控单元硬件研究

【作者】 任玉琢；

【导师】 李小兵；

【作者基本信息】 电子科技大学 ， 机械制造及其自动化， 2007， 硕士

【摘要】 CNG是清洁燃料,在发动机应用中相对于汽油燃料具有排放性好和经济性高的优势。而且我国的天然气储量巨大。在汽车中应用CNG燃料,可以充分利用现有的资源,减轻汽车的尾气排放并提高车辆运营的经济性。限于我国汽车工业的发展,CNG燃料的应用研究尚处于起步阶段,专用的CNG燃料发动机尚不多见,CNG加气站等配套设施也不完善。因此,借助汽油机进行CNG燃料的应用研究,开发CNG和汽油两用燃料的发动机系统具有重大现实意义。本文的主要工作如下:分析了CNG和汽油燃料在应用特性上的差别以及不同的CNG供给方式对发动机性能造成的影响,提出了基于AJR 1.8L 2VQSEA 827 NF发动机的两用燃料发动机系统实现方案。介绍了两用燃料发动机系统中重要的传感器并分析了其信号特性,提出了各个信号的调理方式和处理逻辑,并以此设计了硬件的接口电路;根据CNG和汽油喷射阀的特性,分析了两种喷射阀的驱动要求,设计了相关的驱动电路,实现了CNG和汽油喷射阀的可靠驱动并通过了实验验证。从元件选择、EMC设计、元件可靠性保证等几方面分析了ECU系统中硬件可靠性设计的需求,给出了时钟、端口等电路的可靠性设计方案,并重点介绍了CNG喷射阀驱动电路的可靠性设计。最后,结合MAC7111微控制器和ECU中硬件电路的特性,设计了两用燃料发动机管理中数据采集、驱动控制等底层逻辑,为发动机管理系统中高层软件的开发提供了高效、可靠的底层逻辑。整个ECU硬件系统具有传感器接口和CNG、汽油喷射阀的驱动电路,在软件控制下实现了两用燃料发动机系统管理的基本工作。整个两用燃料发动机管理系统可在实验室硬件在环仿真系统的测试下可靠的工作。更多还原

【Abstract】 As a green fuel, CNG features less expense and a rather low exhaust pollution compared to gasoline in the engine fuel application. And our country has a large natural gas storage. Thus, applying CNG in automotives could fully utilize the natural gas resource, reduce the exhaust pollution and operating expense of the vehicles.The research of CNG application is just started due to the automotive industry development domestic. Engines specially designed for CNG are rare and the CNG stations are not fully established. So carrying out the application research of CNG based on gasoline engines and developing bifuel engine system for CNG and gasoline has great significance.This dissertation falls into four aspects below:The differences between CNG and gasoline in the engine application and engine performances under different CNG supply methods are discussed. Then the bifuel engine system solution for CNG and gasoline based on AJR 1.8L 2VQSEA 827 NF gasoline is proposed.Handling logics for sensor signals are developed and related hardware interfaces are designed based on the analysis of important sensors and their signal characteristic; the CNG and gasoline injector characteristic and their demand for driving circuit is introduced. Injector driving circuits are designed, which drive the injectors properly and pass the lab test.The demand of hardware reliability design in automotive environment is analyzed from component selection and EMC design aspects; Solution for clock circuit, I/O port circuit and CNG injector circuit is given. And the most emphasis is laid upon the CNG injector driving circuit reliability design.Last, the data acquisition and actuator driving logics, which provide efficient and reliably low level logic for the upper level software in the engine management system, are developed upon the MAC7111 Microcontroller and former described ECU hardware.The ECU hardware with sensor interface and injector driving circuit could fulfill basic function in bifuel engine management under software control. The whole bifuel engine management system could operate reliably in Hardware-in-the-Loop Simulation under lab environment.更多还原